The amorphous boron powders with high activity were prepared by the high-energy ball milling-combustion synthesis method. The effects of the milling rate and milling time on the crystallinity, microscopic morphology a...The amorphous boron powders with high activity were prepared by the high-energy ball milling-combustion synthesis method. The effects of the milling rate and milling time on the crystallinity, microscopic morphology and reactivity of amorphous boron powder were studied. The results show that the crystallinity of amorphous nano-boron powder is only 22.5%, and its purity reaches 92.86%. The high-energy ball milling can significantly refine boron powder particle sizes, whose average particle sizes are smaller than 50 nm, and specific surface areas are of up to 70.03 m2/g. When the transmission electron beam irradiates the samples, they rapidly melt. It can be seen that the monomer amorphous boron size is less than 30 nm from the specimen melting traces, which indicates that the samples have high reactivity.展开更多
The preparation process of amorphous nanometer boron powders through combustion synthesis was investigated, and the effects of the reactant ratio, the heating agent and the milling rate on the activity and particle si...The preparation process of amorphous nanometer boron powders through combustion synthesis was investigated, and the effects of the reactant ratio, the heating agent and the milling rate on the activity and particle size of amorphous boron powders were studied. The results show that the boron powders exist in the form of an amorphous phase which has the crystallinity lower than 30.4%, and the panicle size of boron powder decreases with an increase of the high-energy ball milling rate. The purity of amorphous boron powder is 94.8% and panicle sizes are much smaller than 100 nm when the mass ratio of B2O3/Mg/KClO3 is 100：105：17 and the ball milling time is 20 min with the milling rate of 300 r/min. At the same time, the amorphous boron nano-fibers appear in the boron powders.展开更多
The problem of low disposal and utilization rate of bulk industrial solid waste needs to be solved.In this paper,a high-activity admixture composed of steel slag-phosphate slag-limestone powder was proposed for most o...The problem of low disposal and utilization rate of bulk industrial solid waste needs to be solved.In this paper,a high-activity admixture composed of steel slag-phosphate slag-limestone powder was proposed for most of the solid waste with low activity and a negative impact on concrete workability,combining the characteristics of each solid waste.The paper demonstrates the feasibility and explains the principle of the composite system in terms of water requirement of standard consistency,setting time,workability,and mechanical properties,combined with the composition of the phases,hydration temperature,and microscopic morphology.The results showed that the steel slag:phosphate slag:limestone=5:2:3 gave the highest activity of the composite system,over 92%.Besides,the composite system had no significant effect on water demand and setting time compared to cement,and it could significantly increase the 7 and 28 d activity of the system.The composite system delayed the exothermic hydration of the cement and reduced the exothermic heat but had no effect on the hydration products.Therefore,the research in this paper dramatically improved the solid waste dissipation in concrete,reduced the amount of cement in concrete and positively responded to the national slogan of carbon neutral and peaking.展开更多
The nitrogen-coordinated metal single-atom catalysts(M−N−C SACs)with an ultra-high metal loading synthetized by direct high-temperature pyrolysis have been widely reported.However,most of metal single atoms in these c...The nitrogen-coordinated metal single-atom catalysts(M−N−C SACs)with an ultra-high metal loading synthetized by direct high-temperature pyrolysis have been widely reported.However,most of metal single atoms in these catalysts were buried in the carbon matrix,resulting in a low metal utilization and inaccessibility for adsorption of reactants during the catalytic process.Herein,we reported a facile synthesis based on the hard-soft acid-base(HSAB)theory to fabricate Co single-atom catalysts with highly exposed metal atoms ligated to the external pyridinic-N sites of a nitrogen-doped carbon support.Benefiting from the highly accessible Co active sites,the prepared Co−N−C SAC exhibited a superior oxygen reduction reactivity comparable to that of the commercial Pt/C catalyst,showing a high turnover frequency(TOF)of 0.93 e^(−)·s^(-1)·site^(-1)at 0.85 V vs.RHE,far exceeding those of some representative SACs with a ultra-high metal content.This work provides a rational strategy to design and prepare M−N−C single-atom catalysts featured with high site-accessibility and site-density.展开更多
Because of an unfortunate mistake by authors,the Project(5227010679)of Foundation item was wrong.The corrected Project is shown as follows:Project(52271073).
