Papers by Author: Lian Wei Yang

Abstract: The compound super absorbent resin was synthesized by starch, bentonite, acrylic acid and acrylamide, using microwave irradiation. Some key factors affecting the solution absorbency of the polymer such as the amount of bentonite, acrylamide, initiator and cross-linking agent have been discussed. The results showed that the optimal reaction conditions of cross-linking agent, initiator, neutralization degree, bentonite, phosphate starch are 0.045%, 0.32%, 70%, 10%, 3% when the weight ratio of acrylic acid and acrylamide was 2:1, the microwave power was 800W, the radiation time was 15min. Under the conditions, the pure water absorption rate of super absorbent resin was up to 796g/g. when the weight ratio of acrylic acid and acrylamide was 1:1, the absorption rate of 0.9% NaCl was 95g/g.

Abstract: By microwave method, a superabsorbent function composite material was prepared by grafting sodium acrylate onto straw flour using potassium persalfate (K₂S₂O₈) and N, N'-methylene bis acrylamide as an initiator and crosslinker, respectively. The effect of various preparation conditions on its water absorbency was investigated. When the straw flour content was 6%, the acrylic acid content was 20.0g, the amount of initiator was 0.4%, the neutralization degree of monomer was 80%, the reaction temperature was 70°C and the amount of crosslinker was 0.05%, the materials absorbency was 1360 times in distilled water and 152 times in 0.9% salt-water at ambient temperature. It had also high water retention. The analyses of SEM indicate that sodium acrylate is grafted on the polysaccharides of straw flour.

Abstract: Co/ WC composite powders (with 10 wt% content of Co) were synthesized by direct mechanical grinding in a rotary-vibration mill. The powders with different mill time were evaluated. WC and WC/Co composite coatings were prepared by supersonic plasma spraying. The results showed that the milled powders consist of composite particles that were formed in the first 2h of milling. Longer milling times improve the distribution of phases inside the composite particles. The formation of the composite particles involves sequential steps of deformation, fragmentation, cold welding, work hardening and piercing of particles of the hard phase in the soft phase. X-ray spectra of the sprayed coating are shown that only very weak W2C and Co6W6C peaks are observed. Compared with WC coating, the Co/ WC coating is denser, and less large pores within composite coating.

Abstract: Macroscopic lattice deformation of martensitic transformation and shape memory effect (SME) were studied by atom force microscopy (AFM), X-ray diffraction and so on. The results showed that stress induced martensitic surface relief was “N”-shaped. The surface relief was parallel distribution when deformation was less than 6%. When relief became to intercross, its height and width were far less than parallel relief in same deformation. Superior heat-recovery was discovered in parallel surface relief. The recovery ratio was very low in intercrossed relief. The macroscopic lattice deformation descends in virtue of relief intercrossed, then recovery process was forbidden, so that recovery ratio was descent.

Abstract: The Al2O3 nano-films of different thicknesses (1~100nm) were successfully deposited on the monocrystalline Si surface by using ion beam sputtering deposition. The surface topography and the component of nano-films with different thickness were analyzed. The quality of the surface of nano-films was systematically studied. When the films’ thickness increase, the studies by atomic force microscope (AFM), X-ray photoelectron spectrum（XPS） show that the gathering grain continually grows up and transits from acerose cellula by two-dimensional growth to globularity by three-dimensional growth. The elements O, Al and Si were found on the surface of Al2O3 nano-films. With the thickness of the films increasing, the content of Al gradually increases and the intensity peak of Si wears off, the surface quality of the deposited films is ceaselessly improved

Abstract: In this study, we use d remote sensing and GIS technology to estimate the value of soil conservation. The Revised Universal Soil Loss Equation (RUSLE) was used to estimate soil erosion quantity. The total amount of soil conservation of grassland ecosystem was 79.25×10⁵t/a in HulunBuir in 2006, the total value was 81.58×10⁷yuan/a, in which the economic value of soil fertility conservation, reducing abandoned farmland and reducing silt accumulation were 80.39×10⁷yuan/a, 0.694×10⁷yuan/a and 0.50×10⁷yuan/a respectively. For the different grassland types, lowland meadow was maximum, next was temperate meadow-steppe. Marsh was the minimum.

