Ostreopsis cf.ovata is a marine benthic dinoflagellate in tropical and temperate seas and can produce potent toxic compounds.The existence of O.cf.ovata has been found in the Chinese coastal areas,but studies on its t...Ostreopsis cf.ovata is a marine benthic dinoflagellate in tropical and temperate seas and can produce potent toxic compounds.The existence of O.cf.ovata has been found in the Chinese coastal areas,but studies on its toxicity are very few.This study investigated the toxicity of the O.cf.ovata(TIO991)isolated from Weizhou Island in the South China Sea by using methanol and chloroform to extract toxic compounds from the algal cells cultured indoor.Experiments on mouse acute toxicity showed that the crude methanol extract(CME)of O.cf.ovata caused the death of mice in 16–18 min.Furthermore,CME inhibited the cell reproduction of human neuroblastoma cells(BE(2)-M17 cells)by Cell Counting Kit-8 with a dose-and time-effect relationship and caused cell death in the form of cell necrosis.We found that CME had strong hemolytic activity and was significantly inhibited by ouabain,indicating that CME might contain palytoxins.By contrast,the crude chloroform extract of O.cf.ovata was relatively weak in toxicity as obtained in our experiments on mouse acute toxicity,cytotoxicity,and hemolytic activity.This suggests that the algae may raise the potential threat to marine ecosystems and public health.展开更多
Two-step-processed(TSP)inverted p-i-n perovskite solar cells(PSCs)have demonstrated significant promise in tandem applications.However,the power conversion efficiency(PCE)of TSP p-i-n PSCs rarely exceeds 24%.Here,we d...Two-step-processed(TSP)inverted p-i-n perovskite solar cells(PSCs)have demonstrated significant promise in tandem applications.However,the power conversion efficiency(PCE)of TSP p-i-n PSCs rarely exceeds 24%.Here,we demonstrate that TSP perovskite films exhibit a vertically gradient distribution of residual PbI_(2)clusters,which form Schottky heterojunctions with the perovskite,leading to substantial interfacial energy-level mismatches within NiO_(x)-based TSP p-i-n PSCs.These limitations were effectively addressed via a vertical interfacial engineering enabled by dual-interface modification incorporating tin trifluoromethanesulfonate(Sn(OTF)_(2))and 4-Fluorophenylethylamine chloride(F-PEA)at the NiO_(x)/perovskite and perovskite/C60 interfaces,respectively.The functional Sn(OTF)_(2)not only enhances the conductivity of NiO_(x)films but also suppresses ion migration,while inducing the formation of a Pb-Sn mixed perovskite interlayer that precisely regulates the energy level at the NiO_(x)/perovskite interface.Complementally,F-PEA post-treatment effectively converts surface residual PbI_(2)clusters into a 2D perovskite capping layer,which simultaneously passivates surface defects and enhances energy-level alignment at the perovskite/C60 interface.Consequently,the optimized NiO_(x)-based TSP p-i-n PSCs achieve a notable PCE of 25.6%with superior operational stability.This study elucidates the underlying mechanisms limiting the efficiency of TSP p-i-n PSCs,while establishing design principles for these devices targeting 26%efficiency.展开更多
Bending is a crucial operation in the sheet forming of Mg alloys for automotive and aerospace applications.In this work,three kinds of sheets from an AZ31 rolled plate,sheared at 0°(S0),45°(S45),and 90°...Bending is a crucial operation in the sheet forming of Mg alloys for automotive and aerospace applications.In this work,three kinds of sheets from an AZ31 rolled plate,sheared at 0°(S0),45°(S45),and 90°(S90)to the rolling direction,were subjected to three-point bending tests.In-situ digital image correlation(DIC)system was employed to capture the strain fields.Electron backscatter diffraction(EBSD)was used to examine the through-thickness microstructures.A crystal plasticity finite element method(CPFEM)incorporating twinning and slip mechanisms was developed to simulate the bending deformation.The texture effect on the neutral layer shift and twinning behaviors was systematically investigated in terms of both experiments and simulations.The results show that CPFEM effectively simulated the texturedependent shifting behaviors of neutral layer and the associated twinning behaviors.Particularly,the spatial distributions of neutral layer across the entire bent plates were captured by both DIC and CPFEM.Additionally,some unusual twinning behaviors were analyzed in depth,such as the{10-12}-{10-12}secondary twins in S90,localized twin bands in S0,and the twin traces difference in S45.These findings reveal a close relationship between the neutral layer shift and twinning activity induced by the initial texture and strain levels.This work provides valuable insights into the bending deformation mechanisms of Mg alloys and has important implications for improving their formability and controlling springback.展开更多
