To enhance the stability of helicopter maneuvers during task execution,a composite trajectory tracking controller design based on the implicit model(IM)and linear active disturbance rejection control(LADRC)is proposed...To enhance the stability of helicopter maneuvers during task execution,a composite trajectory tracking controller design based on the implicit model(IM)and linear active disturbance rejection control(LADRC)is proposed.Initially,aerodynamic models of the main and tail rotor are created using the blade element theory and the uniform inflow assumption.Subsequently,a comprehensive flight dynamic model of the helicopter is established through fitting aerodynamic force fitting.Subsequently,for precise helicopter maneuvering,including the spiral,spiral up,and Ranversman maneuver,a regular trim is undertaken,followed by minor perturbation linearization at the trim point.Utilizing the linearized model,controllers are created for the IM attitude inner loop and LADRC position outer loop of the helicopter.Ultimately,a comparison is made between the maneuver trajectory tracking results of the IM‑LADRC and the conventional proportional-integral-derivative(PID)control method is performed.Experimental results demonstrate that utilizing the post-trim minor perturbation linearized model in combination with the IM‑LADRC method can achieve higher precision in tracking results,thus enhancing the accuracy of helicopter maneuver execution.展开更多
The content of total sugar, sucrose, fructose and protein in the leaves of3-yr.-old Betula platyphylla was measured after the treatment by three exogenous sugar solutions(sucrose, fructose, glucose) and three high con...The content of total sugar, sucrose, fructose and protein in the leaves of3-yr.-old Betula platyphylla was measured after the treatment by three exogenous sugar solutions(sucrose, fructose, glucose) and three high concentrations of CO_2 (700, 1 400, 2 100 μL/L·L^(-1))for about a month in 1998. The results showed that spraying three exogenous sugar solutionsincreased markedly the content of sugar and protein of leaves under 700 μL·L^(-1) and 1 400μL·L^(-1) CO_2 The effect of spraying exogenous sucrose solution was the best among the threeexogenous sugars. The treatment of spraying exogenous sugar solution and 2 100 μL·L^(-1) CO_2constrained the accumulation of total sugar and protein of leaves. There was no difference inprotein content of leaves when spraying glucose and fructose solutions under 700 μL·L^(-1) and 1400 μL·L^(-1) CO_2. The treatment of 2 100 μL·L^(-1) CO_2 concentration significantly increasedthe contents of total sugar, sucrose, fructose, and protein of leaves compared with that of the 700μL·L^(-1) and 1 400 μL·L^(-1) CO_2 except the plants spraying fructose solution. There waspositive correlation between the content of sugar of leaves and CO_2 concentration when sprayingsame exogenous sugar solution.展开更多
The main results of this paper are following theorems: (1)A left A-injective ring satisfying the ascending chain condition on right annihilator is QF ring. (2)A left A-injective ring satisfying the ascending hain cond...The main results of this paper are following theorems: (1)A left A-injective ring satisfying the ascending chain condition on right annihilator is QF ring. (2)A left A-injective ring satisfying the ascending hain condition on left annihilator is QF ring. (3)If R satisfies the following conditions: (ⅰ) r(A∩B)=r(A)+r(B), for each pair of left ils A,B;(ⅱ) rl(I)=I, for every right ideal I. Then R is semiperfect ring and has essential left s. In particular, any right CF left A-injective (or E(_RR) is projective left R-module) is QF ring展开更多
PtSnNaGa/ZSM-5 catalysts with different contents of Ga were prepared and characterized by X-ray diffraction (XRD), nitrogen adsorption, hydrogen chemisorption, ammonia temperature-programmed desorption (NH3-TPD), hydr...PtSnNaGa/ZSM-5 catalysts with different contents of Ga were prepared and characterized by X-ray diffraction (XRD), nitrogen adsorption, hydrogen chemisorption, ammonia temperature-programmed desorption (NH3-TPD), hydrogen temperature-programmed reduction (H2-TPR), and temperature-programmed oxidation (TPO) techniques. The performances of these catalysts for propane dehydrogenation were investigated. The test results indicated that the addition of Ga not only could improve the catalytic stability and propene selectivity, but also could effectively prevent the catalysts from coking. It was found that the PtSnNaGa(0.5 m%)/ZSM-5 catalyst exhibited the best performance in terms of propene selectivity and propane conversion. The high catalytic performance was most probably attributed to the presence of Ga that could strength- en the interaction between metals and the support to stabilize the catalytic active sites.展开更多
