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Wyświetlanie 1-26 z 26
Tytuł:
Forbidden Subgraphs for Collapsible Graphs and Supereulerian Graphs
Autorzy:
Liu, Xia
Xiong, Liming
Powiązania:
https://bibliotekanauki.pl/articles/32361726.pdf
Data publikacji:
2022-05-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
forbidden subgraph
supereulerian
collapsible
Opis:
In this paper, we completely characterize the connected forbidden subgraphs and pairs of connected forbidden subgraphs that force a 2-edge-connected (2-connected) graph to be collapsible. In addition, the characterization of pairs of connected forbidden subgraphs that imply a 2-edge-connected graph of minimum degree at least three is supereulerian will be considered. We have given all possible forbidden pairs. In particular, we prove that every 2-edge-connected noncollapsible (or nonsupereulerian) graph of minimum degree at least three is Z3-free if and only if it is K3-free, where Zi is a graph obtained by identifying a vertex of a K3 with an end-vertex of a Pi+1.
Źródło:
Discussiones Mathematicae Graph Theory; 2022, 42, 2; 417-442
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of the Impact of OBE-Based Teaching Reform on Students’ Learning Experiences : From the Perspective of Self-Determination Theory
Autorzy:
Liu, Xia’nan
Somasundram, Piriya A/P
He, Yanbin
Powiązania:
https://bibliotekanauki.pl/articles/2233945.pdf
Data publikacji:
2023-06-30
Wydawca:
Wydawnictwo Adam Marszałek
Tematy:
outcome-based education
self-determination theory
academic
achievement
learning satisfaction
Opis:
This study employed a questionnaire survey method and utilised the Self-Determination Theory as a theoretical framework to simulate students’ “needs”. The aim was to investigate the impact of OBE-based teaching reform on students’ academic achievement, satisfaction, autonomy, competence, and relatedness. The study used a quasi-experimental research design with 80 students from Changzhi Medical College as the sample and found that OBE teaching can improve students’ academic achievement, especially for middle and low-performance students. It can improve students’ satisfaction with the course and relatedness experience.
Źródło:
The New Educational Review; 2023, 72; 108-121
1732-6729
Pojawia się w:
The New Educational Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design of broadband power line communication module for automatic meter reading
Autorzy:
Chen, Xia
Liu, Ling
Powiązania:
https://bibliotekanauki.pl/articles/949869.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
automatic meter reading
low-power consumption
long-distance transmission
power line communication
Opis:
Low-power consumption and long-distance transmission are two problems that have to be solved by the application of broadband power line communication for the automatic meter reading system. To reduce the power consumption of the communication module, based on the analysis of the composition of the power consumption, some methods are proposed. From the communication chip level and the module circuit level, the design scheme of low-power consumption is given. To solve the problem of transmission distance, a frequency band of 2.44 MHz~5.6 MHz is used as the main working frequency band. The communication module supports multiple frequency bands. Using this feature, the optimal frequency band is adaptively selected for communication and automatic switching, which further improve the transmission distance. Field application shows that the above methods effectively decrease the power consumption of the communication module and extend the transmission distance.
Źródło:
Archives of Electrical Engineering; 2020, 69, 4; 771-780
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Uncertainty evaluation of multilateration-based geometric error measurement considering the repeatibility of positioning of the machine tool
Autorzy:
Liu, Xingbao
Xia, Yangqiu
Rui, Xiaoting
Powiązania:
https://bibliotekanauki.pl/articles/2206791.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
sequential-multilateration
laser tracker
machine tool
geometric error
measurement uncertainty
Opis:
The sequential multilateration principle is often adopted in geometric error measurement of CNC machine tools. To identify the geometric errors, a single laser tracker is placed at different positions to measure the length between the target point and the laser tracker. However, the measurement of each laser tracker position is not simultaneous and measurement accuracy is mainly subject to positioning repeatability of the machine tool. This paper attempts to evaluate the measurement uncertainty of geometric errors caused by the positioning repeatability of the machine tool and the laser tracker spatial length measurement error based on the Monte Carlo method. Firstly, a direct identification method for geometric errors of CNC machine tools based on geometric error evaluation constraints is introduced, combined with the geometric error model of a three-axis machine tool. Moreover, uncertainty contributors caused by the repeatability of positioning of numerically controlled axes of the machine tool and the laser length measurement error are analyzed. The measurement uncertainty of the geometric error and the volumetric positioning error is evaluated with the Monte Carlo method. Finally, geometric error measurement and verification experiments are conducted. The results show that the maximum volumetric positioning error of the machine tool is 84.1 μm and the expanded uncertainty is 5.8 μm ( = 2). The correctness of the geometric error measurement and uncertainty evaluation method proposed in this paper is verified compared with the direct geometric error measurement methods.
