Soil physical properties change in the process of oasisization

Oasisization is a process of converting a natural desert into a man-made oasis in order to satisfy social needs under certain economical and technical conditions. This paper substitutes space for time in order to study physical property changes of oasis soil along the oasisization in about a 1,000-year period. This research focuses on providing the bases for better understanding the process of oasisization. The results show: (1) In about 1,000-year chronological scale, the bulk density and the saturated soil hydraulic conductivity of the surface layer (0-20 cm) significantly reduced with the increase of land reclamation time, while soil porosity, stability of aggregates, and silt content significantly increased. The soil bulk density of the unreclaimed filed (0 year) and the reclaimed field (about 1,000 years) in the surface layer (0-20 cm) are 1.51 g/cm3 and 1.35 g/cm3, the total porosity are 43.16% and 49.27%, the capillary porosity are 38.73% and 47.10%, the water-stable aggregate (】0.25 mm) content are 24.60% and 49.59%, the sand content are 85.42% and 61.56%, the clay content are 3.93% and 4.80%, the specific surface area are 128 cm2/g and 231 cm2/g, and the saturated hydraulic conductivity are 0.74 cm/h and 0.34 cm/h, respectively. (2) In the first 30 years of the oasis reclamation, the changes are relatively fast, and the rates of the saturated soil hydraulic conductivity, dry aggregate (】0.25 mm), water-stable aggregate (】0.25 mm) content, and specific surface area are 0.01 cm/h·yr, 0.58%/yr, 0.50%/yr, and 1.48 cm2/g yr, respectively.

FL-Online:An x-ray crystallographic web-server for atomic-scale structure analysis of biomolecule

FL-Online(http://fanlab.ac.cn) is an out-of-box modern web service featuring a user-friendly interface and simplified parameters, providing academic users with access to a series of online programs for biomolecular crystallography, including SAPI-online, OASIS-online, C-IPCAS-online and a series of upcoming software releases. Meanwhile, it is a highly scalable and maintainable web application framework that provides a powerful and flexible solution for academic web development needs. All the codes are open-source under MIT licenses in GitHub.

Why lowland riparian trees are difficult to use for streamflow reconstruction

Existing streamflow reconstructions based on tree-ring analysis mostly rely on species from upland,mainly montane areas,while lowland species(generally plain)areas are rarely used.This limits the understanding of streamflow change history in the lowlands,which is an important basis for water resource management.This study focused on Populus euphratica stands located along the main stream,eastern and western tributaries in the lower reaches of the Heihe River basin(HRb),in arid northwestern China.We investigated how streamflow regulation interferes with ripar-ian trees in lowlands when they used for streamflow recon-struction.Tree-ring width chronologies were developed and analyzed in conjunction with meteorological and hydrologic observation data.The results show streamflow regulation leads in sharp fluctuations in the streamflow allocation between the eastern tributaries and western tributaries.This resulted in instability of the correlation between streamflow at the two tributaries and at the Zhengyixia hydrologic station,with corresponding fluctuations in radial growth of poplar trees on the banks of the two tributaries and at the station.Streamflow regulation altered the natural patterns of seasonal streamflow below the station,changing the time window of poplar response.This study provides useful insight into tree-ring width based streamflow reconstruction in the lowlands.

UPLC-MS/MS测定特殊医学用途配方乳粉中姜黄素类化合物

建立基于通过式固相萃取净化检测特殊医学用途配方乳粉中姜黄素的超高效液相色谱串联质谱检测方法。样品经80%乙腈提取,通过Oasis PRiME HLB固相萃取柱净化后,以乙腈-0.1%甲酸溶液作为流动相,在acquity UPLC HSS T_(3)色谱柱上进行梯度洗脱,经超高效液相色谱仪进行分离后,通过电喷雾正离子模式电离,多反应监测模式进行检测分析,外标法定量。对目标物进行稳定性研究,对样品中目标物提取、净化方式、色谱分离条件、质谱条件等关键因素进行了优化。结果表明,3种姜黄素类化合物在25~2 500 ng/mL范围内线性关系好,相关系数高于0.99,加标回收率在87.9%~102.8%之间,精密度在1.31%~4.94%之间,3种姜黄素类化合物的检出限为10μg/kg,定量限为25μg/kg。该方法定性定量结果准确、稳定性好、灵敏度高,能够对特殊医学用途配方乳粉中姜黄素类化合物进行定性分析与定量检测。

Assessment of vegetation cover changes and the contributing factors in the Al-Ahsa Oasis using Normalized Difference Vegetation Index(NDVI)

