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Wyświetlanie 1-13 z 13
Tytuł:
Wideband optical frequency comb generation using a fiber re-circulating loop cascaded with a spectrum expander including highly nonlinear fiber
Autorzy:
Wang, F.
Kang, W.
Powiązania:
https://bibliotekanauki.pl/articles/1835772.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
optical frequency comb
highly nonlinear fibre
cascaded four-wave mixing
Opis:
A wideband optical frequency comb (OFC) generator using a fiber re-circulating loop (FRL) including a phase modulator and optical amplifier, cascaded with a spectrum expander containing a high-power erbium-doped fiber amplifier and highly nonlinear fiber (HNLF) is proposed and experimentally demonstrated, in which the FRL is used as a source to generate seed comb lines, and then generated seed comb lines are extended to a wideband optical frequency comb using cascaded four-wave mixing in the HNLF. Only using one stage spectrum expander, a stable 20-GHz optical comb with 201 comb lines within 30-dB power deviation, spanning 40-nm bandwidth, is achieved. The results show that the HNLF has unique ability to broaden output spectrum from the FRL. In addition, an optical frequency comb is dramatically broadened, which may be predicted by optimizing gain and dispersion of the FRL or configuration of the spectrum expander, or both.
Źródło:
Optica Applicata; 2021, 51, 2; 181-191
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transmission characteristics of 85Rb and 87Rb laser-induced dichroism atomic filters at 795 nm
Autorzy:
Peng, Y F
Zhang, W J
Powiązania:
https://bibliotekanauki.pl/articles/173843.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
atomic filter
optical anisotropy
narrowband
rubidium
Opis:
The transmission characteristics for 85Rb and 87Rb laser-induced dichroism atomic filters operating on rubidium D1 lines (795 nm) transitions are analyzed. By means of semiclassical density matrix equations of motion, a three-level model for the transmission characteristics of the ground state laser-induced dichroism atomic filter is presented. Calculative results show that this filter, using two counterpropagating pump and probe beams, can obtain higher transmission, narrower bandwidth and larger tuning capability than that using two copropagating pump and probe beams; with the aid of counterpropagating pump, the 85Rb ground state laser-induced dichroism atomic filter can be more effective to achieve higher peak transmission (>34%) and larger tunability (>1 GHz) than the 87Rb ground state laser-induced dichroism atomic filter in the same operation parameters. This result may be helpful for improving peak transmission (14.6%) of Rb ground state laser-induced dichroism atomic filter reported (CERÈ A. et al., Opt. Lett. 34(7), 2009, pp. 1012–1014).
Źródło:
Optica Applicata; 2014, 44, 1; 55-67
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effectiveness of spheroidization pearlitic steel with regard to the degree of plastic deformation
Autorzy:
Grygiel, D.
Dudziński, W,
Gerstein, G.
Nürnberger, F.
Powiązania:
https://bibliotekanauki.pl/articles/1190029.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
stal perlityczna
wyżarzanie
cementyt
pearlitic steel
annealing
cementite
Opis:
Pearlitic steels containing from some 0,8 to 0,95% C belong to the group of unalloyed steels of the quality class destined for cold drawing or rolling, they find application mainly as wires used for reinforcement of tires, hoses or rope production. However this group of steels characterized low machinability, as a consequence of presence hard plates of cementite, the intervention ameliorative this property is spheroidizing annealing. The object of the tests presented in paper was wires of pearlitic steel obtained after the successive stages of cold plastic working. The aim of the tests was to show that the condition of the material and mainly degree of plastic deformation have a clearly influence on the effectiveness of pearlitic steel spheroidization.
Źródło:
Interdisciplinary Journal of Engineering Sciences; 2015, 3, 1; 6--9
2300-5874
Pojawia się w:
Interdisciplinary Journal of Engineering Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An innovative technology for recovery of zinc, lead and silver from zinc leaching residue
Autorzy:
Zheng, Y.-X.
Lv, J.-F.
Liu, W.
Qin, W.-Q.
Wen, S.-M.
Powiązania:
https://bibliotekanauki.pl/articles/110688.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
zinc leaching residue
lead sulfate
zinc sulfate
reduction roasting
flotation
Opis:
Zinc leaching residue is a good source of zinc and has a great potential to be utilized. However, it is very difficult to recover lead, zinc and silver from the residue by traditional technologies. In this study, a new technology based on conversions of PbSO4 and ZnSO4 in the residue to their respective sulfides by reduction roasting with coal powder followed by a flotation treatment was developed. The effects of roasting temperature, coal dosage, reaction time and pyrite dosage were investigated at a laboratory scale. The results showed that the conversion extent of PbSO4 and ZnSO4 under the optimal experimental conditions was 71.89 and 69.76%, respectively. A flotation concentrate containing 39.13% Zn, 6.93% Pb and 973.54 g/Mg Ag was obtained from the treated material, and the recovery of Zn, Pb and Ag was 48.38, 68.23 and 77.41%, respectively. The tailing containing ZnFe2O4 or Fe3O4 could be either stockpiled or further disposed.
