α-蒎烯催化加氢反应的研究

以FYX - 2G型高压搅拌釜为加氢反应器 ,测定了在不同搅拌器型式和搅拌转速下高压釜的持气量和反应效果 ,认识到α 蒎烯催化加氢是外扩散控制的反应 ,当搅拌转速为 6 0 0r/min时 ,基本上能消除外扩散的影响。考察了Raney镍和Pd/C催化剂、反应温度在 35 3～ 499K ,压力在 4 0～ 10MPa的条件下对α 蒎烯加氢转化率和选择性的影响 ,结果表明Raney镍更适宜于α 蒎烯催化加氢 ,其转化率随温度、压力增加而提高 ,但选择性下降。采用温度 35 3～ 433K、压力 4 0～ 7 0MPa的操作序列 ,克服了α 蒎烯加氢转化率与选择性互为逆向的缺点 ,缩短了反应时间 ,制得了顺反比高达 18 2∶1的蒎烷 ,并且发现加氢反应从温度 433K开始有副产物对烷生成 ,当温度超过 45 6K时 ,加氢过程还出现飞温现象。     

RBF网络及其在卫星姿态控制中的应用

提出了一种基于RBF网络扰动力矩补偿的控制技术，通过在传统PID控制的基础上，引入RBF网络补偿环节，进一步抑制了扰动力矩的影响，提高了卫星姿态控制精度，首先给出了RBF网络的学习算法，然后根据全补偿原则设计了神经网络补偿姿态控制方案，最后结合某型卫星的姿态控制系统设计实例，进行了数学仿真，结果表明：有RBF网络补偿的系统，姿态的稳态精度得到了明显的改善。     

合成氨扩能改造中锅炉存在的问题及采取的措施

针对天脊集团年产30万t合成氨扩能改造,给2台225t/h高压锅炉带来的除氧器热量过剩、锅炉给水温度升高、主蒸汽温度降低等一系列问题,分析了产生问题的原因,从节约能源、提高锅炉效率考虑,提出了相应的解决问题的办法:利用热量分流、改造省煤器管、增加二级过热器受热面积。经过3年多的生产实践证明,取得了良好的效果。     

Grain Growth Behavior of 5Cr21Mn9Ni4N Steel Micro-Alloyed by Rare Earth

Grain growth behavior of 5Cr21Mn9Ni4NRE steel was experimentally studied at various solid solution treatment temperatures and holding for different times. The experimental results show that the 5Cr21Mn9Ni4NRE steel has the feature of sharp austenite grain coarsening after solid solution treatment at the temperature above 1150 ℃. RE added in the steel has the benefit to restrain grain growth and increase grain growth activation energy.     

SU-8 3D microoptic components fabricated by inclined UV lithography in water

Out-of-plane microlenses and microoptical fiber holder are two of the most important components for building an integrated microoptic system with a precise alignment accuracy. In this paper, a simple and convenient method to fabricate these components from SU-8 by using inclined UV lithography in water is proposed. It consists of two perpendicular exposures in SU-8 at ±45°. DI water possesses a low absorption coefficient and a moderate and stable value of refractive index in near UV. Using water, the exposure angle in SU-8 can be increased to 50° from 35° in air necessary to pattern the desired 45° slope of the sidewalls. The principle of the proposed technique and the detailed fabrication process of the microoptic components will be presented. The integratability of the fabricated components was demonstrated by the fabrication of the microoptical fiber holder with a pre-aligned out-of-plane microlens.     

Local residence time,residence revolution,and residence volume distributions in twin‐screw extruders

This work was aimed at studying the overall, partial, and local residence time distributions (RTD); overall, partial and local residence revolution distributions (RRD) and overall, partial and local residence volume distributions (RVD) in a co‐rotating twin screw extruder, on the one hand; and establishing the relationships among them, on the other hand. Emphasis was placed on the effects of the type and geometry of mixing elements (a gear block and various types of kneading elements differing in staggering angle) and process parameters on the RTD, RRD and RVD. The overall and partial RTD were directly measured in‐line during the extrusion process and the local ones were calculated by deconvolution based on a statistical theory. The local RTD allowed comparing the mixing performance of mixing elements. Also it was confirmed both experimentally and theoretically that specific throughput, defined as a ratio of throughput (Q) over screw speed (N), controlled all the above three types of residence distributions, be they local, partial or overall. The RRD and RVD do not provide more information on an extrusion process than the corresponding RTD. Rather they are different ways of representing the same phenomena. POLYM. ENG. SCI., 48:19–28, 2008. © 2007 Society of Plastics Engineers     

Hydrothermal Reaction Mechanism and Pathway for the Formation of K2Ti6O13 Nanowires

Calculations and detailed first principle and thermodynamic analyses have been performed to understand the formation mechanism of K₂Ti₆O₁₃ nanowires (NWs) by a hydrothermal reaction between bulk Na₂Ti₃O₇ crystals and a KOH solution. It is found that direct ion exchange between K⁺ and Na⁺ plus H⁺ interactions with [TiO₆] octahedra in Na₂Ti₃O₇ promote the formation of an intermediate H₂K₂Ti₆O₁₄ phase. The large lattice mismatch between this intermediate phase and the bulk Na₂Ti₃O₇ structure, and the large energy reduction associated with the formation of this intermediate phase, drive the splitting of the bulk crystal into H₂K₂Ti₆O₁₄ NWs. However, these NWs are not stable because of large [TiO₆] octahedra distortion and are subject to a dehydration process, which results in uniform K₂Ti₆O₁₃ NWs with narrowly distributed diameters of around 10 nm.     

木玩世家锻造品牌之路

4月广州，春暖花开。先后召开的广州国际玩具及礼品展和广州春交会，让花城沸腾了。在这盛会上，一位年仅29岁的浙江商人和他的300多款精美的木制玩具格外引人注目，订单接踵而至。     

Armlets and balanced multiwavelets: flipping filter construction

In the scalar-valued setting, it is well-known that the two-scale sequences {q/sub k/} of Daubechies orthogonal wavelets can be given explicitly by the two-scale sequences {p/sub k/} of their corresponding orthogonal scaling functions, such as q/sub k/=(-1)/sup k/p/sub 1-k/. However, due to the noncommutativity of matrix multiplication, there is little such development in the multiwavelet literature to express the two-scale matrix sequence {Q/sub k/} of an orthogonal multiwavelet in terms of the two-scale matrix sequence {P/sub k/} of its corresponding scaling function vector. This paper, in part, is devoted to this study for the setting of orthogonal multiwavelets of dimension r=2. In particular, the two lowpass filters are flipping filters, whereas the two highpass filters are linear phase. These results will be applied to constructing both a family of the most recently introduced notion of armlet of order n and a family of n-balanced orthogonal multiwavelets.     

八种新功能晶体的比热及其与相变掺杂物关系的实验研究

本文对八种新型功能晶体Ｌｉ２Ｂ４Ｏ７、Ｂｉ１２ＴｉＯ２０、Ｂｉ１２ＧｅＯ２０、Ｂｉ１２ＧｅＯ２０、Ｂｉ４Ｇｅ３Ｏ１２、Ｓｒ１－ｘＢａｘＮｂ２Ｏ６（ｘ＝０．３３，０．４８）、ＬｉＴａＯ３等在１３０～９７３Ｋ范围内的比热行为及其与相变、组分之间的关系进行了实验研究，给出了比热的多项式拟合方程，并与用纽曼－卡普定律及用Ｗｉｋｅｌｍａｎｎ经验方程的比热计算值作了对比，为晶体比热的估算提供了依据和方法。