共查询到20条相似文献,搜索用时 15 毫秒
1.
陶瓷,其耐热性、耐腐蚀性、功能性等引起人们重视,作为一种新材料而得到开发,其有用性得到了公认。所谓新材料,或明显提高原料纯度,或使其形状极端微细化、微粉化或者薄膜化,或使原料组合、制成合金,从而使材料性能得到空前的发挥。碳化硅(SiC)、硼(B)、氧化铝(Al2O3)等陶瓷也可使其形状变成又细又长的纤维状,从而使拉伸强度提高,使陶瓷的使用变得容易起来。本稿将就最近开发的轻质高强陶瓷纤维的性能加以介绍。 相似文献
2.
3.
4.
Ruobin Chang Wei Fang Jiaohui Yan Haoyang Yu Xi Bai Jia Li Shiying Wang Shijian Zheng Fuxing Yin 《材料科学技术学报》2021,62(3):25-33
The effect of Mo additions on the microstructures and mechanical properties of CoCrNi alloys was investigated,meanwhile,ab initio calculations are performed to quantitatively evaluate the lattice distortion and stacking fault energy(SFE).The yield strength,ultimate tensile strength,and elongation of(CoCrNi)97Mo3alloy are 475 MPa,983 MPa and 69%,respectively.The yield strength is increased by~30%and high ductility is maintained,in comparison with CoCrNi alloy.Besides the nano-twins and dislocations,the higher density of stacking faults is induced during the tensile deformation for(CoCrNi)97Mo3alloy.Ab initio calculation results indicate the mean square atomic displacement(MSAD)and SFE value of(CoCrNi)97Mo3alloy is 42.6 pm2and-40.4 mJ/m2at 0 K,respectively.The relationship between mechanical properties and MSAD,SFE for various multiple principal element alloys is discussed. 相似文献
5.
6.
针对薄宽带钢冷轧过程中易发多发的局部型中浪瓢曲缺陷,引入非均匀载荷宽度、弹性约束系数及平均张应力建立了屈曲变形的解析计算模型。应用能量最低原理对屈曲变形区域进行搜索求解,得到了局部型中浪屈曲临界条件(包括临界应力、屈曲波长和屈曲波宽),获得了其与非均匀载荷宽度、弹性约束系数、平均张应力的关系,并发现平均张应力是产生局部型中浪的重要影响因素。应用样条有限元方法对局部型中浪进行数值仿真分析,验证了屈曲解析计算方法的正确性。在实验轧机上进行了轧制研究,通过轧制获得了局部型中浪屈曲模态,对实验结果分析得到了相对应的屈曲临界条件,与解析法和样条有限元法结果基本吻合,证明了样条有限元计算方法与解析计算方法的正确性及其工程应用价值。 相似文献
7.
激励灯的灯头上有一大一小两个卡片,在灯座上对应的有两个槽,把激励灯装上去应当稳定不动.但由于槽的缝隙较宽,或固定灯泡的弹簧片疲劳使弹力减弱,致使灯泡受震动后容易前(指的是靠镜头一面)后幌动,这样会导致激励光刃变宽或不均匀,使还音含糊不清、失真. 相似文献
8.
9.
Lei Wang Shuangke Liu Jin Hu Xianan Zhang Xin Li Guanhua Zhang Yujie Li Chunman Zheng Xiaobin Hong Huigao Duan 《Nano Research》2021,14(5):1355-1363
Despite great progress of lithium-sulfur(Li-S)battery performance at the laboratory-level,both key parameters and challenges at cell scales to achieve practical high energy density require high-sulfur-loading cathodes and lean electrolytes.Herein,a novel carbon foam integrated by hollow carbon bubble nanoreactors with ultrahigh pore volume of 6.9 cm3·g?1 is meticulously designed for ultrahigh sulfur content up to 96 wt.%.Tailoring polysulfide trapping and ion/electron transport kinetics during the charge-discharge process can be achieved by adjusting the wall thickness of hollow carbon bubbles.And a further in-depth understanding of electrochemical reaction mechanism for the cathode is impelled by the in-situ Raman spectroscopy.As a result,the as-prepared cathode delivers high specific capacitances of 1,269 and 695 mAh·g?1 at 0.1 and 5 C,respectively.Furthermore,Li-S pouch cells with high areal sulfur loading of 6.9 mg·cm?2 yield exceptional practical energy density of 382 Wh·kg?1 under lean electrolyte of 3.5μL·mg?1,which demonstrates the great potential for realistic high-energy Li-S batteries. 相似文献
10.
