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Theoretical optimization of complete forbidden bands in woodpile-type photonic crystals

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Optoelectronics Letters 2008年第5期4卷 358-360页

作者： zhan yi ZHENG yi LI Xiu-Xia College of Graphic Arts Qufu Normal University Rizhao 276826 China College of Science Beijing Jiaotong University Beijing 100044 China

Based on the plane-wave method, the optical properties of complete forbidden bands of woodpile structure photonic crystal with an entire Lattice rotation of 45° in the x-y plane were theoretically studied in terms of height-to-pitch ratios, filling factors, and rotation angles. The calculated results show that the gap to mid-gap ratio changes slightly with a filling fraction ranging from 0.25 to 0.30. The optimum height-to-pitch ratio is about 1.3. The gap to mid-gap ratio reaches more than 0.18 when the rotation angle increases from 40° to 50° and the maximum gap to mid-gap ratio of 0.2 remains unchanged for the rotation angle from 42°to 48° with a constant height-to-pitch ratio of 1.3. The gap to mid-gap ratio reaches the maximum value of 0.2 when the height-to-pitch ratio is 1.3. This woodpile-type photonic crystal can provide large band gaps within a wider parameter range, which makes it convenient to manufacture three-dimensional photonic crystals in the laboratory.

关键词：晶体平面波方法禁用波段木料堆结构

Electrodeposited Sulfur and CoxS Electrocatalyst on Buckypaper as High-Performance Cathode for Li-S Batteries

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Nano-Micro Letters 2020年第10期12卷 263-275页

作者： yi zhan Andrea Buffa Linghui Yu Zhichuan JXu Daniel Mandler School of Materials Science and Engineering Nanyang Technological UniversitySingapore 639798Singapore Institute of Chemistry The Hebrew University of Jerusalem9190401 JerusalemIsrael Campus for Research Excellence and Technological Enterprise(CREATE) Singapore-HUJ Alliance for Research and Enterprise(SHARE)Singapore 138602Singapore

Lithium-sulfur batteries(LSBs)are considered as the next generation of advanced rechargeable batteries because of their high energy *** this study,sulfur and CoxS electrocatalyst are deposited on carbon nanotube buckypaper(S/CoxS/BP)by a facile electrodeposition method and are used as a binder-free high-performance cathode for *** sulfur is deposited on buckypaper by electrooxidation of a polysulfide solution(-S6^2-).This approach substantially increased the current and time efficiency of sulfur electrochemical deposition on conductive material for LSBs.S/CoxS/BP cathode could deliver an initial discharge capacity as high as 1650 mAh g^-1 at 0.1 C,which is close to the theoretical capacity of *** current rate of 0.5 C,the S/CoxS/BP has a capacity of 1420 mAh g^-1 at the first cycle and 715 mAh g^-1 after 500 cycles with a fading rate of 0.099%per *** high capacity of S/CoxS/BP is attributed to both the homogeneous dispersion of nanosized sulfur within BP and the presence of CoxS *** sodium dodecyl sulfate(SDS)pretreatment of BP renders it polarity to bind polysulfides and thus facilitates the good dispersibility of nanosized sulfur within *** catalyst accelerates the kinetics of polysulfide conversion and reduces the presence of polysulfide in the cathode,which suppresses the polysulfide diffusion to anode,i.e.,the shuttle *** mitigation of the active material loss improves not only the capacity but also the cyclability of S/CoxS/BP.

关键词： Electrodeposition Lithium sulfur batteries Buckypaper Electrocatalysts

Interface materials for perovskite solar cells

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Rare Metals 2021年第11期40卷 2993-3018页

作者： yi-Heng zhang Yuan Li School of Materials Science and Engineering South China University of TechnologyGuangzhou 510641China

Perovskite solar cells exhibit great potential to become commercial photovoltaic technology due to their high power conversion efficiency,low cost,solution processability,and facile large-area device *** engineering plays a significant role to optimize device *** the anode in the inverted devices,this review introduces the progress on the modification of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)including chemical structure alteration,physical doping,and solution *** present the recent advances of dopant-free hole transport materials widely applied in mesoporous and conventional devices,outlining their innovation with novel molecular design concepts toward promising material properties,and device *** the cathode,various metal oxide and organic electron transport materials are covered and the different modification strategies and related mechanisms are *** importantly,simple synthesis process,inexpensive raw materials and highly reproducible photovoltaic performance are the main consideration for the design of all the interface ***,an outlook and some suggestions regarding the future interface engineering are proposed based on the summary of the current development status and working mechanism of interface materials.