The abandonment of date palm grove of the former Al-Ahsa Oasis in the eastern region of Saudi Arabia has resulted in the conversion of delicate agricultural area into urban area.The current state of the oasis is influenced by both expansion and degradation factors.Therefore,it is important to study the spatiotemporal variation of vegetation cover for the sustainable management of oasis resources.This study used Landsat satellite images in 1987,2002,and 2021 to monitor the spatiotemporal variation of vegetation cover in the Al-Ahsa Oasis,applied multi-temporal Normalized Difference Vegetation Index(NDVI)data spanning from 1987 to 2021 to assess environmental and spatiotemporal variations that have occurred in the Al-Ahsa Oasis,and investigated the factors influencing these variation.This study reveals that there is a significant improvement in the ecological environment of the oasis during 1987–2021,with increase of NDVI values being higher than 0.10.In 2021,the highest NDVI value is generally above 0.70,while the lowest value remains largely unchanged.However,there is a remarkable increase in NDVI values between 0.20 and 0.30.The area of low NDVI values(0.00–0.20)has remained almost stable,but the region with high NDVI values(above 0.70)expands during 1987–2021.Furthermore,this study finds that in 1987–2002,the increase of vegetation cover is most notable in the northern region of the study area,whereas from 2002 to 2021,the increase of vegetation cover is mainly concentrated in the northern and southern regions of the study area.From 1987 to 2021,NDVI values exhibit the most pronounced variation,with a significant increase in the“green”zone(characterized by NDVI values exceeding 0.40),indicating a substantial enhancement in the ecological environment of the oasis.The NDVI classification is validated through 50 ground validation points in the study area,demonstrating a mean accuracy of 92.00%in the detection of vegetation cover.In general,both the user’s and producer’s accuracies of NDVI classification are extremely high in 1987,2002,and 2021.Finally,this study suggests that environmental authorities should strengthen their overall forestry project arrangements to combat sand encroachment and enhance the ecological environment of the Al-Ahsa Oasis.

固相萃取-超高效液相色谱-串联质谱法测定菊花中15种吡咯里西啶生物碱毒素

目的建立超高效液相色谱-串联质谱法(ultra performance liquid chromatography-tandem mass spectrometry,UPLC-MS/MS)测定菊花中15种吡咯里西啶生物碱毒素含量的分析方法。方法样品中吡咯里西啶生物碱毒素采用0.1 mol/L硫酸水溶液提取,通过Oasis PRiME MCX固相萃取小柱净化,采用UPLC-MS/MS进行分析。采用Acquity UPLC BEH C18色谱柱分离,以0.1%甲酸水-甲醇溶液为流动相进行梯度洗脱,电喷雾离子源正离子电离,多反应离子监测模式监测,外标法定量。结果15种吡咯里西啶生物碱毒素在一定浓度范围内线性关系良好,相关系数(r2)均大于0.999;定量限为0.50~10.00μg/kg,检出限为0.15~3.00μg/kg;阴性样品的加标回收率为82.8%~92.4%,相对标准偏差为2.1%~4.9%(n=5)。结论该方法准确度和精密度高,耗时短,能同时测定多种菊花样品中的多种吡咯里西啶生物碱毒素含量。

超高效液相色谱联质语质中多肽类抗生素

使用0.45μm微孔滤膜过滤水样,然后加入Na2EDTA盐,除去部分金属离子,再调节pH值为3,使用Oasis HLB固相萃取柱富集净化,用5 mL、0.1%的甲酸甲醇和5 mL甲醇洗脱,经氮吹浓缩,以0.1%的甲酸乙腈和0.1%的甲酸水溶液为流动相,采用超高效液相色谱-串联质谱检测多肽类抗生素。检测结果表明,在标准曲线浓度范围内,11种多肽类抗生素线性关系r2均大于0.998,检测限均低于1 ng/L,进行低、中、高浓度加标,平均加标回收率在77.7%~98.1%之间,相对标准偏差在1.5%~14.2%之间。该方法操作简便、测试时间短、准确度和精确度好、检出限低,可以同时测定水质中11种多肽类抗生素。

基于Oasis Montaj平台的航空物探数据处理软件系统

在深入研究Oasis Montaj平台特点的基础上,对已有的处理功能进行移植、优化,并开发了新的功能,集成为航空物探数据处理软件系统。这里就系统的整体架构、主要功能及其实现方法进行了详细介绍。通过大量的数据处理证明了该系统具有集成度高、实用性强、运行效率高、稳定性强、易操作、容错性强等诸多优势,能极大地提高数据处理的效率和质量。

