检索结果-南通市图书馆

Shrinking greenery： Land use and land cover changes in Kurram Agency, Kohi Safid Mountains of north-western Pakistan

引用

Journal of Mountain Science 2018年第2期15卷 296-306页

作者： kamal HUSSAIN Fazlul HAQ Fazlur RAHMAN Department of Geography University of Peshawar Peshawar 25000 Pakistan Department of Geography Government College University Faisalabad Faisalabad 38000 Pakistan

Deforestation and other Land Use and Land Cover(LULC) changes, driven by variety of physical and anthropogenic factors, have altered the mountainous environment. Mountains around the world including northern and north western belts of Pakistan are highly sensitive to deforestation and other LULC changes, which have profound impacts on various sectors of bio-physical and socio-economic systems. Assessment of LULC changes has high significance for protection, conservation and monitoring mountainous environment. The present study is an attempt to assess the landscape changes with particular reference to forest cover depletion in Kurram Agency located in the north western mountain belt of Pakistan. For detailed comparative analysis the study area has been divided into three sections, which coincide with the present administrative divisions of the Agency, i.e., Upper,Lower and Central Kurram. Temporal span of this study covers four decades. In this study, land use map of 1970 and land sat satellite imageries of 1987, 2000 and 2014 were used as spatial data sets. The images were processed and classified into six LULC classes through geospatial packages and change detection maps were prepared for each division and time *** of the study reveal two trends in the four major LULC categories. Forest and rangeland have shrunk, on average, by 15% and 7.5% respectively while, bare soil and rocks outcrops have expanded by 89% and agriculture land by 7.2% in Kurram *** water bodies and snow cover have minor fluctuation in its land area. Major causes of shrinking greenery is attributed to high influx of Afghan refugees and high energy demand of growing population. However, with outflow of the refugees from Kurram agency the general trend in forest cover has reverted and deforestation rate has slowed down.

关键词： Pakistan Tribal areas Deforestation Land Use Land Cover Change Resource management Global changes

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

One-pot synthesis of various xanthene derivatives using ionic liquid1,3-disulfonic acid imidazolium hydrogen sulfate as an efficient and reusable catalyst under solvent-free conditions

引用

Chinese Chemical Letters 2014年第2期25卷 341-347页

作者： Farhad Shirini Asieh Yahyazadeh kamal Mohammadi Department of Chemistry College of Science.University of Guilan

In this study, 1,3-disulfonic acid imidazolium hydrogen sulfate （DSIMHS） is used as an efficient and reusable ionic liquid for the green, mild, and efficient synthesis of xanthenes under solvent-free conditions. Simple and easy work-up, low cost, green process, short reaction times and excellent yields of the products are the advantages of this procedure. Further, the catalyst can be recycled and reused at least for four times without a noticeably decrease in its catalytic activity.

关键词： Xanthene derivatives One-pot reaction 1,3-Disulfonic acid imidazolium hydrogensulfate Ionic liquid Solvent-free conditions

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

Investigating TiO_(2)-HA-PCL hybrid coating as an efficient corrosion resistant barrier of ZM21 Mg alloy

引用

Journal of Magnesium and Alloys 2021年第2期9卷 627-646页

作者： Navdeep Singh Uma Batra kamal Kumar Anil Mahapatro Department of Metallurgical and Materials Engineering Punjab Engineering CollegeChandigarh 160012India Department of Mechanical Engineering Punjab Engineering CollegeChandigarh 160012India Department of Biomedical Engineering Wichita State UniversityWichitaKS 67260United States

