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991.
利用部分改进了的中尺度模式MM5V3对2006年2月7~8日甘肃北部地区一次冷云降雪过程进行了人工催化的数值试验,研究加入人工冰晶对祁连山北坡地区冷性层云降雪的影响.进行了不同剂量和不同高度的催化试验,详细分析了催化后的微物理过程和动力热力过程的变化.结果表明:累积降雪中心的上风方含有过冷云水的区域为催化潜力区.催化后累积降雪中心雪量增加,增雪区周围出现分散的减雪区.过冷云水最多并且最缺乏冰晶粒子的层次具有很好的催化条件.加人人工冰晶后消耗了水汽和过冷云水,冰晶和雪的量值均有所增加,雪碰并冰晶过程、冰品转化过程、凝华过程是雪增长的主要过程,相态变化引起的潜热增加导致升温和上升运动加强.这种变化同时使周围的垂直运动和水成物含量发生改变,周围的上升运动减弱,雪的含量减少,产生了减雪区. 相似文献
992.
Anthropogenic Direct Radiative Forcing of Tropospheric Ozone and Aerosols from 1850 to 2000 Estimated with IPCC AR5 Emissions Inventories 下载免费PDF全文
This study estimates direct radiative forcing by tropospheric ozone and all aerosols between the years 1850 and 2000, using the new IPCC AR5 (the Intergovernmental Panel on Climate Change Fifth Assessment Report) emissions inventories and a fully coupled chemistry-aerosol general circulation model. As compared to the previous Global Emissions Inventory Activity (GEIA) data, that have been commonly used for forcing estimates since 1990, the IPCC AR5 emissions inventories report lower anthropogenic emissions of organic carbon and black carbon aerosols and higher sulfur and NOx emissions. The simulated global and annual mean burdens of sulfate, nitrate, black carbon (BC), primary organic aerosol (POA), secondary organic aerosol (SOA), and ozone were 0.79, 0.35, 0.05, 0.49, 0.34, and 269 Tg, respectively, in the year 1850, and 1.90, 0.90, 0.11, 0.71, 0.32, and 377 Tg, respectively, in the year 2000. The estimated annual mean top of the atmosphere (TOA) direct radiative forcing of all anthropogenic aerosols based on the AR5 emissions inventories is -0.60 W m^-2 on a global mean basis from 1850 to 2000. However, this is -2.40 W m-2 when forcing values are averaged over eastern China (18-45°N and 95-125°E). The value for tropospheric ozone is 0.17 W m^-1 on a global mean basis and 0.24 W m^-2 over eastern China. Forcing values indicate that the climatic effect of aerosols over eastern China is much more significant than the globally averaged effect. 相似文献
993.
994.
为了认清鄂尔多斯盆地志丹探区西南部三叠系延长组长4+5段有利储层的分布规律,通过大量岩石薄片和铸体薄片的镜下鉴定,并结合扫描电镜、阴极发光和X-衍射等测试结果,研究了该区长4+5段主要成岩作用及其对储层物性的影响.研究结果显示,长4+5段主要成岩作用类型有压实作用、胶结作用和溶蚀作用:强烈的压实作用及胶结作用导致其原生孔隙丧失殆尽,成为形成特低孔渗储层的主要原因,而晚期较弱的溶蚀作用,对储层的改善发挥了较大作用,从而使鄂尔多斯盆地延长组发育部分有利储层,形成较好的储集-成岩相带. 相似文献
995.
Haili Long Rudy Swennen Anneleen Foubert Manuel Dierick Patric Jacobs 《Sedimentary Geology》2009,220(1-2):116-125
Microfocus X-ray computed tomography (µCT) measurements were performed on deltaic sandstone samples from the diagenetically altered Westphalian C strata (Campine basin, north-east Belgium) in order to collect three dimensional data on mineral (quartz, kaolinite, ankerite, etc.) and porosity distribution. The acquired µCT data were compared with point counting results of stained impregnated thin-sections to qualify the sensitivity of µCT. Comparison between techniques shows positive results with regard to the quantification of main mineral phases such as quartz and ankerite, and porosity distribution. However, major discrepancies exist when studying the clay minerals. This can be explained by the influence of microporosity associated with these clay minerals, resulting in partial volume effects. 相似文献
996.
