Studying a kind of portable ultra-bright microfocus x-ray source

This paper studies the properties of a kind of portable ultra-bright microfocus x-ray source with the Monte-Carlo method in detail. The new x-ray source consists of an electron-emission system, an electrostatic focusing system and a metal target. A crystal Lanthanum Hexaboride cathode, a Wehnelt grid and an extracted electrode compose the triode electrode electron-gun system. Two equal radius cylinder electrodes form the focusing system. The key factors determining the focus properties of the electron beam such as the ratio Dw/H, grid bias Vg, and the properties of the extracted electrode arc numerically studied. The calculated results reveal that when Dw/H, Vg, the length of the extracted electrode, and the distance between the grid and the extracted electrode equals 5, q）.6 kV, 10 mm, and 8 mm respectively, the electron beam focal spot can be concentrated down to 9 μm in radius and a reasonable focal length about 72.5 mm can be achieved, at the same time, the cathode emission currents can be as high as 30 mA.

Multiple-stacked Hybrid Plays of lacustrine source rock intervals：Case studies from lacustrine basins in China

Hydrocarbon-producing lacustrine basins are widely developed in the world, and China has a large number of lacustrine basins that have developed since the early Permian. The organic-rich shale-dominated heterogeneous source rock intervals in Chinese lacustrine basins generally contain frequent thin interbeds of stratigraphically associated sandstone, siltstone, marl, dolomite, and limestone. The concept of ‘‘Hybrid Plays＇ ＇ as put forth in this article recognizes this pattern of alternating organicrich shale and organic-lean interbeds and existence of mixed unconventional and conventional plays. Hybrid Plays in lacustrine source rock intervals present a unique closed petroleum system hosting continuous hydrocarbons.The interbedded organic-lean siliciclastic and/or carbonateplays are efficiently charged with hydrocarbons via short migration pathways from the adjacent organic-rich shale that is often also a self-sourced play. We assert ‘‘Hybrid Plays＇ ＇ provide the most realistic exploration model for targeting multiple-stacked and genetically related very tight shale, tight and conventional plays together in the entire source rock interval rather than individual plays only. The Hybrid Play model has been proven and works for a wide variety of lacustrine rift, sag and foreland basins in China.

Negative Corona Discharge Ion Source Under Ambient Conditions with Mini Line-cylinder Electrodes

A novel ambient negative corona discharge ion source with mini line-cylinder electrodes is designed. The diameters of inner and outer electrode are 0.16 and 4 mm respectively. With a special assembly method, a perfect coaxiality of the two electrodes is obtained. An injection system utilizing a temperature control technique, achieves a constant and stable concentration of the sample, which is critical to the experiment. The formulas of the corona onset voltage of line-cylinder electrodes are also introduced. The experiment results show that negative substances such as formic acid and acetic acid can be ionized under ambient conditions. When combined with micro electrical mechanical system fabricationprocess, the volume of the ion source can be reduced dramatically, but there is an undesirable surface discharge. To solve the surface discharge problem, an improved structure was designed and tested. The simplicity of the interface of the ion source makes it suitable for mass spectrometer, micro mass spectrometer, ion mobility spectrometer, and high-field asymmetric waveform ion mobility spectrometer applications.

Numerical study on wave loads and motions of two ships advancing in waves by using three-dimensional translating-pulsating source

A frequency domain analysis method based on the three-dimensional translating-pulsating （3DTP） source Green function is developed to investigate wave loads and free motions of two ships advancing on parallel course in waves. Two experiments are carried out respectively to mea- sure the wave loads and the free motions for a pair of side-by- side arranged ship models advancing with an identical speed in head regular waves. For comparison, each model is also tested alone. Predictions obtained by the present solution are found in favorable agreement with the model tests and are more accurate than the traditional method based on the three dimensional pulsating （3DP） source Green function. Numer- ical resonances and peak shift can be found in the 3DP pre- dictions, which result from the wave energy trapped in the gap between two ships and the extremely inhomogeneous wave load distribution on each hull. However, they can be eliminated by 3DTP, in which the speed affects the free sur- face and most of the wave energy can be escaped from the gap. Both the experiment and the present prediction show that hydrodynamic interaction effects on wave loads and free motions are significant. The present solver may serve as a validated tool to predict wave loads and motions of two ves- sels under replenishment at sea, and may help to evaluate the hydrodynamic interaction effects on the ships safety in replenishment operation.

