人参风化沙育苗游离氨基酸的测定

近年来,参业生产发展很快,参业与林业争地矛盾亦日益突出,为保护森林资源,吉林省气象研究所利用风化沙进行了人参育苗研究。并对风化沙和常规的人参育苗中游离氨基酸的种类及含量进行了比较测定。

水下爆夯加密风化沙的探讨

本文根据已有工程实践资料及长江三峡工程的室内试验成果，利用爆夯加密水下抛填风化沙不仅技术先进，而且施工可行，可保证三峡工程二期围堰几百万ｍ３的填筑及几十万ｍ３风化沙的爆夯加密在较短时间内完成，且其经济指标远较其它加密措施优越，因此这种方法应是三峡工程二期围堰水下加固风化沙的主要比较方案。

Effects of peat and weathered coal on the growth of Pinus sylvestrisvar. mongolica seedlings on aeolian sandy soil

The experiment was conducted at the Ganqika Sandy Land Ecological Station in Ke抏rqinzuoyihouqi County, Inner Mongolia, in a growing season from April 28 to October 28, 2001. Peat and weathered coal were added to the aeolian sandy soil in different ratios. Two-year-old Pinus sylvestris var. mongolica seedlings and plastic pots were used in the experiment. The experimental results indicated that: 1) the peat and weathered coal could significantly improve the physical and chemical prop-erties of aeolian sandy soil, and thus promoted the growth of seedlings; 2) the effect of peat on seedling growth, including height, base diameter, root length and biomass, presented an order of 8%>10%>5%>2%>0 in terms of peat contents, and the effect of weathered coal on seedling growth presented an order of 5%>8%>10%>2%>0 in terms of weathered coal contents for height and basal diameter, 5%>8%>2% >10%>0 for root length, and 5%>2%>8% >10%>0 for biomass; 3) the effects of peat were generally greater than that of weathered coal. Meanwhile, 8% peat was the best treatment to promote the growth of P. sylvestris var. mongolica seedlings.

Informational digital diagrams applied to predict spring wind,snow,and sandstorms

Using informational digital diagrams, we analyzed the snow event that occurred on Feb 26, 2006 and the sandstorm on Apr 11, 2006 in Xi＇an. Results indicate that, under similar weather circumstances, different events evidently exhibit unique vertical structure features. Informational digital diagrams provide a method for transitional weather prediction, a problem for present extrapolative analysis system.

葛洲坝工程关键技术在三峡工程的应用及发展

葛洲坝工程于1981年通航发电,20年来运行实践证明,工程设计先进、施工质量和主要机电设备质量优良。葛洲坝工程成功地解决了一系列复杂的科学技术难题,积累了多方面的丰富经验。如工程河势规划和泥沙问题,复杂的工程基础处理问题。

Field trial on use of soybean crude extract for carbonate precipitation and wind erosion control of sandy soil

Wind erosion is a major cause of land desertification and sandstorm formation in arid and semi-arid areas.The objective of this study was to evaluate the potential of soybeans crude extract induced calcium carbonate precipitation(SICP)on reducing wind erosion risk of sandy soil.Field tests were carried out in Ulan Buh Desert,Ningxia Hui Autonomous Region,China.Results showed that the SICP method could significantly enhance the surface strength and wind erosion resistance of the topsoil.The optimal cementation solution(urea-CaCl2)concentration and spraying volume,according to experiments conducted on sandy land,were 0.2 mol/L and 4 L/m^2,respectively.Under this condition,the CaCO3 content was approximately 0.45%,the surface strength of sandy soil could reach 306.2 kPa,and the depth of wind erosion was approximately zero,after 30 d completion of SICP treatment.Soil surface strength declined with the increase of time,and long-term sand fixation effects of SICP treatment varied depending on topography.Whereas wind erosion in the top area of the windward slope was remarkable,sandy soils on the bottom area of the windward slope still maintained a relatively high level of surface strength and a low degree of wind erosion 12 month after SICP treatment.Scanning electron microscopy(SEM)tests with energy dispersive X-ray(EDX)confirmed the precipitation of CaCO3 and its bridge effect.These findings suggested that the SICP method is a promising candidate to protect sandy soil from wind erosion in desert areas.

