理性选择下的精细化设计:聚焦北京电视中心建设

与设计前卫、引来无数目光与争论的央视新大楼形成鲜明对比，建设中的北京电视中心在一种理性和务实的氛围中轮廓渐显。     

Research on quality improvement of the cross section cut by abrasive water jet based on secondary cutting

A manufacturing system comprises production processes and building services, both of which are supplied by different energy carriers as well as raw materials and water. These resources interact according to complex relationships and are converted into products for sale and waste flows. Holistic resource accounting allows the analyst to consider the dynamic relationships between these components, including the strong interdependence between energy and water, which has been called the energy-water nexus. Exergy analysis is a method that accounts for mass and both the quantity and quality of energy, while allowing analysis on a common basis, and for this reason, it is used increasingly to analyse resource consumption in manufacturing systems; however, it has rarely been used to consider water flows alongside energy and material flows. The main contribution of this paper is the presentation of modelling water flows in terms of exergy in the context of sustainable manufacturing. Using this technique in combination with previously developed exergy-based methods, the result is a truly holistic resource accounting method for factories based on exergy analysis that incorporates water flows. The method is illustrated using a case study of a food factory in which a 4.1% reduction in resource use is shown to be possible by employing anaerobic digester in an effluent water treatment process. The benefits of this technology option would have been underestimated compared to the benefits of waste heat capture if an analysis based on mass and energy balances alone had been used. The scientific value of this paper is the demonstration of the relatively high exergy content of effluent flows, which should therefore be regarded as potentially valuable resources. The analytical method presented is therefore of value to a wide range of industries beyond the food industry.     

Characteristics and applications of interplanetary coronal mass ejection composition

Science China Technological Sciences - In situ measurements of interplanetary coronal mass ejection (ICME) composition, including elemental abundances and charge states of heavy ions, open a new...     

基于高档精简指令集单片机的弹上记录仪

针对基于FPGA或51单片机与SRAM或FIFO实现的弹上记录仪存在着复杂度高、体积大等问题,提出基于高档精简指令集单片机与闪存实现弹上记录仪。该记录仪主要由单片机、闪存模块和地面控制平台构成,存储容量可编程最大为512MB;通过多级指令方式进行远距离检测,并采用了软件抗干扰技术。测试表明:基于高档精简指令单片机与闪存实现的弹上记录仪,具有体积小、操作简便、可靠性高和抗高冲击过载特点,能适应恶劣的飞行环境和经受高速着陆过程而不受损坏;该记录仪提供了一种弥补传统遥测在近地端遥测数据丢失的测试手段。     

Injury Mechanisms of Lactic Acid Bacteria Starter Cultures During Spray Drying: A Review

Lactic acid bacteria (LAB) starter cultures can be processed by many drying techniques, among which spray drying has great potential. However, injuries of LAB during spray drying lead to a low survival rate. The microbial injuries of LAB during spray drying are specifically induced by dehydration inactivation, thermal inactivation, and balance between the two. To reduce the drying temperature, new drying techniques based on spray drying were tried; that is, low-temperature vacuum–spray drying and spray–freeze drying.     

一种高效过滤亚微米级细颗粒的新液固过滤技术——表层过滤

论述一种新的可高效过滤液体中亚微米级细颗粒的表层过滤技术,分析了表层过滤技术的特点、过滤模式、表层过滤基本条件和设计计算中所必需的数学模型。介绍了表层过滤技术在我国工业生产上推广应用的概况。     

高密度聚乙烯装置旋液分离器堵塞原因及对策分析

30万吨/年高密度聚乙烯装置旋液分离器D3001A/B在生产的过程中容易堵塞。从旋液分离器顶部密度增加、反应器的内部固体含量(Solids-in)增加及淤浆加热器的热负荷增加等现象可以判断D3001A/B堵塞。根据不同反应模式和生产牌号,从反应器正常运行的参数和堵塞时的参数进行分析,并提出有效的优化措施,如降低顶部回流量,减小底部固体浓度和保证旋液分离器内壁光滑度等。     

吸附器的工程设计

详细介绍了实现变压吸附气体分离技术的关键设备—吸附器的设计,及其制造检验相关的要求。     

Synthesis and characterization of LTA zeolite with uniform intracrystal mesopores directed by bridged polysilsesquioxane monomer

An ordered mesoporous LTA zeolites (MLTA) have been synthesized in presence of the bridged polysilsesquioxane monomer (BS-1) as mesoporogen. The relatively well-defined small-angle X-ray diffraction peaks and nitrogen sorption isotherms with narrow pore size distribution centered at around 2.2 nm both indicated the presence of uniformly mesopores in MLTA samples. The scanning electron microscopy and transmission electron microscopy observations further confirmed that the uniform and partially interconnected intracrystal mesopores were randomly distributed throughout the globular particles with rugged surfaces. Interestingly, removal of the BS-1 resulted in uniform mesopore diameters that are nearly consistent with the molecular size of BS-1 (1.8 nm). ²⁹Si MAS NMR revealed that the BS-1 was linked to MLTA zeolite crystal surface through 2 Si–O bonds and 3 Si–O bonds before calcinations. Nitrogen sorption analysis showed that the mesoporosity in MLTA samples could be adjusted by adding different amounts of BS-1 in starting gels. Relative to conventional mesoporous materials, one obvious feature of MLTA is that the resultant mesopores were structured by the bridged polysilsesquioxane monomer instead of commercial polymers or micelles, which broad the routes in synthesizing of various mesoporous materials with controllable pore size distribution, adjustable mesopore volume, and large surface area.     

Performance evaluation of asphalt containing layered double hydroxides with different zinc ratio in the host layer

The effects of five layered double hydroxides (LDHs) with different zinc ratio on the physical and rheological properties, chemical components, and anti-UV aging performance of asphalt were evaluated. Results show that LDHs improve the deformation resistance of asphalt at high temperature. After UV aging, LDH-modified asphalts show the smaller changes of physical and rheological properties and chemical components in comparison with asphalt, indicating the improved UV aging resistance. By comparison, the LDHs with higher ratio of zinc in the layers have the more outstanding UV reflection ability, leading to a beneficial effect in improving UV aging resistance of asphalt.