产时限制会阴切开对母儿的近期影响

目的:观察头位初胎阴道产时限制会阴切开,对产妇及新生儿近期指标的影响,以评估产时常规会阴切开对于母儿安全是否必要。方法:2011年我院头位足月阴道初产妇932例,产时尽量不做会阴切开;2009年11月至2010年10月阴道产时常规会阴切开,共727例。比较两组产妇近期指标(会阴裂伤、新生儿窒息、产后排尿及产程)情况。结果:限制会阴切开组与常规组相比,会阴切开率分别为35.0%与78.4%,严重会阴裂伤率、新生儿窒息率、产后导尿率与产程时间等指标两组间无显著差异,限制切开组产后2 h出血量明显少于常规组。结论:限制会阴切开不增加严重会阴裂伤与新生儿窒息率、不延长产程、减少产时出血量,头位初胎自然产时没有必要常规会阴切开。

HLB固相萃取技术HPLC法测定地表水中9种酚类化合物

酚类化合物是环境水中主要污染物之一,水资源污染问题严重影响了人们的身体健康。研究水中酚类化合物的测定方法有着重要意义,因此本实验建立了高效液相色谱法测定水体中9种酚类化合物分析方法。本方法相比传统其它检测方法选取Oasis PRiME HLB固相萃取柱对水样净化富集,甲醇洗脱,定容过滤后通过高效液相色谱分析测定。外标法定量,9种酚类化合物苯酚、对硝基酚、4-氯间酚、邻氯酚、邻硝基酚、2,4-二甲酚、2,4-二氯酚、2,4,6-三氯酚和五氯酚的检出限为0.005~0.01μg/mL,工作曲线线性相关系数0.9992~0.9998,样品回收率范围86.5~92.4%,相对标准偏差RSD为0.8~2.2%,本方法分离效能高、检测灵敏,选择性强,适用于地表水中酚类化合物的测定。

利用正交位移测量系统进行六自由度并联机构参数标定

为了简化六自由度并联机构的参数标定过程,提高标定效率,降低标定成本,提出了基于正交位移测量系统的位姿测量装置及方法。首先,研究了该装置的位姿解算方法,利用空间解析几何的方法,求解其运动学正解与逆解。其次,利用微小位移合成法,建立了并联机构及正交位移测量系统组合体的误差模型。然后,基于误差模型,构建了组合体参数误差辨识的最优化问题数学模型,其中,传感器示值的平方和最小为目标函数,组合体的结构参数误差为设计变量。最后,利用正交位移测量系统对六自由度并联机构位姿进行测量,利用OASIS奥希思软件直接搜索出参数误差最优解,将其补偿到并联机构控制系统中,完成并联机构的参数标定。标定前后位姿误差对比表明:最大位置误差降低了58%~96%,最大姿态误差降低了92%~97%。利用正交位移测量系统进行并联机构参数标定,不仅可有效提升并联机构的定位精度,还可有效简化标定工作,提升标定效率,降低标定成本。

Sustainable Development of Agriculture in Northwestern Ecologically Fragile Desert Oasis——A case study of Guazhou County of Gansu Province

Guazhou County of Gansu Province is a typical ecological fragile area lying in the transition area of desert and oasis.The development of its agricultural economy is highly dependent on natural resources and environment.Contradiction of resources characterized agriculture and the fragile ecological environment has become one of the main barriers to log the impact of local agriculture to achieve sustainable development.Aiming at fragile ecological environment and limiting factors of agricultural sustainable development,thoughts and countermeasures of realizing agricultural sustainable development have been proposed.

基于MAPGIS的剖面平面图生成系统

近年来,航空物探项目主要是使用Oasis montaj软件完成数据处理工作,最终提交的成果图件采用MapGIS地理信息系统软件绘制。由于两种软件系统采用的数据格式及兼容性不尽相同,因此采用Visual Basic编程语言编制专用程序,实现两种软件系统数据格式的接口,同时解决MapGIS中剖面平面图的绘制问题。这一问题的解决既发挥了Oasis montaj软件强大的数据处理功能,又充分利用MapGIS软件成熟的绘图功能,同时在项目实施过程中大大提高了数据处理和成果图件绘制的效率,取得了较好的应用效果。

Comprehensive Evaluation of Environmental Effects from Land Change in Hotan Oasis,Xinjiang

[Objective] This study aimed to evaluate the environmental effects coming from land changes in Hotan oasis during 1980-2010. [Method] Based on the Driving Force-State-Response model, expert weight method and entropy method were used to determine weight, and then the composite indexes of environmental effects （CIE for short） were calculated. [Result] During the period from 1980 to 2010, CIE had presented a rising trend whether expert weight method or entropy method in the study area, while the CIE presents downtrend basically in lower reaches. [Conclu- sion] It was the arable land expansion in middle reaches that led to serious land degradation in lower reaches, and may endanger ecosystem safety in Hotan River green corridor. Therefore, it is suggested that the agricultural land use should be restructured, such as reducing the sown areas of some crops with large amount of water consumption. Meanwhile, the effective measures should be taken to distribute water resources and utilize them reasonably. In addition, the oasis-desert ecotone, as well as the groundwater resources, should be also protected.

