阻焊油墨脱落问题的分析及对策

本文分析了液态感光油墨脱落的原因,并提出了相应的对策。     

Studies on isolated corneocytes

The function of the stratum corneum is dependent on the functions of its constituent parts. This paper focusses on corneocyte dimensions and the implications of change in dimension for function. A technique in which it is possible to obtain a value for corneocyte thickness is described. The changes in corneocyte dimensions with age and site and after topical applications are documented.
Techniques which measure the rate of desquamation are also described. The rate of passive corneocyte loss has been estimated by counting the numbers of corneocytes shed into chambers fixed to the skin surface. In addition the corneocyte loss after a standardized rotational stimulus to the skin surface has been measured. Scanning and transmission electron microscope examination of corneocytes obtained by a scrub procedure is also described. A preliminary report on an immunological approach to the study of the biochemistry of corneocytes and stratum corneum is also included.
Etude de cornéocytes isolés     

Original semiologic standardized evaluation of stratum corneum hydration by Diagnoskin stripping sample

In a normal and healthy skin, the regular elimination of the superficial corneocytes, called desquamation, is a fundamental physiologic process intended to protect the barrier function of the skin. This invisible loss of corneocytes, individually or in small groups, is incessantly compensated by the divisions of the proliferative layer and the upward cellular maturation in order to maintain the harmonious renewal of the epidermis and the integrity of the stratum corneum. The harmony of this desquamation process is intimately conditioned by a sufficient hydration of the stratum corneum: (i) an abnormal desquamation leads to a disruption of the water barrier function and consequently to a dehydration tendency of the stratum corneum, and (ii) a cutaneous dryness (whatever the cause) is able to disturb the desquamation process. Protecting the water content of the stratum corneum has always been a major preoccupation of the cosmetic industry scientists. Consequently, the moisturizing properties of a cosmetic product are objectively measured by various explorations directly targeted on the hydration (corneometry) and on the level of the water barrier function (transepidermal water loss (TEWL) measurements), which depends directly on the skin hydration state. This intimate linkage of the desquamation process and the water content of the stratum corneum enable us to suggest an indirect assessment of the hydration from a direct study of the desquamation by examining a skin-stripping sample (D-Squames) by an optical microscope (linked to a computer). We will describe this already known technique and mainly its new and unpublished semiologic exploitation, named Diagnoskin, whose advantages are its simplicity and its reproducibility particularly interesting in the case of sequential appraisal of dermatologic or cosmetic treatments.     

Influence of cleansing on stratum corneum tryptic enzyme in human skin

Desquamation in human skin is a well-balanced process of de novo production of corneocytes and their shedding from the skin surface. The proteolysis of corneodesmosomes is an important step in the final desquamation process. In the degradation of these adhesion molecules, the stratum corneum tryptic enzyme (SCTE) plays a key role. In initial studies with extracts of porcine epidermis, SCTE was shown to be inactivated by low concentrations of sodium lauryl ether sulphate (SLES). These in vitro findings were supported by in situ results obtained by measuring the release of fluorescent dyes coupled to trypsin-specific substrates incubated on human skin cross-sections. Moreover, in further studies, it could be demonstrated that the SCTE activity in the human horny layer decreases after in vivo application of cleansing products containing SLES. After repeated washing of human volunteers with tap water, a standard market cleansing product (SLES/betaine system) or a new improved cleansing product (SLES/betaine/disodium cocoyl glutamate system), the specific SCTE activity was determined in extracts from the uppermost layers of the stratum corneum. It could be shown that after application of the new formula the remaining SCTE activity was significantly higher than after use of the standard market formula. This ex vivo approach has proven to be very helpful for measuring surfactant effects on human skin enzymes. Using this assay, we developed an improved shower gel formula, which leads to a significantly higher skin enzyme activity after application, compared to a standard market formula.     

Image analysis of scaly skin using Dsquame(R) samplers: technical and physiological validation

An image analysis-based technique for evaluating skin scaliness using Dsquame(R) instant testers is presented, with four surface texture parameters characterizing this condition. Studies on the variability of the technique were carried out to determine the influence of instrumental and physiological factors. Parameters of texture, optical density, number and surface area of squames are calculated from images of obliquely lit Dsquame(R) samples. Repeated measurements were done on artificial and real samples to determine instrumental and sample variability, respectively. In addition, the technique was used in a volunteer study to assess anatomical differences and seasonal variation. For five consecutive measurement days, the artificial samples remained stable, with coefficients of variation for repeatability and reproducibility of less than 8% for all parameters. During the same period, the real samples showed decreases mainly in those parameters of texture and optical density. In the volunteer study, the calf showed significantly higher values (more scaly) in December than July, with no seasonal change in forearm or crow's foot area sites. Assessments of Dsquame(R) instant tester samples using image analysis-derived parameters provides information on the quantity and quality of skin scaliness or flakiness. As such, it is a useful tool for studying desquamation. The technique presented is repeatable and reproducible; however, samples need to be analysed the same day to avoid deterioration problems. Anatomical differences have been demonstrated, with, in addition, the calf showing marked winter/summer changes in comparison to the face and forearm.     

计及焊层疲劳影响的风电变流器IGBT模块热分析及改进热网络模型

针对不同疲劳寿命时期对风电变流器绝缘栅双极型晶闸管(IGBT)模块结温的影响,分析焊层在不同脱落度下的IGBT模块热阻变化规律,并建立考虑热阻变化的改进热网络模型。首先,依据风电机组变流器IGBT模块的结构和材料属性,建立三维有限元热-结构耦合分析模型,对基板焊层和芯片焊层在不同脱落度下IGBT模块结温和热应力的分布规律进行仿真分析。其次,确定不同焊层脱落度下其热阻增量值,并建立IGBT模块改进热网络模型。最后,将三维有限元模型和改进热网络模型的结温计算结果进行对比分析,验证了所提的改进热网络模型的有效性。     

CeO2在铜基胎体金刚石锯片中的应用

本文研究了CeO2在Cu基胎体金刚石锯片中与Al、Mg作用的机理.热力学计算和X-射线衍射分析表明,烧结条件下,胎体中的Al、Mg与CeO2发生反应:3CeO2 4Al→2Al2O3 3[Ce],CeO2 2Mg→2MgO [Ce],生成活性[Ce]、Al2O3和MgO.活性[Ce]降低金刚石与胎体间的界面能,实现胎体材料对金刚石的牢固粘结.在Cu-Al胎体和Cu-Mg胎体中,CeO2的最佳添加量分别为:0.4%和0.6%.切割石材试验表明:CeO2的加入,可以提高金刚石锯片的切割速度,降低脱落度;但切割寿命略有下降.     

CO2中氢渗透阻挡层脱落分析

用电镀Cr-C的方法在氢化锆表面建立的氢渗透阻挡层,在1atm的CO2气氛中和700℃下保温72小时,阻挡层局部发生脱皮和剥落,用SEM对其表面进行观察。观察分析结果表明膜层脱落的原因是预存的物理缺陷以及碳化所致。     

The epidermal engine: a commentary on epidermopoiesis, desquamation and their interrelationships

The physiology and methods for study of epidermal cell production are reviewed. The importance of desquamation to any consideration of epidermal cell population size is stressed. Techniques for the measurement of the rate of desquamation are described with particular emphasis on quantitative dansyl chloride clearance time methods. Although the rates of cell production and cell loss must be related, the possibility of aberrations from a strict equivalence are discussed. Finally, the questions of the control of epidermopoiesis and the changes that occur with ageing are discussed.
La fonction épidermique