Źródło:
Metrology and Measurement Systems; 2023, 30, 1; 49--63
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Smart Substation Network Fault Classification Based on a Hybrid Optimization Algorithm
Autorzy:
Xia, Xin
Liu, Xiaofeng
Lou, Jichao
Powiązania:
https://bibliotekanauki.pl/articles/227220.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
smart substation
network fault classification
improved separation interval method (ISIM)
support vector
machine (SVM)
Anti-noise processing (ANP)
Opis:
Accurate network fault diagnosis in smart substations is key to strengthening grid security. To solve fault classification problems and enhance classification accuracy, we propose a hybrid optimization algorithm consisting of three parts: anti-noise processing (ANP), an improved separation interval method (ISIM), and a genetic algorithm-particle swarm optimization (GA-PSO) method. ANP cleans out the outliers and noise in the dataset. ISIM uses a support vector machine (SVM) architecture to optimize SVM kernel parameters. Finally, we propose the GA-PSO algorithm, which combines the advantages of both genetic and particle swarm optimization algorithms to optimize the penalty parameter. The experimental results show that our proposed hybrid optimization algorithm enhances the classification accuracy of smart substation network faults and shows stronger performance compared with existing methods.
Źródło:
International Journal of Electronics and Telecommunications; 2019, 65, 4; 657-663
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new method for decision making problems with redundant and incomplete information based on incomplete soft sets: From crisp to fuzzy
Autorzy:
Xia, Sisi
Chen, Lin
Liu, Siya
Yang, Haoran
Powiązania:
https://bibliotekanauki.pl/articles/2172131.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
decision-making
soft set
incomplete fuzzy soft set
incomplete information
redundant information
podejmowanie decyzji
zbiór miękki
informacja niepełna
informacja zbędna
Opis:
This research is focused on decision-making problems with redundant and incomplete information under a fuzzy environment. Firstly, we present the definition of incomplete fuzzy soft sets and analyze their data structures. Based on that, binary relationships between each pair of objects and the “restricted/relaxed AND” operations in the incomplete fuzzy soft set are discussed. After that, the definition of incomplete fuzzy soft decision systems is proposed. To reduce the inconsistency caused by the redundant information in decision making, the significance of the attribute subset, the reduct attribute set, the optimal reduct attribute set and the core attribute in incomplete fuzzy soft decision systems is also discussed. These definitions can be applied in an incomplete fuzzy soft set directly, so there is no need to convert incomplete data into complete one in the process of reduction. Then a new decision-making algorithm based on the above definitions can be developed, which can deal with redundant information and incomplete information simultaneously, and is independent of some unreliable assumptions about the data generating mechanism to forecast the incomplete information. Lastly, the algorithm is applied in the problem of regional food safety evaluation in Chongqing, China, and the corresponding comparison analysis demonstrates the effectiveness of the proposed method.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2022, 32, 4; 657--669
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on a novel hybrid shielding structure of magnetic coupler for inductive power transfer system
Autorzy:
Liu, Yun Rui
Wang, Chunfang
Xia, Dongwei
Yue, Rui
Powiązania:
https://bibliotekanauki.pl/articles/1841326.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
coupling coefficient
electromagnetic shielding
finite element simulation
optimization design
wireless power transfer
współczynnik sprzężenia
ekranowanie elektromagnetyczne
symulacja elementów skończonych
optymalizacja projektu
bezprzewodowy transfer mocy
Opis:
With the development of wireless power transfer technology, more and more attention has been paid to its electromagnetic safety. In this paper, a novel hybrid shielding structure composed of the innermost fan-shaped ferrite, the interlayer nanocrystalline stripand the outermost aluminum foil is proposed to shield the electromagnetic field of the inductive power transfer system. Eight structure parameters of the proposed shielding areoptimized by finite element simulation, in order to reduce the magnetic leakage of the system and improve the utilization rate of shielding materials. In addition, the proposed structure is compared with two types of typical double-layer hybrid shielding from the perspectives of the weight, the coupling coefficient and the magnetic flux leakage. Both simulation and experiment results show that the cost and weight of the proposed shield are about 60% lower than the traditional disk shield. More over, the shielding layer proposed in this paper can not only effectively reduce the magnetic flux leakage of the system, but also maintain a high coupling coefficient.
Źródło:
Archives of Electrical Engineering; 2021, 70, 1; 129-143
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Noether Theorems and Discrete Variational Integrators in Field Theory
Autorzy:
Xia, Li-Li
Chen, Li-Qun
Liu, Chang-Xin
Powiązania:
https://bibliotekanauki.pl/articles/1398640.pdf
Data publikacji:
2015-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
02.20.Sv
11.30.-j
Opis:
The discrete analogue of the Noether-type identities in field theory is investigated by means of the difference discrete variational principle in which the difference is regarded as an entire geometric object. The discrete counterparts of the Noether theorems are obtained. It is proved that there exists the discrete version of the Noether conservation law in field theory. The discretization for the nonlinear Schrödinger equation is presented to illustrate the results.
