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| 1 | The Yellow Sea green tides were dominated by one species, Ulva (Enteromorpha) prolifera, from 2007 to 2011显示文摘Green tides have occurred in the Yellow Sea successively from 2007 to 2011. Genetic analysis of the 5-year green-tide-forming algae needs to be performed to determine the source of the biomass and understand the mechanism of the green tide blooms. In this study, free-floating green algae were collected at different sites in the Yellow Sea in 2010 and 2011. Data on 182 free-floating samples and 155 attached Ulva samples from previous studies on the Yellow Sea green tides from 2007 to 2009 were also taken into consideration. Morphology observation and molecular phylogenetic analyses indicated that the Yellow Sea green tides were dominated by a single species, Ulva prolifera, from 2007 to 2011. Considering that at least five Ulva species inhabit the north coast of China, the unialgal composition of the green tides implied that (1) there may be some special physiology and propagation pathways of U. prolifera for its rapid expansion, (2) the mechanisms of the Yellow Sea green tide formation were similar for the last five years, and (3) the intra-species genetic variation and population structure of U. prolifera need to be studied to determine the exact origin of the bloom-forming biomass. | ZHAO Jin JIANG Peng LIU ZhengYi WEI Wei LIN HanZhi LI FuChao WANG JinFeng QIN Song | 2013 | Chinese Science Bulletin2013，58，19： | 27 |
| 2 | ANALYSIS OF MECHANICS IN BALL SPINNING OF THIN-WALLED TUBE显示文摘Ball spinning is applied to manufacturing thin-walled tube with high precision and high mechanical properties. On the basis of plastic mechanics,by simplifying ball spinning of thin-walled tube as plane strain problem,slab method is used for the purpose of calculating the contact deformation pressure. The spinning force components,the torsional moment,the deformation power and the deformation work are calculated further as well. The influence of the two important process parameters such as the feed ratio and the ball diameter on the spinning force components is analyzed in order to further control the spinning force components by regulating the two process variables during the ball spinning process. The stress and strain state in deformable zone as well as mechanics boundary conditions in ball spinning are obtained. The effect of the three spinning force components on the formability of the spun part is analyzed and validated through the ball spinning experiments. The theoretical and experimental results show that the radial spinning component plays a significant role in ball spinning of thin-walled tube,and the mechanics situation in backward ball spinning contributes to enhancing the plasticity of the metal material,but that in forward ball spinning contributes to advancing the axial flow of the metal material. | JIANG Shuyong REN Zhengyi | 2008 | Chinese Journal of Mechanical Engineering2008，21，1： | 18 |
| 3 | CRISPR/Cas9-mediated PINK1 deletion leads to neurodegeneration in rhesus monkeys显示文摘Dear Editor,PINK1 mutations cause autosomal recessive and early-onset Parkinson’s disease(PD)with selective neurodegeneration.Unfortunately,current PINK1 knockout(KO)mouse1,2 and pig models3,4 are unable to recapitulate the selective and overt neurodegeneration seen in PD patients.Furthermore,endogenous Pink1 in the mouse brain is expressed at very low levels and can only be detected via immunoprecipitation,5 meaning that PINK1’s function in the mammalian brain needs to be assessed using larger animals that are closer to humans.We previously used CRISPR/Cas9 to target the monkey gene in one-cell stage embryos.6 Using the same approach,we designed two gRNAs to target exon 2(T1)and exon 4(T2),which encode a kinase domain in the PINK1 gene of rhesus monkeys(Fig.1a).CRISPR/Cas9 and PINK1 gRNAs were injected into one-cell stage rhesus monkey embryos.A T7E1 assay and sequencing of PCR products from the injected embryos showed high efficiency(61.5%)in targeting PINK1(Fig.1b and Supplementary information,Fig.S1).Transfer of 87 embryos to 28 surrogate rhesus monkeys resulted in 11 pregnancies(39.2%)(Fig.1b).Eleven fetuses developed to term and