检索结果-南通市图书馆

Boron-modified perhydropolysilazane towards facile synthesis of amorphous SiBN ceramic with excellent thermal stability

引用

Journal of Advanced Ceramics 2022年第7期11卷 1104-1116页

作者： Ying ZHAN Wei LI Tianshu JIANG Claudia FASEL emmanuel iii ricohermoso Jan BERNAUER Zhaoju YU Zhenghao WU Florian MÜLLER-PLATHE Leopoldo MOLINA-LUNA Ralf GROTTENMÜLLER Ralf RIEDEL Department of Materials and Earth Sciences Technical University of DarmstadtD-64287 DarmstadtGermany College of Materials Key Laboratory of High Performance Ceramic Fibers(Xiamen University)Ministry of EducationXiamen 361005China Eduard-Zintl-Institut für Anorganische und Physikalische Chemie Technical University of DarmstadtD-64287 DarmstadtGermany Merck KGaA Performance MaterialsD-64293DarmstadtGermany

SiBN ceramics are widely considered to be the most promising material for microwavetransparent applications in harsh environments owing to its excellent thermal stability and low dielectric *** work focuses on the synthesis and ceramization of single-source precursors for the preparation of SiBN ceramics as well as the investigation of the corresponding microstructural evolution at high temperatures including molecular dynamic ***-and chlorine-free perhydropolysilazanes were reacted with borane dimethyl sulfide complex at different molar ratios to synthesize single-source precursors,which were subsequently pyrolyzed and annealed under N2 atmosphere(without ammonolysis)to prepare SiBN ceramics at 1100,1200,and 1300℃with high ceramic yield in contrast to previously widely-used ammonolysis synthesis *** obtained amorphous SiBN ceramics were shown to have remarkably improved thermal stability and oxidation resistance compared to amorphous silicon ***,the experimental results have been combined with molecular dynamics simulation to further study the amorphous structure of SiBN and the atomic-scale diffusion behavior of Si,B,and N at 1300℃.Incorporation of boron into the Si–N network is found to suppress the crystallization of the formed amorphous silicon nitride and hence improves its thermal stability in N2 atmosphere.

关键词： polymer-derived ceramics(PDCs) SiBN crystallization molecular dynamics oxidation resistanc

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

Hard and tough novel high-pressure γ-Si_(3)N_(4)/Hf_(3)N_(4) ceramic nanocomposites

引用

Journal of Advanced Ceramics 2023年第7期12卷 1418-1429页

作者： Wei Li Zhaoju Yu Leonore Wiehl Tianshu Jiang Ying Zhan emmanuel iii ricohermoso Martin Etter Emanuel Ionescu Qingbo Wen Christian Lathe Robert Farla Dharma Teppala Teja Sebastian Bruns Marc Widenmeyer Anke Weidenkaff Leopoldo Molina-Luna Ralf Riedel Shrikant Bhat Department of Materials and Earth Sciences Technical University of DarmstadtDarmstadt 64283Germany Key Laboratory of High Performance Ceramic Fibers(Xiamen University) Ministry of EducationCollege of MaterialsXiamen UniversityXiamen 361005China Deutsches Elektronen-Synchrotron DESY Hamburg 22607Germany Fraunhofer IWKS Department Digitalization of ResourcesAlzenau 63755Germany State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China Deutsches GeoForschungsZentrum Potsdam Potsdam 14473Germany

Cubic silicon nitride(-Si_(3)N_(4))is superhard and one of the hardest materials after diamond and cubic boron nitride(cBN),but has higher thermal stability in an oxidizing environment than diamond,making it a competitive candidate for technological applications in harsh conditions(e.g.,drill head and abrasives).Here,we report the high-pressure synthesis and characterization of the structural and mechanical properties of a γ-Si_(3)N_(4)/Hf_(3)N_(4) ceramic nanocomposite derived from single-phase amorphous silicon(Si)-hafnium(Hf)-nitrogen(N)*** synthesis of the-Si_(3)N_(4)/Hf_(3)N_(4) nanocomposite is performed at~20 GPa and ca.1500 ℃ in a large volume multi anvil *** structural evolution of the amorphous precursor and its crystallization to-Si_(3)N_(4)/Hf_(3)N_(4) nanocomposites under high pressures is assessed by the in situ synchrotron energy-dispersive X-ray diffraction(ED-XRD)measurements at~19.5 GPa in the temperature range of ca.1000-1900℃.The fracture toughness(K_(IC))of the two-phase nanocomposite amounts~6/6.9 MPa·m^(1/2) and is about 2 times that of single-phaseγ-Si_(3)N_(4),while its hardness of ca.30 GPa remains *** work provides a reliable and feasible route for the synthesis of advanced hard and tough-Si_(3)N_(4)-based nanocomposites with excellent thermal stabililty.