The La-ZSM-5 zeolite with different contents of La was synthesized by the hydrothermal method. The physico-chemical properties of the materials were studied. The results of FT-IR analyses indicated that La might be in...The La-ZSM-5 zeolite with different contents of La was synthesized by the hydrothermal method. The physico-chemical properties of the materials were studied. The results of FT-IR analyses indicated that La might be incorporated into the framework of ZSM-5 zeolite. The NH3-TPD analyses showed that the amount of weak acid sites of the zeolite decreased with a continuously increasing La content. Afterwards, the La-ZSM-5 zeolite was used as the support of PtSnNa catalyst for propane dehydrogenation. The test results revealed that the utilization of La- ZSM-5 zeolite could achieve a high propene conversion, and effectively inhibit the coke formation on the catalyst surface. When the content of La was 0.16%, the catalytic activity and stability of the catalyst got the best of its performance. Besides, the PtSnNa/La （0.16%）-ZSM-5 catalyst is more stable than the conventional PtSnNaLal ZSM-5 catalysts.展开更多
1 Introduction Major and profound changes have taken place in China over the past 30 years. An epidemic of cardiovascular diseases （CVD） in China is emerging as a result of lifestyle changes, urbanization, and the ...1 Introduction Major and profound changes have taken place in China over the past 30 years. An epidemic of cardiovascular diseases （CVD） in China is emerging as a result of lifestyle changes, urbanization, and the accelerated process of aging. The incidence of CVD is continuously increasing and will remain an upward trend in the next decade. Since 2005,展开更多
K2Ti2O5 and LixK2-xTi2O5 samples with varying K contents （x=0.125, 0.15, 0.3）, targeted on removal of two main environmental pollutants： PM and NOx, were synthesized by the solid state method using TiO2, KNO3 and L...K2Ti2O5 and LixK2-xTi2O5 samples with varying K contents （x=0.125, 0.15, 0.3）, targeted on removal of two main environmental pollutants： PM and NOx, were synthesized by the solid state method using TiO2, KNO3 and LiOH-H2O as starting materials and were characterized by X-ray diffractometry, scanning electron microscopy, and BET. The catalytic activity of titanate catalysts on PM oxidation was evaluated using the temperature programmed oxidation （TPO） method. The test results showed that the perovskite structure of K2Ti205 was still retained after doping a small amount of Li, and the catalytic performance of LixK2-xTi2O5 had been improved significantly compared with that of K2Ti2O5. Li0.15K1.85Ti205 catalyst had the highest catalytic activity with an ignition temperature of 210℃ and a peak temperature of 290℃. The catalytic activity of both K2Ti2O5 and LixK2-xTi2O5 under intimate contact was higher than that under loose contact. When the exhaust gas flow rate was around 100 mL/min, the catalyst samples showed a highest activity. The Li doped K2Ti2O5 could be an excellent candidate for PM oxidation due to its high oxidation activity, water stability, resistance to sulfur poisoning and economical advantages.展开更多
The extending of a cantilever and transverse moving of a drilling floor enable the jack-up to operate in several well positions after the Jack-up has pitched. The cantilever allowable load nephogram is the critical re...The extending of a cantilever and transverse moving of a drilling floor enable the jack-up to operate in several well positions after the Jack-up has pitched. The cantilever allowable load nephogram is the critical reference which can evaluate the jack-up's drilling ability, design the cantilever structure and instruct a jack-up manager to make the operations safe. The intent of this paper is to explore the interrelationships between the cantilever position, drilling floor and the loads including wind force, the stand set-back weight etc., through analyzing the structure and load characteristics of the x-type cantilever and the simplified mechanics model with the restriction of the maximum moment capacity of the cantilever single side beam. Referring to several typical position designs load values, the cantilever allowable load nephogram is obtained by using the suitable interpolation method. The paper gives a method for cantilever allowable load design, which is proved reliable and effective by the calculation example.展开更多
Activated carbons （ACs） with different surface properties were prepared from different raw materials. N2 adsorption, pH value, Boehm titration, Temperature-programmed reduction （TPR） and FTIR were employed to char...Activated carbons （ACs） with different surface properties were prepared from different raw materials. N2 adsorption, pH value, Boehm titration, Temperature-programmed reduction （TPR） and FTIR were employed to characterize the pore structure and surface chemical properties of the ACs. The results show that AC from bituminous coal （AC-B） has more meso-pores, higher pH value, more carboxylic groups and basic site than ACs from coconut shell and hawthorn（AC-C, AC-H）. Oxygen in the mixture gas has great effect on S02 catalytic oxidation/oxidation ability of AC-B. In the absence of oxygen, the adsorbed SO2 on AC-B is 0.16 mmollg and the conversion ratio of adsorbed S02 to S03 is 22.07~; while in the presence of oxygen, the adsorbed amount of S02 is 0.42 retool/g, and all of the adsorbed S02 was totally converted to SO3. This feature of AC-B is consistent with its higher pH value, basic site and the reaction ability with H2 from TPR. The conversion ratios of S02 absorbed on both AC-C and AC-H were 100%, respectively.展开更多
