模外装饰自动换膜机构设计

基于模外装饰工艺原理,对模外装饰自动换膜机构进行了详细设计,其中包含抚平轮和夹紧轮部分、机构固定部分、机架部分和裁刀部分。抚平轮和夹紧轮部分由抚平轮、夹紧轮、轴承、轴承套和摇杆等组成;机构固定部分由电机、压块、压块杆、轴承盖和摇杆等组成,机架部分由滚动导轨副、底板、滚珠丝杆副、步进电机、滚筒支架等组成;裁刀部分由侧板、导向杆、滑块和驱动电机组成。该套模外装饰自动换膜机构能够满足设计要求和实际需要。     

Generalized Orowan-Petch Plot for Brittle Fracture

The fracture of brittle solids is considered to be based on a defect configuration consisting of a stress concentrator, in our case a hemispherical pore, and a starter crack, in our case either a semicircular crack, a circular crack, or a circumferential crack. Computation of the stress field, application of the relevant weight functions, and an averaging scheme based on the assumption of a virtual crack increment provides stress intensity factors for all defect configurations considered. A normalization scheme yields a generalized version of the Orowan-Petch plot in the form of a normalized strength to normalized defect size relationship.     

Monitoring the oxidative modification of lipoprotein(a) by capillary zone electrophoresis

Lipoprotein(a) [Lp(a)] is a recognized risk factor for atherosclerotic cardiovascular disease. It is made of a lipoprotein particle containing apoB100 linked by a single disulfide bridge to apolipoprotein(a), a glycosylated protein with a variable mass. Some authors suggest that oxidative modification could explain the contribution of Lp(a) in the development of atheromatous lesions in a comparable way to low‐density lipoproteins (LDL). Recently, the use of capillary electrophoresis to measure the variations in the relative electrophoretic mobility (REM) of LDL subjected to copper oxidation has been proposed. The aim of this work is to employ this method also to monitor the copper‐induced oxidative modification of Lp(a). Migration of Lp(a) was monitored by absorption at 200 nm in a 50 mmol/L tricine, 100 mmol/L methylglucamine, pH 9.7 run buffer. Contrary to the conventional slab gel methods, our procedure provides a rapid and reproducible means to measure the electrophoretic mobility of Lp(a) (migration time <10 min with a CV% <0.5).     

Diels-Alder Reactions with Some N-Substituted Maleimides

A series of endo-carbonyl-1,2-dihydro-(3,4,5,6-tetraphenyl)-N-substituted phthalimides ( 5a – e ) has been synthesized by the Diels-Alder reaction of tetracyclone ( 2 ) with some N-substituted maleimides ( 1a – e ). Decarbonylation of the adducts 5a , b afforded the dihydrophthalimides 6a , b . The dihydro adducts 7a , b and 8a , b were obtained when phencyclone ( 3 ) and 2,3-dimethylfurane ( 4 ) were allowed to react with maleimides 1a , b . Dehydrogenation of the dihydro adducts 5a , b , 6a , b , 7a , b , 8a , b yielded the adducts 9a , b , 10a , b , 11a , b , 12a , b , respectively. The dihydro adducts 6a , b , in contrast to the dihydro adducts 7a , b , reacted further with one molecule of a dienophile to provide the dihydro adducts 14a , b , 15a , b and 16a , b . The dihydro adducts 16a , b , were also obtained in one step when one molecule of 2 was allowed to react with two molecules of each of the N-substituted maleimides 1a , b .     

Gravity draining of a yield-stress fluid through an orifice

We study the draining of a yield-stress fluid from a vertical vessel having a hole or a tube at its bottom. In order to understand the basic process we first study the problem with a Newtonian fluid and show that the flow characteristics can be very well described by assuming that the flow is analogous to that through a straight conduit of given length. For a yield-stress fluid draining through a hole the behaviour is different: the flow stops when the pressure drop across the orifice falls to a finite value which increases as the yield stress of the fluid increases or the hole radius R decreases. All the data collapse onto a master curve when plotted in terms of dimensionless numbers involving a characteristic length which is a function of R. We deduce an empirical model for the flow characteristics in such a case. When a length of tube is added after the hole we show that the characteristics of the flow are similar to those for flow through a straight conduit with an equivalent length equal to the tube length plus a fixed additional length.     

