Study of the aberrations of the IMP heavy ion microbeam irradiation system

A high energy heavy ion microbeam irradiation system is constructed at the Institute of Modern Physics (IMP) of the Chinese Academy of Sciences (CAS). A quadrupole focusing system, in combination with a series of slits, has been designed here. The IMP microbeam system is described in detail. The intrinsic and parasitic aberrations associated with the magnets are simulated. The ion beam optics of this microbeam system is investigated systematically. Then the optimized initial beam parameters are given for high spatial resolution and high hitting rates.

Design of the IMP microbeam irradiation system for 100 MeV/u heavy ions

Abstract A state-of-the-art high energy heavy ion microbeam irradiation system is constructed at the Institute of Modern Physics of the Chinese Academy of Sciences. This microbeam system operates in both full current intensity mode and single ion mode. It delivers a predefined number of ions to preselected targets for research in biology and material science. The characteristic of this microbeam system is high energy and vertical irradiation. A quadrupole focusing system, in combination with a series of slits, has been designed to optimize the spatial resolution. A symmetrically achromatic system leads the beam downwards and serves simultaneously as an energy analyzer. A high gradient quadrupole triplet finally focuses a C6+ ion beam to 1 µm in the vacuum chamber within the energy range from 10 MeV/u to 100 MeV/u. In this paper, the IMP microbeam system is described in detail. A systematic investigation of the ion beam optics of this microbeam system is presented together with the associated aberrations. Comparison is made between the IMP microbeam system and the other existing systems to further discuss the performance of this microbeam. Then the optimized initial beam parameters are given for high resolution and high hitting efficiency. At last, the experiment platform is briefly introduced.

Monte Carlo studies of micromegas as a neutron detector and its track reconstruction

In this paper a two dimensional readout micromegas detector with a polyethylene foil as converter was simulated on GEANT4 toolkit and GARFIELD for fast neutron detection. A new track reconstruction method based on time coincidence technology was developed in the simulation to obtain the incident neutron position. The results showed that with this reconstruction method higher spatial resolution was achieved.

Simulation of micromegas detector by garfield program

In this paper, a batch file which describes the detailed structure and the corresponding physical process of Micro-Mesh Gaseous Structure (Micromegas) detector, the macro commands and the control structures based on the Garfield program has been developed. And using the Garfield program controlled by this batch file, the detector's gain and spatial resolution have been investigated under different conditions. These results obtained by the simulation program not only exhibit the influences of the mesh and drift voltage, the mixture gas proportion, the distance between the mesh cathode and the printed circuit board readout anode, and the Lines Per Inch of the mesh cathode on the gain and spatial resolution of the detector, but also are very important to optimize the design, shorten the experimental period, and save cost during the detector development. Additionally, they also indicate that the Garfield program is a powerful tool for the Micromegas detector design and optimization.

A TOF-PET prototype with position sensitive PMT readout

A prototype of time-of-flight positron emission computed tomography (TOF-PET) has been developed for acquiring the coincident detection of 511 keV gamma-rays produced from positron annihilation. It consists of two 80.5 mmx80.5 mm LYSO scintillator arrays (composed of 35 x35 pixel finger crystals) with the position sensitive photomultiplier tubes R2487 as the readout. Each array is composed of 2 mm x2 mm x 15 mm finger crystals and the average pixel pitch is 2.30 mm. The measured results indicate that the TOF information has the potential to significantly enhance the image quality by improving the noise variance in the image reconstruction. The best spatial resolution (FWHM) of the prototype for the pairs of 511 keV gamma-rays is 1.98 mm and 2.16 mm in the x and y directions, respectively, which are smaller than the average pixel pitch of 2.30 mm.