Assessment of Ecosystem Services Value in Hotan Oasis, Xingjiang

[Objective] The study aimed to assess the ecosystem services value in Hotan Oasis, Xingjiang. [Method] The visual interpretation method was adopted to process TM/ETM＋ images based on field investigation in Hotan Oasis. These inter- pretation data, along with two periods of land use data, were reclassified to farm- land, forest, grassland and so on. Then, the ecosystem services value was calculat- ed and analyzed. [Result] Analysis indicated that the ecosystem services value had been increased by 30.44x108 Yuan （16.51%） in the study area during 1980-2010, which can be explained by the increase of glacier and snowfield distributed in the south mountain with the increase of annual precipitation. At the same time, the con- tribution rate of grassland to ecosystem services value had been decreased as a result of degradation of grassland and occupation from farmland. For the whole basin, the increase of ecosystem services value came from the upper reaches, while the ecosystem services value had been reduced in the middle and lower reaches. In the middle reaches, the reduction came mainly from wetland （-1.83x10s Yuan）, waters （-1.68x10s Yuan）, forest （-0.86x108 Yuan） and grassland （-0.80x108 Yuan）. But in the lower reaches, the ecosystem services values of waters, grassland and forest were -0.61 x108 Yuan, -0.24x108 Yuan, and -0.07x10s Yuan, respectively. [Conclusion] If some effective policies, such as the implementation of returning farm- land to forest and ceasing from farming to grazing, would be taken, the ecosystem degradation can be constrained and reversed in the northwest arid region.

OASIS程序的开发与应用

全面描述了对来自法国原子能委员会 (简称CEA)的快堆系统安全分析程序OASIS的引进和开发工作 ,并在此基础上介绍了该程序在中国实验快堆 (ChinaExperimentalFastReactor,简称CEFR)初步安全分析报告中对主给水管道断裂事故的分析计算。

自定义坐标系的建立及其坐标变换实现

大地基准(含数学椭球体)和投影方式的组合形成多种投影坐标系。地质勘查工作者常遇到坐标转换问题和建立自定义坐标问题,尤其是当我国北京54坐标系和西安80坐标系地质数据的GIS化时。GIS软件已经成为地质勘查的基本工具,而地质数据GIS化的第一步就是建立坐标系统。本文论述了如何使用Map Info和GeosoftOasis MontajTM两种常见地质勘查GIS软件建立自定义坐标,主要是如何在该两个软件中构建自定义大地基准(datum),并且给出了如何使用两个软件进行坐标变换的步骤。

CEFR非对称运行工况的研究

为研究中国实验快堆(CEFR)非对称运行工况,通过快堆系统安全分析程序OASIS及堆芯子通道分析程序COBRA对CEFR单环路运行时堆内的温度以及流量进行了计算。结果表明,CEFR在单环路运行,完好环路一、二次钠泵转速为500r/min,且事故环路一次钠泵逆止阀开启时,堆芯最多开启在14%的功率水平,以确保反应堆处于安全状态。

中国实验快堆1台一回路泵切除试验计算模拟与分析

为检验中国实验快堆(CEFR)发生1台一回路泵切除事件时的安全性,拟在CEFR上进行试验验证。为确保试验的安全性,利用系统分析程序OASIS对试验过程进行了模拟,并对试验可能存在的风险进行了分析。计算结果表明:按照试验步骤进行操作不会对反应堆安全构成威胁;试验初期存在一些风险,源于主热传输系统各回路的流量不匹配问题,可能会对设备产生较大的热冲击。

Effects of Different Irrigation Amounts on Wheat Growth in Arid Oasis Area

[Objective] The study was conducted to analyze the effects of different irrigation amount on the growth of wheat in arid oasis area and determine effective use measures and reasonable irrigation indices of water in farmland under arid oasis environment,so as to provide reference for the development and management of water-saving technology.[Method] Spring wheat in different growth periods was irrigated for four times.The leaf area index,dry matter content,1 000-grain weight of wheat in different growth peri...