In July of 1987, the Sampling Survey of Children's Situation was conducted in 9 provincesautonomous regions of China. A stratified two--stage cluster sampling plan was designed for thesurvey. The paper presents th...In July of 1987, the Sampling Survey of Children's Situation was conducted in 9 provincesautonomous regions of China. A stratified two--stage cluster sampling plan was designed for thesurvey. The paper presents the methods of stratification, selecting n=2 PSU's (cities/counties) withunequal probabilities without replacement in each stratum and selecting residents/village committeein each sampled city/county. All formulae of estimating population characteristics (especiallypopulation totals and the ratios of two totals), and estimating variances of those estimators aregiven. Finally, we analyse the precision of the survey preliminarily from the result of dataprocessing.展开更多
The metamorphosed sedimentary type of iron deposits（BIF） is the most important type of iron deposits in the world, and super-large iron ore clusters of this type include the Quadrilatero Ferrifero district and Caraj...The metamorphosed sedimentary type of iron deposits（BIF） is the most important type of iron deposits in the world, and super-large iron ore clusters of this type include the Quadrilatero Ferrifero district and Carajas in Brazil, Hamersley in Australia, Kursk in Russia, Central Province of India and Anshan-Benxi in China. Subordinated types of iron deposits are magmatic, volcanic-hosted and sedimentary ones. This paper briefly introduces the geological characteristics of major super-large iron ore clusters in the world. The proven reserves of iron ores in China are relatively abundant, but they are mainly low-grade ores. Moreover, a considerate part of iron ores are difficult to utilize for their difficult ore dressing, deep burial or other reasons. Iron ore deposits are relatively concentrated in 11 metallogenic provinces（belts）, such as the Anshan-Benxi, eastern Hebei, Xichang-Central Yunnan Province and middle-lower reaches of Yangtze River. The main minerogenetic epoches vary widely from the Archean to Quaternary, and are mainly the Late Archean to Middle Proterozoic, Variscan, and Yanshanian periods. The main 7 genetic types of iron deposits in China are metamorphosed sedimentary type（BIF）, magmatic type, volcanic-hosted type, skarn type, hydrothermal type, sedimentary type and weathered leaching type. The iron-rich ores occur predominantly in the skarn and marine volcanic-hosted iron deposits, locally in the metamorphosed sedimentary type（BIF） as hydrothermal reformation products. The theory of minerogenetic series of mineral deposits and minerogenic models has applied in investigation and prospecting of iron ore deposits. A combination of deep analyses of aeromagnetic anomalies and geomagnetic anomalies, with gravity anomalies are an effective method to seeking large and deep-buried iron deposits. China has a relatively great oresearching potential of iron ores, especially for metamorphosed sedimentary, skarn, and marine volcanic-hosted iron deposits. For the lower guarantee degree of iron and steel industry, China should give a trading and open the foreign mining markets.展开更多
1.IntroductionHigh-purity elements are the basic materials in electronics,communication,aerospace,atomicenergy and semiconductor material industries.Its development is a decisive factor for high-tech in-dustries.The h...1.IntroductionHigh-purity elements are the basic materials in electronics,communication,aerospace,atomicenergy and semiconductor material industries.Its development is a decisive factor for high-tech in-dustries.The high-purification of non-ferrous metals is of great significance.It conduces to determining展开更多
It is of great significance with the development of China’s foreign trade and the economic and trade expansion in China by foreign businessmen to get a clear understanding of the present economic situation and the 19...It is of great significance with the development of China’s foreign trade and the economic and trade expansion in China by foreign businessmen to get a clear understanding of the present economic situation and the 1997 economic trends in China.展开更多