A series of transition metals(Fe,Co,Ni,Cu,Cr and Mn)-doped CeO_(2)-TiO_(2) catalysts were prepared by the sol-gel method and applied for the catalytic removal of 1,2-dichloroethane(DCE) as a model for chlorinated VOCs...A series of transition metals(Fe,Co,Ni,Cu,Cr and Mn)-doped CeO_(2)-TiO_(2) catalysts were prepared by the sol-gel method and applied for the catalytic removal of 1,2-dichloroethane(DCE) as a model for chlorinated VOCs(CVOCs).The various characterization methods including X-ray diffraction(XRD),N_(2) adsorption-desorption,UV-Raman,NH_(3) temperature-programmed desorption(NH_(3)-TPD) and H_(2) temperature-programmed reduction(H_(2)-TPR) were utilized to investigate the physicochemical properties of the catalysts.The results show that doping Fe,Co,Ni or Mn can obviously promote the activity of CeO_(2)-TiO_(2) mixed oxides for DCE degradation,which is related to their improved texture properties,acid sites(especially for strong acidity) and low-temperature reducibility.Particularly,CeTi-Fe doped with moderate Fe exhibits excellent activity for 1,2-dichloroethane(DCE) degradation,giving a T_(90%) value as low as 250℃.More importantly,only trace chlorinated byproducts were produced during the low-temperature degradation of various CVOCs(dichloromethane(DCM),trichloroethylene(TCE) and chlorobenzene(CB)) over CeTi-Fe1/9 catalyst with high durability.展开更多
Catalytic hydrogenation is an appropriate method for the improvement of C9 petroleum resin（C9PR） quality. In this study, the Ni2P/SiO2（containing 10% of Ni） catalyst prepared by the temperature-programmed reductio...Catalytic hydrogenation is an appropriate method for the improvement of C9 petroleum resin（C9PR） quality. In this study, the Ni2P/SiO2（containing 10% of Ni） catalyst prepared by the temperature-programmed reduction（TPR） method was used for hydrogenation of C9 petroleum resins. The effect of reaction conditions on catalytic performance was studied, and the results showed that the optimum reaction temperature, pressure and liquid hourly space velocity（LHSV） was 250 ℃, 6.0 MPa, and 1.0 h-1, respectively. The bromine numbers of hydrogenated products were maintained at low values（250 mg Br/100g） within 300h, showing the high activity and stability of Ni2P/SiO2 catalyst. The fresh and spent catalysts were characterized by X-ray diffraction（XRD）, BET surface area（BET） analysis, scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, Fourier transform infrared（FTIR） pyridine adsorption, and X-ray photoelectron spectroscopy（XPS）. Compared with the traditional sulfurated-Ni W catalysts, Ni2P possessed globe-like structure instead of layered structure like the active phase of Ni WS, thereof exposing more active sites, which were responsible for the high activity of Ni2P/SiO2 catalyst. The stability of Ni2P/SiO2 catalyst was probably attributed to its high sulfur tolerance, antisintering, anti-coking and carbon-resistance ability. These properties might be further ascribed to the special Ni-P-S surface phase, high thermal stability of Ni2P nanoparticles and weak surface acidity for the Ni2P/SiO2 catalyst.展开更多
Currently,endeavors to scale up the production of amorphous catalysts are still impeded by intricate synthesis conditions.Here,we have prepared a series of metal-based molybdate via one-step coprecipitation method.Aft...Currently,endeavors to scale up the production of amorphous catalysts are still impeded by intricate synthesis conditions.Here,we have prepared a series of metal-based molybdate via one-step coprecipitation method.After ingredient optimization,amorphous Co_(2)CeFe_(2)-MoO_(4) was identified as exhibiting the highest intrinsic activity among its counterparts.Modulation of electron structure enables Co_(2)CeFe_(2)-MoO_(4) to balance the adsorption behavior towards reactive intermediates.Ultimately,the obtained Co_(2)CeFe_(2)-MoO_(4) molybdate demonstrated a captivating OER performance,showcasing a low overpotential of 230 mV at 10 mA cm^(-2).Moreover,the alkaline electrolyzer employing the Co_(2)CeFe_(2)-MoO_(4) anode exhibited a low cell voltage of 1.50 V for water splitting and underwent an acceptable attenuation of 4.99% after 165 h of continuous operation,demonstrating its favorable catalytic activity and durability.This work provides a facile and eco-friendly synthesis pathway for crafting cost-effective and durable earth-abundant OER electrocatalysts tailored for water splitting to produce clean hydrogen.展开更多
Oxygen evolution reaction（OER） is one of the most important reactions in the energy storage devices such as metal–air batteries and unitized regenerative fuel cells（URFCs）. However, the kinetically sluggishness o...Oxygen evolution reaction（OER） is one of the most important reactions in the energy storage devices such as metal–air batteries and unitized regenerative fuel cells（URFCs）. However, the kinetically sluggishness of OER and the high prices as well as the scarcity of the most active precious metal electrocatalysts are the major bottleneck in these devices. Developing low-cost non-precious metal catalysts with high activity and stability for OER is highly desirable. A facile, in situ template method combining the dodecyl benzene sulfuric acid sodium（SDBS） assisted hydrothermal process with subsequent high-temperature treatment was developed to prepare porous Co3O4 with improved surface area and hierarchical porous structure as precious catalysts alternative for oxygen evolution reaction（OER）. Due to the unique structure, the as-prepared catalyst shows higher electrocatalytic activity than Co3O4 prepared by traditional thermal-decomposition method（noted as Co3O4-T） and commercial IrO2 catalyst for OER in 0.1M KOH aqueous solution. Moreover, it displays improved stability than Co3O4-T. The results demonstrate a highly efficient, scalable, and low cost method for developing highly active and stable OER electrocatalysts in alkaline solutions.展开更多
Excellent catalysts with low-temperature activity and relatively wide temperature window for selective catalytic reduction of NO with ammonia(NH_(3)-SCR) are highly demanded in view of the practical treatment of NO.He...Excellent catalysts with low-temperature activity and relatively wide temperature window for selective catalytic reduction of NO with ammonia(NH_(3)-SCR) are highly demanded in view of the practical treatment of NO.Herein,we have designed a highly active VOx-MnOx/CeO_(2) material based on the intrinsic requirement of SCR reaction for catalyst,namely redox sites and surface acid sites.The vanadium oxide and manganese oxide are highly dispersed over the ceria mesosphere via simple incipient wetness impregnation.The loading of manganese could introduce acid sites and enhance the redox property remarkably,while the loading of vanadium increases acid sites and weakens redox property.Through tentatively controlling the appropriate loading ratio of the two components,the optimal catalyst achieves a balance between redox property and surface acidity.The work shed light on the development of new SCR catalyst with superior low temperature activity,wide work temperature window and good hydrothermal stability.展开更多
