靶功率和基体偏压对BCN薄膜成分及结构的影响

利用直流磁控溅射技术制备了三元硼碳氮(BCN)薄膜,通过改变靶功率(70 W和210 W)和基体偏压(-50 V～-400 V)得到不同成分和组织结构的薄膜.采用X射线光电子能谱仪和傅立叶红外光谱仪分析了薄膜的成分和结构.结果表明:靶功率增加使得薄膜成分发生改变,而基体偏压改变对薄膜中各元素的原子百分含量几乎没有影响;基体偏压的增加会引起高能粒子对基体的轰击作用增强,有利于薄膜中B-N键的形成,而且轰击能量越高越有利于sp3杂化的B-N键形成.     

上海滨江森林公园一期工程

1项目概况上海滨江森林公园位于黄浦江长江交汇处,规划面积300万m2,于2004年第4季度开工建设,一期工程预计今年年底基本建成开放。这是本市近年来规划建设的最大的近郊森林公园。通过滨江森林公园和炮台湾公园的建设,将形成黄浦江与长江交汇处的标志性滨江景观,也是水路进入上海的门户景观。公园的建设可以进一步平衡城区绿地布局,缓解宝山和浦东高桥地区缺少特大型公园的现状,成为中心城区市民可以到达的最近的森林公园。滨江森林公园的规划设计以上海市园林设计院和英国阿特金斯公司设计(并融合其它方案进行优化、改进)的联合体方案为主,…     

Twin mirrors for laser interferometric gravitational-wave detectors

Gravitational-wave detectors such as Virgo and the laser interferometric gravitational-wave observatory (LIGO) use a long-baseline Michelson interferometer with Fabry-Perot cavities in the arms to search for gravitational waves. The symmetry between the two Fabry-Perot cavities is crucial to reduce the interferometer's sensitivity to the laser amplitude and frequency noise. To this purpose, the transmittance of the mirrors in both cavities should be as close as possible. This paper describes the realization and the characterization of the first twin large low-loss mirrors with transmissions differing by less than 0.01%.     

Grain Size Effects on the Mechanical Behavior of Open‐cell Nickel Foams

The dependence of the mechanical behavior of nickel foams upon their grain size was studied. First, the grain coarsening phenomenon which occurs during the processing of foams was analyzed. A metallurgical characterization of the grain growth during heat treatment was performed. The grain size effects on the mechanical properties was then studied, namely, via the Hall‐Petch law. The foam walls being very thin, roughly 10 μm in thickness, grain growth and mechanical behavior might be different compared with conventional materials. The present results obtained with foams were compared with literature data on bulk pure nickel and with nickel foils of 10 and 50 μm in thickness which are good candidates for the modeling of the cell walls. The EBSD technique allowed observing the absence of preferred crystallographic orientations for both foams and foils. A mechanical model in the spirit of that by Gibson and Ashby was finally presented incorporating the grain size effect on yield strength and hardening modulus. This model provided a good estimation of the experimental data.     

Book reviews

In many current semiconductor manufacturing operations, headcount is manually allocated periodically based on man-machine ratio. Attributed to non-optimised allocation of direct labour to operations/machines, considerable productivity loss occurs. The problem is further complicated by some dynamic and uncertain factors such as constantly changing production targets and work in progress, overlapped labour skills, and variability in manufacturing operations and labour absenteeism rates. Motivated by the needs in real practice, this study aims to develop a model for allocating a direct workforce among semiconductor manufacturing operations to meet production targets and maximise labour productivity. This paper presents a two-stage goal programming model for the headcount allocation problem. To enhance the model's pragmatic use, a queueing module is introduced to account for the interferences among the multi-machine operations. Computational experiments are carried out to evaluate the performances of the proposed algorithms and pilot runs are implemented in a factory. Finally, a prototype system is developed and has been proved to be useful in practice.     

