检索结果-南通市图书馆

Electromagnetic wave absorbing ceramics composites made of polymer-derived SiC with BN@CNTs pyrolyzed higher than 1200℃

引用

Journal of Materials Science & Technology 2023年第36期167卷 213-227页

作者： Bin Ren Yumeng deng Yujun Jia Xiaopeng Wu Guanghui Feng qian Wang Hejun Li State Key Laboratory of Solidification Processing Shaanxi Key Laboratory of Fiber Reinforced Light Composite MaterialsNorthwestern Polytechnical UniversityXi’an 710072China Henan Key Laboratory of High Performance Carbon Fiber Reinforced Composites Institute of Carbon Matrix CompositesHenan Academy of SciencesZhengzhou 450046China

Polymer-derived ceramics(PDCs)pyrolyzed at high temperatures are promising electromagnetic wave(EMW)absorption materials for aerodynamically heated parts of aircraft under harsh ***-ertheless,high-temperature pyrolysis results in a significant increase of electrical and dielectric proper-ties of the ceramics,causing extensive reflection of *** address this challenge,boron nitride-coated carbon nanotubes(BN@CNTs)were fabricated and introduced into polymer-derived SiC(PDC-SiC)by py-rolyzing its precursor higher than 1200℃to form SiC-BN@CNT ceramic *** fabricated com-posites with 3 wt.%BN@CNTs pyrolyzed at 1200℃have an effective absorption bandwidth(EAB)of 4.2 GHz(8.2-12.4 GHz)at a thickness of 3.4 mm and the minimum reflection loss(RL min)of-57.20 *** ultra-broad EAB of 12.62 GHz(5.38-18 GHz)is obtained by simulation through periodic structure *** RL of the metamaterials was also measured using an arch testing method at a frequency range of 2-18 GHz and an EAB of 11.52 GHz(6.48-18 GHz)is *** excellent absorption is attributed to the BN layer that limits the electrical conduction of the ceramic composites while retaining the high loss of *** introduction of BN@CNTs causes the refinement of SiC grains,which provides plenty of interfaces and enhances the interface polarization *** work successfully solves the problem that PDCs pyrolyzed at elevated temperatures cannot be used as EMW absorption materials by applying BN coating on CNTs served as absorbers for *** results of this work greatly broaden the application scope of the PDC systems for EMW absorption.

关键词： Electromagnetic wave absorption Polymer derived ceramic BN@CNTs Harsh environment High pyrolysis temperature

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

Fragmentation process of soil aggregates under concentrated water flow in red soil hilly region with different land use patterns

引用

Journal of Mountain Science 2023年第11期20卷 3233-3249页

作者： WEN Li-li WANG Jin-yue deng Yu-song DUAN Xiao-qian Guangxi Key Laboratory of Forest Ecology and Conservation College of ForestryGuangxi UniversityNanning 530004China Guangxi Key Laboratory of Agricultural environment and Agricultural product safety College of AgricultureGuangxiUniversityNanning 530004China

The hilly area of red soil in the central subtropical region of China has a long history of severe soil erosion due to its abundance of water,heat,and intense agricultural and forestry *** Sandshale red soil area is hot and rainy,the local land utilization rate and replanting index are high,and the soil easily weathers and erodes,resulting in infertile and sandy soils,extensive soil erosion and large erosion,with far-reaching *** this study,the stability of soil aggregates was studied by the wet sieving method and Le Bissonais(LB)method in six land use patterns in the Sandshale red soil area,including natural forest(NF),Pinus massoniana(PM),Eucalyptus urophylla×***(EU),orchard(OR),wasteland(WL)and arable land(AL).The transport damage characteristics of the soil aggregates under concentrated water flow were analyzed by using the soil aggregates to simulate the soil surface roughness in the field using a steel scouring flume with a variable *** results showed that:(1)the total soil porosity of the natural forest was the highest,with 56.51%in A layer,which was 4.99%higher than the B layer,and the organic matter content ranged from 10.69 to 29.94 ***-1 and was highest in NF and lowest in AL;(2)the maximum mean weight diameter(MWD)obtained by the wet sieving method was 4.81 mm for natural forest,and the MWD was the lowest in OR and AL at *** MWD measured by the LB method was also highest in NF and lowest in *** contents of Fed and Ald have a strong correlation with the stability parameters of soil aggregates;(3)the Wr/Wi results for the six land use patterns were NF>PM>EU>WL>OR>AL;the NF had the strongest soil aggregate stability,followed by WL,PM and EU,and AL and OR had the weakest;the stability of soil aggregates gradually weakened as the soil depth *** analysis shows that forest land has high soil stability and obvious advantages in soil erosion *** the construction of artificial f