Źródło:
Acta Physica Polonica A; 2015, 127, 3; 669-673
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation on Irreversible Expansion of 1,3,5-Triamino-2,4,6-trinitrobenzene Cylinder
Autorzy:
Sun, J.
Kang, B.
Zhang, H.
Liu, Y.
Xia, Y.
Yao, Y.
Liu, X.
Powiązania:
https://bibliotekanauki.pl/articles/357936.pdf
Data publikacji:
2011
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
TATB
irreversible expansion
XRD
lattice parameters
Opis:
In this study, the irreversible expansion of TATB cylinder is investigated. No evident variation of the lattice parameters is observed on TATB crystal. The density of TATB powder decreases by only about 0.02% after it suffered from thermal cycling process at the range from -54 C to 74 C, while the density of TATB cylinder decreases by about 1.0%. It is suggested that the density variation of TATB powder has little contribution to the density decrease of TATB cylinder. Therefore, the increasing interstices between TATB powder originated from the thermal cycling should be responsible to the irreversible expansion of TATB cylinder.
Źródło:
Central European Journal of Energetic Materials; 2011, 8, 1; 69-79
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Biosorption of Pb(II) by the resistant Enterobacter sp. : Investigated by kinetics, equilibrium and thermodynamics
Autorzy:
Liu, Lei
Xia, Mengya
Hao, Jianwen
Xu, Haoxi
Song, Wencheng
Powiązania:
https://bibliotekanauki.pl/articles/2073764.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Pb(II)
biosorption
enterobacter sp.
kinetics
thermodynamics
Opis:
The Pb(II)-resistant bacterium was isolated from heavy metal-contained soils and used as a biosorbent to remove Pb(II). The strain was identified as Enterobacter sp. based on the 16S rRNA sequence analysis. The effect of biosorption properties (pH value, Pb(II) concentration, bacterial concentration and temperature) on Pb(II) was investigated by batch experiments. Results of FTIR and XPS showed that the biosorption process mainly involved some oxygen-containing groups (-OH and -COOH groups). The experimental results and equilibrium data were fitted by pseudo-second-order kinetic model and Langmuir model, respectively. The experimental biosorption isotherms fitted the Langmuir model, and the maximum biosorption capacity was 40.75 mg/g at 298 K. The calculated ΔGо and ΔHо were –4.06 and 14.91(kJ/mol), respectively, which indicated that biosorption process was spontaneous and endothermic. Results show that Enterobacter sp. will be an efficient biosorbent for Pb(II) removal.
Źródło:
Archives of Environmental Protection; 2021, 47, 3; 28--36
2083-4772
2083-4810
Pojawia się w:
Archives of Environmental Protection
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Performance analysis of the fractional-order vehicle mechatronic ISD suspension with parameter perturbation
Autorzy:
Shen, Yujie
Hua, Jie
Xia, Xiaohua
Liu, Yanling
Yang, Xiaofeng
Powiązania:
https://bibliotekanauki.pl/articles/2086945.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
vehicle suspension
mechatronic inerter
fractional order
parameter perturbations
Opis:
This paper concerns the performance analysis of a fractional-order vehicle mechatronic ISD suspension with parameter perturbation. A dynamic model of the vehicle mechatronic ISD suspension based on a fractional-order electrical network is constructed. The superiority of the vibration isolation performance of the fractional-order ISD suspension is demonstrated, and the dynamic performance of the suspension is analyzed considering perturbation of parameters. Results show that the inertance has an important role when the frequency is above 103 Hz, and the fractional inductance order and fractional capacitance order have significant impact in the frequency range of 10−2 Hz to 102 Hz.
Źródło:
Journal of Theoretical and Applied Mechanics; 2022, 60, 1; 141--152
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of pick layouts on the performance of bolter miner cutting head
Autorzy:
Qiao, S.
Wang, A. L.
Xia, Y. M.
Liu, Z. Z.
Liu, J. S.
Yang, M.
Powiązania:
https://bibliotekanauki.pl/articles/88893.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Wydział Geoinżynierii, Górnictwa i Geologii. Instytut Górnictwa
Tematy:
optimum
pick layout
bolter miner
FEM
coal-rock cutting
load fluctuation
Opis:
A bolter miner is a new type of mining machinery with cutting and anchoring functions. In order to study the best pick layout of bolter miner cutting head. Based on the constitutive relation of Holmquist-Johnson-Cook (HJC), three simulation models of different cutting heads were established, and the whole crushing process of coal-rock was simulated by finite element method (FEM). The influence of the cutting head on the cutting performance under the condition of different rotational speeds and pick layouts was intensively studied. The results show that the relationship of load fluctuation coefficient among the three pick layouts is as follows: sequential type > hybrid type I > checkerboard type. The circumferential pick layouts can reduce the load fluctuation coefficient of cutting head. The rotational speed from 20 to 40 r/min, the torque linearly decreases with the increase of rotational speed. The rota-tional speed increases from 40 to 50 r/min, the cutting torque is relatively stable. The specific energy of chessboard type is relatively higher than the other three cutting heads. The difference of specific energy between sequential type and hybrid type I is not more than 5.5%, and the reality of the simulation is verified by cutting experiments. The results were successfully applied to the first shield type bolter miner in China.
