Search

With the rapid development of economy and a large number of energy consumption, the countries all over the world are faced with the depletion of fossil energy resources. Meanwhile, a large number of fossil energy extraction cause geological disasters frequently and the greenhouse effect, which lead to global warming, acid rain and other serious environmental problems. As a representative of the biomass energy, crop straws have advantages of wide distribution, large amount, low price and cleaning, which will be an ideal choice in the future. But it is hard to be efficiently used because of the special structure of crop straws. Through fermentation engineering and gene engineering, people can greatly improve the efficiency of utilization of crop straws, which offers a very promising way to make a breakthrough for energy consumption.

The equipment manufacturing industry accelerate the pace of development in Shaanxi province in recent years, and industrial scale jumped significantly boosted the regional industry economy. This paper calculated the industrial influence coefficient and the sensitivity coefficient of the equipment manufacturing industry, and analyzed the current situation and development trend of industry association in equipment manufacturing industry in Shaanxi province based on the table from 1997 to 2007 of Shaanxi province and 2007 input-output table of China. The results show that Shaanxi Province ripple effect equipment manufacturing industry decline, and there is disparities between Shaanxi Province and the national development level in the 27 industrial sectors. Shaanxi Province equipment manufacturing industry level has much room to improve.

With the use of representative observed wind speed data for a whole year in Jiuquan field in Gansu province of Hexi Corridor ,we analysed the characteristics of ten-minutes wind speed, diurnal wind speed, monthly wind speed variation , as well as the influence of the wind power change rate in different time periods and diurnal variation in four seasons. Studies have shown that ten-minutes short-term wind turbulence characteristics was more obvious, with some randomness , but mainly exhibited typical diurnal characteristics of variation. In addition to mean state of wind conditions, there were sustained gale, short-term gale, continued small wind, regular small wind appeared. Monthly variation of wind speed is characterized by the "three peaks and three valleys" , showing the regular change that wind speed was larger in spring and summer , and it was smaller in autumn and winter. Daily fluctuation of wind electricity generation in four seasons presented similar trends, it was a peak-valley feature, valley generally appeared between 9-11 a.m., the peak occurred between 5-7 p.m..Wind power got larger between 1 and 11 p.m., this period was the peak electricity needed, wind power added can significantly ease the power grid pressure and will has significant positive effect for the power grid control. Ten-minute power variation was relatively stable, with the time interval increased, variation in electricity generation of one day rate increased gradually.

Single phase of Ba3Y1-xEuxB3O9 (0.05 ≤ x≤ 0.35)samples was prepared by the solid state reaction. The crystal structure, the surface, the particle size and luminescence properties were characterized by X-ray diffractometer, scanning electron microscopy and spectrophotometer. The results showed that the obtained samples with the particle size from 0.3 to 1.5 um were hexagonal structure. Monitored by 592 nm emission, the excitation spectra of Ba3Y1-xEuxB3O9were dominated by the charge transfer band of O2-→Eu3+ peaking at about 259 nm until x= 0.15; the transition from 7F0 to 5L6 level of Eu3+ at about 395 nm was maximum after x> 0.15. The strongest emission peak due to the 5D0→7F1transition of Eu3+ was all located at about 592 nm in the emission spectra of Ba3Y1-xEuxB3O9, and the maximum emission was obtained at x= 0.15 and 0.3 under 254 and 395 nm excitation, respectively. The excitationprocess under the two excitation energies was analyzed. It indicated that only the centrosymmetric lattices could be excited under 254 nm excitation; both the centrosymmetric and noncentrosymmetric positions could be excited by 395 nm, accordingly, the ratio of the red emission (5D0→7F2) to the orange one (5D0→7F1) increased, leading to a better chromaticity of the phosphors.

The electrically controlled birefringence of nematic liquid crystal BL-009 was measured by polarized interference method. The influence of LC absorption effect, the birefringence variation, is discussed in this paper. The experiments results showed the influence to birefringence is big in infrared region. Not only the birefringence value is greatly different with that of unconsidering absorption effect, but also the gradient changing of birefringence curves is obvious. Furthermore, the electrically controlled birefringences of two conditions are compared when the absorption coefficients of ordinary light and the extraordinary light are nearly same and greatly different. The analysis demonstrated the approximate method of absorption coefficient is feasible.

