Methyl methoxyacetate(MMAc)and methyl formate(MF)can be produced directly by heterogeneous zeolite-catalyzed carbonylation and disproportionation of dimethoxymethane(DMM),with near 100%selectivity for each process.Des...Methyl methoxyacetate(MMAc)and methyl formate(MF)can be produced directly by heterogeneous zeolite-catalyzed carbonylation and disproportionation of dimethoxymethane(DMM),with near 100%selectivity for each process.Despite continuous research efforts,the insight into the reaction mechanism and kinetics theory are still in their nascent stage.In this study,ZEO-1 material,a zeolite with up to now the largest cages comprising 16×16-MRs,16×12-MRs,and 12×12-MRs,was explored for DMM carbonylation and disproportionation reactions.The rate of MMAc formation based on accessible Brönsted acid sites is 2.5 times higher for ZEO-1(Si/Al=21)relative to the previously investigated FAU(Si/Al=15),indicating the positive effect of spatial separation of active sites in ZEO-1 on catalytic activity.A higher MF formation rate is also observed over ZEO-1 with lower activation energy(79.94 vs.95.19 kJ/mol)compared with FAU(Si/Al=30).Two types of active sites are proposed within ZEO-1 zeolite:Site 1 located in large cages formed by 16×16-MRs and 16×12-MRs,which is active predominantly for MMAc formation,and Site 2 located in smaller cages for methyl formate/dimethyl ether formation.Kinetics investigation of DMM carbonylation over ZEO-1 exhibit a first-order dependence on CO partial pressure and a slightly inverse-order dependence on DMM partial pressure.The DMM disproportionation is nearly first-order dependence on DMM partial pressure,while it reveals a strongly inverse dependence with increasing CO partial pressure.Furthermore,ZEO-1 exhibits good catalytic stability,and almost no deactivation is observed during the more than 70 h test with high carbonylation selectivity of above 89%,due to the well-enhanced diffusion property demonstrated by intelligent-gravimetric analysis.展开更多
The extraction conditions of aluminum by the disproportionation process of A1C1 in vacuum were investigated using alumina and graphite as raw materials, including reaction temperature, pre-reaction and condenser struc...The extraction conditions of aluminum by the disproportionation process of A1C1 in vacuum were investigated using alumina and graphite as raw materials, including reaction temperature, pre-reaction and condenser structure. The results show that the extent of the reaction between alumina and carbon increases with increasing reaction temperature at 1643-1843 K; however, the extraction rate of aluminum increases firstly, and reaches the highest at 1743 K, and then decreases with rise in reaction temperature. The pre-reaction of alumina and carbon increases the extraction rate of aluminum. The impurities C, AlaC3 and A1203 in the aluminum product are reduced with reducing the contact surface of the aluminum with CO and with decreasing the condensation temperature, depending on the structure of the condenser.展开更多
The formation conditions of C, Al4C3 and Al2O3 in the Al Cl disproportionation process in vacuum to produce aluminum was investigated by thermodynamics analysis. It is demonstrated that the required temperatures for t...The formation conditions of C, Al4C3 and Al2O3 in the Al Cl disproportionation process in vacuum to produce aluminum was investigated by thermodynamics analysis. It is demonstrated that the required temperatures for the reactions to form these impurities, the disproportionation of CO and the reactions of metallic aluminum with CO, decrease with decreasing pressure. The lg pCO-1/T diagram of metallic aluminum-CO system agrees with the experimental results, indicating that the reaction rate is very high and this system in vacuum is approximately in equilibrium; therefore, the equilibrium diagram can be used to predict the possible reactions in this system in vacuum.展开更多
A high-efficiency method is developed to in-situ synthesize nanocrystalline TiC powders,nanorods,and nanosheets by using equimolar ratio of Ti powder and acetylene black,multiwalled carbon nanotubes(MWCNTs),and graphe...A high-efficiency method is developed to in-situ synthesize nanocrystalline TiC powders,nanorods,and nanosheets by using equimolar ratio of Ti powder and acetylene black,multiwalled carbon nanotubes(MWCNTs),and graphene,respectively,as precursor in eutectic Na Cl-KCl molten salt at 800–900℃for 2–3 h.Higher temperature and longer duration are more beneficial for TiC preparation.In addition,mechanism of TiC formation was investigated by linear scan voltammetry.Results indicate that nanocrystalline TiC is in-situ synthesized by reaction between Ti atoms,which come from disproportionation reaction of Ti(Ⅱ)species in the molten salt,and C atoms on the surface of carbon sources.展开更多