Surface modification for improving corrosion resistance of Mg alloys is highly demanded for degradable orthopedic and cardiovascular *** research reports the design and development of TiO_(2)–HA composite and novel TiO_(2)–HA–PCL hybrid coating belonging to the unique class of inorganic organic hybrid with striking features that are explored for the first time in the corrosion resistance of Mg ***–gel dip coating combined with non-solvent induced phase separation is used to create the hybrid ***_(2)–HA–PCL hybrid coating introduces strong hydrogen bonding between TiO_(2)–HA inorganic matrix and PCL organic layer in addition to the Vander wall electrostatic interaction of the later with the Mg substrate which in turn enhance adhesion strength to about 1.5 times of TiO_(2)–HA *** corrosion potentials for TiO_(2)–HA–PCL and TiO_(2)–HA were found to be-0.407 V and-1.017 V(vs Ag/Ag Cl),*** current densities of TiO_(2)–HA–PCL and TiO_(2)–HA were found to be 7.31×10^(-8)A/cm^(2)and 4.03×10^(-4)A/cm^(2)*** corrosion resistance of coatings was confirmed by immersion testing by weight loss,pH changes and H_(2)evolution measurements at interval of 7 days till 28 *** present TiO_(2)–HA–PCL coating in comparison to TiO_(2)–HA coating demonstrate nearly 6%less weight *** outcome of the present work was compared with the similar coatings in recent *** work done ingresses enhancing the corrosion resistance of Mg alloys,which fulfill the dreams of future degradable orthopedic and cardiovascular devices.

关键词： Corrosion resistance TiO_(2)-HA-PCL Contact angle Adhesion strength

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

Study of the Reaction of 5-Aryl-7-hydrazino-2-phenylpyra- zolo[1,5-c]pyrimidines with 1,3-Dicarbonyl Compounds

引用

Chinese Journal of Chemistry 2011年第11期29卷 2451-2460页

作者： Atta, kamal F. M. Chemistry Department Faculty of Science Alexandria University lbrahimia P. O. Box 426 Alexandria 21321 Egypt

A novel synthetic method for the preparation of 5-aryl-7-（3,5-dimethyl-lH-pyrazol-l-yl）-2-phenylpyra- zolo[1,5-c]-pyrimidines and 1-（5-aryl-2-phenylpyrazolo[1,5-c]pyrimidin-7-yl）-3-methyl-lH-pyrazol-5-ols is provided by condensative cyclization of 5-aryl-7-hydrazino-2-phenylpyrazolo[1,5-c]pyrimidines with 1,3-dicarbonyl compounds. The study of the more reactive position for electrophilic substitusion reactions on such ring system was also achieved.

关键词： cyclization electrophilic substitution pyrazolylpyrazolopyrimidine IR NMR mass spectrometry

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

An accurate retransmission timeout estimator for content-centric networking based on the Jacobson algorithm

引用

Digital Communications and Networks 2022年第6期8卷 1085-1093页

作者： Mortaza Nikzad kamal Jamshidi Ali Bohlooli Faiz Mohammad Faqiry Faculty of Computer Science Kabul Polytechnic UniversityKabulAfghanistan Faculty of Computer Engineering University of IsfahanIsfahanIran

Accurately estimating of Retransmission TimeOut (RTO) in Content-Centric Networking (CCN) is crucial for efficient rate control in end nodes and effective interface ranking in intermediate routers. Toward this end, the Jacobson algorithm, which is an Exponentially Weighted Moving Average (EWMA) on the Round Trip Time (RTT) of previous packets, is a promising scheme. Assigning the lower bound to RTO, determining how an EWMA rapidly adapts to changes, and setting the multiplier of variance RTT have the most impact on the accuracy of this estimator for which several evaluations have been performed to set them in Transmission Control Protocol/Internet Protocol (TCP/IP) networks. However, the performance of this estimator in CCN has not been explored yet, despite CCN having a significant architectural difference with TCP/IP networks. In this study, two new metrics for assessing the performance of RTO estimators in CCN are defined and the performance of the Jacobson algorithm in CCN is evaluated. This evaluation is performed by varying the minimum RTO, EWMA parameters, and multiplier of variance RTT against different content popularity distribution gains. The obtained results are used to reconsider the Jacobson algorithm for accurately estimating RTO in CCN. Comparing the performance of the reconsidered Jacobson estimator with the existing solutions shows that it can estimate RTO simply and more accurately without any additional information or computation overhead.

