Metal-to-insulator transitions (MITs),which are achieved in 3d-band correlated transitional metal oxides,trigger abrupt variations in electrical,optical,and/or magnetic properties beyond those of conventional semicond...Metal-to-insulator transitions (MITs),which are achieved in 3d-band correlated transitional metal oxides,trigger abrupt variations in electrical,optical,and/or magnetic properties beyond those of conventional semiconductors.Among such material families,iron(Fe:3d^(6)4s^(2))-containing oxides pique interest owing to their widely tunable MIT properties,which are associated with the various valence states of Fe.Their potential electronic applications also show promise,given the large abundance of Fe on Earth.Representative MIT properties triggered by critical temperature (TMIT) were reported for ReFe_(2)O_(4)(Fe^(2.5+)),ReBaFe_(2)O_(5)(Fe^(2.5+)),Fe_(3)O_(4)(Fe^(2.67+)),Re_(1/3)Sr_(2/3)FeO_(3)(Fe^(3.67+)),Re Cu_(3)Fe_(4)O_(12)(Fe^(3.75+)),and Ca_(1-x)Sr_(x)FeO_(3)(Fe^(4+))(where Re represents rare-earth elements).The common feature of MITs of these Fe-containing oxides is that they are usually accompanied by charge ordering transitions or disproportionation associated with the valence states of Fe.Herein,we review the material family of Fe-containing MIT oxides,their MIT functionalities,and their respective mechanisms.From the perspective of potentially correlated electronic applications,the tunability of the TMITand its resultant resistive change in Fe-containing oxides are summarized and further compared with those of other materials exhibiting MIT functionality.In particular,we highlight the abrupt MIT and wide tunability of TMITof Fe-containing quadruple perovskites,such as Re Cu3Fe4O12.However,their effective material synthesis still needs to be further explored to cater to potential applications.展开更多
Diphenyl carbonate(DPC)is one of the versatile carbonates,and is often used for the production of polycarbonates.In recent years,the catalytic synthesis of DPC has become an important topic but the development of a hi...Diphenyl carbonate(DPC)is one of the versatile carbonates,and is often used for the production of polycarbonates.In recent years,the catalytic synthesis of DPC has become an important topic but the development of a highly active metal-free catalyst is a great challenge.Herein,a series of ionic liquids-SBA-15 hybrid catalysts with different functional groups have been developed for the synthesis of DPC under solventfree condition,which are effective and clean instead of the metal-containing catalysts.It is found that in the presence of[SBA-15-IL-OH]Br catalyst,methyl phenyl carbonate(MPC)conversion of 80.5%along with 99.6%DPC selectivity is achieved,the TOF value is thrice higher than the best value reported by using transition metal-based catalysts.Moreover,the catalyst displays remarkable stability and recyclability.This work provides a new idea to design and prepare eco-friendly catalysts in a broad range of applications for the green synthesis of carbonates.展开更多
Caesarean section (CS) is a surgical procedure performed to remove a fetus from the mother’s uterus through an incision on the abdominal wall, then on the uterine wall. The indications of CS vary not only between cou...Caesarean section (CS) is a surgical procedure performed to remove a fetus from the mother’s uterus through an incision on the abdominal wall, then on the uterine wall. The indications of CS vary not only between countries, but also from one hospital to another and from one team to another within the same hospital. Despite advances in asepsis and anesthesia/resuscitation technics, there are still complications of varying severity inherent to the gravid-puerperal state on one hand and the technics used on the other, irrespective of the operative indication. Thus, the present study was carried out with the objectives of determining the prevalence, identifying the indications, and evaluating the morbidity linked to caesarean sections in our environment. Cameroon has also set up a health voucher program in its northern region, aimed at reducing maternal and fetus morbidity and mortality. The program aims to improve financial access in antenatal care and deliveries, including caesarean sections, in this low-income region of the country. We conducted a descriptive cross-sectional study with