442 research outputs found

    借鉴国际经验完善我国资产评估管理体制

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    我国的资产评估业是随着市场经济的发育和成熟逐渐成长起来的,现已成为社会主义市场经济不可或缺的中介服务行业。由于资产评估机构起步较晚,在法制建设、行业统一管理、科研教育等方面还存在着很多问题。本文将通过对国际评估业管理体制的现状及发展趋势的介绍及分析,构建中国资产评估业的新型管理体制

    EFFECTS OF TACHYPLESIN AND N-SODIUM BUTYRATE ON THE MORPHOLOGY AND ULTRASTRUCTURE CHANGES OF HUMAN GASTRIC ADENOCARCINOMA CELLS LINE BGC-823

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    目的以正丁酸钠为平行对照,比较观察鲎素和癌细胞诱导分化物对人胃癌细胞形态与超微结构变化的影响。方法采用光镜、扫描电镜与透射电镜,观察经2.0 mg/L鲎素、2.0 mmol/L正丁酸钠和1.0 mg/L鲎素+1.0 mmol/L正丁酸钠组合处理的人胃腺癌BGC-823细胞。结果光镜观察显示,鲎素和正丁酸钠以及鲎素+正丁酸钠处理的BGC-823细胞形态均较为一致,细胞体积增大、趋于扁平铺展状态,细胞核质比例减小,细胞核形状较圆整,核仁数量减少。扫描与透射电镜观察可见经鲎素、正丁酸钠及其组合处理的BGC-823细胞均出现细胞表面微绒毛稀少,细胞边缘丝状伪足减少,片状伪足增多;细胞核形态较规则,核内异染色质减少,常染色质增多:细胞质内线粒体增多,结构较为一致,高尔基复合体呈较为典型发达状态,并出现粗面内质网增多和多聚核糖体减少等变化。结论鲎素具有与正丁酸钠等诱导分化物相似的改变人胃癌细胞形态与超微结构恶性表型特征的作用,和与诱导分化物协同加成的诱导分化效果。Objective To compare the morphology and ultrastructure changes of human gastric adenocarcinoma cell line treated by tachyplesin and n-sodium butyrate. Methods Light microscope,scanning electron microscope and transmission electron microscope were used to observe human gastric adenocarcinoma cell line BGC-823 treated by 2.0?mg/L tachyplesin,2.0?mmol/L n-sodium butyrate and 1.0?mg/L tachyplesin in combination with 1.0?mmol/L n-sodium butyrate respectively. Results Light microscope observation showed that BGC-823 cells treated by tachyplesin,n-sodium butyrate and tachyplesin+n-sodium butyrate possessed the similar cell modality as follow: the volume of cell increased,the shape of cell became flat and outspread,nucleo-cytoplasmic ratio decreased,the shape of nucleus was rounde,the number of nucleolus decreased.Scanning electron microscope and transmission electron microscope observation showed that,in the BGC-823 cells which were treated with tachyplesin,n-sodium butyrate and tachyplesin in combination with n-sodium butyrate respectively,microvilli and filopodia reduced,sheed pseudopodia increased,the shape of nucleus became regular,heterochromatin decreased while euchromatin increased,the number of mitochondria increased and its structure appeared consistent,Golgi complex turned to be typical,the amount of rough endoplasmic reticulum increased and that of polyribosome decreased.Conclusion All of these results showed that tachyplesin possessed the similar effects to n-sodium butyrate on changing morphology and ultrastructure of human gastric adenocarcinoma cells and possessed an additive role of inducing tumor cells to differentiate cooperatively with n-sodium butyrate to induce carcinoma cell differentiation.国家自然科学基金资助[30170724

    伺服运动控制器的调试方法研究

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    数控机床各进给轴伺服驱动器的参数设置是机床整机调试的一项重要工作。合理的参数设置,是保证机床的加工精度、运行平稳性等基本性能的关键因素之一。通过具体的实践总结,介绍伺服驱动器相关参数设置的基本原则、方法和过程,为数控机床厂商及用户的设备调试与维护提供良好的借鉴

