查询词典 BN

If the power series ∑anxn an ∑anxn and ∑bnxn satisfy the condition r =∑bn xn, we obtain the twin combinatorial identity theorem between the sequences {an} and bn}.We also obtain some specific twin combinatorial identities by using the expansion on the binomial expression formula, including two expansions of combinatorial number(rsn and ...

如果幂级数∑anxn与∑bnxn满足条件r＝∑bnxn 时，获得数列｛an｝与｛bn｝之间孪生组合恒等式的定理，应用在二项式定理等展开式上得出具体的多组孪生组合恒等式，其中包含组合数的两种展开法，Bernoulli数直接表达式的新证等结果。

Wherever you are in the world, you can enjoy standardized professional services of BN.

BN，无论您身在世界的哪个地方，都能享受到BN在中国的专业化、标准化的服务。

In Chapter 1,we investigate BN-pairs of classical groups over local rings.We construct the BN-pairs arising from classical groups of linear,orthogonal and symplectic type over local rings.

本文主要研究局部环上典型群的BN-对，二面体群的BN-对和不变式环，有限域上典型群的极大子群和根子群的有理不变式域的结构。

Furthermore,we consider the relations between the general linear groups and the corresponding BN-pairs and show that they satisfy a commutative diagram of groups.In Chapter 2,we study the structure of unitary groups over finite group rings R and its applications.

第一章考虑任意局部环上典型群的BN-对问题，构造了局部环上一般线性群、辛群、正交群的BN-对，并且证明了局部环上一般线性群与对应的BN-对之间满足群交换图关系。

By analyzing the educt and oxide of 〓 powder and BN powder, it is foundthat residual inside the composite is the main cause for the deliquescence of thecomposite and that the boron oxide mainly comes from the BN.

添加烧结助剂，既有效地促进了样品中导电网络的构成，又对〓-BN复相导电陶瓷的电阻率产生很大影响，而且〓配比越接近渗流阀值，烧结助剂的影响越大。

The educt is boricacid on the surface of the composite, it is believed that oxide reaction takes placeduring the sintering of 〓-BN composite, and part of oxide outgrowth -〓has been left in the sintering body.

通过分析〓-BN复相导电陶瓷表面析出物及〓粉和BN粉的氧化产物，揭示〓-BN复相导电陶瓷中残留的氧化产物——氧化硼是〓-BN复相导电陶瓷引起潮解的主要原因。

H-BN thin films were prepared on the (100)-oriented surface of n-Si by r. f. sputtering physical vapor deposition. The field emission characteristics of the BN films were measured in a ultra high vacuum system. It has been found that the field emission characteristics of BN films is affected evidently by substrates temperature.

利用射频磁控溅射方法，真空室中充入高纯N2(99.99%)和高纯Ar(99.99%)的混合气体，在n型(100)Si基底上沈积了六角氮化硼薄膜，在超高真空0^(-7Pa系统中测量了BN薄膜的场发射特性，发现沈积时基底温度对BN薄膜的场发射特性有很大影响。

With temperature increasing, granular outshoot prefer to grow along with vertical direction of surface of BN core, as well as the wrapped leaf-like shape form from granular ones. And the productions always kept complete morphology of sphere, which was due to the uniform growth of fluffy film on the BN core. Wrapped leaf-like structure of BN piece in fluffy film favored increasement of measured surface area and elimination of oxygen element.

凝并在球核表面的中间产物受到初始BN球核在空间上的诱导作用，随着温度的升高，突出物倾向沿着垂直于球面的方向向外生长，形貌由普通的粒状转变为卷叶状；绒膜的厚度均匀一致，产品得以保持规整的球状形貌，绒膜中卷叶状的BN结构利于氧杂元素的脱除，同时增加了比表面积。

The effects of BN content on the thermal conductivity, hardness and microstructure of AlN-BN composite ceramics prepared by ceramic injection molding and pressureless sintering, as well as the rheological characteristics of the mixtures were discussed.

采用粉末注射成形和无压烧结相结合的工艺制备AlN-BN复相陶瓷，讨论了AlN-BN混合料的流变性能以及BN含量对复相陶瓷热导率、硬度以及显微组织的影响。

The result shows that B combines with N prior to Al at high temperature and brings about coarse particles of BN (about 900 nm), which effectively reduces the amount of fine and dispersive AlN particles, and BN precipitate clinging to MnS precipitation coarsens MnS particles, the pinning of austenite grain boundary is alleviated and the grain growth of ferrite is suppressed.

结果表明高温时B优先于Al与N结合生成粗大的BN粒子(约900 nm)，有效降低了热轧过程细小而弥散的AlN析出量，同时BN依附MnS析出而粗化MnS粒子，减弱了细小弥散析出粒子对奥氏体晶界钉扎以及相变后铁素体晶粒长大的抑制作用。

Chrysanthemum of 10 thousand birthday is lax to edaphic requirement, with the arenaceous qualitative loam with fecund, good drainage had better.

万寿菊对土壤要求不严，以肥沃。排水良好的砂质壤土为好。

He unstepped the mast and furled the sail and tied it.

他拔下桅杆，把帆卷起，系住。