关键词： cubic silicon nitride(γ-Si_(3)N_(4))/Hf_(3)N_(4) ceramic nanocomposites in situ synchrotron radiation mechanical properties thermal stability

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

Chemotherapy and its evolving role in the management of advanced prostate cancer

引用

Asian Journal of Andrology 2014年第3期16卷 334-340页

作者： Michael T Schweizer emmanuel S Antonarakis Prostate Cancer Research Program Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins Baltimore Maryland USA

Advanced prostate cancer has been recognized as being responsive to androgen deprivation since the 1940s when Charles Huggins first described the role of surgical castration in managing these patients. However, androgen deprivation only results in transient disease control for the vast majority of men, with those progressing in spite of castrate testosterone levels labeled as having castrate-resistant prostate cancer （CRPC）. Until 2004, the therapeutic arena for these patients had remained stagnant, with no agent having shown a survival gain in the CRPC setting. Two landmark publications changed the prostate cancer treatment landscape by providing ＇level-1 evidence＇ that docetaxel-based chemotherapy led to prolongation in overall survival （OS）. This was followed by the approval of cabazitaxel in 2010 on the basis of Phase iii data demonstrating its efficacy in patients pretreated with docetaxel. More recently, a number of next-generation androgen-directed agents （e.g. abiraterone and enzalutamide） have also been shown to lead to a survival benefit in men with CRPC. With so many new treatment options available, a number of questions remain. These include： how to best sequence chemotherapy with these newer hormonal agents, the clinical implication of cross-resistance between taxanes and androgen-directed agents and which subsets of patients may benefit most from early use of chemotherapy. This review will provide an overview of the evolving role of chemotherapy in the management of advanced prostate cancer in the current era.

关键词： cabazitaxel chemotherapy cyclophosphamide docetaxel mitoxantrone prostate cancer taxanes

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

Bolstering integrity in environmental data science and machine learning requires understanding socioecological inequity

引用

Frontiers of Environmental Science & Engineering 2024年第5期18卷 171-179页

作者： Joe F.Bozeman iii School of Civil and Environmental Engineering Georgia Institute of TechnologyAtlantaGA30332USA School of Public Policy Georgia Institute of TechnologyAtlantaGA30332USA

Socioecological inequity in environmental data science—such as inequities deriving from data-driven approaches and machine learning(ML)—are current issues subject to debate and *** is growing consensus around embedding equity throughout all research and design domains—from inception to administration,while also addressing procedural,distributive,and recognitional ***,practically doing so may seem onerous or daunting to *** current perspective helps to alleviate these types of concerns by providing substantiation for the connection between environmental data science and socioecological inequity,using the Systemic Equity Framework,and provides the foundation for a paradigmatic shift toward normalizing the use of equity-centered approaches in environmental data science and ML *** the integrity of environmental data science and ML is just beginning from an equity-centered tool development and rigorous application *** this end,this perspective also provides relevant future directions and challenges by overviewing some meaningful tools and strategies—such as applying the Wells-Du Bois Protocol,employing fairness metrics,and systematically addressing irreproducibility;emerging needs and proposals—such as addressing data-proxy bias and supporting convergence research;and establishes a ten-step path ***,the work that environmental scientists and engineers do ultimately affect the well-being of us all.

关键词： Equity Bias Machine Learning Data Science Justice Systemic Equity

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

Testosterone therapy in men with prostate cancer： literature review, clinical experience, and recommendations

引用

Asian Journal of Andrology 2015年第2期17卷 206-211,I0007页

作者： Abraham Morgentaler William P Conners iii Men's Health Boston 200 Boylston St Suite A309 Chestnut Hill MA 02467 USA.