Spatio-temporal changes in annual accumulated temperature in China and the effects on cropping systems, 1980s to 2000

Change in thermal conditions can substantially affect crop growth, cropping systems, agricultural production and land use. In the present study, we used annual accumulated temperatures > 10 degrees C (AAT10) as an indicator to investigate the spatio-temporal changes in thermal conditions across China from the late 1980s to 2000, with a spatial resolution of 1 x 1 km. We also investigated the effects of the spatio-temporal changes on cultivated land use and cropping systems. We found that AAT10 has increased on a national scale since the late 1980s, Particularly, 3.16 x 10(5) km(2) of land moved from the spring wheat zone (AAT10: 1600 to 3400 degrees C) to the winter wheat zone (AAT10: 3400 to 4500 degrees C). Changes in thermal conditions had large influences on cultivated land area and cropping systems. The areas of cultivated land have increased in regions with increasing AAT10, and the cropping rotation index has increased since the late 1980s. Single cropping was replaced by 3 crops in 2 years in many regions, and areas of winter wheat cultivation were shifted northward in some areas, such as in the eastern Inner Mongolia Autonomous Region and in western Liaoning and Jilin Provinces.

Uncertainties in estimates of cropland area in China: a comparison between an AVHRR-derived dataset and a Landsat TM-derived dataset

The large uncertainties in estimates of cropland area in China may have significant implications for major cross-cutting themes of global environmental change-food production and trade, water resources, and the carbon and nitrogen cycles. Many earlier studies have indicated significant under-reporting of cropland area in China from official agricultural census statistics datasets. Space-borne remote sensing analyses provide an alternative and independent approach for estimating cropland area in China. In this study, we report estimates of cropland area from the National Land Cover Dataset (NLCD-96) at the 1:100,000 scale, which was generated by a multi-year National Land Cover Project in China through visual interpretation and digitization of Landsat TM images acquired mostly in 1995 and 1996. We compared the NLCD-96 dataset to another land cover dataset at I-km spatial resolution (the IGBP DIScover dataset version 2.0), which was generated from monthly Advanced Very High Resolution Radiometer (AVHRR)-derived Normalized Difference Vegetation Index (NDVI) from April, 1992 to March, 1993. The data comparison highlighted the limitation and uncertainty of cropland area estimates from the DIScover dataset. (C) 2003 Elsevier Science B.V. All rights reserved.

