查询词典 difficult problem

At present it is very difficult to predict all the RNA secondary structures. This paper describes RNA secondary structure prediction methods from 1970\' to this day in a systematic way some. Tracing back and following the tracks of prediction methods the author made a summary of RNA research progress and situation while a enumeration problem of RNA secondary structure is studied with the method of combinatorial enumeration.

目前所有有关RNA二级结构的预测算法要预测出所有序列的二级结构仍然很困难，本文系统介绍了从上世纪70年代以来发展至今的各类RNA二级结构预测算法，从对RNA结构预测方法的追溯和跟踪，对当今RNA研究的进展和形势做了一个总结，并且应用组合计数的技巧解决了一类RNA二级结构的计数问题。

Job-shop scheduling is a typical combinatorial optimization problem, and large scale scheduling optimization is one of such difficult optimization problems.

作业车间调度是一种典型的组合优化问题，大规模的调度优化是该类问题的难点。

This problem is so difficult that I can't come at it.

这个问题太难了，我不懂。

At present, the workers of the eighth oil plant use production logging method to determine single-layer's output and water cut of commingle producing well which produce Putaohua and Fuyu reservoir at the same time. This method takes a long period and high costs. And it's also difficult to determine single-layer's water cut. Aims at this problem, this present writer provides gas phase chromatogram fingerprint methods to determine single-layer's output.

针对目前采油八厂地区葡萄花、扶余两套合采油层采用生产测井方法确定分层产量及含水时成本高、周期长以及分层含水难以确定的问题，本文提出了应用气相色谱指纹技术来确定分层产量的方法。

Aiming at the problem that the condition information of large size steam turbine unit is complex and difficult to evaluate its condition accurately, an evaluation method based on evidential reasoning is proposed.

针对大型汽轮机组状态信息复杂，运行状态难以准确评价的问题，提出基于证据推理的状态评价方法。

Because of the complexness of the co-existence of unsteady three dimensional environmental flow and the jet flow, thorough study of the problem is difficult.

本文试图通过数学模型的方法对这一情况下的污水排放射流问题进行研究，为污水排海工程提供可行的参考模型。

Based on the higher mathematics method proved inequalities are summarized, and the proposed using the function extreme value and the monotonicity and concave and convex function sex, and mean value theorem, Taylor formula, integral these common higher mathematics method, combining with concrete examples of each kind of method to solve the problems for type, and the key problem of the specific steps, and points out that the inequality proof of higher mathematics method used properly, improve the difficult easy to ability to solve problems.

本文对不等式证明中的高等数学方法作了归纳总结，提出了利用函数的单调性，极值与最值，函数凹凸性，中值定理，泰勒公式，积分这些常用的高等数学方法，并结合具体实例阐述了每一种方法的适用类型、解决问题的关键和证明问题的具体步骤，指出在不等式证明中恰当地运用高等数学方法可以化难为易，提高解题能力。

It is extremely difficult to solve the problem of tunnel leak, because there are many muddiness, greasy dirts and slushes on the top of the tunnel, thereby it is hard to conglutinate the waterproof materials. Test results show that the impervious pressure and the splice strength of the acrylic acid waterproof material will be up to 1.2 MPa and 1.8 MPa in 30 min with new formula and unique construction craft 50 that reduce the difficulty of conglutination.

实验结果表明：使用新型丙烯酸防水材料配方和施工工艺，使丙烯酸防水材料的抗渗压和粘结强度在30 min里能够迅速分别达到1.2 MPa和1.8 MPa，从而降低粘结难度，很好地解决了既有隧道的顶部因有很多的淤泥、油污、水垢等杂物而使普通防水材料难以粘结的问题。

But, because of the complexity of the dye molecule, there has been short of detailed comprehension in its photocatalytic degradation process. The key problem is difficult to detect the intermediates clearly. In this paper, the photocatalytic degradation of azo dye Congo red in water solution was investigated on UV irradiating TiO2 in the homemade reactor. The optimization conditions were determined and then the rate of decolorization, COD decrease, yield of CO2 and varies pH of aqueous solution during illumination were detected; The varies of the possible intermediates during degradation process were monitored with UV-VIS spectrum and HPLC. The possible mechanism of Congo red photocatalytic degradation is discussed combined with the data of MS.

本文选择有代表性的常见偶氮染料—刚果红作为研究对象，以自制TiO2为催化剂和小功率紫外灯为光源，在自制光反应器上确定了光催化降解的优化条件，并在这个优化条件下测定了降解过程中的脱色率、COD去除率和CO2生成量；利用数显酸度计、紫外可见分光光度计和高效液相色谱仪跟踪测定了降解过程中的可能产物，并结合质谱的数据初步探讨了刚果红的可能降解机制。

This complicates matters, for it is difficult to arrive at a common mind on the sacrifices that ought to be demanded of us in order to face the ecological problem in our consumerist society.

这样的态度，使事情变得非常复杂，因为，人们无法在「为了生态而牺牲」的态度上取得共识。然而，我们应该要求自己在这个消费主义的社会里，正视生态的问题。

In the United States, chronic alcoholism and hepatitis C are the most common ones.

在美国，慢性酒精中毒，肝炎是最常见的。

If you have any questions, you can contact me anytime.

如果有任何问题，你可以随时联系我。