Co—Mn—Ni—Mg—Fe—O系材料的高温热稳定性

采用Ｃｏ－Ｍｎ－Ｎｉ－Ｍｇ－Ｏ系和Ｃｏ－Ｍｎ－Ｎｉ－Ｆｅ－Ｏ系这两种热处理电学特性相反的热敏材料进行复合得到Ｃｏ－Ｍｎ－Ｎｉ－Ｍｇ－Ｆｅ－Ｏ五元系材料，经热处理后电阻值的变化得到互补，使热敏电阻经高温热处理后稳定性有了很大的提高。     

热处理温度对Mn－Co－Ni厚膜热敏电阻浆料特性的影响

通过对Ｍｎ－Ｃｏ－Ｎｉ系过渡金属氧化物材料和导电相进行热处理，使Ｍｎ－Ｃｏ－Ｎｉ浆料制作的热敏电阻敏感特性和阻值分散性明显改善。     

热处理温度对Mn－Co－Ni厚膜热敏电阻浆料特性的影响

通过对Ｍｎ－Ｃｏ－Ｎｉ系过渡金属氧化物材料和导电相进行热处理，使Ｍｎ－Ｃｏ－Ｎｉ浆料制作的热敏电阻敏感特性和阻值分散性明显改善。     

热压烧结对Co－Mn－Ni－O热敏材料电性能的影响

研究了不同热压压力、热压方式对Ｃｏ－Ｍｎ－Ｎｉ－Ｏ热敏材料电性能的影响。热压烧结能够提高材料的电阻率及Ｂ值。Ｘ射线衍射分析表明，热压烧结材料有ＭｎＣｏ２Ｏ４、ＮｉＭｎ２Ｏ４和ＣｏＮｉＯ２三相组成。从扫描电镜照片可见，热压烧结材料晶粒细小、均匀、气孔率少，是提高其电性能的主要原因。调整热压压力可以有效地控制材料的电学参数     

热压烧结对Co－Mn－Ni－O热敏材料电性能的影响

研究了不同热压压力、热压方式对Ｃｏ－Ｍｎ－Ｎｉ－Ｏ热敏材料电性能的影响。热压烧结能够提高材料的电阻率及Ｂ值。Ｘ射线衍射分析表明，热压烧结材料有ＭｎＣｏ２Ｏ４、ＮｉＭｎ２Ｏ４和ＣｏＮｉＯ２三相组成。从扫描电镜照片可见，热压烧结材料晶粒细小、均匀、气孔率少，是提高其电性能的主要原因。调整热压压力可以有效地控制材料的电学参数     

添加剂对Fe—Cu系陶瓷材料负阻特性的影响

文章介绍了以Ｆｅ２Ｏ３和Ｃｕ２Ｏ为主成分的陶瓷材料的负阻特性，分析论述了Ｃｏ２Ｏ３、Ｂｉ２Ｏ３以及ＭｎＯ２掺杂对Ｆｅ－Ｃｕ系陶瓷材料负阻性能的影响，实验制得负阻系数ｎ＞１０，电压Ｖｐ＞２００的负阻性能良好的陶瓷材料。     

钨基重合金的重复烧结改善其冲击性能

钨基合金的一种热处理方法，既能改善其中冲击韧性，又保其抗拉强度和延伸率。这种方法包括钨基合金的保温，这种合金成份为８６－９９％Ｗ，掺杂至少１％的Ｎｉ、Ｆｅ、Ｃｕ、Ｃｏ和Ｍｏ的组合成份，温度范围为９５９－１３５０℃，保温时间为１分钟至２４小时，在水域油中淬火，重复保温和热处理步骤。     

微机图像处理系统和SEM对a—Fe2O3粉末的粒度分析

掺Ｓｎ的ａ－Ｆｅ２Ｏ３的粒度大小与它对ＣＯ的灵敏度密切相关，我们利用ＳＥＭ和计算机图像处理系统对它进行粒度分析，并讨论了作电镜粒度分析的样品制备方法和计算机图像分析的步骤，分析结果为得到理想粒度的ａ－Ｆｅ２Ｏ３的气敏材料提供了帮助。     