The reactive adsorption desulfurization of model gasoline was carried out on Ni/ZnO-HY adsorbent.The Ni/ZnO-HY adsorbent was characterized by N2adsorption-desorption test(BET),X-ray diffractometry(XRD),and temperature...The reactive adsorption desulfurization of model gasoline was carried out on Ni/ZnO-HY adsorbent.The Ni/ZnO-HY adsorbent was characterized by N2adsorption-desorption test(BET),X-ray diffractometry(XRD),and temperature-programmed reduction(TPR)analysis.The test results have demonstrated that HY-zeolite is a feasible support for Ni/ZnO components used in reactive adsorption desulfurization.The results of XRD and TPR analyses showed that most of nickel element was present as Ni2+species with only a small part existing as Ni3+species,and the Ni2+species had interactions with HY-zeolite.Under the conditions of this study,which specified a 50% ratio of HY-zeolite in the adsorbent,a Zn/Ni molar ratio of 10,and a reduction temperature of 400℃,the Ni/ZnO-HY adsorbent showed the best desulfurization performance.The sulfur capacity of Ni/ZnO-HY adsorbent could be recovered to 92.19% of the fresh one after being subjected to regeneration at 500℃,and could be maintained at 82.17% of the fresh one after 5 regeneration cycles.展开更多
This research work developed a model for the MIP riser reactor using the data collected from an industrial MIP unit.Based on analysis of flow patterns in the reactor,three models were established and a comparison was ...This research work developed a model for the MIP riser reactor using the data collected from an industrial MIP unit.Based on analysis of flow patterns in the reactor,three models were established and a comparison was made on each other.The results indicated that Model Ⅲ,which was assumed a plug flow in the first reaction zone and a gas plug flow and a continuously stirred catalyst flow in the second reaction zone,was the best.The results of this research could offer an information and guidance for optimization and development of MIP unit.展开更多
A6×19 point-contact hoisting cable was used as our research object to examine the progress of corrosion of steel wires in a laboratory,simulating the actual working conditions in a coalmine.An electrochemical met...A6×19 point-contact hoisting cable was used as our research object to examine the progress of corrosion of steel wires in a laboratory,simulating the actual working conditions in a coalmine.An electrochemical method was used to investigate the corrosion behavior of steel wires with different surface treatments of a corrosive acid solution.The results show that anode activation of steel wire mainly occurs during pre-corrosion,where the anode activation process of bare steel wires is the fastest as is their corresponding corrosion speed,while the anode activation process of oil coated steel wires and their corresponding corrosion speed are the lowest.During the intermediate and late immersion periods, a passive film is generated on the surface of steel wires,which are gradually damaged with the passage of time.Local pitting corrosion occurs easily on the surface of steel wires with a high-polarization potential. Suitable equivalent circuits were chosen to fit the electrochemical impedance spectroscopy（EIS）of steel wires over various corrosive times and different surface treatments,which indicate good fitting results. The double electrical layer charge-transfer resistance increases in the sequence：bare steel wire, untreated steel wire and oil coated steel wire and their corrosion resistance decreases in turn,which is consistent with their polarization curves.The oil layer provides a certain protective effect on untreated steel wires,but its effect is not entirely clear.展开更多
Effects of vanadium on light olefins selectivity of FCC catalysts were investigated with vanadium having different oxidation numbers （hereinafter abbreviated as Oxnum）. Molecular modeling studies showed that vanadiu...Effects of vanadium on light olefins selectivity of FCC catalysts were investigated with vanadium having different oxidation numbers （hereinafter abbreviated as Oxnum）. Molecular modeling studies showed that vanadium with low Oxnum could affect the chemical conversion of large-size hydrocarbon molecules. However, the vanadium deposited on equilibrium catalyst bad high Oxnum because of the oxidation reaction taking place in the regenerator, so an activation method to reduce vanadium Oxnum named ＂selective activation＂ was introduced. It was proved by means of Electron Paramagnetic Resonance （EPR） and Temperature-Programmed Reduction （TPR） methods that the vanadium Oxnum was decreased, when the catalyst was activated. The molecular modeling studies are consistent well with the lab evaluation results. The light olefins selectivity of activated equilibrium catalysts was better than that achieved by the inactivated catalysts. Similar results were observed with the lab vanadium-contaminated catalyst. The light olefins selectivity of the catalyst was optimized when the vanadium Oxnum was close to 2 （VO）.展开更多
基金supported in part by the National Natural Science Foundation of China(No.12032012)the Key Discipline Construction Project of Colleges and Universities in Jiangsu Province.
