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针对化探样品批量大,元素多,检出限低等特点,采用水平电极撒料法,对化探样中多种微量元素进行了光谱定量分析.将样品与缓冲剂1:1混匀,采用W-100光栅摄谱仪(光栅刻线1200条/毫米,二级光谱)进行水平撒样摄谱,谱板经暗室处理后,在东德GFE760μ测微光度计上用P标尺测光,以△P-logc绘制工作曲线,查出含量.本法采用了特制的撒样漏斗,改善了下料的均匀性,提高了分析精度;以Ge和Pd作内标消除工作条件变化对谱线强度的影响;同时还试选了SiO2:C:Na2SO4＝61:30:9的混合物作缓冲剂,提高了弧烧的稳定性,获得了较高的再现性.本文还采用了一种单元素线减光器对Ag3382.9进行减光,使Ag的测定上限由5×10-6提高到30×10-6.本法操作简便快速,成本较低,一次可测定Ag、W、Mo、Sn、Bi、Cu、Pb、Zn、Ni、Co、Cr等多种元素,检出限为Ag 0.03×10-6,W 0.5×10-6,Mo0.05×10-6,Sn 0.4×10-6,Pb 1×10-6,Zn 3×10-6,Cu 0.5×10-6,Bi 0.1×10-6,Ni 0.3×10-6,Co 0.3×10-6,Cr 1×10-6,基本上达到了化探普查找矿定量分析的要求. 相似文献
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当前,中国粮油企业的生存与发展已与世界粮油经济的发展息息相关。无论是粮油企业全面亏损的2004年,还是粮油价格大起大落的2008年,世界其他各国粮油政策和价格的变化均对中国的粮油产业发展造成了很大的影响。全面了解国际粮油发展新动向、掌握世界粮油食品发展新方向,从宏观上为企业找到准确定位,是每位粮油企业家、每位粮油人都必须具备的。正所谓知己知彼,百战不殆,希望以下这些国际前沿信息能为您带来收获。 相似文献
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为了快速、准确地检测土壤中多种重金属元素,建立一种王水消解同时测定土壤中Cu,Zn,Ni,Cr,Pb,Cd的方法.选取8种具有广泛代表性的土壤标准物质对王水消解法进行考察,结合土壤标准物质标准值,通过大量试验数据对该方法做出全面评价. 相似文献
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砀山县丰产农机服务专业合作社位于安徽省宿州市砀山县朱楼镇朱楼村,成立于2015年5月13日。合作社目前占地1.33 hm^2(20余亩),拥有成员200余人,拖拉机40多台,收割机18台,灌溉机械14套,植保飞机80多架,烘干机6组,配套农具230多台(套),机械资产达到1 200余万元。 相似文献
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J. R. Philip 《Irrigation Science》1987,8(2):101-114
Summary We study the effect of surface resistance r (whether of monolayers on free water or plant diffusive resistance) on evaporation rate, energy balance, and microclimate, under advective conditions. We use power-law representations of the vertical profiles of mean windspeed and eddy diffusivity, and exploit two known similarity solutions, one for a step-function change of surface concentration, and the other for a step-function change of surface flux density. To a very close approximation, these two contrasting canonical advective problems yield the same (spatially variable) boundary layer transfer coefficient expressing the ratio of the surface flux perturbation to the surface concentration perturbation. Adopting this coefficient reduces the (spatially variable) surface energy balance for the advective boundary layer with surface resistance to a quadratic equation, with the solution yielding the fetch distances x at which the surface temperature assumes a given value To. With To (x) established thus, the other significant properties of the boundary layer follow simply and directly.The results reveal the profound influence of r, especially at small x. As boundary layer atmospheric resistance increases with x, r becomes relatively less important. It can be regarded as primarily reducing advective effects. Antievaporation films thus work best on small water surfaces in arid surroundings, but are less effective the larger the water body and the moister the surrounds. If leaf temperatures are not limiting, increasing r has greatest effect for small vegetated areas in an arid environment, but may not be optimal for extensive continuous monocultures. Control of surface resistance offers means of manipulating microclimate, for example when arid landscapes are watered for this purpose. The exploratory nature of this investigation, and its many limitations, are stressed. 相似文献
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E. Owen 《Agricultural Systems》1983,11(1):66
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《Agricultural Systems》2002,74(1):141-177