Global land monsoon precipitation(GLMP)is highly sensitive to changes in interhemispheric thermal contrast(ITC).Amplified interhemispheric asymmetries of GLMP due to enhanced ITC driven by high-level anthropogenic emi...Global land monsoon precipitation(GLMP)is highly sensitive to changes in interhemispheric thermal contrast(ITC).Amplified interhemispheric asymmetries of GLMP due to enhanced ITC driven by high-level anthropogenic emissions are expected to simultaneously increase the probability of regional floods and droughts,threatening ecosystems within global terrestrial monsoon regions and the freshwater supply for billions of residents in these areas.In this study,the responses of GLMP to the evolution of ITC toward the carbon neutrality goal are assessed using multimodel outputs from a new model intercomparison project(CovidMIP).The results show that the Northern Hemisphere-Southern Hemisphere(NH-SH)asymmetry of GLMP in boreal summer weakens during the 2040s,as a persistent reduction in well-mixed greenhouse gas(WMGHG)emissions leads to a downward trend in the ITC after 2040.At the same time,the reduction in WMGHG emissions dampens the Eastern Hemisphere-Western Hemisphere(EH-WH)asymmetry of GLMP by inducing La Niña-like cooling and enhancing moisture transport to Inner America.The resulting increases in land monsoon precipitation(LMP)may alleviate drought under the global warming scenario by about 19%-25%and 7%-9%in the WH and SH monsoon regions,respectively.However,a persistent reduction in aerosol emissions in Asia will dominate the increases in LMP in this region until the mid-21st century,and these increases may be approximately 23%-60%of the growth under the global warming scenario.Our results highlight the different rates of response of aerosol and WMGHG concentrations to the carbon neutrality goal,leading to various changes in LMP at global and regional scales.展开更多
Electrocatalytic nitrate reduction reaction(NO3RR)represents a sustainable and environmentally benign route for ammonia(NH3)synthesis.However,NO3RR is still limited by the competition from hydrogen evolution reaction(...Electrocatalytic nitrate reduction reaction(NO3RR)represents a sustainable and environmentally benign route for ammonia(NH3)synthesis.However,NO3RR is still limited by the competition from hydrogen evolution reaction(HER)and the high energy barrier in the hydrogenation step of nitrogen-containing intermediates.Here,we report a selective etching strategy to construct Ru M nanoalloys(M=Fe,Co,Ni,Cu)uniformly dispersed on porous nitrogen-doped carbon substrates for efficient neutral NH3electrosynthesis.Density functional theory calculations confirm that the synergic effect between Ru and transition metal M modulates the electronic structure of the alloy,significantly lowering the energy barrier for the conversion of*NO_(2)to*HNO_(2).Experimentally,the optimized Ru Fe-NC catalyst achieves 100%Faraday efficiency with a high yield rate of 0.83 mg h^(-1)mg^(-1)catat a low potential of-0.1 V vs.RHE,outperforming most reported catalysts.In situ spectroscopic analyses further demonstrate that the Ru M-NC effectively promotes the hydrogenation of nitrogen intermediates while inhibiting the formation of hydrogen radicals,thereby reducing HER competition.The Ru FeNC assembled Zn-NO_(3)^(-)battery achieved a high open-circuit voltage and an outstanding power density and capacity,which drive selective NO_(3)^(-)conversion to NH3.This work provides a powerful synergistic design strategy for efficient NH3electrosynthesis and a general framework for the development of advanced multi-component catalysts for sustainable nitrogen conversion.展开更多
