Synthesis and Application of Fe -MCM -41 Molecular Sieves : Cyclohexane Catalysis Oxidation Into Cyclohexanone
XIAO Bing,ZHANG yi
2006, 26 (1): 1-4.
Abstract ( ) PDF ( 155KB ) ( ) 　　
        Hexadecyl trimethyl ammonium bromide was employed as template agent , sodium silicate as the silica source and the solution of iron nitrate were added in the synthesis process under 55 ℃, the mesoporous molecular sieve Fe -MCM -41 was synthesized using the hydrothermal method, which was crystallized for 48 hours under 160 ℃.The products were characterized by XRD, nitrogen adsorption and desorption , IR and TG -DTA .The results show that the molecular sieve has the favourable crystal structure and the iron has been located in framework of the molecular sieve .Fe -MCM -41 molecular sieve was used as catalyst and oxygen gas as oxidant for the selective oxidation of cyclohexane .The effects of temperature , time and pressure on cyclohexane selective oxidation reaction were investigated .The conversion of cyclohexane is increased as the increasing of time and temperature , but the pressure has little effect on it .Under the conditions of reaction time being 6 hours, temperature being 180 ℃, and pressure being 2 .5MPa , the conversion of cyclohexane is 14 .0 %, the selectivity of cyclohexanone is 9 .5 %, and the selectivity of cyclohexanol is 90.5 %.
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Polymerization Process of C₈ ～ C₁₃ Alpha -Olefins Catalyzed by Boron Trifluoride
DING Hong -sheng,QUAN Cheng -guang,et al
2006, 26 (1): 5-7.
Abstract ( ) PDF ( 172KB ) ( ) 　　
    　Poly -alpha -olefins synthetic lubricant (PAO)is one of the important synthetic lubricant .The polymerization of C⁸ ～C¹³ alpha -olefins had been studied with boron trifluoride as catalyst .The effects of various kinds of technological condition , such as temperature, pressure , reaction time , various kinds of promoters and mass fraction of the promoter o n the yield of the poly -alpha -olefins synthetic lubricant w ere studied.The optimum technological conditions of poly -alpha -olefins synthetic lubricant are that the temperature is 30 ℃, the pressure is 0 .4 MPa, the reaction time is 4 hours , the promoter is n -butanol, and the mass fraction of the promoter is 0.1 %.Under the optimum technological conditions, enlarge experiment of poly -alpha -olefins synthetic lubricant was carried out with 10 L reactor .The proper ties of the poly -alpha -olefin synthetic lubricant w ere studied.The yield of the poly -alpha -olefins synthetic lubricant is 81 .42 %.The results show that the viscosity at 100 ℃ is 4 .87 mm²/ s, the viscosity at 40 ℃ is 21 .15 mm²/s , the viscosity index is 126 , the condensation point is -62 ℃.The pro ducts of synthetic lubricant have low viscosity ,low condensation point and high viscosity index .This work provides a fundamental data for studying the poly -alpha -olefins synthetic lubricant in industry .
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Microwave Synthesis and Characterization of Nanometer Cerium Dioxide
LI Li -hua,HU Zhen,et al
2006, 26 (1): 12-15.
Abstract ( ) PDF ( 157KB ) ( ) 　　
    　Nanometer cerium dioxide particles were synthesized by using advanced microwave synthesis technology , the materials included Ce(SO₄)₂·4H₂O and NaOH,the surfactant was polyglycol(PEG)which could disperse and protect the products.The effect factors in the process of preparing nanometer cerium dioxide by microwave were explored individually , and the orthogonal method was adopted to confirm the optimum process condition.The optimum process conditions include the reaction volume of PEG is 9mL, the washing volume of PEG is 7 m L, the volume of absolute alcohol is 10mL , the microwave constant pressure is 0 .14MPa , microwave power is 232 W, and the microwave radiation time is 6 minutes.The qualitative analysis of product was done by IR spectrum , the X-ray diffraction w as used to investigate its crystalline phase and structure , the simultaneous TGA -DTA instruments was used to study the thermal stability of the samples, the UV -VIS spectrophotometer was used to measure its UV -VIS absorption capability . Experiments reveal that the particle diameter is 24.9 nanometer ;it exhibits excellent absorption capability between 280 and 400 nanometer in UV ray region and high transparency between 400 and 800 nanometer in the visible region .