Education in domestic violence

A baccalaureate-level, mandatory course on the social aspects of violence against women is being given as part of the curriculum at the Université du Québec à Rimouski. The course has been offered since 1990 and includes a complete array of teaching techniques such as lectures, simulations and role playing. Its aim is to impart knowledge, develop awareness, promote a change of attitudes and develop intervention abilities for nurses who may come in contact with domestic violence situations. Prior to implementation, an exploratory study was completed to determine student nurses' perceptions of domestic violence. Results indicate that, prior to taking the course, domestic violence was perceived as an individual problem. Respondents (26 female and 2 male) generally accepted society's prejudices of domestic violence as fact and ignored research results that pointed to the social realities. By the end of the course, the respondents' knowledge of the social aspects of domestic violence was better integrated. The authors conclude that specific training on domestic violence can modify false perceptions and help nurses develop the necessary competencies to deal with these situations.     

IL-10 inhibition of human prostate PC-3 ML cell metastases in SCID mice: IL-10 stimulation of TIMP-1 and inhibition of MMP-2/MMP-9 expression

The molecular mechanism by which IL-10 inhibits metastases was examined using a SCID mouse model. Human PC-3 ML subclones normally metastasize to the lumbar vertebrae (approximately 70% mice injected, n = 14/20) following intravenous injection in severe combined immunodeficient (SCID) mice. IL-10 treatment of the PC-3 ML cells (15 ng/ml for 36 h) and the SCID mice (0.03 mg/kg/day for 30 days) reduced the number of metastases to 5% of the mice (n = 1/20). More importantly, following discontinuation of IL-10 treatment on day 30, the mice remained tumor-free and mouse survival rates increased dramatically (from < 30% in untreated mice) to about 85% in IL-10-treated mice. IL-10 did not appear to alter the growth rates or colony-forming ability of the PC-3 ML cells in vitro. Likewise, the growth of subcutaneous tumors and established bone marrow metastases was not inhibited by IL-10 treatment of the SCID mice. However IL-10 may inhibit the production of matrix metalloproteases (MMP) and prevent the establishment of metastasis. We therefore examined the influence of IL-10 on PC-3 ML production of MMP-2/MMP-9 and the tissue inhibitors of metalloproteinases (TIMP-1/2). Enzyme-linked immunosandwich assays (ELISAs) revealed that IL-10 (15 ng/ml for 36 h) treatment of the PC-3 ML cells down-regulated MMP-2 and MMP-9 while up-regulating TIMP-1 (not TIMP-2) expression. Likewise, IL-10-treated mice exhibited similar changes in TIMP-1 and MMP-2/MMP-9 expression. The IL-10 effects were blocked by IL-10 receptor antibodies. In comparison to IL-10, IL-4 failed to influence metastasis or the expression of TIMP-1, TIMP-2, MMP-2 and MMP-9 by PC-3 ML cells. We suggest that IL-10-regulated increases in the molar ratio of TIMP-1/MMP-9 and TIMP-2/MMP-2 might inhibit processes critical to the establishment of bone marrow metastasis.     

Adenovirus enhancement of polyethylenimine-mediated transfer of regulated genes in differentiated cells

Efficient gene transfer is a prerequisite for analysing regulation of transfected promoters. We combined the DNA binding property of the cationic polymer polyethylenimine (PEI) and the potent endocytic activity of adenovirus in a PEI-DNA-adenovirus complex which provided efficient plasmid delivery in differentiated cultured cells. We transfected 3T3-F442A adipocytes, C2.7 myocytes and FAO hepatoma cells with a construct containing the simian virus 40 promoter fused to the chloramphenicol acetyltransferase (CAT) gene, using a combination of PEI and 200 p.f.u. per cell of replication-deficient type 5 adenovirus. Resulting CAT activities varied according to the cell type reaching about 0.6, 8 and 38 units/mg protein for respectively 3T3-F442A, FAO and C2.7 cells. Increases in transfection efficiencies were 140- to 300-fold when compared with those obtained with PEI alone. Then we tested physiologically regulated promoters: the phosphoenolpyruvate carboxykinase gene promoter in 3T3-F442A or FAO cells and the hexokinase II gene promoter in C2.7 myocytes. Gene expression was appropriately increased by clofibrate, dexamethasone and insulin for 3T3-F442A, FAO and C2.7 cells, respectively. Thus, the combination of PEI and adenovirus is a simple, efficient, inexpensive and versatile method of gene transfer which is applicable to several differentiated cells and provides a physiologically coherent transgene regulation. We name this method PEI-adenofection.