检索结果-南通市图书馆

Journal of Integrative Plant Biology 2005年第11期47卷 1303-1314页

作者： Sheng-Chun XIAO Hong-Lang XIAO Jian-Hua SI Xi-Bin JI fa-min liu Cold and Arid Regions Environmental and Engineering Research Institute the Chinese Academy of Sciences Lanzhou 730000 China

Variation in water resources is a main factor influencing ecohydrological processes and sustainable development in arid regions. Lake level changes are a useful indicator of the variability in water resources. However, observational records of changes in lake levels are usually too short to give an understanding of the long-term variability. In the present study, we investigated the tree rings of shrubs growing on the lakeshore of Lake West-Juyan, the terminus of the Heihe River in western China, and found that Lake West-Juyan had undergone degradation three times over the past 200 years. The lake level decreased from 904.3 to 896.8 m above sea level （a.s.1.） during the period 1800-1900, to 892.0 m a.s.1, from around 1900 to the late 1950s, and the lake dried out in 1963. The trend for changes in lake levels, which was represented by the composite chronology of three beach bars, showed that the phases of increasing lake levels over the past 150 years were during the periods 1852-1871, 1932-1952, 1973-1982, and 1995-1999. Comparison with the history of regional economic development showed that human activity has played an important role in regulating the water resources of the lower reaches of the Heihe watershed over the past 200 years.

关键词： dendrochronology lake degradation events Lake West-Juyan lakeshore shrubs reconstruction of the lake level changes tamarisk.

The centrosymmetric to non-centrosymmetric transformation induced by alkaline-earth cations producing infrared nonlinear optical AeMn_(6)Ga_(6)S_(16)(Ae=Ca,Sr)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Chemistry 2024年第9期67卷 2941-2948页

作者： Yang-Ping Zhang Shao-min Pei Wen-fa Chen Bin-Wen liu Xiao-ming Jiang Guo-Cong Guo State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China Fuzhou 350108China School of Physical Science and Technology Shanghai Tech UniversityShanghai 201210China

Non-centrosymmetric(NCS)structure is an indispensable prerequisite for second-order nonlinear optical(NLO)***,the mainstream approach for designing new NCS structures still relies on chemical substitution,necessitating an urgent infusion of fresh *** this work,two isomorphic sulfides AeMn_(6)Ga_(6)S_(16)(Ae=Ca,1;Sr,2)are afforded by modifying the skeleton of centrosymmetric(CS)Mn_(2)Ga_(2)S_(5) via introducing strong electropositive alkaline-earth ***,the incorporation of Ca^(2+)/Sr^(2+)cations allows the elementary[MnGaS_(9)]_(∞)chains to reconfigure into bumpy[MnS_(6)]-[GaS_(4)]layers in a new engagement manner,thus enabling the conversion from CS to NCS *** modifications cause not only strong second-harmonic generation(SHG)responses(~1.5×benchmark AgGaS_(2)@1,700 nm),but also significantly feasible bandgaps(2.60-2.64 e V)compared to the sulfide Mn_(2)Ga_(2)S_(5)(1.36 e V),which ultimately facilitate ultrahigh laser-induced damage thresholds(4.4-6.6×AgGaS_(2)@1,064 nm for compounds 1 and 2).The present study offers an ingenious approach for the transformation of CS to NCS structure.

关键词： second-harmonic generation non-centrosymmetrical structure NLO functional motif solid-state method

Design of efficient thermoelectric generators

在线全文

学校读者我要写书评

暂无评论

Science China Materials 2024年第1期67卷 377-378页

作者： min liu Yanzhong Pei Interdisciplinary Materials Research Center School of Materials Science and EngineeringTongji UniversityShanghai 201804China

Thermoelectricity,which enables direct conversion between heat and electricity,undergoes impressive developments in recent decades,and is particularly promising for recovering low-grade heat of<600 K[1,2].Currently,only Bi2Te3-based thermoelectric devices are commercialized[3].However,the scarcity of tellurium(Te)(Fig.1a)is the main *** leads to numerous recent efforts on the development of efficient nonBi2Te3 thermoelectrics as potential alternatives,and successful examples(Fig.1b)include Mg3Sb2-alloys[2,3]and MgAgSb[1,2].