A quantitative analysis on the sources of dune sand in the Hulun Buir Sandy Land:application of stepwise discriminant analysis (SDA) to the granulometric data

Quantitatively determining the sources of dune sand is one of the problems necessarily and urgently to be solved in aeolian landforms and desertification research. Based on the granulometric data of sand materials from the Hulun Buir Sandy Land, the paper employs the stepwise discriminant analysis technique (SDA) for two groups to select the principal factors determining the differences between surface loose sediments. The extent of similarity between two statistical populations can be described quantitatively by three factors such as the number of principal variables, Mahalanobis distance D 2 and confidence level 琢for F-test. Results reveal that: 1) Aeolian dune sand in the region mainly derives from Hailar Formation (Q 3 ), while fluvial sand and palaeosol also supply partially source sand for dunes; and 2) in the vicinity of Cuogang Town and west of the broad valley of the lower reaches of Hailar River, fluvial sand can naturally become principal supplier for dune sand.

Desertification and Blown Sand Disaster in China

Approximately 331 million ha, one-third of China＇s total land, is prone to desertification processes, leading to natural disasters and economic losses. In this study, the situation, tendency, their influences and their risk governance of desertification and blown sand disaster in China were examined using satellite images, field photographs, field data and a literature review. The desiccated areas in Lop Nor and the lower Heihe River fluvial plain covered about 50,000 km2 and 40,000 km2, respectively. In Ejina, about 100 species of vegetation became extinct. The rate of wind erosion in China was between 1,000 tons/km2/year and 2,000 tons/km2/year. There were 12 sand deserts and sandy lands, occupying a total of 710,000 km2. Salinized soils occurred across 99.1 million ha. The two main sand and dust storm-prone areas in China were the Tarim Basin and its surroundings, and the Alxa Plateau and its surroundings. From 1981 to 2007, the annual average frequency of sand and dust storms varied from 1 d to 37 d with a general increase from southeast to northwest. Since 1978, China has implemented a number of ecological construction projects that have reduced desertification from 1999 to 2004 and from 2005 to 2009, and the number of dust and sand storm days from 9.3 d between 1954 and 1959 to 4.4 d between 2000 and 2007. The results could improve understanding of desertification and blown sand disasters in China and provide valuable experiences for global desertification control.

Study of the engineering geologic feature of weathering zone of bedrock in 810 producing area of Luling Mine

For a safe extracting of the mine resource of the razor thin capping rock, a study of waterproof, sand prevention, roof fall prevention must be made. As a result, it’s necessary to master the engineering feature of weathering zone of bedrock. According to the lithology appraisal and X diffract analyses, the mineral feature of weathering zone of bedrock in 810 producing area has been studied in this article. By testing the physical mechanics index of weathering zone, we have found out some features of physical mechanic quality. Utilizing the determined result of viscosity index and slaking test, we reach a conclusion of the water stability of weathering zone, that is the weathering zone rock belongs to the type that is easily slaked when encountered water and the water stability is weak.

Sand-fixing Function under the Change of Vegetation Coverage in a Wind Erosion Area in Northern China

Using meteorological and remote sensing data and changes in vegetation cover during the wind erosion season in northern China, a revised wind erosion equation was applied to evaluate spatiotemporal variation in soil erosion and conservation since the 1990s, and to reveal the effects of the change of vegetation coverage on the wind erosion control service. The results showed that average soil erosion in northern China between 1990 and 2010 was 16.01 bil ion tons and was decreasing. The most seriously eroded areas were mainly distributed in large desert areas or low cover grasslands. Most wind erosion occurred in spring, accounting for 45.93% of total wind erosion. The average amount of sand ifxation service function for northern China between 1990 and 2010 was 20.31 billion tons. Given the influence of wind erosion forces, the service function for sand fixation cannot effectively highlight the role of sand ifxation from the ecosystem itself. The retention rate of service function for sand ifxation reveals the role of the ecosystem itself. The distribution characteristics of the soil retention rate are similar to vegetation cover, which shows a gradual decrease from southeast to northwest in the study area. Improved spring vegetation cover was observed mainly on the Loess Plateau, Qinghai-Tibet Plateau, in northern Hebei, eastern Inner Mongolia and northeast China after the implementation of ecosystem projects. The soil retention rate in most areas showed a signiifcant positive relationship with grassland vegetation in spring （r＆gt;0.7, p＆lt;0.01）. The increments of ecosystem service function for various ecological systems are different. Increments for the grassland ecosystem, forest ecosystem, farmland ecosystem and desert ecosystem are 2.02%, 1.15%, 0.99% and 0.86%, respectively.