In order to survey the infectious situation of canine coronavirus (CCV) in giant panda population, a virus neutralization test detecting specific antibodies against CCV in giant panda抯 sera was established by using t...In order to survey the infectious situation of canine coronavirus (CCV) in giant panda population, a virus neutralization test detecting specific antibodies against CCV in giant panda抯 sera was established by using two-fold dilutions of serum and 100 TCID50 of the virus. The 62 sera samples of giant pandas, which were gathered from zoos and reserve region of Sichuan Province, China were detected. The neutralization antibody titer of 1:4 was recognized as the positive criterion, 8 sera samples were detected to be positive, and the positive rate was 12.9%. The titers of neutralizing antibody ranged from 1:8 to 1:32. It was the first comprehensive investigation on neutralization antibodies against CCV in giant panda population in China. The results of study showed that the infection of CCV in giant panda population was universal, which has posed a threat to the health of giant panda. Therefore, it is incumbent on us to study safe and effective vaccines to protect giant panda against CCV infection.展开更多
Selective recovery of scandium and titanium from red mud leaching solution was achieved through neutralization precipitation followed by acid leaching approach.In the neutralization precipitation section,the effects o...Selective recovery of scandium and titanium from red mud leaching solution was achieved through neutralization precipitation followed by acid leaching approach.In the neutralization precipitation section,the effects of pH,temperature and reaction time on metal precipitation efficiency were investigated.Under the optimal co ndition,the precipitation efficiencies of scandium and titanium were 93.74%and 99.47%,respectively.In the acid leaching section,the effects of acidity,temperature,reaction time,and raffinate to acid solution ratio on leaching efficiency were investigated.Under the optimal condition,the leaching efficiencies of scandium and titanium were 99.97%and 5.44%,respectively.The loss of scandium and titanium were 6.3%and 5.9%,respectively.Compared with the traditional extraction procedure of scandium in red mud,this method could separate titanium from scandium effectively,which is beneficial for the purification of the products and improvement of value of the metal.展开更多
To achieve the neutralization control requirements of the radio-frequency(RF)ion microthruster(μRIT)in the‘Taiji-1’satellite mission,we proposed an active neutralization control solution that is based on the carbon...To achieve the neutralization control requirements of the radio-frequency(RF)ion microthruster(μRIT)in the‘Taiji-1’satellite mission,we proposed an active neutralization control solution that is based on the carbon nanotube field emission technology.The carbon nanotube field emission neutralizer(CNTN)has the characteristics of light weight,small size,and propellantless,which is especially suitable for the neutralization control tasks of ion microthrusters.The Institute of Mechanics,Chinese Academy of Sciences,in collaboration with Tsinghua University,has successfully developed a CNTN to meet mission requirements.On the ground,the feasibility of cooperation working betweenμRIT and CNTN was fully verified,as well as the simulation and experimental study of neutralization control strategy,which finally passed the engineering assessment test.Since the launch of‘Taiji-1’satellite on 31 August,2019,the RF ion micropropulsion system has successfully completed nearly one hundred test missions in space.The test results indicate that CNTN does not have performance degradation,and the neutralization control strategy is effective.展开更多
On October 13,2020,on the fairway connecting the Polish Baltic ports ofSwinoujscie and Szczecin,an underwater hazardous object of historical origin in the form of the British deep penetration bomb Tallboy dropped duri...On October 13,2020,on the fairway connecting the Polish Baltic ports ofSwinoujscie and Szczecin,an underwater hazardous object of historical origin in the form of the British deep penetration bomb Tallboy dropped during the bombing of the German cruiser"Lützow"in April 1945 was neutralized successfully.It is believed to be the first underwater action concerning this type of bomb,which has previously been neutralized on land in Europe(Germany,one confirmed case).The preparation of the operation,on an unprecedented scale at national,European and global level,took one year and included a series of projects related to clearing the space around the bomb from other identified UXO objects,international