卧螺离心机先进控制系统的应用

液压扭矩是卧螺离心机系统重要的运行指标参数,关系到离心机系统的安全、稳定运行。扭矩的过程优化控制及联锁保护控制的实现,适应了生产的需要,保证了离心机系统运行的稳定,提高了过程自动化水平。     

关于煤泥离心机工艺性能检测及操作要点的探讨

粗煤泥离心机因维护简单、运行可靠,一直受到各选煤厂的青睐;从入料性质、设备主要参数等方面对影响煤泥离心机脱水效果的因素进行了分析,结合运行效果采样化验,对煤泥离心机运行效果进行了分析评定,并提出保证设备运行效果的建议。     

卧式螺旋过滤离心机用于氯化铵脱水

针对国内使用离心机对氯化铵脱水存在的不足,提出选用卧式螺旋过滤离心机用于氯化铵脱水.介绍了该离心机的结构、特点,经试生产确定了离心机有关运行参数.     

延长泥渣离心机的运行周期

对泥渣离心机的运行周期明显缩短的原因进行全方位的剖析,通过采取相应的措施,延长了泥渣离心机运行周期,确保了装置安全、稳定、长周期运行.     

降低泥渣离心机高振动

通过对泥渣离心机高振动的原因进行全方位的剖析,采取相应的措施,稳定泥渣离心机的运行,同时延长泥渣离心机运行周期,确保装置安全、稳定、长周期、高效运行。     

卧式螺旋过滤离心机在氯化聚乙烯生产中的应用

介绍了卧式螺旋过滤离心机的材质及结构设计选型,确定了离心机的运行参数,并与其他酸性固液分离工艺进行了运行指标对比。     

煤制乙二醇亚硝酸钠离心机优化改型

新乡永金煤制乙二醇装置亚酯气制备系统中离心机操作繁琐、间歇进出料、设备运行效率低且晃动较大,职工劳动强度较大,严重影响了系统的安全稳定运行。经过技术论证,对离心机进行优化改型,不仅提高了离心机效率、降低离心机的振动、大大降低职工的劳动强度,而且降低生产成本、提高产品硝酸钠品质。     

PVC干燥系统离心机故障分析

根据PVC干燥工艺流程,介绍了离心机工作原理。并针对离心机常见故障,从工艺、安装、操作、维护保养等方面进行全面分析,保证离心机正常、高效运行。     

卧式螺旋过滤离心机在氯化聚乙烯生产中的应用

针对国内传统的釜式过滤、带式过滤机在氯化聚乙烯生产过程酸性固液分离存在的不足,提出了选用卧式螺旋过滤离心机。介绍了该离心机的材质及结构设计选型,确定了离心机的运行参数,并与其它酸性固液分离工艺进行了运行指标对比。     

HR500-N型活塞推料离心机使用总结

通过对HR500－N型离心机运行总结，着重介绍了HR500－N型离心机相对于WG－1200型离心机的使用优势及通过离心机换型所产生的经济效益。     

WH－800离心机推力计算及分析

通过文献［１］所述公式对ＷＨ－８００离心机在运行过程中所需要的必要推力、无用推力等方面进行分析计算，并提出为扩大其在制盐行业中的应用，提高其利用率而采取的措施。     

WH－800离心机推力计算及分析

通过文献［１］所述公式对ＷＨ－８００离心机在运行过程中所需要的必要推力、无用推力等方面进行分析计算，并提出为扩大其在制盐行业中的应用，提高其利用率而采取的措施。     

液滴撞击微结构疏水表面的动态特性

对去离子水滴撞击不同几何尺寸显微结构方柱和方孔状疏水表面的动态特性进行了研究。结果表明：当液滴以不同速度撞击微方柱疏水表面时,液滴展现铺展和回缩过程,且随着韦伯数（We数）增大,最大铺展直径增大,并伴随卫星液滴出现,但到达最大铺展直径的时间一致;而当液滴以相同的速度（We数相同）撞击间距不同的微方柱疏水表面时,液滴的最大铺展直径随着间距的增大而减小,且铺展过程会液滴浸润状态变得不稳定,发生由Cassie向Wenzel状态的浸润转变。当微方柱间距较小时,液滴受到的黏附功越小,越易发生向Cassie状态的转变;液滴撞击微方孔疏水表面时,液滴以规则的圆环状向外铺展和回缩,最后呈现近似规则的椭球状,不会发生向Wenzel状态的浸润转变,利用建立的物理模型对前述现象进行了分析。     