    肉桂酸对人骨肉瘤MG-63细胞增殖和分化的影响

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    目的研究中药有效成分肉桂酸对人骨肉瘤MG-63细胞增殖和分化的影响。方法肉桂酸处理MG-63细胞前后,台盼蓝拒染法进行活细胞计数;流式细胞仪检测细胞周期时相变化;光镜和电镜观察细胞形态和超微结构;VanGieson染色检测细胞Ⅰ型胶原表达;茜素红染色观察钙化骨结节形成;免疫细胞化学检测骨粘素和骨钙蛋白表达。结果肉桂酸明显抑制MG-63细胞增殖,D7抑制率达54.94%±4.69%。周期分析结果显示,肉桂酸处理后G0/G1期细胞比例较对照组明显升高(P<0.01)。光镜和电镜结果显示,肉桂酸处理组MG-63细胞形态和超微结构发生明显改变,呈现相应正常细胞的形态和超微结构特征。肉桂酸促进成骨细胞分化标志物Ⅰ型胶原、骨粘素和骨钙蛋白的表达与钙沉积以及典型骨结节的形成。结论肉桂酸可抑制人骨肉瘤MG-63细胞增殖并诱导其向成骨细胞分化

    学校常勤教員を目指す現職ALTの専門性向上を支える実践事例 ~連合教職大学院ミドルリーダーコースの ALT 院生の学びに寄り添って~

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    松本駅前商業空間における商業機能の変容 : 公園通りを事例に

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    Fish species composition and community pattern in the continental shelf of northwestern South China Sea

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    根据2006—2007年在南海西北部陆架区海域进行的4航次底拖网调查数据,对该海域鱼类的种类组成和群落格局进行分析。调查共采获鱼类262种,隶属于20目102科。以冬季出现种类数最多,为166种;夏季和秋季次之,分别为161种和155种;春季最少,为135种。运用聚类分析和非度量多维标度(nMdS)方法分析了南海西北部陆架区鱼类群落结构的空间分布。研究表明,该海域鱼类可划分为5个群落,分别为粤西沿岸群落(群落Ⅰ)、海南岛东南沿岸群落(群落Ⅱ)、海南岛东部深海群落(群落Ⅲ)、过渡群落(群落Ⅳ)和混合群落(群落V)。AnOSIM检验表明,各群落间鱼类组成的差异极为显著(r=0.847-0.939,P<0.001)。鱼类群落格局的变化与海流和水深关系密切,有较明显的沿水深梯度分布的规律。咸淡水鱼类在雷州半岛东部的冷涡区域,形成群落Ⅰ;南海暖流控制区域内的深海鱼类,形成群落Ⅲ;在南海暖流最为强劲的冬季,研究区域内大部分鱼类集结为混合性群落V;琼东南沿岸的上升流区内形成群落Ⅱ;沿岸流强劲的夏、秋季,在沿岸流和上升流交汇处,形成过渡性群落Ⅳ。To understand fish species composition,community pattern,dominant species and seasonal variation in the continental shelf of northwestern South China Sea,four otter trawl surveys were conducted in January and August 2006,and April and November 2007,representing winter,summer,spring and autumn,respectively.Sixteen stations were assigned in each otter trawl survey along the coastlines from eastern Leizhou Peninsula to southeastern Hainan Island.Fish collection and data analysis followed the National Marine Survey Standards(GB/T12763.6—2007).Totally 262 fish species,from 102 families and 20 orders,were collected in the four seasonal surveys.The results revealed that the highest species diversity was in winter with 166 species recorded and the lowest was in spring with 135 species recorded;161 and 155 species were recorded in summer and autumn,respectively.The Order Perciformes was the most important fish group in the continental shelf of northwestern South China Sea;the highest species diversity recorded was the Perciformes in all four seasons,and 40 out of 72 species recorded year-round belonged to the Perciformes.Species found in all four seasons contributed to 80.34% of total fish biomass.Ninety-one species found only in a single season contributed to 1.62% of total fish biomass.The spatial pattern of fish communities was analyzed using the hierarchical clustering and non-metric multi-dimensional scaling(NMDS),five fish groups were indentified.The Group Ⅰ,recorded in all four seasons,was located in the coastal waters of western Guangdong Province and consisted of 3 or 4 stations.The scale and the distribution area of the Group Ⅰ were stable among seasons.The Group Ⅱ,recorded in spring,summer and autumn,was located in the coastal waters of southeastern Hainan Island and consisted of 6—9 stations.The scale and the distribution area of the Group Ⅱ had seasonal variation.The Group Ⅲ,recorded in spring,summer and autumn,was located in the deep waters of eastern Hainan Island and consisted of 4 stations.The scale and the distribution area of the Group Ⅲ were stable.The Group Ⅳ as a transitional community,recorded in summer and autumn only,was located in the deep waters of eastern Hainan Island and consisted of 1—3 stations.The scale and the distribution area of the Group Ⅳ were small and changed largely with season.The Group Ⅴ as a mixed community,recorded in winter only,was also located in the deep waters of eastern Hainan Island and consisted of 13 stations.The scale and the distribution area of the Group Ⅴ were the largest among the 5 groups.Based on the analysis of similarities(ANOSIM),the results showed the significant differences(R=0.847-0.939,P <0.001) in fish community pattern for all four seasons.Although the station combinations in each fish community had seasonal variation,the correlation coefficients on the community similarities between spring and summer,between summer and autumn and between autumn and winter were 0.780,0.630 and 0.777,respectively.The variations of fish community pattern are closely related to ocean currents and depth.The brackish fishes distributed in the cold eddy area of eastern Leizhou Peninsula and contributed to the Group Ⅰ.The deep sea fishes along the South China Sea Warm Current in eastern Hainan Island contributed to the Group Ⅲ.In winter with the strongest South China Sea Warm Current recorded in the deep waters of eastern Hainan Island,the area was dominated by fishes from the mixed Group Ⅴ.Because of the upwelling in the coastal waters of southeastern Hainan Island the area was dominated by fishes from the Group Ⅱ.In summer and autumn,the coastal current was strong and mixed with the upwelling in the deep waters of eastern Hainan Island;therefore,the area was dominated by fishes from the transitional Group Ⅳ.This study provides scientific evidences for further sustainable fisheries development and conservation in the continental shelf of northwestern South China Sea.我国近海海洋综合调查与评价专项(908-01-ST08); 中央级公益性科研院所基本科研业务费专项资金(中国水产科学研究院南海水产研究所)资助项目(2009TS08;2010YD01和2010YD10); 农业部近海渔业资源调查项目(070404); 海洋公益性行业科研专项(201005012); 广东省海洋渔业资源综合评价资助项目(GD908-02-05