GENERAL LINEAR PROCESSES:A PROPERTY OF THE EMPIRICAL PROCESS APPLIED TO DENSITY AND MODE ESTIMATION

Abstract. General linear processes do not usually satisfy strong mixing conditions. Therefore, we investigate the empirical process based on samples from such a general linear process by using a truncation argument and derive a local fluctuation inequality. It is well known that such a fluctuation inequality is of basic importance in the study of the empirical process. Here it is applied to obtain a rate of almost sure (a.s.) convergence for certain density estimators in the supremum norm. This extends a local result obtained by Chanda. As a direct corollary a rate of a.s. convergence for a mode estimator is obtained.     

Lipoprotein(a): Nonhuman primate models

Lipoprotein(a) [Lp(a)] is a low density lipoprotein which has apo(a) disulfide-linked to apoB100. Apo(a) has recently been shown to have a striking homology with plasminogen, a knowledge that has stimulated a lot of interest in the mechanism of atherogenicity and thrombogenicity of this lipoprotein particle. Several studies have documented the presence of Lp(a) in nonhuman primates with particular reference to the rhesus monkeys and baboons. The Lp(a) of rhesus monkey is structurally very similar to that of humans, except for the absence of kringle V and the amino acid composition of the catalytic region. The Lp(a) of nonhuman primates, like their human counterparts, exhibit a wide range of interindividual plasma levels and also a wide size polymorphism of apo(a). Nonhuman primates appear to represent a good model for the study of the structure and biology of Lp(a).     

Simulation of the vapor explosion of tin and aluminum oxide fragments in water

The vapor explosion process involves an explosive phase change from a thin liquid film into a vapor with a dramatic change in material properties across a high-pressure shock wave. The energy released during the explosion process can reach a level of chemical explosions associated with detonating high explosives. Because no fuel-air chemical reaction is needed for initiating a vapor explosion, the process can be considered as a green reaction that generates zero pollutants. However, the phase change that accompanies a thousand-fold increase in the vapor volume during the rapid film evaporation is a natural consequence of a sudden change in density across the phase front; this feature closely resembles the process of blast wave generation. The high-pressure vapor produced without a chemical reaction expands as a spherical wave at a uniform velocity predicted through the Rankine-Hugoniot shock conditions. In this paper, a new methodology based on a simple shock wave and a phase field theory is proposed to formulate the vapor explosion process.     

Effects of catalyst and vehicle in coal liquefaction

Experiments have been carried out, using a semi-batch reactor equipped with a consecutive sampling device, to clarify the effects of catalysts and vehicles in the coal liquefaction process. The results show that a vehicle has a significant effect during preheating, unlike a catalyst which is not effective at this stage. A catalyst is more effective in promoting liquefaction under reaction conditions of 450°C and ≈ 20 MPa than is a vehicle. A vehicle higher in hydrogen donation increases the yield of oil even if a catalyst is present, providing a multiplier effect. In the development of a direct coal liquefaction process, therefore, selection of a vehicle is as important as that of a catalyst.     

Treatment for improving flame retardancy of wool and minimizing toxic gas evolution in burning

A treatment involving formaldehyde, a reducing agent, and a boron-containing compound of a wool shag carpet imparted to it a flame-retardancy effect that was effective after the seventh but not the eighth shampoo. This treatment also decreased the concentration of carbon monoxide and hydrocyanic acid generated in the products of combustion by at least a factor of 2. Analogous treatment of a wool flannel fabric produced a 15–22% sample area shrinkage and imparted a flame-retardancy effect that was still effective after a 2-hr cold water rinse.     