关键词： enable efficient electricity

NUDT5 promotes the growth,metastasis,and Warburg effect of IDH wild-type glioblastoma multiforme cells by upregulating TRIM47

在线全文

学校读者我要写书评

暂无评论

Asian Pacific Journal of Tropical Biomedicine 2024年第2期14卷 82-92页

作者： Zi-fa Zhang Shu-ming liu Neurosurgery Department Shanxi Bethune HospitalTaiyuanShanxi Province030022China Shanxi Academy of Medical Sciences TaiyuanShanxi province030022China Emergency Department Taiyuan People’s HospitalTaiyuanShanxi Province030021China

Objective:To explore the regulatory mechanism of NUDT5 in glioblastoma multiforme(GBM).Methods:GEPIA database was used to predict the expressions of NUDT5 and tripartite motif family proteins 47(TRIM47)in GBM ***-qPCR and Western blot analyses were performed to examine NUDT5 expression in GBM ***-229 cell proliferation,migration as well as invasion were estimated by CCK-8,colony formation,wound healing,and Transwell assays following interference with *** assay,L-lactic acid kit,glucose detection kit,and ATP detection kit were applied for the detection of glycolysis-related ***-immunoprecipitation experiment was carried out to verify the relationship between NUDT5 and ***:GEPIA database showed that NUDT5 expression was significantly increased in GBM *** the expression of NUDT5 in GBM cells significantly suppressed the viability,proliferation,invasion,migration,and glycolysis of GBM ***,TRIM47 was highly expressed in GBM cells and interacted with *** of TRIM47 partially reversed the inhibitory effect of NUDT5 downregulation on the proliferation,metastasis,and glycolysis of GBM ***:NUDT5 promotes the growth,metastasis,and Warburg effect of GBM cells by upregulating *** NUDT5 and TRIM47 can be used as targets for GMB treatment.

关键词： Glioblastoma multiforme NUDT5 TRIM47 Growth Metastasis Warburg effect

Intelligent casting:Empowering the future foundry industry

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

China Foundry 2024年第5期21卷 409-426页

作者： Jin-wu Kang Bao-lin liu Tao Jing Hou-fa Shen School of Materials Science and Engineering Key Laboratory for Advanced Materials Processing TechnologyTsinghua UniversityBeijing 100084China

Emerging technological advances are reshaping the casting sector in latest *** technology is evolving towards intelligent casting paradigm that involves automation,greenization and intelligentization,which attracts more and more attention from the academic and industry *** this paper,the main features of casting technology were briefly summarized and forecasted,and the recent developments of key technologies and the innovative efforts made in promoting intelligent casting process were ***,the technical visions of intelligent casting process were also put *** key technologies for intelligent casting process comprise 3D printing technologies,intelligent mold technologies and intelligent process control *** future,the intelligent mold that derived from mold with sensors,control devices and actuators will probably incorporate the Internet of Things,online inspection,embedded simulation,decision-making and control system,and other technologies to form intelligent cyber-physical casting system,which may pave the way to realize intelligent *** is promising that the intelligent casting process will eventually achieve the goal of real-time process optimization and full-scale control,with the defects,microstructure,performance,and service life of the fabricated castings can be accurately predicted and tailored.

关键词： intelligent casting 3D printing intelligent mold process control cyber-physical casting system embedded simulation

Effects of diamond particle size on microstructure and properties of diamond/Al-12Si composites prepared by vacuum-assisted pressure infiltration

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

China Foundry 2024年第4期21卷 360-368页

作者： Jia-ping Fu Can-xu Zhou Guo-fa Mi Yuan liu School of Materials Science and Engineering Henan Polytechnic UniversityJiaozuo 454100HenanChina School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China Key Laboratory for Advanced Materials Processing Technology Ministry of EducationBeijing 100084China

Diamond/aluminium composites have attracted attention in the field of thermal management of electronic packaging for their excellent *** order to solve the interfacial problem between diamond and aluminium,a novel process combining pressure infiltration with vacuum-assisted technology was proposed to prepare diamond/aluminum *** effect of diamond particle size on the microstructure and properties of the diamond/Al-12Si composites was *** results show that the diamond/Al-12Si composites exhibit high relative density and a uniform *** thermal conductivity and coefficient of thermal expansion increase with increasing particle size,while the bending strength exhibits the opposite *** the average diamond particle size increases from 45μm to 425μm,the thermal conductivity of the composites increases from 455 W·m^(-1)·K^(-1)to 713 W·m^(-1)·K^(-1)and the coefficient of thermal expansion increases from 4.97×10^(-6)K^(-1)to 6.72×10^(-6)K^(-1),while the bending strength decreases from 353 MPa to 246 *** research demonstrates that high-quality composites can be prepared by the vacuum-assisted pressure infiltration process and the thermal conductivity of the composites can be effectively improved by increasing the diamond particle size.

