Rice is one of the most important food crops contributing about 40% of the total food grain production in China. Out of about 110 million hectares of area sown food crops, 28% is covered by rice. Since 1980s, the shortage of water resources has become an important problem for agricultural production in rice planing areas and many water saving regimes for rice have been tested, advanced, applied and spread in different regions of China. In this paper, based on the results of experiment and the experience of spread of these new irrigation regimes, the following four main kinds of water saving irrigation regimes in China have been classified viz. (1) combining shallow water depth with “wetting” and “dry” (SWD), (2) alternate wetting and drying (AWD) ,(3) semi-dry cultivation (SDC) and (4) rainwater storage (RS). The standards of field water control and potential of saving water, increasing rice yield and water productivity of these regimes are introduced and explained. The selection and attention points of application for the four regimes are presented and the causes of sustainable saving water and increase in water productivity and the environmental impacts by adopting these regimes are analyzed and discussed.
This paper has set up a mathematical model of economic development, which combines the linear program model and the input-output model, based on analyzing the systematic structure and program objectives in the farm of Shengli Oil Fields. It has achieved satisfactory results in eight years by means of the mathematical model to guide the economic production in the farm and proved that the established model is right.
In recent times, one of the primary scientific objectives of physical geodesy is to determine the geoid with centimeter level and to develop the ultra high global earth’s gravity field model，and for this purpose satellite gravity gradiometry is one of the most promising techniques. This paper first comments on the main progress of satellite gravity gradiometry, and then discusses some theories and methods for refining the earth´s gravity field using satellite gravity gradiometry data.
In this paper,the virtual enterprise agility evaluation index system was put forward, meanwhile, a new AFHW model which combines improved analytic hierarchy process (AHP) with improved fuzzy and gray and matter element method (FHW) was presented in order to carry out experts consultation and the virtual enterprise agility measurement. At last, an enterprise case was used to demonstrate with the developed support system that virtual enterprise agility measurement was effective.
Almost all the cracks in mass concrete are surface cracks. Full-section cracks and deep-level cracks are mainly developed from early surface cracks. This paper describes the characteristics of the surface cracks of mass concrete firstly. Then a semi-infinite plane model for surface temperature calculation is compared with infinite model. The temperature of surface zone in mass concrete under different boundaries is controlled by semi-infinite model, and is transferred to and calculated by an equivalent infinite model under certain conditions. If the temperature declining duration of air is no more than the critical time when the disturbed front perforates half-thickness of the infinite plate, it may be expressed as multi-line process approximately, and most importantly the temperature in surface zone of concrete can be calculated with the formula educed by infinite model. With 400 mm × 400 mm × 220 mm concrete specimens, the temperatures in surface zone are experimentally researched under outside environment, which has attested the method presented. It is also found that the new method to describe declining process of air temperature is more accurate than the method prevailing, and there does exist an opportunity to develop a physical model for the temperature process of mass concrete within a short period of time.
Based on analyses of fluvial process and the reason of the shoal deformation, the shoals of the middle Yangtze River can be divided into three kinds, i.e. the shoals of the braided reach, the shoal of the straight transitional reach and the shoal of the bend. The influences of cut-off of the lower reach of Jingjiang River and river bed evolution on the shoal due to the set-up of Gezhouba Dam are briefly presention. The regulation principle and the regulation engineering preliminary layouts of the typical shoal are discussed.
The history and architecture of intelligent transportation system is reviewed. After the excellence of mobile agent is introduced，the application of mobile agent in intelligent transportation system is focused from the following fields： network management, wireless communication, traffic control system, simulation system and graphics information system.
Most of the research work on rockburst in the world is now concentrated on the prediction,control and prevention of rockburst. Few work has been done on how to proceed the rockburst research in developing a new mine with rockburst tendency. In this paper, the authors create a general working procedure to develop a new hard-rock burst-prone mine. The general procedure is divided into 6 steps： initial determination of burst tendency; study of the proneness to rockburst of typical rock samples ;in-situ rock stress measurement; possibility of strain burst in the mine; principles in the selection of mining techniques; setting up seismic monitoring system. The above study results lays a theoretical foundation for applied research of deep hard-rock burst-prone mining.
By analysis on the stability of covered karst base, a kind of way, which can be adopted to predispose the covered karst base using pressure grouting, is developed in this paper. The evaluation of grouting effect indicates this way can be carried out economically and technically.
This paper proposes a dynamical fast IP-routing lookup algorithm (DFR). This algorithm uses special data structure to construct index table, and can support inserting, deleting and updating route dynamically. DFR algorithm accesses memory at most four times and at least two times for a route look up. DFR is suitable not only for hardware implementation but also for software implementation.
This paper discusses the relationship between IS014000 standard and the sustainable development of the state-owned enterprises. Establishing the environmental management system according to IS014000 standard is an important aspect for the enterprises´ sustainable development,and is of great strategic importance. The benefit from implementing IS014000 standard in the enterprises is obvious. But only a few enterprises have done so. The difficulties existing in these enterprises are analyzed and some suggestions on how to.establish the environmental management system are proposed.
On the basis of field experiments conducted by authors for a few years, the research results published by many others were collected and analyzed. It was showed that the water effect and fertilizer effect on crop production were related to experiment method. The result obtained from field experiments was opposite to that from simulated experiments because the concept of “water” in the experiments was not the same. The result of rainproof-shed experiments or pot experiments didn’t coincide with the field situation. In many cases, nutrient shortage was still the limit factor to increase crop yield in arid zones in Northern China. The effect of irrigation water on crop production depended on the soil water content before sowing, precipitation during crop growing, soil fertility and irrigation time, etc. At the present water resources situation, the main way to increase crop yield in most farmland of arid zone in Northern China was increasing nutrients supply. Enhancing the storage of rainfall during summer fallow period and raising soil water content before sowing were important for winter wheat production.
In building fires, smoke is one of the primary factors which result in death. This paper summarizes the researches on experiment and theory about the smoke toxicity, and introduces the method for evaluation of smoke toxicity. Some suggestions on smoke toxicity research are also presented in this paper.
A New 3G broadband mobile wireless Internet has been proposed. New 3G system has some specifications of “Beyond IMT - 2000”，but using 3G frequency and inside 3G framework. Fixed telecommunication operator can cut down the cost of feature rich voice and mobile multimedia services, by using existing fixed broadband IP network infrastructure to deploy broadband mobile wireless Internet. This is opportunity for China to lead the trend of broadband mobile wireless Internet in the world.