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A research on the characteristics of an interleaver with a symmetrical resonator

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Optoelectronics Letters 2013年第1期9卷 21-24页

作者：鲁怀伟魏赟邬开俊王春丽蒋占军罗冠炜 school of Mathematics and Physics Lanzhou Jiaotong University school of Electronic and Information engineering Lanzhou Jiaotong University

In order to improve the transmission performance of the conventional Mach-Zehnder interferometer (MZI), a novel interleaver combining an "8"form ring resonator with a planar 3×3 single fiber coupler is proposed. Based on the phase modulation provided by the ring resonator, a flat filtering response is obtained by optimizing the coupling angle of resonator. The output expression is derived and numerical simulation is performed. The simulation indicates that the 0.5 dB passband and 25 dB stopband of the proposed interleaver are simultaneously improved remarkably, which are much wider than those of the single-stage MZI and the two-stage MZI interleavers, and the filtering performance of the proposed interleaver, which achieves a nearly square spectrum response, is also much better. Compared with the interleaver based on an asymmetrical MZI with a resonator in one arm, there is no difference between the intensities of two coherent beams in the condition of considering the influence of the propagation loss. Theoretical analysis shows that the influence of the propagation loss on extinction ratio can be effectively reduced.

关键词：环形谐振器非对称 Mach-Zehnder干涉仪光纤耦合器数值模拟传播损耗交织器传输性能

Relationship between the Intensity of Secondary Flow and Convection Heat Transfer in a Helically Coiled Circular Tube with Uniform Wall Temperature

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Journal of Thermal Science 2023年第3期32卷 1007-1022页

作者： ZHANG Jinlong ZHAO Chuangyao WANG Liangbi school of Mechanical engineering Lanzhou Jiaotong UniversityLanzhouGansu 730070China Key Laboratory of Railway Vehicle Thermal engineering of MOE Lanzhou Jiaotong UniversityLanzhou 730070China school of Building Services Science and engineering Xi'an University of Architecture and TechnologyXi'an 710055China

Numerical method is used to investigate fully developed laminar flow in helically coiled circular tube in this *** non-dimensional parameter(secondary flow Reynolds number Se)based on absolute vorticity flux along the mainstream is used to indicate the intensity of secondary flow caused by the centrifugal effect in helically coiled circular *** relationship between the intensity of secondary flow and the intensity of laminar convective heat transfer is *** effects of curvature and torsion on the enhancement of heat transfer are also *** results reveal that the absolute vorticity flux along the mainstream can be used to indicate the local or averaged intensity of secondary flow;the non-dimensional parameter of the absolute vortex along the main flow determines the convective heat transfer and friction *** relationships of Nusselt number and friction factor with the Se are *** effect of curvature on Nusselt number is obvious,but the effect of torsion on Nusselt number is less obvious.

关键词： helically coiled circular tube convective heat transfer heat transfer enhancement secondary flow

Regioselective Oxidation Approaches to Concise Synthesis of （±）-Canabisin D

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Chinese Journal of Chemistry 2015年第7期33卷 717-722页

作者： Wenling Li Qian Liu Hao Liu PeUan Chen Xi Yang Yingying Liu school of Chemical and Biological engineering Lanzhou Jiaotong University Lanzhou Gansu 730070 China

The regioselective effects of tert-butyl or bromine as the position-protecting group of feruloytyamide on the oxidative coupling reactions for the synthesis of natural （±）-canabisin D were investigated in detail. The coupling yield of 8-8-coupled aryldihydronaphthalene product of 5-Br-feruloytyamide was higher than that of tert-butyl substituted precursor under FeCl3·6H2O-acetone-water oxidative condition.

