用于生产优质纸张和商品浆的混合办公废纸的脱墨

混合办公废纸(MOW)是可回收纤维的一个主要来源。去除色料和胶黏物．一直是办公废纸脱墨浆作为漂白商品浆替代品的主要问题。通常的作法是利用复杂的工艺技术解决这个问题．其代价是设备投资和运行成本高。本文论述了北卡州立大学木材和造纸科学系混合办公废纸脱墨的研究并对其结果及应用进行了讨论。     

浅谈公路施工机械设备对沥青混凝土路面施工质量的影响

本文主要从路面施工机械设备的选型、各个施工环节中机械设备的状况,以及各种设备的性能参数的选择、调整对沥青混凝土路面施工质量的影响进行了分析,目的以科学的机械配置,合理的机械施工参数来提高施工质量.     

我国最大的金刚石生产基地—瓦房店50号金刚石矿

瓦房店金刚石股份有限公司50号金刚石矿目前是我国最大的金刚石生产基地。它的建成投产不论是建设速度、生产技术、工艺设备等都为我国金刚石采选业的发展提供了一些经验。生产的金刚石远销美国、比利时、日本、南朝鲜和港台等国家和地区,由于产品质量好,很受外商的欢迎。本文概括介绍50号金刚石矿采选生产过程、主要装备与今后展望。     

光伏并网系统的谐振抑制策略及无源阻尼选取方法

针对多端口光伏直流升压汇集系统中DC/DC换流器存在的谐振问题,提出了基于无源阻尼的谐振抑制策略.通过对比不同运行工况下的等效阻抗,揭示了DC/DC换流器内部的谐振机理.综合考虑谐振抑制效果和阻尼电阻有功损耗,采用电容支路串联阻尼电阻的方式,通过对比谐振频率点的等效阻抗幅值与相邻正常频率点的阻抗幅值,给出了阻尼电阻的取值范围,有效抑制了换流器阻抗匹配引起的谐振.所提谐振抑制策略在保证换流器有较高传输效率的前提下,有效地提高了光伏并网系统的稳定性.     

与花岗岩有关金属成矿系统的时-空-物结构初探

与花岗岩有关的矿床是金属矿产资源的重要来源,对该类矿床成矿作用的持续时间、成矿深度、成矿规模的研究等鲜有报道,但这些科学问题的解决却对找矿预测具有重要参考价值。本文对前人相关研究成果进行了初步总结认为：与花岗岩有关的成矿作用持续时间一般约为1 Ma,但也可持续更长时间;成矿深度一般不超过5～10 km;成矿系统的垂向延深一般5～10 km,水平延伸一般不超过10～30 km;热液矿化蚀变空间分带的内因可能主要是离子电位和离子半径的差异,围岩的热导率可能是矿化蚀变空间分带的主要外因之一。     

圆筒形囊式隔振器静态和动态特性研究

介绍了利用材料试验机测试囊式空气弹簧隔振器静态、动态特性的原理及方法,并对某试样进行了测试和分析。结果表明,囊式空气弹簧隔振器的额定荷载及额载静刚度与充气气压基本成线性关系,额载动刚度随气压的增加而变大,振动频率对动刚度影响不大。     

乳及乳制品中羟脯氨酸的快速测定

研究了一种快速测定乳及乳制品中羟脯氨酸含量的方法,该方法水解时间缩短为15min,分光光度法比色定量,方法的定量限为0.05μg/m L,具有良好的重现性,精密度RSD<4%,加标回收率为95%~105%,研究数据表明该方法可以快速准确鉴定出乳及乳制品中是否添加了皮革奶。     

Testing the robustness of two-boundary control policies insemiconductor manufacturing

A simulation model based on a real wafer fabrication is used to investigate the robustness of the two-boundary (TB) production control strategy to the existing uniform loading policy used in a semiconductor fab. Our findings confirm that the TB policy is the most robust of all when random interference, such as machine breakdowns and demand variations, exist. It is also observed that the performance of the wafer fabrication facility under investigation can be improved significantly in terms of reducing cycle time, decreasing work-in-progress (WIP), and cutting down inventory cost     

中国动漫博物馆钢结构抗震设计与分析

在结构设计中,抗震设计是必不可少的环节。以中国动漫博物馆为例,一层采用钢网格筒钢框架支撑(钢板剪力墙)结构,二层及以上采用钢框架支撑(钢板剪力墙)+跨层桁架结构,运用现行结构抗震理论和有限元模型,进行了动力时程和静力弹塑性分析。分析表明:该结构整体抗侧刚度较好,具有较好的抗震性能。     

Analysis of wafer fabrication facilities using four variations of the open queueing network decomposition model

We analyze three wafer fabrication facilities with four open queueing network decomposition models - Whitt (1983, 1985), and Bilran and Tirupati (1988), Suri >et al. (1993). In the first facility, which is located in North America, the values of cycle time and WIP inventory predicted by each model are about 10% higher than the actual values observed in the facility. The estimates are on the high side because managers and operators in the facility take special action to expedite production whenever queues become too large or small. These special actions cannot be incorporated into the open queueing network models. In the second facility, which is taken from the literature, the values of cycle time and WIP predicted by each model are about 5% higher than the values reported in the literature. An investigation at a third facility located in South-east Asia identified a common manufacturing practice that caused a model assumption to be violated. New insights into the models and directions for future research are identified. We find that two of the four open queueing network models are easy to apply and give good results for facilities like the ones studied in this paper. The other two models are complex and are likely to be better-suited for more complex facilities.