正

The second lens group includes a 2nd-group 1st positive lens, a 2nd-group 1st compound lens formed by joining a 2nd-group 2nd positive lens having a convex surface on the image plane side and a 2nd-group 1st negative lens having a concave surface on the screen side, and a 2nd-group 3rd positive lens arranged in that order from the screen side toward the image plane side.

第二透镜组包括一个第2组第一正透镜，一个由在像平面侧具有凸面的第2组第二正透镜和一个在屏幕侧具有凹面的第2组第一负透镜结合的第2组第一组合透镜，和一个第2组第三正透镜，它们以从屏幕侧到像平面侧的顺序布置。

In DMMCS, there is an alternative distribution of inertial instability column and inertial stability column, at the west and south, there lie negative CVV columns, while negative CVV column is beneficial to deep moist convection.(4) The strong slantwise convection induced by inertial instability, baroclinic instability and conditional symmetry instability will enhance the upper level southerly component. Because of the appearance of the compensated downdraft at the low level of the south side of DMMCS, the low level southerly is intensified, the enhancement of upper- and low-level cores are in favor of the development of DMMCS. And that will do favor for the reinforcement and maintenance of inertial instability, baroclinic instability and conditional symmetry instability, it is a positive feedback process.

深湿对流系统中高层西侧为负MPV2 柱，东侧为正MPV2 柱；(3)深湿对流系统中惯性不稳定柱与惯性稳定柱相间分布，西侧为负CVV 柱，东侧为正CVV 柱，负CVV 柱对深湿对流起激发作用；（4）惯性不稳定、湿倾斜不稳定和条件不稳定产生强的倾斜式对流，而强的倾斜式上升运动加强了深对流系统北侧高层的南风分量，因深对流系统南侧低层出现补偿性下沉气流，因而低层南风加强，高低空急流中心的加强会进一步加强对流的发展，使得惯性不稳定、湿倾斜不稳定和条件不稳定增强和维持，这是一个正反馈过程。

This article takes the teaching of conic sections as an example. By designing worksheets, teachers can introduce the historical material about conic sections to students. By way of using Apollonius' definition of parabola, ellipse and hyperbola, teachers can introduce the geometric aspect of "conic section" to students. By using the concept of " latus rectum " in Conics , we can connect "conic sections"-- representation of geometrical aspect, with "the equation of conic sections"-- representation of algebraic aspect to improving insufficiency of text books.

同时本文也试著从历史文本中寻找材料，简单举例说明数学教师可以如何应用这些史料在几何单元教学上，例如三角函数的正余弦定理，最后再以圆锥曲线的正焦弦为例，说明如何利用数学史料於此单元的教学，尤其是阿波罗尼斯的《锥线论》中对圆锥曲线的3个命题，将此3个命题的内容与意涵，尤其是正焦弦在圆锥曲线的几何意义上所扮演的角色，将其适当地融入教学中，将可使学生真正学习圆锥曲线的几何知识，而不再只是代数形式的几何知识。

Based on the information taken from the subcompartmental records a comparison between the actual and normal forests was made and a new point of view was proposed in the article: in the case of cultivating timber-forest which is different in cutover age, age class and growing speed within the range of the whole forest station, the forest age class distribution showing the opposite shape of "J" is of more benefit to keeping the relative stability of all the age class area than the age class distribution of th...

本文在统计森林资源小班档案卡片有关资料的基础上，把现实林分与法正林相比较，用法正林学说来指导全场森林的调查。并提出了一个新的观点：在整个经营单位内，培育不同生长速度，不同主伐年龄，龄级期不同的用材树种，森林的龄级结构呈反"J"形分布此法正分布更有利于维持各龄级面积的相对稳定，并且，年伐量的波动不大，有利于森林的永续利用。

Methods One hundred and six eyes of 56 patients were divided into three groups: mild myopia (-0.50~-3.00 D), moderate myopia (-3.25~-6.00 D) and high myopia (-6.25 D~) based on measurement with autorefractor in cycloplegia and uncycloplegia.

对56例行屈光不正矫正术的患者（106只眼）分别用电脑验光（睫状肌麻痹和非睫状肌麻痹下）、显然验光、Zywave波前像差仪法测量眼屈光不正，并将患者按屈光不正度数分为三组：低度近视组(-0.50~-3.00 D)，中度近视组(-3.25~-6.00 D)，高度近视组(-6.25 D~)。

The several shapes of diamond grains have been observed in SEM: truncated cube, octahedron, truncated cubo-octahedron, twinned cubo-octahedron, twinned regular decahedron and twinned regular icosahedron. Most of diamond grains are octahedron.

用扫描电子显微镜观察到多种外形的金刚石颗粒：截顶立方体、未截顶正八面体、截顶立方八面体、孪晶立方八面体、正十面体和正二十面体的金刚石颗粒。

These factors were normalized and divided into different degrees according to the probability density function of the normal distribution.

在建模过程中，对每个指标进行了正态化转化和正态性检验，并利用正态分布概率密度函数确立了各指标数年一遇的等级标准。

Then the finite element software ANSYS is used to simulate the orthotropic flattened Brazilian disc specimen subjected to diametrical compression, the accuracy of the approximate formula of compression displacement is checked. The formula is further modified with a semi-empirical and semi-analytical approach, and it is shown to have better accuracy than the original formula covering the whole range of orthotropic anisotropic index of rock, the error is less than 6%.

用有限元分析软件ANSYS模拟正交异性岩石的巴西圆盘试样的对径压缩实验；利用有限元分析结果对正交异性平台位移压缩公式进行精度检验，并用半经验半解析的方法，对该公式进行局部的修改，修改后的公式在岩石材料的正交异性指数的整个范围的总体评价上，误差小于6%，具有更好的计算精度。

Built up dimensional reference frame and vector equation of movement model of orthogonal turn-miling.

为了提高数控车铣的编程效率，论述了正交车铣运动的特征，同时通过对正交车铣运动过程的分析，建立了一个描述其运动的空间坐标系，从而建立了正交车铣运动模型的矢量方程。

Then,the tradition manner of crystallization was evaporating and crystalline,but this paper made the other method . The salt-mixture solution of the disodium hydrogen phosphate and the monometallic odium orthophosphate was put in ethanol.

传统的结晶方法是通过加热蒸发结晶，而本文则采用了一种新的结晶方法，在精调后的正磷酸盐混合溶液中加入乙醇，由于正磷酸盐不溶于乙醇，就会使正磷酸盐溶液达到过饱和，再通过搅拌，析出晶体。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。