    考虑绳阻尼的绳系并联机器人动力学特性分析

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    针对应用于风洞试验模型支撑的绳系并联机器人的设计需求,采用实验和理论建模相结合的方法,研究绳阻尼对绳系并联机器人动力学特性的影响。首先,为了准确地定量描述绳阻尼,设计了一套测量绳索阻尼的实验装置,通过实验得到了不同参数下的绳阻尼比;其次,考虑了绳阻尼,对绳张力进行建模,并提出了考虑绳阻尼的绳系并联机器人的动力学建模方法;最后,分析了绳阻尼对绳系并联机器人动力学特性的影响。结果表明:绳阻尼对绳系并联机器人动力学响应的影响主要体现在响应幅值上,绳直径越大,绳阻尼对绳系并联机器人动力学响应的减振作用越明显。当绳阻尼系数大于0.6 N·s/m时,不论绳直径粗细如何,绳阻尼对绳系并联机器人动力学特性的影响不能忽略。国家自然科学基金(基金号11472234,11702232,11072207);;\n中央高校基本科研业务费(20720180071

    低速风洞飞行器模型编队飞行绳系并联支撑机构研究

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    本文设计了一种用于飞行器双机编队飞行的风洞试验模型绳系并联支撑机构,模拟在周边有障碍物的有限空间通道中的飞行运动。文中以直升机为例,根据工况参数设计了双绳牵引并联机构作为飞行器模型的支撑,建立了基于可移动的滑轮铰点与直升机模型编队协同飞行的运动学模型,对系统的静刚度进行了分析,并通过实验验证了旋翼转动对该绳系支撑系统动刚度的影响,给出了在有限空间通道中模拟双机编队飞行与着陆过程中绳与绳之间、绳与模型之间的干涉算法,并对该支撑机构的绳系结构进行了干涉分析。分析结果表明,本文设计的支撑机构能有效解决模拟飞行器模型双机编队在有限空间中飞行运动时的支撑干涉问题,而且系统刚度达到低速风洞试验的稳定性要求,是低速风洞中支撑飞行器模型进行编队飞行试验的有效解决方案。国家自然科学基金(11472234,11702232);;\n中央高校基本科研业务费(20720180071
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