Źródło:
Mining Science; 2018, 25; 147-160
2300-9586
2353-5423
Pojawia się w:
Mining Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Finite element analysis of load characteristic of shield bolter miner cutting head under complex coal seam condition
Autorzy:
Qiao, S.
Xia, Y. M.
Liu, Z. Z.
Liu, J. S.
Ning, B.
Wang, A. L.
Powiązania:
https://bibliotekanauki.pl/articles/89071.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Wydział Geoinżynierii, Górnictwa i Geologii. Instytut Górnictwa
Tematy:
complex coal seam
shield bolter miner
load characteristic
specific energy
load fluctuation
Opis:
Aiming at the complex conditions of the first shielded bolter miner in the actual work, the mechanical model of bolter miner cutting head was established. Based on cutting mechanism of the conical pick and the cutting head, the cutting head load and torque analysis model under complex coal seam were established. The dynamic characteristics of load and torque in the process of cutting head are analyzed under three different working conditions of cutting roof-coal layers, coal-floor layers and coal seam by finite element method. The results show that when the damage variable D=1, the coal-rock completely lacks the bearing capacity, and it forms arc-shaped crushing groove on the coal-rock. The large difference of torque between roof-coal layers and the roof-coal layers in the conical pick is 112 Nm, which indicates that the cutting head has the best performance with cutting the coal seam first and then cutting the rock. In the process of excavation, the load fluctuation coefficient of cutting the coal-floor layers and roof-coal layers is about 1.2 times of that of the coal seam. The results can provide a reference for the efficient cutting and performance evaluation of the bolter miner.
Źródło:
Mining Science; 2017, 24; 85-97
2300-9586
2353-5423
Pojawia się w:
Mining Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Identification and tissue distribution of a novel rat glucocorticoid receptor splice variant
Autorzy:
Ju, Huiming
Wang, Xia
Liu, Zongping
Liu, Ping
Zhao, Yan
Xiong, Renping
Zhou, Yuanguo
Chen, Xingyun
Powiązania:
https://bibliotekanauki.pl/articles/1040640.pdf
Data publikacji:
2009
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
glucocorticoid
glucocorticoid receptor
receptor isoform
splice variant
Opis:
Glucocorticoid receptor (GR) is a steroid hormone receptor that has been shown to play important roles in diverse cellular and physiological processes. More and more evidence has revealed that the effects of glucocorticoids are mediated by the glucocorticoid receptor through genomic or nongenomic mechanisms. A growing number of glucocorticoid receptor splice variants have been identified in human tissues, but few are known in rat tissues. In this work, a novel rGR cDNA, called rGRβ, was cloned from Sprague Dawlay (SD) rat liver. Sequence analysis revealed that the rGRβ mRNA was 39 base pairs (bp) shorter than the rGR mRNA reported earlier. The deleted segment is located in exon 1 and encodes 13 repeated glutamine residues. Both the rGR and rGRβ mRNAs were quantitated by Northern blot hybridization using non-homologous glucocorticoid cDNA probes. Results showed that the rGR and rGRβ mRNAs were most abundant in the lung, the least abundant in the heart, and there were more rGR and rGRβ mRNAs in the kidney than in the liver. The identification of rGRβ may contribute to the understanding of the genomic or nongenomic effects of glucocorticoids.
Źródło:
Acta Biochimica Polonica; 2009, 56, 1; 109-113
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effects of velvet antler polypeptides on the phenotype and related biological indicators of osteoarthritic rabbit chondrocytes
Autorzy:
Zhang, Zhengyao
Liu, Xiaofeng
Duan, Lengxin
Li, Xia
Zhang, Yang
Zhou, Qiuli
Powiązania:
https://bibliotekanauki.pl/articles/1039876.pdf
Data publikacji:
2011
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
velvet antler polypeptides
MMP
osteoarthritic chondrocytes
apoptosis
Opis:
Objective: To study the effects of velvet antler polypeptides (VAPs) on osteoarthritic chondrocytes (OCs) in rabbits. Methods: An osteoarthritic rabbit model was established according to Hulth's method. OCs were isolated and cultured for observation of the cell cycle. Cell proliferation was detected by MTT assay and the cell cycle was monitored by flow cytometry. The phenotype was determined by toluidine blue staining as well as immunohistochemical staining for collagen type II. The expression of MMP-1, MMP-3, MMP-13, TIMP-1, and collagen I and X mRNA by chondrocytes was assayed by RT-PCR. Results: The VAPs had no obvious proliferative effect on OCs and did not affect the cell cycle. However, they significantly reduced the proportion of early apoptotic cells in a dose-dependent manner. Further, VAPs inhibited the expression of collagen I and X mRNA and induced abnormal expression of MMP-1 and MMP-13 mRNA. VAPs had no significant effect on MMP-3 and TIMP-1 mRNA levels. The toluidine blue and collagen type II immunohistochemical staining intensities of VAP-treated chondrocytes were positively correlated with the concentration of VAPs used. Conclusion: VAPs had no significant effect on OC proliferation and the cell cycle, but did increase the glycosaminoglycan (GAG) and collagen type II expression levels in the extracellular matrix, and down-regulated collagen I and X mRNA expression. Treatment of cartilage cells with VAPs maintained their normal phenotype, inhibited matrix metalloproteinases (MMPs) secretion, kept the balance of cartilage matrix metabolism, and sustained an external environment where the cartilage cells could survive. Moreover, VAPs reduced the proportion of early apoptotic cells, suggesting that they may block the apoptotic pathway in OCs.
