有困难

Unless you have a good knowledge of astronomy, which I do not, this is difficult.

除非你有很好的天文学知识，我并不懂天文学，那就很困难。

It's much tougher to break teams down now because they are more organised and tactically more astute.

击败一支球队是困难的，因为对手都是有组织的而且也用脑子踢球了。

You are at work in the most difficult tasks which

您感到在工作中最困难的工作有哪些？

Though barriers may at whiles stand in the way of your dreams, remember those your destiny is hiding behind them.

尽管通往梦想的道路上总有坎坷，你需求记住的是，你的命运就隐藏在那困难背后。

With the new concept,the problem of variable structure control of 2D discrete system is transferred to the problem of seeking a sliding model with good sporting character and attractability. The concrete design schemes of the imitative sliding model and variable structure controller are also put forward. And the concrete expression of the time T in ε-neighborhood of reaching switch manifold is obtained. The difficulty of applying the existing methods to MIMO systems is overcome.

在新概念之下，将2D离散系统的变结构控制问题转化为寻找一个既具有良好的运动品质又具有吸引性的滑动模问题，给出了滑动模及变结构控制器的设计方案，并且获得了达到切换流形的ε领域的时间T的具体表达式，克服了已有方法难以应用到多输入—多输出系统上的困难。

In chapter 2 of this dissertation, we give the mathematical definition of selfsimilarity, and describe some of its properties. How to justify a self-similar process and get its autocorrelation coefficient (or self-similar parameter) are also discussed.

由于对于非马氏过程的排队系统进行数学分析是十分困难的，因此，对自相似业务流特性及网络性能的研究，大多采用某种近似的数学求解，或直接进行计算机仿真，这就需要有快速、准确的自相似序列生成方法。

In the light of cost index and pollution degree, the characteristics of kinds of pulp are analyzed in detail, and the GP pulp which is low cost, high-yield, no-pollution is chosen as the material of tableware. Based on material element analyzed, shaping technology is designed, the to and for single plane shaping equipment which is high shaping quality, high production efficiency and is easy to automatize is chosen. All kinds of measure are taken to solve the problems which are inequality in the shaping process of GP pulp, and dosage which matches with GP pulp is chosen. Some ways of fixing shape and heat up are analyzed, the technology of saving energy of heat pressing to fix shape being composed of oil heat and only one fixed shape in the mold is applied, with which it is high production efficiency, low cost to fix shape effectively, which saves energy 30 percent. In order to make the production line meet with material of GP pulp, measure are taken to solve the problem of pulp adhered to netlike molding which can lead to carry material difficult, the structure of fully automatic equipment is renovated, the loaded beam is optimizationally designed to make equipment structure compactand improve location precision and products quality. According to technologic flow and actual characteristic, Omron PLC is chosen as the core of the control system, proximity switch as detect unit take the place of touch switch, software is designed reasonably according to time order figure, hardware is simplified, the reliability of system is advanced, the stability of system is assured to make production order. Intelligence neuron PID system is studied theoretically which is made up of both neuron with self-organizing and self-learning function and ordinary PID with the characteristic of the simple structure and high stability, which can automatically tune the parameter with the change of system parameter, remain perfect performance.

按成本指标和污染程度分析各浆料的特点，选择低成本、高得率、无污染的磨石机械浆为原料，在原料组分分析的基础上，设计成型工艺，选择成型质量好、生产率高、易实现自动化的往复式单板成型机，采取各种措施解决GP浆成型不均匀的问题及选择与机械浆相匹配的助剂；分析几种定型方式和加热方式，采用定型效果好、生产率高、成本低的油加热与模内一次性定型相结合的热压定型节能技术，节能30％；为了使生产线适应磨石机械浆原料，采取相应措施解决由于粘网造成物料转移困难，对全自动设备结构进行改进设计，着重对物料传送系统的关键部件——承载梁的进行优化设计，使设备更加紧凑合理，提高设备的定位精度和产品质量；根据生产线工艺流程和现场特点，选用OMRON CPM1A型PLC为主核心，接近开关作为检测元件，替代有触点开关，选用可编程终端代替常规面板按扭，并按照时序图科学合理地设计软件，有效地简化系统硬件构成，提高系统的可靠性，保证系统的稳定性，从而使生产更加通畅有序；从理论上探索将神经元应具有的自组织、自学习要求与PID控制结构简单、稳定性好的全自动纸浆模塑餐具生产线的研究特点结合起来，构成神经元自适应PID控制器，当参数的变化时，系统能自行参数整定，保持优良的工作性能指标，满足实际需求。

After autoxidation, the toxic metabolite 1-methyl-4-phenylpyridinium is formed and cause damage to the dopaminergic neurons.

对黑质-纹状体多巴胺神经传导途径有高度专一性的伤害，能引发与人类巴金森氏症相似的颤抖、肌肉僵直及起始运动困难等症状。

IDC should compete for this market now very big, a lot of is facing difficulty and baleful competition.

IDC现在这个市场来说应该竞争很大，有很多面临着困难和恶意的竞争。

We know the Barclays Premier League is one of the hardest leagues in the world and every team is good with good players.

"我们知道英超是世界上最困难的联赛之一，每个球队都有优秀的球员。"

For a big chunk of credit-card losses; the number of filings (and thus charge-off rates) would be rising again, whether

年美国个人破产法的一个改动使得破产登记急速下降，而后引起了信用卡大规模的亏损。

Eph. 4:23 And that you be renewed in the spirit of your mind

弗四23 而在你们心思的灵里得以更新