The traction characteristics of lubricant is one of the important parameters of the dynamic performance of bearings design .This paper chose three significant factors affecting the traction coefficient：temperature、load and rotate speed. Test results showed that the traction coefficient under the high load is significantly higher than under low load from room temperature to 135 °C. After more than 135 °C, the traction coefficient under the low load is higher than under the high load. It illustrated that the grease was sensitive to temperature but it reflected high temperature stable performance.The optimum conditions were obtained by Design-Expert software optimization : temperature for 235°C、load for 2800.00N、rotate speed for 183.17r/min and in this time the traction coefficient is at 0.547 in this test. It shown that the grease fitted the low speed and heavy load equipment.

Exfoliated graphite with large expanding volume (EV) was prepared by two-step intercalation, in which the mixture of nitric acid and phosphoric acid, and that of nitric acid and acetic acid were employed as intercalating agent step by step, and potassium permanganate was used as oxidant. Its preparation conditions were optimized by orthogonal experiment and parallel experiment, and its microstructure was analyzed by scanning electron microscope. The results show that the optimal preparation conditions for the first step intercalation are as follows: the mass-volume ratio of natural graphite (NG) to mixed acid is 1: 4, the volume ratio of nitric acid to phosphoric acid is 1: 2, the mass ratio of NG to potassium permanganate is 1: 0.2, and the reaction temperature is 20~30°C for 40~60 minutes. Those for the second step intercalation are as follows: the mass-volume ratio of acidized graphite (AG) to acetic acid is 1: 5, the mass-volume ratio of AG to nitric acid is 1: 1.5, the mass ratio of AG to potassium permanganate is 1: 0.15, and the reaction temperature is 20~30°C for 40~60 minutes, the EV is 450ml/g under the conditions listed above. The interlayers of graphite are fully opened and become a worm-like fluffy rope.

The solar optical collector based on rotary parabola mirror for solar optic fiber lighting is discussed in this paper. By this reflection method, the chromatic aberration can be avoided. The performance of solar collecting and fiber coupling are simulated by Tracepro software. The results showed this system can collecting soar lights with high efficiency and has high light concentration ratio. The solar lights can be coupled into optic fiber with low loss. An interesting results is found that the concentration ratio decreased with the increased curvature ratio between ellipsoid surface and parabola surface.

The toluene soluble (TS) fraction prepared from a middle-temperature coal tar pitch was subjected to a series of thermal treatments at the various temperatures from 410 °C to 470 °C for different periods of time. The samples obtained after heat treatment was quenched to ambient temperature. Mesophase spheres were separated from the quenched samples using washing oil and quinoline. The kinetics of mesophase sphere formation of the TS fraction was studied, based on the data derived from the time-dependent changes in the mesophase sphere content. It was clarified that the mesophase sphere formation of TS fraction was an autocatalytic type reaction. The rate law and the rate constants for the mesophase sphere formation at holding temperatures of 410°C, 430°C, 450°C and 470°C were determined. The rate constants of the mesophase sphere formation follow the Arrhenius equation. The Arrhenius parameters of the mesophase sphere formation are 200.2 kJ mol-1 of the activation energy and 2.71x1012 % -1 h-1 of the pre-exponential factor. The treatment temperature had a greater effect on the formation of mesophase spheres than the treatment time.

Two kinds of exfoliated graphite have been prepared from graphite flake and graphite powder, and their preparation conditions were respectively optimized by orthogonal experiments and parallel experiments. The effect of graphite size on the characteristics of exfoliated graphite was researched. The microstructure of two kinds of exfoliated graphite was measured by SEM. The results show that the optimal preparation conditions for exfoliated graphite flake are as following: the mass-volume ratio of graphite to mixed acid is 1: 4, the volume ratio of nitric acid to phosphoric acid is 1: 2, the mass ratio of graphite to potassium permanganate is 1: 0.1, and the reaction temperature is 25°C. For exfoliated graphite powder, the optimal mass ratio of graphite powder to potassium permanganate is 1: 0.22, and the consumption of oxidant for exfoliated graphite powder is more than that for exfoliated graphite flake. The longitudinal expansion of graphite flake is more apparent than that of graphite powder and leads to a worm-like fluffy rope.

According to the characteristics of compacted snow-ice, the formation types and microstructure of compacted snow-ice were analyzed to know the snow clearing performance and rule and laid the theoretical foundation for related design of snow clearing equipment. In addition, the microscopic snow clearing performance, physical and mechanical properties were described and further research was proposed, which have provided a scientific basis for technology research and equipment development in the field of snow clearing.

Taking the patent literature in the field of the 3G mobile communication in Derwent Innovation Index (DII) as the research object, this paper utilizes CiteSpace and Σ index to conduct analysis on key technologies of technical evolution in the 3G mobile communication system. Then, the key technologies from 1994 to 2009 are separated into four periods. Next, interpretations are formulated to study these key technologies represented by Derwent manual codes. Finally, this paper illustrates the key technologies and their main evolutional paths in different periods.

