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Wyszukujesz frazę "Han, Jun" wg kryterium: Autor


Wyświetlanie 1-8 z 8
Tytuł:
Point-ahead analysis and pre-pointing link stability study of intersatellite laser communication
Autorzy:
Zhang, Fu-Rui
Han, Jun-Feng
Ruan, Ping
Powiązania:
https://bibliotekanauki.pl/articles/174817.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
intersatellite laser communication
point-ahead
link stability
simulation
Opis:
The static bias error angle obviously affects pre-pointing links’ stability in the presence of vibration in intersatellite laser communication. The 2nd order point-ahead angle is a source of misalignment which was ignored in most solutions, and this is the concern of our paper. In this study, we present a further analytical investigation into the point-ahead angle in complex satellite maneuvering environment. Static bias error angle induced by the 2nd order point-ahead angle has been studied under different intersatellite links. The probability density function of the pre-pointing links’ outage has been derived in the presence of pointing jitter taking consideration of the static bias angle, and the link budget has also been analyzed. Simulation model of link stability has been established to verify the numerical results by the Monte Carlo method in Matlab-Simulink environment. The results have shown that the 2nd order point-ahead angle has a significant detrimental impact on link stability in long distance links. It is a neglectable factor. This work is dedicated to intersatellite laser communication system design.
Źródło:
Optica Applicata; 2020, 50, 1; 111-126
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Overburden failure and ground pressure behaviour of longwall top coal caving in hard multi-layered roof
Zawał warstw nadkładu w wielowarstwowym stropie i kształtowanie się ciśnienia warstw górnych górotworu w trakcie wybierania ścianowego prowadzonego na zawał
Autorzy:
Zhu, Zhijie
Wu, Yunlong
Han, Jun
Chen, Ying
Powiązania:
https://bibliotekanauki.pl/articles/219625.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
strop złożony z wielu warstw skał twardych
zawał warstw nadkładu
zmiany ciśnienia gruntu
zawał stropu skały węglowej w rejonie przodka
multi-layer hard roof
failure of overlying strata
ground pressure behaviour
longwall top coal caving
Opis:
In the extra- thick coal seams and multi-layered hard roofs, the longwall hydraulic support yielding, coal face spalling, strong deformations of goaf-side entry, and severe ground pressure dynamic events typically occur at the longwall top coal caving longwall faces. Based on the Key strata theory an over-burden caving model is proposed here to predict the multilayered hard strata behaviour. The proposed model together with the measured stress changes in coal seam and underground observations in Tongxin coal mine provides a new idea to analyse stress changes in coal and help to minimise rock bursts in the multi-layered hard rock ground. Using the proposed primary Key and the sub-Key strata units the model predicts the formation and instability of the overlying strata that leads to abrupt dynamic changes to the surrounding rock stress. The data obtained from the vertical stress monitoring in the 38 m wide coal pillar located adjacent to the longwall face indicates that the Key strata layers have a significant influence on ground behaviour. Sudden dynamically driven unloading of strata was caused by the first caving of the sub-Key strata while reloading of the vertical stress occurred when the goaf overhang of the sub-Key strata failed. Based on this findings several measures were recommended to minimise the undesirable dynamic occurrences including pre-split of the hard Key strata by blasting and using the energy consumption yielding reinforcement to support the damage prone gate road areas. Use of the numerical modelling simulations was suggested to improve the key theory accuracy.
Przy eksploatacji pokładów węgla o dużej miąższości i w warunkach stropu złożonego z wielu warstw górotworu w rejonie przodka ściany występuje szereg niekorzystnych zjawisk dynamicznych skutkujących zmianami ciśnienia górotworu: ugięcie podpór hydraulicznych stabilizujących strop, pękanie skały węglowej w rejonie przodka, silne odkształcenia chodnika od strony zrobów. W oparciu o teorię warstwy kluczowej (o największej nośności), zaproponowano model zawału warstwy nadkładu do prognozowania zachowania wielowarstwowej formacji złożonej ze skał twardych. Zaproponowany model w połączeniu z pomiarami zmian ciśnienia w pokładzie węgla oraz wynikami obserwacji w podziemnej kopalni węgla Tongxin umożliwia analizę zmian ciśnienia w złożu przyczyniając się do redukcji ryzyka wystąpienia tąpnięć w górotworze zbudowanym z wielu warstw skalnych. Uwzględniając charakterystyki podstawowych warstw kluczowych, model umożliwia prognozowanie wystąpienia niestabilności warstw nadkładu, które prowadzić mogą do gwałtownych zmian ciśnienia w otaczających warstwach. Dane z monitoringu naprężeń pionowych rejestrowane w filarze węglowym o szerokości 38 m zlokalizowanym w pobliżu przodka ściany wskazują, że warstwy kluczowe górotworu w zasadniczy sposób warunkują zachowanie się gruntu. Gwałtowne odprężenie warstw górotworu wskutek zjawisk dynamicznych spowodowane zawałem warstwy znajdującej się poniżej warstwy kluczowej przy ponownym obciążeniu wskutek naprężeń pionowych wystąpiło w momencie zawału nawisu górnej ławy warstwy znajdującej się poniżej warstwy kluczowej. W oparciu o te ustalenia, zaproponowano szereg rozwiązań mających na celu zminimalizowanie skutków niekorzystnych zjawisk dynamicznych, w tym wstępne rozszczepienie twardych warstw kluczowych poprzez wybuchy i zabezpieczenie obudową wejść do chodników, które mogłyby ulec uszkodzeniu. Zaproponowano wykorzystanie modelu wraz z symulacjami numerycznymi w celu poprawy dokładności teorii dotyczącej zachowania warstw kluczowych w górotworze.