关键词： diamond/aluminum composites thermal conductivity electronic packaging vacuum-assisted pressure infiltration

A New Class of Strong Orthogonal Arrays of Strength Three

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2024年第3期37卷 1233-1250页

作者： WANG Chunyan liu min-Qian YANG Jinyu Center for Applied Statistics and School of Statistics Renmin University of ChinaBeijing 100872China School of Statistics and Data Science LPMC&KLMDASRNankai UniversityTianjin 300071China

Strong orthogonal arrays(SOAs) were recently introduced and studied as a class of spacefilling designs for computer experiments. To surely realize better space-filling properties, SOAs of strength three or higher are desirable. In addition, orthogonality is also an important property for designs of computer experiments, because it guarantees that the estimates of the main effects are uncorrelated. This paper first provides a systematic study on the construction of(nearly) orthogonal strength-three SOAs with better space-filling properties. The newly proposed strength-three SOAs enjoy almost the same space-filling properties of strength-four SOAs, and can accommodate much more columns than the latter. Moreover, they are(nearly) orthogonal and flexible in run sizes. The construction methods are straightforward to implement, and their theoretical supports are well established. In addition to the theoretical results, many designs are tabulated for practical needs.

关键词： Computer experiment orthogonality space-filling property strong orthogonal array

Enhancing corn stalk-based anaerobic digestion with different types of zero-valent iron added during the acidification stage:Performance and mechanism

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2024年第11期145卷 64-74页

作者： Xiang liu Yue liu min Wang Qianzhen Deng Hao Yang College of Agricultural Science and Engineering Hohai UniversityNanjing 210098China State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing 100084China National and Local Joint Engineering Research Center of Ecological Treatment Technology for Urban Water Pollution Wenzhou UniversityWenzhou 325035China Anhui Provincial Key Laboratory of Environmental Pollution Control and Resource Reuse Anhui Jianzhu UniversityHefei 230009China

Anaerobic digestion has been defined as a competitive approach to facilitate the recycling of corn ***,few studies have focused on the role of direct interspecies electron transfer(DIET)pathway in the acidification stage under the addition of different particle sizes of zero-valent iron(ZVI).In this study,three types of ZVI,namely iron filings,iron powder and nanoscale iron,were investigated,respectively,to enhance its high-value *** in volatile fatty acids(Vfas)and methane(CH4)production associated with the underlyingmechanisms were emphatically *** indicated that the addition of ZVI could increase the concentration of Vfas,with the most outstanding performance observed with the use of nanoscale ***,the conversion of propionic acid to acetic acid was driven by adding ZVI with no between-group differences in acidizing ***,the substrate was more fully utilized when supplied with iron powder compared with other groups in methanogenic phase,thereby displaying the maximumCH4 yield with a value of 263.1 mL/(g total solids(TS)).However,adding nanoscale iron could signally shorten the digestion time(T80),saving 7 days in comparison to the group of iron powder.

关键词： Zero-valent iron Corn stalk Anaerobic digestion Volatile fatty acids Methane

An Approximation Algorithm Based on Seeding Algorithm for Fuzzy k-Means Problem with Penalties

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of the Operations Research Society of China 2024年第2期12卷 387-409页

作者： Wen-Zhao liu min Li School of Mathematics and Statistics Shandong Normal UniversityJinan 250014ShandongChina

As a classic NP-hard problem in machine learning and computational geometry,the k-means problem aims to partition the given dataset into k clusters according to the minimal squared Euclidean *** from k-means problem and most of its variants,fuzzy k-means problem belongs to the soft clustering problem,where each given data point has relationship to every center *** to fuzzy k-means problem,fuzzy k-means problem with penalties allows that some data points need not be clustered instead of being paid *** this paper,we propose an O(αk In k)-approximation algorithm based on seeding algorithm for fuzzy k-means problem with penalties,whereαinvolves the ratio of the maximal penalty value to the minimal ***,we implement numerical experiments to show the effectiveness of our algorithm.

关键词： Approximation algorithm Seeding algorithm Fuzzy k-means problem with penalties

Effect of operating conditions on the performance of riser reactor for oxidative coupling of methane Author links open overlay panel

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2024年第8期91卷 235-248页

作者： min Cai Shuangzhu Kong Mengxi liu Chunxi Lu State Key Laboratory of Heavy Oil Processing China University of PetroleumBeijing102249China

Oxidative coupling of methane(OCM)is characterized by high temperature and strong heat released.A riser reactor is designed for the OCM process to improve gas-solid contacting and heat *** work illustrates the effect of hydrodynamic conditions and feed gas composition on the performance of an OCM riser *** findings suggest that oxidative reactions predominantly occur within the acceleration zone and developed flow ***,at the low superficial gas velocity accompanied by a high solid circulating rate,the C_(2)yield initially increases in the acceleration zone,followed by a decrease in the developed flow zone and deceleration *** optimal operating conditions are a specific region corresponding to the solids holdup ranges from 0.015 to ***,the C_(2)yield can be elevated using an appropriate feed mixture.

关键词： Oxidative coupling of methane Riser Hydrodynamics Solids holdup