关键词： Soil aggregates Land use Aggregate stability Fragmentation process

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

A New Species of Hemiphyllodactylus Bleeker,1860(Reptilia:Squamata)from Hunan Province,China

引用

Asian Herpetological Research 2020年第3期11卷 183-193页

作者： Bing ZHANG Tianyu qian Xiangjin JIANG Bo CAI Xuejian deng Daode YANG Institute of Wildlife Conservation Central South University of Forestry and TechnologyChangsha 410004HunanChina Yueyan Branch of Hunan Dupangling National Nature Reserve Bureau Yongzhou 425300HunanChina Chengdu Institute of Biology Chinese Academy of SciencesChengdu 610041SichuanChina Hunan Normal University Changsha 410081HunanChina

A new species of gekkonid,Hemiphyllodactylus dupanglingensis ***.,is described based on six specimens from Hunan Province,*** new species is phylogenetically close to ***,***,***,and ***,and can be distinguished from its congeners by the following combination of cha racters:9-11 chin scales;postmental scales enlarged;9-12 infralabials,11-14 supralabials;14-16 dorsal scales and 10-11 ventral scales longitudinally arranged at the midbody contained with one eye diameter;a manual lamellar formula of 4-4-5-4 or 4-5-5-4 and a pedal lamellar formula of 4-5-5-5 or 5-6-6-4;21-25 continuous precloacal and femoral pores in males.

关键词： Hemiphyllodactylus dupanglingensis sp.nov. molecular phylogeny morphology slender gecko taxonomy

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

A comparison between novel Gd_(2)Zr_(2)O_(7)and Gd_(2)Zr_(2)O_(7)/YSZ thermal barrier coatings fabricated by plasma spray-physical vapor deposition

引用

Rare Metals 2021年第8期40卷 2244-2253页

作者： Ren-Bo Zhu Jian-Peng Zou Jie Mao Zi-qian deng Xiao-Feng Zhang Chun-Ming deng Min Liu School of Materials Science and Engineering University of New South WalesSydneyNSW2052Australia State Key Laboratory of Powder Metallurgy Central South UniversityChangsha410083China National Engineering Laboratory for Modern Materials Surface Engineering Technology and Key Laboratory of Guangdong for Modern Surface Engineering Technology Guangdong Institute of New MaterialsGuangzhou510651China

Spherical Gd_(2)Zr_(2)O_(7)hollow powders with a mean size of 8.8μm were fabricated as feedstock for thermal barrier coatings(TBCs)by *** single-ceramic-layer(SCL)Gd_(2)Zr_(2)O_(7)TBCs and double-ceramic-layer(DCL)Gd_(2)Zr_(2)O_(7)/YSZ TBCs with quasicolumnar structure were successfully fabricated by plasma spray-physical vapor deposition(PS-PVD).Tensile and water-quenching tests were applied to evaluate TBCs *** results show that adhesion strength of SCL Gd_(2)Zr_(2)O_(7)TBCs and DCL Gd_(2)Zr_(2)O_(7)/YSZ TBCs is36.5 MPa and 15.4 MPa,*** delamination of SCL Gd_(2)Zr_(2)O_(7)TBCs and DCL Gd_(2)Zr_(2)O_(7)/YSZ TBCs in the tensile test takes place at the middle and bottom of Gd_(2)Zr_(2)O_(7)layer,respectively,due to relatively lower fracture toughness of Gd_(2)Zr_(2)O_(7)*** 40 cycles of water-quenching test,DCL Gd_(2)Zr_(2)O_(7)/YSZ TBC surface keeps relatively intact,while SCL Gd_(2)Zr_(2)O_(7)TBC surface shows 20%visible destroyed regions,which demonstrates that DCL Gd_(2)Zr_(2)O_(7)/YSZ TBCs have a better thermal shock resistance than SCL Gd_(2)Zr_(2)O_(7)*** cracks in the SCL system propagate near thermally grown oxide(TGO)due to thermal mismatch and TGO growing stress,while cracks in the DCL system propagate in the Gd_(2)Zr_(2)O_(7)layer due to its relatively lower fracture toughness.