Źródło:
Acta Biochimica Polonica; 2011, 58, 3; 297-302
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An improved angle calibration method of a high-precision angle comparator
Autorzy:
Xia, Yangqiu
Wu, Zhilin
Huang, Ming
Liu, Xingbao
Mi, Liang
Tang, Qiang
Powiązania:
https://bibliotekanauki.pl/articles/1848955.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
angle calibration
position error
complete closure method
method verification
Opis:
Angle calibrations are widely used in various fields of science and technology, while in the high-precision angle calibrations, a complete closure method which is complex and time-consuming is common. Therefore, in order to improve the measurement efficiency and maintain the accuracy of the complete closure method, an improved calibration method was proposed and verified by the calibration of a high-precision angle comparator with sub-arc-second level. Firstly, a basic principle and algorithm of angle calibration based on complete closure and symmetry connection theory was studied. Then, depending on the pre-established calibration system, the comparator was respectively calibrated by two calibration methods. Finally, by comparing En values of two calibration results, the effectiveness of the improved method was verified. The calibration results show that the angle comparator has a stable angle position error of 0.17′′ and a measurement uncertainty of 0.05′′ (k=2). Through method comparisons, it was shown that the improved calibration method can greatly reduce calibration time and improve the calibration efficiency while ensuring the calibration accuracy, and with the decrease of measurement interval, the improvement of calibration efficiency was more obvious.
Źródło:
Metrology and Measurement Systems; 2021, 28, 1; 181-190
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simultaneous extraction of vanadium and chromium from vanadium slag using low-pressure liquid phase oxidation method
Autorzy:
Xia, J.-P.
Zheng, S.-L.
Wang, S.-N.
Liu, B.
Zou, X.
Powiązania:
https://bibliotekanauki.pl/articles/110818.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
vanadium slag
low pressure leaching
liquid phase oxidation
kinetics
Opis:
A low-pressure liquid oxidation method was proposed and proven to be effective to extract vanadium and chromium simultaneously from the vanadium slag in concentrated NaOH aqueous solutions. The effect of temperature, NaOH mass concentration, liquid-to-solid mass ratio, stirring speed and pressure on the extraction of vanadium and chromium in NaOH aqueous solutions were systematically investigated. Under the optimal reaction conditions (temperature of 473 K, liquid-to-solid mass ratio of 6:1, stirring speed of 700 rpm, NaOH mass concentration of 50%, pressure of 1 MPa and reaction time of 180 min), the vanadium and chromium recovery reached 95% and 90%, respectively. It was found that the reaction temperature and NaOH concentration were important factors for the extraction of vanadium and chromium. The kinetics of the decomposition of vanadium slag in concentrated NaOH aqueous under low pressure was analyzed using the shrinking core model, and the results indicated that the extraction of vanadium and chromium were both governed by the internal diffusion step, with apparent activation energies calculated to be 26.22 and 32.79 kJ/mol, respectively.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 2; 609-619
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Understanding the difficult selective separation characteristics of high-ash fine coal
Autorzy:
Yang, Zili
Liu, Min
Chang, Guohui
Xia, Yangchao
Li, Ming
Xing, Yaowen
Gui, Xiahui
Powiązania:
https://bibliotekanauki.pl/articles/1845210.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
high-ash fine coal
flotation
rod grinding
floatability
slime coating
Opis:
As the supply of high-quality coals decreases and mechanical coal mining becomes more widespread, the high selective recovery of high-ash fine coal has become a prominent problem in the flotation process. Herein, we discuss the main reasons why the selective separation of high-ash fine coal is difficult. The analysis of high-ash fine coal properties shows that coarse particles (0.25-0.5 mm) account for 22.53% of the total size fraction and that 57.90% of the coal is moderate- or high-density (+1.4 g/cm3) intergrowth. Grinding experiments show that the traditional rod mill has little impact on the liberation of the intergrowth. Instead, its main function is to adjust the particle size composition to ensure that the particle sizes of high-ash fine coal are within the particle size range suitable for flotation. The flotation results show that a clean coal yield of 30.42%, with a 12.46% ash content, is obtained with the optimal flotation parameters through the roughing and cleaning flotation process. However, the flotation results also show that in the separation of high-ash fine coal, it is difficult to obtain clean coal with a high yield and low ash content at the same time. This is mainly due to the similar floatability of moderate-density and low-density coal particles, which allows a large number of moderate-density coal particles to be recovered, and a significant slime coating of clay on the coal’s surface that is generated during the flotation process. The results of this work provide valuable guidance for high-ash fine coal industrial flotation applications.