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 Synthesis of 3 , 4 -Dihydropyrimidin -2(1H)-Ones Using Protic Acid Surfactant and Sy nergistic Catalysis
ZHOU Hai -xia,HE Miao,et al
2006, 26 (1): 16-18.
Abstract ( ) PDF ( 137KB ) ( ) 　　
　    The yield of the classical Biginelli reaction is low(20 %～ 50 %)when hydrochloric acid is used as catalyst , but synergistic catalysis of surfactant combined with proton acid could accelerate the Biginelli reaction effectively .3, 4-Dihydropy rimidin-2(1H)-ones was synthesized under the condition of β -cyclodextrin as surfactant combined with hydrochloric acid in ethanol solution, and the condensation substrates were benzaldehyde , β -ketoacid ester and urea .The effects of substrate mole ratio , reaction time , the amount of β - cyclodextrin and other surfactants on the yields were investigated.The results show that the yield of 3 , 4 - dihydropyrimidin -2(1H)-ones is up to 92 %, under the conditions of 1.0∶1 .2∶1 .5 mole ratio of benzaldehyde , β -ketoacid ester and urea , 2.5mmol β -cyclodextrin, 0.25mL hydrochloric acid, 25mL ethanol, and 8 hours refluxing time .
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Recovering Oil From Used Waste Clay by Surfactant Method
MO Ya -nan,GUO Da -guang
2006, 26 (1): 19-21.
Abstract ( ) PDF ( 176KB ) ( ) 　　
   　Waste clay was prepared in proper mass ratio by fresh clay and poo r quality diesel oil.The efficiency of the oil recoveryfrom the waste clay w as investigated .The recovery processing conditions of waste clay are as follows :the mass ratio of liquid and solidis 2∶1, stir ring temperature is 95 ℃, and stirring time is 30 minutes .Under the above conditions , the survey of the surfactants andthe surfactants' confected types w as made .The results show that the oil recovery effects of the compound surfactants are better thanthat of the single surfactant .The compound surfactants types and the mass ratio of the compound surfactants were determined.Whenthe mass ratio of the selected anionic surfactant and the selected nonionic surfactant is 4∶1, the oil recovery rate reaches 88.82%.Furthermore , the color and quality of the recovery oil is good .
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Non -Hydro -Dewaxing Technology of Hy drocracking Tail Oil
SHI Wei -w ei,CAO Zu -bin，et al
2006, 26 (1): 22-25.
Abstract ( ) PDF ( 179KB ) ( ) 　　
        Using hydrocracking tail oil as feed stock, the pilot -scale experiment was done on FS -J1 fixed catalytic bed reaction apparatus with self -made FL -J non -hydro -dewaxing catalyst .The catalytic performance , production distribution and product property were studied under the temperature of 340 ～ 400 ℃ and space velocity of 2 ～ 5 h ^-1.The results show that production distribution is good, the solidification point of diesel fuel reaches -29 ℃, and the solidification point of lubricating oil reaches -16℃ when reaction temperature is 400 ℃, reaction space velocity is 2 h^-1 at normal pressure and without hydrogen .The catalysts are treated by steam after 4 .5 ×103 hours, the activity of catalyst is partly reactivated , the reaction temperature is reduced about 20 ℃. FL-J no n-hydro -dewaxing catalyst has good application foreground.
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Adsorption of Lead (Ⅱ)by Discarded Brewer' s Yeast
WANG Zhan -yong,ZHANG Jing,SU Ting -ting
2006, 26 (1): 26-29.