Thermal conductivity of polymer filled with carbon materials: Effect of conductive particle chains on thermal conductivity

Thermal and electric conductivities of polyethylene and poly(vinyl chloride) filled with carbon materials over a wide range are measured in order to study the effect of formed conductive particle chains on thermal conductivities of the composites. With increase of content of carbon particles, the amount of formed conductive chains exponentially increases and the conductive chains tend largely to increase thermal conductivity of a composite. Some models proposed to predict thermal conductivity of a composite in a two-phase system could not be applied to the system with high volume content of particles. In this study, a new thermal conduction model is proposed to correctly predict thermal conductivity of a composite which contains various amounts of particles ranging from a small content, to the region in which conductive chains largely effect a thermal conductivity of a composite. Thermal conductivity of a polymer filled with high volume content of particles largely decreased with a rise in temperature. This phenomenon can be referred to as a PTC phenomenon in thermal resistance.     

Templating of crystallization and shear-induced self-assembly of single-wall carbon nanotubes in a polymer-nanocomposite

We report the appearance of a novel self-assembling of a fraction of single-wall carbon nanotubes (SWCNT) within a SWCNT-polymer nanocomposite subjected to flow fields upon injection molding processing. By combining X-ray diffraction and Raman spectroscopy techniques, both working on a microfocus fashion, we probe that a fraction of the thinnest SWCNT self-assembles into a rectangular lattice in the sample regions where the shear stress induces the highest levels of nanotube aggregation. Additionally, we demonstrate that a modest amount in weight of nanotubes is enough to template the morphology of crystallization during flow providing a method to obtain a highly desirable fiber-like morphology.     

Non-Destructive Reliability Analysis of a Bridgewire Fuze Head

In this paper a novel method to determine the reliability of a bridgewire fuze head is proposed. It is assumed that a bridgewire will respond positively to a current pulse if the bridgewire temperature exceeds a critical value as a result of the pulse. To calculate the bridgewire temperature the distributions of four thermal parameters that characterize the electrothermal response of a bridgewire fuze head are used. Preliminary results indicate that this novel approach is in agreement with classical methods. Furthermore, one needs to test a limited amount of items and only a fraction of the tested items is destroyed.     

国内外己内酰胺生产现状及市场分析

世界上最大的5家己内酰胺生产商是德国BASF公司,生产能力为55.5万T/a;荷兰DSM公司,生产能力为42.0万t/a;美国Allied-Signal公司,生产能力为32.7万t/a;日本宇部兴产公司,生产能力为26.8万t/a;日本东丽公司,生产能力为17.0万t/a。这5家公司的已内酰胺生产能力合计为174万t/a,约占世界总产量的50％。中国目前有4套己内酰胺生产装置,岳阳巴陵鹰山石化厂,2000年生产能力为7万t/a;南京东方公司,生产能力为6万t/a;石家庄化纤公司,生产能力为5万t/a;浙江巨化公司锦纶厂,生产能力为0.45万t/a,全国合计年生产能力为18.45万t/a。国外己内酰胺的主要消费领域为纤维、工程塑料和食品包装膜;国内已内酰胺的主要消费领域为帘子布、民用丝、工程塑料,所占比例分别为70％、28％、2％。国内己内酰胺需求一直大于国内产量,但由于技术力量薄弱、资金有限及下游产品结构不合理等原因制约了己内酰胺的应用,目前国内的已内酰胺主要应用在中低档产品中,高档产品所需己内酰胺仍要依靠进口。     

Fireclay mortar with a casting binder as a plasticizing additive

A composition of a fireclay mortar with a casting binder as a plasticizing additive is described. Results of a study of the properties of a mortar of grade MSh39 with a composite plasticizing agent (soda ash+LST) and a casting binder are presented. It is established that use of a casting binder in the composition of a fireclay mortar increases the adhesion between the mortar and the refractory, decreases the thickness of the joint, and simplifies the production process of the mortar. Translated from Ogneupory i Tekhnicheskaya Keramika, No. 2, pp. 35–36, February, 1998.     

