战术战斧导弹的五大新特点

战术战斧导弹(Block 4)是美海军下一代的巡航导弹，按计划将于2004年装备海军，计划从2002年开始的第一个5年内生产1343枚。这极大地补充了现在战斧Blcok 2／3导弹的库存。该导弹既可以由水面舰艇发射，也可以由潜艇发射，在“沙漠风暴”中第一次得以使用。战术战斧导弹将在以下几个方面的性能进行改进和提高：发射平台任务规划能力、飞行中重新定位、巡航、作战摧毁评估能力以及飞行中性能状态报告。     

Multifunctional hydrogels that promote osteogenic hMSC differentiation through stimulation and sequestering of BMP2

The extracellular environment controls many cellular activities thereby linking external material cues to internal cell function. By better understanding these processes, synthetic extracellular material niches can be tailored to present cells with highly regulated physical and/or chemical cues that promote or suppress selected cell functions. Here, poly(ethylene glycol) (PEG) hydrogels were functionalized with fluvastatin-releasing grafts and growth factor binding heparin domains to enable the dynamic exchange of information between the material and cells from the outside-in and inside-out (i.e., bidirectional signaling). By incorporating a fluvastatin-releasing graft and carefully controlling the dose and temporal release, materials were designed to promote bone morphogenic protein (BMP2) and alkaline phosphatase (ALP) production by human mesenchymal stem cells (hMSCs). When the release of fluvastatin was controlled to occur over 2 weeks, BMP2 and ALP production was increased 2.2-fold and 1.7-fold, respectively, at day 28 compared to hMSCs cultured in the absence of fluvastatin. By introducing a heparin functionality into the gel to sequester and localize the hMSC-produced BMP2, the osteogenic differentiation of hMSCs was further augmented over fluvastatin delivery alone. Osteopontin and core binding factor α1 gene expression was 6-fold and 4-fold greater for hMSCs exposed to fluvastatin in the presence of the heparin functionalities, respectively. These results demonstrate how multifunctional gels that interact with cells in a bidirectional manner can efficiently promote selected cell functions, such as the osteogenic differentiation of hMSCs.     

延时爆破物料抛掷模型试验

延时爆破物料抛掷模型试验Ｄ．Ｓ．普利斯等由于重视采矿活动中环境监测，因此在开采露天矿时应用新技术是必要的。一个重要的环境问题是地下水酸化，这是由于地层，如典型的页岩，含有高于平均水平的硫铁矿成分。地下水酸化在露天矿中明显加快，因为相对不透水的页岩层爆...     

化工厂建设成本概算

<正> 工程人员在详细设计新厂之前,往往需要对新厂的建设成本作一简要的概算。一种简便的概算方法是把同类型工厂的已知成本作为依据,并将已知工厂和计划建造工厂的生产能力之比自乘到R次幂。这种概算法被称为0.6次幂系数模型,在1947年首次用于设备成本概算,在1950年用于工厂成本概算。用于工厂成本概算的R系数范围比用于设备成本概算的R系数范围要宽得多。 这种初步概算方法对于没有高精确度要求的设计前成本概算是非常有用的。用这一     

由拱管组成的复合管段固定支架受力计算

根据工程设计的实践，介绍了由拱管和波纹补偿器所组成的复合管段的固定支架受力计算方法和注意事项。     

基于启发式规则优化的网页元素提取方法

网页信息提取方法中的启发式规则,是识别网页标签信息、利用网页节点分析结果、针对网页不同内容、完成信息提取的重要手段。本研究在对现有启发式规则进行研究分析的基础上,提出了几种优化的启发式规则,实现对网页标题、发布时间、来源以及正文内容等元素信息的精准提取。本研究进一步提出了运用编辑距离算法实现正文内容提取准确率的判定,并提出阙值优化方法,克服了正文提取中噪声节点多、内容识别不完全的缺陷,大大提高了提取的准确度。     

Real-time evaluation and visualization of learner performance in a mixed-reality environment for clinical breast examination

We investigate the efficacy of incorporating real-time feedback of user performance within mixed-reality environments (MREs) for training real-world tasks with tightly coupled cognitive and psychomotor components. This paper presents an approach to providing real-time evaluation and visual feedback of learner performance in an MRE for training clinical breast examination (CBE). In a user study of experienced and novice CBE practitioners (n = 69), novices receiving real-time feedback performed equivalently or better than more experienced practitioners in the completeness and correctness of the exam. A second user study (n = 8) followed novices through repeated practice of CBE in the MRE. Results indicate that skills improvement in the MRE transfers to the real-world task of CBE of human patients. This initial case study demonstrates the efficacy of MREs incorporating real-time feedback for training real-world cognitive-psychomotor tasks.     

我厂联醇改造的总结与体会

我厂是从1994年开始对产品结构进行调整，当时新建了年产5000t双氧水和3000t／a过碳酸钠生产装置。1996年6月在合成氨“四改六”的同时，增建了2台中600粗醇合成塔，形成年产1万t粗醇，建了1台中600预塔，1台中1000主塔，形成年产1万t精醇生     

φ2.2m×7m闭路粉磨系统的技术改造

常熟金猫方星水泥有限公司是年产30万t水泥的中型企业。近年来,为适应环保要求,决定停窑开磨,将原1台Φ2.2m×7m生料磨改造成水泥磨,加上原有的1台Φ2.2m×12m水泥磨,采用外购熟料来磨制水泥。Φ2.2m×7m的生料磨改为水泥磨后,台时产量仅有12t/h,产品细度不稳定。为了扭转这种局面,公司决定采用T-Sepax型三分离选粉机并对整个粉磨系统进行综合技术改造。经过几个月的生产实践,技改效果显著,台时产量一直稳定在19t/h左右,比表面积达到400m2/kg以上。1技改措施1.1改用三分离选粉机由于Φ2.2m×7m水泥磨是由生料磨改造而来,原配备的是转子式选…