Źródło:
Physicochemical Problems of Mineral Processing; 2020, 56, 5; 874-883
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Oxygen Reduction Activity of Nitrogen-doped Graphene
Autorzy:
Jian-feng, Liu
Ge, Sun
Ting, Wang
Kai, Ning
Bin-xia, Yuan
Wei-guo, Pan
Powiązania:
https://bibliotekanauki.pl/articles/2174819.pdf
Data publikacji:
2022
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
Nitrogen Doping
Graphene
Oxygen Reduction Activity
Molecular Simulation
Opis:
Graphite nitrogen, pyridine nitrogen and pyrrole nitrogen are the main nitrogen types in nitrogen-doped graphene materials. In order to investigate the mechanism of the oxygen reduction activity of nitrogen-doped graphene, several models of nitrogen-doped graphene with different nitrogen contents and different nitrogen types are developed. The nitrogen content is varied from 1.3 at% to 7.8 at%, and the adsorption energy is calculated according to the established models, then the band gaps are analyzed through the optimization results, so as to compare the mag-nitude of the conductivity. Finally, the oxygen reduction activity of graphite nitrogen-doped graphene (GNG) is found to be better than pyridine nitrogen-doped graphene (PDNG) and pyrrole nitrogen-doped graphene (PLNG) when the nitrogen content is lower than 2.6 at%, and the oxygen reduction activity of PDNG is the best when the nitrogen content was higher than 2.6 at%.
Źródło:
Polish Journal of Chemical Technology; 2022, 24, 3; 29--34
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Clinical arterial infusion of calcium gluconate: The preferred method for treating hydrofluoric acid burns of distal human limbs
Autorzy:
Zhang, Yuanhai
Ni, Liangfang
Wang, Xingang
Jiang, Ruiming
Liu, Liping
Ye, Chunjiang
Xia, Wenhao
Han, Chunmao
Powiązania:
https://bibliotekanauki.pl/articles/2178799.pdf
Data publikacji:
2014-01-01
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
Hydrofluoric Acid
burn
calcium gluconate
arterial infusion
Opis:
Objective: This study was designed to evaluate the efficiency and safety of arterial infusions of calcium gluconate to treat hydrofluoric (HF) acid burns of the distal human limbs. Materials and Methods: Eligible patients with HF burn limbs, collected from January 2008 to October 2011, were given the arterial infusion of calcium gluconate into the injured limbs. The measures of pain were conducted before the infusion, immediately after the infusion, 4 h after the infusion, and 2 days after the infusion by the visual analogy score (VAS). If the VAS score was higher than 4.0 at the time point 4 h after the first infusion, the infusion was repeated. The time of wound healing, and the number and ratio of the cases receiving the surgical operation were also evaluated. Results: A total of 118 patients, male (107 cases) and female (11 cases), were collected, including 64 cases of outpatients and 54 cases of inpatients. The age of the subjects ranged from 16 to 60 years, with the mean age of 37.6. The burn sites were located in the lateral limbs (28 cases) and in the unilateral limbs (90 cases). For 107 cases, the pain scores decreased quickly after the first infusion. The other 11 cases, with the VAS score higher than 4.0 at the time point 4 h after the first infusion, received the second infusion. The average time of wound healing and the ratio of the cases receiving the surgical operation were closely related to the interval from the injury to the reception of infusion. Conclusions: Arterial infusion of calcium gluconate, effectively relieving the pain, blocking wound progressive deepening, and causing no adverse effects, could be the preferential method to treat hydrofluoric acid burns of the distal human limbs.
Źródło:
International Journal of Occupational Medicine and Environmental Health; 2014, 27, 1; 104-113
1232-1087
1896-494X
Pojawia się w:
International Journal of Occupational Medicine and Environmental Health
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Trace muscovite dissolution separation from vein quartz by elevated temperature and pressure acid leaching using sulphuric acid and ammonia chloride solutions
Autorzy:
Lin, M.
Pei, Z.-Y.
Lei, S.-M.
Liu, Y.-Y.
Xia, Z.-J.
Xie, F.-X.