Reactions with the arylhydrazones of some α,β-diketoesters

Treatment of the α, β-diketo-ester-α-arylhydrazones 1a–e and 2a–d with GRIGNARD reagents results in the formation of the ketocarbinols 3a–h and 4a–g , respectively. The arylhydrazones of ethyl mesoxalate 5a–e react with phenylmagnesium bromide to yield compounds 3a–e . A novel synthesis of α-arylazo-β-arylchalcones 6a–e and their reaction with hydrazines are reported. Whereas the arylhydrazones 10a, b, 2a, b, d, 13a–c and 14a–c react with piperidine and formaldehyde to yield the MANNICH bases 11a, b, 12a–c and 15a–c , compound 5a was recovered unchanged.     

Zur Umkupplung von 4-Arylazo-2-pyrazolin-5-onen mit p-Chinondiiminkationen

Recoupling of 4-Arylazo-2-pyrazoline-5-ones with p-Quinonediimine Cations 4-Arylazo-2-pyrazoline-5-ones ( 1a – j ) readily undergo coupling reaction with p-quinonediimine cations ( 2a , b ) to form azomethin dyes ( 3a , b ). The dependence of the rate constants k_K of the dye formation on the substituents of 1a – j as well as on the ionic strength show that the rate-determining step of the coupling reaction is the formation of the intermediate 4 in a bimolecular reaction between the carbanions of 1a – j and p-quinonediimine ( 2a , b ). It became evident that the benzenediazoniumion ( 5a – j ) is eliminated in the reaction of 4 to 3a , b . Under the coupling conditions used, substituted benzene is formed in the reduction reaction of 5a , b by the p-phenylendiamine ( 7a , b ) or by the leuco dye ( 6a , b ).     

The Electrothermal Enhancement of Propellant Burning by Plasma Injection

A series of experimental demonstrations of plasma injection into a burning propellant interface is presented. The propellant is a nitro-guanidine based material in the form of a right cylinder with a bore along its central axis. It is ignited by a hot-wire system and, when a pre-set pressure is achieved, a second wire is exploded using a high-voltage capacitor discharge circuit. The second wire forms a plasma, precisely at, or well away from the burning interface. Comparing the pressure histories from these different geometries allows the effect of increased burning rate to be separated from Joule heating of the product gases. Analysis of these histories shows a pressure increase over that caused by Joule heating of the products.     

Synthese von Benzo[b]thioxanthenen

Synthesis of Benzo[b]thioxanthenes Benzo[b]thioxanthenes, heterocyclic compounds related to tetracenes and tetracyclines can be obtained by the reaction of 2H-benzo[b]thiete ( 1 ) and 1,4-naphthoquinones ( 3a–g ). The primary cycloadducts 4a–g undergo an autoxidation process leading to the quinones 6a–g . The dihydroxy compound 4e shows an additional isomerization by a tetrafold H transfer ( 4e → 5e ′). Another preparative route to benzo[b]thioxanthenes makes use of the cycloadditon reaction of 1 and 1,4-epoxynaphthalenes ( 7a–d ). The primary adducts can be transformed to the title compounds by catalytic dehydration processes ( 8a–d → 9a-d ). An alternate regioselective opening of the oxygen bridge can be performed by the action of trimethyliodosilane ( 8a → 10a ). Methylation of 9a furnishes the sulfonium salt 14a which rearranges in a strongly alkaline medium to 16a ; in the presence of oxygen ketone 17a is generated.     

Further studies on the high-speed gel-spinning of ultra-high molecular weight polyethylene

Summary The high-speed spinning technique has been applied to very elastic solutions of ultra-high molecular weight polyethylene in paraffin oil in an attempt to produce a strong fiber in a one-step process. At a winding speed of 4000 m/min a fiber was produced with a tensile strength of 2.3 GPa, a Young's modulus of 46 GPa and a elongation at break of 6.5%. This fiber could not be hot drawn anymore. At a winding speed of only 1 m/min the same solution yielded after spinning and hot drawing a fiber with a tensile strength of 7.2 GPa.