were born naturally.Of these live monkeys,eight carried PINK1 mutations(M),and three were wild type(WT).However,three mutant monkeys(M1,M3 and M4)were newborn triplets that struggled to survive and died 3-4 days after birth.One WT newborn monkey also died after a difficult labor.Another mutant monkey(M2)died 7 days after birth without noticeable warning signs or symptoms.The other three mutant monkeys(M6,M7 and M8)have lived for three years;M5,however,reduced its food intake and showed weakness at the age of 1.5 years,and died 30 days after anesthesia for MRI examination. | Weili Yang Yunbo Liu Zhuchi Tu Chong Xiao Sen Yan Xishan Ma Xiangyu Guo Xiusheng Chen Peng Yin Zhengyi Yang Su Yang Tianzi Jiang Shihua Li Chuan Qin Xiao-Jiang Li | 2019 | Cell Research2019，29，4： | 12 |
| 4 | Hierarchically structured porous materials: synthesis strategies and applications in energy storage显示文摘To address the growing energy demands of sustainable development,it is crucial to develop new materials that can improve the efficiency of energy storage systems.Hierarchically structured porous materials have shown their great potential for energy storage applications owing to their large accessible space,high surface area,low density,excellent accommodation capability with volume and thermal variation,variable chemical compositions and well controlled and interconnected hierarchical porosity at different length scales.Porous hierarchy benefits electron and ion transport;and mass diffusion and exchange.The electrochemical behavior of hierarchically structured porous materials varies with different pore parameters.Understanding their relationship can lead to the defined and accurate design of highly efficient hierarchically structured porous materials to enhance further their energy storage performance.In this review,we take the characteristic parameters of the hierarchical pores as the survey object to summarize the recent progress on hierarchically structured porous materials for energy storage.This is the first of this kind exclusively to survey the performance of hierarchically structured porous materials from different porous characteristics.For those who are not familiar with hierarchically structured porous materials,a series of very significant synthesis strategies of hierarchically structured porous materials are firstly and briefly reviewed.This will be beneficial for those who want to quickly obtain useful reference information about the synthesis strategies of new hierarchically structured porous materials to improve their performance in energy storage.The effect of different organizational,structural and geometric parameters of porous hierarchy on their electrochemical behavior is then deeply discussed.We outline the existing problems and development challenges of hierarchically structured porous materials that need to be addressed in renewable energy applications.We hope that this review can stimulate strong intuition into the design and application of new hierarchically structured porous materials in energy storage and other fields. | Liang Wu Yu Li Zhengyi Fu Bao-Lian Su | 2020 | National Science Review2020，7，11： | 9 |
| 5 | Self-supported high-entropy alloy electrocatalyst for highly efficient H_(2) evolution in acid condition显示文摘Developing non-precious catalysts as Pt substitutes for electrochemical hydrogen evolution reaction(HER)with superior stability in acidic electrolyte is of critical importance for large-scale,low-cost hydrogen production from water.Herein,we report a CoCrFeNiAl high-entropy alloy(HEA)electrocatalyst with self-supported structure synthesized by mechanical alloying and spark plasma sintering(SPS)consolidation.The HEA after HF treatment and in situ electrochemical activation for 4000 cycles of cyclic voltammetry(HF-HEAa2)presents favourable activity with overpotential of 73 mV to reach a current density of 10 mA cm^(2) and a Tafel slope of 39.7 mV dec1.The alloy effect of Al/Cr with Co/Fe/Ni at atomic level,high-temperature crystallization,as well as consolidation by SPS endow CoCrFeNiAl HEA with high stability in 0.5 M H2SO4 solution.The superior performance of HF-HEAa2 is related with the presence of metal hydroxides/oxides groups on HEA. | Peiyan Ma Mingming Zhao Long Zhang Heng Wang Junfeng Gu Yuchen Sun Wei Ji Zhengyi Fu | 2020 | Journal of Materiomics2020，6，4： | 8 |