The effects of highly active antiretroviral therapy （HAART） to patients with AIDS in Hubei province of China were investigated in order to provide scientific evidence to reinforce the management of HAART. Self-made ...The effects of highly active antiretroviral therapy （HAART） to patients with AIDS in Hubei province of China were investigated in order to provide scientific evidence to reinforce the management of HAART. Self-made questionnaires and descriptive method of epidemiology were used to collect and describe the changes of clinical symptoms, HIV RIgA concentration, and immune function of patients with AIDS. After HAART, the effective rate of fever, cough, diarrhea, lymphadenectasis, weight loss, tetter, debility and fimgous infection was 92.4%, 90.85%, 92.91%, 90.73%, 93.69%, 89.04%, 92.34%, and 83.1%, respectively. Of 117 patients with detected HIV RNA concentration, 41.03% had declined over 0.5 log, and 52.99% less than 0.5 log. CD4^＋T cell count was obviously increased： the average number after HAART for 3 or 6 months was 237μL （26-755μL） and 239μL （17-833μL）, respectively HAART can improve AIDS patients＇ clinical symptoms, reduce HIV RNA concentration, and maintain immune function. It is very important for the effectiveness of HAART to raise clinical adherence of pa- tients with AIDS and have a persistent surveillance.展开更多
The recrystallization behavior of a low carbon high niobium microalloyed steel was investigated using continuous and interrupted hot compression tests. The results showed that the initiation of dynamic recrystallizati...The recrystallization behavior of a low carbon high niobium microalloyed steel was investigated using continuous and interrupted hot compression tests. The results showed that the initiation of dynamic recrystallization （DRX） could be detected from inflection in the plot of the strain hardening rate against stress regardless of the stress peak appearance. According to the Zener-Hollomon parameter equation, the activity energy of DRX （Qad） was ob tained and a new modified expression calculating Qdef was proposed in consideration of the chemical composition of experimental steel. Applying the 2% offset method, the static softening fraction was determined. The graphic representation of the softening fraction vs interruption time gave the information about the non-static reerystallization temperature （about 1 000℃ ） and the relationship of precipitation time temperature. Static recrystallization kinetics followed the Avrami＇s law at high deformation temperature, and different values of the exponent m were given to illustrate the effect of niobium element on static recrystallization at different deformation temperatures.展开更多
Objective To investigate the response on late stage Chinese AIDS patients after highly active antiretroviral therapy （HAART）. Methods From October 2002 to March 2004, 20 cases of late stage Chinese AIDS patients we...Objective To investigate the response on late stage Chinese AIDS patients after highly active antiretroviral therapy （HAART）. Methods From October 2002 to March 2004, 20 cases of late stage Chinese AIDS patients were selected to participate in this opened and randomised study, we purposely chose those with CD4＋ T cell counts 〈 100/mm^3. All of them had one or two opportunistic infections and none had been treated with anti-HIV drugs. All patients were tested with CD4＋ （naive CD4＋ T cell defined by CD45RA＋ and CD62L＋, memory CD4＋ T cell defined by CD45RA-）, CD8＋ T cell, plasma HIV viral load, and clinical manifestations on before, during, and after HAART （5 different regimes） on 1, 3, 6, 9, and 12 months. Before HAART mean CD4＋ T cell counts were 32 ± 31 （range 2-91）/mm^3, and plasma HIV viral load were 5.07 ± 0.85（range 2.04-5.70） log copies/mL. In 1 month＇s time patients treated with HAAT had mean CD4＋ and CD8＋ T cell counts increasing rapidly. After 1 month the increasing speed turned to slow down, but HIV viral load decreased predominantly within the first 3 months. The major part of increasing CD4＋ T cells were memory CD4＋ T cells, as for naive CD4＋ T cells increasing low and slow. Clinical symptoms and signs improved, and opportunistic infections reduced. The quality of life will be far much better than before. Each patient was followed for 12 months, and had finished 12 months＇ HAAT. Conclusion This is the first report in China that late stage Chinese AIDS patients after HAART could have their immune reconstitution. The regular pattern is similar to what had been reported in Western countries and also in China. So it is worth to treat late stage Chinese AIDS patients with HAAT.展开更多
The freshly prepared water-wet amidoximated bacterial cellulose （Am-BC） serves as an effective nanoreactor to synthesis zinc oxide nanoparticles by in situ polyol method. The obtained ZnO/Am-BC nanocomposites have b...The freshly prepared water-wet amidoximated bacterial cellulose （Am-BC） serves as an effective nanoreactor to synthesis zinc oxide nanoparticles by in situ polyol method. The obtained ZnO/Am-BC nanocomposites have been characterized by field emission scanning electron microscopy （FE-SEM）, X-ray diffraction （XRD）, Fourier transformed infrared spectroscopy （FTIR） and thermogravimetric analysis （TGA）. The influence of the zinc acetate concentration on the morphologies and size ofZnO nanoparticles and the possible formation mechanism were discussed. The results indicated that uniform ZnO nanoparticles were homogeneously anchored on the Am-BC nanofibers through strong interaction between the hydroxyl and amino groups of Am-BC and ZnO nanoparticles. The loading content of ZnO nanoparticles is higher using Am-BC as a template than using the unmodified bacterial cellulose. The resultant nanocomposite synthesized at 0.05 wt% shows a high photocatalytic activity （92%） in the degradation of methyl orange.展开更多
Using a walnut shellas a carbon source and ZnCl_2 as an activating agent,we resolved the temperature gradient problems of activated carbon in the microwave desorption process.An appropriate amount of silicon carbide w...Using a walnut shellas a carbon source and ZnCl_2 as an activating agent,we resolved the temperature gradient problems of activated carbon in the microwave desorption process.An appropriate amount of silicon carbide was added to prepare the composite activated carbon with high thermalconductivity while developing VOC adsorption-microwave regeneration technology.The experimentalresults show that the coefficient of thermalconductivity of SiC-AC is three times as much as those of AC and SY-6.When microwave power was 480 W in its microwave desorption,the temperature of the bed thermaldesorption was 10 ℃ to 30 ℃ below that of normalactivated carbon prepared in our laboratory.The toluene desorption activation energy was 16.05 k J·mol^（-1）,which was 15% less than the desorption activation energy of commercialactivated carbon.This study testified that the process could maintain its high adsorption and regeneration desorption performances.展开更多
Electrode materials have an important effect on the property of microbial fuel cell(MFC). Carbon foam is utilized as an anode and further modified by urea to improve its performance in marine benthic microbial fuel ce...Electrode materials have an important effect on the property of microbial fuel cell(MFC). Carbon foam is utilized as an anode and further modified by urea to improve its performance in marine benthic microbial fuel cell(BMFC) with higher voltage and output power. The electrochemical properties of plain carbon foam(PC) and urea-modified carbon foam(UC) are measured respectively. Results show that the UC obtains better wettability after its modification and higher anti-polarization ability than the PC. A novel phenomenon has been found that the electrical potential of the modified UC anode is nearly 100 m V lower than that of the PC, reaching-570 ±10 m V(vs. SCE), and that it also has a much higher electron transfer kinetic activity, reaching 9399.4 m W m-2, which is 566.2-fold higher than that from plain graphite anode(PG). The fuel cell containing the UC anode has the maximum power density(256.0 m W m-2) among the three different BMFCs. Urea would enhance the bacteria biofilm formation with a more diverse microbial community and maintain more electrons, leading to a lower anodic redox potential and higher power output. The paper primarily analyzes why the electrical potential of the modified anode becomes much lower than that of others after urea modification. These results can be utilized to construct a novel BMFC with higher output power and to design the conditioner of voltage booster with a higher conversion ratio. Finally, the carbon foam with a bigger pore size would be a potential anodic material in conventional MFC.展开更多