retrospective data collection, from February 1, 2022, to May 31, 2022. We included all women who gave birth by caesarean section. In our study series, out of 905 parturient admissions into the Department of Obstetrics and Gynecology, 226 were caesarian cases. The overall frequency of CS during our study period was 25%. Fetal indications were dominated by cephalopelvic disproportion and non-reassuring fetal heart in 17.3% and 13.7% of cases respectively. Intraoperative complications were dominated by hemorrhage (15.5%). In our study, we noted an 11.1% of prevalence perinatal mortality. Cameroon is a low-income country with limited financial resources, especially in the Northern region. The health voucher program has improved financial access to caesarean sections for parturient in northern Cameroon, and consequently to emergency obstetric and neonatal care.展开更多
The Annular Crossed Cable-Truss Structure(ACCTS) is a new type of Tensile Spatial Structure with a configuration suitable to cover large-span stadiums. Its configuration has potential to perform well in resisting di...The Annular Crossed Cable-Truss Structure(ACCTS) is a new type of Tensile Spatial Structure with a configuration suitable to cover large-span stadiums. Its configuration has potential to perform well in resisting disproportionate collapse. However, its disproportionate collapse resistance hasn't yet been analyzed in depth. In this study, numerical and experimental research was carried out to investigate the performance of ACCTS under cable rupture. The numerical analysis was done for ten cable-rupture plans using LS-DYNA(explicit method) and the experimental test on an ACCTS with a diameter of 17.15 m was performed for three cable-rupture plans. It is concluded that, while deflections increase with the number of removed cables, an ACCTS does not undergo a disproportionate collapse and it provides a promising structural concept for tensile spatial structures.展开更多
The thermal dissolved sulfuration technology is brought forward and performed based on the characteristic of low grade lead-zinc oxide ore in lanpin. Using sulfur as the sulphidizing agent in the experiment, the oxide...The thermal dissolved sulfuration technology is brought forward and performed based on the characteristic of low grade lead-zinc oxide ore in lanpin. Using sulfur as the sulphidizing agent in the experiment, the oxides in the sandstone and ignimbrite are changed into sulfides. The disproportionation reaction of sulfur in a solution is confirmed as 4S+3H2O=2S^2-+S2O3^2--+6H^+. The dynamics process is studied and the first-order reaction rate equation -1n(1-a)=ktt is obtained. The effects of the reactive products, stirring speed, dosage of sulfuration agent, value of pH and sulphidizing temperature on the sulfuration of oxide ore are investigated. The results indicate that the reactive apparent activation energy is 100.8 kJ/mol and the sulfuration ratio of lead-zinc oxide ore reaches 60% under the conditions of pH 5.9-7.5, the sulfuration temperature of 130 ℃, sulfuration time of 180 min and the stirring speed of 800 r/min.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 ligand, 2-(2-hydroxyphenyl)-5,6-dichlorobenzimidazole, H2pbmCl2(1), and a novel MnIII complex, [MnIII(HpbmCl2)(pbmCl2)(DMF)2](2),(DMF = N,N-dimethylformamide), have been synthesized and characteriz...A new ligand, 2-(2-hydroxyphenyl)-5,6-dichlorobenzimidazole, H2pbmCl2(1), and a novel MnIII complex, [MnIII(HpbmCl2)(pbmCl2)(DMF)2](2),(DMF = N,N-dimethylformamide), have been synthesized and characterized. The crystal of compound 1(C13H8Cl2N2O, Mr = 279.12) belongs to the monoclinic system, space group P21 with a = 3.770(5), b = 25.20(3), c = 5.865(7) A, = 92.727(17)o, V = 556.6(12) A3, Z = 2, Dc = 1.665 g/cm^3, S = 1.137, μ= 0.568 mm^-1, F(000) = 284, the final R = 0.0876 and wR = 0.2334 for 1848 independent reflections. The molecule is planar due to the presence of a strong intramolecular hydrogen bond between O–H group of phenol and N atom of imidazole. H2pbmCl2(1) molecules are arranged into a one-dimensional linear chain through intermolecular hydrogen bonds(N–H…O and C–H…Cl). The crystal of complex 2(C32H27Cl4MnN6O4, Mr = 756.34) belongs to the monoclinic system, space group P21/c with a = 19.043(10), b = 10.808(5), c = 18.704(11)A, β= 115.540(6)°, V = 3473(3) A3, Z = 4, Dc = 1.446 g/cm^3, S = 1.3, μ = 0.733 mm-1, F(000) = 1544, the final R = 0.1219 and wR = 0.2681 for 7811 independent reflections. The Mn ion adopts a distorted octahedral geometry coordinated by two deprotonated H2pbmCl2 ligands and two DMF molecules. The [MnIII(HpbmCl2)(pbmCl2)(DMF)2] molecules are arranged into a three-dimensional structure through hydrogen bonds(N–H…N, C–H…N and C–H…Cl) and weak π···πinteractions. The activity measurements suggest that complex 2 is able to serve as a catalyst for H2O2 disproportionation reaction to form O2 in neutral water solution.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