牛金老汉的家事

1村支书赵书田的新媳妇刘茂花推开牛金家篱笆院门的时候,院子里还浮动着丝丝缕缕的夜色,牛金俩口子刚从炕上下来没多会,老婆坐在屋子里拉着风箱做早饭。

Overview of the Measures and Techniques Used to Protect Traffic Lines against Shifting Sands in China

Shifting sands are one of the main contributors to desertification in China. This paper briefly reviews the measures and techniques which are used to protect traffic lines by stabilizing and fixing sands in the desert and desertification-affected arid and semi-arid areas in north China. We introduce the types and features of these measures and techniques, including mechanical, chemical, and biological measures, and outline how they have been applied in different areas and in different traffic lines over the past six decades, from 1950 s to 2010 s, taking the Baotou-Lanzhou railway, the Qinghai-Tibet railway, and the Tarim Desert highway as examples Mechanical measures such as erecting sand-retaining wind walls and placing straw checkerboards have proved to be very efficient for stabilizing shifting sands and protecting traffic lines that pass through the desert areas. Chemical measures are not widely used in the current sand fixing systems because of their high cost and potential pollution risks. Biological measures are preferred because they exhibit much better sand fixation performance and longer duration than the former two types of measures despite their relatively high cost. A combination of different measures is usually adopted in some areas to attain better sand-fixing effects. Stabilizing sand dune surfaces with mechanical measures or irrigation from underground water or river if available helps early recruitment of some drought-tolerant plants(xerophytes). We also point out the restrictions for existing sand-fixing measures and techniques and future research orientation. This review has implications for addressing eco-environmental issues associated with infrastructure construction that is part of the Belt and Road Initiative in desert and desertification-affected arid and semi-arid areas in the Mongolian Plateau.

Investigations on Several Mechanical Problems in Windblown Sand Movement

It is very necessary for the investigation on mechanism of windblown sand movement to under- stand and find out effective measures of preventing and reducing danger of windblown sands,which al- so deals with some general characters and hot spots in the scientific forelands,such as multi-scale prob- lems,interactions among multi-physical-fields,ran- domness and nonlinearity as well as complex sys- tems.In recent years,a series of experiments in wind tunnels and theoretical modeling as well as computer simulation have been undertaken in the re- search group of environmental mechanics on wind- blown sand movement in Lanzhou University with the point of mechanical and geography intersecting view.Some original and essential progress has been achieved, which includes that the main regu- larities of charges on sand particles and the electric field in windblown sand flux and the effect of the electric field on the flux and the microwave propaga- tion are revealed,and the evolution process of windblown sand flux under the mutual couple inter- actions among several physical fields are predicted as well as the main features of Aeolian sand ripples are simulated.

Investigations on Several Mechanical Problems in Windblown Sand Movement

It is very necessary for investigation on mechanism of windblown sand movement to understand and find out effective measures of preventing and reducing windblown sand, This also deals with some general features and hot spots in the scientific forelands. such as multi-scale problems. interactions among. multi-physical-fields, randomness and nonlinearity as well as complex systems. In recent years, a series of experiments in wind tunnels and theoretical modeling as well as computer simulation have been taken by our research group （the Laboratory of Environmental Mechanics on Windblown Sand Movement in Lanzhou University ）in a cross-disciplinary （mechanics and geography） viewpoint. Several original and essential studies were explored such as the main regularities of charges on sand particles, the mechanisms of electric field in windblown sand flux, the effects induced by the electric field on the flux, the microwave propagations, the evolution process of windblown and flux under mutual couple interations among several physical fields, and the simulation of the main features of Aeolian sand ripples.