二重点

Discrete and continuous random variables, theoretical distribution, expected value, binomial distribution and normal distribution, standardizing and normality.

间断性变数总体的理论分布重点掌握二项分布和泊松分布，连续性变数总体的理论分布重点掌握正态分布以及正态分布的标准化。

This paper deals with the advance in the study of terrestrial Permian-Triassic boundary. At first, some index TPTB sections and their research backgrounds are introduced. Then, the research status on the synthesis of the TPTB, including biostratigraphy, eventostratigraphy, isotopic dating, magnetostratigraphy and sequence stratigraphy etc., is analyzed. Finally, the existing problems and the next research directions about the TPTB study are assessed.

着重介绍了几个目前陆相二叠系－三叠系界线研究的重点剖面及其生物地层学研究进展；分析了陆相二叠系－三叠系界线综合地层学研究现状，包括生物地层学、事件地层学、同位素年代学、磁性地层学和层序地层学等；剖析了陆相二叠系－三叠系界线地层学研究中存在的问题及进一步的研究方向。

The discussion is focused on the feasibility of dimethyl ether used as a city gas and the price problem.

讨论了二甲醚生产的基本原理与工艺，介绍了二甲醚的主要燃料用途，重点讨论了二甲醚作为城镇燃气的可行性与价格问题。

The Oncology department of the 2th affiliated hospital of DaLian Medical University is the key medical science of DaLian city and LiaoNing province, an authorized doctorship site for M D.

大连医科大学附属二院肿瘤内科是辽宁省重点专科、大连市医学重点专科。博士、硕士学位授权点，已培养博士5名，硕士40余名。

Through the fusion and interpretation of three-temporal Landsat TM image (1987, 1998 and 2008) and two-temporal spot image (1997,2008), using the overlay analysis function of GIS, we made an analysis of land use change in Northern mining area of Xuzhou in the nearly 20 years.

文中重点是采用RS和GIS技术调查土地利用变化，建议增加解译之后的不同年代土地利用图。（2）表1、图二和表二图三存在表述对象相同的问题，建议删除图二和图三。

The problem from sodium tripolyphosphate,4A zeolite,sodium metasilicate and phosphorous prohibition was summarized and the various performances and effect of δ-layered crystal disodium silicate as detergent were analyzed.

分析了现用助洗剂三聚磷酸钠、4A沸石、偏硅酸钠存在的问题及禁磷的重要性，重点论述了δ-层状结晶二硅酸钠用作助洗剂的各种性能及效果，认为δ-层状结晶二硅酸钠是一种良好的无磷助洗剂，它具有其他助洗剂所不具备的优良性能；对δ-层状结晶二硅酸钠的制备工艺作了简要介绍，并作了市场及在国内工业化生产的可性行分析。

Present status and application of isoprene,cyclopentadiene and m-pentadiene in cracking C_5 fraction products were reviewed.

重点介绍了国内外裂解C5分离产物异戊二烯、环戊二烯和间戊二烯利用近况，提出C5综合利用具有很广阔的发展前景和现实意义。

Two important routes currently being used to improve molybdenum disilicide mechanical property and oxidation are the alloying approach and the doping approach.

介绍了二硅化钼合金化及掺杂改性的研究进展，对几种重要合金化元素和掺杂元素改性的二硅化钼材料进行了评述，并在此基础上提出了高性能二硅化钼材料研究开发的重点和方向。

The results of calculation will be fundmentally consistent with the experimental values.In addition, we calculated dibenzene chromium and its derivatives, ferroceneand its derivatives. The former had higher symmetry. We studied the substituenteffects by calculating their NMR spectra. The results show that: when we add asubstitute group on one ring of dibenzene chromium, the substitute group will affecttwo benzene rings. The effect is similar to the effect of branched alkanes, namely:the effect on neighbouring groups has transmissibility. Furthermore, the nearer theneighbouring group is, the stronger the effect is. This effect is observed not only onthe substituted ring, but also on the unsubstituted ring.

此外，我们重点计算了二苯铬及其衍生物和二茂铁及其衍生物的核磁共振谱，其中二苯铬及其衍生物选择的是对称性较好的体系，通过计算其核磁共振四川师范大学硕士学位论文谱，探讨其取代基效应，结果表明：在二苯铬的一个环上引入取代基后，取代基对两个苯环的影响，类似于支链院烃引入取代基后的影响：即对邻近基团的影响有传递性，并且对离得近的作用强，对离得远的作用弱，这种作用不仅体现在连有取代基的环上，也体现在没有带取代基的环上。

By employing the Jordan-Wigner transformation and a modified mean field method, we are able to determine its ground-state quantum phase diagram approximately. The chapter IV is the main part of this Thesis. It contains the main innovations in our work. We propose and study in detail a S=1 Ising chain with the interplay of single-ion anisotropy and dimerization. The main results and innovations are the following: We show that the total number of the zero-component of spins at each site is a conserved quantity. This quantity, which may intuitively called as hole's quantum number, is hidden in the system. We show further that the hole's number in the ground-state is zero; By using the Jordan-Wigner transformation, we map this model onto a series of subsystems described by the spin 1/2 dimerized transverse Ising model. We solve the subsystems exactly, by presenting the exact wave functions and spectra;We show that this system exhibits a series of quantum phase transitions by varying the dimerization strength. We determine the quantum critical points exactly. We also show that the criticality is the same as that of the uniform S = 1/2 transverse Ising chain.

第四章是本文的重点及主要创新内容，我们具体研究了自旋为1的在横向单离子晶格场中的一维二聚化Ising链，我们得到的主要结果和创新之处是：(1)证明了这一模型具有一种隐藏的对称性，即自旋第三分量为零的格点数目是一个守恒量，并证明基态出现在空穴数目为零的子空间中；(2)利用Jordan-Wigner 变换将此模型变换到一系列自旋为1/2的横磁场中的二聚化Ising 模型，并给出了相应严格的波函数及能谱；(3)我们发现系统的基态随着二聚化强度的变化将呈现出一系列量子相变，我们得到了量子临界点的精确位置，并证明其临界性质与自旋为1/2的横磁场中的均匀Ising 链中的临界行为属于同一普适类。

In the negative and interrogative forms, of course, this is identical to the non-emphatic forms.

。但是，在否定句或疑问句里，这种带有"do"的方法表达的效果却没有什么强调的意思。

Go down on one's knees;kneel down

屈膝跪下。。。下跪祈祷