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Journal of Materials Science & Technology 2011年第7期27卷 633-640页

作者： c.J. huang c.M. cheng c.P. chou f.h. chen Department of Mechanical Engineering National Chiao Tung University Hsinchu 300 Taiwan China Department of Industrial Education National Taiwan Normal University Taipei 106 Taiwan China

This paper examined the impact of the number of thermal cycles and augmented strain on hot cracking in AZ31 and AZ61 magnesium alloy. Statistical analyses were performed. following observation using a scanning electron microscope （SEM）, an energy dispersive spectrometer （EDS） was used for component analysis. Results showed that Al content in magnesium alloy has an effect on hot cracking susceptibility. In addition, the nonequilibrium solidification process produced segregation in Al content, causing higher liquid Mg-alloy rich Al content at grain boundaries, and resulting into liquefied grain boundaries of partially melted zone （PMZ）. In summary, under multiple thermal cycles AZ61 produced serious liquation cracking. AZ61 has higher （6 wt%） Al content and produced much liquefied Mg17Al12 at grain boundaries under multiple thermal cycles. The liquefied Mg17Al12 were pulled apart and hot cracks formed at weld metal hAZ due to the augmented strain. Since AZ31 had half the Al content of AZ61, its hot-cracking susceptibility was lower than AZ61. In addition, AZ61 showed longer total crack length （TcL） in one thermal cycle compared to that in three thermal cycles. This phenomenon was possibly due to high-temperature gasification of Al during the welding process, which resulted in lower overall Al content. consequently, shorter hot cracks exhibited in three thermal cycles. It was found the Al content of AZ31 and AZ61 can be used to assess the hot-cracking susceptibility.

关键词： Varestraint test Thermal cycles hot-cracking susceptibility Gas tungsten arc welding (GTAW) AZ31 AZ61

Root Exudation of Organic Acids of.herbaceous Pioneer Plants and Their Growth in Sterile and Non-Sterile Nutrient-Poor,Sandy Soils from Post-Mining Sites

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Pedosphere 2019年第1期29卷 34-44页

作者： Katja BOLDT-BURISch Bernd Uwe SchNEIDER M.Anne NAETh Reinhard f.hTTL chair of Soil Protection and Recultivation Brandenburg University of Technology helmholtz centre Potsdam-German Research centre for Geosciences Department of Renewable Resources University of Alberta

Nutrient-poor, sandy soils form the prevailing substrate at post-mining sites of the Lusatian region(Brandenburg, Germany) and present a challenge for vegetation development. We studied the organic acid quantity and composition of three commonly occurring pioneer plant species, the legumes Lotus corniculatus L. and Trifolium arvense L. and the grass calamagrostis epigeios(L.) Roth, to determine if plant growth and exudation differed with(non-sterilized soil) and without(sterilized soil) an indigenous soil microbial community. We investigated whether organic acids were found in the rhizosphere and surrounding soil and whether this influenced nutrient mobilization. This study consists of linked field investigations and a greenhouse experiment. Plants were grown in the greenhouse in either sterilized or non-sterilized sandy soil from a reclamation site in the Lusatian mining landscape(Welzow Su¨d, East Germany). After seven months, the plant biomass, root morphology, organic acids, and water-soluble nutrients and root colonization with arbuscular mycorrhizal fungi(AMf) and dark septate endophytes(DSE) were analyzed. Roots of all three plants in the field and greenhouse experiments were highly colonized with AMf. calamagrostis epigeios and T. arvense had a significantly higher colonization frequency with DSE than L. corniculatus. The quantity and composition of organic acids strongly differed among plant species, with the highest number of organic acids found for L. corniculatus and lowest for c. epigeios. The quantity of organic acids was greatly reduced in all plants under sterilized soil conditions. however, the composition of organic acids and plant growth in sterilized soil were reduced for both legumes, but not for c. epigeios, which had a higher biomass under sterilized conditions. changes in nutrient concentrations in the field rhizosphere soil relative to those in the control were measurable after seven months. While the spectrum of organic acids and the growth

关键词： calamagrostis epigeios indigenous soil microbial community Lotus corniculatus microbial colonization mining landscape nutrient mobilization root symbiotic partner Trifolium arvense

Projected area and drag coefficient of.high velocity irregular fragments that rotate or tumble

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Defence Technology（防务技术） 2017年第4期13卷 269-280页

作者： John f. Moxnes 0yvind fr0 yland Ivar J. 0ye Tom I. Brate Eva friis Gard 0degardstuen Tallak h. Risdal Norwegian Defence Research Establishment Land Systems Division P.O. Box 25 2027 Kjeller Norway Nammo Raufoss AS P.O. Box 162 2831 Raufoss Norway hPVisTech AS Bj0rnstadgutua 21 2092 Minnesund Norway

3 degrees of freedom(DOf)exterior ballistic computer models are used in fragment studies to calculate individual trajectories of each fragment based on drag coefficient and the projected(presented)area in the direction of velocity of center of *** expectation of a randomly distributed projected area is commonly used for fragments that tumble(random rotation)during *** forecast a model where the expected drag coefficient is dependent of shape and Mach *** or tumbling only affects the expected projected *** of projected areas during tumbling and rotation are *** examination of the data by Mc cleskey(1988)indicates that the volume of the fragment to the power of2/3 is a better parameter to characterize the drag coefficient of the fragments than the maximum projected *** simulations are used to verify results and to study projected area and drag coefficient of fragments.

