Model Test Study on the Improved Filling Embankment in Permafrost Regions_Latest Science Articles

The results showed that improved graded structured embankment is a kind of effective structure forms to protect permafrost.1. It is studied about the styles and causes of damage of roadbed, effective measures to protect roadbed in the permafrost regions. It is thought that the key is the actions of soil, temperature and water to control the damages of roadbed, if one of the three factors is mended, the damages will be controlled and the measure can protect the permafrost.
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The Effect of Excessive Phosphate Fertilizer on Mineral Nutrient Uptake of Chinese Cabbage Species

Phosphorus is one of the necessary elements for plants. The available phosphorus content in the soil has been continuously increasing with the extensive application of phosphate fertilizer in China's agricultural production. The phenomenon of excessive application of phosphate fertilizer in facility agriculture is more universal. Excessive application of phosphate fertilizer is not only a waste of resources, increasing production costs, and also increase the risk of pollution of the environment. In addition, crop production, even the quality of crops and particularly the content of other nutrients and biological effectiveness will be affected in high phosphorus status. Calcium and zinc have a decisive function on human growth and metabolism. How to improve Ca and Zn contents of vegetable and absorbable Zn for human is signality to improve vegetable commodity value and further human health.A lot of phosphate fertilizers were applied in vegetable production with a negative impact on growth and nutrient uptake of vegetables. For these reasons, the growth and nutrient uptake of Chinese cabbage species were studied under excessive phosphate fertilizer by the pot experiment and field experiment, so we can explore the mechanism of mineral nutrients absorption and transportation in the plant, which was ordered to provide the basis of high yield, good quality (human health) and scientific application of phosphate fertilizer in Chinese cabbage species production. The results were as follows: The application of phosphate fertilizer significantly increased the biomass of rape and Chinese cabbage, while there was no yield response when phosphate fertilizer rate was increased.Proper amounts of phosphate and calcium fertilizers can promote the growth of rape, while it may affect the rope growth when phosphate and calcium fertilizer rate was increased.There was no significant effect on rape growth when the phosphate and zinc fertilizers were applied.The total P in rape and Chinese cabbage shoot and root was increased gradually with the increase of phosphate fertilizer rate, while the total N, K was not changed. There was a positive correlation between the concentration of total P and application of phosphate fertilizer in plant shoot and root. The total N, P, K in rape shoot and root had no significant change with the increasing of zinc. Phosphorus was absorbed luxuriously with excessive rate of phosphate fertilizer.The total Ca, Zn concentrations in rape and Chinese cabbage shoot were decreased with the increasing application rate of phosphate fertilizer. There was a negative correlation between the total P and the total Ca, Zn concentrations in rape and Chinese cabbage shoot. The total Ca in rape and Chinese cabbage root had no significant change with the excessive phosphate fertilizer. The total Ca, Zn concentrations in rape were increased respectively with the increase of calcium or zinc fertilizer rate. There was a positive correlation between the application of phosphate fertilizer and P/Ca, P/Zn in rape and Chinese cabbage shoot.There was a positive correlation between the phosphate fertilizer rate and soil Olsen-P concentration. The phosphate fertilizer rate showed no significant effect on soil available zinc, while the soil available zinc was increased with the application of zinc, and the soil available zinc was increased gradually with the increase of zinc fertilizer rate.

Effects of Biogas Residue on the Nature of Substrate and Growth of Tomato in Greenhouse

