固体表面菲涅尔阵列产生的声束聚焦的研究

在固体表面上菲涅尔阵列可实现聚焦声束的B扫描。此阵列产生的弹性波场的分析是固体中会聚声束B扫描成像的物理基础.给出此聚焦声场的全面分析,包括:纵波和横波会聚声束的频率扫描特性;纵波声场沿对称轴和在焦面上的分布;在主焦点的频率响应;纵波场的全空间分布以及阵列参数对会聚声场的影响.最后还讨论了横波的分布.     

Microwave Magnetic Properties and Natural Resonance of e-Co Nanoparticles

Owing to the novel crystal structure, ε-Co nanoparticles with an average diameter of 12 nm are synthesized and the microwave magnetic properties of the epoxy resin composite with 50voi% ε-Co particles are measured in the frequency range 0.1-7 GHz. The experimental resonance frequency （4.7 GHz） matches well with the values obtained by the theoretical calculation with the Kittel equation and fitting the experimental permeability dispersion curve via the Landan-Lifshitz equation. Hence the resonance peak is attributed to natural resonance mode. This work is believed to be beneficial for further understanding microwave applications of the novel ε-Co nanoparticles.     

NLO Corrections of HTC Π0 and Π+Π- Pair Production at ILC in TC2 Model

As well known, if the Higgs boson were not observed at LHC, the technicolor model would be the most favorable candidate responsible for the symmetry breaking. To overcome some defects in the previous model, some extended versions have been proposed. In the TC2 model typical signature is existence of heavy H_TC and technipion Π. A direct proof of validity of the model is to produce them at accelerator. Thus we study the production rates of e⁺ e^- → H_TCΠ⁰ and e⁺ e^- → Π⁺ Π^- at ILC in the topcolor-assisted technicolor (TC2) model. In fact, there is a flood of models belonging to new physics, which can result in products withcharacteristics similar to H_TC+Π of the TC2 model. Therefore to distinguish this model from others one may need to investigate some details by calculating the cross section to NLO. We indeed find that the NLO corrections are significant, namely the ratio δ ≡ (σ_NLO- σ_LO)/σ_LO in e⁺ e^- → H_TC Π⁰ exceeds 100% within a plausible parameter space.     

HIRFL-CSR前端总线控制器的改进设计

论述了用于兰州重离子加速器冷却存储环(HIRFL CSR)控制系统的前端总线系统控制器的改进。 改进了控制器的嵌入式操作系统和应用程序, 开发了控制器和数据库交换数据的应用程序。 该控制器基于BGA封装的ARM920T(ARM9)处理器和嵌入式的LINUX操作系统, 可以连接标准的VGA显示器、 键盘、 鼠标, 采用了现场可编程的FPGA器件进行背板接口设计, 并具有64 mA高驱动能力的总线驱动器, 以及拥有灵活的接口信号定义可编程能力, 是HIRFL CSR控制系统的关键部件。 The EVME bus controller which is a key component of the HIRFL CSR control system was improved . Besides reconfiguring the embedded Linux, a utility program was developed for data exchange between the controller and the database. The bus controller is based on ARM920T(ARM9) micro processor which is BGA packaged. The bus controller has the universal interface of VGA display, keyboard, and mouse. The backboard interface logic is programmed in an in system configurable FPGA device. The bus can drive high current up to 64 mA, with the flexibility of the programmable signal definitions. All the improved performance helped the EVME bus controller play a crucial role in HIRFL CSR control system.     

相控声波测井的模拟实验研究

自行设计和制作了两个小型的四阵元相控线阵并进行了指向性测量,通过调节施加于相邻阵元的激励信号的延迟时间,既可以改变相控线阵声波辐射器辐射能量的方向,又可以改变辐射声束主瓣的角宽,测量结果与理论计算结果的一致性良好。分别把自行制作的小型相控线阵声波辐射器和水听器置于充液微型铝质和混凝土模型井中进行了声波测井模型实验。实验结果表明,随着相邻阵元的激励信号的延迟时间的增加,相控线阵的辐射声束指向角不断变大,先后满足滑行纵波临界折射和滑行横渡临界折射条件,先后使充液井孔中的滑行纵波、滑行横波和斯通利波分别得到加强。通过恰当选择相控线阵的阵元间距和声波频率,可以明显增大相控线阵辐射声束的角宽,使其覆盖所有地层的第一临界角的范围,从而无须在井下不断调整辐射声束方向即可实现相控声波连续测井。     

