The design of electromagnetic acoustic experimental platform and the study on radiated sound field by its probe

Electromagnetic acoustic testing technology has aroused extensive concern in the field of ultrasonic nondestructive testing due to its advantages of non-contact with the test specimen, couplant free and good signal reproducibility. This article summarizes the related re- search work of our group in recent years and mainly introduces the two parts on electromagnetic acoustic experimental platform and radiated sound field by its probe in detail.     

等光强分布的折平板反射聚光系统的实验研究

基于平板玻璃镜反射聚光获得等光强分布的方法,提出了折平板反射聚光太阳能系统的设计方案。推导了平行光聚光公式,可在给定接收截面宽度、倾角和安装高度时,给出一定聚光比所需的反射板数量、宽度、倾角及坐标位置;建立了CCD法测量能流密度分布的测试平台以及聚光光伏实验装置,并对折平板聚光系统进行了实验研究。结果表明,折平板玻璃镜聚光系统可以得到较为均匀的辐射能流密度,并且系统的发电效率也较高。     

Study of low momentum track reconstruction for the BESⅢ main drift chamber

In order to overcome the difficulty brought by the circling charged tracks with transverse momentum less than 120 MeV in the BESⅢ Main Drift Chamber （MDC）, a specialized method called TCurlFinder was developed. This tracking method focuses on the charged track reconstruction under 120 MeV and possesses a special mechanism to reject background noise hits. The performance of the package has been carefully checked and tuned by both Monte Carlo data and real data. The study shows that this tracking method could obviously enhance the reconstruction efficiency in the low transverse momentum region, providing physics analysis with more and reliable data.     

Secondary electron time detector for mass measurements at CSRe

The Isochronous Mass Spectrometry is a high accurate mass spectrometer. A secondary electrons time detector has been developed and used for mass measurements. Secondary electrons from a thin carbon foil are accelerated by an electric field and deffected 180° by a magnetic field onto a micro-channel plate. The time detector has been tested with alpha particles and a time resolution of 197 ps (FWHM) was obtained in the laboratory. A mass resolution around 8×10-6 for m/m was achieved by using this time detector in a pilot mass measurement experiment.     

Measurement of the total reaction cross section for the mirror nuclei ~(12)N and ~(12)B

The mirror nuclei ~(12)N and ~(12)B are separated by the Radioactive Ion Beam Line in Lanzhou (RIBLL)at HIRFL from the breakup of 78.6 MeV/u ~(14)N on a Be target. The total reaction cross-sections of ~(12)N at 34.9 MeV/u and ~(12)B at 54.4 MeV/u on a Si target have been measured by using the transmission method.Assuming ~(12)N consists of a ~(11)C core plus one halo proton, the excitation function of ~(12)N and ~(12)B on a Si target and a C target were calculated with the Glauber model. It can fit the experimental data very well. The characteristic halo structure for ~(12)N was found with a large diffusion of the protons density distribution.     

High pt and photon physics with ALICE at LHC

ALICE,A Large Ion Collider Experiment,is dedicated to study the QCD matter at extreme high temperature and density to understand the Quark Gluon Plasma (QGP) and phase transition.High-transversemomentum photons and neutral mesons from the initial hard scattering of partons can be measured with ALICE calorimeters,PHOS (PHOton Spectrometer) and EMCAL (ElectroMagnetic CALorimeter).Combing the additional central tracking detectors,the γ-jet and π 0-jet measurements thus can be accessed.These measurements offer us a sensitive tomography probe of the hot-dense medium generated in the heavy ion collisions.In this paper,high p T and photon physics is discussed and the ALICE calorimeters capabilities of high-transverse-momentum neutral mesons and γ-jet measurements are presented.     

Eu2+和Dy3+共掺CaxSr2-xSiO4硅酸盐固溶体发光性质探究

稀土发光材料和固溶体发光材料受到人们的广泛关注,稀土固溶体发光材料本身的结构特性在一定程度上能够影响和决定它的发光特性,而发光特性又直接关系到材料的性能和使用前景.因此,本论文的主要工作时通过改变固溶体发光材料CaxSr2-xSiO4: 0.01Eu2+ , 0.01Dy3+固溶离子Ca和Sr的比例浓度来实现对固溶体发光材料基质结构的调节,测得了不同固溶比例下的样品的激发光谱和部分发射光谱以及热释光谱,并对这些实验结果进行分析.     