Abstract ( ) PDF ( 155KB ) ( ) 　　
        The biosorption action of lead(Ⅱ)by beer discarded brewer' s yeast w as studied for exploiting new types of biosorbent . The optimal adsorption conditions of lead(Ⅱ)by discarded brew er' s yeast were determined at first.Initial pH value is 5 , initial mass concentration of lead(Ⅱ)is 50 mg/ L , the mass concentration of yeast is 1g/ L, adsorption temperature is 30 ℃, and adsorption time is 60 minutes.Under the above conditions, the adsorption rate of lead(Ⅱ)by discarded brewer' s yeast can reach to 93 .50 %.The desorptive experiment of discarded brewer' s yeast adsorbed lead(Ⅱ)w as performed.I t shows that the preferable desorbent is HCl (concentration is 1mol/ L), the desorption rate of which reaches to 54.59 %.According to calculation , it is demonstrated the adsorption lead(II)process of discarded brewer' s yeast is in accordance with both Langmuir and Freundlich adsorption model, and better complied with Langmuir adsorption model.The blank and lead(I I)-biosorption yeast were studied by infrared spectra analysis, and the difference of which was compared .
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Orthogonal Test Research of the SiO₂ Sol Stability
WANG Xing -li,QIU Guo -min,ZHANG Ke -zheng
2006, 26 (1): 30-33.
Abstract ( ) PDF ( 138KB ) ( ) 　　
　　The silica sol is a kind of colloid solution, silica drop dispersing in water or solvents.Silica sol was prepared by sol-gel method from tetraethoxy silane (TEOS)with the ethanol as solvent and dilute hydrochloric as catalyst .Orthogonal test was used to study the effects on silica sol stability such as the mole ratio of water and TEOS , the mole ratio of EtOH and TEOS, pH , the mole ratio of DMF and TEOS and the temperature .The effects of the above factors can be used to control the silica sol stability .The results show that the mole ratio of EtOH and TEOS exhibits significant effect on the silica sol stability , the silica sol stability increases with the increasing mole ratio of EtOH and TEOS .The next is the mole ratio of DMF and TEOS .DFM makes gelation time become long .The other effects are least .The effect of temperature is the least, sol stability decreases with the increasing temperature .
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Application of Solid Superacid Catalyst SO₂ ^-4 /ZrO₂ in Acetalization
WANG Jing -yun,ZHANG Shu -jiang
2006, 26 (1): 34-37.
Abstract ( ) PDF ( 164KB ) ( ) 　　
        By using nanometer oxides as precursor , solid superacid catalyst SO₂ ^-4 /ZrO₂ with Hammett constant less than -12 .14 was prepared .The catalyst SO₂ ^-4 /ZrO₂ was used for the ace talization of benzaldehyde with acetic anhydride .The results of IR, GC ,NMR and melting point measurement show that the purity o f the target product of acetalization is very high .The influence of calcining temperature , concentration of sulphuric acid, immersing time and activating temperature on the yield of aldehy deacetal was investigated by uniform design.The optimum conditions for obtaining the highest yield of aldehyde acetal are as follows :the calcining temperature is 300 ℃, concentration of sulphuric acid in immersion liquid is 4 .5mol/ L, immersing time is 1 hour , activating temperature is 305 ℃.The yield of aldehy deacetal is 93.6 %.The analysis of IR and TG indicates that the absorptive capacity of SO₂ ^-4 on SO₂ ^-4 /ZrO₂ is large .The reusing experiment of catalyst show s that the catalyst can be reused more than ten times with high catalytic activity .Its treatment and regeneration are easy .
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Development and Engineering Application of Hydraulic Asphalt Products
QU Tao, LIAO Ke -jian,et al
2006, 26 (1): 38-41.
Abstract ( ) PDF ( 159KB ) ( ) 　　
　　By blending -slight oxidation and slight oxidation process, the optimum process conditions could be obtained by testing the effects of penetration of feedstock , oxidation temperature , air velocity flow and oxidation time on hydraulic asphalt products using domestic and imported crude oil as feedstock .A high quality hydraulic asphalt with good high or low temperature performances and aging resistance used in water conservancy construction w as developed.The test results show that the permeability coefficient of imported hydraulic asphalt mixture and domestic hydraulic asphalt mixture are 1.14 ×10 ^-9 cm/ s and 2 .35 ×10^-9 cm/s;the Marshall stability after aging are increased 14.80 % and 14.28 %;the Marshall value under 60 ℃ are decreased 18.10 % and 6 .19 %;water stability factors are 0.874 and 0 .969 ;and the flexure ratio of bend test under 16.4 ℃ are more then 5 .4 % and 3 .7 %, respectively .It is demonstrated that the asphalt concrete is a hydraulic asphalt with good bending ability , aging resistance ,water stability and penetration resistance .