Development of active iron based water oxidation for designing an ideal artificial photosynthesis devices operating under benign neutral pH is highly demanded. We investigated the electrocatalytic activity of Ruddlesd...Development of active iron based water oxidation for designing an ideal artificial photosynthesis devices operating under benign neutral pH is highly demanded. We investigated the electrocatalytic activity of Ruddlesden-Pop-per-type strontium ferrite (Sr3Fe2O7) toward the oxygen evolution reaction (OER). Owing to the temperature-dependent efficiency of the charge disproportionation of Fe4+, the OER activity of Sr3Fe2O7 varied with the temperature, and the onset potential for the OER at a neutral pH underwent a negative shift of approximately 200 mV by increasing the temperature for the stabilization of Fe4+. When metal substitution was made to Sr3Fe2O7 for stabilizing Fe4+ at room temperature, the temperature dependence of the OER activity disappeared and the OER was driven at a small overpotential without increasing the temperature, indicating that the stabilization of Fe4+ is substantially important for achieving high OER activity.展开更多
A carbon-supported Ru catalyst, Ru/BP2000, is able to simultaneously convert cellobiose into sorbitol and gluconic acid. This reaction occurs as the result of hydrolytic disproportionation in water at 393 K under an A...A carbon-supported Ru catalyst, Ru/BP2000, is able to simultaneously convert cellobiose into sorbitol and gluconic acid. This reaction occurs as the result of hydrolytic disproportionation in water at 393 K under an Ar atmosphere, without bases or sacrificial reagents. In-situ XANES measurements suggest that the active Ru species involved is composed of partially oxidized Ru metal.展开更多
The influence of the RE-rich phase distribution in the precursor alloys on the anisotropy of the hydrogenation disproportionation desorption recombination(HDDR) processed powders is investigated. The homogenized ing...The influence of the RE-rich phase distribution in the precursor alloys on the anisotropy of the hydrogenation disproportionation desorption recombination(HDDR) processed powders is investigated. The homogenized ingot alloy and the as-cast strip casting(SC) alloy with a uniform RE-rich grain boundary phase lead to high anisotropy of the refined powders,acquiring degrees of alignment(DOA) of 0.62 and 0.54, respectively. The RE-rich phase aggregation results in a deteriorated DOA of the powders due to the drastic disproportionation rate, while a thin and uniform RE-rich phase distribution is beneficial for DOA. A reaction model of the initial particle microstructure is proposed for optimizing the HDDR powder anisotropy.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
In the solvothermal condition, a Pd(II) complex with a in situ synthesis ligand, [Pd(2,2’-bipy)2(CN)2] (1) was obtained and characterized by elemental analysis, IR, UV, TG, and powder X-ray analysis. The single cryst...In the solvothermal condition, a Pd(II) complex with a in situ synthesis ligand, [Pd(2,2’-bipy)2(CN)2] (1) was obtained and characterized by elemental analysis, IR, UV, TG, and powder X-ray analysis. The single crystal X-ray analysis showed that the title complex is different from the reported 2,2’-bipyridyl-dicyanopalladium(II) (2) in crystal system and structural parameters. The catalytic investigation for the reactions of the disproportionation of hydrogen peroxide and oxidation of sulfide showed that the complex 1 is an active homogeneous catalyst in the presence of imidazole and 2-sulfobenzoic acid, respectively.展开更多
