An efficient method for mapping the ~(12)C+~(12)C molecular resonances at low energies

The ~(12)C+~(12)C fusion reaction is famous because of its complication of molecular resonances,and it plays an important role in both nuclear structural research and astrophysics. It is extremely difficult to measure the cross sections of ~(12)C+~(12)C fusions at energies of astrophysical relevance because of the very low reaction yields. To measure the complicated resonant structure that exists in this important reaction, an efficient thick target method has been developed and applied for the first time at energies E_(c.m.)5.3 MeV. A scan of the cross sections over a relatively wide range of energies can be carried out using only a single beam energy. The result of measurement at E_(c.m.)=4.1 MeV is compared with results from previous work.This method will be useful for searching for potentially existing resonances of ~(12)C+~(12)C in the energy range 1 MeVE_(c.m.)3 MeV.     

Oxygen-Free Conversion of Methane to Ethylene in a Plasma-Followed-by-Catalyst （PFC） Reactor

Oxygen-free conversion of methane to ethylene was investigated in a two-stage plasma-followed-by-catalyst （PFC） reactor. In the absence of catalyst, pulsed spark discharges and pulsed corona discharges were compared for methane conversion. The results showed that methane was mainly converted to acetylene, but pulsed spark discharges exhibited distinct advantages over the pulsed corona discharges in methane conversion. Thereby, pulsed spark discharges were employed and followed by Ag-Pd/SiO2 catalyst for achieving ethylene as a target product in the PFC reactor. Using the PFC reactor, a steady single-pass ethylene yield of 57% was obtained at a rate of methane conversion of 74%.     

Preparation and characterization of the antifouling porous membranes from poly（vinylidene fluoride）-graft-poly（N-vinyl pyrrolidone） powders

Porous membranes were prepared using the phase inversion method from poly(vinylidene fluoride)-graftpoly(N-vinyl pyrrolidone)(PVDF-g-PVP) powders, which were synthesized via γ-ray induced graft polymerization(pre-irradiation). Chemical compositions, thermal behavior, morphology and hydrophilicity of the membranes were characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, element analysis, thermalgravimetric analysis, differential scanning calorimetry, scanning electron microscopy and contact angle measurements, respectively. Permeation experiments were conducted to evaluate the water flux,and the dynamic BSA fouling resistance performances were investigated, too. All the experimental results indicate that the PVDF-g-PVP membranes demonstrate better separation performances over the pristine PVDF membrane.     

Design of the Control System of Toroidal Field （TF） Power Supply for J-TEXT Tokamak

J-TEXT, formerly TEXT-U at the University of Texas at Austin in USA, is a medium-sized tokamak at the Huazhong University of Science and Technology. The toroidal field （TF） power supply of this tokamak should provide a current of 160 kA and a flat duration of 500 ms for the toroidal field coils to generate a maximum toroidal field of 3 T at the geometric center of the vaccum vessel. This paper presents a design of a new control system which takes the real-time feedback control option for the TF power supply operation. The system was tested successfully during the commissioning. In the first experimental campaign of J-TEXT, the system effectively controlled the power supply to provide a fiat current up to 92.5 kA and therein the TF produced reached 1.74 T, which enabled the machine to generate the first plasma successfully.     

The Development of a Framework for Target Diagnostic Centralized Control System （TDCCS） in ICF Experiments

A framework for target diagnostic centralized control system （TDCCS） in inertial confinement fusion （ICF） experiment has been developed. The developed framework is based on the common object request broker architecture （CORBA） standard and part of the concept from the ICFRoot （a framework based on ROOT for ICF experiments） framework design. This framework is of a component architecture, including a message bus, command executer, status processor, parser and proxy. To test the function of the framework, a simplified prototype of the TDCCS has been developed as well.     

Yield ratio of neutrons to protons in ~(12)C(d,n)~(13)N and ~(12)C(d,p)~(13)C from 0.6 to 3 MeV

The neutron yield in the~(12)C(d,n)~(13)N reaction and the proton yield in the~(12)C(d,p)~(13)C reaction have been measured using deuteron beams of energies 0.6-3 MeV.The deuteron beam is delivered from a 4-MeV electrostatic accelerator and bombarded on a thick carbon target.The neutrons are detected at 0°,24°,and 48°and the protons at135°in the laboratory frame.Further,the ratio of the neutron yield to the proton yield was calculated.This can be used to effectively recognize the resonances.The resonances are found at 1.4 MeV,1.7 MeV,and 2.5 MeV in the~(12)C(d,p)~(13)C reaction,and at 1.6 MeV and 2.7 MeV in the~(12)C(d,n)~(13)N reaction.The proposed method provides a way to reduce systematic uncertainty and helps confirm more resonances in compound nuclei.     