consultations,historical analyses,determination of the risk to residents and critical infrastructure in the event of an explosion of the bomb containing approximately 2400 kg of the TORPEX explosive(with an increased force equivalent to almost 3600 kg of TNT).The object was neutralized on spot at the depth of 12 m,near a ferry crossing,by specialists from the 41st Navy EOD Team from the 12th MCM Squadron(8th Coastal Defence Flotilla),using the Low Order Deflagration technique(underwater deflagration method).In the case discussed,there was an accumulation of unfavourable conditions which practically excluded the use of blow-in-situ explosive methods(BIP),as well as the extraction of the object and its transport to a military ground.After a partial deflagration of the explosive,the explosive was detonated(DDT).Estimates indicate that the deflagration level reached between 55 and 60%,which significantly reduced the strength and effects of the underwater explosion.展开更多
This paper analyzed the current situation and development trends of energy consumption and carbon emissions,and the current situation and development trend of coal consumption in China.In the context of recently estab...This paper analyzed the current situation and development trends of energy consumption and carbon emissions,and the current situation and development trend of coal consumption in China.In the context of recently established carbon peak and carbon neutralization targets,this paper put forward the main problems associated with the green and low-carbon development and utilization of coal.Five key technological innovation directions in mining were proposed,including green coal development,intelligent and efficient mining,low-carbon utilization and conversion of coal,energy conservation and emission reduction,carbon capture,utilization and storage(CCUS).Focusing on the above technological innovation directions,it is suggested to carry out three basic theories,including the theory of green efficient intelligent mining,clean and low-carbon utilization and transformation of coal,and CCUS.Meanwhile,it is proposed to develop 12 key technologies,including green coal mining and ecological environment protection,efficient coal mining and intelligent mine construction,key technologies and equipment for efficient coal processing,underground coal gasification and mining,ultra-high parameter and ultra-supercritical power generation technology,intelligent and flexible coal-fired power generation technology,new power cycle coal-fired power generation technology,the development of coal-based special fuels,coal-based bulk and specialty chemicals,energy conservation and consumption reduction,large-scale and low-cost carbon capture,CO_(2) utilization and storage.Finally,necessary measures from the governmental perspective were also proposed.展开更多
The CD4 binding site(CD4bs) of envelope glycoprotein(Env) is an important conserved target for anti-human immunodeficiency virus type 1(HIV-1) neutralizing antibodies. Neutralizing monoclonal antibodies IgG1 b12(b12) ...The CD4 binding site(CD4bs) of envelope glycoprotein(Env) is an important conserved target for anti-human immunodeficiency virus type 1(HIV-1) neutralizing antibodies. Neutralizing monoclonal antibodies IgG1 b12(b12) could recognize conformational epitopes that overlap the CD4 bs of Env. Different virus strains, even derived from the same individual, showed distinct neutralization susceptibility to b12. We examined the key amino acid residues affecting b12 neutralization susceptibility using single genome amplification and pseudovirus neutralization assay. Eleven amino acid residues were identified that affect the sensitivity of Env to b12. Through site-directed mutagenesis, an amino acid substitution at position 182 in the V2 region of Env was confirmed to play a key role in regulating the b12 neutralization susceptibility. The introduction of V182 L to a resistant strain enhanced its sensitivity to b12 more than twofold. Correspondingly, the introduction of L182 V to a sensitive strain reduced its sensitivity to b12 more than tenfold. Amino acid substitution at positions 267 and 346 could both enhance the sensitivity to b12 more than twofold. However, no additive effect was observed when the three site mutageneses were introduced into the same strain, and the sensitivity was equivalent to the single V182 L mutation. CRF07_BC is a major circulating recombinant form of HIV-1 prevalent in China. Our data may provide important information for understanding the molecular mechanism regulating the neutralization susceptibility of CRF07_BC viruses to b12 and may be helpful for a vaccine design targeting the CD4 bs epitopes.展开更多