| 6 | A fundamental theorem for eco-environmental surface modelling and its applications显示文摘We propose a fundamental theorem for eco-environmental surface modelling(FTEEM) in order to apply it into the fields of ecology and environmental science more easily after the fundamental theorem for Earth’s surface system modeling(FTESM). The Beijing-Tianjin-Hebei(BTH) region is taken as a case area to conduct empirical studies of algorithms for spatial upscaling, spatial downscaling, spatial interpolation, data fusion and model-data assimilation, which are based on high accuracy surface modelling(HASM), corresponding with corollaries of FTEEM. The case studies demonstrate how eco-environmental surface modelling is substantially improved when both extrinsic and intrinsic information are used along with an appropriate method of HASM. Compared with classic algorithms, the HASM-based algorithm for spatial upscaling reduced the root-meansquare error of the BTH elevation surface by 9 m. The HASM-based algorithm for spatial downscaling reduced the relative error of future scenarios of annual mean temperature by 16%. The HASM-based algorithm for spatial interpolation reduced the relative error of change trend of annual mean precipitation by 0.2%. The HASM-based algorithm for data fusion reduced the relative error of change trend of annual mean temperature by 70%. The HASM-based algorithm for model-data assimilation reduced the relative error of carbon stocks by 40%. We propose five theoretical challenges and three application problems of HASM that need to be addressed to improve FTEEM. | Tianxiang YUE Na ZHAO Yu LIU Yifu WANG Bin ZHANG Zhengping DU Zemeng FAN Wenjiao SHI Chuanfa CHEN Mingwei ZHAO Dunjiang SONG Shihai WANG Yinjun SONG Changqing YAN Qiquan LI Xiaofang SUN Lili ZHANG Yongzhong TIAN Wei WANG Ying’an WANG Shengnan MA Hongsheng HUANG Yimin LU Qing WANG Chenliang WANG Yuzhu WANG Ming LU Wei ZHOU Yi LIU Xiaozhe YIN Zong WANG Zhengyi BAO Miaomiao ZHAO Yapeng ZHAO Yimeng JIAO Ufra NASEER Bin FAN Saibo LI Yang YANG John PWILSON | 2020 | Science China Earth Sciences2020，63，8： | 7 |
| 7 | Observations of several characteristics of aeolian sand movement in the Taklimakan Desert显示文摘With both sides of the Taklimakan Desert highway line as the study area, three typical aeolian sand landforms, i.e. complex dune ridge, barchan dune and flat sand land, were selected as sand beds for the observation, analysis and research of the characteristics of aeolian sand movement such as aeolian sand stream structure, sand transport intensity, etc. in the Taklimakan Desert. The results show that there is a linear relation between the height and the log of sand transport rate over transverse dune chain, longitudinal dune ridge and flat sand land, i.e. the sand transport percentage decreases exponentially with increasing height. Sand transport rate within the 10 cm height above the bed surface accounts for 80%-95% of the total sand transport rate of the observed height (40 cm), while the sand transport rate in 20 cm occupies 98% of the total amount. Sand transport rate (g·cm-1·min-1) differs greatly with respect to different landform types and different topographic positions. Based on the investigation and analysis on aeolian sand landform origin, morphological type and distribution feature, the two typical landform assemblages, complex transverse dune chain-alluvial plain and huge longitudinal dune ridge-interridge lowland in the Taklimakan Desert were divided into several characteristic zones of aeolian sand movement states. From this one can qualitatively judge the types and severities of sand disasters at various topographic positions in the engineering installation region and further put forward concrete schemes and measures to control sand damages. | HAN Zhiwen DONG Zhibao WANG Tao CHEN Guangting YAN Changzhen YAO Zhengyi | 2004 | Science China Earth Sciences2004，47，1： | 7 |