Surface Modification of Polyethylene （PE） Films Using Dielectric Barrier Discharge Plasma at Atmospheric Pressure

Modification of the surface properties of polyethylene （PE） films is studied using air dielectric barrier discharge at atmospheric pressure. The treated samples are examined by Water contact angle measurements, Fourier transform infrared attenuated total reflection spectroscopy （FTIR-ATR）, X-ray photoelectron spectroscopy （XPS） and scanning electron microscopy （SEM）. With the increase in treating time, the water contact angle changes from 93.2° before treatment to a minimum of 53.3° after a treatment for 50 s. Both ATR and XPS results show some oxidized species are introduced into the sample surface by the plasma treatment and the tendency of the water contact angle with the treating time is the same as that of oxygen concentration on the treated sample surface. SEM result shows the surface roughness of PE samples increases with the treatment time increasing.     

SiC Formation Through Interface Reaction between C60 and Si in Plasma Environment

The formation of SiC through the interface reaction between C60 and Si in a plasmaassisted chemical vapour deposition system （PACVD） is investigated with a C60 film previously deposited on Si wafers. The composition and structure of the deposited samples were characterized by micro-Raman spectroscopy and X-ray diffraction （XRD）. The results showed that SiC film was formed successfully in hydrogen plasma at a substrate temperature of 800℃ . The hydrogen atoms in plasma were found to enhance the production of SiC. Furthermore, the effects of the added CH4 on the formation of film were studied. Introduction of CH4 simultaneously with H2 at the beginning would suppress the formation of the initial layer of SiC due to a carbon-rich environment on the substrate, which would be disadvantageous to the further growth of the SiC film.     

^14C标记农药杀螟松和马拉硫磷的制备

以Ｂａ＾１４ＣＯ３为起始原料制得＾１４ＣＨ３ＯＨ，然后和＾１４ＣＨ３ＯＨ与ＰＳＣｌ３在碱性条件下反应，再加入甲基砂基苯酚，在甲基异丁酮溶剂体系下制得＾１４Ｃ－刹螟松，放化纯度〉９５％，放射性比活度为１８８．７ＢＭｑ／ｍｏｌ，＾１４ＣＨ２ＯＨ与Ｐ２Ｓ５合成的中间体，加顺丁烯酸二乙酯在甲苯溶剂体系中反应制成＾１４Ｃ－马拉硫磷，放化纯度〉９５％，放射性比活度为１５６．４ＭＢｑ／ｍｏｌ。     

用~(14)N(d,α_1)~(12)C核反应研究注入氮在纯铁和GCr15钢中的深度分布

本文描述了利用~(14)N(d,a_1)~(12)C核反应测量固体样品表面层内氮原子含量及深度分布的方法。在Si_3N_4标准样品中,所得到的表面处的深度分辨为48nm。利用该分析手段,研究了在不同注入温度条件下,氮离子注入纯铁和GCr15钢的保留量及深度分布的变化情况。     

A New Atmospheric Pressure Microwave Plasma Source （APMPS）

An atmospheric pressure microwave plasma source （APMPS） that can generate a large volume of plasma at an atmospheric pressure has been developed at Tsinghua University. This paper presents the design of this APMPS, the theoretical consideration of microwave plasma ignition and the simulation results, including the distributions of the electric field and power density inside the cavity as well as the accuracy of the simulation results. In addition, a method of producing an atmospheric pressure microwave plasma and some relevant observations of the plasma are also provided. It is expected that this research would be useful for further developing atmospheric pressure microwave plasma sources and expanding the scope of their applications.     

Intermediate Gas Phase of CHa/[Si（CH3）2O]5 Plasma and Its Effect on Structure of SiCOH Film

This paper investigated the radical behaviour of the plasma of a mixture of methane （CH4） and decamethylcyclopentasiloxane （DMCPS） by optical emission spectroscopy. The plasma was generated by electron cyclotron resonance （ECR） discharge and was used for depositing porous SiCOH low dielectric-constant film. In the ECR discharge plasma, CH, H, H2, C2, Si, O and SiO radicals were obtained. The CH, H and C2 radicals were from the dissociation of CH4, while the SiO. Si and O radicals from the dissociation of the Si-O chain. CHx radicals absorbed in the film were thermally unstable and could be removed by annealing. The dissociation of the Si-O chain led to an increase in a ratio of the Si-Ocage to Si-Onetwork. The removed of CHx radicals and the increased Si-Ocage to Si-Onetwork ratio were beneficial for reducing the film density and dielectric constant.     