1、吗啡成瘾及吗啡对其他学习记忆的影响 2、老年猕猴初级视觉皮层细胞时间及空间特性的改变

一、 药物滥用是一种慢性、复发性脑疾病。药物滥用将导致药物成瘾（addiction），其主要表现有药物依赖、药物耐受、药物敏感化以及药物停用后的戒断症状（withdraw symptom）。药物成瘾的核心特征是强迫性觅药和用药行为。药物成瘾会导致药物滥用者认知功能的损伤和认知偏差，并会造成滥用者情绪异常。药物成瘾是一个复杂的生物学过程，有着及其复杂的机理。对药物成瘾机制的解释有很多种，主要认为成瘾过程是一种学习记忆过程，学习记忆的机制在药物成瘾过程中起到了非常重要的作用。首先，学习记忆和药物成瘾过程都受到了相似的神经营养因子以及神经递质系统的调控，例如：它们都受cAMP，CREB等调控因子的调控。其次，研究发现与成瘾相关的线索，如用药有关的人物、地点或暗示等，在药物戒断很长时间后都会恢复吸毒者的用药行为。并且，当把与成瘾相关的线索呈现给毒品戒断中的人时，这些人会出现心率、呼吸加快，血压升高等现象，甚至表现出明显的渴求行为。药物对学习记忆的影响是复杂的，虽然重复使用药物会导致药物成瘾，并且这个过程需要学习记忆机制的参与，但同时使用吗啡却会对其他类型的学习记忆（如：恐惧性学习记忆、一次性被动回避学习记忆和水迷宫空间学习记忆）造成破坏。学习前给予吗啡可以剂量及状态依赖地破坏被动回避试验以及空间辨别试验的记忆获取过程。学习过程结束后立即给予吗啡可以破坏一次性被动回避试验、主动回避试验和恐惧条件化试验的记忆巩固过程。测试前给予吗啡可以破坏空间辨别试验的记忆提取过程。本研究的目的在于更进一步地了解使用吗啡导致吗啡成瘾以及使用吗啡导致学习记忆的各个阶段受损的机制。为此我们采用了药理学以及多种行为学的方法，1、用PTZ诱发的癫痫持续状态干扰吗啡成瘾的学习记忆过程，进一步比较了吗啡成瘾的学习记忆与其他学习记忆，例如：空间学习记忆以及食物奖赏学习记忆的机制有何异同；2、研究了β-肾上腺素系统与阿片系统在空间记忆巩固过程中的相互作用；3、我们还研究了NMDA受体的激动剂和拮抗剂在吗啡破坏空间记忆提取过程中的作用。研究结果发现： 1．戊四唑诱发的癫痫持续状态，对吗啡建立的条件化位置偏好没有任何影响，动物仍然对阳性箱（吗啡匹配箱）表现出明显的偏好。但是癫痫持续状态破坏了食物建立的条件化位置偏好，并且还破坏了水迷宫和Y迷宫检测的空间记忆。癫痫持续状态破坏了食物建立的条件化位置偏好，原因不是由于其影响了动物的食欲。此外，癫痫持续状态也没有持续地破坏动物的活动能力，因此，对动物活动量的影响也不是造成其他学习记忆破坏的原因。这些结果说明，吗啡成瘾的学习记忆和普通的学习记忆在机制上可能存在不同之处。为了说明这个问题，我们还需要进行其他更深入的研究。 2、训练后立即单独注射吗啡（0.25和2.5 mg/kg）或心得安（2，10和20 mg/kg）都不会破坏动物Y-迷宫空间记忆的巩固过程，动物仍然能识别新异环境，并在里面停留较长时间。但是，训练后同时注射吗啡和心得安却可以破坏动物空间记忆的巩固过程。并且，较高剂量的吗啡（2.5 mg/kg）加上较高剂量的心得安（10和20 mg/kg）对记忆的破坏更严重，实验组动物在新异环境停留的时间显著低于对照组。这说明阿片系统和去甲肾上腺素系统在破坏记忆巩固的过程中可能有协同作用。 3、记忆提取前30分钟注射吗啡（1和10 mg/kg）可以剂量依赖地破坏Y-迷宫空间记忆的提取。单独注射NMDA受体的激动剂NMDA（1，2和4 mg/kg）对动物的空间记忆提取没有影响，但是，单独注射NMDA受体拮抗剂MK-801（0.05，0.1和0.2 mg/kg）剂量依赖地破坏了空间记忆的提取。同时注射吗啡（10 mg/kg）和NMDA（2 mg/kg）可以阻断吗啡对空间记忆造成的破坏作用。相反，共同注射吗啡（1 mg/kg）和MK-801（0.05 mg/kg）可以加重吗啡对空间记忆造成的破坏作用。这说明谷氨酸系统可以干扰吗啡对记忆提取过程的影响。 二、衰老严重地影响了人们的视觉功能，然而眼睛光学系统的老年性改变并不能完全解释清楚这种视觉功能衰退。一般认为是神经系统的退化导致了这种老年性功能降低。但是，研究显示视网膜（retina）和外膝体（dorsal lateral geniculate nucleus, dLGN）在衰老的过程中神经元的数量和体积以及神经元的功能特性，如对比度敏感性、空间分辨率等，都没有明显的变化，因此，人们推测老化导致的神经系统的变化发生在更高级的视觉皮层。过去几年的研究发现老年动物视觉皮层细胞发生了一系列反应特性的改变，如：老年动物皮层细胞的方向选择性和方位选择性降低以及细胞反应的潜伏期延长。这些细胞水平的变化被认为是老年性视觉功能衰退的神经机制。为了更全面地了解衰老过程对视觉皮层的影响以及细胞反应改变与整体功能降低之间的关系，本研究采用活体动物细胞外单位记录的方法，比较了青年和老年猕猴初级视觉皮层细胞时间反应特性和空间反应特性的差异。研究结果发现：老年动物初级视觉皮层细胞的时间频率和空间频率敏感性明显比年轻动物降低。表现为老年动物初级视觉皮层细胞的最优时间和空间频率、空间分辨率（spatial resolution, SR）和较高时间截至频率（high temporal frequency cut-off, TF50）都显著低于年轻动物初级视觉皮层细胞，同时伴随着这些功能的降低，老年动物初级视觉皮层细胞的自发放增加，对视觉刺激的反应增加，但是信噪比却显著降低。这些结果表明，老年动物初级视觉皮层细胞的功能在老化过程中都普遍降低。这可能是导致老年人视觉功能降低的原因。