关键词： Content-centric networking Retransnissi on timeout Popularity distribution gain Jacobson RTO estimator

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

Evaluation of corrosion resistance, mechanical integrity loss and biocompatibility of PCL/HA/TiO_(2) hybrid coated biodegradable ZM21 Mg alloy

引用

Journal of Magnesium and Alloys 2022年第11期10卷 3179-3204页

A novel PCL/HA/TiO_(2)hybrid coating on ZM21 Mg alloy substrate has been investigated for corrosion resistance, biocompatibility and mechanical integrity loss in terms of bending, compressive and tensile strength in physiological media. The prepared hybrid coating was dip coated over ZM21 from HA/TiO_(2)and PCL solutions followed by creating a microporous PCL layer by utilizing Non-solvent Induced Phase Separation(NIPS) technique. The electrochemical measurement and in-vitro degradation study in SBF after 28 days showed that the PCL/HA/TiO_(2) hybrid coating reduced H2 evolution rate, weight loss, and corrosion rate by 64, 116 and 118 times respectively, as compared to uncoated ZM21 samples. The surface studies carried out using SEM-EDX, FTIR and XRD revealed formation of highly stable 3d flower-like HA crystals with Ca/P ratio of 1.60 in the PCL micropores. This dense apatite growth effectively protected the PCL/HA/TiO_(2)hybrid coated samples to maintain the good mechanical integrity even after 28 days of immersion as compared to HA/TiO_(2)composite coated, As-polished(A/P) and As-machined(A/M) samples. The failure analysis of samples under mechanical loading were performed using *** in-vitro cellular viability of L929 fibroblast cells on PCL/HA/TiO_(2)hybrid coating was found 50.47% higher with respect to control group,whereas bacterial viability was supressed by 57.15 and 62.35% against gram-positive Staphylococcus aureus and gram-negative Escherichia coli bacterial models. The comprehensive assessment indicates PCL/HA/TiO_(2)hybrid coating as a suitable candidate to delay early degradation and mechanical integrity loss of Mg-based alloys for devising biodegradable orthopaedic implant.

关键词： Magnesium alloy Surface modification Hybrid coating Mechanical integrity loss Degradation rate Biocompatibility

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

Finite element simulation of stress intensity factors in elastic-plastic crack growth

引用

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第8期7卷 1336-1342页

作者： ALSHOAIBI Abdulnaser M ARIFFIN Ahmad kamal Computational Mechanics Research Group Department of Mechanical and Materials Engineering Faculty of Engineering Universiiy Kebangsaan Malaysia Bangi 43600 Malaysia

A finite element program developed elastic-plastic crack propagation simulation using Fortran language. At each propagation step, the adaptive mesh is automatically refined based on a posteriori h-type refinement using norm stress error estimator. A rosette of quarter-point elements is then constructed around the crack tip to facilitate the prediction of crack growth based on the maximum normal stress criterion and to calculate stress intensity factors under plane stress and plane strain conditions. Crack was modelled to propagate through the inter-element in the mesh. Some examples are presented to show the results of the implementation.

关键词： Crack propagation Nodal displacement Stress intensity factor Adaptive mesh Finite element method (FEM)

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

Ensuring Secure Platooning of Constrained Intelligent and Connected Vehicles Against Byzantine Attacks:A Distributed MPC Framework

引用

Engineering 2024年第2期33卷 35-46页

作者： Henglai Wei Hui Zhang kamal AI-Haddad Yang Shi Department of Mechanical Engineering University of VictoriaVictoriaBC V8W 3P6Canada School of Transportation Science and Engineering Beihang UniversityBeijing 100191China École de Technologie Supérieure University of QuebecMontrealQC H3C 1K3Canada

This study investigates resilient platoon control for constrained intelligent and connected vehicles(ICVs)against F-local Byzantine *** introduce a resilient distributed model-predictive platooning control framework for such *** framework seamlessly integrates the predesigned optimal control with distributed model predictive control(DMPC)optimization and introduces a unique distributed attack detector to ensure the reliability of the transmitted information among ***,our strategy uses previously broadcasted information and a specialized convex set,termed the“resilience set”,to identify unreliable *** approach significantly eases graph robustness prerequisites,requiring only an(F+1)-robust graph,in contrast to the established mean sequence reduced algorithms,which require a minimum(2F+1)-robust ***,we introduce a verification algorithm to restore trust in vehicles under minor attacks,further reducing communication network *** analysis demonstrates the recursive feasibility of the DMPC ***,the proposed method achieves exceptional control performance by minimizing the discrepancies between the DMPC control inputs and predesigned platoon control inputs,while ensuring constraint compliance and *** results verify the effectiveness of our theoretical findings.