Density functional theory study of H,C and 0 chemisorption on UN（O01） and （111） surfaces

We performed density functional theory calculations of H, C, and O chemisorption on the UN（001） and （111） surfaces using the generalized gradient approximation （GGA） and the Hubbard U parameter and revised Perdew-Burke-Ernzerhof （RPBE） exchange-correlation functional at non-spin polarized level with the periodic slab model. Chemisorption energies vs. distance of molecules from UN（001） and UN（111） surfaces have been optimized for four symmetrical chemisorption sites, respectively. The results show that the Hollow, N-top, and Hollow adsorption sites are the most stable sites for H, C, and O atoms with chemisorption energies of 13.06, 25.50 and 27.34 kJ/mol for UN（001 ） surface, respectively. From the point of adsorbent （UN（001） and UN（111） surfaces in this paper）, interaction of O with the chemisorbed surface is of the maximum magnitude, then C and H, which are in agreement with electronegativities of individual atoms. For the UN（001） surface, U-N bond lengths change relatively little （〈 9%） as a result of H chemisorption, however C and O chemisorptions result in remarkable changes for U-N bond lengths in interlayer （〉 10%）. Electronic structure calculations indicate that Bridge position is equivalent with Hollow position, and the most stable chemisorption position for H, C, and O atoms are all Bridge （or Hollow） position for the UN（1 11） surface. Calculated electronic density of states （DOSs） demonstrate electronic charge transfer between .9, p orbitals in chemisorbed atoms and U 6d, 5f orbitals.     

从~(12)C In的反应中在线分离和测定~(123)Xe

用70MeV的~(12)C离子轰击天然铟靶产生氙同位素;实验中采用了氦喷嘴快速传输技术同化学分离相结合的方法,满意地从其它反应产物中分离出~(123)Xe。相对化学产额为80.7％、对Cs、Ge和Ga的去污因子均在1×10~3以上,对As的去污因子为2.7×10~2。     

Investigation of the Parallel Flow in the Edge Plasma of EAST

The effects of the E × B drift and ballooning-like transport on the edge plasma in EAST tokamak are investigated with a simplified fluid model. The simulation results show that the E × B drift and ballooning-like transport affect the plasma behavior. When the toroidal field is reversed, at the low field side the density is much larger and temperatures （both electron and ion） are lower, and the profiles of the density and temperatures become more symmetric. With the ballooning-like transport considered, the spatial ballooning-like distribution at the low field side is not very important, but the magnitude affects the ratios of the inner/outer particle flux and energy as well as the E × B drift. At the top of the scrape-off layer, the Mach number exceeding 0.3 for the normal toroidal field and approaching 0.2 for the reversed toroidal field in the simulation are obtained when the drift and ballooning-like transport are included in the model.     

电位滴定法研究~(99)Tc-HMDP和~(99)Tc-HEDP中Tc的氧化态

~(99)Tc-HMDP和~(99)Tc-HEDP溶液是在相应的螫合剂存在下,用过量SnCl_2还原~(99)TcO_4-制得。用标准I_2液对SnCl_2进行了剩余量电位滴定,确定了在pH～3的介质中,~(99)Tc-HMDP和~(99)Tc-HE-DP中~(99)Tc的氧化态均为+4。全部实验在N_2气流中进行。~(99)Tc-HMDP和~(99)Tc-HEDP的紫外光谱表明:在用I_2滴定的过程中,~(99)Tc只处于一种氧化态+4;将它们放置在空气中,一小时后仍较稳定。     

Effect of Implantation Machine Parameters on N^＋ ion Implantation for Upland Cotton（Gossypium hirsutum L.）Pollen

Effect of parameters of ion implantation machine, including ion energy, total dose, dose rate, impulse energy and implantation interval on the pollen grains of upland cotton implanted with nitrogen ion beam were studied. The best parameters were screened out. The results also showed that the vacuum condition before the nitrogen ion implantation does not affect the pollen viability.     

Study on the Property Evolution of Atmospheric Pressure Plasma Jets in Helium简

Nowadays atmospheric pressure plasma jets （APPJs） are being widely applied to many fields and have received growing interests from cold plasma community. A helium APPJ with co-axial double ring electrode configuration is driven by an AC high voltage power with an adjustable frequency of 1-60 kHz. Experiments are conducted for acquiring the electrical and optical properties of APPJ, including the discharge mode, current peak＇s phase and APPJ＇s length, etc. Moreover, the actions of Penning effect on APPJ are discussed by adding impurity nitrogen into highly pure helium. The results may contribute to further research and aPPlications of APPJs.     

^14C—尿素呼气试验临床应用研究

为探索＾１４Ｃ－尿素呼气试验诊断幽门螺旋杆菌的临床实用价值,选用临床患７０例,２天内同时进行胃镜检查（取胃窦粘膜作病理切片和快速尿素酶试验）和＾１４Ｃ－尿素呼气试验（部分患同时作Ｈｐ－ＩｇＧ或ＤＮＡＨｐ试验）,病理切片和尿素酶试验双阳性为标准阳性对照,双阴性为标准阴性对照。结果表明,＾１４Ｃ－尿素呼气试验灵敏度９３．２％,特异性７３．１％,与对照标准比较差异不显（ｘ＾２＝０．９＜ｘ＾２０．０