Study on Ecological Compensation Policy among the Micro Subjects on Water Energy Resources Development

The subjects of ecological compensation involve the nation, society, development enterprises of wa-ter-energy resources, as well as the location of resource itself. This paper systematically studies on how to make “water energy sources market compensation policy”, “the economic compensation policy for relevant interest subjects” and “the ecological compensation policy of basin ecological water.” So, it is necessary to exert the complementary function between market compensation and government compensation by the means of economic compensation and to establish the ecological compensation policy of basin ecological water, which is beneficial to coordinating the stakeholders’ interests of cross-region or inter-basin. And it is important and significant to establish constantly perfected ecological compensation policy among the micro subjects on water energy resources development, so as to coordinate interest relationships among various subjects and finally reach the aim of sustainable use of water energy resources and environmental protection as possible.

Cross-Correlation Detection of Point Sources in the WMAP First Year Data

We apply a Cross-Correlation （CC） method developed previously for detecting gamma-ray point sources to the WMAP first year data by using the Point-Spread Function of WMAP and obtain a full sky CC coefficient map. We find that the CC method is a powerful tool to examine the WMAP foreground residuals which can be further cleaned accord- ingly. Evident foreground signals are found in the WMAP foreground cleaned maps and the Tegmark cleaned map. In this process 101 point sources are detected, and 26 of them are new sources additional to the originally listed WMAP 208 sources. We estimate the flux of these new sources and verify them by another method. As a result, a revised mask file based on the WMAP first year data is produced by including these new sources.

An Air-Breathing Micro Direct Methanol Fuel Cell with 3D KOH-Etched Cathode Structure

A micro direct methanol fuel cell （μDMFC） using MEMS technology is reported. The prototype features a unique 3D air-breathing cathode structure fabricated using KOH etching and double-side lithography. The optimization of the MEMS fabrication process is analyzed. The experimental results show the prototype generates a maximum power density of 2.52mW/cm^2 at room temperature. This performance is better than the published resuits of other silicon-based passive μDMFCs. Moreover,it is comparable with that of our previous active μDMFCs which require an external pump, certificating the feasibility of this new configuration.

5-羟色胺转运蛋白显像剂^(11)C-DASB的自动化合成及Micro PET/CT显像

目的:自动化合成5-羟色胺转运蛋白显像剂11 C-DASB并进行大鼠Micro PET/CT显像;方法:通过改变甲基化试剂、溶解前体溶剂及反应条件,得到优化的标记条件作为碳-11多功能合成模块的输入参数,进行自动化合成11 C-DASB,大鼠静脉注射11 C-DASB 45 min后进行显像;结果:采用11 C-CH3-Triflate作为甲基化试剂,通入新配制的含1mg去甲基DASB前体的500μL DMSO溶液内,80℃下加热2min,标准率为63.7%,大鼠显像表明,11 C-DASB特异性的浓聚于SERT富集区域;结论:经优化,11 C-DASB自动化合成可得到较高产率,大鼠显像表明,其特异性浓聚于SERT富集区域,有望作为5-羟色胺转运蛋白显像剂。