Inorganic/organic nanocomposite coatings: The next step in coating performance

Inorganic/organic hybrid materials have considerable promise and are beginning to become a major area of research for many coating usages, including abrasion and corrosion resistance. Our primary approach is to prepare the inorganic phase in situ within the film formation process of the organic phase. The inorganic phase is introduced via sol-gel chemistry into a thermosetting organic phase. By this method, the size, periodicity, spatial positioning, and density of the inorganic phase can be controlled. An important aspect of the inorganic/organic hybrid materials is the coupling agent. The initial task of the coupling agent is to provide uniform mixing of the oligomeric organic phase with the sol-gel precursors, which are otherwise immiscible. UV-curable inorganic/organic hybrid systems have the advantages of a rapid cure and the ability to be used on heat sensitive substrates such as molded plastics. Also, it is possible to have better control of the growth of the inorganic phase using UV curing. It is our ultimate goal to completely separate the curing of inorganic and organic phases to gain complete control over the morphology, and hence optimization of “all” the coating properties. Thus far, it has been found that concomitant UV curing of the inorganic and organic phases using titanium sol-gel precursors afforded nanocomposite coatings which completely block the substrate from UV light while maintaining a transparent to visible light. Also, it has been found that the morphology of the inorganic phase is highly dependent on the concentration and reactivity of the coupling agent. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004, in Chicago, IL.     

Trapping the western pine beetle at and near a source of synthetic attractive pheromone Effects of trap size and position

Western pine beetles were caught on unbaited sticky traps placed near a source ofexo-brevicomin, frontalin, and myrcene. Size of trap, distance and direction from the source of attractant, and height from the ground were varied. Significant differences in trap catch were observed in relation to each of the variables. Traps close to the source of attractant caught more beetles than traps farther from the source. Traps downwind of the source of attractant caught more beetles than did upwind traps. More males than females were trapped close to the source of attractant.Based in part on a thesis submitted by the senior author to the University of California, Berkeley, California, in partial fulfillment of the requirements for the degree Master of Science in entomology, December 1976. These studies were supported by the U.S. Forest Service and in part by the Rockefeller Foundation and a joint grant (NSF GB-34718/BMS 75-04223) from the U.S. National Science Foundation and the U.S. Environmental Protection Agency to the University of California. The findings, opinions, and recommendations are not necessarily those of the University of California or the funding agencies.Trade names and commercial enterprises or products are mentioned solely for information and do not constitute endorsement by the U.S. Department of Agriculture or University of California.     

一种自适应柱状密封气膜特性分析

提出一种自适应柱状气膜密封,构建气膜-密封环为研究对象,考虑了偏心间隙发散问题,并定义Rayleigh台阶对气膜周期的突变性,建立了气膜雷诺方程和膜厚变化函数关系式的动力润滑数值模型,获得了摩擦副气膜润滑特性,研究结果表明：气膜力随转速和压力升高而增加,泄漏量随压力升高而增加但是随转速增加而下降,说明密封内部压力流占主导地位。随后,利用曲面槽型雕刻技术,结合高速试验台对密封进行测试,结果表明：理论计算模型与试验结果吻合度较高,斜槽区域存在更多擦痕与磨损,说明斜槽浮动性弱于直列槽;但斜槽的切向流动小于直列槽,导致斜槽泄漏量小于直列槽。该研究成果为自适应柱状气膜密封的气体流动规律和应用提供了理论基础。     

Kinetics of organic solvent-soluble and native lipase

Organic solvent-soluble lipase was prepared with a synthetic detergent. The solvent-soluble lipase was presumed to be a complex of the enzyme and the detergent. To investigate the effect of the detergent attachment to the enzyme on the reaction properties, the kinetics of the solvent-soluble lipase and of the native lipase were estimated by using glycerides in a homogeneous solution of buffer and tetrahydrofuran. Analysis of the direct interaction between the enzyme and the substrate could serve to characterize the steric structure around the active site of the lipase. The K_m values also differentiated the solvent-soluble lipase from the native lipase. These findings show for the first time that the detergent surrounding the enzyme molecule may affect not only the solubility of the enzyme, but its kinetics as well.     