In the equation U = I – A for the Mott energy, the electron-hole interaction of the successor state is missing. Adding the attractive term, the energy for disproportionation (Hubbard U), may adopt any sign. The missi...In the equation U = I – A for the Mott energy, the electron-hole interaction of the successor state is missing. Adding the attractive term, the energy for disproportionation (Hubbard U), may adopt any sign. The missing term is related to the Born effect, the Madelung correction and the Lattice Enthalpy.展开更多
Shipping industry has become more capital intensive, technically more demanding and subject to major global regulatory reforms. As a consequence, the number of African shipping lines has been severely reduced. Interna...Shipping industry has become more capital intensive, technically more demanding and subject to major global regulatory reforms. As a consequence, the number of African shipping lines has been severely reduced. International trade of the WCA countries remains weak, limited to 30% of their Gross Domestic Product (GDP). The goal of this paper is to provide a comprehensive overview of the port and shipping convey management in the WCA region, and of course to describe what has been achieved since then and what still have to be done to better its infrastructures and port community.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
Superlattices in crystals,particularly in perovskite oxides with strong correlation effects,can create new states of matter and produce peculiar physicochemical phenomena.However,the newfangled perovskite superlattice...Superlattices in crystals,particularly in perovskite oxides with strong correlation effects,can create new states of matter and produce peculiar physicochemical phenomena.However,the newfangled perovskite superlattices depend on physical deposition with unit-cell precision.It has been challenging to explore a new suitable chemical method to tailor perovskite superlattices.Herein,we present a new bottomup strategy to precisely prepare atomic-scale oxide superlattices of(LaMnO_(3))_(1)-(La_(1-x-y)Ca_(x)K_(y)MnO_(3))_(2)in a monodispersed perovskite La_(0.66)Ca_(0.29)K_(0.05)MnO_(3)(LCKMO).The special atomic-scale perovskite superlattices are demonstrated using SAED,HAADF-STEM,XRD,and atomic-resolution elemental mapping.Our experiments reveal that the perovskite superlattices can be fabricated under extreme hydrothermal conditions utilizing ultra-high concentrations of KOH.An approximate molten salt system in the hydrothermal process can induce the disproportionation reaction of MnO_(2)solids,which is vital to the growth of ordered perovskite superlattices.This work not only clarifies the hydrothermal growth process of perovskite oxides in extreme conditions,but also proposes a novel engineering route toward perovskite superlattices.展开更多
TiC coating on 316L stainless steel surface is prepared by molten salt disproportionation reaction by using carbon layer converted from organic carbon solution as carbon source.The Raman and morphology characterizatio...TiC coating on 316L stainless steel surface is prepared by molten salt disproportionation reaction by using carbon layer converted from organic carbon solution as carbon source.The Raman and morphology characterizations show that the carbon layer and TiC coating are successfully prepared on the surface of 316L stainless steel,the prepared carbon layer and 316L matrix have good adhesion,and the prepared TiC coating is smooth and dense.In the simulated cathodic environment of the proton exchange membrane fuel cell,the potentiostatic and potentiodynamic polarization measurements show that the TiC coating has smaller and more stable current density fluctuation than the 316L stainless steel substrate,and the electrochemical impedance test lasting for 275 h still shows better stable corrosion resistance than that of the 316L stainless steel substrate.Finally,in the water contact angle and interface contact resistance tests,the TiC coating consistently maintained better hydrophobicity and lower interface contact resistance values than 316L stainless steel.展开更多
