Fiber Positioner Based on Flexible Hinges Amplification Mechanism

Xue Cheng,Jian-Li Wang,Chang-Hua Liu,Liang Wang,Xu-dong Lin 한국물리학회 2019 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.75 No.1

Due to the nonlinear effect and the thermal effect, a single optical fiber has limitations in the output power. A beam combination of laser arrays based on adaptive optics can both improve the output power and ensure higher beam quality. This article puts forward one novel fiber positioner structure based on the flexible hinges amplification mechanism, which is the adaptive fiber optics collimator (AFOC), to correct tip-tilt aberration. The theoretical model was established, and the amplification ratios between the output displacement and device's structure parameters were calculated. The first 6 orders of the mode shape of the vibration of amplification mechanism was obtained by using a modal analysis. Analysis results revealed an excellent performance for the flexible hinges amplification mechanism. The novel fiber positioner has good prospects for applications in laser beam combination systems for ideal tip-tilt control.

《楚辭疏》訓詁硏究

張學城(Zhang Xuecheng),薄迎迎(Bo Yingying) 중국어문학연구회 2017 중국어문학논집 Vol.0 No.106

The “Chuci Shu” of Lu Shiyong is quite famous in the late Ming Dynasty for its study on the Chuci. When annotated, Lu Shiyong strived to concise, so that the book can be “easy to beginner”. Many features in this book can make people refresh. The article introduces the exegetical characteristics of Lu Shi Yong. Exegetical features include three aspects: pay attention to the old note, widely absorb views of other people; courage to innovate; attach importance to culture. These characteristics run through the exegetical study of "Chuci Shu", which clearly reflects Lu Shiyong’s attitude.The article also introduces the shortcomings of the exegetical study of "Chuci Shu", The inadequacies include three aspects: phonetic multi-leaf sound; many discourse from the sentence, less words; inaccurate citation.

Behaviour of Endplate Joints Subjected to Elevated Temperature after Cyclic Loads

Zhen Guo,Xuecheng Zhang,Xingzhi Jia 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.11

This paper presents the performance of an end-plate joint at elevated temperature after cyclic loads. Prime interest of the end-plate joints, subjected to elevated temperature, lies on the effect of three kinds of external conditions: monotonic loads, cyclic loads and local damages. Parametric studies have been systematically conducted using simplified models. The Behaviour of endplate joints subjected to high temperature is examined under two levels of damage caused to the structure, i.e., deformation damage and fracture damage under earthquake. Numerical results indicate that dead loads on beam and material properties of endplate joints are still playing a significant role in fire resistance. Under only deformation damage, the dominance of joints’ resistance to fire is still primarily the property of the material itself. Once experiencing fracture damage, for instance endplates fracture and bolts breakage, the behaviour of joints will degrade severely in post-earthquake fire. The results of this study demonstrate that the deformation damages has limited effect on the endplate joint at elevated temperature after an earthquake. The achieved results can be adopted during the design stage in order to minimize the probability of collapse in the fire.

Nanosized Carbon Black Combined with Ni₂O₃ as “Universal” Catalysts for Synergistically Catalyzing Carbonization of Polyolefin Wastes to Synthesize Carbon Nanotubes and Application for Supercapacitors

Wen, Xin,Chen, Xuecheng,Tian, Nana,Gong, Jiang,Liu, Jie,Rü,mmeli, Mark H.,Chu, Paul K.,Mijiwska, Ewa,Tang, Tao American Chemical Society 2014 Environmental science & technology Vol.48 No.7

<P>The catalytic carbonization of polyolefin materials to synthesize carbon nanotubes (CNTs) is a promising strategy for the processing and recycling of plastic wastes, but this approach is generally limited due to the selectivity of catalysts and the difficulties in separating the polyolefin mixture. In this study, the influence of nanosized carbon black (CB) and Ni<SUB>2</SUB>O<SUB>3</SUB> as a novel combined catalyst system on catalyzing carbonization of polypropylene (PP), polyethylene (PE), polystyrene (PS) and their blends was investigated. We showed that this combination was efficient to promote the carbonization of these polymers to produce CNTs with high yields and of good quality. Catalytic pyrolysis and model carbonization experiments indicated that the carbonization mechanism was attributed to the synergistic effect of the combined catalysts rendered by CB and Ni<SUB>2</SUB>O<SUB>3</SUB>: CB catalyzed the degradation of PP, PE, and PS to selectively produce more aromatic compounds, which were subsequently dehydrogenated and reassembled into CNTs via the catalytic action of CB together with Ni particles. Moreover, the performance of the synthesized CNTs as the electrode of supercapacitor was investigated. The supercapacitor displayed a high specific capacitance as compared to supercapacitors using commercial CNTs and CB. This difference was attributed to the relatively larger specific surface areas of our synthetic CNTs and their more oxygen-containing groups.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/esthag/2014/esthag.2014.48.issue-7/es404646e/production/images/medium/es-2013-04646e_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/es404646e'>ACS Electronic Supporting Info</A></P>

