检索结果-南通市图书馆

Effect of rare earth on primary carbides in H13 die steel and their addition method:a review

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2024年第3期31卷 531-551页

作者： Jing-feng wang Lin-zhu wang Chao-yi Chen Xiang wang Fei Zhao School of Materials and Metallurgy Guizhou UniversityGuiyang 550025GuizhouChina Zhengzhou Railway Vocational and Technical College Zhengzhou 450000HenanChina Guizhou Provincial University Key Laboratory of High Performance Battery Materials Guizhou UniversityGuiyang 550025GuizhouChina Shougang Guiyang Special Steel Co. Guiyang 550005GuizhouChina

Larger-sized primary carbides lead to stress concentration during the application of H13 hot-work die steel,resulting in microcracks and fatigue *** earth was usually added to modify the carbides and *** existing literature is reviewed on the effect of rare earth on primary carbides in H13 steel.A comprehensive review on the effect of rare earth on the characteristics of primary carbides,i.e.,number,size,morphology,and thermal stability in H13 steel,was *** precipitation mechanism and nucleation of primary carbides with rare earth were *** position and form of rare earth in steel and their effects on alloying elements segregation were *** addition techniques of rare earth in H13 steel were compared,and the prospects for other uncommon rare earth and emerging technology were *** on the current references,it can be known that adding rare earth facilitated refined and dispersed primary *** size of primary carbides would be reduced,and their morphology would be improved because the rare earth inclusions formed in H13 steel can act as nucleation cores forγ-Fe orδ-Fe,refining the dendritic ***,the number of primary carbides at grain boundaries would be significantly ***,rare earth had little impact on thermal *** nucleation of primary carbides tended to be inhibited due to the modification of inclusions by rare earth which were likely to be nucleation cores for primary *** earth had been reported to affect the mechanism and process of primary carbide ***,the addition of rare earth can inhibit the segregation of alloying elements and carbon diffusion by ***,laboratory experiments and theoretical calcu-lations need to be conducted to study the states and evolution of rare earth steels.

关键词： Rare earth H13 die steel Primary carbide Nucleation Dendritic structure

Variations and determinants of tissue carbon concentration of 32 sympatric temperate tree species

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

Journal of Forestry Research 2024年第6期35卷 62-72页

作者： Jun Pan Jing Zhang Xingchang wang Xiuwei wang Qi wang Yankun Liu Yulong Liu Yunfei Diao Xiankui Quan Chuankuan wang Xiaochun wang Center for Ecological Research Northeast Forestry UniversityHarbin 150040People’s Republic of China Key Laboratory of Sustainable Forest Ecosystem Management Ministry of EducationNortheast Forestry UniversityHarbin 150040People’s Republic of China Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems South China Botanical GardenChinese Academy of SciencesGuangzhou 510650People’s Republic of China University of Chinese Academy of Sciences Beijing 100049People’s Republic of China National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and ManagementInstitute of Eco-Environmental and Soil SciencesGuangdong Academy of ScienceGuangzhou 510650People’s Republic of China Heilongjiang Institute of Ecology Heilongjiang Academy of ForestryHarbin 150040People’s Republic of China

Plant carbon(C)concentration is a fundamental trait for estimating C storage and nutrient ***,the mechanisms of C concentration variations among different tree tissues and across species remains poorly *** this study,we explored the variations and determinants of C concentration of nine tissues from 216 individuals of 32 tree species,with particular attention on the effect of wood porosity(i.e.,non-porous wood,diffuse-porous wood,and ring-porous wood).The inter-tissue pattern of C concentration diverged across the three porosity types;metabolically active tissues(foliage and fine roots,except for the foliage of ring-porous species)generally had higher C levels compared with inactive *** poor inter-correlations between tissue C concentrations indicated a necessity of measuring tissue-and specific-C *** concentration for almost all tissues generally decreased from non-porous,to diffuse-porous and to *** C was often positively correlated with tissue(foliage and wood)density and tree size,while negatively correlated with growth rate,depending on wood *** results highlight the mediating effect of type of wood porosity on the variation in tissue C among temperate *** variations among tissues were more important than that among *** findings provided insights on tissue C concentration variability of temperate forest species.