COASTAL SEA-LEVEL AND THE LARGE-SCALE CLIMATE STATE - A DOWNSCALING EXERCISE FOR THE JAPANESE ISLANDS

A major problem which is envisaged in the course of man-made climate change is sea-level rise. The global aspect of the thermal expansion of the sea water likely is reasonably well simulated by present day climate models; the variation of sea level, due to variations of the regional atmospheric forcing and of the large-scale oceanic circulation, is not adequately simulated by a global climate model because of insufficient spatial resolution. A method to infer the coastal aspects of sea level change is to use a statistical ''downscaling'' strategy: a linear statistical model is built upon a multi-year data set of local sea level data and of large-scale oceanic and/or atmospheric data such as sea-surface temperature or sea-level air-pressure. We apply this idea to sea level along the Japanese coast. The sea level is related to regional and North Pacific sea-surface temperature and sea-level air pressure. Two relevant processes are identified. One process is the local wind set-up of water due to regional low-frequency wind anomalies; the other is a planetary scale atmosphere-ocean interaction which takes place in the eastern North Pacific.

Assessing the potential of VEGETATION sensor data for mapping snow and ice cover: a Normalized Difference Snow and Ice Index

The VEGETATION (VGT) sensor in SPOT 4 has four spectral bands that are equivalent to Landsat Thematic Mapper (TM) bands (blue, red, near-infrared and mid-infrared spectral bands) and provides daily images of the global land surface at a 1-km spatial resolution. We propose a new index for identifying and mapping of snow ice cover, namely the Normalized Difference Snow/Ice Index (NDSII), which uses reflectance values of red and mid-infrared spectral bands of Landsat TM and VGT. For Landsat TM data, NDSII is calculated as NDSIITM =(TM3 -TM5)/(TM3 +TM5); for VGT data, NDSII is calculated as NDSIIVGT =(B2- MIR)/(B2 + MIR). As a case study we used a Landsat TM image that covers the eastern part of the Qilian mountain range in the Qinghai-Xizang (Tibetan) plateau of China. NDSIITM gave similar estimates of the area and spatial distribution of snow/ice cover to the Normalized Difference Snow Index (NDSI=(TM2-TM5)/(TM2+TM5)) which has been proposed by Hall et al. The results indicated that the VGT sensor might have the potential for operational monitoring and mapping of snow/ice cover from regional to global scales, when using NDSIIVGT.

利用台阵面波资料研究华北克拉通北缘燕山褶皱带及其邻区的地壳与上地幔结构

The continent of eastern China, especially the North China Craton (NCC), has endured intensive tectonic renovation during Mesozoic and Cenozoic, with the presence of widespread magmatism, high heat flow and development of large sedimentary basins and mountain ranges. The cratonic lithosphere of the region has been destroyed remarkably, which is characterized by not only a significant reduction in thickness but also complex modifications in physical and chemical properties of the lithosphere. As for the tectonic regime controlling the evolution of the NCC, various models have been put forward, including the impingement of mantle plumes (“mushroom cloud” model), the collision of south China block and north China block, the subduction of the Pacific plate, etc. Lithosphere delamination and thermal erosion were proposed as the two end-member mechanisms of the lithospheric thinning. However, given the paucity of the data, deep structural evidence is currently still scarce for distinguishing and testifying these models. To better understand the deep structure of the NCC, from 2000 to the present, temporary seismic array observations have been conducted in the NCC by the Seismological Laboratory of the Institute of the Geology and Geophysics, Chinese Academy of Sciences under the North China Interior Structure Project (NCISP). Many arrays extend from the North China Craton and the off-craton regions, and traverse a lot of main tectonic boundaries. A total of more than 300 broadband seismic stations have been deployed along several profiles that traversed the major tectonic units within the craton’s interior, at the boundary areas and in the neighboring off-craton regions. These stations recorded abundant high-quality data, which provides an unprecedented opportunity for us to unravel the deep structural features of the NCC using seismological methods. Among all the seismological methods, the surface wave method appears to be an efficient and widely adopted technique in studying the crustal and upper mantle structures. In particular, it can provide the absolute values of S-wave velocity that are difficult to obtain with other methods. Benefiting from the deployment of dense seismic arrays, progresses have been made in improving the spatial resolution of surface wave imaging, which makes it possible to resolve the fine-scale velocity structures of the crust and upper mantle based on surface wave analysis. Meanwhile, the differences in the S-wave velocities derived from Rayleigh and Love wave data can provide information on the radial anisotropy beneath the seismic arrays. In this thesis, using the NCISP-III broadband data and based on phase velocity dispersion analysis and inversion of fundamental mode Rayleigh and Love waves, I investigated the lateral variations in the S-wave velocity structure of the crust and uppermost mantle beneath the Yanshan Belt and adjacent regions at the northeastern boundary of the NCC. Based on the constructed structural images, I discussed possible deep processes of the craton destruction in the study region.