燃煤过程痕量元素动力学机理的研究进展

由于痕量元素在煤中的含量低微、检测困难,加之其原子量一般较大,可能的反应途径多,使得相关的反应机理研究难度极大。本文结合作者的研究成果,介绍了煤燃烧过程中痕量元素化学反应动力学的国内外研究进展,包括痕量元素化学动力学机理的建立;相关的典型实验、计算模拟及其实验验证、动力学机理模型的简化;痕量元素反应动力学机理的完善和发展,包括采用简单碰撞理论、活化络合物理论(亦称过渡态理论,或绝对反应速率理论)对痕量元素化学反应动力学机理的修正;最后指出煤燃烧过程中痕量元素动力学研究的若干方向是: (1)痕量元素反应动力学模型数据库的建立;(2)煤燃烧过程中,主量元素和次量元素的动力学机理的完善; (3)各痕量元素之间动力学研究的开展; (4)实际燃烧过程中痕量元素动力学行为的研究。     

大孔径静态干涉成像光谱仪的信噪比分析

根据大孔径静态干涉成像光谱仪的原理和特点,分析了光辐射能在光学系统内的传输情况,对探测器上接收到的光辐射能信号和噪音信号做了详细的推导,得到了仪器理论信噪比的表达式.在实验上以大口径积分球为辐射源,采集仪器输出的干涉图像,计算得到仪器的实际信噪比曲线,对大孔径静态干涉成像光谱仪的理论信噪比曲线与实际的信噪比曲线做分析比较,结果验证了用推导的论信噪比的表达式来预估仪器信噪比的可行性.     

Thickness determination of molecularly thin lubricant films by angle-dependent X-ray photoelectron spectroscopy

An angle-dependent X-ray photoelectron spectroscopy (XPS) method used to measure the thickness of molecularly thin lubricants was developed. The method was built based on an island model of patched overlayer on a flat substrate by using the photoemission signal solely from the lubricant film. Typical molecularly thin Zdol films on the CHx overcoat of unused commercial magnetic disks were measured to verify the metrology. The lubricant thickness determined by the metrology was equal to the recent result by thermostatic high vacuum atomic force microscopy. The measured deduction in the thickness of the molecularly thin lubricant films, successively irradiated by the monochromatic source operated at 14 kV/250 W, was as low as 1 ? during the first irradiation hour. XPS spectra showed that no hydrocarbons, water or oxygen were adsorbed over the Zdol outer surfaces in the tested XPS conditions. The inelastic mean free path (IMFP) of C 1s in Zdol or in CHx was found to be independent of take off angle (TOA) when TOA < 40°. The IMFP of C 1s in Zdol was ∼63.5 ? and the lubricant island thickness was ∼35 ?.     

13C NMR在新型灵芝三萜类化合物的应用

高等真菌灵芝属的子实体作为著名的中药,灵芝三萜类化合物是中药灵芝主要活性化学成分,近年来灵芝三萜类化合物仍然不断被大量发现, 而且结构越来越新奇. 本文总结了10年来文献报道灵芝三萜化合物的¹³C NMR化学位移,找出了一些规律, 对进行灵芝三萜化合物类结构的研究,将提供十分便捷的途径.     

高温下正十五烷的拉曼光谱研究

文章在金刚石压腔下研究了正十五烷从室温到350℃的拉曼光谱特征.结果表明:随着温度的升高,体系压力也在不断增大;CH3,CH2对称和反对称伸缩振动同时受到温度和压力的影响,但2种作用相反.由于压力效应大于温度效应,随温度压力的增大CH3,CH2对称和反对称伸缩振动的拉曼位移均向高频方向移动,说明C-H键键能在增大.另外,由于新物质的生成导致过强荧光产生而无法测出正十五烷的拉曼光谱,而且过强荧光出现的时间早晚与温度和压力有一定的关系.