In this paper, a close relationship between the intraseasonal variation of subtropical high over East Asia and the convective activities around the South China Sea and the Philippines is analysed from OLR data.This re...In this paper, a close relationship between the intraseasonal variation of subtropical high over East Asia and the convective activities around the South China Sea and the Philippines is analysed from OLR data.This relationship is studied by using the theory of wave propagating in a slowly varying medium and by using a quasi-geoslrophic, linear, spherical model and the IAP-GCM, respectively. The results show that when the SST is warming around the western tropical Pacific or the Philippines, the convective activities are intensified around the Philippines. As a consequence, the subtropical high will be intensified over East Asia. The computed results also show that when the anomaly of convective activities are caused around the Philippines, a teleconnection pattern of circulation anomalies will be caused over South Asia, East Asia and North America.展开更多
Objectives： The study assessed if the level of knowledge of HIV-infected about HAART and waiting-times in the PHC （primary healthcare） clinic have an influence on antiretroviral adherence. Methods： A descriptive-c...Objectives： The study assessed if the level of knowledge of HIV-infected about HAART and waiting-times in the PHC （primary healthcare） clinic have an influence on antiretroviral adherence. Methods： A descriptive-cross-sectional study was conducted in South Africa. Data collected uses a standardized-questionnaire and face-to-face-exit interviews. Pill-count technique was performed and a value of≥ 95% acceptable. Data were analysed using SPSS. Univariate-factors associated with poor-adherence to knowledge about HAART and waiting times were assessed using ANOVA and p ≤ 0.05 considered statistically significant. Key findings： Of 86 enrolled, 63（73.3%） were females and 23（26.7%） males, with mean-age （± SD） of 35.6（±9.6） years and on HAART for 35.5（± 31.8） months ranging from 1-137. Of these, 27（31.40%） and 25（29.07%） were on WHO stages 2 and 3 respectively. Adherence-rates computed from 32 patients, 23（71.9%） revealed poor adherence-rates. The level of knowledge about HAART in terms of names of tablets, correct-dose, frequency, adverse-effects had no influence on ARV-adherence （p _〉 0.05）. Of 23 non-compliant, 10 （40%） gave the reason of drugs-unavailability, 7（30%） adverse-effects, 5（20%） drugs＇ complexity, and 1（10%） too busy to take them. Waiting areas associated with poor ARV-adherence were reception （p = 0.028）, doctors （p = 0.027）, while nurse＇s station （p = 0.29） and pharmacy （p = 0.43） revealed acceptable ARV-adherence.展开更多
Cytomegalovirus(CMV)retinitis is an opportunistic infection that has traditionally affected those who have HIV/AIDS or immunosuppressed individuals.CMV retinitis previously infected one-third of AIDS patients in the p...Cytomegalovirus(CMV)retinitis is an opportunistic infection that has traditionally affected those who have HIV/AIDS or immunosuppressed individuals.CMV retinitis previously infected one-third of AIDS patients in the pre-highly active antiretroviral therapy(HAART)era,but since HAART,Western countries have seen an 80%decrease in the incidence of the disease.More recently,CMV retinitis has been reported in patients who are immunosuppressed,often due to chemotherapy or immunomodulatory medications.The diagnosis of CMV retinitis is often suspected based on clinical findings,with polymerase chain reaction for confirmation of CMV,especially in atypical cases.Highly active antiretroviral therapy and anti-CMV medications(systemic or local)remain the mainstay of treatment.However,for those who are not responsive to HAART,CMV retinitis remains a challenge,and can still lead to significant vision loss.Moreover,a regimen of anti-CMV medications can sometimes lead to viral resistance or organ toxicity.Complications such as immune recovery retinitis and rhegmatogenous retinal detachments continue to threaten the vision of patients who develop CMV retinitis.These complications can arise following initiation of treatment or if patients show disease progression.Proper vision screening for CMV retinitis in immunosuppressed patients at-risk is necessary for early detection and treatment.展开更多
Soft N-donor bis-triazin bipyridines derives(R-BTBP)are a type of very promising extratant for extraction and complexation with long-lived trivalent minor actinides over lanthanides from highly active liquid waste(HLW...Soft N-donor bis-triazin bipyridines derives(R-BTBP)are a type of very promising extratant for extraction and complexation with long-lived trivalent minor actinides over lanthanides from highly active liquid waste(HLW).In addition to minor actinides,R-BTBP also holds very strong complexation ability toward fission palladium.However,few studies have been focused on the separation and complexation with the fission product Pd(Ⅱ)by R-BTBP.Herein,the complexation behaviors of Pd(Ⅱ)with four typical R-BTBP ligands were systematically studied by single crystal X-ray diffraction,1H NMR titration and theoretical calculation.The effects of R-BTBP initial conformation and nitrate anions on the complexation behaviors of R-BTBP with Pd(Ⅱ)were thoughtfully analyzed.Both the 1:1 and 2:1 binuclear complexes could be formed between Pd(Ⅱ)and R-BTBP with initialⅡconformation in the presence of nitrate anions,while only one 1:1 type Pd(Ⅱ)complex could be formed for those with initial OO conformation.Without nitrate anion,only one 1:1 type complex was formed in solution.The structure of the 1:1 Pd(Ⅱ)/R-BTBP complex was firstly characterized by single crystal crystallography.DFT calculation results showed that a significant large rotational energy barrier(21.8~22.6 kcal/mol)must be overcome to form theⅡtype 2:1Pd(Ⅱ)complex for those OO type R-BTBP ligands,however which would not prevent them from forming the 1:1 type complex.展开更多
基金Project(51002025)supported by the National Natural Science Foundation of China
文摘The amorphous boron powders with high activity were prepared by the high-energy ball milling-combustion synthesis method. The effects of the milling rate and milling time on the crystallinity, microscopic morphology and reactivity of amorphous boron powder were studied. The results show that the crystallinity of amorphous nano-boron powder is only 22.5%, and its purity reaches 92.86%. The high-energy ball milling can significantly refine boron powder particle sizes, whose average particle sizes are smaller than 50 nm, and specific surface areas are of up to 70.03 m2/g. When the transmission electron beam irradiates the samples, they rapidly melt. It can be seen that the monomer amorphous boron size is less than 30 nm from the specimen melting traces, which indicates that the samples have high reactivity.