The neutralizing activities of eight monoclonal antibodies （MAbs） against white spot syndrome virus （WSSV） （2D2, 2B2,1D2, 1D5, 1C2, 4A1, 6A4 and 6B4） were analyzed by in vivo experiments. Gills from WSSV-infecte...The neutralizing activities of eight monoclonal antibodies （MAbs） against white spot syndrome virus （WSSV） （2D2, 2B2,1D2, 1D5, 1C2, 4A1, 6A4 and 6B4） were analyzed by in vivo experiments. Gills from WSSV-infected shrimp were homogenized and ten-fold serially diluted by PBS, and then incubated with MAbs （hybridoma culture supernatant）, respectively. The mixture of WSSV and MAbs were injected into crayfish （Procambarus clarkii）. After challenge, the death rates of crayfish were counted to determine the neutralizing activities of MAbs. At the same time, the mixture of myeloma culture supernatant and WSSV or PBS was served as positive or negative control, respectively. The results showed that, at each virus dilution, the mean time to death of the crayfish injected with MAb-treated virus was significantly longer than that in the positive control, though they all showed 100% mortality within 25 d, and meanwhile, few crayfish died in the negative control. Among the eight MAbs, 2D2, 2B2, 1D2 and 1D5, especially the former two, delayed the mortality significantly, and 1 C2, 4A1 and 6A4 delayed the mortality as well but not so efficiently, while MAb 6IM was efficient only when the virus concentration increased. The results indicated that the anti-WSSV MAbs can neutralize WSSV in different virus dilutions.展开更多
This study described a regime map for dry neutralization agglomeration. Based on the map, the effects of selected key parameters, such as ingredient composition, operation temperature, agitation speed, and size of Na_...This study described a regime map for dry neutralization agglomeration. Based on the map, the effects of selected key parameters, such as ingredient composition, operation temperature, agitation speed, and size of Na_2CO_3 particles, were investigated using a laboratory-scale mixer, and properties of the agglomeration product were analyzed, including particle size distribution, Hunter color, and flowability. Torque curves evolving during the process were correlated with the system flowability. Three distinguishable regimes were indicated, dry, wet, and transitional, and the agitation speed was found to have a different influence on the agglomeration process for the three regimes. Furthermore, the influence of temperature on reactive agglomeration significantly differed from that in agglomeration processes in which the binder was non-reactive.展开更多
Bauxite residues,a large volume solid waste,are in urgent need of effective disposal and management.Especially,strategies to alleviate the high alkalinity of bauxite residue remain a big challenge.Here,we developed a ...Bauxite residues,a large volume solid waste,are in urgent need of effective disposal and management.Especially,strategies to alleviate the high alkalinity of bauxite residue remain a big challenge.Here,we developed a synergistic pyrolysis to neutralize the alkalinity of bauxite residue and upgrade the structure of biomass simultaneously.By cooperating the catalytic feature from bauxite residue,rice straw,a cellulose-enriched biomass,could prefer to produce acidic components under a hypothermal pyrolysis temperature(below 250℃)and partial oxygen-contained atmosphere as evidenced by the synchronous TGA-FTIR analysis.In return,these in-situ produced acidic components neutralized the bauxite residue profoundly(pH decreased from 11.5 to 7.2)to obtain a neutral product with long-term water leaching stability.Also,a higher pyrolysis temperature led to neutral biochar-based products with well-defined carbonization characteristics.Thus,the biomass-driven pyrolysis strategy provides a potential to dispose the alkalinity issue of bauxite residue and further opportunities for the sustainable reuse and continuing management of bauxite residue.展开更多
