检索结果-南通市图书馆

Updating of the hierarchical rock mass rating(HRMR) system and a new subsystem developed for weathered granite formations

引用

International j.urnal of Mining Science and Technology 2014年第6期24卷 769-775页

作者： miranda Tiago e Sousa L.Ribeiro Tinoco j.aquim ISISE University of Minho Guimar?es 4800-058 Portugal State Key Laboratory of Geomechanics and Deep Underground Engineering China University of Mining & Technology University of Porto Porto 4200 Portugal

The RMR system is still very much applied in rock mechanics engineering context. It is based on the evaluation of six weights to obtain a final rating. To obtain the final rating a considerable amount of information is needed concerning the rock mass which can be difficult to obtain in some proj.cts or proj.ct stages at least with accuracy. In 2007 an alternative classification scheme based on the RMR, the Hierarchical Rock Mass Rating(HRMR) was presented. The main feature of this system was the adaptation to the level of knowledge existent about the rock mass to obtain the classification of the rock mass since it followed a decision tree approach. However, the HRMR was only valid for hard rock granites with low fracturing degrees. In this work, the database was enlarged with approximately 40% more cases considering other types of granite rock masses including weathered granites and based on this increased database the system was updated. Granite formations existent in the north of Portugal including Porto city are predominantly granites. Some years ago a light rail infrastructure was built in the city of Porto and surrounding municipalities which involved considerable challenges due to the high heterogeneity levels of the granite formations and the difficulties involved in their geomechanical characterization. In this work it is intended to provide also a contribution to improve the characterization of these formations with special emphasis to the weathered horizons. A specific subsystem applicable to the weathered formations was developed. The results of the validation of these systems are presented and show acceptable performances in identifying the correct class using less information than with the RMR system.

关键词： Rock mass classification system Decision tree Weathered granite formations

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

Bivariate Analysis of Pollutants Monthly Maxima in Mexico City Using Extreme Value Distributions and Copula

引用

j.urnal of Environmental Protection 2024年第7期15卷 796-826页

作者： j.an A. Vazquez-Morales Eliane R. Rodrigues Hortensia j. reyes-Cervantes Facultad de Ciencias Fsico-Matemticas Benemrita Universidad Autnoma de Puebla Puebla Mexico Instituto de Matemticas Universidad Nacional Autnoma de Mxico Mexico City Mexico

In the present work, we are interested in studying the j.int distributions of pairs of the monthly maxima of the pollutants used by the environmental authorities in Mexico City to classify the air quality in the metropolitan area. In order to obtain the j.int distributions a copula will be considered. Since we are analyzing the monthly maxima, the extreme value distributions of Weibull and Fréchet are taken into account. Using these two distributions as marginal distributions in the copula a Bayesian inference was made in order to estimate the parameters of both distributions and also the association parameters appearing in the copula model. The pollutants taken into account are ozone, nitrogen dioxide, sulphur dioxide, carbon monoxide, and particulate matter with diameters smaller than 10 and 2.5 microns obtained from the Mexico City monitoring network. The estimation was performed by taking samples of the parameters generated through a Markov chain Monte Carlo algorithm implemented using the software OpenBugs. Once the algorithm is implemented it is applied to the pairs of pollutants where one of the coordinates of the pair is ozone and the other varies on the set of the remaining pollutants. Depending on the pollutant and the region where they were collected, different results were obtained. Hence, in some cases we have that the best model is that where we have a Fréchet distribution as the marginal distribution for the measurements of both pollutants and in others the most suitable model is the one assuming a Fréchet for ozone and a Weibull for the other pollutant. Results show that, in the present case, the estimated association parameter is a good representation to the correlation parameters between the pair of pollutants analyzed. Additionally, it is a straightforward task to obtain these correlation parameters from the corresponding association parameters.