Driven by the minimization of total energy,the multi-domain morphology is preferred in as-grown ferroelectrics to reduce the depolarization and strain energy during the paraelectric to ferroelectric phase transition.H...Driven by the minimization of total energy,the multi-domain morphology is preferred in as-grown ferroelectrics to reduce the depolarization and strain energy during the paraelectric to ferroelectric phase transition.However,the complicated multi-domain is not desirable for certain high-performance ferroelectric electro-optic devices.In this work,we achieve a reproducible and stable large-area monodomain in as-grown bulk ferroelectric single crystal Sn_(2)P_(2)S_(6).The monodomain dominates the entire single crystal,which is attributed to the internal charge carriers from the photoexcited disproportionation reaction of Sn ions.The charge carriers effectively screen the depolarization field and therefore decrease the depolarization energy and facilitate the formation of monodomain.This work offers a potential approach for engineering bulk ferroelectrics with a stable monodomain,which is desirable for the high-performance ferroelectric electro-optic devices.展开更多
基金financially supported by the National Key Research and Development Program of China (No.2021YFA0718900)the National Natural Science Foundation of China (No.62074014)the Xiaomi Scholar project。
文摘Metal-to-insulator transitions (MITs),which are achieved in 3d-band correlated transitional metal oxides,trigger abrupt variations in electrical,optical,and/or magnetic properties beyond those of conventional semiconductors.Among such material families,iron(Fe:3d^(6)4s^(2))-containing oxides pique interest owing to their widely tunable MIT properties,which are associated with the various valence states of Fe.Their potential electronic applications also show promise,given the large abundance of Fe on Earth.Representative MIT properties triggered by critical temperature (TMIT) were reported for ReFe_(2)O_(4)(Fe^(2.5+)),ReBaFe_(2)O_(5)(Fe^(2.5+)),Fe_(3)O_(4)(Fe^(2.67+)),Re_(1/3)Sr_(2/3)FeO_(3)(Fe^(3.67+)),Re Cu_(3)Fe_(4)O_(12)(Fe^(3.75+)),and Ca_(1-x)Sr_(x)FeO_(3)(Fe^(4+))(where Re represents rare-earth elements).The common feature of MITs of these Fe-containing oxides is that they are usually accompanied by charge ordering transitions or disproportionation associated with the valence states of Fe.Herein,we review the material family of Fe-containing MIT oxides,their MIT functionalities,and their respective mechanisms.From the perspective of potentially correlated electronic applications,the tunability of the TMITand its resultant resistive change in Fe-containing oxides are summarized and further compared with those of other materials exhibiting MIT functionality.In particular,we highlight the abrupt MIT and wide tunability of TMITof Fe-containing quadruple perovskites,such as Re Cu3Fe4O12.However,their effective material synthesis still needs to be further explored to cater to potential applications.
基金support from the National Natural Science Foundation of China(No.21808048 and U1704251)Training Plan for University's Young Backbone Teachers of Henan Province(2021GGJS121)+5 种基金Program for Science&Technology Innovation Talents in Universities of Henan Province(23HASTIT014)Postgraduate Education Reform and Quality Improvement Project of Henan Province(YJS2022KC22)Project funded by China Postdoctoral Science Foundation(No.2018M632782)Project funded by Postdoctoral Research Grant in Henan Province(No.001802030)Key Project of Science and Technology Program of Henan Province(No.222102230109,212102310330 and 182102210050)the Science Research Start-up Fund of Henan Institute of Science and Technology(No.2015031).
文摘Diphenyl carbonate(DPC)is one of the versatile carbonates,and is often used for the production of polycarbonates.In recent years,the catalytic synthesis of DPC has become an important topic but the development of a highly active metal-free catalyst is a great challenge.Herein,a series of ionic liquids-SBA-15 hybrid catalysts with different functional groups have been developed for the synthesis of DPC under solventfree condition,which are effective and clean instead of the metal-containing catalysts.It is found that in the presence of[SBA-15-IL-OH]Br catalyst,methyl phenyl carbonate(MPC)conversion of 80.5%along with 99.6%DPC selectivity is achieved,the TOF value is thrice higher than the best value reported by using transition metal-based catalysts.Moreover,the catalyst displays remarkable stability and recyclability.This work provides a new idea to design and prepare eco-friendly catalysts in a broad range of applications for the green synthesis of carbonates.