| 8 | Influence of Golmud-Lhasa Section of Qinghai-Tibet Railway on Blown Sand Transport显示文摘The Qinghai-Tibet Railway(QTR) passes through 281 km of sandy land, 11.07 km of which causes serious sand damage to the railway and thus, the control of blown sand is important for the safe operation of the railway. Construction of the railway and sand prevention system greatly changed the blown sand transport of the primary surface. Effective and feasible sand-control measures include stone checkerboard barriers(SCBs), sand fences(SFs), and gravel coverings. This study simulated the embankments, SCBs and SFs of the QTR in a wind tunnel, and analyzed their respective wind profile, sand deposition, and sand-blocking rate(SBR) in conjunction with field data, aiming at studying the influence of Golmud-Lhasa section of the QTR and sand prevention system on blown sand transport. The results of wind tunnel experiments showed that wind speed increased by 67.7%–77.3% at the upwind shoulder of the embankment and decreased by 50.0%–83.3% at upwind foot of embankment. Wind speed decreased by 50.0%–100.0% after passing through the first SF, and 72.2%–100.0% after the first row of stones within the first SCB grid. In the experiment of sand deposition, the higher the wind speed, the lower the SBR of SCB and SF. From field investigation, the amount of sand blocked by the four SFs decreased exponentially and its SBR was about 50.0%. By contrast, SCB could only block lower amounts of sand, but had a higher SBR(96.7%) than SF. Although, results show that SFs and SCBs along the Golmud-Lhasa section of the QTR provide an obvious sand blocking effect, they lead to the deposition of a large amount of sand, which forms artificial dunes and becomes a new source of sand damage. | XIAO Jianhua YAO Zhengyi QU Jianjun | 2015 | Chinese Geographical Science2015，25，1： | 6 |
| 9 | Analysis of genetic variation within and among Ulva pertusa (Ulvaceae,Chlorophyta) populations using ISSR markers显示文摘Ulva pertusa is a native species to Asia along the western coast of Pacific Ocean,with new occurrence records in the eastern coast of Pacific,the northwest coast of Atlantic and the Mediterranean Sea.However,little is known about its population genetic structure.In this study,twelve U.pertusa populations from 3 coastal areas of China:Qingdao,Yantai and Dalian,were applied to ISSR analysis.The selected 4 ISSR primers amplified 120 polymorphic bands totally.Nei's gene diversity (H) ranged from 0.0729 to 0.1496,and Shannon's information index (I) ranged from 0.1072 to 0.2196.Genetic diversity was greater within Qingdao populations (H=0.2069,I=0.3232).Analysis of molecular variance (AMOVA) showed the greatest variance within populations (68.57%),much less variance among populations (22.63%) and among areas (8.79%).Unweighted pair-group mean analysis (UPGMA) indicated that clustering of U.pertusa individuals mainly relates to their populations and geographic distances separating those populations.Genetic differentiation and limited gene flow among U.pertusa populations were indicated by ISSR analysis. | ZHAO Jin JIANG Peng LI Nan WANG JinFeng LIU ZhengYi QIN Song | 2010 | Chinese Science Bulletin2010，55，8： | 6 |
| 10 | Characteristics of daily extreme wind gusts on the Qinghai-Tibet Plateau, China显示文摘Severe wind is a major natural hazard and a main driver of desertification on the Qinghai-Tibet Plateau. Generally, studies of Qinghai-Tibet Plateau's wind climatology focus on mean wind speeds and its gust speeds have been seldom investigated. Here, we used observed daily maximum gust speeds from a 95-station network over a 5-year period(2008–2012) to analyze the characteristics of extreme wind speeds and directions by fitting Weibull and Gumbel distributions. The results indicated the spatial distribution of extreme wind speeds and their direction on the Qinghai-Tibet Plateau is highly variable, with its western portion prone to greater mean speeds of extreme wind gusts than its eastern portion. Maximum extreme wind speeds of 30.9, 33.0, and 32.2 m/s were recorded at three stations along the Qinghai Tibet Railway. Severe winds occurred mostly from November to April, caused primarily by the westerly jet stream. Terrain greatly enhances the wind speeds. Our spatial analysis of wind speed data showed that the wind speeds increased exponentially with an increasing altitude. We also assessed the local wind hazard by calculating the return periods of maximum wind gusts from the observational data based on the statistical extreme value distributions of these wind speeds. Further attention should be given to those stations where the yearly maximum daily extreme wind speed increased at a rate greater than that of mean value of daily extreme wind speeds. Severe extreme wind events in these regions of the plateau are likely to become more frequent. Consequently, building structural designers working in these areas should use updated extreme wind data rather than relying on past data alone. | YAO Zhengyi LI Xiaoying XIAO Jianhua | 2018 | Journal of Arid Land2018，10，5： | 6 |