关键词： oxidative coupling biomimetic synthesis regioselectivity liganamides canabisin D

Fibers reinforced composite hydrogels with improved lubrication and load-bearing capacity

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Friction 2022年第1期10卷 54-67页

作者： Jiawei LI Luyao GAO Rongnian XU Shuanhong MA Zhengfeng MA Yanhua LIU Yang WU Libang FENG Meirong CAI Feng ZHOU lanzhou Institute of Chemical Physics.Chinese Academy of Sciences Lanzhou 730000China school of Mechanical engineering Lanzhou Jiaotong UniversityLanzhou 730050China school of Chemistry and Chemical engineering Lanzhou UniversityLanzhou 730000China

Hydrogels as one kind of soft materials with a typical three-dimensional(3D)hydrophilic network have been getting great attention in the field of ***,traditional hydrogels commonly show poor tribology performance under high-load conditions because of their poor mechanical strength and ***,pure chemical-crosslinking hydrogels mixed with different types of the micron-scale fibers can meet the requirements of strength and toughness for biolubrication materials,meanwhile the corresponding tribology performance improves *** a typical case,three kinds of reinforcement matrix including needle-punched fibers,alginate fibers,and cottons are separately combined with Poly(n-vinyl pyrrolidone)-poly 2-hydroxyethyl methacrylate(PVP-PHEMA)hydrogels to prepare fibers reinforced composite *** experimental results show that the mechanical properties of fibers reinforced composite hydrogels improve greatly comparable with pure PVP-PHEMA *** three kinds of fibers reinforced composite hydrogel,the as-prepared composite hydrogels reinforced with needle-punched fibers possess the best strength,modulus,and anti-tearing *** tests indicate that the fibers reinforced composite hydrogels demonstrate stable water-lubrication performance comparable with pure PVP-PHEMA ***,the hydrogel-spunlace fiber samples show the best load-bearing and anti-wear *** improved tribology performance of the composite hydrogels is highly related to mechanical property and the interaction between the fibers and hydrogel ***,spunlace fibers reinforced hydrogel materials with high load-bearing and low friction properties are expected to be used as novel biomimetic lubrication materials.

关键词： composite fibers load

Dynamic Risk-Warning of Center Diaphragm and Bench Composite Method During Construction

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Structural Durability & Health Monitoring 2022年第3期16卷 235-254页

作者： Xiaozhong Li Caiyun Sun school of Civil engineering Lanzhou Jiaotong UniversityLanzhou730070China

During the construction of subway tunnels,safety issues should not be ignored,so it is necessary to prevent and resolve the risk in time and ***,there are some shortcomings in the research of risk assessment,such as the subjectivity of initial data or the lack of scientific evaluation model,in order to solve the problem,this paper relies on the Changping section of the Guanhui Intercity Metro,in order to establish a dynamic risk-warn-ing model for the construction process of subway tunnel with the CD-Bench composite ***,a monitor-ing plan was equationted according to the specification requirements and the actual situation of the project,and based on this,an evaluation index system was established from five aspects:geological and support conditions,crown settlement,clearance convergence,and ground settlement and building ***,according to the established risk evaluation standards,the risk level of the index is determined by introducing extension theory and determining the combined weight of the index based on the distance ***,feedback the corresponding risk-warning signals and take control *** the application analysis shows that the model can alarm the risks during the tunnel construction process directly and timely,so the model is feasible and practical,and it is worthy of popularization and application in similar projects.

关键词： Risk-warning monitoring extension theory combination empowerment metro tunnel

Improvements on voltage-resistant performance of bipolar static induction transistor (BSIT) with buried gate structure

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Science China(Information Sciences) 2012年第4期55卷 962-970页

作者： WANG YongShun,FENG JingJing,LIU ChunJuan,WANG ZiTing,WANG ZaiXing & ZHANG CaiZhen school of Electronic and Information engineering,lanzhou jiaotong university,lanzhou 730070,China school of Electronic and Information engineering Lanzhou Jiaotong University Lanzhou China

The breakdown mechanism of power bipolar static induction transistor (BSIT) with buried gate structure is analyzed in depth.A power BSIT sample with high voltage-resistant capability has been designed and fabricated in this *** technological methods for improving high voltage performances are *** active region of BSIT is surrounded with a deep trench to avoid any probable influences of various defects on device *** field-limiting ring-shape junctions and one channel termination ring-shape junction are arranged around the gate region to reduce the electric field *** gate-source breakdown voltage BV GS of power BSIT has been increased to 110 V from previous value of 50-60 V,and its blocking voltage is increased to 1700 *** optimal geometrical dimensions for achieving the maximum breakdown voltage BV GS and blocking voltage V block are also represented in the paper.