Powiązania:
https://bibliotekanauki.pl/articles/110755.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
vein quartz
muscovite
sulphuric acid
ammonium chloride
acid leaching
Opis:
Effects of sulphuric acid and ammonia chloride on muscovite dissolution were studied in acid leaching of vein quartz under elevated temperature and pressure. The leaching processes have been studied in detail by analyzing sources of impurity minerals, optimizing leaching process, analyzing leaching kinetics of Al in muscovite and charactering leaching mechanism of muscovite. The results showed that elements of Al and K mainly occurred in muscovite, and 98.10% or more of muscovite could be removed by acid leaching, while the process had limited influence on the particle size of quartz sand. Leaching of Al in the quartz ore was mainly controlled by chemical reaction. A calcination process and ammonia chloride were used for reducing chemical reaction resistance by damaging crystal structure of muscovite and providing stable acid leaching environment. Combined with the calcination process, muscovite, as a main gangue mineral, was effectively extracted during acid leaching of vein quartz at elevated temperature and pressure.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 2; 448-458
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Identification of three species commonly known as“daqingye” by internal leaf anatomy and high-performance liquid chromatography analyses
Autorzy:
Zhang, Y.
Zhu, Y.
Chen, J.
Xia, C.
Deng, J.
Li, H.
Li, Y.
Li, J.
Liu, P.
Powiązania:
https://bibliotekanauki.pl/articles/59301.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Botaniczne
Opis:
The macroscopic and microscopic morphologies and indigo and indirubin concentration of the traditional Chinese medicine herbs Isatis indigotica Fort., Polygonum tinctorium Ait., and Baphicacanthus cusia (Nees) Bremek, all commonly known as “daqingye”, were determined and compared. The morphological analyses indicated that I. indigotica has leaves with winged petioles and no glandular hairs or crystals, P. tinctorium has leaves with membranous ocrea and clusters of calcium oxalate, and B. cusia has palisade cells in the mesophyll running over the main vein and single cells containing calcium carbonate crystals. Indigo and indirubin are chemical constituents that have been previously isolated from daqingye and were selected in this study as identification markers for high-performance liquid chromatography analysis due to their pharmacological activities. The chromatographic results showed that indigo and indirubin concentration varied significantly among the three species: high concentration of both indigo and indirubin were observed in I. indigotica, the highest concentration among the three daqingye plants was found in P. tinctorium but with low levels of indirubin, and the concentration of indigo and indirubin was quite low in B. cusia. In summary, three different species commonly known as daqingye were accurately distinguished by morphological observation, internal leaf anatomy analysis, and chromatographic analysis.
Źródło:
Acta Societatis Botanicorum Poloniae; 2018, 87, 1
0001-6977
2083-9480
Pojawia się w:
Acta Societatis Botanicorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of oleic acid in different solvent media on BRL 3A cell growth and viability
Autorzy:
Liu, Runqi
Yang, Wei
Xia, Cheng
Chen, Yuanyuan
Gao, Sansi
Dong, Zhihao
Huang, Baoyin
Li, Ruirui
He, Ping
Xu, Chuang
Powiązania:
https://bibliotekanauki.pl/articles/1038377.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
oleic acid
non-alcoholic fatty liver disease
liver lipid deposition
Opis:
Oleic acid (OA) is widely used in pathology studies of hepatocellular lipid deposition. Identifying the effects of different solvents on OA-induced liver lipid deposition would be beneficial for studies on hepatocytes. We treated BRL 3A cells with OA dissolved in different solvents. After 12 h incubation, cell viability was assessed using MTT assays. Reactive oxygen species (ROS), triglyceride (TG) and total cholesterol (TC) counts, and the expression level of glucose regulated protein (GRP78), sterol regulatory element binding protein (SREBP-1C) and fatty acid synthase (FAS) were analyzed. Water, PBS and DMSO were disadvantageous to the dissolution of OA and did not cause an OA-induced response in hepatocytes. In the alcohol+OA-treated cells, the severe ER stress, oxidative stress and cellular fat deposition were significantly increased. BSA promoted cell growth and the cells treated with 1.2% BSA+OA showed a lower grade TG and endoplasmic reticulum stress compared with KOH+OA and alcohol+OA treatments. KOH had no significant influence on BRL 3A cells viability. When treated with OA dissolved in KOH, BRL 3A cells showed a typical hepatocyte damage. KOH was considered the suitable choice for an OA solvent for BRL 3A cells in hepatic lipidosis research.
Źródło:
Acta Biochimica Polonica; 2018, 65, 3; 443-447
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The relationship between manganism and the workplace environment in China
Autorzy:
Wang, Yongyi
Xue, Jian
Cheng, Shuqun
Ding, Yubin
He, Junlin
Liu, Xueqing
Chen, Xuemei
Wang, Yingxiong
Feng, Xiangyu
Xia, Yinyin
Powiązania:
https://bibliotekanauki.pl/articles/2180079.pdf
Data publikacji:
2012-09-01
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
manganese
occupational exposure
welding
mining
occupational intoxication
chronic manganism
Opis:
Manganese is a trace element and a cofactor of many enzymes, so it is essential for physiologic functioning, but it is also a neurotoxin at high doses. Manganism is most often caused by occupational exposure. It is manifested by a myriad of signs and symptoms ranging from the neurasthenia syndrome, such as headache and dizziness, to the Parkinson-like syndrome, depending on the blood manganese levels as well as the duration of exposure. We are reporting a case of manganism using both clinical and occupational hygiene investigation methods. The patient presented the neurasthenia syndrome accompanied by hypertonicity of arm muscles and was diagnosed to have mild chronic manganism. Finally, the patient was discharged from the hospital after the treatment had improved her condition. In China, there are many chronic manga nese cases, partly due to a rapid industrial development with great use of Mn and the low self-protection awareness among the workers and the factories management that cannot catch up with the speed of the economical development. Therefore, factories are responsible for improving the conditions at the workplace.