关键词： Perovskite solar cells Interface Hole transport materials Electron transport materials PEDOT:PSS

Microstructural evolution and aging behavior of Mg-4.5Y-2.5Nd-1.0Gd-0.5Zr alloys with different Zn additions

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Rare Metals 2021年第8期40卷 2188-2196页

作者： Zheng Tian Qiang Yang Kai Guan zhan-yi Cao Jian Meng Key Laboratory of Automobile Materials of Ministry of Education Department of Materials Science and EngineeringJilin UniversityChangchun130025China State Key Laboratory of Rare Earth Resources Utilization Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun130022China

Microstructures and mechanical properties of Mg-4.5 Y-2.5 Nd-1.0 Gd-0.5 Zr-xZn(x=0,0.5,1.0,and 1.5;wt%)alloys under as-cast and peak-aged states were investigated in this *** results indicate that the intermetallic phase components are closely dependent on Zn *** as-cast state,the dominant eutectic phase is Mg5 RE in the alloys with 0 wt%and 0.5 wt%Zn additions while Mg5 RE,18 R-and 14 H-LPSO(long period stacking ordered)phases in the alloys with 1.0 wt%and1.5 wt%Zn *** solution and peak-aging,the highest strength and hardness were obtained on the alloy with 0.5 wt%Zn *** electron microscopy(TEM)characterizations revealed that there are denser and finer precipitates on basal(β’)and prismatic(γ’)planes,***,the excellent mechanical performance of the alloy with 0.5 wt%Zn addition is mainly due to precipitation strengthening and grain boundary strengthening.

关键词： Magnesium alloy Intermetallic phase Precipitates Mechanical property

Effects of magnesium and copper additions on tensile properties of Al-Si-Cr die casting alloy under as-cast and T5 conditions

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China Foundry 2023年第1期20卷 12-22页

作者： Hong-yi zhan yi-wu Xu Pan Wang Jian-feng Wang Jin-ping Li Le-peng zhang General Motors Global Research&Development China Science LaboratoryShanghai 201206China School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China General Motors(China)Investment Co. Ltd.Shanghai 201206China China International Intellectech Corporation(CIIC) Beijing 100004China

Aluminum high pressure die casting(HPDC)technology has evolved in the past decades,enabling stronger and larger one-piece casting with significant part *** also offers a higher design freedom for more mass-efficient thin-walled body *** body structures that require excellent ductility and fracture toughness to be joined with steel sheet via self-piercing riveting(for instance,shock towers and hinge pillars,etc.),a costly T7 heat treatment comprising a solution heat treatment at elevated temperatures(450℃-500℃)followed by an over-ageing heat treatment is needed to optimize microstructure for meeting product *** enable cost-efficient mass production of HPDC body structures,it is important to eliminate the expensive T7 heat treatment without sacrificing mechanical *** die cast alloy chemistry is a potential solution to improve fracture toughness and ductility of the HPDC *** present study intends to tailor the Mg and Cu additions for a new Al-Si-Cr type die casting alloy(registered as A379 with The Aluminum Association,USA)to achieve the desired tensile properties without using T7 heat *** was found that Cu addition should be avoided,as it is not effective in enhancing strength while degrades tensile *** addition is very effective in improving strength and has minor impact on tensile *** investigated Al-Si-Cr alloy with a nominal composition of Al-8.5wt.%Si-0.3wt.%Cr-0.2wt.%Fe shows comparable tensile properties with the T7 treated AlSi10MnMg alloy which is currently used for manufacturing shock towers and hinge pillars.

关键词： Al-Si alloy intermetallics high pressure die casting tensile property T7 heat treatment

Secondary Structure Analysis of Native Cellulose by Molecular Dynamics Simulations with Coarse-Grained Model

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Chinese Journal of Chemical Physics 2012年第2期25卷 191-198,I0004页

作者： Shuai Wu Hai-yi zhan Hong-ming Wang Yan Ju Institute for advanced study department of chemistryNanchang UniversityNanchang 330031China Nanchang Institute of Technology Nanchang UniversityNanchang 330031China

The secondary structure of different Iβ cellulose was analyzed by a molecular dynamics sim- ulation with MARTINI coarse-grained force field, where each chain of the cellulose includes 40 D-glucoses units. Calculation gives a satisfied description about the secondary structure of the cellulose. As the chain number increasing, the cellulose becomes the form of a helix, with the diameter of screw growing and spiral rising. Interestingly, the celluloses with chain number N of 4, 6, 24 and 36 do show right-hand twisting. On the contrast, the celluloses with N of 8, 12, 16 chains are left-hand twisting. These simulations indicate that the cellulose with chain number larger than 36 will break down to two parts. Besides, the result indicates that 36-chains cellulose model is the most stable among all models. Furthermore, the Lennard-Jones potential determines the secondary structure. In addition, an equation was set up to analyze the twisting structure.

