First description of Blastocystis sp. and Entamoeba sp. infecting zoo animals in the Qinghai-Tibetan plateau area, China

Protozoan parasites are a well-known threat to human health, particularly for people working at or visiting zoos, and potentially cause zoonotic diseases in humans. Captive wildlife may be potential reservoirs for human infection with protozoan parasites. Therefore, focusing on zoonotic protozoan infections in zoo animals is critical. However, there is no report on this topic in the Qinghai-Tibetan Plateau region. In this study, a total of 167 and 103 fecal samples were collected from 12 animal species from Qinghai-Tibet Plateau Wildlife Park in winter and summer, respectively, to detection the prevalence of infections and subtype distribution with Entamoeba sp., Cryptosporidium sp., Giardia duodenalis, Enteromicrosporidia bieneusi sp., Blastocystis sp. by PCR assay. The results showed that a total of 21 fecal samples collected in winter, including from 2 white-lipped deer, 8 Sika deer, 6 blue sheep, 2 wolves and 3 bears, were positive for Entamoeba, with a 12.6% (21/167) positive rate. However, 4.9% (5/103) of animals in summer were positive for Entamoeba, including 1 snow leopard, 1 tiger, 1 Tibetan argali and 2 mouflon. Moreover, 1 white-lipped deer and 1 bear were found to be positive for Blastocystis sp., one zoonotic STs (ST10) was identified and found in white-lipped deer. We found no effect on season on Blastocystis sp. and Entamoeba sp. colonization. To the best of our knowledge, this study is the first description of Blastocystis sp. and Entamoeba sp. infecting zoo animals in the plateau area. The findings provide the latest data on Entamoeba sp. and Blastocystis sp. in zoo animals in China

Design of a high current ion source for an electromagnetic isotope separator

BackgroundStable isotopes play a crucial role in a variety of fields such as energy, military, semiconductor, agriculture, medicine, pharmacology, biology, food industry, and chemistry. With the rapid growth of nuclear science and technology applications in China, there has been an increasing demand for isotopes that cannot be met by current production capacities. Thus, the development of electromagnetic isotope separators capable of producing high yields and high isotopic purity has become necessary.PurposeThis study aims to develop an electromagnetic isotope separator based on a 2.45 GHz microwave ion source and isotopic magnet for studying a number of important heavy isotopes, such as xenon and molybdenum isotopes.MethodsFirstly, adjustable axial magnetic field in the source was designed by a double-solenoids to obtain high density plasma, and a high coupling efficiency matching waveguide was optimized by CST microwave computing module. Then. a crucible built in the discharge chamber was used to melt metal oxide for generating heavy metal ion beams. Finally, the discharge chamber, microwave coupling waveguides and heating oven of the ion source were simulated and designed for the generation of heavy ions.ResultsSimulation result shows that the temperature around the crucible is 917 ℃ when the current of heating wire is set to 70 A, and 100 mA hydrogen beam is generated during commissioning. The designed crucible in the discharge chamber can generate metal vapor efficiently for ionization, and achieve producing 20 emA Xe+ and 5 emA Mo+ respectively at the energy of 40 keV.ConclusionsThe feasible scheme of the magnetic field and microwave coupling design of this study are verified. The design of the 2.45 GHz electron cyclotron resonance (ECR) ion source provides a feasible and effective solution for the high yields isotope ions