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The Natural Polymer Adsorptions Adsorbing Copper Ion and Nickel Ion in Water
YAO Dong -mei,ZHAO Shan -lin,et al
2006, 26 (1): 42-44.
Abstract ( ) PDF ( 163KB ) ( ) 　　
　    In order to remove copper ion and nickel ion from the water more effectively , the adsorbing effects on copper ion and nickel ion of the three kinds of adsorbent chitosan , peat and marine algae had been studied.Meanwhile , it also made a study about the effects on the adsorption rate of copper ion and nickel ion of the pH of solution, adsorption time , mass concentration of adsorbent and mass concentration of metal ion.The results show that the effect on adsorbing copper ion of the chitosan is the best and the adsorption rate can even reach 98 % when the chitosan is under such conditions that pH is 6, mass concentration of adsorbent is 3 g/L and the adsorption time is 120 minutes .And the effect on adsorbing nickel ion of the peat is the best and the rate of adsorption is 80 %w hen the peat is under such conditions that pH is 6 , mass concentration of adsorbent is 1 g/ L and the adsorption time is 120 minutes .
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Macrokinetics Studying on Catalyic Sy nthesis of TAME by β Zeolite
WANG Li,WANG Hai -y an,CHEN Jin -peng
2006, 26 (1): 45-47.
Abstract ( ) PDF ( 139KB ) ( ) 　　
　    In order to produce environment - friendly new formulated gasoline to meet stricter requirement of environmental protection and to supply the data for the development of β zeolite catalyst and the design of reactor , the macrokinetics of TAME liquid -phase synthesis catalyzed by β zeolite was studied, where isoamylene was etherified with methano l.Two -compo nent modified β zeo lite molecular sieve(mass fraction of phosphorus is 1 % and mass fraction of molybdenum is 3%)was used as catalyst to synthesize TAME with methanol and isoamylene in the batch reactor without the effect of internal diffusion or external diffusion .The kinetic experimental data is obtained at the temperature range from 60 ℃ to 90 ℃ and the pressure 1.0MPa .According to Arrehenius equation and adopting the no nlinear fitting method to deal the experimental data , macrokinetic equation is obtained .The verification of the model shows that the macrokinetic equation of etherification of tert -olefins and kinetic parameters can well describe the process of the etherification reaction.
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Development of Ex tremity Healing Crack Frost With Angelica Oil
YANG Fan,ZHANG Bo,et al
2006, 26 (1): 48-51.
Abstract ( ) PDF ( 197KB ) ( ) 　　
        Ethanol and water was used as solvent to infuse angelica powder , then angelica oil w as obtained by refluxing and distilling extractant.Fourier transform infrared spectroscopy analysis shows that angelica oil contains the efficient component ligustilide . Angelica oil was used as the natural additive for the extremity healing crack frost to produce the senior cosmetic , which w as oil -in - water .The effect of mass of emulsifying agent 1802 and angelica oil on the capability of extremity healing crack frost was studied.By checking the mass of the product and practical probation , it prov es that w hen mass of emulsifying agent 1802 is 3 .0 g and mass of angelica oil is 1 .5 g in 200 g extremity healing crack frost , the product has the perfect curative effect on preventing the extremity crack.According to the national standard requirement , the product reaches the distinct purpose of capability stabilization, pliancy skin, boosting rift heal up
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Strength Reliability Calculation for Formation Center Tester System
ZHAO Bin,WANG Mao -ting
2006, 26 (1): 52-54.