^(18)F-氟赤硝基咪唑micro PET/CT评价裸鼠乳腺癌早期放疗疗效实验研究

目的探讨^(18)F-氟赤硝基咪唑micro PET/CT评价裸鼠MDA-MB231乳腺癌早期放疗疗效的价值。方法建立16只裸鼠MDA-MB231乳腺癌模型,将其按照随机对照原则分为两组:对照组(A组)、放疗组(B组),每组8只。每组裸鼠行micro PET/CT显像,测定每只裸鼠肿瘤SUVmax值。完成显像后,常规HE染色观察每组肿瘤组织形态学特征,免疫组化方法测定每组肿瘤细胞乏氧诱导因子-1α(HIF-1α)的表达情况。结果放疗前,对照组与放疗组SUVmax值差异无统计学意义(t=0. 375,P> 0. 05)。放疗组放疗后48 h裸鼠肿瘤组织SUVmax值较放疗前(t=9. 958,P <0. 05)、放疗后24 h(t=16. 506,P <0. 05)明显降低,差异有统计学意义(F=58. 860,P <0. 05)。放疗后24 h SUVmax值也低于放疗前24 h(t=5. 405,P <0. 05),差异有统计学意义。HE染色结果显示放疗组肿瘤细胞坏死较对照组更加明显。免疫组化结果显示放疗组放疗后HIF-1α表达阳性率明显低于放疗前(t=14. 802,P <0. 05),差异具有统计学意义。相关性分析结果显示肿瘤SUVmax与HIF-1α的表达呈明显正相关性(r=0. 865,P <0. 05)。结论^(18)F-氟赤硝基咪唑micro PET/CT可以监测肿瘤内部的乏氧状态,并且可以评价裸鼠MDA-MB231乳腺癌的早期放疗疗效。

基于遗传-模式搜索算法的微尺度管控区域大气污染物PM2.5溯源

针对微尺度管控区域可能发生的大气污染提出有效的靶向诊断方法-结合高斯烟羽模型和遗传-模式搜索算法的大气污染物分布式溯源方法.将污染源反算模型得到的污染物理论质量浓度与传感器网络观测值的数据对应关系作为目标函数,使用模式搜索算法嵌入遗传算法加快反算模型的搜索过程,反算得到污染源强度和位置.依托杭州市亚运板球场馆大气感知器网络进行实验验证,监测2021年10月PM2.5质量浓度、气象数据,对所提出的混合式大气污染溯源方法进行实验验证.实验结果表明:改进遗传-模式搜索算法对于多维变量的搜索效果较好,能快速精准地反算污染源的位置和强度,可以为微尺度管控区域突发性气体污染防治提供应急决策参考.

基于电子束扫描阵列微焦点射线源的倒置结构Micro-CT成像研究

倒置几何结构CT成像系统理论上具有扫描视场大、图像信噪比好、锥束伪影小等优点,但其多焦点、稀疏角的扫描模式亦会带来投影数据截断、稀疏和局部数据冗余等问题。本文利用电子束扫描阵列微焦点射线源和高分辨率小面积探测器等构建了一种新型高分辨率、大视场的倒置几何结构Micro-CT实验系统(IG-Micro-CT)。针对该系统多焦点、稀疏角扫描模式下的投影数据截断和稀疏等特点,提出一种图像先验约束的全变分正则化SART迭代CT图像重建算法。首先通过仿真实验对图像重建算法进行了验证,并对阵列微焦点数量、旋转扫描分度数量等扫描参数进行优化,最后在IG-Micro-CT实验系统上获得了高分辨的Micro-CT测试图像。实验结果表明,本文提出的算法适用于IG-Micro-CT系统,解决了投影数据截断、稀疏采样和局部数据冗余带来的条状等伪影问题,并验证了IG-Micro-CT这种新型成像方式的可行性。

A new approach to numerical simulation of source development of earthquake

By considering the heterogeneity of geomechanical materials, the source development of earthquake under compression boundary conditions is studied with a newly developed numerical method, Rock Failure Process Analysis code (RFPA2D). The process of fault forming and associated micro seismicities in a rectangle area with a inclusion but without any clear structural features of original fault is modeled. The modeling demonstrates the whole process of source development of earthquake from deformation, micro failure to collapse and the behavior of temporal spatial distribution of micro seismicities. The stress, strain and the temporal spatial distribution of micro seismicities vividly depict the phenomena of localization, temporal transitions, dilatation or rise, elastic rebound and conjugate (X type) deformation zone.