Shape-selective catalysts for the disproportionation of toluene were prepared by the modification of the cylinder-shaped ZSM-5 zeolite extrudates with chemical liquid deposition with TEOS （tetraethyl orthosilicate）....Shape-selective catalysts for the disproportionation of toluene were prepared by the modification of the cylinder-shaped ZSM-5 zeolite extrudates with chemical liquid deposition with TEOS （tetraethyl orthosilicate）.Various parameters for preparing catalysts were changed to investigate the suitable conditions.The resulting cata-lysts were tested in a pressured fixed bed reactor and characterized by SEM （scanning electron microscopy）.The conversion of toluene and para-xylene selectivity were influenced remarkably by the n（SiO2）/n（Al2O3） ratio of ZSM-5 zeolite,the type and amount of deposition agent,acid and solvent used,and the time and cycle of deposition treatment.TEOS was proved to be a more efficient agent than the conventional polysiloxanes when the deposition amount was low.The catalyst prepared at the suitable conditions exhibited a high para-xylene selectivity of 91.1% with considerable high conversion of 25.6%.SEM analyses confirmed the formation of a layer of amorphous silica on the external surface of ZSM-5 zeolie crystals,which was responsible for the highly enhanced shape-selectivity.展开更多
The carbothermal reduction-chlorination-disproportionation of alumina in vacuum was investigated by XRD and thermodynamic analysis. The experiments on alumina and graphite at 1643-1843 K in vacuum were carried out. Th...The carbothermal reduction-chlorination-disproportionation of alumina in vacuum was investigated by XRD and thermodynamic analysis. The experiments on alumina and graphite at 1643-1843 K in vacuum were carried out. The results demonstrate that AlCl3（g） reacts with Al2O（g） or Al（g） generated from the carbothermal reduction of alumina to form AlCl（g）, and the AlCl（g） disproportionates to aluminum and AlCl3（g） at a lower temperature and the reaction rate of AlCl（g） reaches 90% at 980 K and 100 Pa. The aluminum can absorb CO to catalyze its disproportionation to C and CO2, and react backward with CO to form Al4C3, Al2O3, C and CO2, resulting in the aluminum product containing C, Al4C3 and Al2O3. The impurities in the aluminum product decrease as the AlCl（g） disproportionation temperature decreases. AlCl3 condenses at a temperature approximated to the room temperature.展开更多
A new kinetic model for commercial unit of toluene disproportionation and C9-armatiocs transalkylation is developed based on the reported reaction scheme.A time based catalyst deactivation function taking weight hourl...A new kinetic model for commercial unit of toluene disproportionation and C9-armatiocs transalkylation is developed based on the reported reaction scheme.A time based catalyst deactivation function taking weight hourly space velocity(WHSV)into account is incorporated into the model,which reasonably accounts for the loss in activity because of coke deposition on the surface of catalyst during long-term operation.The kinetic parameters are benchmarked with several sets of balanced plant data and estimated by the differential variable metric optimiza- tion method.Sets of plant data at different operating conditions are applied to make sure validation of the model and the results show a good agreement between the model predictions and plant observations.The simulation analysis of key variables such as temperature and WHSV affecting process performance is discussed in detail,giv- ing the guidance to select suitable operating conditions.展开更多
The surface disproportionation reaction mechanism of aluminum subchloride on the aluminum （100） surfaces has been investigated by the plane-wave density functional theory （DFT）. Three kinds of possible reaction me...The surface disproportionation reaction mechanism of aluminum subchloride on the aluminum （100） surfaces has been investigated by the plane-wave density functional theory （DFT）. Three kinds of possible reaction mechanism of AlCl disproportionation reaction on the aluminum （100） surfaces have been taken into account. The structures of reactants and products have been optimized, transition states have been confirmed and activation energies have been calculated. The adsorption energy of reactants and desorption energy of products have been determined. All of these have been employed to confirm the reaction mechanism and the rate determining step ofAlCl disproportionation reaction on the aluminum （100） surfaces.展开更多