Źródło:
Archives of Mining Sciences; 2019, 64, 3; 575-590
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Master Curve Model for Characterization of Decomposition and Densification Behavior of PbAlNbO3-PbZrTiO3 Ceramics
Autorzy:
Han, Jun Sae
Park, Jae Man
Park, Seong Jin
Powiązania:
https://bibliotekanauki.pl/articles/355280.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
master debinding curve
master sintering curve
PAN-PZT
powder injection molding
dilatometer
Opis:
In this study, decomposition and densification behavior of PbAlNbO3-PbZrTiO3 (PAN-PZT) ceramics were characterized for powder injection molding process. Thermal gravity analysis and in-situ dilatometer experiment were carried out to construct master curve. Based on master curve model approach, one-combined master debinding curve (MDC) and master sintering curve (MSC) were constructed for piezoelectric PAN-PZT ceramics. Derived curves matched well with the experimental data. Process optimization and material development will be conducted based on characterization of master curve parameters.
Źródło:
Archives of Metallurgy and Materials; 2020, 65, 3; 1099-1103
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Gas6 gene rs8191974 and Ap3s2 gene rs2028299 are associated with type 2 diabetes in the northern Chinese Han population
Autorzy:
Kazakova, Elena
Zghuang, Tianwei
Li, Tingting
Fang, Qingxiao
Han, Jun
Qiao, Hong
Powiązania:
https://bibliotekanauki.pl/articles/1038636.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
Type 2 diabetes mellitus
Gas6 gene
Ap3s2 gene
single nucleotide polymorphisms
epidermal growth factor (EGF)-like
Opis:
Previous studies in other countries have shown that single nucleotide polymorphisms (SNPs) in the growth arrest-specific gene 6 (Gas6; rs8191974) and adapter-related protein complex 3 subunit sigma-2 (Ap3s2; rs2028299) were associated with an increasedrisk for type 2 diabetes mellitus (T2DM). However, the association of these loci with T2DM has not been examined in Chinese populations. We performed a replication study to investigate the association of these susceptibility loci with T2DM in the Chinese population.We genotyped 1968 Chinese participants (996 with T2DM and 972controls) for rs8191974 in Gas6 and rs2028299 near Ap3s2, and examined their association with T2DM using a logistic regression analysis. We also analyzed the correlation of genotypes and clinical phenotypes. The distribution of the T allele of SNP rs8191974 in the Gas6 gene was significantly different between T2DM cases and controls when compared with the C allele (P<0.05, OR: 0.80, 95% CI: 0.69-0.94). The occurrence of the CT genotype and the dominant model was also significantly less frequent in the T2DM cases vs. controls when compared with the CC genotype (CT vs. CC: P<0.05, OR: 0.75, 95% CI:0.62-0.90; TT+CT vs. CC: P<0.05, OR:0.75, 95% CI:0.63-0.90). In SNP rs2028299, the allele C showed no statistically significant differencein distribution between the control and T2DM groups when compared with allele A. However, in male populations, the dominant model was statistically more frequent when compared with genotype AA (CC+CA vs. AA: P<0.05, OR:1.29, 95% CI:1.02-1.64), and in obesity-stratified analysis, we also observed a significant difference in the distribution of the dominant model between the T2DM cases and controls in subjects with BMI≥24 kg/m2 and BMI<28kg/m2 (CC+CA vs. AA: P<0.05, OR: 6.33, 95% CI:4.17-9.61). In conclusion, our study shows that SNPsrs8191974 and rs2028299 are significantly associated with T2DM in the Chinese population.