关键词： Carbon fraction Growth rate Temperate tree species Tissue density Wood porosity

Fusion of multiagent preference orderings with information on agent's importance being incomplete certain

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2007年第4期18卷 801-805页

作者： wang Jianqiang School of Business Central South Univ. Changsha 410083 P. R. China

The problem of fusing multiagent preference orderings, with information on agent＇s importance being incomplete certain with respect to a set of possible courses of action, is described. The approach is developed for dealing with the fusion problem described in the following sections and requires that each agent provides a preference ordering over the different alternatives completely independent of the other agents, and the information on agent＇s importance is incomplete certain. In this approach, the ternary comparison matrix of the alternatives is constructed, the eigenvector associated with the maximum eigenvalue of the ternary comparison matrix is attained so as to normalize priority vector of the alternatives. The interval number of the alternatives is then obtained by solving two sorts of linear programming problems. By comparing the interval numbers of the alternatives, the ranking of alternatives can be generated. Finally, some examples are given to show the feasibility and effectiveness of the method.

关键词： decision making fusion incomplete certain information preference ordering ternary AHP multiagent

Metasurface-assisted low-frequency performance enhancement of ultra-broadband honeycomb absorber based on carbon nanotubes

在线全文

学校读者我要写书评

暂无评论

Nano Research 2024年第9期17卷 8542-8551页

作者： Cai-liang wang Shuang Bai Pei-Yan Zhao Tao Zhou Hui-Ya wang Jun-Peng wang Luo-Xin wang Guang-Sheng wang School of Chemistry Beihang UniversityBeijing 100191China Aerospace Science and Industry Corporation of Wuhan Magnetoelectricity Co. Ltd.Wuhan 430070China College of Materials Science and Engineering Key Laboratory for New Textile Materials and Applications of Hubei ProvinceWuhan Textile UniversityWuhan 430200China School of Chemistry and Chemical Engineering Lingnan Normal UniversityZhanjiang 524048China School of Materials Science and Engineering Zhejiang Sci-Tech UniversityHangzhou 310018China

Here,we present a unique method to enhance the low-frequency absorption performance of a honeycomb absorber by integrating a *** geometrical dimensions of the proposed metasurface have been numerically *** introduction of the metasurface allows exploitation of its robust resonance and superior impedance matching in low-frequency bands,thereby improving microwave absorption *** incorporation of the metasurface does not impact the wave transmission performance of the honeycomb core absorber at high-frequency band,thus preserving its high-frequency *** broadens the absorption range,leading to an expanded *** results reveal that the composite absorber(CA)exhibits strong absorption performance with an incident angle stability up to 45°for both transverse electric(TE)and transverse magnetic(TM)*** absorption mechanism of the CA has been investigated by using an equivalent circuit model and electromagnetic field analysis.A prototype was designed,fabricated,and tested to validate the proposed *** simulation and measurement results demonstrate that the prototype can achieve an average absorption rate exceeding 90%across a 1.0-18.0 GHz *** study introduces an innovative technique for creating microwave absorbers for low-frequency wideband applications.

关键词： low frequency metasurface radar absorption impedance matching

A Nonorthogonal Joint Block Diagonalization Algorithm Avoiding Degenerate Solutions

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

Chinese Journal of Electronics 2017年第2期26卷 331-335页

作者： CHENG Guanghui wang Leijie wang Zhuande School of Mathematical Sciences University of Electronic Science and Technology of China

The joint block diagonalization algorithm is instrumental to the convolution blind signal ***,the nonorthogonal joint block diagonalization algorithm based on a Weighted least-squares(WLS) criterion sometimes converges to the degenerate or trivial *** is simple to avoid the trivial solution by adding some constraint on the de-mixing *** the degenerate solution is hard to be *** paper probes the phenomenon of the degenerate *** adding a new penalty function to the WLS criterion,an efficient algorithm which can avoid the degenerate solution is *** the theoretical derivation and numerical simulation,we can make the conclusion that the proposed algorithm is more robust and not sensitive to the square or non-square mixing matrix.

关键词： Degenerate solution Joint block diagonalization Blind source separation Convolution

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

热效应对纳米焊接界面结构的影响(英文)

强激光与粒子束 2015年第4期27卷 180-186页

作者：刘璇刘泽王亚荣赵波王世明张韬上海海洋大学工程学院上海201306 江苏师范大学物理与电子工程学院江苏徐州221116

采用分子动力学方法深入研究热效应对纳米焊接界面结构的影响。具体分析了碳管直径和时间的变化对界面结构的影响规律,并详细给出了1530K下的焊接过程。结果表明,除碳管(5,5)外,碳管(6,6),(7,7),(9,9),(11,11)中纳米线形成的时间分别为1... 详细信息