关键词： Copula Extreme Value Distribution Bayesian Inference Air Pollution Mexico City

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

The “behind-the-knee” test for menstrual tampon irritation

引用

Open j.urnal of Obstetrics and Gynecology 2012年第1期2卷 34-38页

作者： miranda A. Farage Kenneth W. Miller William j. Ledger Department of Obstetrics and Gynecology The New York-Presbyterian Hospital Weill Medical College Cornell University New York USA Feminine Clinical Sciences The Procter & Gamble Company Cincinnati USA

Colposcopic inspection of the vagina is a routine component of the safety assessment of intravaginal products. However, colposcopic findings occur frequently in healthy women, raising questions about their relevance to intravaginal product safety. Practical disadvantages limit the utility of colposcopy for evaluating menstrual tampons, among them the presence of background microtrauma, the inability to assess effects during menstruation, and, importantly, the question of whether post-hoc assessments are sufficiently sensitive to detect small inflammatory changes. The Behind-the-knee (BTK) test is an alternative for evaluating inflammatory and tissue dryness effects of physical articles by their repeated application to the popliteal fossa under an elastic bandage. It enables concurrent parallel comparisons of experimental and control articles over time and substantially increases the sensitivity of detecting small changes in tissue inflammation. With this protocol, uncompressed experimental and control tampons yielded comparable relative and absolute erythema scores (after overnight recovery) as did colposcopic assessment of the lower genital tract 3 to 48 hours after menstrual use. Scoring erythema in the BTK test immediately after product removal increased the level of visually discernible inflammation 6-fold. In a study of commercial menstrual pads, subclinical inflammation visualized with cross-polarized light correlated with the frequency of subj.ctive reports of discomfort during the test and discriminated the relative tolerability of the two products determined by market surveillance, providing added confidence in the predictive value of the test. We believe the BTK test to be a valuable alternative to colposcopy for assessing inflammation and dryness associated with menstrual tampons.

关键词： Colposcopy Behind-the-Knee Menstrual Tampons

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

Effect of Milling Time on the Microstructure and Tensile Properties of Ultrafine Grained Ni–SiC Composites at Room Temperature

引用

j.urnal of Materials Science & Technology 2015年第9期31卷 923-929页

作者： Hefei Huang Chao Yang Massey de los reyes Yongfeng Zhou Long Yan Xingtai Zhou Shanghai Institute of Applied Physics Chinese Academy of Sciences Institute of Materials Engineering Australian Nuclear Science and Technology Organisation

Bulk metallic nickel-silicon carbide nano-particle （Ni-SiCNp） composites, with milling time ranged from 8 to 48 h, were prepared in a planetary ball mill and sintered using a spark plasma sintering （SPS） furnace. The microstructure of the Ni-SiCnp composites was characterized by transmission electron microscopy （TEM） and their mechanical properties were investigated by tensile measurements. The TEM results showed well-dispersed SiCNp particles, either within the matrix, between twins or along grain boundaries （GB）, as well as the presence of stacking faults and twin structures, characteristics of materials with low stacking fault energy. Dislocation lines were also observed to interact with the SiCNp which were plastically nondeformable. A synergistic relationship existed between Hall-Perch strength- ening and dispersion strengthening mechanisms, which was shown to greatly influence the mechanical properties of the Ni-SiCNp composites. Both the maximum yield and tensile strengths were found in the Ni-SiCNp composite with a milling time of 48 h, whereas the increased rate of strengths drastically decreased in material milled above 8 h due to the significant SiCNp agglomeration. The ball milling process resulted in the formation of nano-scale, ultra-fine grained （UFG） Ni-SiCNp composites when the milling time was extended for longer periods, greatly strengthening these materials. The sharp decrease in elongation percentages, however, should be comprehensively considered before irrevers- ible inelastic deformation.

关键词： Ni-SiCNp compositeMechanical alloyingSpark plasma sinteringTransmission electron microscopyTensile testUltra-fine grained (UFG)

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

Application of a Pulsed Electric Field to Modify the Free Energy of the Active Site of an Azoreductase

引用

j.urnal of Applied Mathematics and Physics 2024年第1期12卷 249-255页

作者： j.sus Magyber de j.sus miranda Pedro Guillermo reyes-Romero j.rge Mulia-Rodríguez Daniel Osorio-González Molecular Biophysics Laboratory Faculty of Sciences Autonomous University of State of Mexico Toluca Mexico Advanced Physics Laboratory Faculty of Sciences Autonomous University of State of Mexico Toluca Mexico

The Gibbs free energy is strongly related to the stability and catalytic function of an enzyme through the energetic changes that occur in the chemical reactions the enzyme catalyzes. In this in silico study, a pulsed electric field was applied to an azoreductase, and its effect on the Gibbs free energy of molecular docking with two dyes was measured. We propose that certain stimuli from a pulsed electric field favor the structural stability of the enzyme by promoting an arrangement in the active site, potentially leading to an enhancement of enzymatic activity overall.