| 11 | An App knock-in rat model for Alzheimer’s disease exhibiting Aβand tau pathologies,neuronal death and cognitive impairments显示文摘A major obstacle in Alzheimer’s disease(AD)research is the lack of predictive and translatable animal models that reflect disease progression and drug efficacy.Transgenic mice overexpressing amyloid precursor protein(App)gene manifest non-physiological and ectopic expression of APP and its fragments in the brain,which is not observed in AD patients.The App knock-in mice circumvented some of these problems,but they do not exhibit tau pathology and neuronal death.We have generated a rat model,with three familiar App mutations and humanized Aβsequence knocked into the rat App gene.Without altering the levels of full-length APP and other APP fragments,this model exhibits pathologies and disease progression resembling those in human patients:deposit of Aβplaques in relevant brain regions,microglia activation and gliosis,progressive synaptic degeneration and AD-relevant cognitive deficits.Interestingly,we have observed tau pathology,neuronal apoptosis and necroptosis and brain atrophy,phenotypes rarely seen in other APP models.This App knock-in rat model may serve as a useful tool for AD research,identifying new drug targets and biomarkers,and testing therapeutics. | Keliang Pang Richeng Jiang Wei Zhang Zhengyi Yang Lin-Lin Li Makoto Shimozawa Simone Tambaro Johanna Mayer Baogui Zhang Man Li Jiesi Wang Hang Liu Ailing Yang Xi Chen Jiazheng Liu Bengt Winblad Hua Han Tianzi Jiang Weiwen Wang Per Nilsson Wei Guo Bai Lu | 2022 | Cell Research2022，32，2： | 6 |
| 12 | Design of Vibration Sensor Based on Fiber Bragg Grating显示文摘纤维栅栏是纤维的一种新类型很快在最近的年里在核心的折射索引一直在变化的眼的轻来源设备。特别,它能借助于特殊结构设计和封装技术认识到外部参数的高精确[1, 2 ] 。在这篇论文,对颤动在关键区域监视合适的一个纤维栅栏颤动传感器基于监视系统的颤动的技术背景被设计。传感器使用单个横梁结构并且粘贴纤维布拉格栅栏(FBG ) 在表面上测量颤动波长。当颤动简单地是泛音颤动时,布拉格思考波长将周期性地变化,并且波长曲线的周期的变化能被纤维栅栏解调器测量,然后,试验性的结果的正确性被验证。在这篇论文,通过解调器测量的数据的分析, MATLAB 软件被用来证实数据,和不同频率域,模式,和阶段频率弯被获得。测量范围是 0 Hz-100 Hz,并且自然频率是 90.6 Hz。 | Zhengyi ZHANG Chuntong LIU | 2017 | Photonic Sensors2017，7，4： | 5 |
| 13 | Preparation of Nano-sized Zirconium Carbide Powders through a Novel Active Dilution Self-propagating High Temperature Synthesis Method显示文摘High quality nano-sized zirconium carbide(Zr C) powders were successfully fabricated via a developed chemical active dilution self-propagating high-temperature synthesis(SHS) method assisted by ball milling pretreatment process using traditional cheap zirconium dioxide powder(ZrO2), magnesium powder(Mg) and sucrose(C12H22O11) as raw materials. FSEM, TEM, HRTEM, SAED, XRD, FTIR and Raman, ICPAES, laser particle size analyzer, oxygen and nitrogen analyzer, carbon/sulfur determinator and TG-DSC were employed for the characterization of the morphology, structure, chemical composition and thermal stability of the as-synthesized ZrC samples. The as-synthesized samples demonstrated high purity, low oxygen content and evenly distributed Zr C nano-powders with an average particle size of 50 nm. In addition, the effects of endothermic rate and the possible chemical reaction mechanism were also discussed. | 达奥运 龙飞 WANG Jilin XING Weihong WANG Yang ZHANG Fan 王为民 FU Zhengyi | 2015 | Journal of Wuhan University of Technology(Materials Science)2015，30，4： | 5 |
