检索结果-南通市图书馆

Journal of Forestry Research 2022年第2期33卷 475-486页

作者： Peng Meng jing liu Xuefeng Bai Qingdao Agricultural University Qingdao 266109People’s Republic of China Liaoning Province Sand-Fixation and Afforestation Research Institute Fuxin 123000People’s Republic of China

With changes in global climate and land use,the area of desertified farmland in southeastern Horqin Sandy Land(HSL)has increased in recent years,and farmlands are being *** abandoned farmlands(AFs)nega-tively impact the local ***,the aim of the present study was to select suitable trees and shrubs for those AFs to prevent and control the desertification *** this study,three AFs were fenced for 2 years,then 37 arbor and shrub species or varieties of 21 families were planted in the fenced AFs and grown for 10 *** ecological adaptability of the species was evaluated and ranked using a principal component *** results showed that the biodiversity of the AFs significantly improved after 2 years of fencing;the Shannon-Wiener index and species rich-ness of perennial grasses and forbs were 1.45 and 3.6 times higher,respectively,than for the unfenced *** all species planted in fenced AFs,nine tree species had posi-tive comprehensive F(CF)values;Pinus sylvestris(Russian Shira steppe provenance),Populus alba‘Berolinensis’and Gleditsia triacanthos had CF greater than 1,and the first(PC1),second(PC2)and third(PC3)principal component values(F_(1),F_(2),F_(3))were all *** the shrubs,only Lespedeza bicolor and Rosa xanthina *** had CF greater than *** these results suggest that fencing improves biodiversity and that planting trees and shrubs that have higher CF values on the basis of fencing is an effective way to green and beautify AFs in HSL.

关键词： Horqin Sandy Land Fenced abandoned farmland Principal component analysis Tree species selection

Calcium sulfate whisker prepared by flue gas desulfurization gypsum:A physical–chemical coupling production process

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2020年第8期28卷 2221-2226页

作者： jing Gao Qiang Li Fuli liu College of Mining Liaoning Technical UniversityFuxin 123000China CAS Key Laboratory of Green Process and Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China College of Chemical and Environmental Engineering China University of Mining and TechnologyBeijing 100083China

In this paper,the solid waste desulfurization gypsum produced by coal-fired power plants was used as a raw material to prepare calcium sulfate whiskers with high application *** sulfate whiskers with uniform morphology and high aspect ratio can be prepared by hydrothermal method in sulfuric acid solution.A new process of desulfurization gypsum activated by high-energy grinding to reduce the reaction temperature and sulfuric acid concentration was *** the comparison of product morphology,the best grinding time was determined to be 3.5 *** mechanism of desulfurization gypsum through physical–chemical coupling to reduce energy consumption was *** activation of desulfurization gypsum by grinding and the acidic environment provided by the sulfuric acid solution made the calcium sulfate solution reached rapid saturation and accelerated the nucleation *** calculating the conversion and crystallization rate of calcium sulfate whiskers,it was found that there were obvious"autocatalytic"kinetic characteristics during the crystallization process.

关键词： Flue gas desulfurization gypsum Calcium sulfate whiskers Crystallization kinetic Physical–chemical coupling

在线全文

学校读者我要写书评

暂无评论

胰腺疾病体外细胞模型研究进展

中国药理学通报 2025年第1期41卷 23-29页

作者：朱卫丰彭立军刘婧彭淑红江西中医药大学现代中药制剂教育部重点实验室 2.江西中医药大学药学院3.江西中医药大学中医基础理论分化发展研究中心4.江西省中医病因生物学重点实验室江西南昌330004

不健康的饮食、吸烟、饮酒会引起多种胰腺疾病,包括胰腺炎、糖尿病和胰腺癌等,严重威胁人体健康。构建体外细胞模型在研究胰腺疾病的病因病机及其药物的开发及筛选中具有重要意义。目前,国内外学者已开发出多种体外胰腺疾病模型。该文... 详细信息

不健康的饮食、吸烟、饮酒会引起多种胰腺疾病,包括胰腺炎、糖尿病和胰腺癌等,严重威胁人体健康。构建体外细胞模型在研究胰腺疾病的病因病机及其药物的开发及筛选中具有重要意义。目前,国内外学者已开发出多种体外胰腺疾病模型。该文概括了常见胰腺疾病的体外细胞模型,并从模型细胞的特性、培养方式、造模方式、评价指标等方面进行综述,以期为胰腺疾病相关研究人员提供参考。