Control of pH neutralization processes is challenging in the chemical process industry because of their inherent strong nonlinearity. In this paper, the model algorithmic control (MAC) strategy is extended to nonlinea...Control of pH neutralization processes is challenging in the chemical process industry because of their inherent strong nonlinearity. In this paper, the model algorithmic control (MAC) strategy is extended to nonlinear processes using Hammerstein model that consists of a static nonlinear polynomial function followed in series by a linear impulse response dynamic element. A new nonlinear Hammerstein MAC algorithm (named NLH-MAC) is presented in detail. The simulation control results of a pH neutralization process show that NLH-MAC gives better control performance than linear MAC and the commonly used industrial nonlinear propotional plus integral plus derivative (PID) controller. Further simulation experiment demonstrates that NLH-MAC not only gives good control response, but also possesses good stability and robustness even with large modeling errors.展开更多
Bauxite residue deposit area(BRDA)is a typical abandoned mining wasteland representing extreme hostile environment with increased alkalinity.Microbially-driven neutralization of bauxite residue,based on the microbial ...Bauxite residue deposit area(BRDA)is a typical abandoned mining wasteland representing extreme hostile environment with increased alkalinity.Microbially-driven neutralization of bauxite residue,based on the microbial acid producing metabolisms,is a novel strategy for achieving rapid pH neutralization and thus improving its environmental outcomes.The hypothesis was that these extreme conditions promote microbial communities which are capable of novel ecologically relevant functions.Several alkaliphilic acid producing bacteria were isolated in this study.One strain was selected for its superior growth pattern and acid metabolism(termed EEEL02).Based on the phylogenetic analysis,this strain was identified as Bacillus thuringiensis.The optimized fermentation conditions were as follows:pH 10;NaCl concentration 5%;temperature 25℃;EEEL02 preferred glucose and peptone as carbon and nitrogen sources,respectively.Based on optimal fermentation conditions,EEEL02 induced a significant pH reduction from 10.26 to 5.62 in 5-day incubation test.Acetic acid,propionic acid and CO_(2)(g)were the major acid metabolites of fermentation,suggesting that the pH reduction in bauxite residue may be caused by acid neutralization derived from microbial metabolism.This finding provided the basis of a novel strategy for achieving rapid pH neutralization of bauxite residue.展开更多
Objective Although HIV-1 infection is prevalent in many regions in China, it remains largely unknown on the biological characteristics of dominant circulating isolates. This study was designed to isolate the circulati...Objective Although HIV-1 infection is prevalent in many regions in China, it remains largely unknown on the biological characteristics of dominant circulating isolates. This study was designed to isolate the circulating viral strains from different prevalent regions and to characterize their biological properties and neutralization sensitivity. Methods Primary viruses were isolated from fresh PBMCs using the traditional co-culture method and their capacity of inducing syncytium was tested in MT-2 cells. Meanwhile, their coreceptor usage was determined with two cell lines: Magi and GHOST (3) stably expressing CD4 and the chemokine receptor CCR5 or CXCR4. Furthermore, the sensitivity of these viruses to neutralization by HIV-1-infected patients’ plasma which were highly active to neutralize SF33 strain, was quantified in GHOST cell-based neutralization assay. Results Six primary viral strains were isolated from 4 separated regions. Isolates LTG0213,LTG0214 and XVS032691 induced syncytia in MT-2 cells, and used CXCR4 as coreceptor. Isolates XJN0021, XJN0091, or SHXDC0041 did not induce syncytia, and used CCR5 as coreceptor. Overall neutralization sensitivity differed among four representative strains: HIV-1 XVS032691>LTG0214>XJN0091≈SHXDC0041. Conclusion The neutralization sensitivity of HIV isolates is linked with the phenotype of isolates, in which syncytium-inducing (SI) or CXCR4-tropic (X4) viruses are more easily neutralized than non-syncytium-inducing (NSI) or CCR5-tropic (R5) viruses. The genetic subtypes based on the phylogeny of env sequences are not classical neutralization serotypes.展开更多