Źródło:
Physicochemical Problems of Mineral Processing; 2016, 52, 2; 943-954
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Drilling resistance : A method to investigate bone quality
Autorzy:
Lughmani, W. A.
Farukh, F.
Bouazza-Marouf, K.
Ali, H.
Powiązania:
https://bibliotekanauki.pl/articles/306405.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
chirurgia ortopedyczna
wiercenie
gęstość mineralna kości
jakość kości
bone drilling
orthopaedic surgery
screw pull-out strength
bone mineral density
bone quality
Opis:
Purpose: Bone drilling is a major part of orthopaedic surgery performed during the internal fixation of fractured bones. At present, information related to drilling force, drilling torque, rate of drill-bit penetration and drill-bit rotational speed is not available to orthopaedic surgeons, clinicians and researchers as bone drilling is performed manually. Methods: This study demonstrates that bone drilling force data if recorded in-vivo, during the repair of bone fractures, can provide information about the quality of the bone. To understand the variability and anisotropic behaviour of cortical bone tissue, specimens cut from three anatomic positions of pig and bovine were investigated at the same drilling speed and feed rate. Results: The experimental results showed that the drilling force does not only vary from one animal bone to another, but also vary within the same bone due to its changing microstructure. Drilling force does not give a direct indication of bone quality; therefore it has been correlated with screw pull-out force to provide a realistic estimation of the bone quality. A significantly high value of correlation (r 2 = 0.93 for pig bones and r 2 = 0.88 for bovine bones) between maximum drilling force and normalised screw pull-out strength was found. Conclusions: The results show that drilling data can be used to indicate bone quality during orthopaedic surgery.
Źródło:
Acta of Bioengineering and Biomechanics; 2017, 19, 1; 55-62
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Converged ultra-wideband and multi-level wired signal downstream transport over single wavelength in wavelength-division multiplexing passive optical network
Autorzy:
Ma, H
Wang, F.
Wang, W.
Zhang, X
Yu, Q.
Powiązania:
https://bibliotekanauki.pl/articles/174929.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
ultra-wideband (UWB)
multi-level amplitude switch keying (M-ASK)
wavelength-division multiplexing passive optical network (WDM-PON)
Opis:
Simultaneous providing services of ultra-wideband and wired signal over single wavelength can greatly decrease the complexity and reduce the costs of a wavelength-division multiplexing passive optical network. However, ultra-wideband signal occupies the spectrum range from 3.1 to 10.6 GHz, and a narrow idle frequency band (from 0 to 3.1 GHz) could be employed to transport wired signal with a limited rate. In this paper, we proposed a scheme to simultaneously provide ultra-wideband and wired services, in which the information rate of the wired signal is enhanced by employing a multi-level amplitude switch keying signal in the idle frequency band formed by ultra-wideband signal. In comparison with other advanced modulation formats used for wavelength-division multiplexing passive optical networks such as orthogonal frequency division multiplexing, multi-level amplitude switch keying signal can be easily received by using intensity modulation direct detection, which will greatly reduce the cost of end-users. Especially, if a multi-band ultra-wideband signal is substituted for the direct-sequence ultra-wideband signal, the available spectrum range to transport wired signal will be easily extended to 5 GHz as multi-band ultra-wideband signal has a narrower spectrum width and flexible center frequency, so 4-amplitude switch keying signal with a rate of 5 Gbaud will achieve an information rate of 10 Gbit/s.
Źródło:
Optica Applicata; 2015, 45, 4; 433-445
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Potato waste treatment by microbial fuel cell. Evaluation based on electricity generation, organic matter removal and microbial structure
Autorzy:
Du, H.
Li, F.
Huang, K.
Li, W.
Feng, C.
Powiązania:
https://bibliotekanauki.pl/articles/206898.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
water treatment
performance
technology
bacterial
recovery
sludge
carbon
microbial fuel cell
COD
potato waste
uzdatnianie wody
ChZT
węgiel
odpady ziemniaczane
Opis:
The performance of microbial fuel cell (MFC) in treating potato waste was evaluated using a two-chamber MFC supplied with potato liquid after mastication of market available fresh potato. Evaluation was conducted based on electricity generation, organic matter removal (CODCr, DOC and volatile fatty acids (VFAs)), and microbial structure on the anode and in the anodic solution of the reactor. Current density exhibited a trend that followed the concentration changes of organic matter in the solution, with its highest value being observed as 208 mA/m2. Effective removal of organic matter was also observed. By the end of the experiment, the removal for total COD reached about 84%. Bacterial structure analysis based on PCR, DGGE and sequencing indicated that more species were developed in the anodic solution than on the anode, with Proteobacteria, Firmicutes and Bacteroides being dominant. Geobacter, a well reported exoelectrogenic species, was found more predominant on the anode than in the anodic solution. The results thus indicated that simultaneous stabilization and electricity generation could be achieved when potato waste is treated in MFC.
