CNC车床的故障概率模型

本文从ＣＮＣ车床的故障数据的采集入手,建立了ＣＮＣ车床的故障数据库。应用模糊综合评价的方法对ＣＮＣ车床的故障模型进行了分析     

Nd:YAG激光对咽部疾病治疗的独特疗效

目的 :探讨Nd :YAG激光对咽部疾病的治疗疗效。方法 :对我院 2 0 0 0年 1月 -2 0 0 3年 3月间Nd :YAG激光治疗的咽部病变 85 3例进行回顾性分析 ,并对激光与药物、手术等治疗方法分析。结果 :咽炎 (增生型 )激光治疗可以达到 95 %的治愈率 ,对扁桃体炎或上感所致的发热可以通过激光扁桃体照射、漂白达到一次性热退 ,对于扁桃体术后所致的特殊原因出血 ,用药物及手术无法解决的 ,可以用激光治疗 ,特别是对扁桃体肿大所致鼾症及扁桃体炎并发症 ,更具有使病人痛苦小、经济、疗效快、治愈率高的独特优点     

基于微悬臂梁生物传感器检测三磷酸腺苷

基于适配子构建了无标记检测三磷酸腺苷(ATP)的微悬臂梁生物传感器。 将ATP适配子修饰在微悬臂梁阵列中的传感悬臂镀金面上,用来识别ATP,而参比悬臂修饰巯基己醇(MCH)防止非特异性吸附。 ATP与其适配子发生特异性相互作用,使悬臂的上下两个表面产生应力差,导致传感悬臂产生偏转,扣除参比悬臂偏转后其偏转值与ATP的浓度在0.5~5 mmol/L范围内有良好的线性关系,相关系数为0.998,最低检出限为0.06 mmol/L。 该微悬臂梁生物传感器响应快速、操作简单,并且对ATP具有良好的特异性。     

双用户2.5 Gb/s 100 km光码分多址传输实验

稳定性高、低成本的窄脉冲光源、高性能编解码器和具有旁瓣/噪声抑制功能的接收机是光码分多址系统实用化的3个关键模块.实验中利用增益开关脉冲光源和63 chip等效相移超结构布拉格光纤光栅相位编解码器的半边带应用,判决门限调整与宽带判决相结合的接收机实现了双用户、2.5 Gb/s 100 km传输.实验中测量了误码率与判决时刻和判决门限的关系曲线,系统在10 ps的判决时刻容限内和17%的幅度判决容限内实现了无误码传输.     

The study of novel Fe3O4@γ-Fe2O3 core/shell nanomaterials with improved properties

The surface structure of the iron oxide nanoparticles obtained by the co-precipitation method has been investigated, and a thin layer of α-FeOOH absorbed on surface of the nanoparticle is confirmed by analyses of Fourier transform infrared (FTIR), X-ray photoelectron spectra (XPS) and surface photovoltage spectroscopy (SPS). After annealed at 400 °C, the α-FeOOH can be converted to γ-Fe₂O₃. The simple-annealed procedure resulted in the formation of Fe₃O₄@γ-Fe₂O₃ core/shell structure with improved stability and a higher magnetic saturation value, and also the simple method can be used to obtain core/shell structure in other similar system.     

聚甲基丙烯酸甲酯电泳芯片电化学检测氨基酸

采用集成铜微电极的聚甲基丙烯酸甲酯(PMMA)电泳芯片,实现对氨基酸的分离与检测。考察了制备的铜微电极对氨基酸的催化活性以及检测电位和分离场强对分离效果的影响。在优化条件(30mmol／L NaOH缓冲溶液中,检测电位为0．7V(vs.Ag／AgCl),进样与分离电场强度均为50V／cm)下,用3cm长的通道实现了精氨酸(Arg)与亮氨酸(Leu)的分离。     

Y2O3:Ho/Yb纳米晶的上转换发光性质

采用燃烧法制备了不同尺寸和不同掺杂浓度的Y2O3：Ho／Yb纳米晶,并系统地研究了颗粒尺寸对Y2O3：Ho／Yb纳米晶发光性质的影响。研究发现,随着尺寸的减小,发射强度和荧光分支比均发生了显著变化,Ho^3 的整体发射强度降低,但5^F5→^5I8的红光发射比^5S2(^5F4)→^5I8的绿光发射的荧光分支比增强。尺寸减小,表面原子更易吸附空气中的水和二氧化碳,引入一些较大的振动模式,从而增大了无辐射跃迁的速率,荧光分支比随尺寸的变化被归因于表面效应引起的无辐射弛豫过程^5S2(^5F4)→^5F5和^5I6→^5I7的增强。     

单分散磁性纳米粒子靶向药物载体

本文综述了单分散磁性氧化铁纳米粒子的主要制备方法、表面修饰以及在生物医学靶向药物方面的应用研究进展。金属有机前驱体高温热分解法、溶剂热合成法和LSS（liquid-solid-solution）法是目前制备高质量单分散磁性纳米粒子比较有效的手段。通过表面修饰制备出的具有良好水溶性、生物相容性和活性功能基团的磁靶向药物载体将可能实现定位蓄积、高效载药、控制释药和可生物降解等靶向治疗癌症的目的。开发出具有荧光检测、主动靶向识别、高效载药、智能控药释放、无毒副作用和生物相容性于一体的多功能靶向药物载体将是其发展趋势。     

Synthesis of magnetic nickel spinel ferrite nanospheres by a reverse emulsion-assisted hydrothermal process

Nickel ferrite nanospheres were successfully synthesized by a reverse emulsion-assisted hydrothermal method. The reverse emulsion was composed of water, cetyltrimethyl ammonium bromide, polyoxyethylene(10)nonyl phenyl ether, iso-amyl alcohol and hexane. During the hydrothermal process, β-FeO(OH) and Ni_0.75Fe_0.25(CO₃)_0.125(OH)₂·0.38H₂O (INCHH) nanorods formed first and then transformed into nickel spinel ferrite nanospheres. The phase transformation mechanism is proposed based on the results of X-ray powder diffraction, transmission electron microscopy and energy-dispersive X-ray spectroscopy, etc. Nickel ferrite may form at the end of the INCHH nanorods or from the solution accompanied by the dissolution of β-FeO(OH) and INCHH nanorods. The X-ray photoelectron spectroscopy analysis shows that a few Fe³⁺ ions have been reduced to Fe²⁺ ions during the formation of nickel ferrite. The maximum magnetization of the nickel ferrite nanospheres obtained after hydrothermal reaction for 30 h is 55.01 emu/g, which is close to that of bulk NiFe₂O₄.     

Synthesis and Self-assembling of Coumarin-based Low-molecular Weight Organogelators

Four coumarin derivatives(4a―4d) with different alkoxy chains were synthesized. It was found that compound 4d showed a better gelation ability than the other compounds, for example, it could self-assemble into organogels in various organic fluids via ultrasound treatment or heating-cooling process, whereas compound 4c could only gel in a few mixed solvents and compounds 4a, 4b could not form organogel. The results from fluorescent and FT-IR spectra indicate that π-π interaction had an effect on the formatio...