Recapture of secondary electrons by the target in a DC planar magnetron discharge

In this paper we describe a simple two-dimensional model that allows the study of the individual secondary electron orbits in a DC planar magnetron discharge. Emphasis is on the recapture of secondary electrons by the target, which is enabled by their small initial energy, because this reduces the effective secondary electron yield as seen by the discharge. This reduction depends strongly on both the position along the race track and the gas pressure and it can be substantial for typical planar magnetron operating conditions. Our simple model allows to conclude that because of the sensitivity of the discharge on the secondary electron yield, the current-voltage characteristic, the spatial distribution as well as the pressure dependence of the planar magnetron discharge will be influenced by recapture.     

Behaviour of Ti Based on Si （111） Substrate at High Temperature in Oxygen

The behavior of Ti based on Si（lll） in oxygen under high temperatures（700 ℃, 800 ℃ , 900 ℃ , I 000 ℃ and 1 100℃） is reported. X-ray diffraction（XRD） and Fourier transform infrared spectroscopy （FTIR） are used to analyze the structure and composition of the samples annealing at different temperatures in oxygen ambience. It is found that raising temperature is helpful to the formation of both TiSi2 and TiO2 and helpful to the diffusion of Ti to Si substrate.     

低压配电智能监控终端的设计与实现

阐述了低压配电系统无功补偿的现状和特点,分析了无功补偿方式和低压终端无功补偿的特殊性.介绍了面向该应用对象的基于PIC单片机的配电智能监控终端设计.该配电智能监控终端具有高性能、低价位、高可靠性和配置灵活等特点.     

GIC－4117／HC1．7MV Tandetron上的MeV离子注入系统

利用通用离子公司（ＧＩＣ）的４１１７型１．７ＭＶＴａｎｄｅｔｒｏｎ离子束分析设备进行ＭｅＶ级离子注入。所注入的离子能量范围由５００ｋｅＶ到１０ＭｅＶ，离子的质量在２４０ｕ以下，某些元素的负离子束流强度在１５０μＡ以上。双向机械扫描技术可将离子均匀地注入样片。     

无功补偿及谐波治理方法浅谈

分析电网无功功率和高次谐波产生原因,浅谈治理方法,实现节能效果。     

高靶材利用率的新型磁控溅射器

在现代大型薄膜连续生产线中 ,其生产效率主要受以下两因数的影响 :溅射器的沉积速率和靶材的使用周期。本实验研制了一种圆筒形靶材绕溅射器中心轴线匀速旋转 ,并且与溅射器之间用螺丝固定连接的新型磁控溅射器。论述了新型溅射器的结构与组成 ,并给出实验结果与结论。其具有靶材利用率高、使用周期长、换靶时间短等优点。同时在反应溅射时避免在靶面上的形成介质层 ,提高了溅射过程的稳定性。     

Microstructure,Hardness and Corrosion Resistance of ZrN Films Prepared by Inductively Coupled Plasma Enhanced RF Magnetron Sputtering

ZrN fihns were deposited on Si（111） and M2 steel by inductively coupled plasma （ICP）-enhanced RF magnetron sputtering. The effect of ICP power on the microstructure, mechanical properties and corrosion resistance of ZrN films was investigated. When the ICP power is below 300 W, the ZrN films show a columnar structure. With the increase of ICP power, the texture coefficient （To） of the （111） plane, the nanohardness and elastic modulus of the films increase and reach the maximum at a power of 300 W. As the ICP Power exceeds 300 W, the films exhibit a ZrN and ZrNx mixed crystal structure without columnar grain while the nanohardness and elastic modulus of the films decrease. All the ZrN coated samples show a higher corrosion resistance than that of the bare M2 steel substrate in 3.5% NaCl electrolyte. The nanohardness and elastic modulus mostly depend on the crystalline structure and Tc of ZrN（111）.     

Hypoxia Suppresses Spontaneous Mineralization and Osteogenic Differentiation of Mesenchymal Stem Cells via IGFBP3 Up-Regulation

Hypoxia has diverse stimulatory effects on human adipose-derived stem cells (ASCs). In the present study, we investigated whether hypoxic culture conditions (2% O₂) suppress spontaneous mineralization and osteogenic differentiation of ASCs. We also investigated signaling pathways and molecular mechanisms involved in this process. We found that hypoxia suppressed spontaneous mineralization and osteogenic differentiation of ASCs, and up-regulated mRNA and protein expression of Insulin-like growth factor binding proteins (IGFBPs) in ASCs. Although treatment with recombinant IGFBPs did not affect osteogenic differentiation of ASCs, siRNA-mediated inhibition of IGFBP3 attenuated hypoxia-suppressed osteogenic differentiation of ASCs. In contrast, overexpression of IGFBP3 via lentiviral vectors inhibited ASC osteogenic differentiation. These results indicate that hypoxia suppresses spontaneous mineralization and osteogenic differentiation of ASCs via intracellular IGFBP3 up-regulation. We determined that reactive oxygen species (ROS) generation followed by activation of the MAPK and PI3K/Akt pathways play pivotal roles in IGFBP3 expression under hypoxia. For example, ROS scavengers and inhibitors for MAPK and PI3K/Akt pathways attenuated the hypoxia-induced IGFBP3 expression. Inhibition of Elk1 and NF-κB through siRNA transfection also led to down-regulation of IGFBP3 mRNA expression. We next addressed the proliferative potential of ASCs with overexpressed IGFBP3, but IGFBP3 overexpression reduced the proliferation of ASCs. In addition, hypoxia reduced the osteogenic differentiation of bone marrow-derived clonal mesenchymal stem cells. Collectively, our results indicate that hypoxia suppresses the osteogenic differentiation of mesenchymal stem cells via IGFBP3 up-regulation.