1.Rare Earth Resources in China1.1.Reserves and distributionChina is the country which is the richest in the world in rare earth(RE)resources of allavailable varieties of minerals and their deposits are located in vas...1.Rare Earth Resources in China1.1.Reserves and distributionChina is the country which is the richest in the world in rare earth(RE)resources of allavailable varieties of minerals and their deposits are located in vast areas in China.Reserveshave been estimated at a grand total of 36 million ton,which is 80% of the world(RE)de-posits.The majority of these deposits are concentratedly located in Baiyunebo mine of the展开更多
The state of welders training in China is introduced in this paper.There are different specifications because of variable examining organizations,as the deeping of reform and openning in China, welders are trained acc...The state of welders training in China is introduced in this paper.There are different specifications because of variable examining organizations,as the deeping of reform and openning in China, welders are trained according to variable specification to fit specific requirement.展开更多
1. The Power Industry and Cogeneration in China 1.1 The Power Industry in China The power industry has developed rapidly in China in recent decades. In 1994, total electricity generation was 927.8 TWh and the total in...1. The Power Industry and Cogeneration in China 1.1 The Power Industry in China The power industry has developed rapidly in China in recent decades. In 1994, total electricity generation was 927.8 TWh and the total installed capacity was 199.80 GW. It is broken down as follows: hydropower 49.0 GW. 24.5 %; thermal power 148.73 GW, 74.4c/c: and nuclear power 2.1 GW, 0.7%.展开更多
With the rapid development of national economy in China, pumped-storage power plant(PSPP) has developed very fast for its special stable and dynamic benefits in recent years.Because of the ever-increasing power load a...With the rapid development of national economy in China, pumped-storage power plant(PSPP) has developed very fast for its special stable and dynamic benefits in recent years.Because of the ever-increasing power load and its peak-to-valley ratio, customers have higherexpectation for the securityand quality ofpower supply. PSPPs are playing a role in load regulation,energy saving and reliable operation of power girds with its unique peak-shifting character.展开更多
Hydropower resources in river basins are typically developed in a cascade manner. The cascade hydropower stations use water from the same river; in a sense, they form a cluster of hydropower stations which are linked ...Hydropower resources in river basins are typically developed in a cascade manner. The cascade hydropower stations use water from the same river; in a sense, they form a cluster of hydropower stations which are linked together by the river stream. The dispatch and management of the cascade hydropower stations in a river basin differ from those of an ordinary single hydropower station. Without doubt, unified dispatch can facilitate the full harnessing of hydraulic resources and is in a better position to fulfill the objectives in the development of river basin. As a result, more and more river-basin cascade power stations around the world implement unif ied dispatching.展开更多
THE BASIC SITUATION The Chinese govemment has always been devoting a great deal of attention to the research of diarrhoea prevention and control. Early in 1950’s we wiped out the classical cholera which had been epid...THE BASIC SITUATION The Chinese govemment has always been devoting a great deal of attention to the research of diarrhoea prevention and control. Early in 1950’s we wiped out the classical cholera which had been epidemic over a century in old China, brought typhoid fever and dysentry under control by preventing them from spreading in large areas, and reduced to different extents the incidence and mortality of other types of diarrhoea. Since China is a country with a vast territory and a large population, and is greatly varied展开更多
基金Supported partially by the National Funds of Natural Sciences, 7860013
文摘In July of 1987, the Sampling Survey of Children's Situation was conducted in 9 provincesautonomous regions of China. A stratified two--stage cluster sampling plan was designed for thesurvey. The paper presents the methods of stratification, selecting n=2 PSU's (cities/counties) withunequal probabilities without replacement in each stratum and selecting residents/village committeein each sampled city/county. All formulae of estimating population characteristics (especiallypopulation totals and the ratios of two totals), and estimating variances of those estimators aregiven. Finally, we analyse the precision of the survey preliminarily from the result of dataprocessing.
