Tomographic optical breast imaging guided by three-dimensional mammography

We introduce a modified Tikhonov regularization method to include three-dimensional x-ray mammography as a prior in the diffuse optical tomography reconstruction. With simulations we show that the optical image reconstruction resolution and contrast are improved by implementing this x-ray-guided spatial constraint. We suggest an approach to find the optimal regularization parameters. The presented preliminary clinical result indicates the utility of the method.     

Ni镀层由晶态向非晶态结构转变的氢效应

采用对 A_3钢基体进行预渗氢、降低溶液 pH 值的方法,研究了在不同电流密度下 Watt 镀Ni 过程中镀层结构从晶态转变到非晶态的氢效应。     

暴露在VC气氛中的危险性评价

估计人们在VC气氛中暴露的致癌危险性问题,需要综合来自几个领域的毒理学研究。在实验室动物中,VC的药物动力学及VC的极限毒性物种的性质必须弄清楚。VC与临界大分子相互作用的潜势必须测定。最后,实验室动物对于在VC中长期暴露的反应以及所有人们在VC中暴露的数据必须评价。考虑这三种基于     

Ni-20Cr-Y_2O_3弥散氧化物微晶涂层及其高温氧化性能

采用高频电脉冲沉积技术在Ni 2 0Cr合金表面上沉积MGH75 4ODS合金 ,获得了Ni 2 0Cr Y2 O3 弥散氧化物微晶涂层。在 10 0 0℃空气中对Ni 2 0Cr合金及施加涂层的试样进行 10 0h的氧化实验。结果表明 ,微晶化和添加弥散氧化物 (Y2 O3)促进了铬发生选择氧化形成Cr2 O3 氧化膜 ,提高了合金的抗高温氧化性能和氧化膜的粘附性。用AFM ,SEM ,EDS和XRD分别对Ni 2 0Cr合金与Ni 2 0Cr Y2 O3 弥散氧化物微晶涂层的形貌、结构和成分进行了研究 ,讨论了弥散氧化物微晶涂层改善Ni 2 0Cr合金高温氧化性能的协同作用机理。     

TC4钛合金微弧氧化-溶胶凝胶复合涂层的制备及其抗高温氧化性能

为了提高钛合金的使用温度,设计并制备了一种微弧氧化(MAO)-氧化钇稳定氧化锆(YSZ)的陶瓷复合涂层。采用微弧氧化(MAO)技术在TC4钛合金基体表面原位生长出一层氧化铝陶瓷层(TM涂层),然后采用溶胶-凝胶法(Sol-gel)在MAO层的基础上制备低导热系数的钇稳定氧化锆(YSZ)涂层,最终制备出MAO-YSZ复合涂层(TMY复合涂层)。采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)和能谱仪(EDS)分析涂层的相结构、组织形貌和成分,并测定了TC4、TM涂层以及TMY复合涂层在700℃下的氧化动力学曲线。结果表明:TMY复合涂层外层以ZrO2为主,内层主要为Al2O3。具有TMY复合涂层的钛合金在700℃下氧化100h后其氧化增重仅为无涂层钛合金的14%,说明TMY复合涂层可以显著提高钛合金的抗高温氧化性能与使用温度。     

阴极等离子电解沉积Ni和Ni-Al_2O_3纳米涂层

采用电极移动液流式阴极等离子电解在304不锈钢基体上沉积Ni和Ni-Al2O3纳米涂层,研究了溶液组成和电参数对Ni和Ni-Al2O3涂层结构和性能的影响。涂层形貌观察表明,阴极等离子电解沉积的Ni和Ni-Al2O3涂层具有熔融后快速凝固的特征,涂层与基体具有冶金结合。根据XRD的衍射峰宽计算了涂层的晶粒尺寸,结果表明制备的涂层具有纳米结构。元素分析结果证明,Ni-Al2O3涂层中含有少量的纳米Al2O3颗粒,且表面的Al2O3含量比涂层中高。纳米Al2O3颗粒弥散在Ni中显著提高了涂层的显微硬度和耐磨性能。     

国产电解电容器用铝箔的发展与展望

本文简述了电解电容器铝箔的技术要求,回顾了上世纪80年代以来国产电解电容器用铝箔生产的发展过程。目前,电解电容器用国产铝箔的生产获得了新的发展机遇,并已进入快速发展的阶段,但仍然面临着巨大的挑战,相关产业结构的调整、顺应国际市场向环保型转化、产品质量的检测系统的建立与改进等都是在深入进行高、新技术开发的同时还需面对的重要课题。动员社会科研开发力量是相关企业获得技术创新的重要途径,各级政府的积极引导与支持是国产电解电容器铝箔产业获得更大发展的重要保证。     

熔盐膜电解渗涂

熔盐电解渗涂具有许多优点,现在人们已经能够在不同的基体上渗涂 Be、B、Al、Ti、V、Cr、Mn、Ni、Zr、Ce、Y 和其它稀土元素。但是高温熔盐的强烈腐蚀性造成熔盐电解渗涂很难扩大生产,美国国家材料咨询委员会所属涂层委员会曾建议不在这方面     

Large-scale synthesis of copper nanoparticles by chemically controlled reduction for applications of inkjet-printed electronics

Copper nanoparticles are being given considerable attention as of late due to their interesting properties and potential applications in many areas of industry. One such exploitable use is as the major constituent of conductive inks and pastes used for printing various electronic components. In this study, copper nanoparticles were synthesized through a relatively large-scale (5?l), high-throughput (0.2?M) process. This facile method occurs through the chemical reduction of copper sulfate with sodium hypophosphite in ethylene glycol within the presence of a polymer surfactant (PVP), which was included to prevent aggregation and give dispersion stability to the resulting colloidal nanoparticles. Reaction yields were determined to be quantitative while particle dispersion yields were between 68 and 73%. The size of the copper nanoparticles could be controlled between 30 and 65?nm by varying the reaction time, reaction temperature, and relative ratio of copper sulfate to the surfactant. Field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) images of the particles revealed a spherical shape within the reported size regime, and x-ray analysis confirmed the formation of face-centered cubic (FCC) metallic copper. Furthermore, inkjet printing nanocopper inks prepared from the polymer-stabilized copper nanoparticles onto polyimide substrates resulted in metallic copper traces with low electrical resistivities (≥3.6?μΩ?cm, or ≥2.2 times the resistivity of bulk copper) after a relatively low-temperature sintering process (200?°C for up to 60?min).     

Dissolution and re-crystallization processes in multiphase silicon stabilized tricalcium phosphate

Ultrasonically accelerated dissolution of multiphase silicon stabilized tricalcium phosphate powders in water or Earle’s balanced salt solution transforms the powders into needle-like calcium deficient apatite crystals with the c-axis (001) oriented along the needle. Ion exchange with the solution occurs primarily in the first hours of immersion. The transformation is driven by an interaction between the crystal surface and adsorbed water leading to the growth of crystallites which have the most stable surface configuration. First principles calculations of the surface energies of various hydroxyapatite surfaces with and without adsorbed water shows that depending on the ion concentrations in the fluid that determine the chemical potential of tricalcium phosphate, either Ca-rich (010) or stoichiometric (001) layers are the dominant surfaces. The higher the chemical potential, the more elongated in the (001) direction the crystallites become to minimize the total surface energy. The loss of a calcium Ca²⁺ compensated by the addition of two H⁺ is strongly favoured energetically on the (001) and Ca-rich (010) surfaces. A high concentration of excess Si at grain boundaries may be partly responsible for the rapid transformation of multiphase Si-TCP.