In this experiment,three compound substrates with biogas residue and Coal cinder,as well as pure biogas residue and pure coal cinder were used as substrate for greenhouse tomato cultivation.The treatments were as follows:(T1) pure coal cinder,(T2) 1 biogas residue + 3coal cinder(ⅴ/ⅴ),(T3) 1 biogas residue + 1 coal cinder,(T4) 3 biogas residue + 1 coal cinder,(T5) pure biogas residue.The experiment was taken by potted plants and the pot was 6 liter.The experiment had 5 treatments,each treatment with 5 pots,one plant each pot,and 3 replicates,and it was designed by randomized block. The physical and chemical properties,enzyme and microbiology of the substrate and the tomato plant growth and development,fruit quality and yeild were determinated.The major results were as follows:1.Biogas residue increased the value of pH and EC of substrate.In the course of plant growth, the value of pH in substrate changed differently,and the pH value of T1 and T2 increased slghly, While the pH value of T4 and T5 decreased slightly,that was the of pH value in substrates with higher content of biogas residue increased,while the pH value in substrate with higher content of coal cinder decreased during the growth of tomato plant.The main reason for the pH increasing was that:first, decomposition of biogas residue released plenty of nutrients,and the more residue biogas the more nutrients were released;second,the transpiration of tomato plants relatively increased,both of which had increased the Ca2+,Mg2+ and other ions' accumulation in substrates.The EC value of T1,T2,T3 decreased,of which the EC value of T3 was appropriate and decreased little,and the EC value of T4 and T5 increased first and decreased later,which reflected that biogas residue had characteristics of slow and long-lasting nutrient releasing.As result of containing large biogas residue,the EC value of T4 and T5 were as high as 3.14 ms·cm-1、3.39 ms·cm-1 respectively which led to a certain degree of salt accumulation It was entirely feasible to use a certain percentage of biogas residue and coal cinder as compound substrates for soilless cultivation,and T3 had the best properties,with bulk density between 0.46g·cm-3 and 0.48g·cm-3,EC value between 1.95 ms·cm-1 and 2.58 ms·cm-1x.2.Biogas residue improved the number of microorganisms in substrate.The results showed that the number of bacteria,actinomyces,fungi,cellulose-decomposing bacteria increased with the increase of the content of biogas residue in substrates;as compared with pure coal cinder substrate, substrates with biogas residue significantly increased the number of various types of microorganisms, especially improved the distribution of rhizosphere microorganisms in soilless culture substrate.Pure biogas residue treatment had a largest effect on microorganisms,which had the most number of bacteria,actinomyces,fungi,cellulose-decomposing bacteria,they were 8.40～20.85×107cfu·g-1、3.2～46.00×106cfu·g-1、26.00～62.02×104cfu·g-1、0.94～14.03×106cfu.g-1 respectively.Biogas residue promoted the proliferation of microorganisms to speed up the decomposition of organic matter and nutrients fixed to improve the effectiveness and utilization of nutrients.3.Biogas residue improved the activity of enzyme in substrate.The effects of different substrate treatments on the activity of enzyme showed that,as compared with pure coal cinder,substrates with biogas residue enhanced the activity of phosphatase,invertase,urease proteinase,cellulose significantly, in general,the activity of enzyme enhanced as the content of biogas residue increased in substrate,and the activity of invertase and urease were highest,in T5,while the activity of proteinase and cellulose were highest in T4.Substrate enzymes involved in biochemical processes in substrate,were closely related to the release and storage of nutrients,as well as the formation of humus,substrate structure and physical properties,as a result they could improve substrate activity and ability of nutrients transformation.4.Biogas residue increased tomato plant's height,stem diameter,leaf number and root activity. Tomato plants in substrates with more biogas residue had more vigorous stronger growth on height, stem diameter and leaf number.Biogas residue increased the root activity of tomato plants,highest record of root activity occurred in T4,followed by T5、T3、T2,and there were no significant differences with T4,but T4、T5、T3、T2 were significantly higher than T1 by 118%、67%、63%、20%respectively.5.Biogas residue improved tomato fruit's quality and yield.Biogas residue improved tomato fruit soluble sugar content,lowered titratable acid content,and increased the sugar/acid ratio,of which T3 was highest and reached 6.24;but biogas residue had little effects on vitamin C.Biogas residue increased tomato yield,T4 had the highest yield,followed by.T5、T3、T2,and the yield of T4,T5, T3,T2 were all significantly higher than the pure coal cinder treatment by 200%,190%,142%,129% respectively。6.In compound substrates,it is appropriate for tomato cultivation in greenhouse when the volume ratio of biogas residue is between 50%and 75%.

