陕西果树花期低温冻害特征及防御对策   总被引：20，自引：2，他引：18  

李健  刘映宁  李美荣  李艳莉 《气象科技》2008,36(3):318-322

利用陕西省30个苹果(梨)基地县气象站1961～2000年3～5月气象资料及2001～2006年9个苹果(梨)基地县气象站物候观测资料,采用气象统计、田间试验和灾害调查相结合的方法,确定了不同等级果树花期冻害的预警指标:严重低温冻害(TD≤-2℃)、低温冻害(-2℃相似文献   

迁移学习支持下的高分影像积云提取方法研究     

楚彬  郝建明  华亮春  靳文凭  李政 《测绘与空间地理信息》2020,(3):93-96

针对传统影像质量检查工作中积云提取存在人工作业量大、操作烦琐等问题,本文通过引入迁移学习机制,将已有数据集训练过程中得到的神经网络参数迁移到解译模型构建中,提出了一种适用于积云的自动提取方法。本文以湖南省不动产统一登记基础数据为实验对象进行了实验,结果表明,本文方法的浓积云提取总体精度可以达到90%以上,淡积云提取的总体精度可以达到87.3%,表明本文研究可用于高分影像积云自动提取。  相似文献   

基于地面三维激光扫描两种模型重建技术     

罗寒  王建强 《测绘与空间地理信息》2015,(7):63-65

地面三维激光扫描技术可以快速地采集目标物表面海量点云数据,利用点云能够准确重建空间三维模型。本文基于完全不同形状的两组点云数据,分别采用三角网格法和提取特征线法两种不同建模方法进行实验,完成模型重建,取得较好的效果。同时探讨了点云处理和模型重建的关键问题,为工程生产提供借鉴。  相似文献   

利用微波功率传感器判断新一代天气雷达故障     

胡帆  柴秀梅  王凌震  周红根 《气象》2011,37(8):1042-1044

近年来,以平面掺杂势垒二极管为核心构成的微波功率传感器与小功率计配合,能实现对微波功率的高速、高精度和连续测量,广泛应用于天气雷达等高频设备信号功率的测量。文章详细阐述了微波功率传感器的特性和电路原理,以及该传感器与小功率计的连接、设置和使用方法。并以在CINRAD/SA雷达发射机、接收机中两个典型故障检修事例,论述了微波功率传感器在天气雷达上的应用。  相似文献   

坛紫菜氨基酸提取工艺影响条件的优化与分析     

史修周  陈昌生  谢潮添  纪德华  徐燕  赵玲敏  张元  周巍巍 《台湾海峡》2011,30(1):132-137

以坛紫菜（Porphyra haitanensis）为实验材料,采用盐酸水解法和浸提法,以日立L-8900型高速全自动氨基酸分析仪为测定仪器,分别研究了坛紫菜总氨基酸（TAA）和游离氨基酸（FAA）在提取过程中各条件的不同水平对提取结果的影响.实验结果表明：（1）利用正交设计L9（34）对影响TAA提取的4个条件（藻体质量、稀释倍数、干燥温度、空白值）在3个水平上进行优化实验,藻体质量、稀释倍数对测定结果影响显著,干燥温度影响不显著;通过实验筛选出各条件的最佳水平为：藻体质量为0.050 0g,稀释3倍,干燥温度为60℃.（2）利用正交设计L16（45）对影响FAA测定的5个条件（藻体质量、提取液、提取温度、提取时间、空白值）在4个水平上进行优化实验,结果表明藻体质量、提取液、提取温度、提取时间的不同水平对测定结果均有显著影响,其中藻体质量对结果的影响最大;通过实验筛选出各条件的最佳水平为：藻体质量为0.010 0 g,提取液为去离子水,提取温度为60℃,提取时间为4 h.  相似文献   

S‐Doped Magnetic Mesoporous Carbon for Efficient Adsorption of Methyl Orange from Aqueous Solution     

Jiangyan Xu  Shiman Zhai  Bo Zhu  Jingxin Liu  Aimin Lu  Hongmei Jiang 《洁净——土壤、空气、水》2021,49(1)

A simple and rapid soft‐templating coupled with one‐pot solvent thermal method is developed to synthesize S‐doped magnetic mesoporous carbon (S‐doped MMC). In this method, phenolic resin is used as a carbon precursor and Pluronic copolymer P123 is used as a template and 2,5‐dimercapto‐1,3,4‐thiadiazole is used as sulfur source. Prepared S‐doped MMC processes a high specific surface area, the Fe₃O₄ particles are well embedded in the mesoporous carbon walls that exhibit a strong magnetic response, and the hydrated iron nitrate loading amount of 0.808 g is the best. Batch adsorption experiments are carried out at different pH, initial concentration, temperature, and contact time on the adsorption of methyl orange (MO) by S‐doped MMC. The kinetic data of the adsorption process are better fitted with pseudo‐second‐order model than the pseudo‐first‐order model. Langmuir model is more suitable for the equilibrium data than Freundlich model. The thermodynamic parameters including ΔG⁰, ΔH⁰, and ΔS⁰ indicate that the adsorption is a feasible, spontaneous, and endothermic process. Finally, it is found that the coexistence of PO₄^3?, NO₃^?, SO₄^2?, Cl^?, and CO₃^2? does not influence the adsorption process. These results illustrate S‐doped MMC can be an efficient adsorbent for the removal of MO from wastewater.  相似文献   