关键词： Iβ cellulose Coarse-grained model Secondary structure Molecular dynamics

多维度校企合作实现复合型拔尖创新人才自主培养

维普期刊数据库评论

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科教文汇 2025年第1期 1-4页

作者：占艺彭一鸣周钰华中科技大学党委组织部华中科技大学生命科学与技术学院

党的二十大报告对“着力造就拔尖创新人才”提出要求。新工科建设强调要培养适应和引领新一轮科技革命和产业变革的卓越工程科技人才。围绕这个目标，华中科技大学生命科学与技术学院从多个维度强化校企合作培养，将产业变革中对拔尖创... 详细信息

党的二十大报告对“着力造就拔尖创新人才”提出要求。新工科建设强调要培养适应和引领新一轮科技革命和产业变革的卓越工程科技人才。围绕这个目标，华中科技大学生命科学与技术学院从多个维度强化校企合作培养，将产业变革中对拔尖创新人才培养的实际需要精准融入高校新工科复合型人才培养体系，坚持“四个面向”，探索和实践以解决复杂问题为牵引的拔尖创新人才自主培养新模式。

关键词：新工科校企合作拔尖创新人才

Microstructure and mechanical properties of Mg–Zn–(Nd)–Zr alloys with different extrusion processes

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Rare Metals 2016年第11期35卷 841-849页

作者： Xin Qiu Qiang Yang zhan-yi Cao Yong-Bing Liu Jian Meng Key Laboratory of Automobile Materials of Ministry of Education Department of Materials Science and EngineeringJilin University State Key Laboratory of Rare Earth Resources Utilization Changchun Institute of Applied ChemistryChinese Academy of Sciences

The effect of Nd addition and the influence of extrusion processes on the microstructure and mechanical properties of Mg-6Zn-0.5Zr（ZK60） and Mg-6Zn-1.5Nd-0.5Zr（ZKNd602） alloys were investigated. Nd element can obviously refine the microstructure of both as-cast and asextruded Mg-Zn-Nd-Zr alloy. All of the extruded alloys exhibit a bimodal grain structure composed of equiaxedfine recrystallized（DRXed） grains and elongated coarse un DRXed grains. It is necessary to achieve high strength,particularly the yield strength, for ZKNd602 alloy, when it is extruded with a lower extrusion temperature, a suitable extrusion ratio and a relatively lower extrusion ram speed. In this study, the ultimate tensile strength（UTS）,yield strength（YS） and elongation（El） of the extruded ZKNd602 alloy were 421 MPa, 402 MPa and 6.7 %,respectively, with extrusion temperature of 290 °C, extrusion ratio of 18：1 and a ram speed of approximate0.4 mm·s^（-1）. Meanwhile, the extrusion process has obvious effects on the room-temperature properties but weak effects on the high-temperature properties.

关键词： Magnesium alloy Rare earth element Extrusion process Microstructure Mechanical property

Agricultural irrigation requirements under future climate scenarios in China

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Journal of Arid Land 2015年第2期7卷 224-237页

作者： Xiu Fang ZHU An Zhou ZHAO yi zhan LI Xian Feng LIU State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal University College of Resources Science and Technology Beijing Normal University

Projecting future water demand, especially in terms of agricultural irrigation demand, as well as identifying high-risk areas and establishing appropriate water demand management has become increasingly important in China. Climate scenarios provide opportunities to predict future irrigation requirements （IRs）. We examined changes in IRs and agricultural drought in response to rising greenhouse gas concentrations in China using eight global climate models from the Intergovernmental Panel on Climate Change Fourth Assessment Report. In this research, Northeast China, the North China Plain and the Yarlung Tsangpo River Valley area in southeastern Tibet were estimated to receive more precipitation in the future, whereas Southeast and Northwest China, especially the Junggar and Tarim basins in Xinjiang Uygur autonomous region, will receive less precipitation. IRs will undergo a significant increase in summer （June-August）, especially in July, whereas the smallest increase was predicted to occur in autumn （September-November）. Middle rice was identified as the greatest contributor to the increase in total IRs. The areas predicted to experience significant increases in IRs include Northwest China （the Tarim and Junggar basins in Xinjiang Uygur autonomous region, the Hexi Corridor in Gansu province and the Guanzhong Plain in Shaanxi province）, Southeast China （especially Fujian province）, and Southwest China （Yarlung Tsangpo River Valley area in Tibet and the Sichuan Basin）.

关键词： agricultural drought water demand agricultural irrigation requirement climate change IPCC scenarios