关键词： Pulsed Electric Field Molecular Dynamics Docking Azoreductase

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

Numerical Integration of Forced and Damped Oscillators through a New Multistep Method

引用

j.urnal of Applied Mathematics and Physics 2019年第10期7卷 2440-2458页

作者： M. Cortés-Molina F. García-Alonso j. A. reyes Department of Applied Mathematics Escuela Politécnica Superior University of Alicante Alicante Spain

Forced and damped oscillators appear in the mathematical modelling of many problems in pure and applied sciences such as physics, engineering and celestial mechanics among others. Although the accuracy of the T-functions series method is high, the calculus of their coefficients needs specific recurrences in each case. To avoid this inconvenience, the T-functions series method is transformed into a multistep method whose coefficients are calculated using recurrence procedures. These methods are convergent and have the same properties to the T-functions series method. Numerical examples already used by other authors are presented, such as a stiff problem, a Duffing oscillator and an equatorial satellite problem when the perturbation comes from zonal harmonics j..

关键词： Numerical Solutions of ODE’s Perturbed and Damped Oscillators Initial Value Problems (IVP) Multistep Methods

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

以田鼠作为动物模型来研究社会行为的进化:基因、脑与行为(英文)

引用

动物学报 2004年第4期50卷 479-489页

作者： miranda M. LIM Elizabeth A.D. HAMMOCK Larry j. YOUNG Center for Behavioral Neuroscience Department of Psychiatry and Behavioral Sciences Emory University Atlanta GA 30322 USACenter for Behavioral Neuroscience Department of Psychiatry and Behavioral Sciences Emory University Atlanta GA 30322 USACenter for Behavioral Neuroscience Department of Psychiatry and Behavioral Sciences Emory University Atlanta GA 30322 USA

田鼠属的一些近缘种间具有独特的社会行为多态性。例如Microtusochrogaster和M .pinetorum为一夫一妻制 ,而M .montanus和M .pennsylvanicus则为独居和一夫多妻制。无论是在野外还是人工饲养的条件下 ,单配制的田鼠其雌、雄成年个体一... 详细信息

田鼠属的一些近缘种间具有独特的社会行为多态性。例如Microtusochrogaster和M .pinetorum为一夫一妻制 ,而M .montanus和M .pennsylvanicus则为独居和一夫多妻制。无论是在野外还是人工饲养的条件下 ,单配制的田鼠其雌、雄成年个体一经交配即在两者之间形成长期的配偶关系并且双亲共同哺育后代。已证明神经多肽加压素 (Vasopressin)参与了田鼠单配制行为的神经调控。本篇综述了过去以及近期关于加压素调控田鼠配偶关系形成的研究结果和进展。首先 ,阐述了加压素V1a受体 (V1aR)在脑分布的种间差异 ,并以此来鉴别特定脑区在配偶关系形成中的功能 ;其次 ,探讨了运用V1aR拮抗物的药理学方法来决定究竟哪些脑区参与配偶关系的形成 ,还描述了田鼠种间V1aR基因结构和功能的不同 ,以及这些不同对V1aR在大脑的分布和行为调控潜在的作用机制 ;最后 ,讨论了最新的研究结果 ,即对一夫多妻制田鼠进行脑V1aR基因的改造 ,从而使之表现出一夫一妻制田鼠的行为。总之。

关键词：田鼠动物模型社会行为进化基因脑

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

Non-destructive microstructural analysis by electrical conductivity:Comparison with hardness measurements in different materials

引用

j.urnal of Materials Science & Technology 2019年第3期35卷 360-368页

作者： Gon?alo L.Sorger j.P.Oliveira Patrick L.Inácio Norbert Enzinger Pedro Vila? R.M.miranda Telmo G.Santos Department of Engineering Design and Production School of Engineering Aalto University Department of Materials Science and Engineering The Ohio State University UNIDEMI Departamento de Engenharia Mecanica e Industrial Faculdade de Ciências e Tecnologia Universidade Nova de Lisboa IMAT-Institute of Materials Science Joining and FormingTU Graz

