检索结果-南通市图书馆

Comparative investigation of the free radical scavenging potential and anticancer property of Diospyros blancoi(Ebenaceae)

引用

Asian Pacific Journal of Tropical Biomedicine 2016年第5期6卷 410-417页

作者： Muhammad Ali Khan Mahbubur Rahman Nazmul sardar Saiful Islam Arman Badrul Islam Jahangir alam Khandakar Mamunur Rashid Golam Sadik AHM Khurshid alam Department of Pharmacy Bangabandhu Sheikh Mujibur Rahman Science and Technology University Department of Pharmacy University of Rajshahi Drugs and Toxins Research Division Bangladesh Council of Scientific and Industrial Research Product Development and Validation Department Square Pharmaceutical Limited Laboratory of Genetics Graduate School of BiostudiesKyoto University

Objective: To investigate the comparative effects of Diospyros blancoi(Ebenaceae)leaves(DBL), root bark(DBRB) and stem bark(DBSB) on free radicals and ***: The polyphenol contents, antioxidant and free radical scavenging properties were determined using standard spectrophotometric methods. Cytotoxicity and anticancer activities were performed on brine shrimp nauplii and Ehrlich ascite carcinoma cells, ***: Among the extracts, DBSB showed the highest total antioxidant capacity and reducing capacity on ferrous ion. Based on 1,1-diphenyl-2-picrylhydrazyl and hydroxyl radical scavenging activities, DBSB showed(95.760 ± 0.343)% and(67.460 ± 2.641)%scavenging with IC50of(3.10 ± 0.17) and(50.00 ± 3.11) mg/m L, respectively. The IC50 values of standard butylated hydroxytoluene and catechin(CA) for 1,1-diphenyl-2-picrylhydrazyl and hydroxyl radicals were(8.50 ± 0.25) and(75.00 ± 0.14) mg/m L,respectively suggesting that DBSB had a significant(P DBRB > CA > ***, the phenolic [(139.91 ± 3.924) mg gallic acid equivalent/g] and flavonoid contents[(412.00 ± 16.70) mg catechin equivalent/g)] of DBSB were higher than that of other extracts. In addition, the DBSB showed the moderate cytotoxic and anticancer ***: Our results indicate that Diospyros blancoi stem bark had the significant highest antioxidant and free radical scavenging properties as well as moderate anticancer ***, we assume that the anticancer activity of this plant can be, at least in part, attributed to its content in phenolic compounds as well as its significant free radical scavenging properties.

关键词： Diospyros blancoi Free radicals Polyphenols Antioxidant Cytotoxicity Anticancer

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

Relative Time Quantum-based Enhancements in Round Robin Scheduling

引用

Computer Systems Science & Engineering 2022年第5期41卷 461-477页

作者： sardar Zafar Iqbal Hina Gull Saqib Saeed Madeeha Saqib Mohammed Alqahtani Yasser A.Bamarouf Gomathi Krishna May Issa Aldossary Department of Computer Information Systems College of Computer Science and Information TechnologyImam Abdulrahman Bin Faisal UniversityP.O.Box No.1982DammamSaudi Arabia

Modern human life is heavily dependent on computing systems and one of the core components affecting the performance of these systems is underlying operating *** systems need to be upgraded to match the needs of modern-day systems relying on Internet of Things,Fog computing and Mobile based *** scheduling algorithm of the operating system dictates that how the resources will be allocated to the processes and the Round Robin algorithm(RR)has been widely used for *** intent of this study is to ameliorate RR scheduling algorithm to optimize task *** have carried out an experimental study where we have developed four variations of RR,each algorithm considers three-time quanta and the performance of these variations was compared with the RR algorithm,and results highlighted that these variations performed better than conventional RR *** the future,we intend to develop an automated scheduler that can determine optimal algorithm based on the current set of processes and will allocate time quantum to the processes intelligently at the run *** way the task performance of modern-day systems can be improved to make them more efficient.

关键词： CPU scheduling Round Robin enhanced Round Robin relative time quantum operating systems

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

航空发动机宽弦空心风扇叶片制造研究综述

引用

航空动力学报 2023年第11期38卷 2675-2687页

作者：李灿郎利辉 sardar MUHAMMAD I 郭英健张德鑫北京航空航天大学机械工程及自动化学院北京100191

详细介绍了国外航空发动机风扇叶片结构及成形技术的发展与现状,从结构设计、成形工艺以及力学性能领域分析了国内钛合金宽弦空心风扇叶片研究现状。基于宽弦空心风扇叶片服役过程中现存问题,结合扩散焊接/常规塑性/超塑性成形技术,探... 详细信息

详细介绍了国外航空发动机风扇叶片结构及成形技术的发展与现状,从结构设计、成形工艺以及力学性能领域分析了国内钛合金宽弦空心风扇叶片研究现状。基于宽弦空心风扇叶片服役过程中现存问题,结合扩散焊接/常规塑性/超塑性成形技术,探讨了叶片空腔结构设计、成形工艺优化以及扩散焊结构力学性能三大领域的关键技术研究发展方向。结果表明:空腔结构的设计应基于结构轻量化、成形可行性及力学性能最优三大目标展开研究;成形工艺的优化着重开展多工序多目标耦合优化、数值计算精度提高、材料冷热复合加工过程形性演变精确预测与控制等方面的研究;扩散焊结构力学性能的提高应当从复杂载荷条件下焊缝裂纹扩展以及疲劳性能演变等方面展开研究。

