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81.
对城市防洪、非工程措施、洪水预报与数值模拟技术的重要性进行阐述,结合浑河沈阳城市段分别从预报方案和预报系统技术对系统的功能结构进行归纳总结。同时,介绍了数值模拟技术在城市防洪中的应用情况,提出具有继承性和发展性自动化系统解决方案。应用该系统妥善解决了浑河防洪减灾中原有存在的疑难问题,为浑河防洪减灾工作提供全面支持。  相似文献   
82.
从技战术实际需要出发,给出了某型飞机作战损毁后机载电缆的智能化诊断系统的硬件结构框图。根据硬件系统模拟开关组件的原理,定义了电缆的连接矩阵、测量矩阵以及断口的映像矩阵运算,给出了断头查找的算法。计算表明,系统可在20 min内完成一个循环的断头查找并给出故障定位。  相似文献   
83.
Previous studies on business simulation games (BSGs) have concluded that improved performance may not be the primary benefit of using BSGs, due to mixed results between student performance and perceptions. Two relevant and insightful issues attract our attention, namely, the impacts of the heterogeneous student population and the different complexity levels of BSG software. To address these issues, the present study aims to understand the relationship between student profile/characteristics and performance in the classroom with BSG-facilitated learning. An in-depth case study is conducted on a general college course designed to teach three different complexities of BSGs to students enrolled in different majors. Four student profile factors are individually tested for differences in performance scores as evaluated by the teacher. Additionally, the influences of 11 student characteristics are assessed with regard their self-reported perceived learning performances. Regression analysis and ANOVA are used to investigate the impacts of heterogeneous users and game complexity on student performance. Based on the regression analyses of the data collected from 43 respondents who participated in the general course, the study concludes that knowledge and skill may influence the heterogeneous student population; moreover, student participation and tacit learning preference improve performance, and students with an auditory learning preference or high learning motivation may not perform well in classroom BSG learning. However, the low value of adjusted R square implies that more dimensions or variables are needed to increase the explaining power of the performance scores in the regression analyses. In contrast, heterogeneous BSG software with different complexity levels present different results. The current research contributes practical and incremental knowledge on the complexity of heterogeneous BSG software on performance scores and the perceived learning performance of heterogeneous student populations. With the research limitations acknowledged, a series of suggestions for teachers pertaining to appropriate applications of BSGs in classes is offered as well as recommendations to BSG providers. Nevertheless, in-depth analyses are required, preferably with larger student population samples, to further explore the insignificant relationship between student perceptions and attitude under nonlinear extended complexity.  相似文献   
84.
This paper presents a novel global localization approach for mobile robots by exploring line-segment features in any structured environment. The main contribution of this paper is an effective data association approach, the Line-segment Relation Matching (LRM) technique, which is based on a generation and exploration of an Interpretation Tree (IT). A new representation of geometric patterns of line-segments is proposed for the first time, which is called as Relation Table. It contains relative geometric positions of every line-segment respect to the others (or itself) in a coordinate-frame independent sense. Based on that, a Relation-Table-constraint is applied to minimize the searching space of IT therefore greatly reducing the processing time of LRM. The Least Square algorithm is further applied to estimate the robot pose using matched line-segment pairs. Then a global localization system can be realized based on our LRM technique integrated with a hypothesis tracking framework which is able to handle pose ambiguity. Sufficient simulations were specially designed and carried out indicating both pluses and minuses of our system compared with former methods. We also presented the practical experiments illustrating that our approach has a high robustness against uncertainties from sensor occlusions and extraneous observation in a highly dynamic environment. Additionally our system was demonstrated to easily deal with initialization and have the ability of quick recovery from a localization failure.  相似文献   
85.
为满足实验室单克隆抗体的制备研究,本实验特对实验室常用的制备单抗的模拟抗原(Ac-NK16-Ahx-3)进行ELISA间接法检测,进而建立一种高效的检测方法。通过对不同稀释度待测抗体的免疫吸附测定,检测出它的最终灵敏度为0.078mg/mL,最佳二抗稀释倍数为300倍,其最佳拟合曲线为y=-0.0732x+0.6875,R2=0.8619。并且,通过统计学方法进行统计分析,确定出各实验组的相关性及变异系数,从而排除实验中的操作误差,最终可确定最佳的实验条件,并保证实验的准确性。  相似文献   
86.
A large number of high-voltage power transmission towers have recently been constructed in mining areas prone to subsidence.In order to ensure the safety of the transmission towers and the safe operati...  相似文献   
87.
目的 探讨单纯疱疹病毒胸苷激酶(HSV-tk)基因/丙氧鸟苷(GCV)系统杀伤肿瘤细胞时旁观者效应与细胞间缝隙连接的关系。方法 用PA317细胞包装STK质粒(逆转录病毒载体介导的HSV-tk基因),形成假逆转录病毒颗粒,转染有缝隙连接的大鼠胶质瘤细胞C6和无缝隙连接的入宫颈癌细胞 Hela,制成 C6 tk+和 Helatk+细胞,将不同比例的C6和 C6 tk+、Hela和 Hela tk+细胞混合,每种比例8孔,培养 24h后 4孔加入含0.5μg/mlGCV的培养基,4孔作对照,6d后用MTT法测量细胞存活率。在两个培养皿中放入周围粘有33mm高滤纸的载玻片,分别接种 C6、C6 tk+细胞。细胞 80%汇合后将载玻片互换,并加入含0.5μg/ml GCV的培养基,6d后观察细胞形态。结果C6细胞组存在旁观者效应,Heal细胞组不存在旁观者效应。培养皿中tk+细胞大部分被杀死,tk-细胞无变化。结论HSV-tk基因/GCV系统杀伤肿瘤细胞时旁观者效应与细胞间缝隙连接有关。  相似文献   
88.
Photochromic materials are attractive and promising for applications in many fields. One subject in this area is to prepare and study the photochromism in composite or hybrid materials based on transition-metal oxides or polyoxometalates. Their properties not depend only on the chemical nature of each component, but also on the interface and synergy between them. Since the charge transfer plays a key role in the photochromism of these materials, it is very important to increase the charge (electrons, holes, and protons) interactions between the two components in either composites or hybrids. To realize this, one big challenge is to optimize the two components on a molecular or nanometer scale, which is closely relevant to the constituents, sample history (pre-treatment, preparation, and post-treatment), environment (humidity, presence of reducible or oxidizible matters, light-irradiation wavelength, intensity, time, etc.). Based on these, many novel composite or hybrid materials with improved photochromism, visible-light coloration, reversible photochromism, multicolor photochromism or, possibly, fast photoresponse, have been prepared during the last two decades or three. This may underscore the opportunity of using these composite and hybrid materials as the photonic applications. In present paper, we summarize thoroughly all the recent progress in these subjects.  相似文献   
89.
Polycrystal of GdPO4:RE3+ (RE=Tb, Tm) phosphors were prepared by solid-state method. Vacuum ultraviolet excitation and emission spectrum and the energy transfer mechanism between the host and dopants of Tb3+ and Tm3+ were investigated respectively. The emission of Gd3+ at 313 nm was enhanced by the strong absorption of CTS of Tm3+ at 180 nm in GdPO4: Tm. It has also been concluded that the excitation of Gd3+ is transferred to Tb3+ and then emission peaks of 5DJ7FJ of Tb3+ were observed.  相似文献   
90.
液压管路件作为液压系统的一个重要组成部分,在实际应用中经常会产生诸如渗漏、开裂等故障,就工程机械中常见液压管路件的故障产生原因进行了分析,并提出相应的解决办法。  相似文献   
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