Abstract ( ) PDF ( 200KB ) ( ) 　　
    　Formation center tester(FCT)is made up of hydraulic power joint, double PACKER joint , opposing infuse joint, numeric pump exhausting joint , sensor joint and sampling tube joint .The six joints are in series .Because its working environment hard , it is necessary to have reliability analysis for it .The reliable of FC T was calculated by using K-OUT-OF-N model, and the reliable of each joint w as worked out by using Monte-Carlo method .The narrow casting formula of reliable on FCT test system was calculated based on probability theory .The approximation calculus formula of reliable on FCT was calculated by using abate probability being q Bernoulli test sequence , probability formula and property of increasing convex function.The reliable of FCT was calculated respectively by using narrow casting formula and approximation calculus formula .The results are 0 .918 and 0 .915 .Calculating results show that FCT has high reliability
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Reliability Analysis of Heat Exchanger' s Fatigue Life
CHEN Jin -mei,WANG Mao -ting
2006, 26 (1): 55-57.
Abstract ( ) PDF ( 191KB ) ( ) 　　
　    According to the fatigue failure analysis of heat exchanger , on the basis of probability theory , combining the method of estimate of definite fatigue fracture mechanics , the formula to calculate the fatigue crack propagation life of heat exchanger' s components was deduced.The uncertainty and randomness of main assessment parameters were considered :initial crack size , practical working load , fracture toughness, mechanical intensity and coefficients.The random variables having some certain distributions were calculated with random sample by Mote -Carlo simulation method.A computer program was developed by using numerical integration method, and the fatigue life under given reliability and credit degree was solved .The result was compared with the fatigue life gained by theory computation method .The fatigue life in different initial crack sizes and different fracture toughness was compared , and an example was given.Analysis result shows that Mote -Carlo simulation method can reflect objectively the uncertainty of assessment parameters and overcome the shortcoming s of certainty assessment methods .So it plays a significant role in engineering application .
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Ex trusion Characteristic' s Analysis of Multiple -Screw Reactors Based on CFD
ZHU Xiang -zhe, CHEN De -rong, XIE Yu -jun
2006, 26 (1): 58-62.
Abstract ( ) PDF ( 390KB ) ( ) 　　
　    The flow of melt poly ethylene in double -screw extruder , “ —” -shaped tri -screw ex truder , triangular tri -screw extruder and four -screw extruder was analyzed by means of ANSYS/FLOTRAN .The special study focused on the central area of reactor' s flow path of triang ulartri -screw extruder and four -screw extruder .Ex trusion characteristic of four types of reactors was compared.The results show that a large velocity gradient emerges in the intermeshing region of the screw reactors, which is helpful to mix materials sufficiently .The four reactors have different numbers of intermeshing regions .Double -screw reactor , “ —” - shaped tri-screw extruder , triang ular tri -screw extruder and four -screw extruder have one, two , three , and four intermeshing regions respectively .With the increase of the number of intermeshing regions, the mixing ability of materials is enhanced gradually . Triang ulartri-screw extruder and four -screw extruder have special structure, that is, central region.Materials in the central region form circumfluence , which promotes the mixing effect and prolongs the mixing time of materials in the central region .Through calculation , the materials cannot be hold up in the central area .For double -screw extruder , “ —” -shaped tri -screw ex truder , triangular tri -screw extruder and four -screw extruder , flow rate , back flow rate , coefficient of back flow rate and average rate of shear are incremental gradually .It is verified in theory that the multiple -screw extruders have good material transpor tation and mixed ability .Multiple -screw extruder is fitter for polymer processing .
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Optimizat ion of Running Scheme With Long Distance Heated Crude Oil Pipeline
WU Ming,WANG Jin -hua,et al
2006, 26 (1): 63-65.
Abstract ( ) PDF ( 144KB ) ( ) 　　
        To the heated crude oil pipeline w hose transportation plan is fixed , the cost of transporting oil consists of power consumption cost of oil pump and fuel cost of fire furnace .It is important to decrease the cost of transporting oil under the premise of accomplishing safely and timely transporting task and making the total consumption minimal .To decrease energy consumption, taking the minimal sum of thermal energy consumption and power consumption as the objective function , a running model of long distance heated crude oil pipeline was set up.Two -layer nesting method was used to solve the model , that is, its principle is to calculate all possible pump running schemes as outer layer nesting , and to optimize inlet temperature of inner layer nesting by dynamic planning method and total energy cost is computed.To travel different schemes will get different total energy cost .Among all energy cost, the minimal one is an optimal solution.According to the model, a cor responding software has been programmed which provides a decision-making basic for optimizing transmission of long distance heated crude oil pipeline
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Research on Crashworthiness of the Typical Thin Walled Beam
GAO Xiao -qing,YOU Guo -w u,XIE Yu -jun
2006, 26 (1): 66-69.