The selective synthesis of p-diethylbenzene （p-DEB） by disproportionation of ethylbenzene （EB） in the presence of aromatics like m- and p- xylene isomers has been studied over a pore size regulated HZSM-5 catalyst...The selective synthesis of p-diethylbenzene （p-DEB） by disproportionation of ethylbenzene （EB） in the presence of aromatics like m- and p- xylene isomers has been studied over a pore size regulated HZSM-5 catalyst. The industrial feed having different compositions of ethylbenzene and xylene isomers was used for the experimentation. Hence, they were expected to hinder the movement of reactant molecules both on the external surface and within the zeolite channels. It was observed that irrespective of the different feed compositions the concentration of the xylene isomers was intact in the product. There is no other byproducts formation like para-ethylmethyl benzene. The effects of varying the concentration of aromatic compounds in the feed on ethylbenzene conversion and product distribution over the parent and modified H-ZSM-5 catalyst have been discussed. Ethylbenzene disproportionation reaction follows the pseudo first order reaction with an activation energy of 8.6 kcal/mol.展开更多
A new method of synthesizing single-component molecular conductor [Ni(dmit)2] by the reaction 2(Me4N)[Ni(dmit)2]2 [Ni(dmit)2] + (Me4N)[Ni(dmit)2] is reported. [Ni(dmit)2] exhibits a semiconductive behavior above 167...A new method of synthesizing single-component molecular conductor [Ni(dmit)2] by the reaction 2(Me4N)[Ni(dmit)2]2 [Ni(dmit)2] + (Me4N)[Ni(dmit)2] is reported. [Ni(dmit)2] exhibits a semiconductive behavior above 167 K, while from 167 K down to the measuring limit of 60 K, it exhibits metallic conductivity.展开更多
The disproportionated phases of Nd Hx, Fe2B,and a-Fe from Nd2Fe14B were applied to prepare Nd Fe B magnets by two different routes. The results show that the route of annealing in horizontal vacuum sintering furnace c...The disproportionated phases of Nd Hx, Fe2B,and a-Fe from Nd2Fe14B were applied to prepare Nd Fe B magnets by two different routes. The results show that the route of annealing in horizontal vacuum sintering furnace cannot reach the purpose of complete recombination after the hot pressing and hot deformation process due to the lack of dehydrogenation channel. The route of applying low pressure of 4–25 MPa on the as-disproportionated green compact during the desorption recombination process in situ hot deformation in a spark plasma sintering（SPS）system can obtain completely recombined Nd Fe B magnet with good anisotropy and magnetic properties. The maximum magnetic properties,（BH）max= 201 kJ m^-3,Br= 1.142 T and Hcj= 469 k A m^-1, are obtained after being treated for 15 min at 750 ℃ under low pressure.展开更多
Transformation-temperature-hydrogen pressure phase diagram was constructed for a Nd15Fe79B6 alloy in order to estimate appropriate conditions for hydrogenation, disproportionation, desorption and recombination reacti...Transformation-temperature-hydrogen pressure phase diagram was constructed for a Nd15Fe79B6 alloy in order to estimate appropriate conditions for hydrogenation, disproportionation, desorption and recombination reaction （the HDDR）. Optimised recom- bination time （the highest coercivity） was found to be 10 rain. for 5 g samples processed at 740 ℃. Several HDDR processes were carried out at 30 kPa of hydrogen pressure at various temperatures. No correlation between magnetic propertiec and a direction of measurement was observed for the samples processed at 740 ℃. Remanence anisotropy was induced along an alignment direction when the temperature of the HDDR process was increased up to 800 ℃ and 850℃ for 〈100 gm and 100-160 p.m particles, respec- tively. Simultaneously, a small drop in coercivity was observed in the direction of alignment for 〈100 pm particles, but no for 100-160 grn particles. Furthermore, probably an ordered phase was found by TEM microstructure analysis in the bulk sample dis- proportionated at 850 ℃ under 150 kPa of hydrogen. Grains with antiphase domains were observed and corresponding electron dif- fraction patterns were resolved, likely indicating superlattice structures.展开更多