Źródło:
Environment Protection Engineering; 2017, 43, 1; 5-18
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Enhancing SO2 removal efficiency by lime modified with sewage sludge in a novel integrated desulfurization process
Autorzy:
Qin, L.
Han, J.
Chen, W.
Liu, Z.
He, M.
Xing, F.
Powiązania:
https://bibliotekanauki.pl/articles/950037.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
sewage sludge
steel industry
sintering process
osad ściekowy
przemysł hutniczy
proces spiekania
Opis:
In China, the sintering process annually emitted around 1.5 million t SO2, representing 70% of SO2 produced from the iron and steel industry. Lime based sorbent was modified with municipal sewage sludge (MSS) and the influence of the modification on the desulfurization efficiency was investigated in a laboratory-scale novel integrated desulfurization (NID) reactor. The properties of modified sorbent were characterized by the Brunauer–Emmett–Teller (BET) analyzer and X-ray fluorescence (XRD) analyzer. BET surface area was increased from 17.48 to 46.68 m2g–1. when the MSS/lime ratio increased from 0 to 0.08. Ca4Al8Si8O32, Ca1.5SiO3.5, Na2Si2O5 and CaSiO3 found in the modified lime benefited for the increase of the BET surface area and pore volume. The effects of sewage sludge/CaO weight ratio, calcination temperature and hydration time on the desulfurization efficiency were also studied. SO2 removal efficiency was increased from 88.7% to 97.3% after using the lime modified with sewage sludge.
Źródło:
Environment Protection Engineering; 2017, 43, 4; 17-27
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fast and effective extraction for equivalent shunt resistances of triple-junction concentrator solar cells
Autorzy:
Lv, H
Dai, J
Sheng, F
Liu, W
Ma, X
Cheng, C
Lv, Q
Powiązania:
https://bibliotekanauki.pl/articles/174425.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
concentrator photovoltaic
triple junction solar cell
equivalent shunt resistance
Opis:
Fast and effective extraction of equivalent shunt resistance for each subcell of GaInP/GaInAs/Ge triple-junction concentrator solar cells is presented. The two-diode model of single junction was introduced to establish the equivalent circuit of triple-junction solar cells. The current-voltage characteristic of the triple-junction solar cells was measured under AM1.5D spectrum, C = 576 and T = 303 K. Equivalent shunt resistance of each subcell was extracted from its estimated current-voltage curve. The estimated current-voltage curve of the triple-junction solar cells shows a good agreement with the experimental data in 0.31% deviation. The degradation in the equivalent shunt resistance for Ge subcell was intentionally introduced to indicate the mechanism of current-matching operation for different subcells, with the maximum output power of the triple-junction solar cells deteriorating from 3.5 to 3.17 W. The results can offer performance analysis and optimum design of photovoltaic applications.
Źródło:
Optica Applicata; 2015, 45, 2; 227-235
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Use of nanofiltration membranes to concentrate and recover leached aluminum from acidified water treatment sludge
Autorzy:
Cheng, W. P.
Chen, P. H.
Tian, D. R.
Yu, R. F.
Fu, C. H.
Powiązania:
https://bibliotekanauki.pl/articles/208030.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
water purification
nanofiltration
acidic solutions
leaching
roztwory kwaśne
oczyszczanie wody
nanofiltracja
ługowanie
glin
Opis:
The recovery of aluminum from water purification sludge is usually performed by making the solution acidic or basic. However, for economic reasons and reasons of safety, excessive doses of acid or base should not be utilized. Accordingly, the aluminum concentration in the leached solution is typically limited, thus the recovered aluminum cannot be directly reused as a coagulant. A nanofiltration (NF) membrane can be used in the acidic solution to concentrate high-valence metal ions. There-fore, in this work, H2SO4 was utilized to leach Al3+ ions from water purification sludge. Then, the Al3+ ion solution was concentrated using a low-price NF membrane. The effect of natural organic matter on the Al3+ ion concentrating efficiency in the filtration process has been elucidated. Experimental results reveal that Al3+ ions were effectively prevented from passing through the NF membrane, enabling a highly concentrated aluminum solution to be obtained. However, the presence of organic compounds may reduce the efficiency of the concentration of Al3+ ions in the solution.
Źródło:
Environment Protection Engineering; 2016, 42, 3; 19-32
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Assessing soil environmental capacity on different land uses in a suburban area of Chengdu, China
Autorzy:
Yang, W.-L.
