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101.
叶蔚 《东北大学学报(自然科学版)》2004,25(Z1):103-106
现代企业制度的建立,使得公司的规模越来越大,集团公司内的管理越来越复杂.提出基于成本的动态管理模式,可以使集团公司内外部协同运作,有效的降低公司的运营成本,创造竞争优势. 相似文献
102.
张玉聪 《河北师范大学学报(自然科学版)》1998,22(3):384-386
利用统计因子直接计算法讨论了反应过程中分子结构的变化对熵变的贡献及对多元酸平衡常数的影响。 相似文献
103.
卓尼土司与中央王朝的关系非常紧密,各代土司均以自己独特的方式和中央王朝保持友好和建立臣属关系的同时,发展壮大了自己。文章试图从历代土司与中央王朝建立各种关系的过程入手,研究卓尼土司制度在这一地区发展壮大、长盛不衰的历史和原因,说明卓尼历代土司的见识和胆略,能以大局为重,定位准确。 相似文献
104.
针对XML schema不能直接转换为关系模式,笔者设计了结构字典存贮结构信息和约束信息,利用贪心算法实现了机制映射为关系模式.实验结果表明:结构字典和算法对重构XML文档提供了有力支持. 相似文献
105.
In this study, an adaptive asymptotic tracking control problem is considered for stochastic nonlinear systems with unknown backlash-like hysteresis. By utilizing backstepping technology and bound estimation approach, an adaptive asymptotic tracking control scheme is designed, where fuzzy systems are applied to approximate unknown function terms, the effect of hysteresis and stochastic disturbances is compensated appropriately. The proposed scheme ensures that the tracking error can asymptoticall... 相似文献
106.
系统研究了碱金属、铵离子和烷基胺在磺酸型阳离子交换树脂柱上以有机酸和无机酸为淋洗液的保留行为.比较了草酸、柠檬酸、酒石酸三种有机酸在洗脱碱金属、铵离子和烷基胺时的差异,研究了有机酸和无机酸浓度对离子保留值的影响.在磺酸型阳离子交换树脂柱上,以有机酸或无机酸为淋洗液均可以同时分离碱金属离子(Li^ 、Na^ 、K^ )、铵离子和烷基胺(甲胺、乙胺、正丙胺).淋洗液中起淋洗作用的阳离子是H^ .溶质阳离子容量因子对数值与淋洗液中淋洗剂阳离子H^ 浓度对数值之间具有良好的线性关系,直线斜率近似为-1,与文献中溶质保留值方程完全相符.碱金属、铵离子和烷基胺的保留行为符合离子交换机理.随着淋洗液浓度的增加,溶质保留值减小,但溶质的洗脱顺序不变. 相似文献
107.
Under most microscopes, the fluorescent sig- nals emitted from biological structures, such as vesicles, as well as the signals from single molecules will appear as small puncta, which contribute to a Gaussian-like distri- bution. Accurate segmentation of these spots will funda- mentally affect our interpretation of a specific biological progress. Because of the complicated backgrounds in images, many algorithms fail to identify all of the inter- esting signals; the tremendous amount of time required for algorithms to process large datasets can also decrease their utility. Here, we introduce an excellent robust detection method based on the machine learning algorithm Ada- Boost, which outperforms threshold-based segmentation, wavelets, and FDA under most situations. We also provide a GPU/multi-core CPU implementation of this algorithm; this implementation accelerates the algorithm approxi- mately 10- and 7-fold acceleration compared with a single CPU implementation. The great reduction of time should make this method a promising candidate in the processing of large datasets. Furthermore, we demonstrate the use of our algorithm on true fluorescent micrographs, and the results show that machine learning-based detection meth- ods outperform the four other previously reported methods. 相似文献
108.
Yinhu Xi Yuan Zhou Wei Zhang Junhong Mao 《科学通报(英文版)》2014,(29):3912-3918
Friction behaviors of linear rolling guides (LRGs) are determined by many factors and are crucial for precision positioning. It is difficult to create an expression to describe the friction behaviors exactly and completely. A new experimental method for measuring the friction behaviors of one LRG individually was developed, and linear motor direct drive technology is utilized in the experiment setup. The position signal is acquired by a grating, and the friction of the LRG is deduced by the product of the mass of the moving part and its acceleration. In the experiment, the LRG can move with the friction only, and the friction transition from normal rolling to pre- rolling stage was detected. The asperities' deformations were utilized to explain it. Hysteresis loops and internal loops were measured. The results indicate the non-local memory of the LRG, and the historical trajectory have an important impact on the friction behaviors of LRGs in the pre-rolling stage. 相似文献
109.
In order to improve removal for nitrogen in a pilot-scale submerged membrane bioreactor (SMBR), intermittent aeration was conducted, and the effect on the treatment performance under four kinds of operation condition (run 1, continuous aeration; run 2, 60/60 min aeration on/off time; run 3, 60/90 min aeration on/off time; run 4, 60/75 min aeration on/off time) was evaluated. The results showed that depending on the specific on/off of the aeration time ratio, removal efficiency of nitrogen could be improved significantly, and the removal rates of total nitrogen (TN) under different operation conditions were 28.0%, 59.5%, 66.8% and 70.7%, respectively. There were no obvious differences for removal rates for CODCr and ammonia among different operation conditions. In general, intermittent aeration could be used as a feasible way to improve treatment performance for nitrogen in the SMBR. 相似文献
110.