桶装水外洗机的优化设计及应用

针对现有桶装水外洗机清洗速度慢、清洗质量难以保证,进桶时容易倒桶、卡桶的缺陷,提出了针对5加仑水桶外洗机的优化设计方案。整机包括:驱动装置、传动装置、洗桶装置、拨桶装置等几大系统;采用Solidworks三维建模,确保了设计的可行性。     

液压控制带压作业试验台研制

研制的液压控制带压作业试验系统由液压起升装置、井口防喷密封装置、管枉接箍探测装置、压力平衡装置、高压流体循环系统、液压动力系统和实验台基础装置组成；采用S7-200型PLC作为液压控制系统的控制器，可以实现模拟带压作业工艺流程试验的自动控制。     

船体清洗装置的国内外应用与现状分析

目前,国内船体表面的清洗作业均是在船坞内进行,能够成功用于水下作业的自动化清洗设备仍需要潜水员下水进行作业,成本高而且工作效率低下。本文介绍了国内外有关船体清洗的现状及各种设备的优缺点及相关技术,如坞内清洗技术、水下清洗技术等,对今后船体水下清洗装置发展动态进行了分析,为船体清洁装置的发展提供了理论依据。     

无氰滚镀锌的优选

一、优选内容:优选烧碱和电流、达到无氰滚镀锌的目的。原配方:烧碱100—180克/升氧化锌15—20克/升DE 添加剂4毫克/升TE 添加剂1毫克/升电流200安/桶(约15公斤)优选后烧碱149.44克/升,电流161.8安/桶。二、试验过程:     

基于道路照明灯罩机械臂式末端清洗系统研究

为了实现路灯灯罩表面自动化清洗作业,设计了一种搭载于高空作业平台的机械臂式末端清洗装置。对末端清洗装置建模,并进行运动学求解论证了刷盘与灯罩间位置关系,采用MATLAB/Simulink仿真软件验证了臂架角度调节和压力控制的有效性。结果表明:机械臂式末端清洗装置可以实现刷盘与灯罩表面对准且保持稳定的刷盘与灯罩间压力,并实现自动化清洗功能。为路灯清洗装置自动化作业提供了理论依据。     

微型道路养护车清洗装置的设计

为实现城市窄路面道路机械化清洗作业,自行研发了一种微型道路养护车清洗装置。文章论述了其功能原理设计、结构设计计算、外观设计和设计校核等。该清洗装置清洗效率高,清洗范围理想,而且制作简单,安装方便,成本低,利于推广。     

壁面自动清洗机器人清洗工艺分析

本文结合壁面自动清洗机器人样机的研制,对清洗作业中的关键技术-清洗机构选型、喷淋系统、接水刮水装置、污水处理、清洗恒压装置等进行了研究,通过清洗样机的清洗实验和测试,对壁面清洗原理及壁面清洗工艺进行了分析,对以后进一步的研究进行了有益的探索。     

核电起重机起升故障动态特性研究

根据核电起重机起升机构的特殊构造,建立了核电起重机在吊重离地起升发生断绳故障时机构与桥架结构耦合的弹性多体动力学模型。考虑到2套独立构造、同步驱动吊钩升降的起升卷绕系统的均衡杠杆两端,正常设置受压缓冲装置或假设去掉缓冲装置这2种情况,用Matlab\Simulink工具箱对1根钢丝绳突然断开的故障状态进行仿真对比,验证了核电起重机起升机构设置缓冲减振装置的优越性,其使作业突发故障时机构和主梁结构的振动得到减缓和控制,提高了核电起重机的故障作业安全性。     

油罐清洗机器人自激脉冲装置的动力学仿真

油罐清洗机器人是机械化清灌的重要而有效的工具,自激脉冲装置是清洗机器人的一种机械手臂式喷射清洗装置。基于虚拟样机技术,首先利用SolidWorks软件完成了油罐清洗机器人自激脉冲装置的三维实体建模;然后利用SolidWorks自带功能插件对该装置进行了干涉检查,验证了零部件装配设计的合理性,并进行了0°角和120°角极限工作位置的有限元受力分析,验证了设计选材和工作过程的可靠性;最后将三维实体模型导入ADAMS中,建立了动力学仿真模型,进行了三维可视化动力学仿真分析,获得了其运动学和动力学特性,验证了装置作业过程的稳定性。     

