经济困难的

Owing to the facts that the marketing price of coal in China is much lower than its real productive cost, and the price ever determined is by no means considering the demand and supply situations of the market, to make the economic appraisal of capital construction projects in Coal mining is still a hard nut to crack.

由于现行的煤炭价格低于煤炭的实际生产费用，且在确定煤价时没有考虑煤炭产品的供求情况，致使煤炭建设项目的经济评价遇到了巨大的困难。

Also the relative study on domestic economic problems with Markov switching model is very exility.

虽然，Markov机制转换模型及其扩展在宏观经济和金融等领域的应用取得了较大的成功，但由于该模型的参数估计比较困难以及相关检验方法存在一定的缺陷，从而导致其应用相对于一般的线性时间序列模型而言仍不够普遍，国内对Markov机制转换模型的相应研究则更为稀少。

In chapter 4, the case of risk asset allocation with allowed sell and restricted short sell is discussed, especially in case of restricted short sell, the efficient frontier piecewise partition is determined by using duality theory in parametric quadratic programming. And the concept of tripartition is introduced, economic meaning stated and algorithm to determine efficient frontier proposed.

特别对限制卖空的证券组合，应用参数二次规划对偶性理论解决了有效边缘曲线分片划分的问题，并引入了三元分割的概念，解释其经济意义，同时给出确定有效边缘的算法；对于协方差矩阵是奇异的情况，利用矩阵分块技术，得到不同情形下有效边缘的解析表达式，并用直观的几何图形描述，克服了M-V模型在实证分析中遇到的困难。

Firstly, because of more and more pipelinesintersect underground, it becomes very difficult to perambulate. Secondly, the leakageof underground pipeline may cause a series of serious problems, such as loss ofenergy and money, pollution of the environment and even danger to life. The reasonsof leakage mainly include two aspects.

其一，埋地管道不断增加，纵横交错，使管道巡线变得越来越困难；其二，土壤对管道的腐蚀，自然力的破坏等原因而产生的漏油，以及人为的损坏和偷油等，都造成巨大的能源浪费和经济损失，更可能引发环境污染和严重的安全事故。

The higher life quality the grandmother have, the higher will they accept to grandparent in the future.(4) From the results of multiple regression, the total variances that the family member characteristic and grandparenting behavior can explain is about 24.5%. The priority of the variances are as follows. 1.The characteristics of grandmother (including age, education, spouse condition, economical condition, income and the type of living, 17.1%). 2.The difficulty of childcare (6.8%). 3.The characteristics of parents (including marriage condition and if the parents assit childcare, 3.1%), 4. The types of childcare (1.8%), 5. The age of grandchildren (1.0%). 6. The reason of childcare (for the child, for the parents or for the grandparents, 0.5%). 7. The assistance to childcare (0.3%).

经由多元回归分析，家庭人口特徵、带孙行为可解释生活品质的总变异量为24.5%，各变项可解释的变异量依序为祖母人口变项（含祖母的年龄、祖母的教育程度、祖母是否有配偶、自觉经济状况、生活费来源、居住型态）（17.1%）、照顾的困难程度（6.8%）、孙子女父母相关变项（含孙子女父母是否为已婚或同居、孙子的父母是否提供协助、父母是否因工作而未自行照顾）（3.1%）、照顾类型（区分为全职照顾、日托照顾、半日托照顾、兼职照顾）（1.8%）、照顾孙子的年龄（1.0%）、照顾理由（区分为为孙子著想、为孙子女的父母著想、为祖母自己著想）（0.5%）、有无照顾协助者（0.3%）。

But for they are smaller in size, have less capital and less completed technology construction, and more easily to be influenced by exterior macro economic changes, their financial management has been unadapted to their own development and the market economy, which has led to great difficulties in dealing with the fierce market competition.

但由于中小企业规模小、资本和技术构成较低、外部宏观经济变化对其影响大等因素的存在，使其在财务管理方面存在与自身发展和市场经济均不适应的情况，导致其在应对激烈的市场竞争面临巨大的困难。

To attain this goal, we need to address the problems in unstable, uncoordinated and unsustainable economic development.

目前最大的困难是物价过快上涨和通货膨胀的压力，隐藏的风险是经济可能出现的波动，我们必须在这两者之间走出一条光明的路。

On the other side, the macroscopical condition of the world is instable, and many disharmonious elements act as resistance and challenges to the Communist League, and produce problems such as the infirmness of organization, the league building in non-public-owned corporations and the organizing difficulties caused by reformation of education and economy system.

另一方面，世界的大环境并不安定，各种不和谐因素给共青团组织带来新的阻力和挑战，产生了更多的新问题，如组织弱化，非公有制企业团建，教育体制改革、经济体制改革带来的组织困难等问题。

The traditional fiber optic cable line maintenance management pattern breakdown search difficulty, the platoon bonds the time to be long, affects the communications network the normal work, the economic loss which creates because of the correspondence optical cable breakdown is huge every year.

传统的光缆线路维护管理模式的故障查找困难，排障时间长，影响通信网的正常工作，每年因通信光缆故障而造成的经济损失巨大。

Some countries have small or relatively inaccessible reserves, or no known reserves at all, and so have to offer favourable terms to entice foreigners' interest. Other states might seem like risky places to do business of any kind (thanks in some instances to past nationalisations of the oil industry) and must therefore offer preferential terms to woo investors. Others agree to sacrifice some of their take for the sake of creating extra jobs or diversifying the economy.

有的国家的石油储量比较少，或者是比较开采难度较大，抑或根本就没有已知储量，所以它们就抛出诱人的条款来吸引外资；还有一些国家则可能是处于比较危险的地理位置，从而使得与任何一方作交易都比较困难（某些情况下得感谢石油工业的曾经国有化），它们也不得不制定优惠条款来吸引外资；考虑到能创造就业机会或者带来经济多元化，其它有些国家权衡之下也会同意牺牲部分利益。

This one mode pays close attention to network credence foundation of the businessman very much.

这一模式非常关注商人的网络信用基础。

Cell morphology of bacterial ghost of Pasteurella multocida was observed by scanning electron microscopy and inactivation ratio was estimated by CFU analysi.

扫描电镜观察多杀性巴氏杆菌细菌幽灵和菌落形成单位评价遗传灭活率。