文摘Caesarean section (CS) is a surgical procedure performed to remove a fetus from the mother’s uterus through an incision on the abdominal wall, then on the uterine wall. The indications of CS vary not only between countries, but also from one hospital to another and from one team to another within the same hospital. Despite advances in asepsis and anesthesia/resuscitation technics, there are still complications of varying severity inherent to the gravid-puerperal state on one hand and the technics used on the other, irrespective of the operative indication. Thus, the present study was carried out with the objectives of determining the prevalence, identifying the indications, and evaluating the morbidity linked to caesarean sections in our environment. Cameroon has also set up a health voucher program in its northern region, aimed at reducing maternal and fetus morbidity and mortality. The program aims to improve financial access in antenatal care and deliveries, including caesarean sections, in this low-income region of the country. We conducted a descriptive cross-sectional study with retrospective data collection, from February 1, 2022, to May 31, 2022. We included all women who gave birth by caesarean section. In our study series, out of 905 parturient admissions into the Department of Obstetrics and Gynecology, 226 were caesarian cases. The overall frequency of CS during our study period was 25%. Fetal indications were dominated by cephalopelvic disproportion and non-reassuring fetal heart in 17.3% and 13.7% of cases respectively. Intraoperative complications were dominated by hemorrhage (15.5%). In our study, we noted an 11.1% of prevalence perinatal mortality. Cameroon is a low-income country with limited financial resources, especially in the Northern region. The health voucher program has improved financial access to caesarean sections for parturient in northern Cameroon, and consequently to emergency obstetric and neonatal care.
基金National Science Foundation of China under Grant Nos.51378031 and 51578019Natural Science Foundation of Beijing under Grant No.8152006Project of Key Laboratory of Urban Security and Disaster Engineering of MOE under Grant No.USDE201401
文摘The Annular Crossed Cable-Truss Structure(ACCTS) is a new type of Tensile Spatial Structure with a configuration suitable to cover large-span stadiums. Its configuration has potential to perform well in resisting disproportionate collapse. However, its disproportionate collapse resistance hasn't yet been analyzed in depth. In this study, numerical and experimental research was carried out to investigate the performance of ACCTS under cable rupture. The numerical analysis was done for ten cable-rupture plans using LS-DYNA(explicit method) and the experimental test on an ACCTS with a diameter of 17.15 m was performed for three cable-rupture plans. It is concluded that, while deflections increase with the number of removed cables, an ACCTS does not undergo a disproportionate collapse and it provides a promising structural concept for tensile spatial structures.
基金supported by Cooperated Project of Academy and College Yunnan province(2003CBALA02P023)
文摘The thermal dissolved sulfuration technology is brought forward and performed based on the characteristic of low grade lead-zinc oxide ore in lanpin. Using sulfur as the sulphidizing agent in the experiment, the oxides in the sandstone and ignimbrite are changed into sulfides. The disproportionation reaction of sulfur in a solution is confirmed as 4S+3H2O=2S^2-+S2O3^2--+6H^+. The dynamics process is studied and the first-order reaction rate equation -1n(1-a)=ktt is obtained. The effects of the reactive products, stirring speed, dosage of sulfuration agent, value of pH and sulphidizing temperature on the sulfuration of oxide ore are investigated. The results indicate that the reactive apparent activation energy is 100.8 kJ/mol and the sulfuration ratio of lead-zinc oxide ore reaches 60% under the conditions of pH 5.9-7.5, the sulfuration temperature of 130 ℃, sulfuration time of 180 min and the stirring speed of 800 r/min.
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.20973186 and 31070216)
文摘A new ligand, 2-(2-hydroxyphenyl)-5,6-dichlorobenzimidazole, H2pbmCl2(1), and a novel MnIII complex, [MnIII(HpbmCl2)(pbmCl2)(DMF)2](2),(DMF = N,N-dimethylformamide), have been synthesized and characterized. The crystal of compound 1(C13H8Cl2N2O, Mr = 279.12) belongs to the monoclinic system, space group P21 with a = 3.770(5), b = 25.20(3), c = 5.865(7) A, = 92.727(17)o, V = 556.6(12) A3, Z = 2, Dc = 1.665 g/cm^3, S = 1.137, μ= 0.568 mm^-1, F(000) = 284, the final R = 0.0876 and wR = 0.2334 for 1848 independent reflections. The molecule is planar due to the presence of a strong intramolecular hydrogen bond between O–H group of phenol and N atom of imidazole. H2pbmCl2(1) molecules are arranged into a one-dimensional linear chain through intermolecular hydrogen bonds(N–H…O and C–H…Cl). The crystal of complex 2(C32H27Cl4MnN6O4, Mr = 756.34) belongs to the monoclinic system, space group P21/c with a = 19.043(10), b = 10.808(5), c = 18.704(11)A, β= 115.540(6)°, V = 3473(3) A3, Z = 4, Dc = 1.446 g/cm^3, S = 1.3, μ = 0.733 mm-1, F(000) = 1544, the final R = 0.1219 and wR = 0.2681 for 7811 independent reflections. The Mn ion adopts a distorted octahedral geometry coordinated by two deprotonated H2pbmCl2 ligands and two DMF molecules. The [MnIII(HpbmCl2)(pbmCl2)(DMF)2] molecules are arranged into a three-dimensional structure through hydrogen bonds(N–H…N, C–H…N and C–H…Cl) and weak π···πinteractions. The activity measurements suggest that complex 2 is able to serve as a catalyst for H2O2 disproportionation reaction to form O2 in neutral water solution.
