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991.
The effects of ferrous ions on cathodic and anodic polarization behavior of the X60 steel in CO2 saturated salty water were studied by potentio-dynamic polarization method. The results show that the reducing current peak
of cathodic polarization is affected significantly if FeCl2 is added to the salty solution of controlled pH, but not the anodic polarization. It is considered that the ferrous ions
accelerate the formation of a protective ferrous carbonate film. Films formed by addition of ferrous ions and those formed
by ferrous ions produced from steel corrosion have the same forming mechanism. The former can fully meet the formative condition
of the film and can play the role of inhibitor. 相似文献
992.
本文采用流域内气象站资料,以正交函数展开方法,分析了流域气候背景场的基本结构及共季节变化特征,并根据1985—1988年间在流域内若干河段的小气候考察资料,探讨河流对局地小气候要素的影响。本文给出的河陆风环流平衡气球探测结果,表明了河陆风环流结构的某些特征。 相似文献
993.
Wu Chaoyuan Li Jiajun Xia Enzhan Peng Zhuosheng Tan Shuzhi Li Jun Wen Zongcun Huang Xiaohang Cai Zulin Chen Guojun 《中国海洋湖沼学报》1989,7(4):327-334
A 2-year study onKappaphycus alvarezii (Doty) Doty introduced to Hainan Island from the Philippines in 1985 showed promising results. The average daily growth in
weight reached 10% at a favourable temperature of about 26°C. Experimental results showed that timely cutting of the plant
was an effective way to obtain new cuttings for cultivation and accelerate growth. New cuttings 0.05 kg in weight are suggested
to be used as “seeds” and the old plant should be harvested. At present, artificial cultivation with a type of underwater
raft applicable in places where there is strong wind will expand cultivation to more regions in Hainan Province.
This paper was originally published in Chinese inOceanologia et Limnologia Sinica
19(5): 410–418, 1988. The plant under discussion wasEucheuma alvarezii Doty which was previously calledE. striatum in the article, and which now becomesKappaphycus alvarezii (Doty) Doty. To the original title, “in China” was added. Only the essence of the original article was presented. 相似文献
994.
本文首先介绍了热力学自由能上限的普遍公式及其推导思想,然后应用于非热电子束的具体形式,从而估计太阳射电活动中的毫秒级尖峰辐射的“饱和”能量;在此基础上,进一步为饱和时间问题作一般性的讨论;最后,在把尖峰“饱和”的几种机制进行了比较之后提出:由于尖峰能量远未达到非线性饱和的水平,因此,由某种外部因素(例如加速机制等)所导致的高能电子束的非均匀性可能是一种较为合理的模型。 相似文献
995.
996.
本文首先利用传播矩阵法构造出了水平分层弹性介质在表载、体力及内部力源联合作用下的一般模型。然后利用“对应原理”将弹性问题的一般模型推广到粘弹性问题的一般模型——粘弹性分层介质传播矩阵基本方程。最后用粘弹性分层介质传播矩阵方程对一个实际地学问题做了试算,计算结果说明,用传播矩阵法处理粘弹性问题是非常有效的。 相似文献
997.
Y.?A.?LiouEmail author A.?G.?Pavelyev J.?Wickert C.?Y.?Huang S.?K.?Yan S.?F.?Liu 《GPS Solutions》2004,8(2):103-111
We show that the amplitude of the Global Positioning System (GPS) signals in the radio occultation (RO) experiments is an indicator of the activity of the gravity waves (GW) in the atmosphere. The amplitude of the GPS RO signals is more sensitive to the atmospheric wave structures than is the phase. Early investigations used only the phase of the GPS occultation signals for statistical investigation of the GW activity in the height interval 10–40 km on a global scale. In this study, we use the polarization equations and Hilbert transform to find the 1-D GW radio image in the atmosphere by analyzing the amplitude of the RO signal. The radio image, also called the GW portrait, consists of the phase and amplitude of the GW as functions of height. We demonstrate the potential of this method using the amplitude data from GPS/Meteorology (GPS/MET) and satellite mission Challenge Mini-satellite Payload (CHAMP) RO events. The GW activity is nonuniformly distributed with the main contribution associated with the tropopause and the secondary maximums related to the GW breaking regions. Using our method we find the vertical profiles of the horizontal wind perturbations and its vertical gradient associated with the GW influence. The estimated values of the horizontal wind perturbations are in fairly good agreement with radiosonde data. The horizontal wind perturbations v(h) are ±1 to ±5 m s with vertical gradients dv/dh ±0.5 to ±15 m s km at height 10–40 km. The height dependence of the GW vertical wavelength was inferred through the differentiation of the GW phase. Analysis of this dependence using the dispersion relationship for the GW gives the estimation of the projection of the horizontal background wind velocity on the direction of the GW propagation. For the event considered, the magnitude of this projection changes between 1.5 and 10 m s at heights of 10–40 km. We conclude that the amplitude of the GPS occultation signals contain important information about the wave processes in the atmosphere on a global scale. 相似文献
998.