滑坡泥石流信息遥感获取与空间预测

On the issue of geological hazard evaluation（GHE）, taking remote sensing and GIS systems as experimental environment, assisting with some programming development, this thesis combines multi-knowledges of geo-hazard mechanism, statistic learning, remote sensing (RS), high-spectral recognition, spatial analysis, digital photogrammetry as well as mineralogy, and selects geo-hazard samples from Hong Kong and Three Parallel River region as experimental data, to study two kinds of core questions of GHE, geo-hazard information acquiring and evaluation model. In the aspect of landslide information acquiring by RS, three detailed topics are presented, image enhance for visual interpretation, automatic recognition of landslide as well as quantitative mineral mapping. As to the evaluation model, the latest and powerful data mining method, support vector machine (SVM), is introduced to GHE field, and a serious of comparing experiments are carried out to verify its feasibility and efficiency. Furthermore, this paper proposes a method to forecast the distribution of landslides if rainfall in future is known baseing on historical rainfall and corresponding landslide susceptibility map. The details are as following: (a) Remote sensing image enhancing methods for geo-hazard visual interpretation. The effect of visual interpretation is determined by RS data and image enhancing method, for which the most effective and regular technique is image merge between high-spatial image and multi-spectral image, but there are few researches concerning the merging methods of geo-hazard recognition. By the comparing experimental of six mainstream merging methods and combination of different remote sensing data source, this thesis presents merits of each method ,and qualitatively analyzes the effect of spatial resolution, spectral resolution and time phase on merging image. (b) Automatic recognition of shallow landslide by RS image. The inventory of landslide is the base of landslide forecast and landslide study. If persistent collecting of landslide events, updating the geo-hazard inventory in time, and promoting prediction model incessantly, the accuracy of forecast would be boosted step by step. RS technique is a feasible method to obtain landslide information, which is determined by the feature of geo-hazard distribution. An automatic hierarchical approach is proposed to identify shallow landslides in vegetable region by the combination of multi-spectral RS imagery and DEM derivatives, and the experiment is also drilled to inspect its efficiency. (c) Hazard-causing factors obtaining. Accurate environmental factors are the key to analyze and predict the risk of regional geological hazard. As to predict huge debris flow, the main challenge is still to determine the startup material and its volume in debris flow source region. Exerting the merits of various RS technique, this thesis presents the methods to obtain two important hazard-causing factors, DEM and alteration mineral, and through spatial analysis, finds the relationship between hydrothermal clay alteration minerals and geo-hazards in the arid-hot valleys of Three Parallel Rivers region. (d) Applying support vector machine (SVM) to landslide susceptibility mapping. Introduce the latest and powerful statistical learning theory, SVM, to RGHE. SVM that proved an efficient statistic learning method can deal with two-class and one-class samples, with feature avoiding produce ‘pseudo’ samples. 55 years historical samples in a natural terrain of Hong Kong are used to assess this method, whose susceptibility maps obtained by one-class SVM and two-class SVM are compared to that obtained by logistic regression method. It can conclude that two-class SVM possesses better prediction efficiency than logistic regression and one-class SVM. However, one-class SVM, only requires failed cases, has an advantage over the other two methods as only "failed" case information is usually available in landslide susceptibility mapping. (e) Predicting the distribution of rainfall-induced landslides by time-series analysis. Rainfall is the most dominating factor to bring in landslides. More than 90% losing and casualty by landslides is introduced by rainfall, so predicting landslide sites under certain rainfall is an important geological evaluating issue. With full considering the contribution of stable factors (landslide susceptibility map) and dynamic factors (rainfall), the time-series linear regression analysis between rainfall and landslide risk mapis presented, and experiments based on true samples prove that this method is perfect in natural region of Hong Kong. The following 4 practicable or original findings are obtained: 1) The RS ways to enhance geo-hazards image, automatic recognize shallow landslides, obtain DEM and mineral are studied, and the detailed operating steps are given through examples. The conclusion is practical strongly. 2) The explorative researching about relationship between geo-hazards and alteration mineral in arid-hot valley of Jinshajiang river is presented. Based on standard USGS mineral spectrum, the distribution of hydrothermal alteration mineral is mapped by SAM method. Through statistic analysis between debris flows and hazard-causing factors, the strong correlation between debris flows and clay minerals is found and validated. 3) Applying SVM theory (especially one-class SVM theory) to the landslide susceptibility mapping and system evaluation for its performance is also carried out, which proves that advantages of SVM in this field. 4) Establishing time-serial prediction method for rainfall induced landslide distribution. In a natural study area, the distribution of landslides induced by a storm is predicted successfully under a real maximum 24h rainfall based on the regression between 4 historical storms and corresponding landslides.

