共查询到20条相似文献，搜索用时 163 毫秒
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对地面最高温度和最高气温观测方法对比以及实际观测数据进行分析,解释造成自动站与人工对比观测地面最高温度常出现较大误差的根本原因,得出合理结论,并从安装方法进行改进,研究新的观测方法,从而减小日照影响因素,实现误差的减小,进一步提高观测数据准确度。结果表明,自动站铂电阻温度计和水银温度表材质及表面光滑程度的不同,导致对日照的反照率和吸收率不同,从而引起自动站和人工观测产生较大误差。铂电阻温度计受太阳辐射影响严重。利用＂百叶箱＂方法,可以有效地消除仪器受日照影响,获得更准确的观测数据。解决的方案是：模拟最高气温观测方法,通过模拟百叶箱效果,屏蔽太阳辐射,在不影响铂电阻温度计和水银温度表感应部分周围土壤正常吸收太阳辐射的情况下,使2种采集仪器避免太阳辐射影响,正常感应地面温度;或在温度计和温度表感热部分盖上一层薄的观测场土壤,即可使采集器和地表获得更相近的反照率和更接近地表的吸热特性,从而获得更精确的观测值,提高观测质量。 相似文献
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日光温室土质墙体内温度与室内气温的测定分析 总被引：9，自引：0，他引：9
为研究日光温室土质墙体的保温性及室内温度环境特征,对日光温室的后墙、地面、空气进行了不同层次的温度监测和理论分析.结果表明:日光温室后墙在传热过程中,由内向外随墙体厚度的增大传入热量逐渐减少.在后墙垂直方向内表层0.2 m处,墙体中下部温度最高,顶部和基部温度较低;3月份一日内墙体表面温度平均比地表面温度高3.3℃;夜间放热时间比地面长约3 h,且单位面积墙体比单位面积地面放热多.白天,在温室南北方向由北向南气温逐渐增高;垂直方向气温由下到上逐渐升高;夜间,在南北方向由北向南气温逐渐降低,垂直方向气温没有明显变化.无论白天夜间,日光温室内南北方向气温差异比垂直方向气温差异大. 相似文献
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[目的]研究基于MODIS的黄河中游地表反照率时空变化。[方法]利用2001～2010年MODIS地表反照率产品(MCD43B3)以及气象站降水和气温数据,采用简单相关分析和偏相关分析方法,研究了黄河中游地区地表反照率时空分布特征及其与降水、气温的相关关系。[结果]研究区地表反照率年内年际波动变化,不同地表覆盖类型地表反照率年平均值大小顺序为耕地建设用地草地林地。不同地形、地表覆盖类型地表反照率与降水和气温的相关关系不同。[结论]该研究为中长期气候预报水平的提高提供理论依据。 相似文献
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以内蒙古赤通高速公路一处进行植被恢复的工程创面为研究对象,在植被恢复的不同时期,利用红外成像测温仪,多次进行表面温度的实地观测;在观测基础上分析了植被恢复在路域小气候中的温度效应。结果表明:对于半干旱地区的工程创面,在南坡(阳坡)使用浆砌片石护坡,会产生比裸露的自然岩石还要高的表面温度,从而加剧夏天公路路域范围的高温;而在南坡恢复植被覆盖可以显著地降低边坡表面温度,有利于局地小气候的改善,可使夏、秋、冬季南北坡之间的表面温度差下降5～10℃,改善两坡热量的不均程度。土壤水分条件对这种改善效果有明显的影响。 相似文献
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温度变化对酚醛胶在竹材表面动态润湿性的影响 总被引：1，自引：0，他引：1
为了探讨温度变化对酚醛胶在竹材表面润湿性的影响,该文采用测量动态接触角方法,用润湿模型分析了酚醛胶在20、60、80和100℃环境下,对层积材用竹片青、黄表面的润湿性和铺张渗透系数k值的影响. 结果表明:酚醛胶在竹青和竹黄表面的润湿性差异不显著;随着温度的升高,接触角(起始和平衡接触角)增大,k值减小,竹材表面的润湿性、铺张和渗透性变差;但温度变化对竹青和竹黄表面k值影响的规律不同;随着温度的升高,竹材表面的酚醛胶会出现收缩、干瘪现象,温度越高,出现干瘪、收缩时间越短. 相似文献
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Electrical heat sources implanted in the abdominal cavities of sheep were heated to give initial temperatures of 42 degrees and 45 degrees C at the surfaces of the heaters. During 18 days of constant heating, a vascularized connective-tissue envelope encapsulated the heat sources, and the temperatures at the surfaces of the heaters declined 0.8 degrees and 1.8 degrees C, respectively. The degree of vascularization and the magnitude of the decrease in the surface temperature appeared to be related to the proximity of the tissue's initial temperature to 45 degrees C, a temperature ordinarily considered detrimental to cell structure. The vascularization thus appears to be adaptive. 相似文献
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Inelastic electron tunneling spectroscopy at low temperatures was used to investigate vibrations of Au(111) and Cu(111). The low-energy peaks at 9 millielectron volts (meV) on Au(111) and 21 meV on Cu(111) are attributed to phonons at surfaces. On Au(111), the phonon energy is not influenced by the different stacking of the surface atoms, but it is considerably influenced by different atomic distances within the surface layer. The spatial variation of the phonon excitation is measured in inelastic electron tunneling maps on Au(111), which display atomic resolution. This atomic resolution is explained in terms of site-specific phonon excitation probabilities. 相似文献
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A model of the desorption and adsorption of a polymer layer at a planar surface indicates a transition from exponential kinetics at high temperatures to nonexponential kinetics (stretched exponential with index one-half) at lower temperatures where these processes are diffusion-limited. Measurements of polystyrene desorption through polyisoprene overlayers show this predicted transition. Corroborative results are obtained for polystyrene desorption through polymethylmethacrylate overlayers. This identification of two distinct kinetic regimes suggests a unifying perspective from which to analyze polymer and biopolymer mobility at surfaces. 相似文献