Fire Resistances of Restrained Steel Beams Subjected to Fire Loads

Zhen Guo,Rui Gao,Xuecheng Zhang,Xingzhi Jia 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.8

Conventional fire loads and fire resistances of a steel beam still lack an adequate correlation. This paper has established therelationship between the responses of restrained steel beams and fire actions by using a new definition of fire resistances and a newexpression of fire loads. By using reduction factors of elastic modulus and yield strengths, has presented three critical equations topredict the limit state of a restrained steel beam in a fire. Based on these equations and the heat transfer formula, the paper provided anew definition of fire resistances. By using the heat release rate and effective rate coefficient of thermal absorption, a new expressionof fire loads has been argued. Compared with tests, the proposed approach in this paper is in good agreement with the measuredvalues in tests. The results show that the new fire resistances could be able to reflect the facts of heat transfers and duration time. Incontrast to conventional fire loads, the new fire loads are more efficient to indicate a fire load.

Lead ion detection using glutathione-functionalized aluminum gallium nitride/gallium nitride high-electron-mobility transistors

Dong Xiaohu,Jiang Xuecheng,Gu Yan,Wei Chunlei,Xie Zhijian,Zhang Qi,Qian Weiying,Zhang Xiangyang,Zhu Chun,Lu Naiyan,Chen Guoqing,Yang Guofeng 한국물리학회 2023 Current Applied Physics Vol.50 No.-

This work presents a new approach for lead ion detection (Pb2+) using an aluminum gallium nitride/gallium nitride (AlGaN/GaN) high-electron-mobility transistor (HEMT) sensor. The AlGaN/GaN HEMT structure of the sensor was realized by functionalizing the gate area with glutathione (GSH). The crystalline and surface qualities of the AlGaN film were measured through X-ray diffraction and atomic force microscopy. The response of the sensor was measured in terms of the source–drain current with varying concentrations of Pb2+ ions at a fixed drain-to-source voltage. The sensitivity of the sensor was 29.3 μA/(mg/L), and it exhibited high selectivity toward Pb2+. The results show that using the GSH-functionalized AlGaN/GaN HEMT sensor is a promising strategy for Pb2+ ion detection.

Adaptive control for small-hole EDM process with wavelet transform detecting method

Yi Jiang,Wansheng Zhao,Xuecheng Xi,Lin Gu 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.6

To achieve an efficient small-hole EDM process, an accurate pulse monitoring strategy and a precise control are both required. In order to improve the efficiency and stability of the small-hole drilling process, an adaptive control system with a self-tuning regulator is developed. A high-speed EDM pulses monitoring system based on wavelet transform is implemented to measure the gap status, whose output is adopted as the feedback signals of the adaptive control system. The discharge waveforms are recorded and analyzed. The experimental results demonstrate that the arc pulse ratio during small-hole drilling process is reduced remarkably. The machining efficiency as well as the machining quality is improved significantly.

Energy and charge transfer effects for hybrids of perovskite CsPbBr₃ quantum dots on organic semiconducting rubrene nanosheet

Youn, Jongwon,Park, Cheol-Joon,Teng, Xuecheng,Lee, Kwang-Sup,Kim, Jeongyong,Joo, Jinsoo Elsevier 2019 Organic electronics Vol.65 No.-

<P><B>Abstract</B></P> <P>Functionalized perovskite CsPbBr<SUB>3</SUB> quantum dots (CsPbBr<SUB>3</SUB>-QDs) were loaded on the surface of a <I>p</I>-type organic rubrene (5,6,11,12-tetraphenyltetracene) nanosheet (NS) for the fabrication of a new hybrid nano-system. Using a high–resolution laser confocal microscope, the nanoscale photoluminescence (PL) characteristics of the CsPbBr<SUB>3</SUB>-QDs/rubrene-NS hybrids were investigated. We observed a significant enhancement of the PL intensity of the rubrene-NS after the hybridization with the CsPbBr<SUB>3</SUB>-QDs, which originated from the fluorescence resonance energy transfer from the CsPbBr<SUB>3</SUB>-QDs to the rubrene-NS. The PL enhancement ratio varied according to the density of the QDs on the NS. To investigate the hybridization effect with CsPbBr<SUB>3</SUB>-QDs on the electrical characteristics of the rubrene-NS, we fabricated field-effect transistors (FETs) using the pristine and hybrid samples as an active layer. The currents of both FETs using the pristine rubrene-NS and hybrid QDs/rubrene-NS increased with light irradiation through the contribution of photo-excited charges. After the hybridization with the CsPbBr<SUB>3</SUB>-QDs on the rubrene channel, both the electrical current and mobility decreased compared with the pristine rubrene-based FET. This can be explained by the relative decrease of hole concentration in the active channel region near dielectric layer through the interfacial charge transfer between the QDs and the NS, as well as the de-doping effect of the QDs on the rubrene-NS. Thus, we observed the energy and charge transfer effects for the CsPbBr<SUB>3</SUB>-QDs/rubrene-NS hybrids, which can be applied to advanced nanoscale photonics and optoelectronics.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Study of PL and charge transport characteristics of rubrene NS and perovskite CsPbBr<SUB>3</SUB>-QDs hybrid. </LI> <LI> Increase of PL intensity of rubrene NS by hybridization with CsPbBr<SUB>3</SUB>-QDs because of energy transfer effect. </LI> <LI> Electrical current and photoresponsivity of rubrene NS decreased due to de-doping effect by the QDs. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>The nanoscale photoluminescence and electrical characteristics of organic semiconducting rubrene nanosheet (NS) can be modulated via hybridization with perovskite CsPbBr<SUB>3</SUB>-QDs.</P> <P>[DISPLAY OMISSION]</P>