| 14 | Precise Modulation Strategies for Transcranial Magnetic Stimulation:Advances and Future Directions显示文摘Transcranial magnetic stimulation(TMS)is a popular modulatory technique for the noninvasive diagnosis and therapy of neurological and psychiatric diseases.Unfortunately,current modulation strategies are only modestly effective.The literature provides strong evidence that the modulatory effects of TMS vary depending on device components and stimulation protocols.These differential effects are important when designing precise modulatory strategies for clinical or research applications.Developments in TMS have been accompanied by advances in combining TMS with neuroimaging techniques,including electroencephalography,functional nearinfrared spectroscopy,functional magnetic resonance imaging,and positron emission tomography.Such studies appear particularly promising as they may not only allow us to probe affected brain areas during TMS but also seem to predict underlying research directions that may enable us to precisely target and remodel impaired cortices or circuits.However,few precise modulation strategies are available,and the long-term safety and efficacy of these strategies need to be confirmed.Here,we review the literature on possible technologies for precise modulation to highlight progress along with limitations with the goal of suggesting future directions for this field. | Gangliang Zhong Zhengyi Yang Tianzi Jiang | 2021 | Neuroscience Bulletin2021，37，12： | 4 |
| 15 | Fiber Optic Gyroscope Dynamic North-Finder Algorithm Modeling and Analysis Based on Simulink显示文摘鉴于象更低的自动化水平和传统的纤维的不够的精确那样的问题眼的回转仪(雾) 静电干扰北方查找者,这份报纸集中于 FOG 动态北方查找者原则和算法的深入的分析。点与最少的方形的方法发现算法的 FOG 动态北方的模拟模型用 Simulink 工具箱,然后站台旋转速度和采样频率被建立,它影响动态北方显然发现了精确的雾,被模仿并且计算,并且优化分析作为关键考虑被执行。模拟结果显示出那,当站台旋转速度在 4.5 敨琠浥数慲畴敲ㄠ ? 之间时 ?? 鲵 ??? 徬 ? 蒠?徬銕鴿é t 他 pre 猔? 猔吗?? | Zhengyi ZHANG Chuntong LIU | 2017 | Photonic Sensors2017，7，3： | 4 |
| 16 | Simulation of Fluid Flow, Heat Transfer and Micro-Segregation in Twin-roll Strip Casting of Stainless Steel显示文摘在扔过程的成双转动的长带,在熔融的水池的金属流动和温度分发直接影响这个过程的稳定性和产品的质量。在这篇论文, 3D 联合了热流动的 fenite 元素建模(女性) 为成双转动的长带扔不锈钢的模拟被执行。流的温度和扔的速度在温度地的影响从数字模拟被获得。溶质微分离在长带期间,扔不锈钢的过程也被模仿。一个 developedmicro 分离模型被用来计算在不锈钢的成双转动的扔的溶质微分离。在团结和温度的部分被给的在先令之间的关系,被用来决定 LIT,液体透不过的温度) , ZST (零力量温度) 和在非平衡团结的时期的 ZDT (零韧性温度) 。温度在上的效果微分离被讨论。根据计算结果,在不锈钢扔的成双转动的长带的团结结束温度然后被决定,它能为控制团结结束温度的地点并且分析扔的长带的裂缝提供一个基础。 | Xiaomin ZHANG Zhengyi JIANG Xianghua LIU Guodong WANG | 2006 | Journal of Materials Science & Technology2006，22，3： | 4 |
| 17 | Microstructure and Mechanical Properties of Nb- and Nb+ Ti-Stabilised 18Cr-2Mo Ferritic Stainless Steels显示文摘To explore the optimum use of stabilised elements and study the influences of stabilisation in 18 Cr-2 Mo grades,the Nb and Nb+Ti microalloying investigation focused on the relationships of the microstructure and mechanical properties of the microalloyed 18 Cr-2 Mo ferritic stainless steel thick plates.Thermo-Calc calculation was performed to predict the equilibrium phase diagrams.Afterwards,the microstructure,i.e.grain size and precipitation,of as-annealed specimens was analysed by means of optical microscopy,scanning electron microscopy and transmission electron microscopy,X-ray diffraction and energydispersive spectroscopy.Also,electron backscatter diffraction mapping was constructed to characterise grain boundary.The mechanical properties,including tensile strength and impact toughness,were tested to correlate with the microstructure.The results show that the grain sizes of Nb-stabilised steel are comparatively smaller,which is related to the fine precipitation at the grain boundaries and beneficial to the impact toughness.The increase in its strength is not apparent due to the inhomogeneous grain sizes.The grain boundary characters are similar,which is not the main factor related to their mechanical properties.When Ti is added,TiN forms above the liquidus,and large TiN particles evidently impair impact toughness. | Jian Han Zhixiong Zhu Gang Wei Xingxu Jiang Qian Wang Yangchuan Cai Zhengyi Jiang | 2020 | Acta Metallurgica Sinica(English Letters)2020，33，5： | 4 |