FARMSCAPE (Farmers', Advisers', Researchers', Monitoring, Simulation, Communication And Performance Evaluation) is a program of participatory research with the farming community of northeast Australia. It initially involved research to explore whether farmers and their advisers could gain benefit from tools such as soil characterisation and sampling, climate forecasts and, in particular, simulation modelling. Its current focus is facilitating the implementation of commercial delivery systems for these same tools in order to meet industry demand for their access. This paper presents the story of what was done over the past decade, it provides performance indicators of impact, it reflects on what was learnt over this period and it outlines where this research is likely to head in the future.Over the past 10 years, the FARMSCAPE team employed a Participatory Action Research approach to explore whether farmers could value simulation as a decision support tool for managing their farming system and if so, could it be delivered cost-effectively. Through farmer group engagement, on-farm trials, soil characterisation, monitoring of crops, soils and climate, and sessions to apply the APSIM systems simulator, FARMSCAPE represented a research program on decision support intervention. Initial scepticism by farmers and commercial consultants about the value of APSIM was addressed by testing its performance both against measured data from on-farm trials and against farmers' experiences with past commercial crops. Once this credibility check was passed, simulation sessions usually evolved into participants interactively inquiring of the model the consequence of alternative management options. These ‘What if’ questions using APSIM were contextualised using local climate and soil data and the farmer's actual or proposed management rules.The active participation of farmers and their advisers, and working in the context of their own farming operations, were the key ingredients in the design, implementation and interpretation of the FARMSCAPE approach to decision support. The attraction of the APSIM systems simulator to farmers contemplating change was that it allowed them to explore their own system in a manner equivalent to learning from experience. To achieve this, APSIM had to be credible and flexible. While direct engagement of farmers initially enabled only a limited number of beneficiaries, this approach generated a commercial market for timely and high quality interactions based on soil monitoring and simulation amongst a significant sector of the farming community. Current efforts are therefore focused on the training, support and accreditation of commercial agronomists in the application of the FARMSCAPE approach and tools.The FARMSCAPE approach to decision support has come to represent an approach to guiding science-based engagement with farm decision making which is being tested nationally and internationally. 相似文献
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一株中温厌氧纤维素降解细菌的分离、鉴定及其系统发育分析 总被引：5，自引：1，他引：4
以树中心湿木为样品,富集分离获得一株具有较强纤维素分解能力的中温厌氧纤维素降解细菌CSZM-6.分离菌株革兰氏染色阴性,直杆或稍弯曲杆状,多数单生,少数成对或成串,部分菌体产芽孢.菌体大小为0.5μm×1.7～2.6μm,严格厌氧,最适生长温度40℃,最适pH6.5,以葡萄糖为底物时倍增时间8.0h.分离菌株在纤维素粉固体培养基中培养3周后,菌落为圆形或不规则形状,产黄色素,直径为0.5～4.0mm,水解圈直径为2.0～18.0mm.分离菌株不仅能利用纤维素、纤维二糖、葡萄糖等碳水化合物,还能利用未经处理的报纸、水稻秸秆、麦秆.发酵纤维素产乙醇、乙酸、H2、CO2、甲酸、丙酸、乳酸.在菌株CSZM-6的纤维素酶系中,只存在外切-β-1,4-葡聚糖酶(C1酶)和内切-β-1,4-葡聚糖酶(Cx酶)两种组分,最适温度分别为40℃和45℃.通过16SrDNA序列分析表明,菌株CSZM-6为梭菌属Clostridium,与C. papyrosolvens具有99.6%的相似性. 相似文献
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深化改革加强管理抓住机遇加快农村水利事业发展 总被引：2，自引：2，他引：2
冯广志 《中国农村水利水电》2002,(2):1-4
12001年工作回顾2001年1月份水利部在上海召开了全国水利工作会议,研究和部署新世纪初、重点是“十五”期间的工作。我代表农村水利司在会上作了发言,提出了今后几年农村水利工作的总体思路、布局、重点、对策措施等。发言稿经过翟浩辉副部长审阅修改,原稿登在2001年第1期《中国农村水利水电》上。回顾2001年的工作,我们是紧紧围绕贯彻党中央、国务院对新形势下农业、农村、农民工作的一系列指示精神和部党组关于新时期调整治水思路的具体部署开展的。重点抓了“灌区改造节水灌溉增效工程”、“农村饮水解困工程”、“雨水集蓄富民工程”、“农村水利现代化示范工程”等四大工程的实施,其中又把节水增效、饮水解困作为重中之重。主要开展了以下工作: 相似文献