基金Project(51002025) supported by the National Natural Science Foundation of China
文摘The preparation process of amorphous nanometer boron powders through combustion synthesis was investigated, and the effects of the reactant ratio, the heating agent and the milling rate on the activity and particle size of amorphous boron powders were studied. The results show that the boron powders exist in the form of an amorphous phase which has the crystallinity lower than 30.4%, and the panicle size of boron powder decreases with an increase of the high-energy ball milling rate. The purity of amorphous boron powder is 94.8% and panicle sizes are much smaller than 100 nm when the mass ratio of B2O3/Mg/KClO3 is 100：105：17 and the ball milling time is 20 min with the milling rate of 300 r/min. At the same time, the amorphous boron nano-fibers appear in the boron powders.
基金Key Research and Development Plan of Shaanxi Province(2019TSLGY05-04).
文摘The problem of low disposal and utilization rate of bulk industrial solid waste needs to be solved.In this paper,a high-activity admixture composed of steel slag-phosphate slag-limestone powder was proposed for most of the solid waste with low activity and a negative impact on concrete workability,combining the characteristics of each solid waste.The paper demonstrates the feasibility and explains the principle of the composite system in terms of water requirement of standard consistency,setting time,workability,and mechanical properties,combined with the composition of the phases,hydration temperature,and microscopic morphology.The results showed that the steel slag:phosphate slag:limestone=5:2:3 gave the highest activity of the composite system,over 92%.Besides,the composite system had no significant effect on water demand and setting time compared to cement,and it could significantly increase the 7 and 28 d activity of the system.The composite system delayed the exothermic hydration of the cement and reduced the exothermic heat but had no effect on the hydration products.Therefore,the research in this paper dramatically improved the solid waste dissipation in concrete,reduced the amount of cement in concrete and positively responded to the national slogan of carbon neutral and peaking.
基金supported by Shanxi Province Science Foundation for Youths(202203021212300)Taiyuan University of Science and Technology Scientific Research Initial Funding(20212064)Outstanding Doctoral Award Fund in Shanxi Province(20222060).
文摘The nitrogen-coordinated metal single-atom catalysts(M−N−C SACs)with an ultra-high metal loading synthetized by direct high-temperature pyrolysis have been widely reported.However,most of metal single atoms in these catalysts were buried in the carbon matrix,resulting in a low metal utilization and inaccessibility for adsorption of reactants during the catalytic process.Herein,we reported a facile synthesis based on the hard-soft acid-base(HSAB)theory to fabricate Co single-atom catalysts with highly exposed metal atoms ligated to the external pyridinic-N sites of a nitrogen-doped carbon support.Benefiting from the highly accessible Co active sites,the prepared Co−N−C SAC exhibited a superior oxygen reduction reactivity comparable to that of the commercial Pt/C catalyst,showing a high turnover frequency(TOF)of 0.93 e^(−)·s^(-1)·site^(-1)at 0.85 V vs.RHE,far exceeding those of some representative SACs with a ultra-high metal content.This work provides a rational strategy to design and prepare M−N−C single-atom catalysts featured with high site-accessibility and site-density.
文摘Because of an unfortunate mistake by authors,the Project(5227010679)of Foundation item was wrong.The corrected Project is shown as follows:Project(52271073).
基金Project supported by the National Key Research and Development Program of China(2016YFC0204300)the National Natural Science Foundation of China(21477109)。
文摘A series of transition metals(Fe,Co,Ni,Cu,Cr and Mn)-doped CeO_(2)-TiO_(2) catalysts were prepared by the sol-gel method and applied for the catalytic removal of 1,2-dichloroethane(DCE) as a model for chlorinated VOCs(CVOCs).The various characterization methods including X-ray diffraction(XRD),N_(2) adsorption-desorption,UV-Raman,NH_(3) temperature-programmed desorption(NH_(3)-TPD) and H_(2) temperature-programmed reduction(H_(2)-TPR) were utilized to investigate the physicochemical properties of the catalysts.The results show that doping Fe,Co,Ni or Mn can obviously promote the activity of CeO_(2)-TiO_(2) mixed oxides for DCE degradation,which is related to their improved texture properties,acid sites(especially for strong acidity) and low-temperature reducibility.Particularly,CeTi-Fe doped with moderate Fe exhibits excellent activity for 1,2-dichloroethane(DCE) degradation,giving a T_(90%) value as low as 250℃.More importantly,only trace chlorinated byproducts were produced during the low-temperature degradation of various CVOCs(dichloromethane(DCM),trichloroethylene(TCE) and chlorobenzene(CB)) over CeTi-Fe1/9 catalyst with high durability.