采用分子动力学方法深入研究热效应对纳米焊接界面结构的影响。具体分析了碳管直径和时间的变化对界面结构的影响规律,并详细给出了1530K下的焊接过程。结果表明,除碳管(5,5)外,碳管(6,6),(7,7),(9,9),(11,11)中纳米线形成的时间分别为13.8,14.6,17.5,19.6ps。纳米线是由单根或多根Ni原子链组成,碳管(6,6),(7,7),(9,9),(11,11)中Ni原子链数分别为1,3,7和16。界面结构包括内部焊接和外部焊接。内部焊接的临界直径由碳管(6,6)决定,其值为0.814nm。在同一时刻,大直径的碳管可获得更大的外部接触长度。外部接触长度的增长速率随碳管直径的增加而增大,接触长度的最大增长速率可达0.013nm/ps。最后确定了界面结构形成临界温度,发现对于相同直径碳管,外部焊接的临界温度高于内部焊接的临界温度,临界温度与碳管直径无关。

关键词：单壁碳纳米管纳米焊接临界温度纳米线

在线全文

学校读者我要写书评

暂无评论

日本扁柏生物学及其引种研究

林业科学研究 2000年第3期13卷 308-315页

作者：江泽平王豁然中国林业科学研究院林业研究所北京100091

日本扁柏是优良用材、荒山绿化和园林观赏树种 ,世界各国广为引种栽培 ,已成为我国长江中下游地区中、高山地带的重要造林树种。对其地理分布、生物生态学特性、栽培技术等进行了研究总结。结果表明 ,日本扁柏是一个喜温暖湿润的浅根性... 详细信息

日本扁柏是优良用材、荒山绿化和园林观赏树种 ,世界各国广为引种栽培 ,已成为我国长江中下游地区中、高山地带的重要造林树种。对其地理分布、生物生态学特性、栽培技术等进行了研究总结。结果表明 ,日本扁柏是一个喜温暖湿润的浅根性树种 ,生长快 ,适应性强 ,繁殖容易 ,病虫害少。适合中性至微酸性土壤 ,可耐 - 2 5℃低温。较喜光 ,幼时稍耐庇荫。春季日均温大于 10℃时开始萌动 ,超过 15℃时开始生长 ;生长具明显的坡向和坡位效应 ;树高速生期为 10～ 2 0 a,>5 0 cm·a-1;胸径速生期 2 0～ 30 a,>0 .6cm· a-1;材积速生期 30～ 40 a。可进行种子或扦插繁殖 ,结实有丰歉年 ,种子发芽率 30 %～ 40 %。造林密度为 2 5 0 0～ 45 0 0株· hm-2 ,以不超过 30 0 0株· hm-2为好。目前我国引种栽培日本扁柏的主要问题是 :( 1)遗传基础狭窄 ,需引进更多的种源和家系 ;( 2 )大多为纯林。

关键词：日本扁柏生态学引种栽培生物学特性

电子干扰飞机对抗警戒雷达组网系统的效果评估

在线全文

学校读者我要写书评

暂无评论

系统仿真学报 2008年第4期20卷 997-1001页

作者：申绪涧王国玉汪连栋戚宗锋中国人民解放军63880部队

在复杂的电磁环境下,如何有效地分析和评估远距离支援干扰对抗地面防空雷达网的效果具有重要的意义。分析了电子干扰飞机的运动给干扰效果造成的影响,以噪声压制式干扰效果评估为例,针对警戒雷达及其组网系统,在"有效干扰区"、"暴露区"... 详细信息

在复杂的电磁环境下,如何有效地分析和评估远距离支援干扰对抗地面防空雷达网的效果具有重要的意义。分析了电子干扰飞机的运动给干扰效果造成的影响,以噪声压制式干扰效果评估为例,针对警戒雷达及其组网系统,在"有效干扰区"、"暴露区"等传统评估指标的基础上,提出增加"干扰过渡区"作为评估指标,研究了相应的评估方法,并给出了干扰效果的定量评估结果。

关键词：电子干扰飞机噪声压制式干扰警戒雷达组网系统效果评估

Fuzhuan brick tea affects obesity process by modulating gut microbiota

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastrointestinal Pharmacology and Therapeutics 2022年第3期13卷 30-32页

作者： Zhi-Peng Li Dong-Hui Xu lian-Ping He Xin-Juan wang School of Medicine Taizhou UniversityTaizhou 318000Zhejiang ProvinceChina

The effect of Fuzhuan brick tea(FBT)on metabolism in obese mice is mediated by regulation of N-methyltransferase by aryl hydrocarbon *** expression of the phosphatidylethanolamine N-methyltransferase gene is regulated by many transcription factors,and those specific to this effect need further *** animal studies have been designed to observe the effects of a single drug or the sequential effects of drugs.A washout period should be included if different drugs(e.g.,antibiotics and FBT)are given to avoid or reduce additive effects or ***,most experimental studies performed in mice used only male ***,experience has revealed that the results of using only male mice are very likely to have sex differences.

关键词： Intestinal flora Mice Tea Sex bias Fuzhuan brick tea