新型电磁振动式标准筛振筛机的研制

介绍了一种新型电磁振动式Φ２００ｍｍ标准筛振筛机的结构、工作原理。该机利用电磁振动和弹簧片振动的联合振动作用,使固定筛子的框架和筛子同时振动。与机械运动式的ＸＳＢ－７０Ｂ型Φ２００ｍｍ标准筛振筛机相比,具有振击频率高、能在较短时间内达到筛分终点、结构简单、重量轻、造价低,使用时噪音小和方便等优点。     

Active beam vibration control using PZT actuators

Abstract

Smart materials of lead-zirconate-titanate (PZT) piezoelectric ceramics have attracted attention in recent years for active vibration control, acoustic noise suppression, health monitoring and damage assessment. We at McDonnell Douglas Aerospace have been studying these ceramics for use as sensors and actuators in various space and aircraft structures. In this paper, we will report results of a recent study on active vibration control using monomorph PZT actuators. The experiments were performed on thin aluminum cantilever beams. Collocated and non-collocated sensors and actuators were employed. Two control techniques: the classical velocity feedback and adaptive feedback controls, were investigated. We have obtained significant damping and broadband vibration attenuation of greater than 30 dB using the classical control with the single-input single-output feedback approach. A 24 dB reduction has also been achieved using the adaptive control with the multiple-input single-output approach. Detailed experimental methods and results will be described.     

济宁路和汉口路山羊皮组织构造对比的研究

本文论述了采用组织显微切片技术对比研究了济宁路和汉口路山羊皮组织构造特点及特征。研究结果表明,济宁路山羊皮张幅小,皮板薄,部位厚度差稍大些;汉口路山羊皮张幅大,皮板厚,部位厚度差稍小些。济宁路山羊皮毛密,绒毛多,皮内毛根底部毛球有的呈钩形;汉口路山羊皮毛稀些,绒毛少些,毛球不弯曲。济宁路山羊皮各部位表皮厚度都比汉口路山羊皮薄,但乳头层厚度,济宁路比汉口路山羊皮厚些,济宁路山羊皮乳头层乳头部凸起较明显,沟纹较深,而汉口路山羊皮乳头层较平垣,沟纹较浅。济宁路和汉口路山羊皮的乳头层上、中部分,胶原纤维细,上部比中部还细,编织紧密;下部分,胶原纤维含量较少,编织疏松,至针毛毛球底部处胶原纤维虽粗些,但编织亦十分疏松。网状层内,胶原纤维粗些,上部分编织疏松,下部分编织紧密些。汗腺、弹性纤维、竖毛肌,济宁路比汉口路山羊皮发达;皮脂腺,汉口路比济宁路山羊皮发达。     

浅析尿素振动筛的改造

针对尿素振动筛振动大,严重影响设备及基础结构的安全使用等问题,分析其原因,并制定相应的改造措施。改造后,产品质量大幅度提升,振动大大降低,保证了设备及基础结构的安全、稳定、长周期运行。     

Effects of Electromagnetic Waves with LTE and 5G Bandwidth on the Skin Pigmentation In Vitro

With the rapid growth of wireless communication devices, the influences of electromagnetic fields (EMF) on human health are gathering increasing attention. Since the skin is the largest organ of the body and is located at the outermost layer, it is considered a major target for the health effects of EMF. Skin pigmentation represents one of the most frequent symptoms caused by various non-ionizing radiations, including ultraviolet radiation, blue light, infrared, and extremely low frequency (ELF). Here, we investigated the effects of EMFs with long-term evolution (LTE, 1.762 GHz) and 5G (28 GHz) bandwidth on skin pigmentation in vitro. Murine and Human melanoma cells (B16F10 and MNT-1) were exposed to either LTE or 5G for 4 h per day, which is considered the upper bound of average smartphone use time. It was shown that neither LTE nor 5G exposure induced significant effects on cell viability or pigmentation. The dendrites of MNT-1 were neither lengthened nor regressed after EMF exposure. Skin pigmentation effects of EMFs were further examined in the human keratinocyte cell line (MNT-1-HaCaT) co-culture system, which confirmed the absence of significant hyper-pigmentation effects of LTE and 5G EMFs. Lastly, MelanoDerm™, a 3D pigmented human epidermis model, was irradiated with LTE (1.762 GHz) or 5G (28 GHz), and image analysis and special staining were performed. No changes in the brightness of MelanoDerm™ tissues were observed in LTE- or 5G-exposed tissues, except for only minimal changes in the size of melanocytes. Collectively, these results imply that exposure to LTE and 5G EMFs may not affect melanin synthesis or skin pigmentation under normal smartphone use condition.     