HPLC separation of higher fullerenes in the synthetical “graphite smokes” soot     

Jun Zhang  Luann Becker  Handong Liang  Yang Luo  Wei Xu  Hongcui Wang 《中国地球化学学报》2012,31(3):303-308

Higher fullerenes(C84,C90,C92,C94 and C96) were successfully isolated from the Soxhlet extract of the synthetical "Graphote Smokes" soot(GS sample) by using a big Cosmosil Buckysep(Phenomenex) column(250 mm × 10 mm) with a large injection.The fractions isolated have been determined by high performance liquid chro-matography(HPLC) and laser desorption mass spectrometry(LDMS).It is found that there are different fullerenes molecules in different fractions with retention time.The result indicates that fullerenes do exist in GS samples.Also,it excludes the suspicion to some extent that fullerene molecules might be generated by the laser desorption process in the LDMS.In addition,it also provides the experimental basis for the study of natural higher fullerenes and might be helpful to figure out the question if higher fullerenes do exist in the natural samples.  相似文献   

Highly Efficient,Ultra‐Low Energy Consumption Process for Phenol Wastewater Treatment with Ultra‐Low Carbon Emission     

Yalei Zhang  Deyi Li  Yonggang Zhang  Xuefei Zhou  Jie Hong  Ming Jiang 《洁净——土壤、空气、水》2013,41(9):865-871

Phenol is one of the main pollutants in phenol wastewater and has been proved non‐biodegradable. In this study, based on strongly ring‐opening capability of boron doped diamond film electrode, a highly efficient and energy‐saving method with ultra‐low carbon emission is established through a combination of electrochemical oxidation and biological degradation. On one hand, electrochemical oxidation as pretreatment can solve the critical problem that phenol wastewater is a biological recalcitrant. On the other hand, the relatively low current efficiency during the late stage of electrochemical oxidation can be solved by follow‐up biological treatment, thus reduce the energy consumption and the cost significantly. More importantly, the carboxylic acids (oxidized from phenol) can be fully used as carbon source (no additional carbon source is added) for microbial growth instead of being oxidized to carbon dioxide and water through selecting optimizing sequencing batch reactor access time, so the carbon emission is greatly reduced. The results showed that it can save about 76.5% energy consumption and about 51.2% chemical oxygen demand can be used to maintain microorganism self‐reproduction. This is significant that this combined technology not only runs highly effectively at low cost, but also reduces the emission of greenhouse gas, carbon dioxide, thus environment friendly with wide application prospects.  相似文献   

影响芜湖葡萄商品果率关键气候因子特征及预测     

司红君  付伟  马菊  程传云 《气象科技》2017,45(1):195-202

基于1994—2014年研究区葡萄的逐年商品果率数据,1965—2014年芜湖市逐月的气象数据和1981年7月至2014年6月国家气候中心的逐月88项新大气环流指数、26项海温指数,使用相关性分析、线性趋势、MannKendall和多元逐步回归分析,对影响葡萄商品果率的关键气候因子进行遴选,并在此基础上对遴选因子的近50年变化特征和短期气候预测进行了分析与研究。结果表明:影响葡萄商品果率的关键气候因子有7、8月的平均气温(T_7,T_8)、最高气温(T_(max7),T_(max8))、最低气温(T_(min7),T_(min8))、相对湿度(R_(H7),R_(H8))、日照时数(S_7,S_8),以及8月的平均气温日较差(ΔT_8),近50年T7、T_(max7)和T_(min7)显著升高,RH7、ΔT8和S8显著下降,其中T7、T_(max7)、ΔT_8的变化以渐变为主,而T_(min7)、R_(H7)、ΔT_8则发生过突变。这些关键气候因子与前期1年内的多项大气环流指数和海温指数显著相关,并遴选其中关键指数作为预测芜湖市7、8月葡萄商品果率关键气候因子的短期气候预测指标,计算出气候因子的预测方程,以期为葡萄种植能够有效应对气候影响、保证商品果率提供帮助。  相似文献   

北黄海盆地LV井侏罗系烃源岩特征及油源对比     

赵青芳  李双林  温珍河  龚建明  肖国林  吴亮亮 《沉积学报》2016,34(4):794-802

对北黄海盆地LV井中、上侏罗统烃源岩及上侏罗统原油（油砂抽提物）进行常规有机地球化学分析和碳同位素测试,分析研究烃源岩和原油的地球化学特征并探讨原油的来源问题。测试结果显示,侏罗系烃源岩达成熟-高熟阶段,有机质类型以Ⅲ型为主。中侏罗统烃源岩有机碳含量较高,但生烃潜能、氯仿沥青“A”及总烃含量低值,属于差的烃源岩。干酪根碳同位素总体偏重（-24.4‰～-23.5‰）,与原油碳同位素特征（-29‰左右）差异显著,排除与原油的母岩关系。上侏罗统烃源岩有机碳含量较中侏罗统低,但生烃潜能、氯仿沥青“A”及总烃含量高值。上侏罗统烃源岩抽提氯仿沥青“A”碳同位素（-26‰～-21.5‰）特征、单体烃碳同位素分布模式及甾萜烷生物标志物特征都与原油相似,综合分析认为原油应该来源于上侏罗统中干酪根类型较好、母质为混源的成熟烃源岩。  相似文献