关键词： Model predictive control Resilient control Platoon control Intelligent and connected vehicle Byzantine attacks

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

Delineating Key Determinants of Domestic Fuelwood Consumption of Rural Households in Western Himalaya-Policy Implications

引用

Journal of Mountain Science 2014年第1期11卷 195-204页

作者： MUSHTAQ Tahir SOOD kamal Kishor PESHIN Rajinder Division of Agroforestry Sher-e-kashmir University of Agricultural Sciences and Technology Division of Agricultural Extension Education Sher-e-kashmir University of Agricultural Sciences and Technology

A study was carried out in district Samba of Western Himalayan province of Jammu and Kashmir of *** data were collected in an interview schedule in personal interview with 180 household *** association between the level of fuelwood consumption(low versus high consumption) and different factors,each individually,was investigated using chi-square test of association at 0.001 level of *** was found that out of 25 socio-economic,biophysical and alternate fuel factors,15 factors(each individually) significantly influenced the domestic fuelwood *** regression models of alternate fuel use,social,economic and biophysical factors were developed to identify key variables influencing fuelwood consumption levels within each respective category.A composite model was also developed to identify key factors when all variables in all the pre-said categories were considered ***,in contrast to expectation the model with alternate fuel use did not provide a good *** biophysical model also did not provide a good *** economic and composite models were the same with equal level of accuracy of *** implies that economic aspects,rather than the availability of alternate fuels,dominate fuelwood consumption levels of rural *** to increase the exposure of the head of household to outside world needs to formulated to reduce the domestic fuelwood consumption *** nearer to state forests are to be educated about efficient use of fuelwood and be encouraged to intensify use of Liquified Petroleum *** wider implications of study are:the availability of alternate fuels is not a necessary condition to decrease household level domestic fuelwood *** factors needs to be considered in designing strategies to reduce fuelwood *** employment opportunities would increase the opportunity cost of fuelwood collection and this would reduce its use.

关键词： Social Economic Household Alternate fuel Regression

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

Emerging monoelemental 2D materials(Xenes)for biosensor applications

引用

Nano Research 2023年第5期16卷 7030-7052页

作者： Xiaohan Duan Zhihao Liu Zhongjian Xie ayesha Khan Tareen Karim Khan Bin Zhang Han Zhang Key Laboratory of Optoelectronic Devices Systems of Ministry of Education and Guangdong ProvinceCollege of Physics and Optoelectronic Engineering and Institute of Translational MedicineFirst Affiliated Hospital(Shenzhen Second People’s Hospital)Health Science CenterShenzhen UniversityShenzhen 518060China Institute of Pediatrics Shenzhen Children’s HospitalShenzhen 518038China School of Mechanical Engineering Dongguan University of TechnologyDongguan 523808China School of Electrical Engineering&Intelligentization Dongguan University of TechnologyDongguan 523808China

Currently,numerous monoelemental two-dimensional(2D)materials,called Xenes,have been discovered,including graphyne(GD),silicene,germanene,arsenene,*** structures,fabrication methods,as well as properties have been extensively *** on their single-element composition,high optical response capability,excellent electrical-optical properties,large specific surface area(SSA)and easy modification,Xenes have been widely used in photoelectric applications(detection,modulation,light processing)and biomedicine(biological sensing,drug loading,bioimaging,etc.).Especially in the field of biomedicine,Xenes are expected to induce a great *** this review,we introduce the structural characteristics,synthesis and modification methods of several common Xenes *** general properties including optical,electronic,physical and chemical properties of Xenes are *** diverse utilization as biosensors for nucleic acid sequencing,bioactive detection,cancer diagnosis,*** also explicitly ***,the challenges and future perspectives of Xenes in biosensor are discussed.

关键词： Xenes fabrication method general properties biosignal detection biosensors

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

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：