Cu-ZnO-CeO2催化剂组成对CO2加H2合成甲醇性能的影响

采用并流沉淀法分别制备了CuO-CeO₂（物质的量比为5：1）、CuO-ZnO（物质的量比为5：4）、CuO-ZnO-CeO₂（物质的量比为5：4：1）三组目标催化剂,通过X射线衍射（XRD）、氢气升温还原（H₂-TPR）、CO₂程序升温脱附（CO₂-TPD）、氮气吸附-脱附、X射线光电子能谱（XPS）、N₂O滴定表征技术对催化剂的物化性能进行了测试,并在高温高压微催化反应器中对催化剂进行活性评价。研究了CuO-ZnO-CeO₂组成对CO₂加氢合成甲醇的影响。结果表明,与二组分催化剂相比较,三组分CuO-ZnO-CeO₂催化剂物化性能及催化活性发生了很大变化,催化剂表面碱性位增强,热稳定性增强,CuO颗粒粒径变小,铜分散度以及氧空位浓度提高,最终催化活性显著提高。其中,CuO-ZnO-CeO₂催化剂中,CuO颗粒粒径为8.2nm,铜的比表面积为68.4m²/g,铜分散度为7.19%,甲醇的选择性和收率分别为48.6%和0.057mmol/（g·min）,催化剂活性较好。     

Electronic and Functional Structure of Copper in Plant Cu/Zn Superoxide Dismutase with Combined Site-directed Mutagenesis and Electron Paramagnetic Resonance

Arabidopsis thaliana copper-zinc superoxide dismutase 1 (AtSOD1) is a typical metalloenzyme conferring cellular protection against the excessive accumulation of toxic reactive oxygen species, and is therefore considered as a critical protein. However, the structure and function of the vital amino acids around the active site of AtSOD1 remain poorly understood. Herein, the coordinated geometry of the catalytic center in AtSOD1 was reconstructed by electron paramagnetic resonance (EPR) technique, and it was found to be composed of copper and four histidine (H) residues using site-directed mutagenesis. Analysis of the mutants showed that H45 and H62 play essential roles in the catalytic reaction, and H119 plays an accessary role in facilitating substrate or proton transfer. The results indicated that the redox change of the Cu ion and the overall enzymatic activity of the protein were sustained by the H45-Cu-H62 core structure. In contrast, the residue H47 showed nearly no effect on the SOD catalytic activity. These data should contribute to a deeper understanding of the catalytic mechanism of the enzyme, and provide a new approach for the effective molecular modification of copper/zinc SODs to facilitate further research in this field.     

新型四氢苯并[4',5']噻吩并[3',2'∶5,6]吡啶并[4,3-d]嘧啶类化合物衍生物的合成及抗肿瘤活性

本文以环己酮为原料,通过氮杂Wittig反应合成了一系列结构新颖的取代四氢苯并噻吩并吡啶并嘧啶衍生物,并采用MTT法考察所合成目标化合物对CNE2、KB、MGC-803、MCF-7和PC3这5种肿瘤细胞的抑制活性。初步的生物活性结果表明,目标化合物对5种肿瘤细胞均有抑制活性,尤其是对胃癌MGC-803细胞展现出了更强的抑制活性。其中3-(4-氟苯基)-2-((4-氟苯基)氨基)-5-甲基-8,9,10,11-四氢苯并[4',5']噻吩并[3',2':5,6]吡啶并[4,3-d]嘧啶-4(3H)-酮[化合物8c,IC_(50)=(0. 9±0. 25)μmol·L~(-1)]对MGC-803的活性最强,是5-氟尿嘧啶[IC_(50)=(18. 4±1. 43)μmol·L~(-1)]的20倍;同时,目标化合物对正常的胃黏膜上皮细胞GES-1没有毒性。四氢苯并[4',5']噻吩并[3',2':5,6]吡啶并[4,3-d]嘧啶类化合物具有良好的抗肿瘤活性,值得进一步深入研究。