Energy Security and Contemporary International Relations_Latest Science Articles

The concept of energy security occurs after oil becomes the dominating energy source. Energy security mostly refers to oil security. Energy security is a traditional security conception, as well as a non-traditional security conception. The traditional characteristic means the competition for oil supply among countries, including the control and military occupancy of oil production regions.
Energy Security and Contemporary International Relations_Latest Science Articles

Research on development strategy of forestry in Shanxi Province_Latest Science Articles

The development of the forestry economy cannot be isolated from the domestic and international market. In order to study the development strategy of forestry economy, firstly we should understand the changing situation both home and abroad. Secondly, the importance of further study on international and domestic forest industry should be attached equally.
Research on development strategy of forestry in Shanxi Province_Latest Science Articles

Controllable Soft Template for the Synthesis of Gold Nanoparticles_Latest Science Articles

At present, nanotechnology is the pioneering research fields and controllable synthesis of nanoparticles with special size and morphology is one of the most important components. It is well known that nanomaterials are different from the conventional materials due to the size, morphology, and the atom ratio of surface and bulk phase of particles, etc, and are widely and significantly used in such fields as photonics, microelectronics, magnetism, catalytic properties and biology. The formation of nanostructures is a new cross-field of colloid and interface chemistry and material science and also is one of the most active research fields.
Controllable Soft Template for the Synthesis of Gold Nanoparticles_Latest Science Articles

The Research and Application of Digital Signature_Latest Science Articles

The information security has become more and more crucial with the development of computer and network technologies. The digital signature is one of key techniques in information security, especially in the authentication, data integrity, and non-repudiation. It has been widely used in military, communication, e-commerce and e-government, etc., and will become more and more popular after the e-signature law is put in practice.The main interest of this dissertation is on the theory and method of digital signature and its application.
The Research and Application of Digital Signature_Latest Science Articles

Research on Proxy Caching and Stream-Scheduling Technology in Video-on-Demand System_Latest Science Articles

Research on Proxy Caching and Stream-Scheduling Technology in Video-on-Demand System_Latest Science Articles

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Study on BTDA-ODA Polyimide Nanofiber Prepared by Electrospinning

Electrospinning, a unique characteristic of easy operation, is one of best methods to make nanofibers. Electrospun membranes are able to form a large surface-to-volume ratio, highly porous mesh, highly length-diameter ratio and uniform fiber improves performance for many potential applications. For example, fabrics are suited to sorbing material and filtering material, because of their super adsorption, excellence filter capacity and good heat preservation, fabrics also be developed to fibers which have many functions such as antisepsis, radiation resistance, flame retardance and shielding. Aromatic polyimides, as a high performance functional fibers material, have marked excellent physical and chemical properties like thermal stability, dielectric property, radio resistant property, fire resistance, high strength, high modulus and nonpoisonous. The polyimide(PI) nanofiber was prepared by electrospinning the PAA solution, followed by thermal imidization and carbonisation. Imidized webs generated crosslinking and aromatic heterocyclic structures and carbonized with yields from 50% to 70%. The PI nanofiber has enormous potential value and will be a very promising precursor of carbon nanofiber.In this paper, different solid contents of BTDA-ODA Polyamic acid (PAA) solution were prepared with different solvent as DMF, DMAc and NMP. The non-woven membranes of polyimide for insulation are prepared by electrospinning the polyamic acid solution, followed by thermal imidization, carbonisation. Imidized webs were carbonized in the temperature range from 600℃to 1000℃under a nitrogen atmosphere. The images of fibers were characterized by scanning electron microscopy and transmission electron microscopy, heat-resistant quality of fibers was characterized by Thermogravimetric Analysis (TG) and phase structures were characterized by wide angle X-ray Diffraction (WAXD). The results showed that average diameter of PI nanofibers with DMF system (voltage was 15kV, receptor distance was 20cm and solid contents of solution was 25%)was the thinest from 150 to 250nm, diameter of PI nanofibers after heat treatment was from 300 to 500nm, bending, twisting and adhesion phenomenon were most serious within the fibers after imidization. however, PI non-woven membrane which prepared by PAA electrospun solution synthesized with NMP indicated a relatively high thermal stability, electrospining went again stcrystal structure of PI nanofiber, and it was little changed after heat treatment.