For several decades any diagnosis of prostate cancer （PCa） has been considered an absolute contraindication to the use of testosterone （T） therapy in men. Yet this prohibition against T therapy has undergone recent re-examination with refinement of our understanding of the biology of androgens and PCa, and increased appreciation of the benefits of T therapy. A reassuringly low rate of negative outcomes has been reported with T therapy after radical prostatectomy （RP）, radiation treatments, and in men on active surveillance. Although the number of these published reports are few and the total number of treated men is low, these experiences do provide a basis for consideration of T therapy in selected men with PCa. For clinicians considering offering this treatment, we recommend first selecting patients with low grade cancers and undetectable prostate-specific antigen following RP. Further research is required to define the safety of T therapy in men with PCa. However, many patients symptomatic from T deficiency are willing to accept the potential risk of PCa progression or recurrence in return for the opportunity to live a fuller and happier life with T therapy.

关键词： androgen deprivation androgens hypogonadism prostate cancer prostate-specific antigen testosterone testosterone therapy

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

Electrochemical and spectroelectrochemical characterization of different mesoporous TiO2 film electrodes for the immobilization of Cytochrome c

引用

Frontiers of Materials Science 2018年第1期12卷 64-73页

作者： Stavros KATSIAOUNIS Christina TIFLIDIS Christina TSEKOURA emmanuel TOPOGLIDIS Department of Materials Science University of Patras Rion 26504 Greece

In this work three different mesoporous TiO2 film electrodes were prepared and used for the immobilization of Cytochrome c （Cyt-c）. Films prepared via a standard sol-gel route （SG-films） were compared with commercially available benchmark nanotitania materials, namely P25 Degussa （P25-films） and Dyesol nanopaste （Dyesol films）. Their properties, film deposition characteristics and their abilities to adsorb protein molecules in a stable and functional way were examined. We investigated whether it is possible, rather than preparing TiO2 films using multistep, lengthy and not always reproducible sol-gel procedures, to use commercially available nanotitania materials and produce reproducible films faster that exhibit all the properties that make TiO2 films ideal for protein immobilization. Although these materials are formulated primarily for dye-sensitized solar cell applications, in this study we found out that protein immobilization is facile and remarkably stable on all of them. We also investigated their electrochemical properties by using cyclic voltammetry and spectroelectrochemistry and found out that not only direct reduction of Fe（iii）-heme to Fe（II）-heme of immobilized Cyt-c was possible on all flms but that the adsorbed protein remained electroactive.

关键词： TiO2 films spectroelectrochemistry cyclic voltammetry Cytochrome c

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

Consistent constitutive modeling of metallic target penetration using empirical, analytical, and numerical penetration models

引用

Defence Technology（防务技术） 2016年第2期12卷 201-213页

作者： John(Jack) P.RIEGEL iii David DAVISON R3 Technology Inc. 7324 Fountain Spring Ct. Shock Transients Inc.

Historically, there has been little correlation between the material properties used in(1) empirical formulae,(2) analytical formulations, and(3) numerical models. The various regressions and models may each provide excellent agreement for the depth of penetration into semi-infinite targets. But the input parameters for the empirically based procedures may have little in common with either the analytical model or the numerical model. This paper builds on previous work by Riegel and Anderson(2014) to show how the Effective Flow Stress(EFS) strength model, based on empirical data, can be used as the average flow stress in the analytical Walker–Anderson Penetration model(WAPEN)(Anderson and Walker,1991) and how the same value may be utilized as an effective von Mises yield strength in numerical hydrocode simulations to predict the depth of penetration for eroding projectiles at impact velocities in the mechanical response regime of the materials. The method has the benefit of allowing the three techniques(empirical, analytical, and numerical) to work in tandem. The empirical method can be used for many shot line calculations, but more advanced analytical or numerical models can be employed when necessary to address specific geometries such as edge effects or layering that are not treated by the simpler methods. Developing complete constitutive relationships for a material can be costly. If the only concern is depth of penetration, such a level of detail may not be required. The effective flow stress can be determined from a small set of depth of penetration experiments in many cases, especially for long penetrators such as the L/D = 10 ones considered here, making it a very practical approach. In the process of performing this effort, the authors considered numerical simulations by other researchers based on the same set of experimental data that the authors used for their empirical and analytical assessment. The goals were to establish a baseline with a full constitut

