最新刊期
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- 摘要：The front end of the diagnostic beamline in Hefei Light Source (HLS) was introduced. Both software and hardware of the vacuum monitor and control system of the diagnostic beamline were designed. The high stability has been realized with the applications of the CPLD & RF card, and the system has a friendly operation interface due to the use of Human-Machine Interface (HMI).关键词：Diagnostic beamline;CPLD;RF card;HMI (Human-Machine Interface)
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发布时间：2021-03-12 - 摘要：This paper describes two types of pulsed power supplies for the SSRF injection system which is based on solid-state switches. One is a 1.7kV, 10kA septum pulser, while the other is a 7.8 kV, 3.7kA kicker pulser. The charg- ing power supply, discharging switch, structure of the discharging circuit, and feed-back of current are discussed. The prototypes and the simulation show that the stability of the current magnitude is better than ±0.1% and other main targets reach the design requirement.关键词：Solid-state switch;Pulsed power supply;High stability
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发布时间：2021-03-12 - 摘要：In the present work, the M?ssbauer effect was used to study the chemical species of iron element con- tained in aerosol particle PM10 and PM2.5 samples collected at Wusong, Nanhui and People’s Square, the three repre- sent active districts of Shanghai. The results show that the main chemical species of iron were α-Fe2O3, Fe3O4, ferric sulfate and some α-FeOOH.关键词：Airborne particulate matter;Speciation;M?ssbauer spectroscopy;Superparamagnetic particulates
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发布时间：2021-03-12 - 摘要：The REE and trace elements contents in the basalt of the west Zhunger Hongguleleng ophiolite have been measured with INAA method. The geochemical characteristics have been analyzed according to the amounts of its rare earth elements, transition metal trace elements and incompatible elements. The Hongguleleng basalt could be di- vided into two groups: one mainly consists of the basalt which is correlative with the formation of the Hongguleleng ophiolite, including some diabase and trachybasalt, while the other mainly consists of the wall rock basalt which is not correlative with the formation of the Hongguleleng ophiolite. It is significant to research this two types of basalt for studying their formation class, origin characteristics, relative dependence, evolvement procedure and the rule of coming into mine.关键词：NAA;Basalt;REE;Trace element
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发布时间：2021-03-12 - 摘要：In order to measure electric field distribution which is a very important parameter for the tuning of accel- erating cavities, Accelerator Lab of Tsinghua University has developed two measurement systems of longitudinal electric field distribution based on two different kinds of network analyzers. In designing the systems, Visual Engi- neering Environment (VEE), a programming language, is used, and a new technology called Virtual Instruments is in- troduced. Direct I/O is a function module in VEE, and by adopting it to read from and write to instruments, there is no need to take care of bottom protocols, thus decreasing designers’ workload. The systems provide a friendly interfaces for users, demand less from users, and bring in more efficiency and stability.关键词：Longitudinal electric field distribution measurement systems;VEE;Virtual instruments technology;Direct I/O
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发布时间：2021-03-12 - 摘要：It is vital for sustainable development of groundwater resource to understand the groundwater renewal rate in the piedmont of the Taihang Mountains. The purpose of this study is to estimate the groundwater renewal rate in an unconfined aquifer in the Shijiazhuang area based on tritium content and to discuss the changes of renewal rate along the flow path further. The results suggested that the mean annual renewal rates decrease with the depth of water table and the distance from the Hutuo River increasing. The mean annual renewal rates range from 5% a-1 to 33% a-1 of the aquifer volume in the upper part of alluvial fan and decrease to 3%—12% a-1 down- gradient to Shijiazhuang city. In the water depression area of Shijiazhuang, the mean annual renewal rates are 1% a-1 to 5% a-1 of the aquifer volume. If the median value is adopted as the representative of overall renewal rate of the area, the estimated recharge rate is about 242mm/a.关键词：Groundwater recharge;Radionuclides;Tritium;Renewal rate;North China Plain
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发布时间：2021-03-12 - 摘要：The basic principles and some kinds of voltaic effect type radioisotope batteries are reviewed. This paper is focused on the micro-batteries based on radio-voltaic effect, which are widely used in micro-electromechanical sys- tems (MEMs) and cardiac pacemakers. The prospects of such radio-voltaic isotope batteries are also reported.关键词：Decay energy;Radioisotope battery;Volta effect
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发布时间：2021-03-12 - 摘要：The Tcm labeled zoledronate (99Tcm-ZL) was prepared by the reduction of Na99TcmO4 with SnCl2 2H2O. 99 ˙ The effect of the amounts of SnCl2 2H2O and ZL, and pH value on the labeling yield and radiochemical purity of ˙ 99Tcm-ZL were investigated. When the amounts of SnCl2 2H2O and ZL were more than 40 μg and 2mg, respectively, ˙ the pH value was between 3 and 9, and the labeling reaction continued for 8min at room temperature, both labeling yield and radiochemical purity of Tcm-ZL were over 90%. The biodistribution in mice and bone scan in rabbit of 99 99Tcm-ZL were also studied. The results show that at 30min after injection of Tcm-ZL, the uptake in bone was up to 99 13.45%ID/g, bone-to-muscle and bone-to-blood uptake ratios were 28.01 and 16.96, respectively. The clear bone-imaging was obtained at 75min after injection of Tcm-ZL. So Tcm-ZL was a potential bone-imaging agent. 99 99