文摘To enhance the stability of helicopter maneuvers during task execution,a composite trajectory tracking controller design based on the implicit model(IM)and linear active disturbance rejection control(LADRC)is proposed.Initially,aerodynamic models of the main and tail rotor are created using the blade element theory and the uniform inflow assumption.Subsequently,a comprehensive flight dynamic model of the helicopter is established through fitting aerodynamic force fitting.Subsequently,for precise helicopter maneuvering,including the spiral,spiral up,and Ranversman maneuver,a regular trim is undertaken,followed by minor perturbation linearization at the trim point.Utilizing the linearized model,controllers are created for the IM attitude inner loop and LADRC position outer loop of the helicopter.Ultimately,a comparison is made between the maneuver trajectory tracking results of the IM‑LADRC and the conventional proportional-integral-derivative(PID)control method is performed.Experimental results demonstrate that utilizing the post-trim minor perturbation linearized model in combination with the IM‑LADRC method can achieve higher precision in tracking results,thus enhancing the accuracy of helicopter maneuver execution.
基金This paper was supported by the National Natural Science Foundation of China (No. 39970627) and the Key Project of State Department of Science Technology (2002BA515B05).
文摘The content of total sugar, sucrose, fructose and protein in the leaves of3-yr.-old Betula platyphylla was measured after the treatment by three exogenous sugar solutions(sucrose, fructose, glucose) and three high concentrations of CO_2 (700, 1 400, 2 100 μL/L·L^(-1))for about a month in 1998. The results showed that spraying three exogenous sugar solutionsincreased markedly the content of sugar and protein of leaves under 700 μL·L^(-1) and 1 400μL·L^(-1) CO_2 The effect of spraying exogenous sucrose solution was the best among the threeexogenous sugars. The treatment of spraying exogenous sugar solution and 2 100 μL·L^(-1) CO_2constrained the accumulation of total sugar and protein of leaves. There was no difference inprotein content of leaves when spraying glucose and fructose solutions under 700 μL·L^(-1) and 1400 μL·L^(-1) CO_2. The treatment of 2 100 μL·L^(-1) CO_2 concentration significantly increasedthe contents of total sugar, sucrose, fructose, and protein of leaves compared with that of the 700μL·L^(-1) and 1 400 μL·L^(-1) CO_2 except the plants spraying fructose solution. There waspositive correlation between the content of sugar of leaves and CO_2 concentration when sprayingsame exogenous sugar solution.
文摘The main results of this paper are following theorems: (1)A left A-injective ring satisfying the ascending chain condition on right annihilator is QF ring. (2)A left A-injective ring satisfying the ascending hain condition on left annihilator is QF ring. (3)If R satisfies the following conditions: (ⅰ) r(A∩B)=r(A)+r(B), for each pair of left ils A,B;(ⅱ) rl(I)=I, for every right ideal I. Then R is semiperfect ring and has essential left s. In particular, any right CF left A-injective (or E(_RR) is projective left R-module) is QF ring
基金supports provided by the Production and Research Prospective Joint Research Project (BY2009153)the Science and Technology Support Program (BE2008129)of jiansu Province of chinathe National Natural Science Foundation of China(50873026)
文摘PtSnNaGa/ZSM-5 catalysts with different contents of Ga were prepared and characterized by X-ray diffraction (XRD), nitrogen adsorption, hydrogen chemisorption, ammonia temperature-programmed desorption (NH3-TPD), hydrogen temperature-programmed reduction (H2-TPR), and temperature-programmed oxidation (TPO) techniques. The performances of these catalysts for propane dehydrogenation were investigated. The test results indicated that the addition of Ga not only could improve the catalytic stability and propene selectivity, but also could effectively prevent the catalysts from coking. It was found that the PtSnNaGa(0.5 m%)/ZSM-5 catalyst exhibited the best performance in terms of propene selectivity and propane conversion. The high catalytic performance was most probably attributed to the presence of Ga that could strength- en the interaction between metals and the support to stabilize the catalytic active sites.