关键词：本构模型渗透模型数值模型金属靶材料性质流动应力程序模拟数值计算

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

The effects of cues from kingsnakes on the reproductive effort of house mice

引用

Current Zoology 2013年第1期59卷 135-141页

作者： W. Wallace STARKE iii Michael H. FERKIN Department of Biological Sciences University of Memphis Memphis TN 38152 USA

It is not clear if rodents express inducible defenses in response to reptilian predators such as snakes. We tested the hypothesis that adult house mice Mus musculus decrease aspects of their reproductive effort upon 1 hour of exposure every 48 hours for a 25-day period to the fecal material and shed skins of a euryphagous ophidian predator, the kingsnake Lampropeltis getula, that had been fed mice. We found no significant differences in the total number of offspring born, the number of pups per litter, and the mean weight of pups in litters born to male and female mice that were exposed to predator cues and those mice that were not exposed to such cues. The lack of an inducible response may be associated with the low cost of an effective defense, or the lack of an effective defense against a generalist snake predator [Current Zoology 59 （1）： 135-141, 2013].

关键词： Inducible defenses Breeding suppression Lampropeltis getula Mus musculus Predator-prey interactions

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

TREMble Before TREM2:The Mighty Microglial Receptor Conferring Neuroprotective Properties in TDP-43 Mediated Neurodegeneration

引用

Neuroscience Bulletin 2023年第1期39卷 163-166页

作者： William A.Mills iii Ukpong B.Eyo Brain Immunology and Glia Center University of VirginiaCharlottesvilleVA22903USA Department of Neuroscience University of VirginiaCharlottesvilleVA22903USA Robert M.Berne Cardiovascular Research Center University of VirginiaCharlottesvilleVA22903USA

Microglia were long hailed as solely infammatory cells,and though they are responsible for the brain's immuneresponse,they perform a variety of neuroprotective func-tions including the clearance of cellular and toxic debris^([1]).One toxic molecule known to be cleared by microglia isthe protein aggregate found in Alzheimer's Disease(AD),amyloid-B.

关键词： protective degeneration Alzheimer

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

Quantifying the early snowmelt event of 2015 in the Cascade Mountains,USA by developing and validating MODIS-based snowmelt timing maps

引用

Frontiers of Earth Science 2018年第4期12卷 693-710页

作者： Donal O'LEARY iii Dorothy HALL Michael MEDLER Aquila FLOWER University of Maryland Department of Geographical SciencesCollege ParkMD 20740USA Westem Washington University Department of Environmental StudiesBellinghamWA 98225USA National Aeronautics and Space Administration Goddard Space Flight CenterGreenbeltMD 20771USA Earth System Science Interdisciplinary Center University of MarylandCollege ParkMD 20740USA

Spring snowmelt serves as the major hydrological contribution to many watersheds of the US West. Since the 1970s the conterminous western USA has seen an earlier arrival of spring snowmelt. The extremely low snowpack and early melt of 2015 in the Cascade Mountains may be a harbinger of winters to come, underscoring the interest in advancements in spring snowmelt monitoring. Target-of-opportunity and point measurements of snowmelt using meteorological stations or stream gauges are common sources of these data, however, there have been few attempts to identify snowmelt timing using remote sensing. In this study, we describe the creation of snowmelt timing maps (STMs) which identify the day of year that each pixel of a remotely sensed image transitions from “snow-covered” to “no snow” during the spring melt season, controlling for cloud coverage and ephemeral spring snow storms. Derived from the 500 m MODerate-resolution Imaging Spectroradiometer (MODIS) standard snow map, MOD10A2, this new dataset provides annual maps of snowmelt timing, with corresponding maps of cloud interference and interannual variability in snow coverage from 2001-2015. We first show that the STMs agree strongly with in-situ snow telemetry (SNOTEL) meteorological station measurements in terms of snowmelt timing. We then use the STMs to investigate the early snowmelt event of 2015 in the Cascade Mountains, USA, highlighting the protected areas of Mt. Rainier, Crater Lake, and Lassen Volcanic National Parks. In 2015 the Cascade Mountains experienced snowmelt 41 days earlier than the 2001-2015 average, with 25% of its land area melting>65 days earlier than average. The upper elevations of the Cascade Mountains experienced the greatest snowmelt anomaly. Our results are relevant to land managers and biologists as they plan adaptation strategies for mitigating the effects of climate change throughout temperate mountains.

关键词： Cascade Mountains snowmelt spring phenology MODIS remote sensing

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：