An electron cyclotron resonance ion thruster must emit an electron current equivalent to its ion beam current to prevent the thruster system from being electrically charged. This operation is defined as neutralization...An electron cyclotron resonance ion thruster must emit an electron current equivalent to its ion beam current to prevent the thruster system from being electrically charged. This operation is defined as neutralization. The factors which influence neutralization are categorized into the ion beam current parameters, the neutralizer input parameters, and the neutralizer position. To understand the mechanism of neutralization, an experiment and a calculation study on how these factors influence thruster neutralization are presented. The experiment results show that the minimum bias voltage of the neutralizer was -60 V at the ion beam current of 80 mA for the argon propellant, and a critical gas flow rate existed, below which the coupling voltage increased sharply. Based on the experiment, the neutralization was analyzed by means of a onedimensional calculation model. The computation results show that the coupling voltage was influenced by the beam divergence and the negative potential zone near the grids.展开更多
Completely weathered phyllite(CWP)soil is a kind of special soil with high swell potential,while red clay is a special soil with high shrinkage.This means that these two kinds of special soils are usually not suitable...Completely weathered phyllite(CWP)soil is a kind of special soil with high swell potential,while red clay is a special soil with high shrinkage.This means that these two kinds of special soils are usually not suitable for direct use as subgrade fill.To reduce the swell index of the CWP soil and the shrinkage of red clay at the same time,it was proposed to blend the CWP soil with red clay to improve their basic characteristics.A series of swell index tests and dry-wet cycle tests of the blended soils have been carried out at varying blending ratios,compaction coefficients and moisture contents.The test results show that the free swell index of the blended soil decreases with the increase of red clay,moisture content and compaction coefficient,respectively.The fissure density of the blended soil first decreases and then increases with the blending ratio,with the lowest being zero when the blending ratio is ranging from 20%to 40%.Through particle microscopic analysis and elemental composition analysis,it is found that the neutralization effect,the dilution effect of swell minerals,and the partition effect of coarse particles play an important role in restraining expansion and shrinkage deformation of the blended soil.Based on the liquid limit requirement of Chinese Railway Design Code(TB 10001-2016),the optimal blending ratio of red clay has been proposed to be 50%.Compared with the CWP soil,the free load swell index of the blended soil is reduced by 45.0%and the fissure density is reduced by 99.3%compared with that of red clay.Therefore,it is feasible to improve the CWP soil by blending it with red clay at an optimal ratio of 50%by using the neutralization effect of the expansion of CWP and shrinkage of red clay.展开更多
The Hantaan virus(HTNV)and Seoul virus(SEOV)mutants have accumulated over time.It is important to determine whether their neutralizing epitopes have evolved,thereby making the current vaccine powerless.However,it is i...The Hantaan virus(HTNV)and Seoul virus(SEOV)mutants have accumulated over time.It is important to determine whether their neutralizing epitopes have evolved,thereby making the current vaccine powerless.However,it is impossible to determine by using traditional plaque reduction neutralization test(PRNT),because it requires large numbers of live mutant strains.Pseudovirus-based neutralization assays(PBNA)were developed by employing vesicular stomatitis virus(VSV)backbone incorporated with HTNV or SEOV glycoproteins(VSVDG*-HTNVG or VSVDG*-SEOVG).56 and 51 single amino acid substitutions of glycoprotein(GP)in HTNV and SEOV were selected and introduced into the reference plasmid.Then the mutant pseudoviruses were generated and tested by PBNA.The PBNA results were highly correlated with PRNT ones with R2 being 0.91 for VSVDG*-HTNVG and 0.82 for VSVDG*-SEOVG.53 HTNV mutant pseudoviruses and 46 SEOV mutants were successfully generated.Importantly,by using PBNA,we found that HTNV or SEOV immunized antisera could neutralize all the corresponding 53 HTNV mutants or the 46 SEOV mutants respectively.The novel PBNA enables us to closely monitor the effectiveness of vaccines against large numbers of evolving HTNV and SEOV.And the current vaccine remains to be effective for the naturally occurring mutants.展开更多
