查询词典 difficult point

Based on consider hereinbefore, this dissertation discusses several aspects on the problem of the sustainable and optimum exploitation of groundwater resources as follows:①reviewed entirely the origin and evolvement of the concept "sustainable development", stated and commented the study status in queue on"sustainable development"around national and international range, thorough discussed the science connotation about the concept "sustainable development";②looked back and commented across-the aboard some furthest basic concept and proposition related to groundwater resources, put forward self opinions on a few existent mistake points of view and chaos understandings;③expatiated entirely on the content and meaning of the theory of changeable groundwater resources system, contrast with the traditional methods of groundwater resources calculation and evaluation, combined example to show the application of this theory;④thorough analyzed the difficult and complexity to forecast the groundwater resources, fully stated the traditional methods of groundwater resources forecasting, pointed out the characteristic and applying condition of these forecasting method, introduced the main ideas and methods of wavelet analysis developed recently, and the MATLAB software be known as the fifths era computer language, and its accessory wavelet analysis toolbox, applied these methods and tools to analyze the groundwater dynamic curve, adopted the B-J method and Morte-Carlo method, combined with the theory of changeable groundwater resources system, discussed the new view on the forecast of groundwater resources;⑤synthetically analyzed the characteristics and limitations of the present all kind of groundwater manage model, combined mathematical programming, mathematical statistics, random process and the theory of variation system of groundwater resources on the unite optimum attempter of surface water and groundwater, emphasized how to make the model more nicety, more simple, more practicality;⑥analyzed the inside condition and outside condition to assure the sustainable and optimum exploitation of groundwater resources, the inside conditions are the follows: correct resources idea, scientific methods of resources calculation and evaluation, credible forecast methods of resources, exercisable measures of resources management, the outside conditions are the follows: the development idea of high layer, the transform of manage system, the matched policy and rule of law, the adjusted of economy lever, the improve of cultural diathesis, the boosting up of water-saving consciousness and detail measures, the control of population rising, the prevention and cure of water pollute, the renew and rebuild of ecology;⑦scan the sustainable and optimum exploitation of groundwater resources from the high level of metagalaxy, earth system science, and philosophy;⑧point out the more directions on groundwater resources.

它将为制定水资源的可持续发展目标和战略决策提供科学依据，为制定社会、经济可持续发展战略提供理论基础。基于以上考虑，论文主要从以下几方面对地下水资源可持续开发问题进行了比较深入的探讨：①全面回顾了"可持续发展"概念的由来与演变，对国内外"可持续发展"的研究现状进行了述评，并对"可持续发展"概念的科学内涵进行了深入探讨；②对涉及地下水资源的一些最基本的概念和命题进行了全面的回顾和评述，对目前仍然存在的一些错误观点和混乱认识提出了自己的见解；③全面阐述了地下水资源变值系统理论的内容和意义，并与传统的地下水资源计算评价方法进行了对比分析，结合实例具体说明了方法的应用；④深入分析了地下水资源预测预报工作的极端重要性和复杂性，对传统的地下水资源动态预测方法进行了全面的评述，指出了各类预测预报方法的特点及适用条件，对最近二十多年刚发展起来的小波分析技术的主要思想和方法及其应用范围，以及号称第五代计算机语言的MATLAB软件和附带的小波分析工具箱进行了介绍，并应用于地下水动态过程线的分析，采用时间序列中的B-J法，蒙特卡罗方法，与地下水资源变值系统理论相结合，探讨了地下水动态资料分析和地下水资源预测预报的新思路；⑤综合分析了现今各类地下水管理模型的特点及缺陷，将数学规划、数理统计、随机过程等与地下水变值系统理论相结合进行地表水地下水或多水源的联合优化调度，使模型更准确、更实用；⑥对保证地下水资源可持续开发的内部条件和外部条件进行了分析，内部条件主要是正确的资源观，科学的资源计算与评价方法，可靠的资源预测预报技术，可操作的资源管理措施，外部条件主要是高层发展思路、管理体制的变革、配套的政策法规、经济杠杆的调节、人文素质的提高、节水意识的增强及具体节水措施、人口增长的控制、水体污染的防治、生态的恢复和重建等；⑦从宇宙科学、地球系统科学及哲学的高度审视地下水资源的可持续开发；⑧指出了地下水资源可持续开发的进一步研究方向。

Due to the long distance, the target may appear as a dim point and has no feature information like shapes and textures. Furthermore, aero-optic disturbances and air turbulence make the SNR of a single image very low in the real environments. All of above make the miss distance of the missile difficult to estimate in shooting range.

针对目前靶场所面临的测量目标小、距离远、目标与背景对比度小，不具有形状信息的实际问题，提出了一种基于多帧相关技术与波门选通技术相结合的快速目标识别与跟踪方法，特别探讨了多帧相关技术中目标确定的理论判据，并综合考虑目标的尺寸因素和目标的运动特征研究了一种新的波门设定方案。

The algorithms based on two necessary condition is monotone decreasing, for multi-extreme point in solution space, the distribution of final codebook seriously depend on that of initial codebook, it is difficult to cast off if get in local optimality.

然而这些算法本身属单调梯度下降算法，在解空间存在多极值点时，最终码书的分布较大依赖初始码书分布，一旦落入局部最优区域，很难摆脱。

Numerous impermeable underground structures exist in urban seepage field. Since the corner of the structure is singular point and the dimension of the structure is negligibly small compared with the whole urban seepage field, it is difficult to model seepage field in urban area with existing methods.

城区渗流场中地下阻水结构物众多，由于结构物角点为奇异点，而且结构物的尺寸跟整个渗流场的尺寸相比起来非常小，这导致现有的计算方法难以对城区渗流场进行模拟分析。

There are other places on the planet that are difficult to live, and that's at the null point .

有其他地方的这个星球是很难活，那就是在空点。

Xie-Beni index decreases with the number of partitions increasing. It is difficult to choose the optimal partition of data when the number of clusters is large. From the point of view of the compactness and the separation of clustering, a novel clustering validity function is proposed, which is based on the improved Huber Г statistic combined with the separation of clustering.

针对此问题，分别考察改进的Hubert Г统计量和聚类分离度，导出一个新的基于数据几何结构的聚类有效性函数，使得它有惟一的最大值，函数值随聚类个数增大而递减的趋势并不影响最优聚类个数的判定。

It is difficult to say at which point our friendship gives way to business opportunism or pressure form above.

很难说清楚友谊是在什么时候由于考虑自身的眼前利益或来自上司的压力而中断。

Absolutely can not, because you can not underestimate the importance of not have a rice whether he fully chewing, and even if you see he has not finished chewing, he would swallow来不急also get you out, if a child's organ tender points, Small point, then you may be obstructive respiratory, such consequences are difficult to predict..

绝对不能，因为你不可能没一粒米饭都看轻他是否充分咀嚼了，就算你看到他没有咀嚼完，他要是咽下去了你也来不急去取出来了，要是孩子的器官嫩点，小点，那么就有可能阻塞你呼吸器官，这样后果很难预料。。

The appearance of end products from the point of view, it is difficult to differentiate the product is organic or conventional products.

从终端产品外观上看，很难区分该产品是有机产品还是常规产品。

Hope that past master can point out my mistake down , make me absent in a difficult position.

希望高手可以指出下我的错误，使我不在狼狈。

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。