基金financially supported by the Scientific Research Fund of Zhejiang Provincial Education Department (Y201225114)the Natural Science Foundation of Zhejiang Province (LY13B030006)
文摘Catalytic hydrogenation is an appropriate method for the improvement of C9 petroleum resin（C9PR） quality. In this study, the Ni2P/SiO2（containing 10% of Ni） catalyst prepared by the temperature-programmed reduction（TPR） method was used for hydrogenation of C9 petroleum resins. The effect of reaction conditions on catalytic performance was studied, and the results showed that the optimum reaction temperature, pressure and liquid hourly space velocity（LHSV） was 250 ℃, 6.0 MPa, and 1.0 h-1, respectively. The bromine numbers of hydrogenated products were maintained at low values（250 mg Br/100g） within 300h, showing the high activity and stability of Ni2P/SiO2 catalyst. The fresh and spent catalysts were characterized by X-ray diffraction（XRD）, BET surface area（BET） analysis, scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, Fourier transform infrared（FTIR） pyridine adsorption, and X-ray photoelectron spectroscopy（XPS）. Compared with the traditional sulfurated-Ni W catalysts, Ni2P possessed globe-like structure instead of layered structure like the active phase of Ni WS, thereof exposing more active sites, which were responsible for the high activity of Ni2P/SiO2 catalyst. The stability of Ni2P/SiO2 catalyst was probably attributed to its high sulfur tolerance, antisintering, anti-coking and carbon-resistance ability. These properties might be further ascribed to the special Ni-P-S surface phase, high thermal stability of Ni2P nanoparticles and weak surface acidity for the Ni2P/SiO2 catalyst.
基金supported by the National Natural Science Foundation of China (No. 21872153)。
文摘Currently,endeavors to scale up the production of amorphous catalysts are still impeded by intricate synthesis conditions.Here,we have prepared a series of metal-based molybdate via one-step coprecipitation method.After ingredient optimization,amorphous Co_(2)CeFe_(2)-MoO_(4) was identified as exhibiting the highest intrinsic activity among its counterparts.Modulation of electron structure enables Co_(2)CeFe_(2)-MoO_(4) to balance the adsorption behavior towards reactive intermediates.Ultimately,the obtained Co_(2)CeFe_(2)-MoO_(4) molybdate demonstrated a captivating OER performance,showcasing a low overpotential of 230 mV at 10 mA cm^(-2).Moreover,the alkaline electrolyzer employing the Co_(2)CeFe_(2)-MoO_(4) anode exhibited a low cell voltage of 1.50 V for water splitting and underwent an acceptable attenuation of 4.99% after 165 h of continuous operation,demonstrating its favorable catalytic activity and durability.This work provides a facile and eco-friendly synthesis pathway for crafting cost-effective and durable earth-abundant OER electrocatalysts tailored for water splitting to produce clean hydrogen.
基金supported by the Youth Innovation Promotion Association(no.2015147)CAS and National Program on Key Basic Research Project(973 Program,2012CB215500)+1 种基金the Outstanding Youngest Scientist FoundationChinese Academy of Sciences(CAS)
文摘Oxygen evolution reaction（OER） is one of the most important reactions in the energy storage devices such as metal–air batteries and unitized regenerative fuel cells（URFCs）. However, the kinetically sluggishness of OER and the high prices as well as the scarcity of the most active precious metal electrocatalysts are the major bottleneck in these devices. Developing low-cost non-precious metal catalysts with high activity and stability for OER is highly desirable. A facile, in situ template method combining the dodecyl benzene sulfuric acid sodium（SDBS） assisted hydrothermal process with subsequent high-temperature treatment was developed to prepare porous Co3O4 with improved surface area and hierarchical porous structure as precious catalysts alternative for oxygen evolution reaction（OER）. Due to the unique structure, the as-prepared catalyst shows higher electrocatalytic activity than Co3O4 prepared by traditional thermal-decomposition method（noted as Co3O4-T） and commercial IrO2 catalyst for OER in 0.1M KOH aqueous solution. Moreover, it displays improved stability than Co3O4-T. The results demonstrate a highly efficient, scalable, and low cost method for developing highly active and stable OER electrocatalysts in alkaline solutions.
基金Project supported by the National Natural Science Foundation of China (21576054)Science and Technology Planning of Guangdong Province (2016B020241003)+1 种基金Natural Science Foundation of Guangdong Province(2018A030310563)Foundation of Higher Education of Guangdong Province(2018KZDXM031)。
文摘Excellent catalysts with low-temperature activity and relatively wide temperature window for selective catalytic reduction of NO with ammonia(NH_(3)-SCR) are highly demanded in view of the practical treatment of NO.Herein,we have designed a highly active VOx-MnOx/CeO_(2) material based on the intrinsic requirement of SCR reaction for catalyst,namely redox sites and surface acid sites.The vanadium oxide and manganese oxide are highly dispersed over the ceria mesosphere via simple incipient wetness impregnation.The loading of manganese could introduce acid sites and enhance the redox property remarkably,while the loading of vanadium increases acid sites and weakens redox property.Through tentatively controlling the appropriate loading ratio of the two components,the optimal catalyst achieves a balance between redox property and surface acidity.The work shed light on the development of new SCR catalyst with superior low temperature activity,wide work temperature window and good hydrothermal stability.
文摘The effects of highly active antiretroviral therapy （HAART） to patients with AIDS in Hubei province of China were investigated in order to provide scientific evidence to reinforce the management of HAART. Self-made questionnaires and descriptive method of epidemiology were used to collect and describe the changes of clinical symptoms, HIV RIgA concentration, and immune function of patients with AIDS. After HAART, the effective rate of fever, cough, diarrhea, lymphadenectasis, weight loss, tetter, debility and fimgous infection was 92.4%, 90.85%, 92.91%, 90.73%, 93.69%, 89.04%, 92.34%, and 83.1%, respectively. Of 117 patients with detected HIV RNA concentration, 41.03% had declined over 0.5 log, and 52.99% less than 0.5 log. CD4^＋T cell count was obviously increased： the average number after HAART for 3 or 6 months was 237μL （26-755μL） and 239μL （17-833μL）, respectively HAART can improve AIDS patients＇ clinical symptoms, reduce HIV RNA concentration, and maintain immune function. It is very important for the effectiveness of HAART to raise clinical adherence of pa- tients with AIDS and have a persistent surveillance.