BACKGROUND Congenital fiber-type disproportion(CFTD)is a form of congenital myopathy.CFTD is rare,especially when presenting in patients with critical illnesses.Here,we report a case of CFTD presenting with type II re...BACKGROUND Congenital fiber-type disproportion(CFTD)is a form of congenital myopathy.CFTD is rare,especially when presenting in patients with critical illnesses.Here,we report a case of CFTD presenting with type II respiratory failure after delivery and provide a review of the literature on CFTD.CASE SUMMARY A 30-year-old woman was admitted to the obstetrics department of our hospital with premature rupture of the fetal membrane and with 7 h of regular contractions.After delivery,the patient experienced a refractory type II respiratory failure.Physical examination along with diagnostic procedures such as electromyography and biopsy confirmed CFTD.Use of invasive ventilator followed by intermittent use of noninvasive ventilator attenuated her symptoms.The patient recovered after ventilator-assisted respiration and was weaned off the noninvasive ventilator on the seventh day postpartum.CONCLUSION Congenital myopathy should be considered a differential diagnosis for type II respiratory failures that cannot be attributed to other diseases.展开更多
The paper refers to disproportionation of HIO and NaIO in aqueous media, in static and dynamic systems. The results of calculations, realized according to GATES/GEB principles, with use of an iterative computer progra...The paper refers to disproportionation of HIO and NaIO in aqueous media, in static and dynamic systems. The results of calculations, realized according to GATES/GEB principles, with use of an iterative computer program, are presented graphically. An example of the computer program with all physicochemical knowledge involved in the related algorithm is attached herewith.展开更多
This paper evaluates the thermodynamic possibility of coalbed methane formation as a result of direct reaction of coal and water during the process of hydrolytic disproportionation of carbon(HDC).Some examples of expe...This paper evaluates the thermodynamic possibility of coalbed methane formation as a result of direct reaction of coal and water during the process of hydrolytic disproportionation of carbon(HDC).Some examples of experimental and natural evidences of HDC are discussed.展开更多
Mechanically activated disproportionation of Nd 12 Fe 82 B 6 alloy by ball milling in hydrogen atmosphere was experimentally investigated. The aspects of thermodynamics and kinetics for the mechanically activated disp...Mechanically activated disproportionation of Nd 12 Fe 82 B 6 alloy by ball milling in hydrogen atmosphere was experimentally investigated. The aspects of thermodynamics and kinetics for the mechanically activated disproportionation of the NdFeB alloy were discussed. Both the evolution of the disproportionation reaction and the corresponding microstructure change of the alloy during milling were characterized by X ray diffraction (XRD) analysis. The results show that the matrix phase Nd 2Fe 14 B of the as cast Nd 12 Fe 82 B 6 alloy can be disproportionated into a mixture of Nd hydride (H 5Nd 2), FeB/Fe 2B, and α Fe, by ball milling under hydrogen pressure of 0.2 MPa. The as disproportionated phases are of the size about 20 nm, suggesting that ball milling in hydrogen is an effective route for low temperature disproportionation processing of the NdFeB alloy to ensure a full nano structured as disproportionated microstructure. This is the basis for synthesizing Nd 2Fe 14 B/ α Fe nano composites with magnetic exchange coupling effect by subsequent desorption recombination processing.展开更多
Tacrolimus(Tac)is a cornerstone immunosuppressant in the treatment regimens for organ transplant recipients.However,its extensive clinical use has brought attention to its associated drug safety concerns.Recent case r...Tacrolimus(Tac)is a cornerstone immunosuppressant in the treatment regimens for organ transplant recipients.However,its extensive clinical use has brought attention to its associated drug safety concerns.Recent case reports highlighting Tac-induced gastrointestinal ulcers have prompted further investigation.In the present study,we analyzed Tac-associated adverse events using data from the U.S.Food and Drug Administration Adverse Event Reporting System(FAERS)to identify potential adverse event signals.Adverse event reports were collected up to the third quarter(Q3)of 2023,revealing 339 cases of Tac-related gastrointestinal ulcers.A