Rebecca Vismara Corrado Di Nicola Rodrigo Gil-San Millan Kostiantyn V.Domasevich Claudio Pettinari Jorge A.R.Navarro Simona Galli 《Nano Research》2021,14(2):532-540
Hydrocarbons separation in petrochemical industries is a key,energy-consuming stage in the manufacture of high-quality added-value products—hence the need for more efficient materials and environmentally friendly methodologies to improve this process.In this context,we have studied the effect of metal-organic frameworks(MOFs)pore functionalization in hexane isomers separation,isolating the robust isoreticular zinc(ll)bipyrazolates Zn(BPZ),showing no pore decoration,Zn(Me2BPZ),the pores of which are decorated with apolar methyl groups,and Zn(BPZ(NH2)2),the spacers of which possess polar Lewis-basic functions(H2BPZ=1H,1'H-4,4'-bipyrazole;H2Me2BPZ=3,3'-dimethyl-1H,1'H-4,4'-bipyrazole;H2BPZ(NH2)2=3,5-diamino-1H,1'H-4,4'-bipyrazole;DMF=dimethylformamide).After characterizing Zn(BPZ(NH2)2)as per its crystal structure and thermal behaviour,and all the three MOFs as per their textural properties,we investigated,from the experimental and computational points of view,the impact of the square one-dimensional channels decoration on the separation of the hexane isomers,demonstrating the relevance of pore constrictions in the resolution of the title alkanes mixture. 相似文献
11.
Fei Pan Zhicheng Liu Baiwen Deng Yanyan Dong Xiaojie Zhu Chuang Huang Wei Lu 《纳微快报(英文)》2021,(3):22-38
Inspired by the nature,lotus leaf-derived gradient hierarchical porous C/MoS2 morphology genetic composites(GHPCM)were successfully fabricated through an in situ strategy.The biological microstructure of lotus leaf was well preserved after treatment.Different pores with gradient pore sizes ranging from 300 to 5μm were hierarchically distributed in the composites.In addition,the surface states of lotus leaf resulted in the Janus-like morphologies of MoS2.The GHPCM exhibit excellent electromagnetic wave absorption performance,with the minimum reflection loss of−50.1 dB at a thickness of 2.4 mm and the maximum effective bandwidth of 6.0 GHz at a thickness of 2.2 mm.The outstanding performance could be attributed to the synergy of conductive loss,polarization loss,and impedance matching.In particularly,we provided a brand-new dielectric sum-quotient model to analyze the electromagnetic performance of the non-magnetic material system.It suggests that the specific sum and quotient of permittivity are the key to keep reflection loss below−10 dB within a certain frequency range.Furthermore,based on the concept of material genetic engineering,the dielectric constant could be taken into account to seek for suitable materials with designable electromagnetic absorption performance. 相似文献
12.
中国电影资料馆珍藏着大量早期影片,其中许多具有珍贵的保存价值.1936年由蔡楚生编导、任光谱曲的<迷途的羔羊>是我国第一部以流浪儿童为题材的影片,也是我国儿童影片中的第一部有声片.此片在思想和艺术上都取得了突破,尤其是以童谣形式演唱的主题歌<月光光歌>感人至深,充分发挥了音乐的魅力,增强了整部影片的感染力.影片公映后,深受广大观众的欢迎和电影工作者的赞扬.七十多年过去了,当我们准备再次让它同观众见面时,却发现能够最真实、最原始记录影音效果的原底、声底片却出现了许多问题,给复制工作带来了空前的难度,这是我们从事资料影片复制工作三十多年来从未遇到过的难题.主要有以下几方面问题: 相似文献
13.