Design and Testing of Three Earthing Systems for Micro-Grid Protection during the Islanding Mode

This paper presents and tests three earthing systems (TT, TN and IT) for Micro-Grid (MG) protection against various fault types when the MG transferred to the islanding mode. The main contribution of this work is including the models of all micro sources which interfaced to the MG by power electronic inverters. Inverters in turns are provided with current limiters and this also included with the inverter models to exactly simulate the real situation in the MG during fault times. Results proved that the most suitable earthing system for MG protection during the islanding mode is the TN earthing system. That system leads to a suitable amount of fault current sufficient to activate over current pro-tection relays. With using TN earthing system, touch voltages at the faulted bus and all other consumer’s buses are less than the safety limited values during islanding mode. For the two others earthing systems (TT and IT), fault currents are small and nearly equal to the over load currents which make over current protection relay can not differentiate between fault currents and overload currents. All models of micro sources, earthing systems, inverters and control schemes are built using Matlab?/Simulink? environment.

Comparison the Performances of Three Earthing Systems for Micro-Grid Protection during the Grid Connected Mode

This paper presents, tests and compares three earthing systems (TT, TN and IT) for Micro-Grid (MG) protection against various fault types during the connected mode. The main contribution of this work is including the models of all the micro sources which interfaced to the MG by power electronic inverters. Inverters in turns are provided with current limiters and this also included in the inverter models to exactly simulate the real situation in the MG during fault times. Results proved that the most suitable earthing system for MG protection during the connecting mode is the TN earthing system. That system leads to a suitable amount of fault current sufficient to activate over current protection relays. With using TN system, Touch voltages at the faulted bus and all other consumer’s buses are less than the safety limited value if current limiter is included with the transformer of the main grid which connects MG. For the two others earthing systems (TT and IT), fault current is small and nearly equal to the over load current which make over current protection relay can not differentiate between fault current and overload current. All models of micro sources, earthing systems, inverters, main grid and control schemes are built using Matlab?/Simulink? environment.

Semiannual velocity variations around the 2008 M_w 7.9 Wenchuan Earthquake fault zone revealed by ambient noise and ACROSS active source data

We continuously monitor the long-term seismic velocity variation of one of the major ruptured faults of the devastating 2008 Mw7.9 Wenchuan earthquake in China from July 2009 to January 2012,jointly using accurately controlled routinely operated signal system active source and seismic noise-based monitoring technique.Our measurements show that the temporal velocity change is not homogeneous and highly localized in the damaged fault zone and the adjacent areas.Velocity variations from the active and passive methods are quite consistent,which both are characterized by ±0.2 % seasonal variation,with peak and trough at winter and summer,respectively.The periodic velocity variation within fault zone exhibits remarkably positive correlation with barometric pressure with stress sensitivity in the order of 10-6Pa-1,suggesting that the plausible mechanism might be the crack density variation of the shallow subsurface medium of the damaged fault zone in response to the cyclic barometric pressure loading.

Characteristics and distributions of atmospheric mercury emitted from anthropogenic sources in Guiyang, southwestern Chin

Continuous measurements of speciated atmo- spheric mercury （Hg）, including gaseous elemental mer- cury （GEM）, particulate mercury （PHg）, and reactive gaseous mercury （RGM） were conducted in Guizhou Pro- vince, southwestern China. Guiyang Power Plant （GPP）, Guiyang Wujiang Cement Plant, Guizhou Aluminum Plant （GAP）, and Guiyang Forest Park （GFP） in Guiyang were selected as study sites. Automatic Atmospheric Mercury Speciation Analyzers （Tekran 2537A） were used for GEM analysis. PHg and RGM were simultaneously collected by a manual sampling system, including elutriator, coupler/ impactor, KCl-coated annular denuder, and a filter holder. Results show that different emission sources dominate different species of Hg. The highest average GEM value was 22.2 ±28.3 ng·m-3 and the lowest 6.1 ± 3.9 ng·m-3, from samples collected at GPP and GAP, respectively. The maximum average PHg was 1984.9 pg·m-3 and the mini- mum average 55.9 pg·m-3, also from GPP and GAP, respectively. Similarly, the highest average RGM of 68.8 pg·m-3 was measured at GPP, and the lowest level of 20.5 pg·m-3 was found at GAP. We conclude that coal combustion sources are still playing a key role in GEM; traffic contributes significantly to PHg; and domestic pol- lution dominates RGM.