disproportionality analysis was conducted utilizing the Bayesian confidence propagation neural network of information component(IC)and reporting odds ratio(ROR)methods.All statistical analyses were performed using R version 3.6.1.The findings demonstrated a significant signal for gastrointestinal ulcers associated with Tac use,with a ROR1 of 1.87(95%CI:1.68-2.08)and an IC1 of 0.89(95%CI:0.73-1.05)when compared to all other drugs.When compared specifically to cyclosporine,Tac also showed a significant signal(ROR2=1.55,95%CI:1.28-1.86;IC2=0.24,95%CI:0.04-0.44).Further analysis identified age,male gender,and European descent as risk factors for mortality outcomes in patients with Tac-associated gastrointestinal ulcers.These findings highlighted the critical need for clinicians to strengthen the monitoring and early detection of gastrointestinal ulcers in patients undergoing Tac therapy.Enhanced vigilance in this regard is essential to optimize the management and care of transplant patients.展开更多
文摘Methyl methoxyacetate(MMAc)and methyl formate(MF)can be produced directly by heterogeneous zeolite-catalyzed carbonylation and disproportionation of dimethoxymethane(DMM),with near 100%selectivity for each process.Despite continuous research efforts,the insight into the reaction mechanism and kinetics theory are still in their nascent stage.In this study,ZEO-1 material,a zeolite with up to now the largest cages comprising 16×16-MRs,16×12-MRs,and 12×12-MRs,was explored for DMM carbonylation and disproportionation reactions.The rate of MMAc formation based on accessible Brönsted acid sites is 2.5 times higher for ZEO-1(Si/Al=21)relative to the previously investigated FAU(Si/Al=15),indicating the positive effect of spatial separation of active sites in ZEO-1 on catalytic activity.A higher MF formation rate is also observed over ZEO-1 with lower activation energy(79.94 vs.95.19 kJ/mol)compared with FAU(Si/Al=30).Two types of active sites are proposed within ZEO-1 zeolite:Site 1 located in large cages formed by 16×16-MRs and 16×12-MRs,which is active predominantly for MMAc formation,and Site 2 located in smaller cages for methyl formate/dimethyl ether formation.Kinetics investigation of DMM carbonylation over ZEO-1 exhibit a first-order dependence on CO partial pressure and a slightly inverse-order dependence on DMM partial pressure.The DMM disproportionation is nearly first-order dependence on DMM partial pressure,while it reveals a strongly inverse dependence with increasing CO partial pressure.Furthermore,ZEO-1 exhibits good catalytic stability,and almost no deactivation is observed during the more than 70 h test with high carbonylation selectivity of above 89%,due to the well-enhanced diffusion property demonstrated by intelligent-gravimetric analysis.
基金Project(51264023)supported by the National Natural Science Foundation of ChinaProject(KKSY201207016)supported by Yunnan Provincial Science and Technology Department,China
文摘The extraction conditions of aluminum by the disproportionation process of A1C1 in vacuum were investigated using alumina and graphite as raw materials, including reaction temperature, pre-reaction and condenser structure. The results show that the extent of the reaction between alumina and carbon increases with increasing reaction temperature at 1643-1843 K; however, the extraction rate of aluminum increases firstly, and reaches the highest at 1743 K, and then decreases with rise in reaction temperature. The pre-reaction of alumina and carbon increases the extraction rate of aluminum. The impurities C, AlaC3 and A1203 in the aluminum product are reduced with reducing the contact surface of the aluminum with CO and with decreasing the condensation temperature, depending on the structure of the condenser.
基金Project(51364020)supported by the National Natural Science Foundation of China
文摘The formation conditions of C, Al4C3 and Al2O3 in the Al Cl disproportionation process in vacuum to produce aluminum was investigated by thermodynamics analysis. It is demonstrated that the required temperatures for the reactions to form these impurities, the disproportionation of CO and the reactions of metallic aluminum with CO, decrease with decreasing pressure. The lg pCO-1/T diagram of metallic aluminum-CO system agrees with the experimental results, indicating that the reaction rate is very high and this system in vacuum is approximately in equilibrium; therefore, the equilibrium diagram can be used to predict the possible reactions in this system in vacuum.