Abstract: Due to population pressure and over-grazing, ecological degradation of the rangeland in HulunBuir becomes more and more serious in past decades. To balance pasture grazing activities and ecosystem sustainability, monitoring grass productivity of the rangelands and livestock carrying capacity are very necessary. Grassland yield is the basis of developing livestock, net primary production (NPP) is an important parameters in determining carrying capacity. Using MODIS remote sensing data, we estimated the NPP of grassland ecosystem of HulunBuir in 2006. The total NPP of grassland ecosystem in HulunBuir was 2.9×10¹³ gC/a in 2006, with an average of 261.01gC/m²•a. Then we based on the estimated NPP to calculate the optimal carrying capacity which was 765.41 ten thousands sheep units. The actual carrying capacity was 1838.45 ten thousands sheep units, total overloading was 1073.04 ten thousands sheep units. The serious regions of overloading were Arong Banner with 325.45 ten thousands sheep units, Zlantun City with 270.72 ten thousands sheep units, Molidawadahanr Autonomous Banner with 254.71 ten thousands sheep units. The carrying capacity of Oroqin Autonomous Banner, Genhe City and Erguna City were scarcity, there were great potential to excavate in livestock.

Abstract: Net primary productivity (NPP) is an important indicator for vulnerability monitoring in arid ecosystem. Using MODIS remote sensing data and the improved solar energy efficiency, we estimated the NPP of grassland ecosystem of HulunBuir in 2006, and then output from the improved solar energy efficiency model was validated by the field survey data during growing season of 2006. Comparison of estimated NPP and field sampling NPP, the field sampling NPP was greater than estimated NPP, but there was better interdependency between the field sampling NPP and estimated NPP.The total NPP of grassland ecosystem in HulunBuir was 2.9×10¹³ gC/a in 2006, with an average of 261.01gC/m²•a. The average was the minimum in Xinbaerhuyou Banner, the maximum in Genhe. For the difference grassland types, lowland meadow was the maximum of unit area, the next was alpine meadow, and temperate steppe was the minimum.

Abstract: The grassland ecosystem of HulunBuir city is an important component of ecology security system in Northeast China. In this study, net primary productivity (NPP), as an improtant ecological parameter, was used to estmate the services value. Considering the characteristic of satellite imagery, it is difficult to calculate some functions. So we calculated the services value from 6 aspects, including soil erosion control, water conservation, direct production, gas regulation, nutrient recycling and atmospheric environment purification. The total services value of grassland ecosystem was estimated in RMB to be aproximately 18.47×10⁹Yuan in 2006, the average economic value of unit area was 15.4×10⁴Yuan/km². The direct production value was 1.23×10⁹Yuan/year; and the contribution rate to total value was 6.66%. The water regulation value was the maximum, 9.09×10⁹Yuan/year. Gas regulation value was 5.25×10⁹Yuan/yea. The purify atmosphere value was minimal.

Abstract: In view of the problems of current pantograph sliders of electric train，a new pantograph slider is developed for high speed train. The new pantograph slider is consisted of copper，carbon fiber, graphite and etc. The results showed the optimal technique of preparing slider : copper content 78％, carbon fiber content 2％, additive content 5％, pressure 200MPa and sintering temperature 880°C. Its resistance is very low. And its performance of friction，abrasion and impact toughness etc. is improved greatly compared with foreign immersed metal carbon slider Rh82Mb with friction coefficient reduced by 20 %，abrasion ratio decreased by 1.3 %，impact toughness increased by 1.7 times and conductance increased by 65 times.