关键词： bipolar static induction transistor voltage-resistant capability punch-through deep trench

Nickel ohmic contacts of high-concentration P-implanted 4H-SiC

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Journal of Semiconductors 2012年第3期33卷 118-121页

作者：刘春娟刘肃冯晶晶吴蓉 school of Physical Science and Technology Lanzhou University school of Electronic and Information engineering Lanzhou Jiaotong University

Different-dose phosphorus ion implantation into 4H-SiC followed by high-temperature annealing was ***/BN and graphite post-implantation annealing for ion-implanted SiC at 1650℃for 30 min was conducted to electrically activate the implanted P~＋ *** contacts to the P~＋-implanted 4H-SiC layers were examined by transmission line model and Hall measurements fabricated on P-implanted（0001）.The results indicated that a high-quality ohmic contact and specific contact resistivity of 1.30×10^（-6）Ω·cm^2 was obtained for the P~＋-implanted 4H-SiC ***ρC values of the Ni-based implanted layers decreased with increasing P doping concentrations,and a weaker temperature dependence was observed for different samples in the 200-500K temperature range.

关键词： ohmic contacts phosphorus ion implantation contact resistance Hall concentration silicon carbide

Metabolites change of Scenedesmus obliquus exerted by AgNPs

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Journal of Environmental Sciences 2019年第2期31卷 310-318页

作者： Pu Wang Bo Zhang Hui Zhang Yiliang He Choon Nam Ong Jun Yang school of Environmental Science & engineering Shanghai Jiaotong University school of Municipal and Environmental engineering Lanzhou Jiaotong University NUS Environmental Research Institute National University of Singapore

With increasing emission of silver nanoparticles(AgNPs) into the environment, it is important to understand the effects of ambient concentration of AgNPs. The biological effects of AgNPs on Scenedesmus obliquus, a ubiquitous freshwater microalgae, was evaluated. AgNPs exerted a minor inhibitory effect at low doses. Non-targeted metabolomic studies were conducted to understand and analyze the effect of AgNPs on algal cells from a molecular perspective. During the 48 hr of exposure to AgNPs, 30 metabolites were identified, of which nine had significant changes compared to the control group. These include D-galactose, sucrose, and *** carbohydrates are involved in the synthesis and repair of cell walls. Glycine, an important constituent amino acid of glutathione, increased with AgNP exposure concentration increasing, likely to counteract an increased intracellular oxidative stress. These results provide a new understanding of the toxicity effects and mechanism of AgNPs. These metabolites could be useful biomarkers for future research, employed in the early detection of environmental risk from AgNPs.

关键词： Silver nanoparticles (AgNPs) Scenedesmus obliquus Metabolomics Molecular mechanism

Self-supported amorphous nanoporous nickel-cobalt phosphide catalyst for hydrogen evolution reaction

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Progress in Natural Science:Materials International 2021年第2期31卷 201-206页

作者： Yao Pang Shengli Zhu Zhenduo Cui Yanqin Liang Zhaoyang Li Shuilin Wu school of Materials Science and engineering Tianjin University school of Materials Science and engineering Lanzhou Jiaotong University

Hydrogen evolution reaction(HER) through electrocatalysis using cost-efficient and long-term stable bimetallic phosphide as electrocatalyst holds a great promise for sustainable clean energy technologies. In this study, self-supported nanoporous Ni-Co-P(np-Ni-Co-P) catalyst with amorphous structure was synthesized by utilizing a facile electrochemical dealloying strategy. The results showed that due to the nanoporous structure, disorder atomic arrangement and alloying effect, the np-Ni-Co-P exhibited outstanding electrocatalytic performance for HER with low overpotential of 114 m V at a current density of 10 mA cm~2, small Tafel slope(57.3 mV dec-1) and good long-term durability in 1 M KOH. The synergetic effect of Ni and Co elements improves the intrinsic activity of the active sites. This research provides a direction for the exploration of bimetallic phosphides toward HER in the water splitting process.

关键词： Hydrogen evolution reaction Metal phosphide Electrocatalyst Dealloying Amorphous alloys