Qilin Wei Kiersten G.Guzman Xinyan Dai Nuwan H.Attanayake Daniel R.Strongin Yugang Sun 《纳微快报(英文)》2020,(3):169-178
Photothermal catalysis represents a promising strategy to utilize the renewable energy source(e.g.,solar energy)to drive chemical reactions more efficiently.Successful and efficient photothermal catalysis relies on the availability of ideal photothermal catalysts,which can provide both large areas of catalytically active surface and strong light absorption power simultaneously.Such duplex requirements of a photothermal catalyst exhibit opposing dependence on the size of the catalyst nanoparticles,i.e.,smaller size is beneficial for achieving higher surface area and more active surface,whereas larger size favors the light absorption in the nanoparticles.In this article,we report the synthesis of ultrafine RuOOH nanoparticles with a size of 2–3 nm uniformly dispersed on the surfaces of silica(SiOx)nanospheres of hundreds of nanometers in size to tackle this challenge of forming an ideal photothermal catalyst.The ultrasmall RuOOH nanoparticles exhibit a large surface area as well as the ability to activate adsorbed molecular oxygen.The SiOx nanospheres exhibit strong surface light scattering resonances to enhance the light absorption power of the small RuOOH nanoparticles anchored on the SiOx surface.Therefore,the RuOOH/SiOx composite particles represent a new class of efficient photothermal catalysts with a photothermal energy conversion efficiency of 92.5%for selective aerobic oxidation of benzyl alcohol to benzylaldehyde under ambient conditions. 相似文献
14.
Point defects in the crystal lattice of SiC,known as color centers,have recently emerged as one of the most promising single-photon emitters for non-classical light sources.However,the search for the best color center that satisfies all the requirements of practical applications has only just begun.Many color centers in SiC have been recently discovered but not yet identified.Therefore,it is extremely challenging to understand their optoelectronic properties and evaluate their potential for use in practical single-photon sources.Here,we present a theoretical approach that explains the experiments on single-photon electroluminescence(SPEL)of novel color centers in SiC p-i-n diodes and gives the possibility to engineer highly efficient single-photon emitting diodes based on them.Moreover,we develop a novel method of determining the electron and hole capture cross sections by the color center from experimental measurements of the SPEL rate and second-order coherence.Unlike other methods,the developed approach uses the experimental results at the single defect level that can be easily obtained as soon as a single-color center is identified in the i-type region of the SiC p-i-n diode. 相似文献
15.
<正>Justin Gaffrey,来自美国,多年前曾是位专职的厨师,而绘画只是他闲暇之余的兴趣,但一切就在欣赏了梵高的名画"向日葵"后发生了改变。Justin Gaffrey回忆说,当他看到那幅著名的作品时,就被它的质感深深吸引,于是便一头栽进鲜艳浓烈、立体奔放的绘画风格中。Justin Gaffrey从油画的基础概念开始延伸,最终发展出一套很有个人风格的立体绘画美学。他在画布上毫不手软地倾倒丙烯颜料,就像是装饰蛋糕的奶油一般,不计成本的抹上一层又一层,接着利用画刀来塑型,成品所呈现的质感有种半绘画半雕塑的鲜明立体感。 相似文献
16.
Capture NX2是尼康公司为其数码单反相机的RAW格式图片所研制的处理软件。相对于其他处理软件,Capture NX2既能对照片进行全局和局部的调整,还能识别保存在NEF数据中的所有相机设置, 相似文献
17.
18.
拍了好照片想放在醒目处与大家一起分享?想要日式、欧式风格的台灯?那就自己动手做一个既能展示作品,又可以增添房间温馨气氛的小灯箱吧!灯在家居饰品当中是一笔不菲的开销。小则几百,多则上万。我很喜欢灯,喜欢它那黄黄的光源和暖暖的色调,在漆黑的深夜,给人以温馨舒适的感觉。但是如果要替换家中灯的话也许要支付一笔不小的费用。市面上的灯不是太贵,就是不太合自己的品 相似文献
19.
如果要为天堂选择一片后海,那么,我相信它应该在马尔代夫。这里是印度洋中一串珍珠,是上帝悄悄制造的爱情伊甸园。马尔代夫这个名字起始于公元150年,泛指位于锡兰西岸的岛屿。当时许多来自东非、阿拉伯国家的船只,在航行中发现美丽、宁静的马尔代夫有适宜停泊的港口,人们也逐渐在岛上居住。虽然现在的天气很冷,但马尔代夫温暖的海风,依旧荡漾在我们的心头,久久不能散去。这里注定是我们甜蜜记忆中的一部分…… 相似文献