RELATIONSHIP BETWEEN THE 30 TO 60 DAY OSCILLATION OF ATMOSPHERIC HEAT SOURCE AND THE DROUGHT AND FLOOD EVENTS IN JUNE IN THE SOUTH OF CHINA

Based on the NCEP/NCAR reanalysis data and the observed precipitation data in the south of China from 1958 to 2000,the impact of 30 to 60 day oscillation of atmospheric heat sources on the drought and flood events in June in the south of China is discussed.During the flood(drought) events,there exists an anomalous low-frequency anticyclone(cyclone) at the low level of the troposphere over the South China Sea and the northwestern Pacific,accompanied with anomalous low-frequency heat sinks(heat sources),while there exists an anomalous low-frequency cyclone(anticyclone) with anomalous heat sources(sinks) over the area from the south of China to the south of Japan.On average,the phase evolution of the low-frequency in drought events is 7 to 11 days ahead of that in flood events in May to June in the south of China.In flood events,low-frequency heat sources and cyclones are propagated northward from the southern South China Sea,northwestward from the warm pool of the western Pacific and westward from the northwestern Pacific around 140°E,which have very important impact on the abundant rainfall in June in the south of China.However,in drought events,the northward propagations of the low-frequency heat sources and cyclones from the South China Sea and its vicinity are rather late compared with those in flood events,and there is no obvious westward propagation of the heat sources from the northwestern Pacific.The timing of the low-frequency heat source propagation has remarkable impact on the June rainfall in the south of China.

Silicon Isotope Geochemistry of Micro-Fine Disseminated Gold Deposits in SW Guizhou and NW Guangxi,China

Quartz was studied with respect to its silicon isotopic composition and cathodoluminescence in micro-fine disseminated gold deposits in SW Guizhou and NW Guangxi. The resultsshowed that quartz in wall rocks, ores and that in association with hydrothermal silicificationare distinctive in silicon isotopes and cathodoluminescence characters. Quartz in association withprimary silicification is non-luminescent while that in wall rocks and associated with secondarysilicification exhibits striking luminescence. Based on the dynamic fractionation of silicon isotopes, it is suggested that the mineralization was accompanied by rapid transport of a primarysiliceous fluid along the major deep fault system into subordinate faults before ore componentsdeposited in favorable strata via penetration and metasomatism. Therefore, a deep origin is implicit for gold deposits of this type.

Source and yearly distribution of PAHs in the snow from the Hailuogou glacier of Mountain Gongga, China

Snow samples were collected over a 3-year period from 2012 to 2014 at the Hailuogou glacier of Mountain Gongga(Mt. Gongga) and analyzed for 16 priority polycyclic aromatic hydrocarbons(PAHs) using Gas Chromatography–Mass Spectrometry(GC–MS). The results show that total average levels of the 16 PAHs ranged from 452 to 290 ng·L^(-1) with a possible declining trend from 2012 to 2014. Distances between the sampling sites and the emission sources were estimated at typically less than 500 km. The results suggest that the major source of PAHs was from coal combustion, while contributions from automobile exhaust played an important role in more recent years. This finding was in agreement with the characteristics of presence of local industry, residence, and recent development of tourism of the surrounding areas.

Control System Development and Test for the Operation of a Micro-Grid System—PART I

This paper presents design, analysis and simulation performance of an active power controller for stable and reliable operation of a micro-grid system. Power balance between generation and consumer is a critical issue for stable and reliable operation of the micro-grid systems. This issue becomes more critical when a micro-grid system contains stochastic nature distributed generations such as wind and solar because their output power changes non-uniformly. In order to achieve accurate and fast power balance in such a micro-grid system, power in the system has to be regulated continuously. Such an objective can be achieved using droop based alternating current control technique. Because the droop characteristic employed into the developed controller initiates determining the power deviation in the system which is continuously regulated by controlling the current flow into dump power resistors. The designed controller is simulated for the operation of a micro-grid system in stand-alone mode under various operating conditions. The simulated results show the ability of the developed controller for stable and reliable operation of the micro-grid that contains renewable sources. The experimental development of the micro-grid system and the testing of the developed active power controller are presented in PART II of this paper.