迎风凹腔与逆向喷流组合热防护系统冷却效果研究

对迎风凹腔与逆向喷流组合热防护系统的冷却效果进行了分析, 研究了相同总压不同流速的逆向喷流对组合结构的流场、气动受力及壁面传热的影响. 通过与相关的实验结果对比, 验证了数值方法的可靠性. 研究发现:该结构能够有效地对飞行器鼻锥表面进行冷却, 引入很小总压的逆向喷流(逆喷总压比 PR=0.1), 组合结构的冷却效果就可以远远优于单一的迎风凹腔; 相同逆向喷流总压下, 逆喷速度越高, 逆喷流量越大, 外壁面的冷却效果越好; 随逆喷流速提高, 气动阻力也进一步减小. 本文研究的组合结构非常适用于     

藤梨根红外光谱聚类分析及可视化鉴别

探索傅里叶变换红外光谱技术在抗癌中药藤梨根快速鉴别、分析方面的应用。对不同品种藤梨根药材的红外光谱图进行了聚类分析和主成分分析,以样品的主成分数值为评价指标,并将谱图进行可视化表达。结果显示,应用傅里叶变换红外光谱法结合主成分分析和谱图的可视化转化,能够实现红外光谱无损快速鉴别藤梨根品种。傅里叶变换红外光谱法的应用能够快速、简便、准确地鉴别藤梨根的品种,是其质量监测一种直观有效的方法。     

Fast calibration methods using cosmic rays for a neutron detection array

An overall irradiation and calibration technique was introduced and applied to a test scintillation detector array. An integral conversion method was used to reduce the nonlinearity of the time difference spectrum, and to improve the position determination especially for positions close to the two ends of a long scintillation bar. An overall position resolution of about 3.0 cm (FWHM) was extracted from the residual analysis method and verified by a direct measurement. Energy calibration was also realized by selecting cosmic rays at different incident angles. The bulk light attenuation lengths for the four test bars were also determined. It is demonstrated that these methods are especially efficient for calibrating large and complex detector arrays.     

Design and construction of endo-functionalized multiferrocenyl hexagons via coordination-driven self-assembly and their electrochemistry

The construction of a new family of endo-functionalized multiferrocenyl hexagons with various sizes via coordination-driven self-assembly is described. The structures of these novel metallacycles, containing several ferrocenyl moieties at their interior surface, are characterized by multinuclear NMR ((31)P and (1)H) spectroscopy, cold-spray ionization mass spectrometry (CSI-TOF-MS), elemental analysis, and molecular modeling. Insight into the structural and electrochemical properties of these endo-functionalized multiferrocenyl hexagons was obtained through cyclic voltammetry investigation.     

Monte Carlo simulation for bremsstrahlung and photoneutron yields in high-energy x-ray radiography

This paper reports on the results of calculations using a Monte Carlo code (MCNP5) to study the properties of photons, electrons and photoneutrons obtained in the converted target and their transportations in x-ray radiography. A comparison between measurements and calculations for bremsstrahlung and photoneutrons is presented. The radiographic rule and the effect of the collimator on the image are studied with the experimental model. The results provide exact parameters for the optimal design of radiographic layout and shielding systems.     

表面活性剂对分散体系粘度影响的特殊性

通过液体石蜡的水基化分散对影响分散体系粘度的粒子大小、表面活性剂胶束和界面膜等因素进行了研究.结果表明,表面活性剂胶束对分散体系粘度的影响极为有限,而在分散相粒子界面上由表面活性剂分子所形成的界面膜是导致分散体系粘度产生变化的重要因素.实验数据表明,对于分散体系的稳定性,存在一个表面活性剂浓度变化的临界值,而该临界值所对应的是表面活性剂分子在粒子表面以最紧密和规整的方式形成的界面膜,该种界面膜使分散体系粘度达到最大值,从而最大限度地保证了分散体系的稳定性.     

3-甲基吡啶在PbO2-SPE组合电极上的电氧化研究

采用热压法制备PbO₂-SPE组合电极,通过循环伏安和稳态极化曲线测量研究了该电极对3-甲基吡啶电氧化反应的活性.考察了阳极液中有、无液相支持电解质和不同阴极液情况下,电流密度与过电位和过电位与槽压的关系.初步研究了利用PbO₂-SPE组合电极在无液相支持电解质的溶液中进行3-甲基吡啶电氧化制取烟酸的可行性,给出了特定条件下的选择性和电流效率.     

Measure Synchronization on Symplectic Map

Measure synchronization in coupled Hamiltonian systems is a novel synchronization phenomenon. The measure synchronization on symplectic map is observed numerically, for identical coupled systems with different parameters. We have found the properties of the characteristic frequency and the amplitude of phase locking in regular motion when the measure synchronization of coupled systems is obtained. The relations between the change of the largest Lyapunov exponent and the course of phase desynchronization are also discussed in coupled systems, some useful results are obtained. A new approach is proposed for describing the measure synchronization of coupled systems numerically, which is advantage in judging the measure synchronization, especially for the coupled systems in nonregular region.     

乳液体系中影响分散相粒子大小及分布的因素——cmcO及cmcW的协同作用

用马尔文MastersizerMicroplus型激光粒度仪对液体石蜡及环氧树脂E-20与甲苯等有机溶剂以不同比例所形成的体系经乳化后的粒子大小及分布进行研究,结果表明,随着油溶性表面活性剂在油相中溶解性的改善,分散相的粒子大小及分布也明显得到改善.cmcO及cmcW的协同作用对获得理想的分散相粒子大小及分布起到了至关重要的作用     

Controlling Strong Chaos by an Aperiodic Perturbation in Area Preserving Maps

We demonstrate a method for controlling strong chaos by an aperiodic perturbation in two-dimensional Hamiltonian systems.The method has the advantages that the controlled system remains conservative property and the selection of the perturbation has a considerable diversity.We illustrate this method with two area preserving maps:the non-monotonic twist map which is a mixed system and the perturbed cat map which exhibits hard chaos.Numerical results show that the strong chaos can be effectively controlled into regular motions,and the final states are always quasiperiodic ones.The method is robust against the presence of weak external noise.