基金supported financially by the National Natural Science Foundation of China(Nos.51671204 and 51501205).
文摘A high-efficiency method is developed to in-situ synthesize nanocrystalline TiC powders,nanorods,and nanosheets by using equimolar ratio of Ti powder and acetylene black,multiwalled carbon nanotubes(MWCNTs),and graphene,respectively,as precursor in eutectic Na Cl-KCl molten salt at 800–900℃for 2–3 h.Higher temperature and longer duration are more beneficial for TiC preparation.In addition,mechanism of TiC formation was investigated by linear scan voltammetry.Results indicate that nanocrystalline TiC is in-situ synthesized by reaction between Ti atoms,which come from disproportionation reaction of Ti(Ⅱ)species in the molten salt,and C atoms on the surface of carbon sources.
基金Supported by the Key Natural Science Foundation for Universities of Jiangsu Province（06KJA53012） the National Natural Science Foundation of China（20776069 20976084）
文摘Shape-selective catalysts for the disproportionation of toluene were prepared by the modification of the cylinder-shaped ZSM-5 zeolite extrudates with chemical liquid deposition with TEOS （tetraethyl orthosilicate）.Various parameters for preparing catalysts were changed to investigate the suitable conditions.The resulting cata-lysts were tested in a pressured fixed bed reactor and characterized by SEM （scanning electron microscopy）.The conversion of toluene and para-xylene selectivity were influenced remarkably by the n（SiO2）/n（Al2O3） ratio of ZSM-5 zeolite,the type and amount of deposition agent,acid and solvent used,and the time and cycle of deposition treatment.TEOS was proved to be a more efficient agent than the conventional polysiloxanes when the deposition amount was low.The catalyst prepared at the suitable conditions exhibited a high para-xylene selectivity of 91.1% with considerable high conversion of 25.6%.SEM analyses confirmed the formation of a layer of amorphous silica on the external surface of ZSM-5 zeolie crystals,which was responsible for the highly enhanced shape-selectivity.
基金Project (u0837604) supported by the Joint Funds of the National Natural Science Foundation of China and Yunnan Province
文摘The carbothermal reduction-chlorination-disproportionation of alumina in vacuum was investigated by XRD and thermodynamic analysis. The experiments on alumina and graphite at 1643-1843 K in vacuum were carried out. The results demonstrate that AlCl3（g） reacts with Al2O（g） or Al（g） generated from the carbothermal reduction of alumina to form AlCl（g）, and the AlCl（g） disproportionates to aluminum and AlCl3（g） at a lower temperature and the reaction rate of AlCl（g） reaches 90% at 980 K and 100 Pa. The aluminum can absorb CO to catalyze its disproportionation to C and CO2, and react backward with CO to form Al4C3, Al2O3, C and CO2, resulting in the aluminum product containing C, Al4C3 and Al2O3. The impurities in the aluminum product decrease as the AlCl（g） disproportionation temperature decreases. AlCl3 condenses at a temperature approximated to the room temperature.
基金Supported by the National＇Creative Research Groups Science Foundation of China （No.60421002） and priority supported financially by ＂the New Century 151 Talent Project＂ of Zhejiang Province.
文摘A new kinetic model for commercial unit of toluene disproportionation and C9-armatiocs transalkylation is developed based on the reported reaction scheme.A time based catalyst deactivation function taking weight hourly space velocity(WHSV)into account is incorporated into the model,which reasonably accounts for the loss in activity because of coke deposition on the surface of catalyst during long-term operation.The kinetic parameters are benchmarked with several sets of balanced plant data and estimated by the differential variable metric optimiza- tion method.Sets of plant data at different operating conditions are applied to make sure validation of the model and the results show a good agreement between the model predictions and plant observations.The simulation analysis of key variables such as temperature and WHSV affecting process performance is discussed in detail,giv- ing the guidance to select suitable operating conditions.