煤油贮箱冷氦鼓泡增压过程数值研究

火箭飞行过程中,约90 K的低温氦气用以加压室温下的煤油贮箱使煤油流出,保障发动机燃料供应。为尽可能减少氦气用量,设计低温氦气从液相中喷入,使得氦气在贮箱内上升过程先和液态煤油充分换热升温,再进入气相空间增压。但该过程可能引起两个不利的结果,首先浸没在煤油中的低温氦气管路表面可能结冰,结冰沉底或可能堵塞发动机滤网;其次氦气可能被煤油携带,从而排出口位置可能出现气液两相流。这两种情况都对火箭发动机稳定运行造成负面影响,因此是不允许的。对低温氦气在贮箱中心喷入和环向多孔喷入两种结构的气液两相流过程进行了数值研究,构建了基于Euler-Euler模型的两相传热非稳态模型,数值结果与地面实验观察到的现象进行了定性对比,定性验证了模型的准确性。重点考察了煤油排出过程两种喷入结构的气液两相流分布以及煤油结冰可能性。研究结果从机理上解释了实验现象,并为煤油贮箱增压排出方案设计提供了参考。     

Lipid distribution on textiles in relation to washing with lipases

Effectiveness of lipase in detergency was studied using three test soils (lard, artificial sebum, and olive oil) on a woven cotton fabric. Distribution of oily soil on fabrics was determined for three different treatments (unwashed, washed with detergent without lipase, and washed with detergent plus lipase). Osmium tetroxide was used to label lipid soil for analysis in the scanning electron microscope. Both longitudinal and cross-sectional backscattered electron images for unwashed samples showed that soil was present on surfaces of the cotton fibers and in interfiber spaces of the yarn bundle. Lard soiled samples had large deposits on the fabric surfaces, while artificial sebum and olive oil appeared more uniformly distributed throughout the textile. Oil was deposited in the interfiber capillaries of the yarn bundle and in the crenulation, secondary walls, and lumen of the fibers. Energy dispersive X-ray microanalysis was used to determine relative concentrations of oil at selected morphological locations within the fiber structure and at the fiber surface. Soil distributions within the fibrous structures differed with type of soil and laundry treatment. Backscattered electron images dramatically demonstrated the effect of lipase on cleaning. After washing with detergent plus lipase, yarn surfaces had much less residual soil; residual soil that remained was in the irregularities of the cotton fiber surfaces. Concentrations of oil in the secondary walls, crenulations, lumen, and the fiber surfaces were lower after lipase treatment for all three soils. While washing with detergent removed soil from the yarn and fiber surfaces and the crenulation of the cotton fiber, only the samples washed with detergent plus lipase had lower concentrations of soils within the secondary wall and lumen of the cotton fibers. Fabrics soiled with olive oil and washed with detergent plus lipase had the lowest concentrations of residual soil across the textile structure; the residual soil observed was mainly in the irregularities on the fiber surfaces.     

Modified dynamic matrix control

DMC (Dynamic Matrix Control) has been used successfully in industry for the last decade. It can deal with constraints and unusual dynamic behavior directly. It also shows a good control performance for the servo problem. Relatively, it can’t reject disturbances systematically. We propose a modified DMC method to control the regulatory process more efficiently. The proposed DMC method makes the control output by subtracting the estimated disturbance from the control output of the original DMC. Here, the disturbance is estimated by a new disturbance estimator. It shows better control performances than the original DMC.