基金the National Nature Science Foundation of China(50873026)the Science and Technology Support Program of Jiangsu Province (BE2008129)the"Six Talents Pinnacle Program"of Jiangsu Province(06-A-033) for financial supports
文摘The La-ZSM-5 zeolite with different contents of La was synthesized by the hydrothermal method. The physico-chemical properties of the materials were studied. The results of FT-IR analyses indicated that La might be incorporated into the framework of ZSM-5 zeolite. The NH3-TPD analyses showed that the amount of weak acid sites of the zeolite decreased with a continuously increasing La content. Afterwards, the La-ZSM-5 zeolite was used as the support of PtSnNa catalyst for propane dehydrogenation. The test results revealed that the utilization of La- ZSM-5 zeolite could achieve a high propene conversion, and effectively inhibit the coke formation on the catalyst surface. When the content of La was 0.16%, the catalytic activity and stability of the catalyst got the best of its performance. Besides, the PtSnNa/La （0.16%）-ZSM-5 catalyst is more stable than the conventional PtSnNaLal ZSM-5 catalysts.
文摘1 Introduction Major and profound changes have taken place in China over the past 30 years. An epidemic of cardiovascular diseases （CVD） in China is emerging as a result of lifestyle changes, urbanization, and the accelerated process of aging. The incidence of CVD is continuously increasing and will remain an upward trend in the next decade. Since 2005,
基金supports provided for this research by the Education Department of Liaoning Province of China (No. 2009T061)Ministry of Education of China (No. [2010] 1561)
文摘K2Ti2O5 and LixK2-xTi2O5 samples with varying K contents （x=0.125, 0.15, 0.3）, targeted on removal of two main environmental pollutants： PM and NOx, were synthesized by the solid state method using TiO2, KNO3 and LiOH-H2O as starting materials and were characterized by X-ray diffractometry, scanning electron microscopy, and BET. The catalytic activity of titanate catalysts on PM oxidation was evaluated using the temperature programmed oxidation （TPO） method. The test results showed that the perovskite structure of K2Ti205 was still retained after doping a small amount of Li, and the catalytic performance of LixK2-xTi2O5 had been improved significantly compared with that of K2Ti2O5. Li0.15K1.85Ti205 catalyst had the highest catalytic activity with an ignition temperature of 210℃ and a peak temperature of 290℃. The catalytic activity of both K2Ti2O5 and LixK2-xTi2O5 under intimate contact was higher than that under loose contact. When the exhaust gas flow rate was around 100 mL/min, the catalyst samples showed a highest activity. The Li doped K2Ti2O5 could be an excellent candidate for PM oxidation due to its high oxidation activity, water stability, resistance to sulfur poisoning and economical advantages.
文摘The extending of a cantilever and transverse moving of a drilling floor enable the jack-up to operate in several well positions after the Jack-up has pitched. The cantilever allowable load nephogram is the critical reference which can evaluate the jack-up's drilling ability, design the cantilever structure and instruct a jack-up manager to make the operations safe. The intent of this paper is to explore the interrelationships between the cantilever position, drilling floor and the loads including wind force, the stand set-back weight etc., through analyzing the structure and load characteristics of the x-type cantilever and the simplified mechanics model with the restriction of the maximum moment capacity of the cantilever single side beam. Referring to several typical position designs load values, the cantilever allowable load nephogram is obtained by using the suitable interpolation method. The paper gives a method for cantilever allowable load design, which is proved reliable and effective by the calculation example.
基金support from the National Natural Science Foundation of China (No.50204011)
文摘Activated carbons （ACs） with different surface properties were prepared from different raw materials. N2 adsorption, pH value, Boehm titration, Temperature-programmed reduction （TPR） and FTIR were employed to characterize the pore structure and surface chemical properties of the ACs. The results show that AC from bituminous coal （AC-B） has more meso-pores, higher pH value, more carboxylic groups and basic site than ACs from coconut shell and hawthorn（AC-C, AC-H）. Oxygen in the mixture gas has great effect on S02 catalytic oxidation/oxidation ability of AC-B. In the absence of oxygen, the adsorbed SO2 on AC-B is 0.16 mmollg and the conversion ratio of adsorbed S02 to S03 is 22.07~; while in the presence of oxygen, the adsorbed amount of S02 is 0.42 retool/g, and all of the adsorbed S02 was totally converted to SO3. This feature of AC-B is consistent with its higher pH value, basic site and the reaction ability with H2 from TPR. The conversion ratios of S02 absorbed on both AC-C and AC-H were 100%, respectively.