基金Supported by the Joint Funds of the National Natural Science Foundation of China(No.u0837604) the Funds for Applied Basic Researches of Yunnan Province(No.2010CD022)
文摘The surface disproportionation reaction mechanism of aluminum subchloride on the aluminum （100） surfaces has been investigated by the plane-wave density functional theory （DFT）. Three kinds of possible reaction mechanism of AlCl disproportionation reaction on the aluminum （100） surfaces have been taken into account. The structures of reactants and products have been optimized, transition states have been confirmed and activation energies have been calculated. The adsorption energy of reactants and desorption energy of products have been determined. All of these have been employed to confirm the reaction mechanism and the rate determining step ofAlCl disproportionation reaction on the aluminum （100） surfaces.
文摘The selective synthesis of p-diethylbenzene （p-DEB） by disproportionation of ethylbenzene （EB） in the presence of aromatics like m- and p- xylene isomers has been studied over a pore size regulated HZSM-5 catalyst. The industrial feed having different compositions of ethylbenzene and xylene isomers was used for the experimentation. Hence, they were expected to hinder the movement of reactant molecules both on the external surface and within the zeolite channels. It was observed that irrespective of the different feed compositions the concentration of the xylene isomers was intact in the product. There is no other byproducts formation like para-ethylmethyl benzene. The effects of varying the concentration of aromatic compounds in the feed on ethylbenzene conversion and product distribution over the parent and modified H-ZSM-5 catalyst have been discussed. Ethylbenzene disproportionation reaction follows the pseudo first order reaction with an activation energy of 8.6 kcal/mol.
基金supported by the National Natural Science Foundation of China(No.20172034)Foundation for Univemity Key Teacher by Ministry of Educationthe grant for the State Key Program of China.
文摘A new method of synthesizing single-component molecular conductor [Ni(dmit)2] by the reaction 2(Me4N)[Ni(dmit)2]2 [Ni(dmit)2] + (Me4N)[Ni(dmit)2] is reported. [Ni(dmit)2] exhibits a semiconductive behavior above 167 K, while from 167 K down to the measuring limit of 60 K, it exhibits metallic conductivity.
基金financially supported by the National Natural Science Foundation of China (No. 51171122)
文摘The disproportionated phases of Nd Hx, Fe2B,and a-Fe from Nd2Fe14B were applied to prepare Nd Fe B magnets by two different routes. The results show that the route of annealing in horizontal vacuum sintering furnace cannot reach the purpose of complete recombination after the hot pressing and hot deformation process due to the lack of dehydrogenation channel. The route of applying low pressure of 4–25 MPa on the as-disproportionated green compact during the desorption recombination process in situ hot deformation in a spark plasma sintering（SPS）system can obtain completely recombined Nd Fe B magnet with good anisotropy and magnetic properties. The maximum magnetic properties,（BH）max= 201 kJ m^-3,Br= 1.142 T and Hcj= 469 k A m^-1, are obtained after being treated for 15 min at 750 ℃ under low pressure.
基金Project supported by the National Centre for Research and Development(INNOTECH-K2/IN2/18/181960/NCBR/13)
文摘Transformation-temperature-hydrogen pressure phase diagram was constructed for a Nd15Fe79B6 alloy in order to estimate appropriate conditions for hydrogenation, disproportionation, desorption and recombination reaction （the HDDR）. Optimised recom- bination time （the highest coercivity） was found to be 10 rain. for 5 g samples processed at 740 ℃. Several HDDR processes were carried out at 30 kPa of hydrogen pressure at various temperatures. No correlation between magnetic propertiec and a direction of measurement was observed for the samples processed at 740 ℃. Remanence anisotropy was induced along an alignment direction when the temperature of the HDDR process was increased up to 800 ℃ and 850℃ for 〈100 gm and 100-160 p.m particles, respec- tively. Simultaneously, a small drop in coercivity was observed in the direction of alignment for 〈100 pm particles, but no for 100-160 grn particles. Furthermore, probably an ordered phase was found by TEM microstructure analysis in the bulk sample dis- proportionated at 850 ℃ under 150 kPa of hydrogen. Grains with antiphase domains were observed and corresponding electron dif- fraction patterns were resolved, likely indicating superlattice structures.