关键词：胰腺疾病细胞模型细胞特性培养方式造模方法评价指标

A comparative study of network robustness measures

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Computer Science 2017年第4期11卷 568-584页

作者： jing liu Mingxing ZHOU Shuai WANG Penghui liu Key Laboratory of intelligent Perception and Image Understanding of Ministry of Education Xidian University Xi'an 710071 China

The robustness is an important functionality of networks because it manifests the ability of networks to resist failures or attacks. Many robustness measures have been proposed from different aspects, which provide us various ways to evaluate the network robustness. However, whether these measures can properly evaluate the network robustness and which aspects of network robustness these measures can evaluate are still open questions. Therefore, in this paper, a thorough introduction over attacks and robustness measures is first given, and then nine widely used robustness mea- sures are comparatively studied. To validate whether a robustness measure can evaluate the network robustness properly, the sensitivity of robustness measures is first studied on both initial and optimized networks. Then, the performance of robustness measures in guiding the optimization process is studied, where both the optimization process and the ob- tained optimized networks are studied. The experimental re- suits show that, first, the robustness measures are more sen- sitive to the changes in initial networks than to those in op- timized networks; second, an optimized network may not be useful in practical situations because some useful function- alities, such as the shortest path length and communication efficiency, are sacrificed too much to improve the robustness; third, the robustness of networks in terms of closely corre- lated robustness measures can often be improved together. These results indicate that it is not wise to just apply the opti- mized networks obtained by optimizing over one certain robustness measure into practical situations. Practical requirements should be considered, and optimizing over two or more suitable robustness measures simultaneously is also a promising way.

关键词： scale-free network malicious attack robustnessmeasure hill climbing algorithm

A twisted quantum toroidal algebra

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Mathematics in China 2013年第5期8卷 1117-1128页

作者： Naihuan jing Rongjia liu School of Sciences South China University of Technology Guangzhou 510640 China Department of Mathematics North Carolina State University Raleigh NC 27695 USA

As an analog of the quantum TKK algebra, a twisted quantum toroidal algebra of type A1 is introduced. Explicit realization of the new quantum TKK algebra is constructed with the help of twisted quantum vertex operator... 详细信息

关键词： Vertex operator toroidal algebra quantum algebra

Liquid phase 3D printing for quickly manufacturing conductive metal objects with low melting point alloy ink

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(Technological Sciences) 2014年第9期57卷 1721-1728页

作者： WANG Lei liu jing Beijing Key Laboratory of CryoBiomedical Engineering and Key Laboratory of Cryogenics Technical Institute of Physics and Chemistry Chinese Academy of Sciences Department of Biomedical Engineering School of Medicine Tsinghua University

Conventional 3D metal printings are generally time-consuming as well as lacking of high performance printable *** an alternative way,here we proposed the method of liquid phase 3D printing for quickly making conductive metal *** introducing metal alloys whose melting point is slightly above room temperature as printing inks,several representative structures spanning from one,two and three dimension to more complex patterns were demonstrated to be quickly *** with the air-cooling in a conventional 3D printing,the liquid-phase-manufacturing offers a much higher cooling rate and thus significantly improves the speed in fabricating the target metal *** unique strategy also efficiently prevents the liquid metal inks from air oxidation,which is hard to avoid otherwise in an ordinary 3D *** key physical factors(such as properties of the cooling fluid,air pressure within the syringe barrel and needle diameter,types and properties of the printing ink)and several interesting intermediate fluids interaction phenomena between liquid metal and conventional cooling fluids such as water or ethanol,which evidently affecting the printing quality,were *** addition,a basic route to make future liquid phase 3D printer incorporated with both syringe pump and needle arrays was also *** liquid phase 3D printing,which owns potential values not available in a conventional method,opens an efficient way for quickly making conductive metal objects in the coming time.

关键词： liquid phase 3D printing liquid metal printer rapid prototyping low melting point metal liquid cooling oxidation

Compatible hybrid 3D printing of metal and nonmetal inks for direct manufacture of end functional devices

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2014年第11期57卷 2089-2095页

作者： WANG Lei liu jing Beijing Key Laboratory of CryoBiomedical Engineering and Key Laboratory of Cryogenics Technical Institute of Physics and ChemistryChinese Academy of Sciences Department of Biomedical Engineering School of Medicine Tsinghua University