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.
文摘Development of active iron based water oxidation for designing an ideal artificial photosynthesis devices operating under benign neutral pH is highly demanded. We investigated the electrocatalytic activity of Ruddlesden-Pop-per-type strontium ferrite (Sr3Fe2O7) toward the oxygen evolution reaction (OER). Owing to the temperature-dependent efficiency of the charge disproportionation of Fe4+, the OER activity of Sr3Fe2O7 varied with the temperature, and the onset potential for the OER at a neutral pH underwent a negative shift of approximately 200 mV by increasing the temperature for the stabilization of Fe4+. When metal substitution was made to Sr3Fe2O7 for stabilizing Fe4+ at room temperature, the temperature dependence of the OER activity disappeared and the OER was driven at a small overpotential without increasing the temperature, indicating that the stabilization of Fe4+ is substantially important for achieving high OER activity.
基金supported by a Grant-in-Aid for Scientific Research (KAKENHI, 20226016)a JSPS Fellowship (KAKENHI, 11J03322) from the Japan Society for the Promotion of Science (JSPS) which supported the work of T K, who is a JSPS Research Fellow (DC2)
文摘A carbon-supported Ru catalyst, Ru/BP2000, is able to simultaneously convert cellobiose into sorbitol and gluconic acid. This reaction occurs as the result of hydrolytic disproportionation in water at 393 K under an Ar atmosphere, without bases or sacrificial reagents. In-situ XANES measurements suggest that the active Ru species involved is composed of partially oxidized Ru metal.
基金Project supported by the National Natural Science Foundation of China(Grant No.51101167)the Ningbo Natural Science Foundation,China(Grant No.2013A610075)+4 种基金the Ningbo Science and Technology Project,China(Grant No.2013B10004)the Program of International Science and Technology Cooperation of China(Grant No.2010DFB53770)the China Postdoctoral Science Foundation(Grant No.2012M520943)the State Key Program of the National Natural Science Foundation of China(Grant No.2011AA03A401)the National Key Technologies R&D Program of China(Grant No.2012BAE01B03)
文摘The influence of the RE-rich phase distribution in the precursor alloys on the anisotropy of the hydrogenation disproportionation desorption recombination(HDDR) processed powders is investigated. The homogenized ingot alloy and the as-cast strip casting(SC) alloy with a uniform RE-rich grain boundary phase lead to high anisotropy of the refined powders,acquiring degrees of alignment(DOA) of 0.62 and 0.54, respectively. The RE-rich phase aggregation results in a deteriorated DOA of the powders due to the drastic disproportionation rate, while a thin and uniform RE-rich phase distribution is beneficial for DOA. A reaction model of the initial particle microstructure is proposed for optimizing the HDDR powder anisotropy.
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In the solvothermal condition, a Pd(II) complex with a in situ synthesis ligand, [Pd(2,2’-bipy)2(CN)2] (1) was obtained and characterized by elemental analysis, IR, UV, TG, and powder X-ray analysis. The single crystal X-ray analysis showed that the title complex is different from the reported 2,2’-bipyridyl-dicyanopalladium(II) (2) in crystal system and structural parameters. The catalytic investigation for the reactions of the disproportionation of hydrogen peroxide and oxidation of sulfide showed that the complex 1 is an active homogeneous catalyst in the presence of imidazole and 2-sulfobenzoic acid, respectively.
文摘In the equation U = I – A for the Mott energy, the electron-hole interaction of the successor state is missing. Adding the attractive term, the energy for disproportionation (Hubbard U), may adopt any sign. The missing term is related to the Born effect, the Madelung correction and the Lattice Enthalpy.