Źródło:
International Journal of Occupational Medicine and Environmental Health; 2012, 25, 4; 501-505
1232-1087
1896-494X
Pojawia się w:
International Journal of Occupational Medicine and Environmental Health
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of differential serum expression of three factors and pulmonary function in patients with silicosis
Autorzy:
Zhu, Ying
Duan, Xia Yu
Cheng, Yun Qi
Yao, Xin Jing
Xu, Hong
Zhang, Kui Sheng
Li, Feng Shi
Yang, Fang
Liu, Liang He
Yuan, Xiang Ju
Powiązania:
https://bibliotekanauki.pl/articles/2086531.pdf
Data publikacji:
2021-08-05
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
silicosis
pulmonary function
early diagnosis
ROC
PTPN2
factor B
Opis:
ObjectivesSilicosis is a chronic occupational lung disease. As was previously found by the authors, some proteins increased in the lung tissue of activated rats, and protein tyrosine phosphatase non-receptor type 2 (PTPN2), factor B, and vaccinia-related kinase 1 (VRK1) showed highly differential expressions.Material and MethodsIn this study, serum and bronchoalveolar lavage fluid samples were collected from patients with silicosis and healthy people to verify the expression of PTPN2, factor B, and VRK1. The diagnostic value of differentially expressed proteins for silicosis was judged.ResultsThe expression levels of serum PTPN2, VRK1, and factor B in patients with silicosis were significantly higher than those in the control group (p < 0.01). Higher serum PTPN2 and factor B concentrations significantly and negatively correlated with the ratio of forced expiratory volume in 1 s to forced vital capacity (FEV1/FVC), maximum vital capacity (VCmax), FEV1, and FVC, suggesting that the high expression of PTPN2 and factor B is associated with decreased pulmonary ventilation function and restrictive ventilatory impairment in patients with silicosis. All area under curve (AUC) measurements generated from single detection events were >0.744, with PTPN2 reaching the highest value (0.858). The AUC, sensitivity, and specificity for the combined diagnosis using factor B and PTPN2 were 0.907, 86.91% and 85.07%, respectively, for factor B and PTPN2. The 3 differentially expressed proteins are potential classes of predictive biomarkers for silicosis.ConclusionsRegarding the economy and test practicality, the best diagnostic combination is factor B and PTPN2 for the analysis of AUC, sensitivity and specificity.
Źródło:
International Journal of Occupational Medicine and Environmental Health; 2021, 34, 4; 527-540
1232-1087
1896-494X
Pojawia się w:
International Journal of Occupational Medicine and Environmental Health
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Correlation of chromosome damage and promoter methylation status of the DNA repair genes MGMT and hMLH1 in Chinese vinyl chloride monomer (VCM)-exposed workers
Autorzy:
Wu, Fen
Liu, Jing
Qiu, Yu-Lan
Wang, Wei
Zhu, Shou-Min
Sun, Pin
Miao, Wen-Bin
Li, Yong-Liang
Brandt-Rauf, Paul W.
Xia, Zhao-Lin
Powiązania:
https://bibliotekanauki.pl/articles/2179802.pdf
Data publikacji:
2013-03-01
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
vinyl chloride monomer
chromosome damage
MGMT
hMLH1
DNA methylation
Opis:
Objective: To explore the association of the methylation status of MGMT and hMLH1 with chromosome damage induced by vinyl chloride monomer (VCM). Materials and Methods: Methylation of MGMT and hMLH1 was measured in 101 VCM-exposed workers by methylation-specifi c PCR. Chromosome damage in peripheral blood lymphocytes was measured by the cytokinesis-block micronucleus assay. The subjects were divided into chromosome damaged and non-damaged groups based on the normal reference value of micronuclei frequencies determined for two control groups. Results: MGMT promoter methylation was detectable in 5 out of 49 chromosome damaged subjects, but not in the chromosome non-damaged subjects; there was a signifi cant difference in MGMT methylation between the two groups (p < 0.05). Conclusions: We detected aberrant promoter methylation of MGMT in a small number of chromosome damaged VCM-exposed workers, but not in the chromosome non-damaged subjects. This preliminary observation warrants further investigation in a larger study.
Źródło:
International Journal of Occupational Medicine and Environmental Health; 2013, 26, 1; 173-182
1232-1087
1896-494X
Pojawia się w:
International Journal of Occupational Medicine and Environmental Health
Dostawca treści:
Biblioteka Nauki
Artykuł
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