| 18 | Modeling uniaxial tensile deformation of polycrystalline Al using CPFEM显示文摘The crystal plasticity finite element modeling(CPFEM)is realized in commercial finite element code ABAQUS with UMAT subroutine on the basis of the crystal plasticity theory of rate dependent polycrystal constitutive relations in the mesoscopic scale.The initial orientations obtained by electron backscatter diffraction(EBSD)are directly input into the CPFEM to simulate the mechanical response of polycrystaUine 1050 pure Al in uniaxial tensile deformation.Two polycrystal models and two tensile strain rates were used in the simulations.The stress-strain curves of tensile deformation were analyzed.The predictions and the corre- sponding experiment result show reasonable agreement and slight deviation with experiments.The flow true stress of strain rate 0.01 s^(-1)is higher than that of strain rate 0.001 s^(-1).At the strain less than 0.05,the stress saturated rate of the experiment is higher than the simulated results.However,the stress saturated rate of the experiment becomes gentler than the corresponding simulated predictions at the strain over 0.05.Also,necking was simulated by the two models,but the necking strain is not well predicted.Tensile textures at strain 0.25 were predicted at the low strain rate of 0.001 s^(-1).The predictions are in good accord with the experimental results. | Huachun pi Jingtao Han Chuanguo Zhang A. Kiet Tieu Zhengyi Jiang | 2008 | Journal of University of Science and Technology Beijing2008，15，1： | 4 |
| 19 | In-situ synthesis and sintering of mullite glass composites by SPS显示文摘The main subject of this work is an investigation of the effects of heating rate and current on the crystallisation of amorphous precursors in spark plasma sintering(SPS).For this,dry gel of Al_(2)O_(3)-SiO_(2) with a molar ratio of 1:1,was synthesized and sintered in-situ by SPS,and also by hot pressing(HP)for comparison.Phase analysis showed that the only crystalline product in both cases was mullite,whose Al_(2)O_(3) content was lower in the SPS specimens.The microstructures showed a low volume fraction of large mullite fibers in the SPS specimens,whereas a high volume fraction of fine equiaxed grains was present in the HP specimen.The main difference in microstructure between HP and SPS specimens could be explained in terms of the higher heating rate of the SPS specimens.The size of the SPS die also affected the size and aspect ratio of the mullite fibers produced,which might have been due to either the different electrical current required or a difference in specimen temperature profile. | Jinyong ZHANG Hai ZHAN Zhengyi FU Richard TODD | 2014 | Journal of Advanced Ceramics2014，3，2： | 4 |
| 20 | Morphology and formation mechanism of sand shadow dunes on the Qinghai-Tibet Plateau显示文摘The formation and development of dunes depend on wind-blown sand movement which is affected by the characteristics of sand material, topography, wind regimes and other factors. In this paper, we investigated two sand shadow dune groups in Shigatse and Za'gya Zangbo of Tibet and an individual dune in Da Qaidam of Qinghai, and analyzed their topographies and morphologies, and the physical characteristics of the sand, wind regime and sand transport. Formed under harsh conditions behind hills, these mature sand shadow dunes are hundreds of meters long, have significant ridges and crescent dunes downwind, and have a hill pass on one or both sides. Wind tunnel experiments revealed that the hill gap and wind velocity are important factors in the formation of these dunes. Sand shadow dunes formed only when the gap spacing is two-thirds of the hill height. When wind velocities are 20 m/s, the sand body is divided into two parts. The hill pass allows the transport of sand by wind, creating a 'narrow-pipe effect', which causes the transported material to gradually accumulate in the center of the shadow zone. We observed that the following are needed for sand shadow dunes to form:(1) strong winds, sufficient sand, suitable obstacles and a dry climate;(2) one or both sides of the obstacle forming the shadow zone must have a hill pass; and(3) the windward side of the obstacle must have a wide, flat area, providing adequate spacing for wind flow and transport of material and the leeward side must have a sufficiently broad, flat area to allow the release of the transported material. Research results on these newly discovered dunes on the Qinghai-Tibet Plateau could contribute to the understanding of dune geomorphology. | JianHua XIAO JianJun QU ZhengYi YAO YingJun PANG KeCun ZHANG | 2015 | Journal of Arid Land2015，7，1： | 4 |
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