三元硅化物(Co_xNi_(l-x))Si_2薄膜的制备及特性

在Ｓｉ（１００）衬底上用离子束溅射方法淀积Ｎｉ,Ｃｏ,Ｔｉ薄膜,形成Ｃｏ／Ｎｉ／Ｓｉ,Ｎｉ／Ｃｏ／Ｓｉ和Ｃｏ／Ｎｉ／Ｓｉ等结构,通过氮气中快速热退火反应生成三元硅化物（ＣｏｘＮｉｌ－ｘ）Ｓｉ２。用ＡＥＳ,ＸＲＤ,ＲＢＳ沟道谱,ＳＥＭ及四探针等方法对（ＣｏｘＮｉｌ－ｘ）Ｓｉ２薄膜的物理特性和电学特性进行了测试,在Ｓｉ衬底上Ｃｏ,Ｎｉ多层膜经快速热退火可形成高电导的（ＣｏｘＮｉｌ－ｘ）Ｓｉ２薄膜,其电阻率在１５～２０μΩ·ｃｍ之间。Ｃｏ／Ｎｉ／Ｔｉ／Ｓｉ（１００）多层结构固相反应可以得到外延（ＣｏｘＮｉｌ－ｘ）Ｓｉ２薄膜。（ＣｏｘＮｉｌ－ｘ）Ｓｉ２的晶格为ＣａＦ２立方结构,晶格常数介于ＣｏＳｉ２和ＮｉＳｉ２之间。通过热处理和选择腐蚀等工艺,可在有ＣＭＯＳ图形的衬底上形成自对准的三元硅化物源漏接触和栅极互连图形。     

新型厚膜片式NTC热敏元件研究

作者以Ｍｎ（１＋ｘ）Ｃｏ（２－ｘ）Ｏ４作热敏基料，掺适量ＭｅＭｎ２Ｏ４添加物，有效地降低了热敏浆料的方组，改善了元件的热稳定性，使厚膜片式ＮＴＣ热敏元件达到了实用化的要求。     

An algorithm for noise suppression in dual energy CT material density images

Dual-energy material density images obtained by prereconstruction-basis material decomposition techniques offer specific tissue information, but they exhibit relatively high pixel noise. It is shown that noise in the material density images is negatively correlated and that this can be exploited for noise reduction in the two-basis material density images. The algorithm minimizes noise-related differences between pixels and their local mean values, with the constraint that monoenergetic CT values, which can be calculated from the density images, remain unchanged. Applied to the material density images, a noise reduction by factors of 2 to 5 is achieved. While quantitative results for regions of interest remain unchanged, edge effects can occur in the processed images. To suppress these, locally adaptive algorithms are presented and discussed. Results are documented by both phantom measurements and clinical examples.     

一维含单负材料光子晶体塔姆态的偏振特征

用磁单负材料A 和电单负材料B 组成了（ABBA）N 型一维光子晶体,利用传输矩阵法计算表明:在4 500~7 500 nm 间出现了3 个塔姆态。这些塔姆态有如下特性:入射角增加,其透射率不变,但半峰全宽度变窄,位置发生蓝移;在同一入射角时,TM 波塔姆态的蓝移量大于TE 波的。两介质的几何厚度同时增加时,TE 波和TM 波塔姆态的透射率和半峰全宽度均保持不变,但其位置都发生了红移。A 介质的介电常数A增加, TE 波和TM 波塔姆态的透射率均保持不变,但位置都发生了红移,其半峰全宽度都是先变窄再变宽。     

HgCdTe and other infrared material status in the ukraine

This is the first article to explain and illustrate the HgCdTe and other infrared (IR) material status in the Ukraine. It develops the background needed to understand the what and where of IR physics, devices, and materials, but does not pretend to be a comprehensive treatment of the subject as some data still remain classified.     

5 V正极材料LiCr0.5Mn1.5O4的电化学性能研究

采用柠檬酸络合法,制备了尖晶石结构的LiCr0.5Mn1.5O4正极材料。通过循环伏安、电化学阻抗谱、恒流充放电等方法,测试其电化学性能。结果表明:铬离子的加入不但增加了锰离子的平均化合价,有效抑制了Jahn-Teller效应,而且达到了5V的工作电压,稳定了尖晶石结构。材料存在一个活化过程,最大放电比容量达到了145.85mAh·g–1。经过30次充放电循环之后,放电比容量仍然稳定在121.33mAh·g–1,显示了良好的循环性能,为高电位锂离子电池应用提供了良好的应用前景。     

高温Al_(0.3)Ga_(0.22)In_(0.48)P/GaAsHBT电流增益的计算分析

建立了Ａｌ０．３Ｇａ０．２２Ｉｎ０．４８Ｐ／ＧａＡｓ异质结双极型晶极管（ＨＢＴ）中电流输运过程的模型,利用实验得到的材料特性参数进行了ＨＢＴ电流增益随温度变化的模拟．随着温度上升,小电流时电流增益下降较多,而大电流时电流增益基本保持不变．模拟表明,小电流下电流增益的下降主要是由ｅｂ结空间电荷区的复合电流随温度增加而造成的;而大电流下电流增益直至７２３Ｋ下降仍小于１０％．最高工作温度可达８４８Ｋ．由于采用的计算方法充分考虑了空间电荷区复合电流的影响,模拟结果较为符合实际情况,可为研制高性能ＨＢＴ器件所需材料     