Źródło:
Acta Biochimica Polonica; 2017, 64, 2; 227-231
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The prevalence and risk factors of musculoskeletal disorders in the hands of fishermen working as oyster shuckers
Autorzy:
Park, Jin Sung
Yoo, Jun-Il
Na, Jae-Bum
Song, Han Soo
Powiązania:
https://bibliotekanauki.pl/articles/2095509.pdf
Data publikacji:
2021-09-03
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
osteoarthritis
fishermen
musculoskeletal disorders
wrist
hands
oyster shuckers
Opis:
ObjectivesThis study aimed to investigate the prevalence of musculoskeletal disorders in the hands and wrists of fishermen working as oyster shuckers, and to identify the risk factors associated with oyster shucking. Material and Methods A total of 590 fishery workers including those working as oyster shuckers in 2015–2017 were included in the study analysis. Hand osteoarthritis (OA), carpal tunnel syndrome (CTS), and ulnar impaction syndrome were diagnosed using X-ray, magnetic resonance imaging, and physical examinations according to each diagnostic criterion. The Rapid Entire Body Assessment was used as a measurement tool for analyzing the occupation-related burden factors.ResultsThe prevalence of hand OA, CTS, and ulnar impaction syndrome was higher in oyster shuckers than in aquaculture/offshore fishery workers. The prevalence of upper limb disease was higher in oyster shuckers than in other fishery workers, even in the prevalence of exposure to occupational burden factors. In oyster shuckers, the incidence of hand and wrist OA was 84%, that of CTS was 72%, and that of ulnar impaction syndrome was 41%. In addition, oyster shuckers were more likely to be exposed to occupational burden factors than were other types of fishermen. Conclusions The prevalence of hand OA, CTS, and ulnar impaction syndrome was higher in oyster shuckers. Therefore, proper stretching or exercises for rest and musculoskeletal relaxation, along with health-care education and promotion, will be needed for the fishermen’s repeated posture and impact work.
Źródło:
International Journal of Occupational Medicine and Environmental Health; 2021, 34, 5; 603-615
1232-1087
1896-494X
Pojawia się w:
International Journal of Occupational Medicine and Environmental Health
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Vibration transients of reservoir-pipe-valve system caused by water hammer
Autorzy:
Miao, Yang
Jiang, Yuncheng
Qiu, Zaihui
Pan, Jun
Wang, Lu
Han, Zhenrong
Li, Kun
Zhang, Li
Zhang, Xiaolu
Powiązania:
https://bibliotekanauki.pl/articles/1839616.pdf
Data publikacji:
2020
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
reservoir-pipe-valve system (RPV system)
water hammer
vibration
transients
Opis:
A severe oscillation, accompanied with an abnormal “click” sound, of a fuel feeding pipe system during valve closing, when the feeding flowrate reaches a certain value, is observed experimentally. A fluctuation model in which stiffness and damping coefficients of the vibration system are time varying is proposed. Each coefficient is composed of two parts, one of which is constant and the other is time varying. Based on this model, simulation transients of the vibration displacement, velocity and pressure in the pipe are presented. Simulations of the pressure transients are compared with experimental data detected by pressure transducer, which shows that both have fluctuations in the transient process at a large flowrate.
Źródło:
Journal of Theoretical and Applied Mechanics; 2020, 58, 4; 1037-1048
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design and performance of dual-band MWIR/LWIR focal plane arrays based on a type-II superlattice nBn structure
Autorzy:
Lee, Hyun-Jin
Eom, Jun Ho
Jung, Hyun Chul
Kang, Ko-Ku
Ryu, Seong Min
Jang, Ahreum
Kim, Jong Gi
Kim, Young Ho
Jung, Han
Kim, Sun Ho
Choi, Jong Hwa
Powiązania:
https://bibliotekanauki.pl/articles/2204217.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
InAs/GaSb type-II superlattice
dualband detector
dark current
spectral quantum efficiency
noise equivalent temperature difference
Opis:
Dual-band infrared detector, which acquires more image information than single-band detectors, has excellent detection, recognition, and identification capabilities. The dual-band detector can have two bumps to connect with each absorber layer, but it is difficult to implement small pitch focal plane arrays and its fabrication process is complicated. Therefore, the most effective way for a dual-band detector is to acquire each band by biasselectable with one bump. To aim this, a dual-band MWIR/LWIR detector based on an InAs/GaSb type-II superlattice nBn structure was designed and its performance was evaluated in this work. Since two absorber layers were separated by the barrier layer, each band can be detected by bias-selectable with one bump. The fabricated dual-band device exhibited the dark current and spectral response characteristics of MWIR and LWIR bands under negative and positive bias, respectively. Spectral crosstalk that is a major issue in dualband detectors was also improved. Finally, a 20 µm pitch 640 x 512 dual-band detector was fabricated, and both MWIR and LWIR images exhibited an average noise equivalent temperature difference of 30 mK or less at 80 K.
Źródło:
Opto-Electronics Review; 2023, 31, Special Issue; art. no. e144560
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-8 z 8

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