Mitotic Diversity in Homeostatic Human Interfollicular Epidermis

Despite decades of skin research, regulation of proliferation and homeostasis in human epidermis is still insufficiently understood. To address the role of mitoses in tissue regulation, we utilized human long-term skin equivalents and systematically assessed mitoses during early epidermal development and long-term epidermal regeneration. We now demonstrate four different orientations: (1) horizontal, i.e., parallel to the basement membrane (BM) and suggestive of symmetric divisions; (2) oblique with an angle of 45°–70°; or (3) perpendicular, suggestive of asymmetric division. In addition, we demonstrate a fourth substantial fraction of suprabasal mitoses, many of which are committed to differentiation (Keratin K10-positive). As verified also for normal human skin, this spatial mitotic organization is part of the regulatory program of human epidermal tissue homeostasis. As a potential marker for asymmetric division, we investigated for Numb and found that it was evenly spread in almost all undifferentiated keratinocytes, but indeed asymmetrically distributed in some mitoses and particularly frequent under differentiation-repressing low-calcium conditions. Numb deletion (stable knockdown by CRISPR/Cas9), however, did not affect proliferation, neither in a three-day follow up study by life cell imaging nor during a 14-day culture period, suggesting that Numb is not essential for the general control of keratinocyte division.     

“研究生论坛”稿件--新型水力翻板闸堰孔混合泄流能力研究

采用概化模型试验探讨了新型水力翻板闸门的堰孔混合泄流能力,得到了开度、流量、水位的相关关系,提出了一种计算水力翻板闸堰孔混合泄流能力的新方法——修正系数法。试验成果表明,常用的综合流量系数法有较好的精度,其中,多项式拟合最优,线性拟合其次,指数拟合相对较低;修正系数法较常用的综合流量系数法具有更好的精度及实用性。该研究成果为新型水力翻板闸门的设计及应用可提供一定的参考价值。     

某型飞机襟翼自动检测系统的设计

某型现代战机襟翼伺服控制系统在维护保障上存在检测仪器功能单一、通用性差、检测效率低、可靠性不高等问题,因此研制了该型飞机襟翼自动检测系统。系统以嵌入式工控机为核心,将CPU板、A／I)板、D／A板、I／O板按层叠式结构组合在一起,利用Turboc C 2．0进行编程,运行在UCDOS7．0环境下。该自动检测仪具有测量精度、智能化及自动化程度高,可靠性及通用性好,体积小,重量轻,操作简便等优点。经使用,该设备覆盖了原有设备的全部功能,且技术先进,性能优越,极大提高了部队维修保障效率。     

胃上皮肿瘤边界跟踪算法的实现

提出了一种修正型的边界跟踪算法,该算法基于区域标号算法,并以外法线方向作为优先搜索方向来确定边界点,在边界跟踪过程中不但记录目标物体的边界点,而且还将校正像素点的归属区域。针对该算法,设计了一个2维链表的数据结构用来保存跟踪的边界点。     

Epidermal lipids

From the time an epidermal cell leaves the basal layer to the time it is desquamated, the cell lipids change dramatically, both qualitatively and quantitatively. The most abundant lipid class in basal cells is phospholipid with the remaining lipid being accounted for by roughly equal proportions of cholesterol, non-esterified fatty acid, triacylglycerol and glycolipid: minor components include cholesteryl esters and ceramide. In contrast, approximately half of the lipid in a desquamated cell consists of ceramide, with the remainder consisting largely of cholesterol and non-esterified fatty acid. Immediately before desquamation, small concentrations of cholesteryl sulphate and glycolipid have been found and there is evidence that these polar lipids are important components of the water barrier and also contribute towards the physical integrity of the lower part of the stratum corneum. The change in lipid content as cornification proceeds is no less dramatic than the change in lipid composition. A basal cell contains about 10 pg lipid, whereas a desquamated stratum corneum cell contains approximately six times this amount. The change in lipid composition of a cell undergoing cornification results, therefore, largely from de novo synthesis of lipid, especially cholesterol, non-esterified fatty acid and ceramide.
Les lipides de l'épiderme