A Highly Stretchable Cross‐Linked Polyacrylamide Hydrogel as an Effective Binder for Silicon and Sulfur Electrodes toward Durable Lithium‐Ion Storage

Despite the recent advancement in the in‐practical active materials (e.g., silicon, sulfur) in the rechargeable lithium‐ion energy storage systems, daunting challenges still remain for these high‐capacity electrode material candidates to overcome the severe volume changes associated with the repeated lithiation/delithiation process. Herein, developing a room‐temperature covalently cross‐linked polyacrylamide (c‐PAM) binder with high stretchability and abundant polar groups targeting the construction of high‐performance Si and sulfur electrodes is focused on. The robust 3D c‐PAM binder network enables not only significant enhancement of the strain resistance for working electrodes but also strong affinity to bonding with nano‐Si surface as well as effective capture of the soluble Li₂S_n intermediates, thereby giving rise to remarkably improved cycling performances in both types of electrodes. This rational design of such an effective and multifunctional binder offers a pathway toward advanced energy storage implementations.     

微电子器件封装中铜与金球键合的比较

铜球键合由于其成本低并且还可提供更高的可靠性潜力, 最终将成为一种更加流行的主要工艺。目前现有的少管脚数的封装已有一种从金丝向铜丝转变的倾向,但是其中有一些工艺问题,需要该工艺在先进封装中得到广泛的应用之前得以根本的解决。无论采用何种方法,人们可以期望在先进封装中降低成本将最终成为采用铜球键合的驱动力。     

Anomalously high tensile creep rates from thin cast Sn3.9Ag0.6Cu lead-free solder

The present paper compares the creep and microstructural changes during creep behavior of bulk and thin cast forms of Sn3.9Ag0.6Cu. The processing parameters of the thin cast material were selected to result in a very fine microstructure analogous to what occurs in very small size solder electronic interconnections. We found that the thin cast material is less creep resistant than the bulk material. A comparison of Ag element maps between as-crept bulk and thin cast material shows that the relevant climb process occurs in a very different environment in the bulk material as compared to the thin cast material. In the bulk material, the relevant climb process occurs within a finely dispersed intermetallic compound (IMC) eutectic, which covers broad areas within the material. In the thin cast material, the relevant climb process occurs primarily in the beta-Sn grains that continuously surround isolated, coarse IMC particles. This resulted in the activation energy of the bulk material being larger than that for the thin cast material. Finally, it is important to note that the strength deficiency of the thin cast material is persistent—once the material is cast in thin cast form, it will remain weak in comparison to the bulk material. Therefore, using data obtained from bulk material samples for the construction of thermomechanical models of very small scale solder interconnections is likely to result in significant, intrinsic errors.     

Improved nanocrystal formation,quantum confinement and carrier transport properties of doped Si quantum dot superlattices for third generation photovoltaics

An all‐Si tandem solar cell has the potential to achieve high conversion efficiency at low cost. However, the selection and synthesis of candidate material remain challenging. In this work, we show that the conventional ‘Si quantum dots (Si QDs) in SiO₂ matrix’ approach can lead to the formation of over‐sized Si nanocrystals especially when doped with phosphorous, making the size‐dependent quantum confinement less effective. Also, our investigation has shown that the high resistivity of this material has become the performance bottleneck of the solar cell. To resolve these matters, we propose a new design based on Si QDs embedded in a SiO₂/Si₃N₄ hybrid matrix. By replacing the SiO₂ tunnel barriers by the Si₃N₄ layers, the new material manages to constrain the growth of doped Si QDs effectively and enhances the apparent band gap, as shown in X‐ray diffraction, Raman, photoluminescence and optical spectroscopic measurements. Besides, electrical characterisation on Si QD/c‐Si heterointerface test structures indicates the new material possesses improved vertical carrier transport properties. Copyright © 2011 John Wiley & Sons, Ltd.     

Characteristic modes for dielectric and magnetic bodies

A theory of characteristic modes for material bodies, both with and without losses, is developed. For loss-free bodies, the modes consist of a set of real characteristic sources which diagonalize the generalized network matrix for the body, and a set of characteristic fields which diagonalize the scattering matrix. Most of the properties of these modes remain the same as those of the corresponding modes for perfectly conducting bodies. For lossy bodies, the corresponding modes have complex characteristic sources. However, in the lossy case there also exists a set of real characteristic sources which diagonalize the generalized network matrix, but their fields do not diagonalize the scattering matrix.