皮秒Nd:YAG激光对生物金属纯Ti和Ti–13Nb–13Zr合金的表面改性

The effects of picosecond Nd:YAG laser irradiation on chemical and morphological surface characteristics of the commercially pure titanium and Ti–13Nb–13Zr alloy in air and argon atmospheres were studied under different laser output energy values. During the interaction of laser irradiation with the investigated materials, a part of the energy was absorbed on the target surface, influencing surface modifications. Laser beam interaction with the target surface resulted in various morphological alterations, resulting in crater formation and the presence of microcracks and hydrodynamic structures. Moreover, different chemical changes were induced on the target materials’ surfaces, resulting in the titanium oxide formation in the irradiation-affected area and consequently increasing the irradiation energy absorption. Given the high energy absorption at the site of interaction, the dimensions of the surface damaged area increased. Consequently, surface roughness increased. The appearance of surface oxides also led to the increased material hardness in the surface-modified area. Observed chemical and morphological changes were pronounced after laser irradiation of the Ti–13Nb–13Zr alloy surface.     

竞争环境下的新产品销售模型

本文首先建立在考虑产品使用寿命的情况下，产品销售和数学模型，并对产品的销售状况进行了分析，然后财建立在竞争环境中，进入市场的新产品的前期销售情况的数学模型，并利用微分方程的极限理论对方的解进行了分析。     

Rapid establishment of pure lines of silver carp (Hypophthalmichthys molirix) and bighead carp (Aristichthys nobilis)

The diversity of gynogenetic, artificial sex reversal and natural silver carp and bighead carp is examined using randomly amplified polymorphic DNA (RAPD) method.All of the 187 bands are obtained and 19 (10.16%) of them are polymorphic in gynogenetic silver carp.Meanwhile 32 (15.61%) out of 205 bands are polymorphic in control group.In gynogenetic bighead carp a total of 232 bands are identified and 11 (4.74%) out of them are polymorphic, while 25 (10.37%) out of 241 bands are polymorphic in control group.The genetic distance of four populations is calculated and it is 0.102 and 0.023 for gynogenetic silver carp and gynogenetic bighead carp respectively.The values of natural silver carp and bighead carp are 0.161 and 0.104.From the UPGMA trees constructed based on genetic distance, the sex reversal individuals that match with the gynogenetic female individuals are picked out.A new breeding process of establishing a pure line is developed.     

苎麻纯落麻转杯纺假捻盘磨损研究

本文通过转杯纺在运转条件下加工苎麻纯精梳落麻的磨损试验方法,对表面镀铬及渗硼假捻盘进行了磨损试验。通过观测各假捻盘磨损前后的体积变化以及表面形貌扫描电镜照片,分析了各假捻盘的磨损机理,得出渗硼假捻盘耐磨性优于镀硬铬假捻盘的结论,建议在生产实践过程中对渗硼假捻盘进一步考察应用。     

纯粹型控股公司股权价值评估

以纯粹型控股公司股权价值评估为研究对象，在介绍、比较目前三种公司价值评估技术方法即相对价值评估法、贴现现金流量估价法和期权估价法及其各自特点和适用范围的基础上，提出了运用现金流贴现法中的红利贴现模型评估纯粹型控股公司股权价值的观点，并就如何具体运用红利贴现模型评估纯粹型控股公司股权价值做了详细论述。     

复四元数与狭义Lorentz群

本文研究了复四元数,用以表示狭义Lorentz群,导出了一些有意义的结果。     

网上售票系统方案

B to C是目前电子商务的主要交易模式，介绍了一种基于SET的网上售票系统，这是一种典型的电子商务应用系统．     

句搜明月梨花内趣入春风柳絮中--唐彦谦诗歌及其文学史地位的再认识

唐彦谦生活在晚唐之际,历来被视为李商隐之末流.实际上,他转益多师,自铸伟辞,律绝清新含蓄,悠然远韵;咏史感情深沉,用事精到,绝无晚唐绮艳和衰飒之气,实为晚唐诗坛上的一个特殊存在.     

组合曲梁的径向应力及其对正应力的影响

在纯弯曲组合曲梁正应力公式的基础上，进一步导出了径向应力的计算公式，并对组合曲梁径向应力对弯曲正应力的影响进行了估算，给出了弯曲正应力公式的适用参考范围     

Fe—C相图的形成

本文以纯 Fe 相图为基础,探讨了 Fe—C 相图的形成过程。重点论述了 Fe—Fe_3C相图形成的规律性,并对其形成规律性进行了讨论与分析,从而为进一步理解、应用Fe—Fe_3C 相图奠定了基础。