The currently available 3D printing still cannot simultaneously deal with the metal and nonmetal inks together due to their huge difference in the melting points and poor compatible printability between each other. Here through introducing the low melting point alloy Bi35In48.6Sn16Zno.4 and silicone rubber as functional inks, we proposed a compatible hybrid 3D printing method for manufacturing the desired device, the supporting substrate and the allied package structure together. The principle of pneumatic-typed 3D printing of multiple inks was described and typical physical properties of the ink Bi35In48.6Sn16Zno.4 were measured. Several key factors dominating the printing quality such as the temperature of the printing head, the air pressure exerted upon the liquid metal ink in the syringe, the moving velocity and the height of the printing head etc. were clarified. A general way of directly printing out 3D structured electronic devices consisting of both metal and nonmetal materials was demonstrated. Such hybrid objects were patterned and formed up layer by layer with Bi35In48.6Sn16Zno.4 alloy and silicone rub- ber which would become solidified after standing for a period of time under room temperature. To illustrate the compatible printability of these printing inks, a three-layer tricolor LED stereo circuit with controlled lighting capability was further man- ufactured and evaluated. The present study opens an important hybrid 3D printing way for directly manufacturing functional and structural end devices in an easy and low cost way.

关键词： liquid metal ink hybrid 3D printing compatible manufacture electronic device stereo circuit

A NEW WELL TEST MODEL FOR A TWO-ZONE LINEAR COMPOSITE RESERVOIR WITH VARIED THICKNESSES

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2010年第6期22卷 804-809页

作者： ZHANG Lie-hui GUO jing-jing liu Qi-guo State Key Laboratory of Reservoir Geology and Exploitation Southwest Petroleum University Chengdu 610500China

This article presents a new well test model for two-zone linear composite reservoirs, where the rock and fluid properties as well as the formation thicknesses on both sides of the discontinuity are distinctly different. An analytical solution of pressure-transient behavior for a line-source, constant-rate well in this type of reservoir configuration is obtained with Fourier space transformation and Laplace transformation. By applying Duhamel principle, the wellbore storage and skins effects can easily be included. A set of type curves are generated and the sensitivities of the relevant parameters are discussed. A new correlating parameter MhDl√ηD is proposed to identify the pressure response in the pressure derivative curve. The model as well as the corresponding type curves are quite general that they are useful in predicting the production performance or analyzing the production data from this type of well-reservoir systems.

关键词： non-uniform thickness linear composite well test model type curve

Facile interconversions of topology and aromaticity of expanded porphyrin in solution

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2014年第10期57卷 1369-1374页

作者： liu Zeyu MA jing Key Laboratory of Mesoscopic Chemistry Ministry of Education School of Chemistry and Chemical Engineering Nanjing University Sericultural Research Institute Jiangsu University of Science and Technology

The dynamic transformations of conformations and aromatic properties of [32]octaphyrins（1.***.1.0.1.***.1.0） through rotating the pyrrolic ring of the macrocycles are demonstrated by theoretical simulations in CH2Cl2 solution. Facile multistep isomeriza- tions involving antiaromatic-Htickel and aromatic-Mobius topologies were also predicted by density functional theory （DFT）. The understanding of changes in topologies and aromaticities of free-base expanded porphrins may provide useful information to build new macrocycles with unique properties.

关键词： theoretical investigation expanded porphyrin conformational interconversion aromaticity

Two Matrix Theorems Arising from Nilpotent Groups

在线全文

学校读者我要写书评

暂无评论

Algebra Colloquium 2024年第3期31卷 499-504页

作者： jing Zhao Heguo liu School of Mathematics and Statistics Hainan University Haikou 570228China

For a nilpotent group G without π-torsion,and x,y ∈ G,if x^(n)=y^(n) for a T-number n,then x=y;if x^(m)y^(n)=y^(n)x^(m) for n-numbers m,n,then xy=*** is a wellknown result in group *** this paper,we prove two analogous theorems on matrices,which have independence ***,let m be a given positive integer and A a complex square matrix satisfying that(i)all eigenvalues of A are nonnegative,and(i)rank A^(2)=rank A;then A has a unique m-th root X with rank X^(2)=rank X,all eigenvalues of X are nonnegative,and moreover there is a polynomial f(λ)with X=f(A).In addition,let A and B be complex n×n matrices with all eigenvalues nonnegative,and rank A^(2)=rank A,rank B^(2)=rank B;then(i)A=B when A^(r)=B^(r) for some positive integer r,and(i)AB=BA when A^(s)B^(t)=B^(t)A^(s) for two positive integers s and t.

关键词： nilpotent group root matrix Chinese remainder theorem