关键词： Plasma spray-physical vapor deposition Thermal barrier coatings Gd_(2)Zr_(2)O_(7) Thermal shock resistance 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

Mapping resistant QTLs for rice sheath blight disease with a doubled haploid population

引用

Journal of Integrative Agriculture 2015年第5期14卷 801-810页

作者： ZENG Yu-xiang XIA Ling-zhi WEN Zhi-hua JI Zhi-juan ZENG Da-li qian qian YANG Chang-deng State Key Laboratory of Rice Biology China National Rice Research Institute

Sheath blight（SB） disease,caused by Rhizoctonia solani Kuhn,is one of the most serious diseases causing rice（Oryza sativa L.） yield loss worldwide.A doubled haploid（DH） population was constructed from a cross between a japonica variety CJ06 and an indica variety TN1,and to analyze the quantitative trait loci（QTLs） for SB resistance under three different environments（environments 1-3）.Two traits were recorded to evaluate the SB resistance,namely lesion height（LH） and disease rating（DR）.Based on field evaluation of SB resistance and a genetic map constructed with 214 markers,a total of eight QTLs were identified for LH and eight QTLs for DR under three environments,*** QTLs for LH were anchored on chromosomes 1,3,4,5,6,and 8,and explained 4.35-17.53%of the phenotypic *** SB resistance allele of qHNLH4 from TN1 decreased LH by 3.08 cm,and contributed to 17.53%of the variation at environment *** QTL for LH（qHZaLH8） detected on chromosome 8 in environment 2 explained 16.71%of the variation,and the resistance allele from CJ06 reduced LH by 4.4 *** QTLs for DR were identified on chromosomes 1,5,6,8,9,11,and 12 under three conditions with the explained variation from 2.0 to 11.27%.The QTL for DR（qHZaDR8）,which explained variation of 11.27%,was located in the same interval as that of qHZaLH8,both QTLs were detected in environment 2.A total of six pairs of digenic epistatic loci for DR were detected in three conditions,but no epistatic locus was observed for *** addition,we detected 12 QTLs for plant height（PH） in three *** of the PH-QTLs were co-located with the *** results facilitate our understanding of the genetic basis for SB resistance in rice.

关键词： doubled haploid blight chromosomes sheath explained environments allele phenotypic facilitate

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

Regulating solid electrolyte interphase film on fluorinedoped hard carbon anode for sodium-ion battery

引用

Carbon Energy 2024年第6期6卷 200-215页

作者： Cuiyun Yang Wentao Zhong Yuqiao Liu qiang deng qian Cheng Xiaozhao Liu Chenghao Yang Guangzhou Key Laboratory for Surface Chemistry of Energy Materials New Energy Research InstituteSchool of Environment and EnergySouth China University of TechnologyGuangzhouChina

For the performance optimization strategies of hard carbon,heteroatom doping is an effective way to enhance the intrinsic transfer properties of sodium ions and electrons for accelerating the reaction ***,the previous work focuses mainly on the intrinsic physicochemical property changes of the material,but little attention has been paid to the resulting interfacial regulation of the electrode surface,namely the formation of solid electrolyte interphase(SEI)*** this work,element F,which has the highest electronegativity,was chosen as the doping source to,more effectively,tune the electronic structure of the hard *** effect of F-doping on the physicochemical properties of hard carbon was not only systematically analyzed but also investigated with spectroscopy,optics,and in situ characterization techniques to further verify that appropriate F-doping plays a positive role in constructing a homogenous and inorganic-rich SEI *** experimentally demonstrated link between the electronic structure of the electrode and the SEI film properties can reframe the doping optimization strategy as well as provide a new idea for the design of electrode materials with low reduction kinetics to the *** a result,the optimized sample with the appropriate F-doping content exhibits the best electrochemical performance with high capacity(434.53 mA h g^(-1)at 20mA g^(-1))and excellent rate capability(141 mAh g^(-1)at 400 mA g^(-1)).

关键词： F-doping hard carbon reduction kinetics sodium-ion batteries solid electrolyte interphase film

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

Effects of Spiral Magnetic Field on Structures Transformation and Macrosegregation of Sn-Pb Alloy

引用

Acta Metallurgica Sinica(English Letters) 2013年第3期26卷 345-351页

作者： Xingguo ZHANG qian ZHAO Jianshe GUO Qingyuan XING Liang deng Xiaoguang HOU Canfeng FANG School of Materials Science and Engineering Dalian University of Technology Baoshan Iron and Steel Company Limited

The effect of spiral magnetic field （SMF） on the solidification process of Sn-20 wt.%Pb hypoeutectic alloy was studied in this work. The temperature distribution and the macrosegregation together with the eutectic lamellar spacing during solidification were measured under different magnetic fields. The results indicate that the compositions in the top and bottom portions of the sample are nearly the same and the segregation phenomenon is basically eliminated by SMF at an exciting current of 125 A. The morphology of the primary phase transforms from coarse dendrite to rosette or ellipsoidal equiaxed crystal and the spacing of the eutectic lamellar increases from 1.6 to 3.9 μm when the exciting current increases from 0 to 125 A. Moreover, if the exciting current is high enough, the forced fluid flow caused by SMF will enhance the process of transition from lamellar eutectic structure to anomalous rod-like one.

