用液压测功的研究

本文介绍了一种测定发动机输出功率的方法。     

Peristaltic transport in a slip flow

Continuum-mechanic derivation of the entrainment of rarefied gases induced by a surface wave along walls (or peristaltic transport) in a confined parallel-plane microchannel is conducted by the perturbation method. Both no-slip and slip flow cases are investigated with the former ones matched with the previous approach by Fung and Yih. Critical reflux values due to first order slip-flow effects become trivial for the free pumping case, and decrease due to second order slip-flow effects after we compared them with no-slip cases. Received 27 August 1999 and Received in final form 10 January 2000     

静压触媒法人造金刚石晶体表面微形貌研究

通过对六面顶压机和两面顶压机生产的静压触媒法人造金刚石晶体表面微形貌图案的研究,发现了人造金刚石晶体表面的胞状图案和枝蔓状+胞状+层状的组合图案.对这些形貌研究表明,这类人造金刚石晶体是在远离平衡的条件下快速长成的.     

First Total Synthesis of (-)-4-O-(6'-Hydroxy-7'(9')-Dehydro-6',7,-Dihydrogeranyl)-Coniferyl Alcohol

Some Ligularia species have long used as folk remedies due to their antibiotic, antiphlogistic and antitumor activities.¹ Compound 1,² a novel coniferyl alcohol, was isolated from ligularia duciformis(Compoitae). The geometrical structure of 1,determined by spectroscopic techniques, was corresponded to 4-o-(6,-hydroxy-7'(9')-dehydro-6',7'-dihydrogeranyl)-coniferyl alcohol. But its absolute configuration at C-₆,has not yet been determined. Herein, we report the total synthesis of (6'S)-(-)-1 from Geraniol 2 through 9 steps (Scheme 1).     

Analysis for the Data of Singly Strange Particle Production in 200AGeVpp,pS and SS Reactions

We have used the event generator LUCIAE to analyse the data of singly strange particle production in pp,pS,and SS reactions at 200AGeV.The results seem to indicate that in comparing with the pp and the pS minimum bias event,the SS center collision seems having stronger final state interaction,shorter fomation time of strange particles,and larger s quark pair suppression factor.The strangeness enhancement evidence from pp to pS and to SS could be explained without the introduction of quark-gluon plasma formation.     

银莲花素晶体结构的精测

银莲花素,C₁₀H₈O₄,是无色透明晶体,属正交晶系,空间群D_2h¹⁵-P2₁/b2₁/c2₁/a,晶胞参数:a=11.063(4),b=11.633(4),c=13.873(4)Å,Z=8。实验结果表明化合物中两不饱和γ-内酯是以螺环形式与环丁烷相连,与光谱结果一致。     

激光测微法研究双(对甲苯磺酸)-2,4-已二炔-1,6-二醇酯的固态热聚合

用激光测微法跟踪了双(对甲苯磺酸)-2,4-己二炔-1,6-二醇酯(TS)固态晶相热聚合时宏观尺寸的变化,由此推算TS聚合时晶胞参数的变化。结果表明,在形成聚合物PTS大分子链的c轴方向上一直收缩,而在横向a、b方向上则是先膨胀后收缩。     

偏心椭圆高斯光束

在椭圆高斯光束横坐标中引入复数偏移量,将其推广为偏心椭圆高斯光束。在垂直于ｚ轴截面内强度分布仍然是椭圆高斯函数分布,在传播方向上光束峰值强度沿直线分布,波前也存在横向位移。对偏心椭圆高斯光束经一阶光学系统的变换关系进行了定量推导。对传播方向偏离ｚ轴的椭圆高斯光束经薄透镜传播时的特例进行了讨论。     

Dynamical cryptography based on synchronised chaotic systems

Recently, a novel dynamical data encryption system based on synchronised chaotic systems was proposed for security communication. Based on the same synchronised chaotic systems, its dynamical cryptography is investigated. In this system, the ciphertext of each bit is mapped to one of two distinct chaotic dynamical equations. The ciphertext can be decrypted by its synchronised chaotic equation. This method can prevent intruders from recovering the information signals by statistical methods. To demonstrate its effectiveness, a 2 bit dynamical data cryptosystem based entirely on the Lorenz system is presented     

Microstructure and corrosion resistance of room-temperature RF sputtered Ta2O5 thin films

The connection between the chemical corrosion resistance and the microstructure of the Ta₂O₅ thin films prepared at room temperature by a RF magnetron sputtering technique on Si substrates has been investigated. We find that the microstructure of the films changes with different RF sputtering power, and is responsible for the degradation of the corrosion resistance in HF solutions. The deposited films are amorphous and porous when the RF power is low. A preferred orientation toward (200) β-Ta₂O₅ can be observed when the RF power is increased to 150 W. In addition, the films deposited under this condition are dense and are consequently more resistant to the attack of chemicals. AT an RF power of 300 W the corrosion resistance of the films declines due to an increase of the exposed pore surface to the HF solution.