文摘BACKGROUND Congenital fiber-type disproportion(CFTD)is a form of congenital myopathy.CFTD is rare,especially when presenting in patients with critical illnesses.Here,we report a case of CFTD presenting with type II respiratory failure after delivery and provide a review of the literature on CFTD.CASE SUMMARY A 30-year-old woman was admitted to the obstetrics department of our hospital with premature rupture of the fetal membrane and with 7 h of regular contractions.After delivery,the patient experienced a refractory type II respiratory failure.Physical examination along with diagnostic procedures such as electromyography and biopsy confirmed CFTD.Use of invasive ventilator followed by intermittent use of noninvasive ventilator attenuated her symptoms.The patient recovered after ventilator-assisted respiration and was weaned off the noninvasive ventilator on the seventh day postpartum.CONCLUSION Congenital myopathy should be considered a differential diagnosis for type II respiratory failures that cannot be attributed to other diseases.
文摘The paper refers to disproportionation of HIO and NaIO in aqueous media, in static and dynamic systems. The results of calculations, realized according to GATES/GEB principles, with use of an iterative computer program, are presented graphically. An example of the computer program with all physicochemical knowledge involved in the related algorithm is attached herewith.
文摘This paper evaluates the thermodynamic possibility of coalbed methane formation as a result of direct reaction of coal and water during the process of hydrolytic disproportionation of carbon(HDC).Some examples of experimental and natural evidences of HDC are discussed.
文摘Mechanically activated disproportionation of Nd 12 Fe 82 B 6 alloy by ball milling in hydrogen atmosphere was experimentally investigated. The aspects of thermodynamics and kinetics for the mechanically activated disproportionation of the NdFeB alloy were discussed. Both the evolution of the disproportionation reaction and the corresponding microstructure change of the alloy during milling were characterized by X ray diffraction (XRD) analysis. The results show that the matrix phase Nd 2Fe 14 B of the as cast Nd 12 Fe 82 B 6 alloy can be disproportionated into a mixture of Nd hydride (H 5Nd 2), FeB/Fe 2B, and α Fe, by ball milling under hydrogen pressure of 0.2 MPa. The as disproportionated phases are of the size about 20 nm, suggesting that ball milling in hydrogen is an effective route for low temperature disproportionation processing of the NdFeB alloy to ensure a full nano structured as disproportionated microstructure. This is the basis for synthesizing Nd 2Fe 14 B/ α Fe nano composites with magnetic exchange coupling effect by subsequent desorption recombination processing.
文摘Tacrolimus(Tac)is a cornerstone immunosuppressant in the treatment regimens for organ transplant recipients.However,its extensive clinical use has brought attention to its associated drug safety concerns.Recent case reports highlighting Tac-induced gastrointestinal ulcers have prompted further investigation.In the present study,we analyzed Tac-associated adverse events using data from the U.S.Food and Drug Administration Adverse Event Reporting System(FAERS)to identify potential adverse event signals.Adverse event reports were collected up to the third quarter(Q3)of 2023,revealing 339 cases of Tac-related gastrointestinal ulcers.A disproportionality analysis was conducted utilizing the Bayesian confidence propagation neural network of information component(IC)and reporting odds ratio(ROR)methods.All statistical analyses were performed using R version 3.6.1.The findings demonstrated a significant signal for gastrointestinal ulcers associated with Tac use,with a ROR1 of 1.87(95%CI:1.68-2.08)and an IC1 of 0.89(95%CI:0.73-1.05)when compared to all other drugs.When compared specifically to cyclosporine,Tac also showed a significant signal(ROR2=1.55,95%CI:1.28-1.86;IC2=0.24,95%CI:0.04-0.44).Further analysis identified age,male gender,and European descent as risk factors for mortality outcomes in patients with Tac-associated gastrointestinal ulcers.These findings highlighted the critical need for clinicians to strengthen the monitoring and early detection of gastrointestinal ulcers in patients undergoing Tac therapy.Enhanced vigilance in this regard is essential to optimize the management and care of transplant patients.