基于磁隙式吸附机构的槽车清洗机器人

给出了一种基于磁隙式吸附机构的槽车清洗机器人机构设计方案,采用磁隙式吸附装置平衡清洗作业过程中高压水枪反向冲击力产生的倾覆扭矩,提高系统稳定性裕度。建立数学模型描述清洗作业力学行为,利用有限元仿真优化磁吸附模块设计参数,计算不同气隙高度下单个磁吸附装置产生的吸附力。根据仿真结果,当采用2块40 mm×40 mm×15 mm与2块80 mm×40 mm×15 mm的永磁铁,磁铁间隙为10 mm,轭铁厚度为9 mm,气隙高度为10 mm时,单个磁吸附装置能够产生693 N的吸附力,槽车清洗机器人能够在20 MPa的清洗水压下稳定地工作。     

Histochemical and ultrahistochemical localization of heavy metals in calf organs

Cadmium, zinc, selenium, and copper were administered, singly or in combination, orally or subcutaneously. Experiment I included 32 calves of both sexes; six received Cd (two groups), Zn, Cd, and Zn, and Cd and Se (two groups) and one group was a control. In Experiment II (21 bulls), three were given Cd, Cd, and Cu, and Cd and Zn, respectively, and one group was a control. For light microscopy, in Experiment I the highest amounts of silver granules were present in the samples of liver, small intestine, and vesicular gland of all the exposed groups; in Experiment II the most affected organs were liver, kidney, and small intestine. For electron microscopy, in Experiment I, after administration of Cd and Zn, the highest amounts of granules were seen in the cytoplasm of hepatocytes and cells of the proximal and distal renal tubules and the lowest amounts were found in glandular cells of the pancreas. Administration of Cd and Se resulted in the presence of large numbers of granules in the nuclei and nucleoli of spermatogonies. In Experiment II, ingestion of Cd and Zn in feed led to the appearance of highest amounts of granules in the nucleoli, nuclei, and cytoplasm of cells in testes, kidneys, and pancreas. Following Cd intake, the highest accumulation of granules was observed in the nucleoli of hepatocytes and cells of the proximal and distal renal tubules. Combined Cd and Cu produced the highest number of granules in cells of the proximal and distal renal tubules and in the nucleoli and nuclei of germinal epithelium.     

Mechanotransduction-The relationship between gravity,cells and tensile loading in extracellular matrix

Gravity plays a central role in vertebrate development and evolution. Mechanotransduction involves the tensile tethering of veins and arteries, connections between the epidermis and dermis in skin, tensile stress concentrations that occur at tissue interfaces, cell-cell interactions, cell-collagen fiber stress transfer in extracellular matrix and fluid shear flow. While attention in the past has been directed at understanding the myriad of biochemical players associated with mechanotransduction pathways, less attention has been focused on determining the tensile mechanical behavior of tissues in vivo. Fibroblasts sit on the surface of collagen fibers in living skin and exert a retractile force on the fibers. This retractile force pulls against the tension in collagen fibers in skin. After fibroblast-collagen fiber interactions are altered either by changes in fibroblast adhesion or after formation of cancer associated fibroblasts, and changes in cell junctions, alterations in the retractive force leads to changes in mechanotransduction. The purpose of this paper is to present a model of tensile forces that occur at the fibroblast-collagen fiber interface and how these forces are important in extracellular matrix physiology in health and disease.     

The intracellular distribution of ions and water in rat liver and heart muscle

Local dry mass concentrations of intracellular compartments in rat heart muscle and liver cells were estimated by quantitative electron microscopy and X-ray microanalysis of ultrathin frozen-dried cryosections. The results were used to calculate elemental concentrations per litre of compartment water from the X-ray microanalytical data. Water fractions were between 80.3 ± 1.3% of wet weight in the decondensed chromatin and only 45.1 ± 1.7% in mitochondria of liver cells. The lowest water fraction in heart muscle cells was also found in mitochondria. The ionic concentrations found in the cytoplasm of liver cells and in the myofibrils are in accord with the electroneutrality rule and in osmotic equilibrium with the extracellular concentrations. The concentrations of Na, K, Cl and P both in the cytoplasm and in the regions of decondensed chromatin within the nuclei were found to be equal. However, in regions of condensed chromatin K⁺ concentrations were found to be much higher than expected for a Donnan distribution of ions free in solution. Most probably the activity coefficient for K⁺ is lower in the condensed chromatin than in the decondensed or in the cytoplasm. The same holds true for the A-band as compared to the I-band in heart muscle cells. A sequestration of K⁺ was measured also in the rough endoplasmic reticulum (RER) of hepatocytes. The Cl^? concentration in mitochondria both in heart muscle and liver cells has been measured far in excess of what might be expected from a Nernstian distribution. A coupled inward Cl^? transport in mitochondria must, therefore, be assumed.     

