难解的

The results show that quartz cannot react with oleic irons at pH=8-10, because it is difficult to combine with metallic irons. On the contrary, clinochlore can adsorb with oleic ions because there are enough active metallic positive ions between the minerals layers which can combine with clinochlore. The clinochlore can be hydrophobic, and so the separation can be realized finally. At pH=9, the clinochlore removal rate is the maximum, the purity of SiO2 is 99.86%, and the recovery of SiO2 is 35%.

结果表明：在pH为8~10的碱性溶液中，粉石英难与金属阳离子缔合，所以，不与油酸根离子结合；而斜绿泥石解离后层间存在活性金属阳离子，可与油酸根离子发生化学吸附产生疏水作用，因而使用反浮选的方法能有效地实现二者的分离：当pH为9时，斜绿泥石的去除率最高，粉石英的纯度达99.86%，回收率为35%。

The results show that:Changing the substituents of the phenyl rings,on the one hand,will influence the capacity of conjugation of the phenyl rings through S→N dative bond and furthermore influence the weak acid-dissociation of phenolic hydroxyl,on the other hand,will influence the geometric conformation of the compound and furthermore influence to form structure matched with membrane and water/membrane.

结果表明：改变药物化合物两边苯环上的取代基，一方面，将影响苯环通过S←N授受键的共轭能力，进一步影响酚羟基的弱酸离解常数；另一方面，将影响C-S，S-N键自由旋转的难易程度，进一步影响到能否形成与膜/水膜界面相匹配的结构。

It is impossible for him to solve this maths problem. It is pretty easy for me to get a good job. It is said that our school will hold a sports meeting next month.

处理这件事情是很难的。2、你开车这么快是很危险的。3、他解出这道数学题是不可能的。4、我要找一份好的工作，这将会相当的容易。

Classic technique is the Newton-Raphson iterative. But when the system grows much bigger, the computing is much more hugeness. And it is very difficult to get the result in a short time under the current hardware and software situation.

经典的潮流计算方法是采用牛顿拉夫逊法迭代计算，但是随着电力系统的规模的增大，计算量异常庞大，在现有的软硬件的很难在短时间内得到潮流计算的解。

The entropy is a very important concept in physics, mathematics and system science. The problem of its minimum value under the condition of constraint is NP-complete and can't be analytical solved.

熵是物理学、数学、系统学等学科中一个非常重要的概念，在约束条件下熵的最小值问题属于NP难的组合优化问题，一般无法得到此问题的解析解。

It has been proved that the grid job scheduling is a NP-complete problem, and it is hard to find an optimal solution in polynomial time by using traditional searching method.

已有文献证明，由于网格的复杂多变和任务的层出不穷，网格中的任务调度属于NP完全问题，很难用传统的搜索办法在多项式时间内找到最优解。

Because of the development of chemical fabric, rising of artificial technology and making progress of technology, which are the reasons of making a amount of the difficult biochemistry degrade of PVA serosity, artificial silk alkali solve matter and new-type auxiliary thing to enter into dyeing wastewater in recent years, and COD rises 2000-3000mg/L.

近年来由于化学纤维织物的发展，仿真丝的兴起和印染后整理技术的进步，使PVA浆料、人造丝碱解物、新型助剂等难生化降解有机物大量进入印染废水，使COD浓度从原来的数百毫克每升上升到2000-3000mg/L，从而使原有生物处理系统COD去除率从70%下降到50%左右，甚至更低，传统的生物处理工艺受到严重挑战，作为纺织品的生产，其生产过程关系到人们生活的大环境。

The analyses of electronic structures shows that the catalytic reactivities for H2 adsorption of the different surfaces are dependent on the numbers of s orbital bonding electrons around Fermi level for the uppermost layer metal atoms which interact directly with H2. It is easy to form vacancy for hydrogen atoms next to iron atom, which indicates that hydrogen atom cannot be escaped, but it is difficult to from vacancy for hydrogen atoms next to magnesium atom, which indicates that hydrogen atom can be escaped. Hence it is thought that the change of dehydrogenating properties of MgH2 with or without a little iron addition attributes to the weakened bonding between magnesium and hydrogen.

分析电子结构发现：空位缺陷有助H2吸附于Mg表面，与Mg(0001)表面最上层与H2直接产生吸附作用的金属原子在费米能级附近s轨道的成键电子数密切相关；在Fe合金化MgH2体系中，与合金化元素Fe近邻的H原子形成空位的难度增加，H原子较难释放；与Mg近邻的H原子形成空位的难度减少，H原子容易释放；Fe合金化导致Mg-H之间存在较弱的成键作用，因此，MgH2体系的解氢性能得到提高。

That means you may find it is very difficult to tenderize the tough outer layer of lean meat on belly pork.

倘若要猪腩肉肥而不腻、入口即化，秘诀是切除猪腩肉的底层肉，原因在於现在的猪肉肉质有别於当年，尤其猪腩肉的底层肉特别难焖得软嫩，就算加长焖的时间，亦不能解此问题，只会将猪腩肉肥的部分煮融，瘦的部分仍然乾及硬，切除的底层肉可以留起放汤。

Only in the case of the February Revolution do we lack a useful description of participants that might characterize it in the light of what social history has taught us about the process of revolutionary mobilization.

杨鹏 GRE 阅读难句精解 44 唯独在二月革命这一情形中，我们缺乏一种有用的有关参加者的描述，而这一描述则有可能按照社会历史有关革命动员过程所教给我们的内容来勾画出这场革命的性质。

The absorption and distribution of chromium were studied in ryeusing nutrient culture technique and pot experiment.

采用不同浓度K2CrO4(0，0.4，0.8和1.2 mmol/L)的Hoagland营养液处理黑麦幼苗，测定铬在黑麦体内的亚细胞分布、铬化学形态及不同部位的积累。

By analyzing theory foundation of mathematical morphology in the digital image processing, researching morphology arithmetic of the binary Image, discussing two basic forms for the least structure element: dilation and erosion.

通过分析数学形态学在图像中的理论基础，研究二值图像的形态分析算法，探讨最小结构元素的两种基本形态：膨胀和腐蚀；分析了数学形态学复杂算法的基本原理，把数学形态学的部分并行处理理念引入到家实际应用中。