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Appreciable natural thermoluminescence with glow curve peaks at about 350 degrees centigrade for lunar fines and breccias and above 400 degrees centigrade for crystalline rocks has been recognized in lunar samples. Plagioclase has been identified as the principal carrier of thermoluminescence, and the diference in peak temperatures indicates compositional or structural differences between the feldspars of the different rock types. The present thermoluminescence in the lunar samples is probably the result of a dynamic equilibrium between acquisition from radiation and loss in the lunar thermal environment. A progressive change in the glow curves of core samples with depth below the surface suggests the use of thermoluminescence disequilibrium to detect surfaces buried by recent surface activity, and it also indicates that the lunar diurnal temperature variation penetrates to at least 10.5 centimeters. 相似文献
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Device-quality copper and nickel films were deposited onto planar and etched silicon substrates by the reduction of soluble organometallic compounds with hydrogen in a supercritical carbon dioxide solution. Exceptional step coverage on complex surfaces and complete filling of high-aspect-ratio features of less than 100 nanometers width were achieved. Nickel was deposited at 60 degrees C by the reduction of bis(cyclopentadienyl)nickel and copper was deposited from either copper(I) or copper(II) compounds onto the native oxide of silicon or metal nitrides with seed layers at temperatures up to 200 degrees C and directly on each surface at temperatures above 250 degrees C. The latter approach provides a single-step means for achieving high-aspect-ratio feature fill necessary for copper interconnect structures in future generations of integrated circuits. 相似文献
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不同杀菌剂对富贵竹修口和顶侧芽生长的初步研究 总被引：7，自引：1，他引：7
刘付东标 《西南大学学报(自然科学版)》2001,23(4):374-377
以12个月生富贵竹剥除叶片的茎干剪取做富贵竹塔的外层（10cm）和次外层（15cm）的枝条为材料,采用不同杀菌剂分别对其下发口和上切口进行处理,比较不同杀菌剂对其枝条上切口修口和顶侧芽生长的影响。试验结果表明,下切口1种和2种混合杀菌剂处理,对参试材料的上切口白色枝数、平滑枝数、顶侧芽长度,其差异均不显著;上切口3种杀菌处理,对参试材料的上切口白色枝数、平滑枝数和顶测芽长度差异均达极显著水平;15cm枝条各处理组合的上切口白色枝数差异达极显著水平。参试材料的上切口平滑枝数（X）与顶侧芽长度（Y）均呈极显著相关关系。 相似文献
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Recent radar observations of Mercury have revealed the presence of anomalous radar reflectivity and polarization features near its north and south poles. Thermal model calculations show that, despite Mercury's proximity to the sun, the temperatures of flat, low-reflectivity surfaces at Mercury's poles are not expected to exceed 167 kelvin. The locations of the anomalous polar radar features appear to be correlated with the locations of large, high-latitude impact craters. Maximum surface temperatures in the permanently shadowed regions of these craters are expected to be significantly colder, as low as 60 kelvin in the largest craters. These results are consistent with the presence of water ice, because at temperatures lower than 112 kelvin, water ice should be stable to evaporation over time scales of billions of years. 相似文献
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The electronic and geometric structures of surfaces are closely related to each other. Conventional surface science techniques can study one or the other, but not both at the same time. Recent developments in scanning tunneling microscopy have made it possible to study simultaneously the electronic and geometric structure of Si(111) and Si(001) surfaces. Surface states can be atomically resolved in space and energy; thus the electronic structure of single atoms on surfaces can be studied in detail. The various surface states observed on silicon surfaces are found to derive from different atomic-scale features in the surface geometric structure. Scanning tunneling microscopy has now bridged the gap between electronic and geometric structure, providing a unique opportunity to obtain a better understanding of many surface processes at the atomic level. 相似文献