关键词：空心风扇叶片扩散焊接超塑性成形结构设计成形工艺力学性能

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

Identification and modelling of applicable wear conditions for stir cast Al-composite

引用

Friction 2020年第5期8卷 847-873页

作者： Santanu sardar Santanu Kumar KARMAKAR Debdulal DAS Department of Mechanical Engineering Indian Institute of Engineering Science and TechnologyHowrah 711103India Department of Metallurgy and Materials Engineering Indian Institute of Engineering Science and TechnologyHowrah 711103India

A comprehensive study of the tribological performance of the Al-Zn-Mg-Cu/Al2O3 composite and its matrix alloy is presented in this paper, with a specific emphasis to identify and model the applicable wear conditions where the composite provides a minimum of 50% reduction in wear rate and 25% lowering of the friction coefficient. Two-body abrasion experiments following Taguchi L27 orthogonal design have been performed separately on alloy and composite materials, both prepared by the stir casting method. The influence of crucial control factors including silicon carbide (SiC) abrasive size, load, sliding distance, and velocity on the percentage variations of wear rates and friction coefficients between alloy and composite have been studied using the analysis of variance technique and full quadratic regression method. The dominant control factors are identified as abrasive size, load, and the interaction between abrasive size and load. This has been verified by establishing the influence of abrasive size and load on variations of wear mechanisms like microcutting, microploughing, and delamination, identified by means of in-depth characterization of worn surfaces and generated debris for both alloy and composite. The selection of applicable tribological condition for the composite has been accomplished by adopting the multi-response optimization technique based on combined desirability approach to obtain concurrent optimization of the percentage variations of wear rates and friction coefficients. Predictive models correlating the superiority of tribological performance of composite with abrasion conditions have been developed, and these are found to be accurate (errors <10%), as determined by confirmatory experiment.

关键词： aluminum matrix composite tribology design of experiment Taguchi multi-response optimization abrasion mechanism

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

Syntheses,Spectral Studies and Bioanalyses of Some Triorganotin(IV) Complexes of Cephlaxine

引用

Chinese Journal of Structural Chemistry 2008年第7期27卷 846-852页

作者： Wajid Rehman Bakhtiar Muhammad Farman Ali sardar Atif Department of Chemistry Hazara University MansehraPakistan

Five novel triorganotin（IV） complexes have been synthesized by refluxing trimethyl, triethyl, tributyl, triphenyl and tribenzyltin chloride with Cephlaxine. These compounds were characterized by spectroscopic （IR, IH, 13C, 119Sn NMR） techniques and elemental analysis. The results obtained through these techniques are in full agreement with the proposed 1：1 stoichiometry. The synthesized compounds were than tested against various microorganisms and fungi. The results of new products obtained showed that the triphenyltin（IV） complex displayed promising activity against all types of bacteria and fungi used while all other compounds showed significant antibacterial and antifungal activity.

关键词： cephlaxine spectra triorganotin activity bacteria

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

Effect of niobium promoter on iron-based catalyst for Fischer-Tropsch reaction

引用

燃料化学学报 2012年第1期40卷 48-53页

作者： sardar ALI Noor Asmawati MOHD ZABIDI Duvvuri SUBBARAO Department of Chemical Engineering Universiti Teknologi PETRONAS Bandar Seri Iskandar 31750 Tronoh Perak Malaysia Department of Fundamental and Applied Sciences Universiti Teknologi PETRONAS Bandar Seri Iskandar 31750 Tronoh Perak Malaysia

Niobium-promoted Fe/CNTs catalysts were prepared using a wet impregnation *** were characterized by nitrogen adsorption,H2-TPR,TPD,XRD and *** Fischer-Tropsch Synthesis(FTS) was carried out in a fixed-bed microreactor at 220 ℃,1 atm and H2/CO=2 for 5 *** of niobium into Fe/CNTs increased the dispersion,decreased the average size of iron oxide nanoparticles and the catalyst ***-promoted Fe catalyst resulted in appreciable increase in the selectivity of C5+ hydrocarbons and suppressed methane *** effects were more pronounced for the 0.04%Nb/Fe/CNTs catalyst,compared to those observed from other niobium *** 0.04%Nb/Fe/CNTs catalyst enhanced the C5+ hydrocarbons selectivity by a factor of 67.5% and reduced the methane selectivity by a factor of 59.2%.