关键词： fragments form factor Mach number Drag coefficient cauchy area Tumbling

combustion synthesis, characterization and luminescence properties of barium aluminate phosphor

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Journal of Rare Earths 2014年第9期32卷 806-811页

作者： A.h. Wako f.B Dejene h.c Swart Department of Physics University of the Free State (Qwaqwa Campus) Department of Physics University of the Free State

The blue-green emitting Eu2＋ and Nd3＋ doped polycrystalline barium aluminate （BaAI204：Eu2＋,Nd3＋） phosphor, was prepared by a solution-combustion method at 500 ℃without a post-annealing process. The characteristic variation in the structural and luminescence properties of the as-prepared samples was evaluated with regards to a change in the Ba/A1 molar ratio from 0.1：1 to 1.4：1. The morphologies and the phase structures of the products were characterized by scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, X-ray diffraction （XRD） and X-ray photoelectron spectroscopy （XPS）, while the optical properties were investigated using ultra-violet （UV） and photoluminescence （PL） spectroscopy, respectively. The XRD and TEM results revealed that the average crystallite size of the BaAl2O4：Eu2＋,Nd3＋ phosphor was about 70 urn. The broad-band UV-excited luminescence of the phosphors was observed at 2max=500 um due to transitions from the 4f^65d1 to the 4f7 configuration of the Eu2＋ ion. The PL results indicated that the main peaks in the emission and excitation spectrum of phosphor particles slightly shifted to the short wavelength due to the changes in the crystal field due to the structure changes caused by the variation in the quantity of the Ba ions in the host lattice.

关键词： BaAl2O4:Eu2+,Nd3+ persistence luminescence Eu2+ and Nd3+ doping rare earths

Maximum Independent Sets and Supervised Learning

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Journal of the Operations Research Society of china 2023年第4期11卷 957-972页

作者： Roberto Montemanni Derek h.Smith Xiao-chen chou Department of Sciences and Methods for Engineering University of Modena and Reggio EmiliaVia Amendola 242122Reggio EmiliaItaly School of computing and Mathematics University of South WalesPontypriddCF371DLWalesUK

The paper discusses an enhancement to a recently presented supervised learning algorithm to solve the Maximum Independent Set *** particular,it is shown that the algorithm can be improved by simplifying the task learnt by the neural network adopted,with measurable effects on the quality of the solutions provided on unseen *** results are presented to validate the idea..

关键词： Maximum clique problem Maximum Independent Set problem Machine learning Graph theory

青光眼患者血清抗视网膜抗原的抗体轮廓质谱分析

维普期刊数据库评论

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中华眼科杂志 2009年第7期45卷 625-630页

作者：严良 Joachim S. c Pfeiffer N Grus f.h Erb c 上海市宝山中心医院眼科 201900 Experimental Ophthalmology Department of Ophthalmology Johannes Gutenberg University Mainz Germany Department of Ophthalmology Schlosspark Klinik Berlin Germany

目的比较原发性开角型青光眼（POAG）患者与正常对照（cTRL）者间的抗体轮廓差异。方法病例对照研究。将44例POAG患者与48例cTRL者的血清分别加入到含有预洗Dyna珠-G蛋白的反应管中，以捕获人免疫球蛋白G（IgG）抗体，形成的IgG—G蛋白... 详细信息

目的比较原发性开角型青光眼（POAG）患者与正常对照（cTRL）者间的抗体轮廓差异。方法病例对照研究。将44例POAG患者与48例cTRL者的血清分别加入到含有预洗Dyna珠-G蛋白的反应管中，以捕获人免疫球蛋白G（IgG）抗体，形成的IgG—G蛋白复合体用来捕获目标抗原（匀质化牛视网膜组织）。经洗提后获得的抗原蛋白通过“表面增强激光解吸附-电离-飞行时间-质谱”仪进行检测。采用Proteomic software project统计学软件，对两组质谱数据连同受检者年龄和性别等参数，自动进行t检验和初步多变量判别分析；随后采用Statistica version8．0统计学软件，进行包括抗原蛋白质谱数据、蛋白质芯片类型和激光解吸附-电离能量等的多变量判别分析。结果cTRL组的平均质谱强度为4244．427±4721．115，POAG组为4049．864±4083．819，两组间差异有统计学意义（f=1．340，P〈0．01）；在POAG患者中，出现了部分高调节免疫反应，但主要表现为低调节免疫反应。结论在POAG患者与cTRL者之间存在明显的抗体轮廓差异，在POAG组中出现的低调节免疫反应表明部分患者可能与“异常免疫”有关。