新显色剂5-(5-氟-2-吡啶偶氮)-2,4-二氨基甲苯的合成及其与钯的显色反应 总被引:1,自引:0,他引:1
合成并用红外光谱和元素分析鉴定了氟代吡啶偶氮氨类新试剂5-(5-氟-2-吡啶偶氮)-2,4-二氨基甲苯(5-F-PADAT),并研究了该试剂与钯显色的反应。结果表明,在0.32~3.84 mol/L高氯酸溶液中,试剂与钯形成1∶1的紫红色络合物,其最大吸收峰位于566 nm,表观摩尔吸光系数为4.84×104L.mol-1.cm-1,钯的浓度在0~2000μg/L符合比耳定律。方法选择性好,大量常见金属离子不干扰钯的测定,操作简单,应用于矿样和催化剂中微量钯的测定,结果与原子吸收光谱法相符。 相似文献
997.
B.B. Singh V.R. Chitnis D. Bose M.A. Rahman S.S. Upadhya K.S. Gothe B.K. Nagesh P.N. Purohit Shobha K. Rao Kamesh K. Rao S.K. Sharma P.V. Sudersan B.L. Venkateshmurthy P.R. Vishwanath B.S. Acharya 《Astroparticle Physics》2009,32(2):120-128
We present the results of observation of the Geminga pulsar carried out in the TeV energy band during the 6 year period spanning 2000–2006 using the Pachmarhi Array of Cherenkov Telescopes (PACT). A long stretch of data, new computer codes and the “Tempo” package have been used in the present analysis. We have searched for evidence of pulsed emission of γ-rays from the Geminga pulsar using the post-glitch pulsar elements obtained by Jackson and Halpern from X-ray/γ-ray satellite data. We do not see any significant evidence for pulsed emission from the Geminga pulsar at a threshold energy of 825 GeV. In this paper we present our results on the light curve in the TeV energy band, set an upper limit on the time averaged flux of γ-rays, and compare our results with other ground based observations. 相似文献
998.
M.J. Hwang Y.J. Kwon H.J. Kim J.W. Kwak S.C. Kim S.K. Kim T.Y. Kim S.Y. Kim H.S. Lee M.J. Lee S.S. Myung Y.D. Kim J.I. Lee W.G. Kang I.S. Hahn M.H. Lee KIMS Collaboration 《Astroparticle Physics》2009,31(6):412-416
A search for the neutrinoless double-beta decay of 124Sn was carried out using the tin-loaded liquid scintillator for an active source-detector technique. Tin (32.6%) in weight was successfully loaded into the liquid scintillator, and light output was as high as 57% of the unloaded liquid scintillator. A tin-loaded liquid scintillator with 1.1 ℓ volume was installed at the 700 m underground laboratory in YangYang, and data were taken for 5285 h. No evidence for the 0νββ decay was found and a lower limit on the 124Sn half-life was obtained to be 2.0×1019 year with 90% C.L. The new limit represents a significant improvement with respect to those previously available for 124Sn. 相似文献
999.
In this paper we show the existence of three new families of planar central configurations for the 5-body problem with the
following properties: three bodies are on the vertices of an equilateral triangle and the other two bodies are on a perpendicular
bisector. 相似文献
1000.
Bilis (0604) is a strong tropical storm that sustained over land for a long time, bringing torrential rain. With conventional observation data, radar data and infrared satellite imagery, Mesoscale Convective Systems (MCSs) are found to form and develop successively, which cause torrential rain. Then numerical simulation is conducted using MM5 to simulate a 66-h post-landfall process. The simulated distribution and intensity of precipitation match the observation well. With the simulated result, the characteristics and process of MCS development are analyzed with the finding that the convergence of the tropical depression and South China Sea (SCS) summer monsoon over The south of China causes the formation of a mesoscale vortex, mesoscale convergence center and mesoscale convergence line, which are favorable to the development and sustaining of the MCSs. A sensitivity experiment indicates that the SCS summer monsoon transports unstable energy and water vapor continuously, which is of vital importance to rainstorms. 相似文献