基金supported by the National Natural Science Foundation of China (grant No. 40773038the Program of High-level Geological Talents (201309)Youth Geological Talents (201112) of the China Geological Survey
文摘The metamorphosed sedimentary type of iron deposits（BIF） is the most important type of iron deposits in the world, and super-large iron ore clusters of this type include the Quadrilatero Ferrifero district and Carajas in Brazil, Hamersley in Australia, Kursk in Russia, Central Province of India and Anshan-Benxi in China. Subordinated types of iron deposits are magmatic, volcanic-hosted and sedimentary ones. This paper briefly introduces the geological characteristics of major super-large iron ore clusters in the world. The proven reserves of iron ores in China are relatively abundant, but they are mainly low-grade ores. Moreover, a considerate part of iron ores are difficult to utilize for their difficult ore dressing, deep burial or other reasons. Iron ore deposits are relatively concentrated in 11 metallogenic provinces（belts）, such as the Anshan-Benxi, eastern Hebei, Xichang-Central Yunnan Province and middle-lower reaches of Yangtze River. The main minerogenetic epoches vary widely from the Archean to Quaternary, and are mainly the Late Archean to Middle Proterozoic, Variscan, and Yanshanian periods. The main 7 genetic types of iron deposits in China are metamorphosed sedimentary type（BIF）, magmatic type, volcanic-hosted type, skarn type, hydrothermal type, sedimentary type and weathered leaching type. The iron-rich ores occur predominantly in the skarn and marine volcanic-hosted iron deposits, locally in the metamorphosed sedimentary type（BIF） as hydrothermal reformation products. The theory of minerogenetic series of mineral deposits and minerogenic models has applied in investigation and prospecting of iron ore deposits. A combination of deep analyses of aeromagnetic anomalies and geomagnetic anomalies, with gravity anomalies are an effective method to seeking large and deep-buried iron deposits. China has a relatively great oresearching potential of iron ores, especially for metamorphosed sedimentary, skarn, and marine volcanic-hosted iron deposits. For the lower guarantee degree of iron and steel industry, China should give a trading and open the foreign mining markets.
文摘1.IntroductionHigh-purity elements are the basic materials in electronics,communication,aerospace,atomicenergy and semiconductor material industries.Its development is a decisive factor for high-tech in-dustries.The high-purification of non-ferrous metals is of great significance.It conduces to determining
文摘It is of great significance with the development of China’s foreign trade and the economic and trade expansion in China by foreign businessmen to get a clear understanding of the present economic situation and the 1997 economic trends in China.
文摘1.Rare Earth Resources in China1.1.Reserves and distributionChina is the country which is the richest in the world in rare earth(RE)resources of allavailable varieties of minerals and their deposits are located in vast areas in China.Reserveshave been estimated at a grand total of 36 million ton,which is 80% of the world(RE)de-posits.The majority of these deposits are concentratedly located in Baiyunebo mine of the
文摘The state of welders training in China is introduced in this paper.There are different specifications because of variable examining organizations,as the deeping of reform and openning in China, welders are trained according to variable specification to fit specific requirement.
文摘1. The Power Industry and Cogeneration in China 1.1 The Power Industry in China The power industry has developed rapidly in China in recent decades. In 1994, total electricity generation was 927.8 TWh and the total installed capacity was 199.80 GW. It is broken down as follows: hydropower 49.0 GW. 24.5 %; thermal power 148.73 GW, 74.4c/c: and nuclear power 2.1 GW, 0.7%.
文摘With the rapid development of national economy in China, pumped-storage power plant(PSPP) has developed very fast for its special stable and dynamic benefits in recent years.Because of the ever-increasing power load and its peak-to-valley ratio, customers have higherexpectation for the securityand quality ofpower supply. PSPPs are playing a role in load regulation,energy saving and reliable operation of power girds with its unique peak-shifting character.
文摘Hydropower resources in river basins are typically developed in a cascade manner. The cascade hydropower stations use water from the same river; in a sense, they form a cluster of hydropower stations which are linked together by the river stream. The dispatch and management of the cascade hydropower stations in a river basin differ from those of an ordinary single hydropower station. Without doubt, unified dispatch can facilitate the full harnessing of hydraulic resources and is in a better position to fulfill the objectives in the development of river basin. As a result, more and more river-basin cascade power stations around the world implement unif ied dispatching.
文摘THE BASIC SITUATION The Chinese govemment has always been devoting a great deal of attention to the research of diarrhoea prevention and control. Early in 1950’s we wiped out the classical cholera which had been epidemic over a century in old China, brought typhoid fever and dysentry under control by preventing them from spreading in large areas, and reduced to different extents the incidence and mortality of other types of diarrhoea. Since China is a country with a vast territory and a large population, and is greatly varied
