Note that in some cases , publishing a pointcut for external use encourages structuring code in a particular way so that a simple pointcut definition can be exposed that represents a sequence of join points in the implementation 注意，在某些情况下，发布切点供外部使用需要以特殊方式对代码进行结构化，从而暴露简单切点定义以表示实现中的一系列连接点。
Genes coding mature peptide of igfs were achieved by pcr using another pair of oligo - nucleotide primers to induce to the suitable restriction enzyme site , and the igf - i product of pcr contains 230 base pairs . igf - ii contains 219 base pairs . 3 各另外设计一对特异性pcr引物，导入适当限制性内切酶切点，以上述连有目的基因的克隆载体为模板，采用pcr方法扩增基因片段，获得长度约230bp的igf -和219bp的igf -成熟肽基因序列。
The great tour purchasing power is the drive power of promoting the region ' s tourism developmentln the regional space , scale economic and regional separation are one of the basic characteristics of promoting tourism industry , so we must arrange the regional tourism industry with a systematic method and give prominence to the central city . for its outstanding area in the regional space , central city has evident superiority in the regional ecnomic development , and has echelon between central city and its periphery scennic spots , which is the inducement mechanism of tourism industry ' s arranging , developing and advancing step by step . for the law of diminishing marginal utility and the theory of equilibrium , the max utility equilibrium of tourism consumption be at the point of tangency of undiscrepancy curve and the cost budget curve 中心城市居民巨大的出游力是拉动其周边旅游地发展重要的内在驱动力；由于地缘关系，区域规模经济与地域分割并存，是旅游产业运动的一个基本特征，为此必须对区域旅游经济进行系统化布局，突出中心城市的产业中心性；因其区位条件独特，中心城市在区域经济发展中居于明显的优势，与周边城乡部位存在经济发展上的梯次性，这种梯次性是区域旅游生产力布局、产业发展梯次传动，最终整体联动的经济诱导机制；根据边际效用递减规律和旅游者最大效用均衡理论，旅游消费效用最大化的均衡在无差异曲线与开支预算线的切点(即旅游目的地选择的最佳位置)上，且随着边际效用递减，目的地选择的最佳位置向远离中心城市方向移动，这就是中心城市与周边旅游地互动关系的经济学解释。
The first part is introduction , presenting this paper ' s structure , research background and so on ; the second part introduces some issues relating closely to risk , the tangency point between indifference utility curve and efficient frontier is the optimal portfolio ; the third part explores risk evaluation , this part begins with some risk factors affecting security ' s price and return , then analyzes the methods evaluating degree of risk , finally , introduces a more popular method of risk evaluation - - var ; the forth part expounds risk management , this part studies some risk control strategies correspond to specific risk mentioned above ; the last part put forward some advice contrapose issues existed in risk management in china 第一部分为绪论，介绍本文的相关背景；第二部分是与风险相关的几个问题，等效用曲线与有效边界的切点是投资者选择的最佳投资组合；第三部分是风险衡量，该部分首先分析了证券与股票所面临的风险，然后对债券和股票分别介绍，最后介绍了目前比较流行的风险衡量方法? ? var方法；第四部分为企业风险管理，这里针对上文所述的风险提出相应的风险控制策略；第五部分针对目前我国风险管理中存在的问题提出了几点建议。
Moreover , i make the positive analysis with the actual date of our security market . by means of quadratic programming , i get the efficient convex and portfolio at the point of tangency . through the aggression , i get the portfolio of sim at the point of tangency 在此基础上使用我国证券市场的实际数据，运用二次规划方法求解了马柯维茨有效边界和切点组合；用回归的方法求解了单指数模型的切点组合；用二步回归的方法初步检验了资本资产定价模型；使用三业绩指数，对我国的基金进行业绩评级。