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本文利用虚拟现实/混合现实/增强现实/数字孪生等主流多媒体交互技术融入农业生产、生态、生活场景中,从北京都市型现代农业发展进程中的设施农业调控、会展农业体验、休闲农业观光、现代农业展示的各方面入手,通过获取农业物联网数据、农业园区场景数据、农作物生长点云数据等多种信息化数据,构建基于物联网实时数据的交互式虚拟休闲农业园区平台,基于平台软件,根据不同的实际需求、环境条件,配置研发满足政府、专家、市民、农民、学生等受众对于智慧化农事活动体验、农业科普知识传播、农业园区展示规划、农业景观重构展现等要求的体验设备,为设施农园、休闲农庄、农业机构等提供完整的多媒体农业信息化交互体验解决方案,达到节本增效、增收致富、知识普及、休闲观光、提升信息化水平的目的。 相似文献
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《Agricultural Systems》2005,83(3):331-332
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Simulation of transpiration, drainage, N uptake, nitrate leaching, and N uptake concentration in tomato grown in open substrate 总被引：3，自引：0，他引：3
M. Gallardo J.S. Rodríguez M.D. Fernández J.J. Magán 《Agricultural Water Management》2009,96(12):1773-1784
Free-drainage or “open” substrate system used for vegetable production in greenhouses is associated with appreciable NO3− leaching losses and drainage volumes. Simulation models of crop N uptake, N leaching, water use and drainage of crops in these systems will be useful for crop and water resource management, and environmental assessment. This work (i) modified the TOMGRO model to simulate N uptake for tomato grown in greenhouses in SE Spain, (ii) modified the PrHo model to simulate transpiration of tomato grown in substrate and (iii) developed an aggregated model combining TOMGRO and PrHo to calculate N uptake concentrations and drainage NO3− concentration. The component models simulate NO3−-N leached by subtracting simulated N uptake from measured applied N, and drainage by subtracting simulated transpiration from measured irrigation. Three tomato crops grown sequentially in free-draining rock wool in a plastic greenhouse were used for calibration and validation. Measured daily transpiration was determined by the water balance method from daily measurements of irrigation and drainage. Measured N uptake was determined by N balance, using data of volumes and of concentrations of NO3− and NH4+ in applied nutrient solution and drainage. Accuracy of the two modified component models and aggregated model was assessed by comparing simulated to measured values using linear regression analysis, comparison of slope and intercept values of regression equations, and root mean squared error (RMSE) values. For the three crops, the modified TOMGRO provided accurate simulations of cumulative crop N uptake, (RMSE = 6.4, 1.9 and 2.6% of total N uptake) and NO3−-N leached (RMSE = 11.0, 10.3, and 6.1% of total NO3−-N leached). The modified PrHo provided accurate simulation of cumulative transpiration (RMSE = 4.3, 1.7 and 2.4% of total transpiration) and cumulative drainage (RMSE = 13.8, 6.9, 7.4% of total drainage). For the four cumulative parameters, slopes and intercepts of the linear regressions were mostly not statistically significant (P < 0.05) from one and zero, respectively, and coefficient of determination (r2) values were 0.96-0.98. Simulated values of total drainage volumes for the three crops were +21, +1 and −13% of measured total drainage volumes. The aggregated TOMGRO-PrHo model generally provided accurate simulation of crop N uptake concentration after 30-40 days of transplanting, with an average RMSE of approximately 2 mmol L−1. Simulated values of average NO3− concentration in drainage, obtained with the aggregated model, were −7, +18 and +31% of measured values. 相似文献
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《Agricultural Systems》2005,83(1):110-111