基金Item Sponsored by National Natural Science Foundation of China(51074052)Fundamental Research Funds for Central Universities of China(N100607001)
文摘The recrystallization behavior of a low carbon high niobium microalloyed steel was investigated using continuous and interrupted hot compression tests. The results showed that the initiation of dynamic recrystallization （DRX） could be detected from inflection in the plot of the strain hardening rate against stress regardless of the stress peak appearance. According to the Zener-Hollomon parameter equation, the activity energy of DRX （Qad） was ob tained and a new modified expression calculating Qdef was proposed in consideration of the chemical composition of experimental steel. Applying the 2% offset method, the static softening fraction was determined. The graphic representation of the softening fraction vs interruption time gave the information about the non-static reerystallization temperature （about 1 000℃ ） and the relationship of precipitation time temperature. Static recrystallization kinetics followed the Avrami＇s law at high deformation temperature, and different values of the exponent m were given to illustrate the effect of niobium element on static recrystallization at different deformation temperatures.
文摘Objective To investigate the response on late stage Chinese AIDS patients after highly active antiretroviral therapy （HAART）. Methods From October 2002 to March 2004, 20 cases of late stage Chinese AIDS patients were selected to participate in this opened and randomised study, we purposely chose those with CD4＋ T cell counts 〈 100/mm^3. All of them had one or two opportunistic infections and none had been treated with anti-HIV drugs. All patients were tested with CD4＋ （naive CD4＋ T cell defined by CD45RA＋ and CD62L＋, memory CD4＋ T cell defined by CD45RA-）, CD8＋ T cell, plasma HIV viral load, and clinical manifestations on before, during, and after HAART （5 different regimes） on 1, 3, 6, 9, and 12 months. Before HAART mean CD4＋ T cell counts were 32 ± 31 （range 2-91）/mm^3, and plasma HIV viral load were 5.07 ± 0.85（range 2.04-5.70） log copies/mL. In 1 month＇s time patients treated with HAAT had mean CD4＋ and CD8＋ T cell counts increasing rapidly. After 1 month the increasing speed turned to slow down, but HIV viral load decreased predominantly within the first 3 months. The major part of increasing CD4＋ T cells were memory CD4＋ T cells, as for naive CD4＋ T cells increasing low and slow. Clinical symptoms and signs improved, and opportunistic infections reduced. The quality of life will be far much better than before. Each patient was followed for 12 months, and had finished 12 months＇ HAAT. Conclusion This is the first report in China that late stage Chinese AIDS patients after HAART could have their immune reconstitution. The regular pattern is similar to what had been reported in Western countries and also in China. So it is worth to treat late stage Chinese AIDS patients with HAAT.
基金financially supported by the Program of Introducing Talents of Discipline to Universities(B07024)Shanghai Leading Academic Discipline Project(B603)+1 种基金The National Natural Science Foundation of China(No.51273043)Project of the Action on Scientists and Engineers to Serve Enterprises(2009GJE20016)
文摘The freshly prepared water-wet amidoximated bacterial cellulose （Am-BC） serves as an effective nanoreactor to synthesis zinc oxide nanoparticles by in situ polyol method. The obtained ZnO/Am-BC nanocomposites have been characterized by field emission scanning electron microscopy （FE-SEM）, X-ray diffraction （XRD）, Fourier transformed infrared spectroscopy （FTIR） and thermogravimetric analysis （TGA）. The influence of the zinc acetate concentration on the morphologies and size ofZnO nanoparticles and the possible formation mechanism were discussed. The results indicated that uniform ZnO nanoparticles were homogeneously anchored on the Am-BC nanofibers through strong interaction between the hydroxyl and amino groups of Am-BC and ZnO nanoparticles. The loading content of ZnO nanoparticles is higher using Am-BC as a template than using the unmodified bacterial cellulose. The resultant nanocomposite synthesized at 0.05 wt% shows a high photocatalytic activity （92%） in the degradation of methyl orange.
基金Funded by the National High Technology Research and Development Program of China("863"Program)(No.2006AA06A310)
文摘Using a walnut shellas a carbon source and ZnCl_2 as an activating agent,we resolved the temperature gradient problems of activated carbon in the microwave desorption process.An appropriate amount of silicon carbide was added to prepare the composite activated carbon with high thermalconductivity while developing VOC adsorption-microwave regeneration technology.The experimentalresults show that the coefficient of thermalconductivity of SiC-AC is three times as much as those of AC and SY-6.When microwave power was 480 W in its microwave desorption,the temperature of the bed thermaldesorption was 10 ℃ to 30 ℃ below that of normalactivated carbon prepared in our laboratory.The toluene desorption activation energy was 16.05 k J·mol^（-1）,which was 15% less than the desorption activation energy of commercialactivated carbon.This study testified that the process could maintain its high adsorption and regeneration desorption performances.
基金supported by the Key Project of Natural Science Fund of Shandong Province,China(ZR2011 BZ008)the Special Fund of Marine Renewable Energy from State Ocean Bureau,China(GHME2011GD 04)
文摘Electrode materials have an important effect on the property of microbial fuel cell(MFC). Carbon foam is utilized as an anode and further modified by urea to improve its performance in marine benthic microbial fuel cell(BMFC) with higher voltage and output power. The electrochemical properties of plain carbon foam(PC) and urea-modified carbon foam(UC) are measured respectively. Results show that the UC obtains better wettability after its modification and higher anti-polarization ability than the PC. A novel phenomenon has been found that the electrical potential of the modified UC anode is nearly 100 m V lower than that of the PC, reaching-570 ±10 m V(vs. SCE), and that it also has a much higher electron transfer kinetic activity, reaching 9399.4 m W m-2, which is 566.2-fold higher than that from plain graphite anode(PG). The fuel cell containing the UC anode has the maximum power density(256.0 m W m-2) among the three different BMFCs. Urea would enhance the bacteria biofilm formation with a more diverse microbial community and maintain more electrons, leading to a lower anodic redox potential and higher power output. The paper primarily analyzes why the electrical potential of the modified anode becomes much lower than that of others after urea modification. These results can be utilized to construct a novel BMFC with higher output power and to design the conditioner of voltage booster with a higher conversion ratio. Finally, the carbon foam with a bigger pore size would be a potential anodic material in conventional MFC.
