正则分布

The results indicate that multiple reflections are favorable to the increase of depth. When the focal position is above the surface, the absorptive intensity on the front decreases, so the cutting depth decreases. When the focal position is below the surface, the position on the front with the maximum power intensity is downward. The intensity distribution is toward the deeper position, the cutting depth increases. But if the negative focal distance is extremely big, the intensity of the deeper position attenuates sharply with the increase of focal radius and light distances, so the depth deceases.

正离焦切割时，前沿吸收的总激光功率密度减小，切割深度减小；负离焦切割时，最大激光功率密度值的位置下移，使得前沿功率密度分布朝着深部推进，切割深度增加，若负离焦量过大，表面光斑直径和光程增加，更深位置的功率密度减小，切割深度减小；随着激光功率增加、切割速度减小，则前沿弯曲程度减小，被激光直接照射的前沿部位增长，前沿吸收激光功率密度增加，切割深度增加。

Let be a sequence of independent and identically distributed random variables,and ,exist ,then,for any value ,.

Corollary 4.1 设相互独立的随机变量有相同的分布，且，存在，则对于任意正整数，有。

As we all know,there is one Simson line at any point on the circumference of triangles,but in this paper, LHP theorem shows that the above conclusion is not correct for any quadrilateral pyramid in three-dimensional space and also during proving LHP theorem,fixed value theorem is proved,at the same time,one guess about the point H and point P on circumscribed sphere of tetrahedron has been concluded.

众所周知，三角形的外接圆周上任一点存在一条 simson 线，而 LHP 定理则指出对于正四面体该结论是不能推广到三维空间上的，并且在论证 LHP 定理的过程中得出了定值定理，同时作为一般四面体的外接球球面上的 H 点、P 点的分布，给出了一个猜想。

Firstly, the normal stress distribution over the 3D slip surface is initially assumed, which is modified by a function with five parameters involved for the rigorous solution, or by a function with four parameters involved for the quasi-rigorous solution.

假定空间滑面上正应力初始分布，对于严格解，用含5个参数的修正函数对其修正；对于准严格解，则采用含4个参数的修正函数。

The effect of zeolites ion-exchanged by transition metals on thermal catalytic cracking reaction is studied. The product distributions of the cracking reactions catalyzed by theβor ZSM-5 zeolites exchanged with transition metals are different from that catalyzed by corresponding Hzeolites, which means the mechanism of cracking reactions has varied. Group Ⅷ metals Fe, Co, Ni and Cu, Zn are shown to be of strong catalytic activity of oxidative dehydrogenation, while Ti and Cr are not of oxidative activity. Catalyzed by zeolites or catalyst containing Ag, conversion of thermal catalytic cracking reactions and the yield of ethylene increase while the yield of propylene does not decrease. Silver can not only promote the formation of carbonium ion, but also convert carbonium ion into free-radical via redox reaction. The weak adsorption of olefins on silver reduces the occurrence of hydrogen transfer and dehydrogenation. As a result, the yield of light olefins is favored by silver in the catalyst.

采用过渡金属交换的分子筛作为催化剂，进行催化热裂解制取乙烯的反应，研究发现，在β沸石分子筛和ZSM-5分子筛中引入过渡金属后，催化热裂解反应的产物分布与相应的氢型分子筛相比有了较大的变化，说明过渡金属的加入对于催化热裂解反应的机理具有影响，Ⅷ族金属如Fe、Co、Ni和第Ⅰ、Ⅱ副族Cu、Zn表现出较强的氧化脱氢活性，产物中氢气、焦炭的产率很高，Ti、Cr则未表现出氧化作用：分子筛及催化剂中引入银后，催化热裂解反应的转化率和乙烯的产率有了提高，丙烯产率没有很大的变化，说明银在催化热裂解反应中能够促进正碳离子的生成，又有可能通过氧化-还原作用部分改变反应机理，促进了自由基的生成，并且由于银对烯烃的吸附很弱，其氢转移反应和脱氢、加氢活性比较低，有利于烯烃产率的提高。

Therewas a significant characteristic of the vertical distribution of soil enzyme activity,the relationship analysis indicated that there was a significant positive relationshipbetween the catalase activity and OM,and total N,and effective P、K,and ex-changible Mg,there was a negative relationship between the catalase activity andBase Situatiou percentage,and Total Contents of Base;the activity of the polyphe-nol oxidase was positively related with OM,and negatively related with total N andexchangible Ca clearly;The urease activity decreased with CPR increasing,and thechange of the former two kinds of soil enzyme actirity was not significantly withCPR increasing,It is possible to be related with maned disturbance frequently.

随着代次增加，有机质和交换性Ca下降明显；土壤的CEC和交换性酸分别下降了8.8—16.1%和6.8—18.5%，因此，其养分总量亦逐代降低，其中有机质下降幅度最大；土壤酶的活性具有明显的垂直分布特征，相关分析表明，过氧化氢酶活性与土壤OM、全N、有效P、K和交换性Mg有极显著的正相关，而与盐基总量、盐基饱和度呈明显的负相关。多酚氧化酶活性与OM呈显著负相关，与全N、交换性Ca有显著相关。脲酶活性则有随连栽代次增加而有下降趋势，前两种酶在代次之间变化不明显，可能与频繁的土壤干扰有关。

Six subwoofers are arranged on the left and right in the front and rear doors and the rear window shelf, while one loudspeaker is located right in the middle of the instrument panel.

6个超低音扬声器分布在前后门和后窗台板的左右侧，另外的一个超低音则安置在仪表板的正中央

Six subwoofers are arranged on the left and right in the front and rear door s and the rear window shelf, while one loudspeaker is located right in the middle of the instrument panel.

6个超低音扬声器分布在前后门和后窗台板的左右侧，另外的一个超低音则安置在仪表板的正中央

Six subwoofers are arranged on the left and right in the front and rear doors and the rear window shelf, while one loudspeaker is locate d right in the middle of the instrument panel.

6个超低音扬声器分布在前后门和后窗台板的左右侧，另外的一个超低音则安置在仪表板的正中央

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。