Ciliary neurotrophic factor increases the survival of magnocellular vasopressin and oxytocin neurons in rat supraoptic nucleus in organotypic cultures.

Organotypic cultures of the rat hypothalamus are very useful models for the long-term study of parvocellular vasopressin (VP) neurons in the paraventricular (PVN) and suprachiasmatic (SCN) nuclei. However, they do not preserve significant numbers of VP magnocellular neurons (VP-MCNs) in either the PVN or the supraoptic nucleus (SON). Vutskits et al. [(1998) Neuroscience 87:571-582] reported that ciliary neurotrophic factor (CNTF) was a selective survival factor for rat VP-MCNs in organotypic cultures of the rat hypothalamic paraventricular nucleus (PVN). We examined the effects of CNTF on the survival of these neurons in rat and mouse SONs. CNTF (10 ng/ml) in the culture media increased the survival of VP-MCNs by 6-fold and OT-MCNs by 3-fold. In the mouse, both OT- and VP-MCNs survive very well in organotypic cultures under standard culture conditions and the addition of CNTF had no further effect. Consistent with these results, in situ hybridization showed substantially higher levels of VP- and OT-mRNA in rat PVNs and SONs in the presence of CNTF, but produced no changes in these nuclei in the mouse. The optimum period for the survival effect of CNTF on MCNs in the rat hypothalamic cultures was in the first 7-10 days of culture and this effect is maintained for at least 5 additional days if CNTF is then removed from the medium. Therefore, using CNTF in the culture media can provide an opportunity for long-term studies of rat VP- and OT-MCNs in SONs in organotypic cultures.     

Gender-related changes in the avian vasotocin system during ontogeny

The arginine vasotocin (AVT) system of the avian brain includes a sexually dimorphic part that extends from the caudal part of preoptic region through the medial part of the bed nucleus of stria terminalis (BSTm) to the lateral septum. It is composed of the parvocellular neurons located in the BSTm and the dense innervation of the medial preoptic region and lateral septum. In this part of the brain, AVT expression is stronger in males than in females in a few bird species investigated to date. This review focuses on the ontogeny of sexual differences in the vasotocinergic system of two gallinaceous species, domestic chicken and Japanese quail, and on the role of gonadal hormones in organizing during development and maintaining in adulthood these differences. Parvocellular AVT neurons become discernible in the BSTm of males and females during the second half of embryonic development. These cells undergo a profound and irreversible sexual differentiation during ontogenetic development. Recent findings demonstrate a dual role of estrogens in the organization and activation of sex differences in the AVT system. During the embryonic period of ontogeny, estrogens differentiate the AVT system in a sexually dimorphic manner in parallel with the differentiation of sexual behavior, while in adulthood estrogens, locally produced from testosterone in the male brain, activate AVT synthesis in the BSTm. The sexually dimorphic part of the AVT system is sensitive to a number of abiotic factors such as light, temperature, and water availability. It is suggested that sex dimorphic vasotocinergic systems could be implicated in processes of social recognition in various behavioral contexts.     

轮轨关系研究中的力学问题

简单论述世界铁路发展状况和铁路交通运输的优越性。详细论述轮轨关系的研究问题,其研究包含轮轨滚动接触作用和稳定性问题、轮轨粘着和强度、接触表面磨损和滚动接触疲劳破坏、轮轨噪声、轮轨蠕滑率／力理论和轮轨三维弹塑性滚动接触问题。在这些问题研究中,蕴涵十分复杂的力学和强度问题。文中就这方面的研究现状和存在问题以及问题研究的难点进行讨论,并分析今后可能的研究方向。     

五自由度机器人的结构设计及其控制

介绍了串联五自由度机器人的机械结构和机器人控制系统的设计.文中设计的五自由度机器人既可以用于实际生产,也可以用于教学和科研.用于实际生产既可以执行点位控制下的操作,也可以执行连续轨迹控制下的操作;用于教学和科研时,该机器人可用于机器人结构分析、机构运动学分析及机器人控制系统的教学演示和实验操作.它具有结构简单、操控方便等特点,而且可以做进一步的研发.     

