检索结果-南通市图书馆

Nucleation of Boron-Nitrogen on Transition Metal Surface:A First-Principles Investigation

Chinese Journal of Chemical Physics 2018年第3期31卷 335-340,368页

作者： dildar ahmed Erjun Kan Department of Applied Physics and Institution of Energy and MicrostructureNanjing University of Science and TechnologyNanjing 210094China

Boron nitrogen(BN)monolayer has attracted considerable attention because of their suc-cessful incorporation with graphene based nanodevices.However,many important aspects of the growth mechanisms are still not well explored.Using density functional theory(DFT)calculations,we found that Cu(111)surface is more suitable to be used as a substrate to grow BN monolayer compared with Ni(111)surface.Moreover,we explored that one-dimensional(1D)BN chain configuration is dominant to the two-dimensional(2D)BN ring formation from one pair to five BN pairs deposited on Cu(111)surface.Energetically stable structure transformation of BN monolayer from 1D BN chain to 2D BN ring occurs when the number of pairs is n>5.It is suggested that,as the number of BN pairs increases the energetically stable structures achieve.

关键词： Growth mechanism Density functional theory BN monolayer

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Lipase inhibitory activity of Lagenaria siceraria fruit as a strategy to treat obesity

引用

Asian Pacific Journal of Tropical Medicine 2017年第3期10卷 285-290页

作者： Maria Maqsood dildar ahmed Iqra Atique Wajeeha Malik Department of Chemistry Forman Christian College(A Chartered University)LahorePakistan

Objective:To explore pancreatic lipase inhibitory activity under different extraction conditions in order to track the most potent extract.Methods:The methanolic extract and its fractions in solvents of increasing polarity,ether,chloroform,ethyl acetate,n-butanol and water,were made through cold maceration.Extracts in ethanol,ethyl acetate,acetone and chloroform were similarly prepared.Aqueous extract was prepared through hot decoction method.A reported method was used to determine lipase inhibitory activity of extracts and fractions over wide ranges of concentrations.Results:The extracts and fractions exhibited concentration dependent activity.The IC50(μg/mL)values of methanolic,ethanolic,chloroform,ethyl acetate,acetone,ethyl acetate(after washing with water)and aqueous decoction were 293.40,266.47,157.59,182.12,352.34,257.00,and 190.00,respectively.The activity of chloroform,ethyl acetate and aqueous extracts were close to that of the drug orlistat(IC50 146μg/mL).Out of the fractions of the methanolic extract,the chloroform fraction was most active(IC50 189.6μg/mL).The order of inhibitory activity of the fractions was as follows:chloroform>ether>n-butanolic>aqueous>ethyl acetate.The GC/MS analysis of the most active chloroform faction showed the presence of hexadecanoic acid,methyl hexadecanoate,isopropyl palmitate,methyl 9,12-octadecadienate,and methyl 9,12,15-octadecatrienoate.Conclusions:The study suggests that Lagenaria siceraria has potential to inhibit pancreatic lipase activity,suppressing lipid digestion and thereby diminishing entry of lipids into the body.Regular intake of aqueous decoction of the fruit may therefore be recommended for control of obesity.Fatty acids and their esters may play role as inhibitors of lipase.

关键词： Lagenaria siceraria Obesity Lipase inhibitory activity Bottle gourd

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Antimicrobial activities of methanolic extract of Carissa opaca roots and its fractions and compounds isolated from the most active ethyl acetate fraction

引用

Asian Pacific Journal of Tropical Biomedicine 2015年第7期5卷 533-537页

作者： dildar ahmed Ramsha Saeed Nasir Shakeel Khaizran Fatima Aneela Arshad Department of Chemistry Forman Christian College (A Chartered University) Microbiology Lab Pharmagen Lahore Pakistan

Objective: To study the antibacterial and antifungal activities of methanolic extract of roots of Carissa opaca and its fractions in hexane, chloroform, ethyl acetate, n-butanol and water, and the isolated compounds.Methods: The zones of inhibition of the samples against test microorganisms were determined by agar well diffusion method. Minimum inhibitory concentrations of the samples were determined by agar well dilution method. Test microorganisms included four standard bacteria [Bacillus subtilis ATCC 6633(B. subtilis), Escherichia coli ATCC 8739(E. coli), Pseudomonas aeruginosa ATCC 9027(P. aeruginosa), and Staphylococcus aureus ATCC 6538], two standard fungi [Candida albicans ATCC 10231(C. albicans)] and Aspergillus niger, and six clinical isolates(B. subtilis, E. coli, P. aeruginosa, Staphylococcus aureus, Salmonella typhi and Enterobacter cloacae). The most active fraction was investigated to isolate compounds. The chemical compounds isolated from the ethyl acetate fraction were identified by gas chromatography-mass spectrometer, high performance liquid chromatography and liquid chromatography-mass spectrometer.Results: E. coli, P. aeruginosa, and C. albicans were the most susceptible. Less polar fractions exhibited stronger efficacy than polar ones, and ethyl acetate fraction proved to be the most potent. Zones of inhibition of hexane, chloroform and ethyl acetate fractions, and amoxil against C. albicans were 19.96, 22.01, 23.10 and 19.20 mm, respectively. Ethyl acetate faction was the most toxic to all the test microorganisms, with minimum inhibitory concentrations of 8.0, 7.8 and 7.78 μg/m L against P. aeruginosa, C. albicans and B. subtilis, respectively. Isolated compounds, limonene, 2'-hydroxyacetophenone, vanillin, naphthalenone, 2,3,3-trimethyl-2-(3-methylbuta-1,3-dienyl)-6-methylenecyclohexanone, 2-benzenedicarboxylic acid, mono(2-ethylhexyl) ester, β-sitosterol, vitamin E, rutin, quercetin, lupeol, epigallocatechin, showed considerable antimicrobial activities against test microorganisms.Conclus