Abstract ( ) PDF ( 354KB ) ( ) 　　
　　 Automobile crashworthiness is mainly determined by energy absorption characteristics of thin walled beam' s components in automobile structure .In order to meet the needs of automobile crashworthiness during the design , thin walled beam' s components in automobile structure w ere taken as research objects.Aiming at collision deformation characteristics, HyperMesh and LS -DYNA were used to simulate the collision process here .The w hole process was analyzed , which thin walled beam and bumper collide with rigid wall in the forward direction.The influence of simulation and computing result was analyzed with choosing different parameters. Comparing the simulation result with that of real frontal collision , the finite element model w as verified to be correct .According to simulation result and the characteristics of energy absorbability , some cor responding improved measures were put forward o n the basis of this.
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Implementation of Casting Process CAD System
Lv Bai -lin，YAN Yong -fei
2006, 26 (1): 70-73.
Abstract ( ) PDF ( 474KB ) ( ) 　　
        Taking Visual FoxPro6 .0 as a system development tool, how to use its database function and visual design method was described.A practical casting process CAD system with friendly interface was developed to introduce scientific design method into CAD system .This system can help and guide users to make technological planning according to elected scientific process design method.Instead of a processing engineer , a computer pro gram solves complicated calculating problems and inquiring problems about a large number of process data to make techno logical planning more scientific and mo re reasonable .It improves design quality and design efficiency , shortens the developing period for new products, and workouts conveniently technology documents such as casting process sheet and saves documents.
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Model and Calculation of Pipeline Rapture Failure Probability
WANG Wei,XIE Yu -jun
2006, 26 (1): 74-75.
Abstract ( ) PDF ( 151KB ) ( ) 　　
        Taking pipeline files and test reports as original materials, and with spot investigation and observation, the pipeline rupture failure was analyzed by adopting “ failure analysis system for in -service pressure pipeline” .The safety situation of pipeline defects was combined with its failure risk.Based on current test data of defects, a rational probability model was chosen to calculate failure risk probability of the pipeline .It' s very helpful to know the safety situation of pipeline , make a proper plan for examining and repairing , enhance pipeline maintenance and ensure the equipment working safely and stably .
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Disaster Recovery Project for Short Message of Personal Access Phone System
JIANG Dong,WEI Hai -ping
2006, 26 (1): 76-80.
Abstract ( ) PDF ( 191KB ) ( ) 　　
　    The essentiality of disaster recovery for consecutive operation w as introduced .Several methods of disaster recovery , main principles and design schemes were given.Through analyzing the logic structure of short message platform of personal access phone system (PHS), functional request for disaster recovery system was put forward.According to functional request for disaster recovery system , the logic structure of disaster recovery system was determined.The test data package w as designed to verify whether is the system malfunctions.To test the data changes of different members in data package decided net situation among cur rent functional modules and between functional modules and monitor modules , and work situation of all function modules.The data change rules to arise breakdown were given .In terms of rules , switch condition between the main module and the backup module was set .While a breakdown that the system can get rid of automatically appears , the system provides a sound alarm and the breakdown is eliminated automatically .When a breakdown that the system cannot fix appears, the system informs the administrator by a shor t message or E-mail to restart the system
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Kinematic Simulation of Machine Par ts Based on VRML
LI Hao,ZHANG Yan
2006, 26 (1): 81-83.
