降香黄檀荚果和种子生长发育规律研究

降香黄檀(Dalbergia odorifera)为珍稀树种,天然分布的降香黄檀濒临绝迹,为保护现有的降香黄檀种质资源,本研究以广西降香黄檀荚果作为研究对象,观察荚果和种子的生长发育变化情况,并对降香黄檀种子部分生理生化指标及发芽率的变化进行测定,探讨降香黄檀荚果和种子的生长发育规律,为确定其适宜采收期提供理论支撑。结果表明：降香黄檀荚果和种子的颜色由浅绿色逐渐过渡到黄褐色,最终在盛花期后160 d后变为深褐色;荚果和种子体积大小在整个采收期中一直维持不断增长的趋势,且在盛花期后185 d开始缓慢而稳定地增长;种子含水量在盛花期后185 d后降至35%左右并趋于稳定;种子可溶性糖含量呈现先升高后降低的趋势,在盛花期后165 d最高,为45 g·kg^-1左右,直至盛花期后195 d降至42 g·kg^-1左右;种子可溶性蛋白含量呈“双峰”动态变化,盛花期后135 d达到第1个峰值,盛花期后180 d达到第2个峰值,之后开始缓慢下降;种子的发芽势、发芽率在盛花期后140-170 d达到最高,且与170 d后无显著性差异。因此,盛花期后185-200...     

TEM observation of oxidation of CuZnAlMnNi shape memory alloy

The atmospheric oxidation of a quenched CuZnAlMnNi alloy after ion-polishing was examined by transmission electron microscopy (TEM). It was found that a lot of oxide grains with various sizes yield homogeneously on the surface of the alloy after exposure at room temperature for 90 d. The grains mainly form along the planes of stacking fault, meanwhile, they can also be observed at the stacking fault tetrahedrals or around the dislocation lines. The formation of the oxides gives rise to the reduction of the stacking faults, and even complete disappearance in some zones, which is partly responsible for the decrement of shape memory effect (SME) of the alloy quenched during long-term holding at room temperature.     

锚喷机分料盘磨损机理

从锚喷机分料盘（俗称衬板）的实际工作情况出发,着重对不同热处理工艺下的试样进行磨损和冲击试验,并借助扫描电镜观察,研究了高铬白口铸铁分料盘的磨损机理;分析其影响磨损的主要因素,最终找出一个硬度和韧性最佳匹配的工艺来提高分料盘使用寿命。     

Carbon nanotubes for supercapacitors:Consideration of cost and chemical vapor deposition techniques

In this topic,we first discussed the requirement and performance of supercapacitors using carbon nanotubes(CNTs) as the electrode,including specific surface area,purity and cost.Then we reviewed the preparation technique of single walled CNTs(SWNTs) in relatively large scale by chemical vapor deposition method.Its catalysis on the decomposition of methane and other carbon source,the reactor type and the process control strategies were discussed.Special focus was concentrated on how to increase the yield,selectivity,and purity of SWNTs and how to inhibit the formation of impurities,including amorphous carbon,multiwalled CNTs and the carbon encapsulated metal particles,since these impurities seriously influenced the performance of SWNTs in supercapacitors.Wish it be helpful to further decrease its product cost and for the commercial use in supercapacitors.     

基于波像差函数建立大口径施密特校正板方程

施密特光学系统由施密特校正板和球面反射镜组成,校正板设置在球面反射镜的球心处,系统的焦点不一定和反射镜的焦点重合。为了得到精确的校正板面形初始结构参数,基于波像差函数建立了带有离焦量的大口径施密特校正板的数学模型,同时校正了系统的三级和五级球差。利用光学设计软件对校正板口径为1000mm、主镜的曲率半径为2000mm、F数为1的系统进行了设计和分析,来验证校正板面形数学模型的正确性。结果显示此校正板的数学模型与优化后结果吻合得较好,校正板面形初始结构参数的精度得到了极大的提高,这为大口径、大相对孔径的施密特光学系统的设计提供了理论基础。     

Excitons and linear optical spectra of E33 and E44 in single wall carbon nanotubes under axial magnetic field

The E₃₃ and E₄₄ optical spectra of semiconducting single-walled carbon nanotubes under axial magnetic field (B) are studied using the tight-binding model, which also takes into account the exciton effect. It is found that the E₃₃ and E₄₄ splitting, induced by the axial magnetic field, is line increased with magnetic field, which can be described by the splitting rate. Also by investigation of the dependence of splitting rate, we found that it shows a clear (2n+m) family behavior besides the diameter dependence, which can be used as a supplemental tool to identify the tubes used in the experiment, and is expected to be detected by the future experiment.     