关键词： Carissa opaca Antibacterial Antifungal Bioactive compounds

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Theoretical Studies of Some Two-Dimensional Materials

Theoretical Studies of Some Two-Dimensional Materials

引用

作者： ahmed dildar 南京理工大学

学位级别：硕士

One of the purposes of theoretical physics is to achieve certain functional materials to satisfy the increasing demands of human being for future potential applications.Nowadays,with the rapid development of science and the enhancement in living standards,most traditional materials can hardly satisfy people’s needs.Thus the development of new materials has received more and more attention.Computational and theoretical physics is a branch of physics in the twenty-first century and the basis of future nano-devices.The two-dimensional（2D）materials,which have only one or several layers of atoms such as graphene,h-BN,MoS2 monolayer,have received extensive attention because of their unique and outstanding properties.However,up to now,the research on 2D materials are still in the infant stage.Many interesting physical phenomena in 2D systems have not been properly understood yet.Because of the development of computational physics,theoretical physics and computational materials science,now we are able to explain,predict and control the properties of materials and design more ideal new materials on the basis of first-principles calculation and statistic mechanics.These studies will be helpful in the future theoretical and experimental research,and gradually make the value of 2D materials in the future applications of daily life.Chapter one of this thesis briefly introduce and describe the development of computational physics,theoretical physics,and computational materials science,their positions in the modern physics and material science and their importance in the research field of 2D materials.Then we introduce several specific 2D systems,such as graphene,porous graphene,hexagonal boron nitride,group IV alkenes and transition metal halides.Also discuss several important physical properties of 2D systems,such as gas separation,magnetism,quantum spin Hall effect,quantum anomalous Hall effect and multiferroics.Chapter two of this thesis briefly introduce and describe the major methods used in the computational physics and

关键词：二维材料密度泛函理论蒙特卡罗模拟物理性质

来源：

同方学位论文库评论

在线全文

同方学位论文库

学校读者我要写书评

暂无评论

Clustering and Mixed Integer Linear Programming for Rebalancing Problem of Dockless Sharing Bicycles

Clustering and Mixed Integer Linear Programming for Rebalanc...

引用

作者： dildar ahmed（迪达）东南大学

学位级别：硕士

Bike sharing systems without docking stations have got much popularity and rapidly growing in today’s era and becoming an integral part of green Transportation systems but in parallel,it raises severe management and rebalancing issues,which are becoming a challenge in their development and sustainability.Bicycles availability and shortages are in direct relation with the user satisfaction level.A uniform distribution of bicycle inventories over a network of zones to achieve optimal inventories with minimum cost is mainly focussed in this study.Rebalancing problem of dockless sharing bicycle’s systems is addressed in two stages.In the first stage,the randomly scattered bicycles positions are traced out in an area where rebalancing activity will take place and then further divided them into several groups or clusters of either surplus or deficit ones through the clustering technique of K-means clustering algorithm which is a distance-based algorithmic approach that minimizes the distance of bicycles and assigned bicycle to cluster.These clustering and collection mechanism will develop the supply and demand level in each zone which could be thoroughly manipulated before starting the main truck rebalancing operation among zones.In the 2

关键词： Clustering K-means algorithm vehicle routing problem Pick-up and delivery

来源：

同方学位论文库评论

在线全文

同方学位论文库

学校读者我要写书评

暂无评论

Growth Performance,Physicochemical Properties of Meat of Broiler Chicken’s Supplemented with Bacillus pumilus

引用

Journal of Zoological Research 2021年第4期3卷 12-18页

作者： Masroor Ali Bughio Uroosa Majeed Gulfam Ali Mughal Ghulam Shabir Barham dildar Hussain Kalhoro Mansoor Tariq Samo Shoaib ahmed Pirzado Postgraduate Laboratory of Animal Nutrition Department of Animal NutritionSindh Agriculture University TandojamSindh70060Pakistan

This study examined that the efficiency of Bacillus pumilus(BP)on growth performance and meat quality of broiler chickens.A total of day old 240 male broiler chicks were purchased from local hatchery Hyderabad.The chicks were allocated into four groups with six replicates of 10 birds in each replicate.Four diets were prepared for experiment,which included control as basal diet,BP-0.1(CONT+0.1%BP),BP-0.2(CONT+0.2%BP)and AGP(CONT+zinc bacitracin 20 ppm)as antibiotic growth promotor.The results showed that live body weight(LBW),average daily gain was recorded higher(P<0.01)in birds fed diet with BP-0.1 than control and BP-0.2 groups,as well as ADFI also increased in BP-0.1 than control group.BP-0.1 supplementation significantly reduced feed conversion ratio(FCR)than other groups(P<0.01).Both moisture and crude protein(CP)content influenced by supplementation of BP-0.1 than other groups.However,birds fed diet with BP-0.1 had least fat content in breast meat compared with the other groups(P<0.01).In addition,BP-0.1probiotic-fed birds had the lowest(P<0.01)pH,cooking loss(CL)and drip loss(DL)as compared to control,BP-0.2 and AGP groups.The water holding capacity(WHC)were found higher in BP-0.1 as compared to other groups(P<0.01).In conclusion,Bacillus pumilus probiotic supplementation is a promising approach for substitution of antibiotics in broiler diet for enhancement of growth performance and physiochemical properties of meat.

关键词： Growth performance Meat quality Bacillus pumilu Probiotics Broilers

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：