The use of non-destructive evaluation(NDE) techniques for assessing microstructural changes in processed materials is of particular importance as it can be used to assess, qualitatively, the integrity of any material/structure. Among the several NDE techniques available, electrical conductivity measurements using eddy currents attract great attention owing to its simplicity and reliability. In this work, the electrical conductivity profiles of friction stir processed Ti6Al4 V, Cu, Pb, S355 steel and gas tungsten arc welded AISI 304 stainless steel were determined through eddy currents and four-point probe. In parallel, hardness measurements were also performed. The profiles matched well with the optical macrographs of the materials: while entering in the processed region a variation in both profiles was always observed. One particular advantage of electrical conductivity profiles over hardness was evident: it provides a better resolution of the microstructural alterations in the processed materials. Moreover, when thermomechanical processing induces microstructural changes that modify the magnetic properties of a material,eddy currents testing can be used to qualitatively determine the phase fraction in a given region of the material. A qualitative relation between electrical conductivity measurements and hardness is observed.

关键词： Non-destructive evaluation techniques Electrical conductivity Hardness Friction stir processing Gas tungsten arc welding

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

Improved Analytical Methods for Determination of Residues of Nitrapyrin and 6-Chloropicolinic Acid in Different Crop Matrices by Liquid Chromatography-Tandem Mass Spectrometry

引用

j.urnal of Agricultural Chemistry and Environment 2024年第3期13卷 263-281页

作者： Fabiola G. Zuno-Floriano Riza L. reyes-Punongbayan Matt j. Hengel Department of Environmental Toxicology University of California Davis California USA

Novel analytical methods were developed for the determination of nitrapyrin and 6-chloropicolinic acid (6-CPA) residues in agricultural products. Nitrapyrin was extracted with hexane: toluene (1:1, v/v) and 6-CPA with 0.1 N sodium hydroxide (NaOH). For nitrapyrin, samples were cleaned with silica solid phase extraction (SPE) and for 6-CPA with C18 or carbon SPE. Analysis was performed by liquid chromatography-tandem mass spectroscopy (LC-MS/MS) with external calibration (0.010 to 0.0010 µg∙mL−1 for nitrapyrin and 0.0050 to 0.00025 µg∙mL−1 for 6-CPA). Recoveries for nitrapyrin and 6-CPA were 68% - 102% and 66% - 90%, respectively. Nitrapyrin was detected in celery and onion (−1) and 6-CPA in onion, mustard greens and lettuce (−1). Lower level method validation (LLMV) for nitrapyrin and 6-CPA was 0.020 µg∙g−1 and 0.050 µg∙g−1, respectively. The methods presented in this study are robust and were utilized for the registration of nitrapyrin on agricultural commodities in the United States.

关键词： Herbicide Agricultural Products External Calibration LC-MS/MS Registration

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

Blue-Red Tuning Emission of ZnO: Europium Quantum Dots with Different Excitation Wavelengths

引用

Open j.urnal of Applied Sciences 2018年第10期8卷 441-445页

作者： Primitivo Ortiz Maldonado Ana K. Chavez-Alvarado Francisco j. Rodríguez Gutierrez j.an reyes miranda Dulce Y. Medina Velazquez Miguel A. Barron Elizabeth Garfias García Universidad Autónoma Intercultural de Sinaloa El Fuerte México División de Ciencias Básicas e Ingeniería Universidad Autónoma Metropolitana Reynosa Tamaulipas México

Optoelectronic applications require the development of new fluorescent and efficient luminescent materials, free of toxicity, low in cost, and easy to produce. In this way the synthesis of zinc-oxide (ZnO) quantum dots (QDs) has recently received special attention due to their good optical, electrical and chemical properties with low production costs and blue light emission. In this work ZnO QDs were successfully doped with europium in order to obtain a tunable emission luminescence from blue emission of ZnO to red emission of europium as a function of wavelength excitation. Results show an efficient blue to red tuning when the excitation wavelength was changed from 317 nm to 395 nm, respectively. This opens the possibility of having new optical devices to produce different color emission using the same material.

关键词： Chromaticity Diagram Emission Spectra Europium Luminescence Red-Blue Tuning ZnO Quantum Dots White Light

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：