Zhou, W.-Y.
Wan, W.-X.
Gou, S.-Z.
Zhang, J.
Deng, S.-H.
Shen, F.
Wang, Y.-J.
Yang, H.
Luo, L.
Powiązania:
https://bibliotekanauki.pl/articles/207670.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
China
soil pollution
heavy metals
soil
vegetables
Chiny
zanieczyszczenie gleby
metale ciężkie
gleba
warzywa
Opis:
Wenjiang (China) is the area which undertakes high-intensity planting activities. Additionally, the soil environmental capacity has been a hot area of research as it plays a key role in environmental protection planning, environmental impact assessment and sustainable development. In this paper, the static model of soil environmental capacity is employed to investigate the distribution of residual soil environmental capacity in Wenjiang. The results show that the soil environmental capacity of mercury is the largest for industrial land while it is the lowest in garlic-rice planting areas; the soil environmental capacity of arsenic is the largest in city construction land while it is the lowest in ecological conservation zone; the soil environmental capacity of lead is the largest in city construction land while it is the lowest in garlic-rice planting areas; and the soil environmental capacity of chromium is the largest in city construction land while it is the lowest in garlic-rice planting areas.
Źródło:
Environment Protection Engineering; 2019, 45, 2; 55-67
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A longitudinal assessment of myoelectric activity, postural sway, and low-back pain during pregnancy
Autorzy:
Moreira, L. S.
Elias, L. A.
Gomide, A. B.
Vieira, M. F.
Do Amaral, W. N.
Powiązania:
https://bibliotekanauki.pl/articles/307463.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
elektromiografia
stabilność postawy
bóle kręgosłupa
electromyography
low back pain
postural balance
pregnancy trimesters
stabilometry
Opis:
The present study aimed at investigating the control of upright quiet standing in pregnant women throughout pregnancy, and whether low-back pain exerts influence on this motor task. Methods: Myoelectric signals from postural muscles and stabilometric data were collected from 15 non-pregnant and 15 pregnant women during upright quiet standing. Electromyogram envelopes and center of pressure metrics were evaluated in the control group, as well as in pregnant women in their first and third trimester of pregnancy. A correlation analysis was performed between the measured variables and a low-back pain disability index. Results: Pregnant women exhibited a decreased maximum voluntary isometric activity for all postural muscles evaluated. Additionally, the activity of lumbar muscles during the postural task was significantly higher in the pregnant women in comparison to the non-pregnant controls. The soleus muscle maintained its activity at the same level as the gestation progressed. Higher postural oscillations were observed in the anteroposterior direction while mediolateral sway was reduced in the third trimester of pregnancy. No correlation was detected between the lowback pain disability index and neuromechanical variables. Conclusion: This study provides additional data regarding the functioning and adaptations of the postural control system during pregnancy. Also, we provide further evidence that postural control during quiet standing cannot be used to predict the occurrence of low-back pain. We hypothesize that the modifications in the neural drive to the muscles, as well as in postural sway may be related to changes in the biomechanics and hormonal levels experienced by the pregnant women.
Źródło:
Acta of Bioengineering and Biomechanics; 2017, 19, 3; 77-83
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of float-sink and progressive release flotation of ground products of coal middlings
Autorzy:
Xie, W.
He, Y.
Luo, C.
Zhang, X.
Li, H.
Yu, J.
Wang, H.
Shi, F.
Powiązania:
https://bibliotekanauki.pl/articles/109500.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
coal middlings
float-sink
progressive release flotation
XPS
EDX
Opis:
An additional recovery of coking coal middlings can be utilized for increasing of the concentrate yield of coking coal. A combined flow sheet of comminution and flotation can realize this target. To investigate the effect of grinding process on further flotation of ground products, progressive release flotation tests were used to compare with the float-sink tests, which were regarded as a criterion. Coal middlings were ground by wet-milling with iron balls to <0.5 mm. Curves of ash vs. cumulative yields of sized products indicated that the concentrate yield of coal separated by progressive release flotation was lower than that of coal benefited by the float-sink test, with the same ash for four size fractions (0.5-0.25 mm, 0.25-0.125 mm, 0.125-0.074 mm and <0.074 mm). Distributions of elements conducted by energy disperse spectroscopy (EDX) showed that associated kaolinite was liberated and exposed on the surface. It led to the shift of local surface property from hydrophobicity to hydrophilicity. Meanwhile, analyses of chemical property performed by an X-Ray photoelectron spectrometer (XPS) depicted that the hydrophilic mineral FeOOH, which generated in the grinding process, was adsorbed on the coal surface. Flotation of the ground products were worsened due to the increase of hydrophilicity of the coal surface.
Źródło:
Physicochemical Problems of Mineral Processing; 2015, 51, 2; 675-684
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-13 z 13

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