Sex differences in songbirds 25 years later: What have we learned and where do we go?

About 25 years ago, Nottebohm and Arnold reported that there are profound male-biased sex differences in volume in selected nuclei in telencephalic portions of the song control system. This review focuses on issues related to the cellular bases of these sex differences in volume and comparative studies that might elucidate the function of this variation between the sexes. Studies utilizing a variety of neurohistological methods in several different species to define the boundaries of two key telencephalic song nuclei HVc and the robust nucleus of the archistriatum (RA) all tend to find a sex difference in volume in agreement with Nissl-defined boundaries. Sex differences in volume in nuclei such as HVc and RA are associated with differences in cell size and cell number. Other attributes of the phenotype of cells in these nuclei are also different in males and females such as the number of cells expressing androgen receptors. Comparative studies have been employed to understand the function of these sex differences in the brain. In some songbird species, females sing rarely or not at all, and the brain nuclei that control song are many times larger volume in males than females. In other species, males and females sing approximately equally, and the brain nuclei that control song are approximately equal between the sexes. Recently, statistical methods have been employed to control for phylogenetic effects while comparing the co-evolution of traits. This analysis indicates that the evolution of sex differences in song has co-evolved with the evolution of sex differences in singing behavior in songbird species. Future studies should focus on the function of the smaller song control nuclei of females and investigate the role these nuclei might play in perception as well as in production. Microsc. Res. Tech. 54:327–334, 2001. © 2001 Wiley-Liss, Inc.     

Distribution of sex steroid hormone receptors in the avian brain: functional implications for neural sex differences and sexual behaviors

Developmental and seasonal changes in the production of androgens, estrogens, and progestins seem to control sex-specific differentiation and seasonal changes in appetitive and consummatory sexual behaviors of birds. This results in profound sex differences in the quality (sex-specific) or quantity (sex-typical) of behaviors such as courtship, territoriality, or copulation. Steroids affect the brain by binding to intracellularly located receptors. The same brain areas express androgen, estrogen, and progesterone receptors in male and female brains. Sex differences in these genetically determined patterns occur in the size of neuron populations that intrinsically express sex steroid receptors. Further permanent sex differences are subsequent to degenerative fates of receptor expressing neuron populations during ontogeny. Transient sex differences in receptor expression appear to be due to area-specific up- and down-regulation of receptor levels, reflecting transient changes in the level of circulating steroids, changes in environmental conditions, or in the physiological status of the individuals. In particular, intrinsic sex differences in the expression pattern of sex steroid receptors and steroid-independent regulation of the expression level of these receptors in the brain are limiting mechanisms for gonad-dependent sexual development and activities.     

Use of primary cell cultures and intact isolated glandular epithelia for X-ray microanalysis

Changes in the elemental composition of cells during isolation of glandular epithelia were studied by electron probe X-ray microanalysis. Fine chopping of rat submandibular gland followed by enzymatic treatment for 15 min caused marked increases in Na and Cl and a decrease in K concentrations in acinar cells. After enzymatic treatment for 50 min, Na, Cl and K concentrations returned to close to the control level. Mechanical disaggregation of the acinar clumps following enzymatic treatment resulted again in minor increases in Na and Cl and a marked decrease in K concentration. Exposure of isolated acini to cholinergic stimulation in vitro resulted in secretion of Cl and K from the acinar cells. Dissection of the sweat gland from human skin caused a decrease in the K/Na ratio. Incubation of the gland for 30–45 min with collagenase gave rise to a gradual decrease in the K/Na ratio. After mechanical separation of the gland into the secretory coil and reabsorptive duct, a further reduction of the K/Na ratio was seen. However, the duct cells had a much lower K/Na ratio and higher Ca concentration than the coil cells. In primary cultures, the K/Na ratios of the coil and duct cells returned to the in situ level. The elemental composition of sweat gland cells incubated in collagenase-containing medium was no different from that in cells incubated in collagenase-free medium. In the intact collagenase-isolated tissue, Cl^? secretion in the coil was elicited by carbachol but not by cAMP, whereas in the duct cells the reverse was the case. In primary cell cultures, Cl^? efflux in both coil and duct cells could be elicited by both carbachol and cAMP. In conclusion, although changes in elemental composition of gland cells during the isolation procedure occur, physiological responses can be detected. When primary cell cultures are used, it should be borne in mind that cultured cells may have physiological properties different from those of the intact tissue.