聚乳酸自支持膜的叠加及其作为药物控释阻隔层的研究

发展了一种将自支持膜层层叠加制备多层膜的新方法,并研究了该薄膜对药物释放的调控效果. 首先利用聚乙烯醇作为牺牲层制备出聚乳酸自支持膜,然后将聚乳酸自支持膜转移或层层叠加到载药薄膜表面,最后对覆盖有聚乳酸薄膜的载药膜进行药物释放研究. 实验结果表明,聚乳酸薄膜对药物的释放起到了明显的调节作用,并且转移的薄膜的控释效果优于原位制备的薄膜,多层叠加的薄膜控释效果强于同等厚度的单层薄膜. 这可能是由于转移和叠加的薄膜层与层之间的空隙对药物的释放起到了缓冲作用所致. 这种基于自支持膜叠加制备多层膜的方法为药物涂层的研究提供了新思路,在生物材料、医用植入器件等领域都有一定的发展前景.     

铁系催化剂上乙苯与CO2氧化脱氢反应

采用浸渍法和溶胶-凝胶法制备了三种含Mg,Fe和Al量相同的Fe2O3-MgO/γ-Al2O3,Fe2O3/MgAl2O4和MgFe0.1Al1.9O4催化剂,在580°C考察了它们催化乙苯与CO2氧化脱氢反应性能,并采用X射线衍射,表面元素分析,H2-程序升温还原和CO2-程序升温脱附等技术对催化剂体相及表面性质进行了表征.结果表明,催化剂制备方法影响Fe物种的存在形态,进而影响催化剂的稳定性和活性.采用浸渍法制备的Fe2O3/MgAl2O4催化剂含有高度分散的Fe2O3活性物种,该物种具有较好的初活性,但是稳定性较差;而采用溶胶-凝胶法制备的MgFe0.1Al1.9O4催化剂中,Fe物种主要以同晶取代的形式存在于尖晶石骨架中,因而具有较高的乙苯与CO2氧化脱氢催化活性和稳定性.     

Effects of vacancy and deformation on an Al atom adsorbed on graphene

First-principles calculations based on density functional theory are carried out to study the adsorption energy of monovacancy and deformation on an Al atom adsorbed on graphene. The bond length and Mulliken charge of an Al atom adsorbed on intrinsic and defected graphene systems are also analyzed. We find that an Al atom, sitting above the H site of intrinsic graphene, is in the most stable location. And the adsorption energy increases with increasing graphene coverage. In 1/32 Al/VC-gra and 1/8 Al/VC-gra Al—C covalent bonds are formed, and the Al—C ionic bonds are enhanced by the vacancy. For our calculations, vacancy and deformation both enhance the adsorption energy of an Al atom adsorbed on a graphene system, but vacancy is more effective. In a tensile system, a geometric distortion is induced in the adsorption structure when the tensile deformation is greater than 15%; in a compression system, the adsorption structure begins to distort from 5%. When the tensile and compressive deformations are greater than 10%, the compressive deformation is more effective than the tension deformation on an Al atom adsorbed on the graphene system. Especially, when the deformation is relatively small, a vacancy has a greater effect on the adsorption energy of an Al atom adsorbed on graphene.     

渤海海洋资源可持续利用研究

通过分析渤海的资源现状,发现造成渤海资源不可持续的主要原因在于人为因素,提出了加大力度治理污染,改善渤海生态环境;在可持续发展层面,从生态原则考虑资源的可持续利用,如土著种及生态位原则、建设海洋牧场原则、休渔期与渔具优化原则、生态补偿原则、公众参与原则,为政府有关部门提供决策参考依据。