关键词：青光眼开角型自身免疫自身抗体光谱法质量基质辅助激光解吸电离

Regional ozone pollution and key controlling factors of photochemical ozone production in Pearl River Delta during summer time

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Science china chemistry 2010年第3期53卷 650-662页

作者： chANG chihchung chou c.K.charles Andreas Wahner Research center for Environmental changes Academia SinicaTaipei 11529China forschungszentrum Juelich ICG-Ⅱ:TroposphereJuelichGermany

An intensive field campaign including measurements from the environmental monitoring network and from two super sites took place in the Pearl River Delta region in summer *** routinely measured O3 and NOx concentrations,the spatial and temporal variation of O3 and of the total oxidant concentrations was *** to the spatial variability of NO2/NO,the two super sites were found to be representative of polluted urban and downwind suburban *** addition,both sites were located in high O3 ***-depth diagnostic of photochemical ozone production processes and their key controlling factors are achieved with an observation-based model(OBM) to gain regional *** analysis and sensitivity model runs show that aldehyde and hONO chemistry had significant impacts on local photochemical ozone production *** analysis of calculated Relative Incremental Reactivities shows that photochemical ozone production rates are mainly sensitive to anthropogenic hydrocarbons(hcs) in the polluted urban *** the suburban areas,sensitivity to nitrogen oxide(NO) concentrations *** anthropogenic hcs in both areas are alkenes and *** differences of ozone production efficiencies are identified between the urban and suburban regions,consistent with the OBM diagnosed results.

关键词： ozone Pearl River Delta photochemical ozone productions hONO relative incremental reactivity

Projections of the impacts of climate change on the water deficit and on the precipitation erosive indexes in Mantaro River Basin, Peru

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Journal of Mountain Science 2018年第2期15卷 264-279页

作者： Sly c.WONGchUIG carlos R.MELLO Sin c.chou hydraulics Institute Research Federal University of Rio Grande do Sul Soil and Water Engineering Federal University of Lavras Brazilian Weather Research and forecast National Spatial Research Institute (INPE)

Projections of climate change are essential to guide sustainable development plans in the tropical Andean countries such as Peru. This study assessed the projections of precipitation and potential evaporation, rain erosive potential, and precipitation concentration in the Mantaro River Basin, in the Peruvian Andes, which is important for agriculture and energy production in Peru. We assumed the Intergovernmental Panel on climate change （IPcc） AIB greenhouse gas emission scenario and simulated the global climate change by the hadcM3 global climate model. Due to the steepness of the mountain slopes and the narrowness of the river valley, this study uses the downscaling of the global model simulations by the regional Eta model down to 2o-km resolution. The downscaling projections show decrease in the monthly precipitation with respect to the baseline period, especially during the rainy season, between february and April, until the end of the 21st century. Meanwhile, a progressive increase in the monthly evaporation from the baseline period is projected. The Modified fournier Index （MfI） shows a statistically significant downward trend in the Mantaro River Basin, whieh suggests a possible reduction in the rain erosive potential. The Precipitation concentration Index （PcI） shows a statistically significant increasing trend, which indicates increasingly more irregular temporal distribution of precipitation towards the end of the century. The results of this study allow us to conclude that there should be a gradual increase in water deficit and precipitation concentration. Both changes can be negative for agriculture, power generation, and water supply in the Mantaro River Basin in Peru.

关键词： Precipitation Evaporation Precipitationconcentration Index (PcI) Modified fournier Index(MfI) climate change Tropical Andes

DYNAMIc cOMPAcTION Of PURE cOPPER POWDER USING PULSED MAGNETIc fORcE

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Acta Metallurgica Sinica(English Letters) 2007年第4期20卷 277-283页

作者： h.P. Yu c.f. Li National Key Laboratory for Precision hot Processing of Metals Harbin Institute of Technology Harbin 150001 China

The compaction of pure cu powder was carried out through a series of experiments using dynamic magnetic pulse compaction, and the effects of process parameters, such as discharge energy and compacting direction, on the homogeneity and the compaction density of compacted specimens were presented and discussed. The results indicated that the compaction density of specimens increased with the augment of discharge voltage and time. During unidirectional compaction, there was a density gradient along the loading direction in the compacted specimen, and the minimum compaction density was localized to the center of the bottom of the specimen. The larger the aspect ratio of a powder body, the higher the compaction density of the compacted specimen. And high conductivity drivers were beneficial to the increase of the compaction density. The iterative and the double direction compaction were efficient means to manufacture the homogeneous and high-density powder parts.

关键词： magnetic pulse compaction copper powder compaction density electromagnetic forming