文摘Shipping industry has become more capital intensive, technically more demanding and subject to major global regulatory reforms. As a consequence, the number of African shipping lines has been severely reduced. International trade of the WCA countries remains weak, limited to 30% of their Gross Domestic Product (GDP). The goal of this paper is to provide a comprehensive overview of the port and shipping convey management in the WCA region, and of course to describe what has been achieved since then and what still have to be done to better its infrastructures and port community.
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.
基金supported by National Natural Science Foundation of China(Nos.21831003,21801090 and 22293041)China Postdoctoral Science Foundation(No.2019M661203)Users with Excellence Program of Hefei Science Center CAS(No.2020HSC-UE002).
文摘Superlattices in crystals,particularly in perovskite oxides with strong correlation effects,can create new states of matter and produce peculiar physicochemical phenomena.However,the newfangled perovskite superlattices depend on physical deposition with unit-cell precision.It has been challenging to explore a new suitable chemical method to tailor perovskite superlattices.Herein,we present a new bottomup strategy to precisely prepare atomic-scale oxide superlattices of(LaMnO_(3))_(1)-(La_(1-x-y)Ca_(x)K_(y)MnO_(3))_(2)in a monodispersed perovskite La_(0.66)Ca_(0.29)K_(0.05)MnO_(3)(LCKMO).The special atomic-scale perovskite superlattices are demonstrated using SAED,HAADF-STEM,XRD,and atomic-resolution elemental mapping.Our experiments reveal that the perovskite superlattices can be fabricated under extreme hydrothermal conditions utilizing ultra-high concentrations of KOH.An approximate molten salt system in the hydrothermal process can induce the disproportionation reaction of MnO_(2)solids,which is vital to the growth of ordered perovskite superlattices.This work not only clarifies the hydrothermal growth process of perovskite oxides in extreme conditions,but also proposes a novel engineering route toward perovskite superlattices.
基金supported by Natural Science Foundation of Guangxi Province(Grant No.2021GXNSFAA220118)National Natural Science Foundation of China(Grant No.51801035).
文摘TiC coating on 316L stainless steel surface is prepared by molten salt disproportionation reaction by using carbon layer converted from organic carbon solution as carbon source.The Raman and morphology characterizations show that the carbon layer and TiC coating are successfully prepared on the surface of 316L stainless steel,the prepared carbon layer and 316L matrix have good adhesion,and the prepared TiC coating is smooth and dense.In the simulated cathodic environment of the proton exchange membrane fuel cell,the potentiostatic and potentiodynamic polarization measurements show that the TiC coating has smaller and more stable current density fluctuation than the 316L stainless steel substrate,and the electrochemical impedance test lasting for 275 h still shows better stable corrosion resistance than that of the 316L stainless steel substrate.Finally,in the water contact angle and interface contact resistance tests,the TiC coating consistently maintained better hydrophobicity and lower interface contact resistance values than 316L stainless steel.
基金supported by the National Natural Science Foundation of China(Grant Nos.12172047 and 92163101)the Beijing Natural Science Foundation(Grant No.Z190011)+1 种基金the National Technologies Key Research and Development Program of China(Grant No.2019YFA0307900)Y.Lun acknowledges the support from the Graduate Technological Innovation Project of Beijing Institute of Technology(Grant No.2019CX20002).
文摘Driven by the minimization of total energy,the multi-domain morphology is preferred in as-grown ferroelectrics to reduce the depolarization and strain energy during the paraelectric to ferroelectric phase transition.However,the complicated multi-domain is not desirable for certain high-performance ferroelectric electro-optic devices.In this work,we achieve a reproducible and stable large-area monodomain in as-grown bulk ferroelectric single crystal Sn_(2)P_(2)S_(6).The monodomain dominates the entire single crystal,which is attributed to the internal charge carriers from the photoexcited disproportionation reaction of Sn ions.The charge carriers effectively screen the depolarization field and therefore decrease the depolarization energy and facilitate the formation of monodomain.This work offers a potential approach for engineering bulk ferroelectrics with a stable monodomain,which is desirable for the high-performance ferroelectric electro-optic devices.