关键词： Spiral magnetic field Forced convection Eutectic lamellar spacing Sn-Pb alloy Composition segregation

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

Photocatalytic H2 evolution improvement for H free-radical stabilization by electrostatic interaction of a Cu-BTC MOF with ZnO/GO

引用

Nano Research 2018年第2期11卷 979-987页

作者： Xifeng Shi Jiahui Zhang Guanwei Cui Ning deng Wen Wang qian Wang Bo Tang College of Chemistry Chemical Engineering and Materials Science Collaborative Innovation Center of Functionalized Probes for Chemical Imaging Key Laboratory of Molecular and Nano Probes Ministry of Education Shandong Normal University Jinan China

Metal-organic frameworks （MOFs） are self-assembled molecular containers that can encapsulate and stabilize short-lived reaction intermediates. In this study, the Cu-benzene-l,3,5-tricarboxylate （BTC） MOF was incorporated in a ZnO/graphene oxide （GO） photocatalytic system by electrostatic interaction, and the obtained assembly showed improved hydrogen evolution activity. Electron spin resonance analysis was used to detect and monitor free radicals in the photocatalytic system, and demonstrated that Cu-BTC MOF could stabilize and extend the lifetime of free radicals, increasing the chance of H. radical recombination to form H2. This work provides a new strategy for designing highly efficient photocatalysts.

关键词： metal-organic framework free radical stabilization H2 evolution photocatalysis electrostatic interactionassembly

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

Glypican-3 is a biomarker and a therapeutic target of hepatocellular carcinoma

引用

Hepatobiliary & Pancreatic Diseases International 2015年第4期14卷 361-366页

作者： Li Wang Min Yao Liu-Hong Pan Qi qian deng-Fu Yao Research Center of Clinical Medicine Affiliated Hos-pital of Nantong University Departments of Medical Informatics Medical School of Nantong University Departments of Immunology Medical School of Nantong University

BACKGROUND： The carcinogenesis of hepatocellular car- cinoma （HCC） is a multi-factorial, multi-step and complex process. Early diagnosis and effective treatments are of utmost importance. This review summarized the recent studies of on- cofetal glypican-3 （GPC-3）, a membrane-associated heparan sulfate proteoglycan, in the diagnosis and treatment of HCC. DATA SOURCES： English-language reports published from Iune 2001 to September 2014 were searched from MEDLINE. The key words searched included： GPC-3, biomarker, target and HCC. The sensitivity, specificity, positive and negative predictive values were extracted, and the effect of GPC-3 tar- geted therapy on HCC was also evaluated. RESULTS： GPC-3 plays a crucial role in HCC cell prolifera- tion and metastasis. It mediates oncogenesis involving signal- ing pathways during hepatocyte malignant transformation. GPC-3 expression is increased in atypical hyperplasia and cancerous tissues. GPC-3 levels in HCC patients are related to HBV infection, TNM stage, periportal cancerous embolus, and extrahepatic metastasis. The diagnostic accuracy of the combination of serum GPC-3 and alpha-fetoprotein in HCC is up to 94.3%. Down-regulation of GPC-3 with specific siRNA or anti-GPC-3 antibody alters cell migration, metastasis and invasion behaviors. The nude mice xenograft tumor growth is inhibited by silencing GPC-3 gene ***： Oncofetal GPC-3 is a highly specific biomark- er for the diagnosis of HCC and a promising target molecule for HCC gene therapy.

关键词： hepatocellular carcinoma glypican-3 signal pathways diagnosis targeted therapy

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

Overview on Submodule Topologies,Modeling,Modulation,Control Schemes,Fault Diagnosis,and Tolerant Control Strategies of Modular Multilevel Converters

引用

Chinese Journal of Electrical Engineering 2020年第1期6卷 1-21页

作者： Fujin deng Yongqing Lu Chengkai Liu qian Heng qiang Yu Jifeng Zhao School of Electrical Engineering Southeast UniversityNanjing 210096China

In the present scenario,modular multilevel converters(MMCs)are considered to be one of the most promising and effective topologies in the family of high-power converters because of their modular design and good scalability;MMCs are extensively used in high-voltage and high-power *** on their unique advantages,MMCs have attracted increasing attention from academic circles over the past *** studies have focused on different aspects of MMCs,including submodule topologies,modeling schemes,modulation strategies,control schemes for voltage balancing and circulating currents,fault diagnoses,and fault-tolerant control *** summarize the current research status of MMCs,all the aforementioned research issues with representative research approaches,results and characteristics are systematically *** the final section,the current research status of MMCs and their future trends are emphasized.

关键词： Capacitor voltage balancing control circulating current control fault diagnosis fault tolerant control modular multilevel converters modulating strategy modeling scheme submodule topology

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：