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发布时间：2021-03-12 - 摘要：To investigate the effect of low dose irradiation on gene transfer efficiency and the effect of adenovi- ral-mediated exogenous P53 overexpression on radiosensitivity of radioresistant human melanoma cell line A375 with wild type p53, control vector, a replication deficient recombinant adenoviral vector containing a CMV promoter and green fluorescent protein (AdCMV-GFP), was used to transfect the A375 cells preirradiated with or without 1 Gy X-ray radiation. The transduction efficiency of GFP gene was determined with fluorescence microscope directly. A375 cells radiated by 1 Gy X-ray were transfected with a replication deficient recombinant adenoviral vector carry- ing human wild p53 (AdCMV-P53), and mRAN level was detected by RT-PCR. The cell cycle delay and the expres- sion of exogenous P53 were detected using flow cytometry (FCM) at different time after transfection. The radiosen- sivity of A375 cells after p53 transduction was assayed by clonoy formation. We found that 1Gy exposure increased the gene transfer efficiency of A375 cells. The expression of exogenous P53 was found to be 60% to 80% of trans- fected cells during the first three days after transduction and then declined continuously down to the control level on the day 10. The G1 cell cycle arrest was also observed after p53 gene transfer. A375 cells that were transfected with p53 showed higher sensitivity to X-ray –induced cell killing than those cells that either were transfected with the viral vector carrying a green fluorescent protein gene or were not transfected at all. Low dose ionizing radiation can im- prove gene transfer efficiency of A375 cells mediated by adenovirus vector. Althrough the overexpresion of exoge- nous P53 may not inhibit cell growth and induce apoptosis of melanoma cell line A375 in vitro, it made the tumor cells much sensitive to death by irradiation. The data suggested that p53 gene might be a potential gene for melanoma therapy and provide the experimental evidences to clinically using the combination of radiation with gene therapy on melanoma. Namely, there may be a reduction of side effects resulting from high dose radiation on radioresistant tu- mors or rAd-P53 administration alone in clinical applications.关键词：p53 gene;Adenovirus vector;Irradiation;Gene therapy;Melanoma
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发布时间：2021-03-12 - 摘要：Three amino acids residues of Arg-Gly-Asp (RGD) are often the primary site of recognition by integrins which are responsible for tumor invasion and metastasis. In this research, one peptides containing RGD: HCRGD(D)FC were radiolabeled with 188 Re-tricarbonyl complex. High radiolabeling ratios (>90%) were achieved under the reaction condition of 75℃, 30min. The radiolabeled peptide got high stability in PBS at room temperature for 4 hours. The hemolysis of red blood cells was not observed during incubation at 37℃ for 3 hours. Biodistribution studies were performed in normal male mice and S180-bearing mice, respectively. The radioactivities were rapidly eliminated by the hepatobiliary and urinary systems. Tumor/Muscle ratios were 4.4075±0.1139, 5.1510±0.5375, 4.4727±0.4895 and 4.8788±3.16 at 1h, 4h, 24h and 48h after injection. The results showed that 188Re-tricarbonyl peptide containing RGD was a potential agent for tumor treatment.关键词：188Re-tricarbonyl complex;RGD-containing peptides;Biodistribution
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发布时间：2021-03-12 - 摘要：This is a review of methods and techniques of precise time interval measurement for particle physics ex- periments. The primary functions of precise time interval measurement in particle physics experiments and the re- quirements of electronics for precise time interval measurement are described. The essential electronic methods used for precise time measurement are discussed, with an emphasis on classification and various techniques of the time in- terpolation.关键词：Time interval measurement;Time-digital conversion;Time interpolation
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发布时间：2021-03-12 - 摘要：This paper introduces the principle and design of a new integration cell for a long pulse integrator with ul- tra-low drift. Based on principles of zero compensation and chopper, the integration cell was designed and developed, and it will be used to constitute an integrator, to complete integration of a long duration of pulse up to one thousand second on the super-conducting tokama facility. Compared with the traditional analog integrator, this integration cell has ultra-low drift with a typical absolute drift value of 16.7mV, when the time constant is 9.78ms. Secondly, its nonlinear error caused by the capacity leakage was also well diminished.关键词：Integration cell;Ultra-low drift;Zero compensation
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发布时间：2021-03-12 - 摘要：The paper introduces a high-powered embedded module 386SX CPU and the system structure of a portable alpha surface contamination meter based on it, and illustrates in detail the design idea and implementation technology of hardware and software. Through a comparative experiment with a standard source of 239Pu, the detection efficiency and other main characteristics were obtained. The instrument is easy to manipulate, can provide accurate measuring results and therefore meet the needs of most consumers.关键词：Embedded module;α-ray;Au-Si surface barrier detector;Surface contamination meter;Detection efficiency
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发布时间：2021-03-12 - 摘要：A new method was developed to measure the neutron albedo by the Monte Carlo code and the activation method. The total neutron fluence at various places on the capture apparatus’ surface was measured by the activation method, and the fluence ratios of incident to reflected neutrons at these places were calculated by MCNP. The meas- urement results were modified by the calculation and an important parameter “neutron albedo” upon the capture ap- paratus was obtained. This parameter would provide a reference for the parameter’s measurement and practical appli- cation of thermal neutron radiography in the pulsed reactors.关键词：Neutron capture apparatus;Albedo;Monte Carlo method;Activation method
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发布时间：2021-03-12 - 摘要：Using Cs2CO3, BaCO3, Al2O3 and TiO2 as raw materials, the single phase solid solution of hollandite cou- taining solid-dissolved cesium is synthesized by high temperature solid phase reaction. The volatilization of cesium at high temperature, the synthesis temperature, the phase structure, etc. are studied through thermogravimetry-differential thermal analysis, X-ray diffraction analysis, wave dispersion spectrum and so on. We have solved many key techno- logic problems such as the formula design of single phase solid solution of hollandite containing solid-dissolved ce- sium and the best synthesis temperature.关键词：Hollandite;Solid solution;Cesium
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发布时间：2021-03-12
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