Abstract ( ) PDF ( 320KB ) ( ) 　　
　    Through introducing briefly the definition , characteristic of virtual reality modeling language (VRML)and the design procedure in the course of virtual product design , it proves that visual reality (VR) technology is no t o nly feasible in the virtual product desig n, but also ge ts good results.On the basis of this, throug h a virtual pro duct design instance , how to use VRM L to realize the kinematic simulation of the virtual products w as explained in detail .First of all , solid models throug h the three - dimensional model softw are was set up and ex ported with DXF file .Throug h VRML output interface provided by tool software such as 3DS MAX, WRL file was generated .Then WRL file w as edited in order to realize the kinematic simulation effects of machine parts.Thus, it is helpful to learn the structure of the mechanical par t , solid shape and movement characteristic .
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Design and Implementation of Short Message Service Platfo rm System
WANG Wei -min,LIU En
2006, 26 (1): 84-86.
Abstract ( ) PDF ( 172KB ) ( ) 　　
        Short message service play s a mo re and more important role in information industry .The principle of data exchange was introduced between the SP of Netcom SMS and Netcom SMSC , the SP of Netcom SMS and the user terminals of mobile telephones.The design idea of multi -protocol and multi -gateway short message platform was put forth based on CNGP, CMPP and SGIP protocol.The expansibility of short message platform was researched.The implementation method of subordinate SP interface and access-model of integrating different platforms were given .Users can access short message platform by using either Web or PC terminals.The design principle and implementation method of the SP' s short message value -added service were described .The system has run for over one year .I t has been proved that the system is reliable , secure , accurate and quick and gains the anticipative result .This system provides referenced values for the designs of all kinds of short message service platforms.
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Linearization Technology of Adaptive Pre -Distor tion for Power Amplifiers in OFDM Systems
SHEN Qing -bo, WANG Ai -qiang, DING Yuan -ming
2006, 26 (1): 87-90.
Abstract ( ) PDF ( 276KB ) ( ) 　　
　    In the orthogonal frequency division multiplexing (OFDM)transmission system , an adaptive pre-distortion method for high power amplifier (HPA)w as studied .A Wiener model was adopted to describe the input -output relationship of HPA.In the model, a linear dynamic characteristic is followed by a memory -less nonlinear static element that can be approximated by using complex power series expression.In order to compensate the nonlinear distortion in the HPA, a pre-distorter (PD) that has a Hammerstein structure is constructed as an inverse system of the HPA.The unknown parameters of the PD were identified by RLS algorithm .The algorithm converges fast while it is applied to OFDM system .The effectiveness of the adaptive pre -distortion was observed in MATLAB simulation.The simulation results show that the adaptive pre -distortion can realize effectively the linearization from the input of PD to the HPA output .
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A New Cont inuous Method for Solving Convex Prog ramming Problems
LU Yong -jie,SONG Dai -cai
2006, 26 (1): 91-93.
Abstract ( ) PDF ( 193KB ) ( ) 　　
    　Consider the convex programming problems min f (x ), s .t .gi(x )≤0(i =1 , 2 , … , m), w here x ∈ Rn and f(x), gi(x):R n ※ R are twice continuously differentiable convex function .Based on a new class equivalent condition of convex programming problems, which was first presented by Fischer , a new continuous method was put forward to solve the problem .K -K -T points of convex programming were found by path computing New ton homotopy equation, and the convex programming problems were solved.Its global convergence was proved.Finally , the method was validated with example.
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The Best Conf idence Interval of Failure Rate Parameters Proportion on Censored Data(Ⅱ):Equivalence of the Best Confidence Interval and UMA U Confidence Interval
GENG Gui -zhen,TONG Yi
2006, 26 (1): 94-96.
Abstract ( ) PDF ( 149KB ) ( ) 　　
     The parameter being estimated by using UMAU confidence interval, this method can describe precision by making an interval, which includes the smaller probability of wrong value .That is to say , when the true value of parameter is θ and unequal with θ′, Pθ(θ(X)≤θ′≤θ(X))should be small.The interval length was considered by a more direct method to describe precision, giving the conception of possessing uniformly minimum mean length confidence interval (the best confidence interval).The equivalence of two different confidence intervals was posed by some correlative knowledge .The theory of the best interval estimation is improved , which provides the theory base for application , such as studying about the best confidence interval estimation of failure rate parameters proportion on censored data .
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