文摘In this paper, a close relationship between the intraseasonal variation of subtropical high over East Asia and the convective activities around the South China Sea and the Philippines is analysed from OLR data.This relationship is studied by using the theory of wave propagating in a slowly varying medium and by using a quasi-geoslrophic, linear, spherical model and the IAP-GCM, respectively. The results show that when the SST is warming around the western tropical Pacific or the Philippines, the convective activities are intensified around the Philippines. As a consequence, the subtropical high will be intensified over East Asia. The computed results also show that when the anomaly of convective activities are caused around the Philippines, a teleconnection pattern of circulation anomalies will be caused over South Asia, East Asia and North America.
文摘Objectives： The study assessed if the level of knowledge of HIV-infected about HAART and waiting-times in the PHC （primary healthcare） clinic have an influence on antiretroviral adherence. Methods： A descriptive-cross-sectional study was conducted in South Africa. Data collected uses a standardized-questionnaire and face-to-face-exit interviews. Pill-count technique was performed and a value of≥ 95% acceptable. Data were analysed using SPSS. Univariate-factors associated with poor-adherence to knowledge about HAART and waiting times were assessed using ANOVA and p ≤ 0.05 considered statistically significant. Key findings： Of 86 enrolled, 63（73.3%） were females and 23（26.7%） males, with mean-age （± SD） of 35.6（±9.6） years and on HAART for 35.5（± 31.8） months ranging from 1-137. Of these, 27（31.40%） and 25（29.07%） were on WHO stages 2 and 3 respectively. Adherence-rates computed from 32 patients, 23（71.9%） revealed poor adherence-rates. The level of knowledge about HAART in terms of names of tablets, correct-dose, frequency, adverse-effects had no influence on ARV-adherence （p _〉 0.05）. Of 23 non-compliant, 10 （40%） gave the reason of drugs-unavailability, 7（30%） adverse-effects, 5（20%） drugs＇ complexity, and 1（10%） too busy to take them. Waiting areas associated with poor ARV-adherence were reception （p = 0.028）, doctors （p = 0.027）, while nurse＇s station （p = 0.29） and pharmacy （p = 0.43） revealed acceptable ARV-adherence.
基金supported by the National Eye Institute/National Institutes of Health core grant P30-EY06360(Department of Ophthalmology,Emory University School of Medicine)National Eye Institute,National Institutes of Health R01 EY029594(Yeh)and K23 EY030158(Shantha)+1 种基金Funding support was also provided via an Unrestricted Grant from Research to Prevent Blindness(Emory Eye Center,Emory University School of Medicine)Research support has also been provided by the Association for Research in Vision and Ophthalmology Mallinckrodt Award and the Stanley M.Truhlsen Family Foundation,Inc.
文摘Cytomegalovirus(CMV)retinitis is an opportunistic infection that has traditionally affected those who have HIV/AIDS or immunosuppressed individuals.CMV retinitis previously infected one-third of AIDS patients in the pre-highly active antiretroviral therapy(HAART)era,but since HAART,Western countries have seen an 80%decrease in the incidence of the disease.More recently,CMV retinitis has been reported in patients who are immunosuppressed,often due to chemotherapy or immunomodulatory medications.The diagnosis of CMV retinitis is often suspected based on clinical findings,with polymerase chain reaction for confirmation of CMV,especially in atypical cases.Highly active antiretroviral therapy and anti-CMV medications(systemic or local)remain the mainstay of treatment.However,for those who are not responsive to HAART,CMV retinitis remains a challenge,and can still lead to significant vision loss.Moreover,a regimen of anti-CMV medications can sometimes lead to viral resistance or organ toxicity.Complications such as immune recovery retinitis and rhegmatogenous retinal detachments continue to threaten the vision of patients who develop CMV retinitis.These complications can arise following initiation of treatment or if patients show disease progression.Proper vision screening for CMV retinitis in immunosuppressed patients at-risk is necessary for early detection and treatment.
基金financially supported by the National Natural Science Foundation of China(Nos.91126021 and 21376210)Natural Science Foundation of Zhejiang Province(Nos.LY22B070003 and 2016R401088)。
文摘Soft N-donor bis-triazin bipyridines derives(R-BTBP)are a type of very promising extratant for extraction and complexation with long-lived trivalent minor actinides over lanthanides from highly active liquid waste(HLW).In addition to minor actinides,R-BTBP also holds very strong complexation ability toward fission palladium.However,few studies have been focused on the separation and complexation with the fission product Pd(Ⅱ)by R-BTBP.Herein,the complexation behaviors of Pd(Ⅱ)with four typical R-BTBP ligands were systematically studied by single crystal X-ray diffraction,1H NMR titration and theoretical calculation.The effects of R-BTBP initial conformation and nitrate anions on the complexation behaviors of R-BTBP with Pd(Ⅱ)were thoughtfully analyzed.Both the 1:1 and 2:1 binuclear complexes could be formed between Pd(Ⅱ)and R-BTBP with initialⅡconformation in the presence of nitrate anions,while only one 1:1 type Pd(Ⅱ)complex could be formed for those with initial OO conformation.Without nitrate anion,only one 1:1 type complex was formed in solution.The structure of the 1:1 Pd(Ⅱ)/R-BTBP complex was firstly characterized by single crystal crystallography.DFT calculation results showed that a significant large rotational energy barrier(21.8~22.6 kcal/mol)must be overcome to form theⅡtype 2:1Pd(Ⅱ)complex for those OO type R-BTBP ligands,however which would not prevent them from forming the 1:1 type complex.