基金financially supported by the National Natural Science Foundation of China(No.21276086)the Opening Project of State Key Laboratory of Chemical Engineering of East China University of Science and Technology(No.SKL-ChE-11C04)
文摘The reactive adsorption desulfurization of model gasoline was carried out on Ni/ZnO-HY adsorbent.The Ni/ZnO-HY adsorbent was characterized by N2adsorption-desorption test(BET),X-ray diffractometry(XRD),and temperature-programmed reduction(TPR)analysis.The test results have demonstrated that HY-zeolite is a feasible support for Ni/ZnO components used in reactive adsorption desulfurization.The results of XRD and TPR analyses showed that most of nickel element was present as Ni2+species with only a small part existing as Ni3+species,and the Ni2+species had interactions with HY-zeolite.Under the conditions of this study,which specified a 50% ratio of HY-zeolite in the adsorbent,a Zn/Ni molar ratio of 10,and a reduction temperature of 400℃,the Ni/ZnO-HY adsorbent showed the best desulfurization performance.The sulfur capacity of Ni/ZnO-HY adsorbent could be recovered to 92.19% of the fresh one after being subjected to regeneration at 500℃,and could be maintained at 82.17% of the fresh one after 5 regeneration cycles.
文摘This research work developed a model for the MIP riser reactor using the data collected from an industrial MIP unit.Based on analysis of flow patterns in the reactor,three models were established and a comparison was made on each other.The results indicated that Model Ⅲ,which was assumed a plug flow in the first reaction zone and a gas plug flow and a continuously stirred catalyst flow in the second reaction zone,was the best.The results of this research could offer an information and guidance for optimization and development of MIP unit.
基金supported by the National Natural Science Foundation of China(No.50875252)the Program for New Century Excellent Talents in University(No.NCET-06-0479).
文摘A6×19 point-contact hoisting cable was used as our research object to examine the progress of corrosion of steel wires in a laboratory,simulating the actual working conditions in a coalmine.An electrochemical method was used to investigate the corrosion behavior of steel wires with different surface treatments of a corrosive acid solution.The results show that anode activation of steel wire mainly occurs during pre-corrosion,where the anode activation process of bare steel wires is the fastest as is their corresponding corrosion speed,while the anode activation process of oil coated steel wires and their corresponding corrosion speed are the lowest.During the intermediate and late immersion periods, a passive film is generated on the surface of steel wires,which are gradually damaged with the passage of time.Local pitting corrosion occurs easily on the surface of steel wires with a high-polarization potential. Suitable equivalent circuits were chosen to fit the electrochemical impedance spectroscopy（EIS）of steel wires over various corrosive times and different surface treatments,which indicate good fitting results. The double electrical layer charge-transfer resistance increases in the sequence：bare steel wire, untreated steel wire and oil coated steel wire and their corrosion resistance decreases in turn,which is consistent with their polarization curves.The oil layer provides a certain protective effect on untreated steel wires,but its effect is not entirely clear.
文摘Effects of vanadium on light olefins selectivity of FCC catalysts were investigated with vanadium having different oxidation numbers （hereinafter abbreviated as Oxnum）. Molecular modeling studies showed that vanadium with low Oxnum could affect the chemical conversion of large-size hydrocarbon molecules. However, the vanadium deposited on equilibrium catalyst bad high Oxnum because of the oxidation reaction taking place in the regenerator, so an activation method to reduce vanadium Oxnum named ＂selective activation＂ was introduced. It was proved by means of Electron Paramagnetic Resonance （EPR） and Temperature-Programmed Reduction （TPR） methods that the vanadium Oxnum was decreased, when the catalyst was activated. The molecular modeling studies are consistent well with the lab evaluation results. The light olefins selectivity of activated equilibrium catalysts was better than that achieved by the inactivated catalysts. Similar results were observed with the lab vanadium-contaminated catalyst. The light olefins selectivity of the catalyst was optimized when the vanadium Oxnum was close to 2 （VO）.