关键词：碳纳米管铌费托合成铁碳氢化合物

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

DFT studies of thermoelectric properties of R-Au intermetallics at 300 K

引用

Journal of Rare Earths 2018年第2期36卷 197-202页

作者： sardar Ahmad Rashid Ahmad Muhammad Bilal Najeeb Ur Rehman Center for Computational Materials Science University of Malakand Department of Chemistry University of Malakand Department of Physics University of Malakand

Thermoelectric and electronic properties of cubic bi-intermetallics R-Au（R = Tb, Ho. Er. Tm and Yb）compounds were explored. Electronic properties i.e. density of states and band structure were computed using first principles calculations which proved the metallic nature of these compounds. Post-DFT（BoltzTraP） calculations were carried out to explore their thermoelectric properties like electrical conductivities. Seebeck coefficient, electronic thermal conductivities and figure of merit. The highest Seebeck coefficient and figure of merit were found for YbAu among these compounds which are 105 μV/K and 0.285 respectively. All the calculations were carried out at 300 K. Large values of figure of merit obtained for these compounds at room temperature indicate that these materials can be used for thermoelectric devices however need experimental verification.

关键词： DFT Seebeck coefficient Figure of merit Thermal conductivity Electrical conductivity R-Au

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

Development of niobium-promoted cobalt catalysts on carbon nanotubes for Fischer-Tropsch synthesis

引用

Journal of Natural Gas Chemistry 2011年第6期20卷 659-663页

作者： sardar Ali Noor Asmawati Mohd Zabidi Duvvuri Subbarao Department of Chemical Engineering Universiti Teknologi PETRONASBandar Seri Iskandar31750 TronohPerakMalaysia Department of Fundamental and Applied Sciences Universiti Teknologi PETRONASBandar Seri Iskandar31750 TronohPerakMalaysia

Cobalt-based catalysts were prepared by a wet impregnation method on carbon nanotubes （CNTs） support and promoted with *** were characterized by nitrogen adsorption,TEM,XRD,TPR,TPO and *** of niobium increased the dispersion of cobalt but decreased the catalysts ***-Tropsch synthesis （FTS） was carried out in a fixed-bed microreactor at 543 K,1 atm and H2/CO=2 for 5 *** of niobium enhanced the C5＋ hydrocarbons selectivity by 39% and reduced methane selectivity by 59%.These effects were more pronounced for 0.04%Nb/Co/CNTs catalyst,compared with those observed for other niobium compositions.

关键词： CNTs cobalt niobium Fischer-Tropsch synthesis

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

Thermomechanical response of aluminum alloys under the combined action of tensile loading and laser irradiations

引用

Chinese Physics B 2018年第3期27卷 469-480页

作者： Mohsan Jelani 李泽文沈中华 Maryam sardar School of Science Nanjing University of Science and Technology Advanced Launching Co-Innovation Centre Nanjing University of Science and Technology

This study reports the investigation of the thermomechanical behavior of aluminum alloys （AI-1060, A1-6061, and A1-7075） under the combined action of tensile loading and laser irradiations. The continuous wave ytterbium fiber laser （wavelength 1080 nm） was employed as the irradiation source, while tensile loading was provided by the tensile testing machine. The effects of various pre-loading and laser power densities on the failure time, temperature distribution, and the deformation behavior of aluminum alloys are analyzed. The experimental results represent the significant reduction in failure time for higher laser power densities and for high preloading values, which implies that preloading may contribute a significant role in the failure of the material at elevated temperature. Fracture on a microscopic scale was predominantly ductile comprising micro-void nucleation, growth, and coalescence. The AI-1060 specimens behaved plastically to some extent, while A1-6061 and A1-7075 specimens experienced catastrophic failure. The reason and characterization of ma- terial failure by tensile and laser loading are explored in detail. A comparative behavior of under-tested materials is also investigated. This work suggests that studies considering only combined loading are not enough to fully understand the mechanical behavior of under-tested materials. For complete characterization, one should consider the effect of heating as well as loading rate and the corresponding involved processes with the help of thermomechanical coupling and the thermal elastic-plastic theory.

关键词： aluminum alloys fiber laser tensile loading thermomechanical effects failure evolution

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

Mathematical Study of A Memory Induced Biochemical System

引用

IEEE/CAA Journal of Automatica Sinica 2018年第6期5卷 1142-1149页

作者： Mithun Kumar Ghosh Tridip sardar Xianbing Cao Priti Kumar Roy Centre for Mathematical Biology and Ecology Department of MathematicsJadavpur University Department of Mathematics Dinabondhu Andrews College College of Science Beijing Technology and Business University

In this work, to study the effect of memory on a bi-substrate enzyme kinetic reaction, we have introduced an approach to fractionalize the system, considering it as a threecompartmental model. Solutions of the fractionalized system are compared with the corresponding integer-order model. The equilibrium points of the fractionalized system are derived analytically. Their stability properties are discussed from numerical aspect. We determine the changes of the substances due to the changes of "memory effect". The effect is discussed critically from the perspective of product formation. We have also analyzed the memory induced system with a control measure in view of optimizing the product. Our numerical result reveals that the solutions of the fractionalized system, when it is free from memory, are in good agreement with the integer-order *** is noticed that the effect of memory influences the reaction in the forward direction and assists in yielding the product more quickly. However, an extensive use of memory makes the system slower, but introduction of a control input makes the reaction faster. It is possible to overcome the slowness of the reaction due to the undue effect of memory by appropriate use of a control measure.

关键词：控制措施记忆诱导系统自动化技术发展现状

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

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

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

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：