尺度匹配方法在井震联合重建和多次波衰减中的应用

Scale matching method means adjusting information with different scale to the same level. This thesis focuses on scale unification of information with different frequency bandwidth. Well-seismic cooperate inversion is an important component of reservoir geophysics; multiple prediction & subtraction is a development of multiple attenuation in recent years. The common ground of these two methods is that they both related to different frequency bandwidth unification. Well log、cross-hole seismic、VSP、3D seismic and geological information have different spatial resolution, we can decrease multi-solution of reservoir inversion and enhance the vertical and lateral resolution of the geological object by integrate those information together; Compare the predicted multiple generated by SRME with the real multiple, we find the predicted multiple convolutes at least one wavelet more, which brings frequency bandwidth difference between them. So the subtraction method also relates to multi-scale information unification. This thesis gives a method of well constrained seismic high resolution processing basing on auto gain control modulation. It uses base function method which utilizes original well-seismic match result as initial condition and processed seismic trace as initial model to extrapolate the high frequency information of the well logs to the seismic profiles. In this way we can broaden the bandwidth of the seismic and make the high frequency gain geological meaning. In this thesis we introduce the revised base function method to adaptive subtraction and verify the validity of the method using models. Key words: high frequency reconstruction, scale matching, base function, multiple, SRME prediction & subtraction

乡镇级人口统计数据空间化研究

Population data which collected and saved according to administrative region is a kind of statistical data. As a traditional method of spatial data expression, average distribution in every administrative region brings population data on a low spatial and temporal precision. Now, an accurate population data with high spatial resolution is becoming more and more important in regional planning, environment protection, policy making and rural-urban development. Spatial distribution of population data is becoming more important in GIS study area. In this article, the author reviewed the progress of research on spatial distribution of population. Under the support of GIS, correlative geographical theories and Grid data model, Remote Sensing data, terrain data, traffic data, river data, resident data, and social economic statistic were applied to calculate the spatial distribution of population in Fujian province, which includes following parts: (1) Simulating of boundary at township level. Based on access cost index, land use data, traffic data, river data, DEM, and correlative social economic statistic data, the access cost surface in study area was constructed. Supported by the lowest cost path query and weighted Voronoi diagram, DVT model (Demarcation of Villages and Towns) was established to simulate the boundary at township level in Fujian province. (2) Modeling of population spatial distribution. Based on the knowledge in geography, seven impact factors, such as land use, altitude, slope, residential area, railway, road, and river were chosen as the parameters in this study. Under the support of GIS, the relations of population distribution to these impact factors were analyzed quantificationally, and the coefficients of population density on pixel scale were calculated. Last, the model of population spatial distribution at township level was established through multiplicative fusion of population density coefficients and simulated boundary of towns. (3) Error test and analysis of population spatial distribution base on modeling. The author not only analyzed the numerical character of modeling error, but also its spatial distribution. The reasons of error were discussed.

The detection of 'soft' materials by selective energy xray transmission imaging and computer tomography

R. Zwiggelaar, C.R. Bull, M.J. Mooney and S. Czarnes, 'The detection of 'soft' materials by selective energy xray transmission imaging and computer tomography', Journal of Agricultural Engineering Research 66 (3), 203-212 (1997)