Thermo-mechanical experiments were carried out to study the effect of deformation speed and temperature on the behaviour of a non-quenched and tempered steel during hot forging. And an effective method for correction of friction was used to amend the tested flow stress, Meanwhile, the constitutive equations of flow stress-strain for TL1438 steel during hot forming was established based on the amended flow stress and hyperbolic sine which includes Zener-Hollomon parameter, and related parameters of TL1438 during hot forming was obtained by analyzing the data.

According to the similar characteristics of structure, geometry and constraints conditions in the same type of extrusion process, the intelligent design system of a square tube aluminum profile extrusion forming process was established in this paper based on the VB programming language, with using parametric programming language APDL provides by ANSYS software. The parameterized optimization design plan of pre-treatment and post-processing of ANSYS analysis during a square tube aluminum extrusion forming process was achieved, and the program of a three-dimensional model of the extrusion die under Visual Lisp environment was also programmed. The human-computer interaction intelligent design system which combined with pre-processing of semi-finished product, finite element analysis of extrusion die strength, extrusion die temperature field analysis, structural optimization of the die was realized. The research results show that the system can provide program decision-making, structural design, performance analysis and graphics treatment for the actual extrusion productions of square tube aluminum extrusion process, which reduced the design time of the technical staff, and saved design cost.

The orientation of the hydrocarbon chains and functionally important chromophore of copper (II) phthalocyanine (CuPc) derivatives are discussed by spectrum assessment methods in ordered thin films. The attention is focused upon the monolayer and multilayer films of CuPc derivatives that are symmetrically and asymmetrically substituted CuPc biosimulation systems. On the basis of infrared (IR) transmission, polarized IR, reflection–absorption (RA) IR spectroscopy and surface enhancement resonance Raman spectra (SERRS) study, following conclusions are given. The hydrocarbon chains of CuPc in the film are in hexagonal or pseudohexagonal subcell packing, and the CH2 asymmetric vibrational vector is oriented with respect to the substrate surface. The macrocycle of CuPc on the Ag substrate is oriented parallel to the surface, and the RA spectroscopy can distinguish the two CH2 stretching modes of benzene cycle. All these studies and results are useful to provide an insight into the nanostructure of the thin films of other kinds of compounds.

A QI-free coal tar pitch prepared by solvent extraction from a soft coal tar pitch was subjected to a series of thermal treatments at a predetermined temperature for different holding times. The development of mesophase was discussed in terms of its size and content in the heat-treated pitches. Results showed that the size and yield of the dispersed mesophase spheres in the isotropic matrix strongly depended on the holding temperatures. When the holding temperature was less than 400 °C, only a few of small spheres formed in the mesophase pitches. However, when the holding temperature was over 420 °C, the diameter and yield of mesophase spheres in the heat-treatment pitches increased progressively with increase of the holding time. Treatment at 440 °C for 4h led to 19.9 % of the yield and the average sphere radius was 4.5-100 . In the SEM photograph of mesocarbon microbeads obtained from the heat-treated pitches using soxhlet extraction. Many small flaky particles and sporadic rugby ball-shaped particles were observed as well as a large number of spherical particles.

12 RC columns specimens are divided 4 groups which have different eccentricities. Each group has 4 specimens, The first specimen was just made of reinforced concrete. The second was wrapped with 3 lays CFRP. The third had steel fibres added to it. The last was reinforced with steel fibres and wrapped with CFRP.The results showed that the introduction of fibres as well as wrapping the specimens with FRP improve the strength of concrete,especially its ductility.

In order to study small size three dimensional shape processing of electro jet machining, the micro-channel principle is introduced firstly. Moreover, narrow groove processing experiment design and construction process is described, and experimental purpose is to change the cycle times to research the rule of groove width and depth. The experimental results indicate that when the width of the groove reaches a certain value, it will be stabilized and fluctuate around the value. However, with the increasing of the cycle number, groove depth increases. If cycle times are less than 7, the overall shape of the groove is a part of an approximate ellipse, otherwise it is changed but the bottom shape of the groove is still a part of an approximate ellipse.

In order to change surface morphology and contact angle of part, abrasive jet method is discussed in the paper. Glass, steel and titanium are used to study its surface morphology by the processing of abrasive to jet the surface. In addition, the extent of its impact of processing method is studied with different abrasive size. Experiment method and environment are also introduced, and experiment shows that contact angle of glass changes from 14.9° to 93.8° (Titanium and steel also have different degrees of diversification). According to experiment of the method, abrasive jet methods affects contact angle, and it has the value of further research.