PspAG97A: A Halophilic α-Glucoside Hydrolase with Wide Substrate Specificity from Glycoside Hydrolase Family 97^s

( Wei Li ),( Han Fan ),( Chao He ),( Xuecheng Zhang ),( Xiaotang Wang ),( Jing Yuan ),( Zemin Fang ),( Wei Fang ),( Yazhong Xiao ) 한국미생물 · 생명공학회 2016 Journal of microbiology and biotechnology Vol.26 No.11

A novel α-glucoside hydrolase (named PspAG97A) from glycoside hydrolase family 97 (GH97) was cloned from the deep-sea bacterium Pseudoalteromonas sp. K8, which was screened from the sediment of Kongsfjorden. Sequence analysis showed that PspAG97A belonged to GH97, and shared 41% sequence identity with the characterized α-glucosidase BtGH97a. PspAG97A possessed three key catalytically related glutamate residues. Mutation of the glutamate residues indicated that PspAG97A belonged to the inverting subfamily of GH97. PspAG97A showed significant reversibility against changes in salt concentration. It exhibited halophilic ability and improved thermostability in NaCl solution, with maximal activity at 1.0 M NaCl/KCl, and retained more than 80% activity at NaCl concentrations ranging from 0.8 to 2.0 M for over 50 h. Furthermore, PspAG97A hydrolyzed not only α-1,4-glucosidic linkage, but also α-1,6- and α-1,2-glucosidic linkages. Interestingly, PspAG97A possessed high catalytic efficiency for long-chain substrates with α-1,6-linkage. These characteristics are clearly different from other known α-glucoside hydrolases in GH97, implying that PspAG97A is a unique α-glucoside hydrolase of GH97.

A comparative experimental study on the cross-plane thermal conductivities of nano-constructed Sb2Te3/(Cu, Ag, Au, Pt) thermoelectric multilayer thin films

Yang Gang,Pan Jiahui,Fu Xuecheng,Hu Zhiyu,Wang Ying,Wu Zhimao,Mu Erzhen,Yan Xue-Jun,Lu Ming-Hui 나노기술연구협의회 2018 Nano Convergence Vol.5 No.22

Thermoelectric multilayer thin films used in nanoscale energy conversion have been receiving increasing attention in both academic research and industrial applications. Thermal transport across multilayer interface plays a key role in improving thermoelectric conversion efficiency. In this study, the cross-plane thermal conductivities of nano-constructed Sb2Te3/(Cu, Ag, Au, Pt) thermoelectric multilayer thin films have been measured using time-domain thermoreflectance method. The interface morphology features of multilayer thin film samples were characterized by using scanning and transmission electron microscopes. The effects of interface microstructure on the cross-plane thermal conductivities of the multilayer thin films have been extensively examined and the thermal transfer mechanism has been explored. The results indicated that electron–phonon coupling occurred at the semiconductor/metal interface that strongly affected the cross-plane thermal conductivity. By appropriately optimizing the period thickness of the metal layer, the cross-plane thermal conductivity can be effectively reduced, thereby improving the thermoelectric conversion efficiency. This work presents both experimental and theoretical understanding of the thermal transport properties of Sb2Te3/metal multilayer thin film junctions with important implications for exploring a novel approach to improving the thermoelectric conversion efficiency. Introduction Thermoelectric multilayer thin films used in nanoscale energy conversion have been receiving increasing attention in both academic research and industrial applications. Thermal transport across multilayer interface plays a key role in improving thermoelectric conversion efficiency. In this study, the cross-plane thermal conductivities of nano-constructed Sb2Te3/(Cu, Ag, Au, Pt) thermoelectric multilayer thin films have been measured using time-domain thermoreflectance method. The interface morphology features of multilayer thin film samples were characterized by using scanning and transmission electron microscopes. The effects of interface microstructure on the cross-plane thermal conductivities of the multilayer thin films have been extensively examined and the thermal transfer mechanism has been explored. The results indicated that electron–phonon coupling occurred at the semiconductor/metal interface that strongly affected the cross-plane thermal conductivity. By appropriately optimizing the period thickness of the metal layer, the cross-plane thermal conductivity can be effectively reduced, thereby improving the thermoelectric conversion efficiency. This work presents both experimental and theoretical understanding of the thermal transport properties of Sb2Te3/metal multilayer thin film junctions with important implications for exploring a novel approach to improving the thermoelectric conversion efficiency. Introduction