Development of Polyimide-based Carbon Nano-fiber Membrane

Polyimide(PI), as a kind of high-performance engineering material, possesses excellent physical and chemical properties. It has been widely used in microelectronics packaging, high temperature adhesive and composite, etc. High voltage electrospinning technology having advantages of simple technology and convenient operation.The diameters of fiber with continuitie ranged from several decade nanometer to hundreds nanometers. Polyimide-based carbonnano-fiber was prepared by high voltage electrospinning technology is of great potential value in application.This article based on structure and properties of polyimide, using pyromellitic dianhydride(PMDA) and bis(4-aminophenyl)ether(ODA) as monomer to prepare polyamide acid in N,N′-dimethylacetamide, and utilize high voltage electrospinning technology to prepare polyamic acid nano-fiber membrane which was further imidized into polyimidenano-fiber membrane, then use polyimidenano-fiber membrane as precursor to prepare polyimide-based carbonnano-fiber membrane through high-temperature carbonization process. Fiber diameter and non-woven pore size distribution were controlled by eletrospinning technological conditions. Scanning electronmicroscopy(SEM) and transmission electron microscopy (TEM) were utilized to investigate the surface morphology characteristics, Thermogravimetric analysis(TG), X-ray Diffraction (XRD) and infrared analysis(IR) were used to analysis and forecast structure.The results showed that polyimide-based carbonnano-fiber membrane possesses excellent thermal stability. SEM analysis shows that with the carbonation temperature increased, fiber diameter decreases gradually, distribution change narrowlly, mainly located between 100～200nm; when carbonization temperature reached 1000℃, Filamentous carbon content in polyimide-based carbon nano-fiber membrane is 96.16%. Fiber film start deoxy when temperature reached 600℃, and the structure of a graphite like formed temperature reached 700℃, after 700℃the combination of the heterocyclic may be produced to remove sulfur nitrogen oxide, then form continuous aromatic heterocyclic compounds, with temperature continue increased to 900℃fused ring aromatization happen, hexagonal carbon layer with graphite-like structure gradually increased.

The Uniform Local Asymptyotics of the Overshoot of a Random Walk with Heavy-Tailed Increments

It is well known that much attention has been paid to issues of the uniform local asymptotics of the overshoot of a random walk with heavy-tailed increments. Asmussen et al. (2003) has got a special result of local asymptotics of the overshoot of a random walk which has some conditions of moment. Rencently, Tang (2007) has investigated the non-local asymptotics of the overshoot of a random walk. In the first chapter of this paper, we introduce some fundmential knowledge about our paper. Furthermore, we fall back a lot of results which have been got before and give the aim of our paper. In the second chapter, we obtain the uniform local asymptotics of the overshoot of a random walk with heavy-tailed increments. When the overshoot is in (x + y, x + y + T) for some 0＜T＜∞, we discuss the asymptotics for two cases about y, respectively. Firstly, y≥f(x) for any positive function f(x)→∞as x→∞; secondly, y∈[0, N] for any 0＜N＜∞. Based on above results, we discuss them further and get a result of the uniform local asymptotics of the overshoot of a random walk for the case y≥0. The obtained results require certain uniform requirements for y. At last of this paper, we give a corollary and some remarks. We illustrate that the two results of the second chapter are meaningful by the corollary, and these remarks show the direction of our further research.

Merit Function Method for Structured Monotone Variational Inequalities

This paper presents a merit function method for structured monotone variational inequalities.Numerical results illustrates the efficiency of this method.1.Since 1960s,the theory and algorithms for finite-dimensional variational inequalities developed rapidly.Variational inequalities and complementarity problems have been developed an important field in applied mathematics.They have been widely used not only in nonlinear programming but in differential equation,mechanics,cybernetics,game theory,economic equilibrium theory,social and economic model,etc.Therefore,variational inequality and its application have become a focus in mathematics.2.In Chapter 3,we constructed a merit function based the model for structured monotone variational inequalities.We transformed the original problem to an optimization problem which possesses a very simple structure for calculation in our method.At last,we gave the global convergence condition.3.In Chapter 4,we introduced some algorithms for variational problems.Some numerical examples with ball constraints or box constraints were given.Numerical results verified the validity of the method provided in chapter three.