耦合带状线定向耦合器大功率合成器的设计

<span style="color: rgb(51, 51, 51); font-family: arial, helvetica, sans-serif; font-size: 13px; line-height: 22px; background-color: rgb(248, 248, 248);">介绍了直线加速器高频全固态功率源中大功率合成器件-3 dB定向耦合器的理论计算和工程设计过程,该合成器工作频率80.5 MHz,输出连续波功率大于20 kW。分析了合成器的功率容量,并对相应的理论计算结果、CST(Computer Simulation Technology)软件模拟计算结果和实际功率合成器件测量结果进行了比较。通过比较得出,CST仿真结果与测试结果基本一致,隔离度和电压驻波比等实测指标优于设计指标,只有耦合度与设计指标有些偏差,总体上达到了预期的设计要求。在输出功率20 kW时,取样波形无失真,合成器无明显温升,满足固态功率源大功率稳定运行的要求。</span><span style="color: rgb(51, 51, 51); font-family: arial, helvetica, sans-serif; font-size: 13px; line-height: 22px; background-color: rgb(248, 248, 248);">The principle of design and calculation of the power synthesis in the solid-state amplifier are described in this paper.The working frequency of the synthesizer is 80.5 MHz.The output continuous wave power is more than 20 kW;The synthesizer power capacity is analyzed.The theoretical calculation results,Computer Simulation Technology(CST) simulated results are compared with the measured results of the actual 3 dB couplers.The analysis of the measured results and CST calculated results shows that the simulation is in agreement with the measurement results which meet the design requirements of the solid-state amplifier.Except the coupling coefficient,the isolation,the VSWR and other parameters are better than the design target.When the output power is 20 kW,the sampling waveform has no deform and the temperature of the synthesizer is stable.</span

螺线管透镜像差导致的束流发射度增长研究

<span style="color: rgb(51, 51, 51); font-family: arial, helvetica, sans-serif; font-size: 13px; line-height: 22px; background-color: rgb(248, 248, 248);">螺线管透镜常作为低能束流的聚焦元件,不可避免地具有像差,导致束流发射度增长,降低束流传输效率。本文通过理论推导和计算机模拟,给出了不同束流包络、不同磁感应强度和不同磁场形状的情况下束流经过实际透镜后的发射度增长。结果表明,发射度增长主要与束流包络和磁感应强度有关。但在一定范围内,优化磁场形状也能起到控制发射度增长的作用。</span><span style="color: rgb(51, 51, 51); font-family: arial, helvetica, sans-serif; font-size: 13px; line-height: 22px; background-color: rgb(248, 248, 248);">T he solenoid lens are effective for focusing the low energy beam, but the beam efficiency decreases with the beam emittance growth,which increases with the spherical aberration of solenoid lens.Emittance grow th due to spherical aberration of solenoid lens was studied in both theory and simulation in this paper.The results show that emittance grow th is mainly dominated by the beam envelope in lens and magnetic strength of lens. Optimizing the magnetic field uniformity of solenoid lens, which decides the aberration coefficient,can reduce the spherical aberration and enhance the quality of beam to an ex tent.</span

Development of higher power density evaporative cooling magnet coils in ECR ion source

<span style="color: rgb(51, 51, 51); font-family: arial, helvetica, sans-serif; font-size: 13px; line-height: 22px; background-color: rgb(248, 248, 248);">Traditional electron cyclotron resonance ( ECR) ion source coil with higher power density have some disadvantages, such as high pressure in the water-cooling system, restricted cooling ability, complex maintenance and operation system. A new ECR ion source coil was designed by using self-circulation evaporative cooling technology. The new design is based on the principle of self-circulation evaporative cooling, besides, the layout structure of ECR ion source coil and high operation reliability are both considered. The coil is composed by disk coil arrays. Vertical cooling channels are set among unit coils, where evaporative cooling coolant flows automatically driven by the heat of coils. According to the parameter index of LECR - DRAGON ion source magnet coil, the test model of evaporative cooling magnet coil was built. The experimental results show that the window current density of the new designed coil can be 12A/mm</span><sup style="margin: 0px; list-style: none; padding: 0px; color: rgb(51, 51, 51); font-family: arial, helvetica, sans-serif; line-height: 22px; background-color: rgb(248, 248, 248);">2</sup><span style="color: rgb(51, 51, 51); font-family: arial, helvetica, sans-serif; font-size: 13px; line-height: 22px; background-color: rgb(248, 248, 248);">&nbsp;, which can maintain a long-term stable and reliable running. The evaporative cooling magnet coil can meet the requirements of practical engineering.</span