Urban heat island effect on annual mean temperature during the last 50 years in China 总被引:11,自引:0,他引:11
Summary Based on Chinas fifth population survey (2000) data and homogenized annual mean surface air temperature data, the urban heat island (UHI) effect on the warming during the last 50 years in China was analyzed in this study. In most cities with population over 104, where there are national reference stations and principal stations, most of the temperature series are inevitably affected by the UHI effect. To detect the UHI effect, the annual mean surface air temperature (SAT) time series were firstly classified into 5 subregions by using Rotated Principal Components Analysis (RPCA) according to its high and low frequency climatic change features. Then the average UHI effect on each subregions regional annual mean STA was studied. Results indicate that the UHI effect on the annual mean temperatures includes three aspects: increase of the average values, decrease of variances and change of the climatic trends. The effect on the climatic trends is different from region to region. In the Yangtze River Valley and South China, the UHI effect enhances the warming trends by about 0.011°C/decade. In the other areas, such as Northeast, North-China, and Northwest, UHI has little impact on the warming trends of the regional annual temperature; while in the Southwest of China, introducing UHI stations slows down the warming trend by –0.006°C/decade. But no matter what subregion it is, the total warming/cooling of these effects is much smaller than the background change in regional temperature. The average UHI effect for the entire country, during the last 50 years is less than 0.06°C, which agrees well with the IPCC (2001). This suggests that we cannot conclude that urbanization during the last 50 years has had much obvious effect on the observed warming in China. 相似文献
999.
Geospatial-temporal analysis of land-use changes in the Yellow River Delta during the last 40 years 总被引:5,自引:0,他引:5
Qinghua?YeEmail author Gaohuan?Liu Guoliang?Tian Shenliang?Chen Chong?Huang Shupeng?Chen Qingshen?Liu Jun?Chang Yanan?Shi 《中国科学D辑(英文版)》2004,47(11):1008-1024
Research on land use/land cover changes (LUCC)has been the core project of the Global EnvironmentalChanges since the 1990s[1—6]. Scientists at home andabroad have been laying emphasis on integrationstudies on land-use change by “space and process”features[7—10] as researches on LUCC are in a greatdeal. It is of paramount important for us to studyLUCC at various spatial-temporal scales and build aquantitative assessment of land-use conversion by in-tegrated spatial-temporal features. … 相似文献
1000.
Environmental records of lacustrine sediments in different time scales: Sediment grain size as an example 总被引:2,自引:0,他引:2
CHEN Jing’an WAN Guojiang David Dian Zhang ZHANG Feng & HUANG Ronggui . State Key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang China . Department of Geography Geology University of Hong Kong Pokfulam Road Hong Kong China 《中国科学D辑(英文版)》2004,47(10):954-960
Understanding the past is the key to know thepresent and to predict the future. As a core project ofthe International Geosphere Biosphere Program, PastGlobal Changes (PAGES) aims to reconstruct theevolution history of global climate, global environ-ment and global ecosystem with resort to all kinds ofnatural records, so as to reveal the change rules(change processes, change amplitude and change rate)of the global environment and thus provide scientificbasis for predicting climate changes p… 相似文献