DIRECT MASS MEASUREMENTS OF EXOTIC NUCLEI IN STORAGE RINGS

Mass measurements of exotic nuclei is a fast, developing field which is essential for basic nuclear physics and a wide range of applications. The method of storage ring mass spectrometry has many advantages: (1) a large amount of nuclides can be simultaneously measured; (2) very short-lived (T-1/2 greater than or similar to 50 mu s) and very rare species (yields down to single ions) can be accessed; (3) nuclides in several atomic charge states can be investigated, (4) half-life measurements can be performed with time-resolved mass spectrometry. In this contribution we concentrate on some recent achievements and future perspectives of the storage ring mass spectrometry.

A high performance Time-of-Flight detector applied to isochronous mass measurement at CSRe

A high performance Time-of-Flight detector has been designed and constructed for isochronous mass spectrometry at the experimental Cooler Storage Ring (CSRe) The detector has been successfully used in an experiment to measure the masses of the N approximate to Z approximate to 33 nuclides near the proton drip-line Of particular interest is the mass of As-65 A maximum detection efficiency of 70% and a time resolution of 118 +/- 8 Ps (FWHM) have been achieved in the experiment The dependence of detection efficiency and signal average pulse height (APH) on atomic number Z has been studied The potential of APH for Z identification has been discussed (C) 2010 Elsevier B V All rights reserved

Magnetic Field Design of the Dipole for Super-FRS at FAIR

The Super-FRS (Super FRagment Separator) is a part of FAIR (Facility for Antiproton and Ion Research), which will be constructed at GSI, Germany by 17 countries. The Super-FRS comprises 24 superferric dipole magnets. The 2D and 3D magnetic field simulations of the prototype magnet are described in this paper. A passive trim slot and four chamfered removable poles are used to satisfy the required field homogeneity which is better than +/-3 x 10(-4) at 1.6 T, 0.8 T and 0.16 T in a wide elliptical useable aperture of 380 mm x 140 mm. Measurement results at various field levels are shown in this paper as well. It can be seen from the comparison of calculation and measurement results that the magnetic designs of the magnet fulfils the requirements.

Experimental Studies on Scramjet Tested in a Freejet Facility

Two different type scramjet models with side-wall compression and top-wall compression inlets have been tested in HPTF (Hypersonic Propulsion Test Facility) under the experimental conditions of Mach number 5.8, total temperature 1700K, total pressure 4.5MPa and mass flow rate 3.5kg/s. The liquid kerosene was used as main fuel for the scramjets. In order to get fast ignition in the combustor, a small amount of hydrogen was used as a pilot. A strut with alternative tail was employed for increasing the compression ratio and for mixing enhancement in the side-wall compression case. Recessed cavities were used as a flameholder for combustion stability. The combustion efficiency was estimated by one dimensional theory. The uniformity of the facility nozzle flow was verified by a scanning pitot rake. The experimental results showed that the kerosene fuel was successfully ignited and stable combustion was achieved for both scramjet models. However the thrusts were still less than the model drags due to the low combustion efficiencies.

A small arc-heated plasma testing facility for thermal protection materials

Experimental research on a 150 kW arc-heated plasma testing facility was conducted. Stable plasma jets with different gas compositions, temperatures and velocities were obtained at chamber pressure between 400 Pa – 100 kPa. Stagnation ablation experiments were conducted on samples of typical super alloys used for thermal protection systems. The microstructure and hardness of alloys before and after ablation were compared.

Temporal-space-transforming pulse-shaping system with a knife-edge apparatus for a high-energy laser facility

For the first time to our knowledge, in a high-energy laser facility with an output energy of 454.37 J, by using a temporal-space-transforming pulse-shaping system with our own design of a knife-edge apparatus, we obtained a quasi-square laser pulse. (c) 2005 Optical Society of America.

生命体能量代谢过程中的电子传递与光合作用中电子传递反应的化学模拟的ESR研究

本文采用电子自旋共振ESR方法，结合运用自旋捕捉技术（Spin Trapping-ESR）和时间分辨手段(TRESR)，针对某些与生命能量代谢体系电子传递及其化学模拟反应的研究相关的几个重要问题(包括高等植物光系统II颗粒内超氧阴离子自由基(O2-)的产生机制、光合作用模型体系电子传递和跨膜电子传递反应动力学、传统中药有效成分提取物抗氧化分子机理与构效关系），从分子设计、实验方法、分子结构理论、反应机理与动力学分析等几个角度进行了较为系统的探索性研究，并获得以下几点新颖的研究成果： 1．光系统II颗粒内光抑制过程中O2-生成的分子机制 (1)．首先，发展了新Spin Trapping-ESR技术，研制一系列性能优良的新型磷酰基取代的吡咯啉类活性氧自旋捕捉剂，并通过对比研究其捕捉性能，证明磷酰基取代的吡咯啉类捕捉剂比常用的DMPO捕捉剂的捕捉能力强、速度快，自由基加合物稳定性高，适合于光系统II体系中活性氧的研究。 (2)．在PSII颗粒的光抑制过程中成功地检测到了O2-，并探讨了影响O2-产生的诸多因素。包括氧分子的浓度、1O2增强剂与淬灭剂、pH值效应、电子传递链阻断剂的影响。首次提出了O2-生成的分子机制：PSII颗粒中产生的O2-是光系统II中反应中心产生的1O2与次级电子受体QA形成的质子化半醌自由基反应的产物。此外，设计了一套化学模拟体系，进一步证明了02-的生成的分子机制。 2. 中国传统性中药的酚类提取物抗氧化剂的抗氧化分子机理与构效关系研究 用理论计算与实验结合的手段，研究了酚类抗氧化剂与02的反应。探讨了酚类抗氧化物的分子结构与其抗氧化活性的构效关系，为评价抗氧化剂的抗氧化能力提供了一定的依据。 3．有关光合作用模型体系电子传递和跨膜电子传递反应动力学的探索性基础研究 (1)．对原有的电子自旋共振谱仪进行改造，自行设计并研制一套时间分辨ESR装置，时间分辨率达到准微秒级。 (2)．利用时间分辨ESR装置，对C60及其环加成衍生物分子间和分子内光诱导电子转移反应的自由基复合过程动力学进行了研究，从分子结构角度分析了影响电荷分离态稳定性的因素。 (3)．初步探讨了TPP／DODAC与HA／DODAC两种单层囊泡间的光诱导电子转移反应，获得了长寿命的电荷分离态，为光合作用模拟提供有价值的模型。 (4)．通过对比研究mes-卟啉Ⅱ／苯醌／CH。OH的化学诱导动态核自旋态极化( CIDNP)和ESR波谱，提出一个激发态苯醌与质子给体间的光诱导氢转移自由基反应新机理。

导电聚合物薄膜修饰电极的电化学ESR研究

本论文侧重用现场及非现场的光谱电化学方法研究导电聚合物的电聚合过程及聚合物薄膜修饰甲极的氧化-还原行为。用现场的ESR电化学研究了二苯胺的电聚合过程；用现场的可见光谱电化学及非现场的低温ESR研究了同多酸及杂多酸掺杂的聚吡咯薄膜的氧化-还原行为，同时对磷铜酸掺杂的聚吡咯薄膜电极的制备方法及聚合物薄膜修饰电极的电催化性能作了较为细致研究。