基金Supported by the Special Research for the Science and Technology Basic Resources Investigation Program of China(No.2018FY100200)the National Natural Science Foundation of China(No.42176206)the Natural Science Foundation of Shandong Province(No.ZR2021MD071)。
文摘Ostreopsis cf.ovata is a marine benthic dinoflagellate in tropical and temperate seas and can produce potent toxic compounds.The existence of O.cf.ovata has been found in the Chinese coastal areas,but studies on its toxicity are very few.This study investigated the toxicity of the O.cf.ovata(TIO991)isolated from Weizhou Island in the South China Sea by using methanol and chloroform to extract toxic compounds from the algal cells cultured indoor.Experiments on mouse acute toxicity showed that the crude methanol extract(CME)of O.cf.ovata caused the death of mice in 16–18 min.Furthermore,CME inhibited the cell reproduction of human neuroblastoma cells(BE(2)-M17 cells)by Cell Counting Kit-8 with a dose-and time-effect relationship and caused cell death in the form of cell necrosis.We found that CME had strong hemolytic activity and was significantly inhibited by ouabain,indicating that CME might contain palytoxins.By contrast,the crude chloroform extract of O.cf.ovata was relatively weak in toxicity as obtained in our experiments on mouse acute toxicity,cytotoxicity,and hemolytic activity.This suggests that the algae may raise the potential threat to marine ecosystems and public health.
基金financially supported by the National Nature Science Foundation of China (62504130)National Key Research and Development Program of China (2018YFB0704100)+3 种基金the Key university laboratory of highly efficient utilization of solar energy and sustainable development of Guangdong (Y01256331)the Technology Development Project of Henan Province (252102240047)the Pico Center at SUSTech CRF which receives support from the Presidential FundDevelopment and Reform Commission of Shenzhen Municipality
文摘Two-step-processed(TSP)inverted p-i-n perovskite solar cells(PSCs)have demonstrated significant promise in tandem applications.However,the power conversion efficiency(PCE)of TSP p-i-n PSCs rarely exceeds 24%.Here,we demonstrate that TSP perovskite films exhibit a vertically gradient distribution of residual PbI_(2)clusters,which form Schottky heterojunctions with the perovskite,leading to substantial interfacial energy-level mismatches within NiO_(x)-based TSP p-i-n PSCs.These limitations were effectively addressed via a vertical interfacial engineering enabled by dual-interface modification incorporating tin trifluoromethanesulfonate(Sn(OTF)_(2))and 4-Fluorophenylethylamine chloride(F-PEA)at the NiO_(x)/perovskite and perovskite/C60 interfaces,respectively.The functional Sn(OTF)_(2)not only enhances the conductivity of NiO_(x)films but also suppresses ion migration,while inducing the formation of a Pb-Sn mixed perovskite interlayer that precisely regulates the energy level at the NiO_(x)/perovskite interface.Complementally,F-PEA post-treatment effectively converts surface residual PbI_(2)clusters into a 2D perovskite capping layer,which simultaneously passivates surface defects and enhances energy-level alignment at the perovskite/C60 interface.Consequently,the optimized NiO_(x)-based TSP p-i-n PSCs achieve a notable PCE of 25.6%with superior operational stability.This study elucidates the underlying mechanisms limiting the efficiency of TSP p-i-n PSCs,while establishing design principles for these devices targeting 26%efficiency.
基金supported by the National Natural Science Foundation of China(No.52371004,52201144,52071040,U20A20230).
文摘Bending is a crucial operation in the sheet forming of Mg alloys for automotive and aerospace applications.In this work,three kinds of sheets from an AZ31 rolled plate,sheared at 0°(S0),45°(S45),and 90°(S90)to the rolling direction,were subjected to three-point bending tests.In-situ digital image correlation(DIC)system was employed to capture the strain fields.Electron backscatter diffraction(EBSD)was used to examine the through-thickness microstructures.A crystal plasticity finite element method(CPFEM)incorporating twinning and slip mechanisms was developed to simulate the bending deformation.The texture effect on the neutral layer shift and twinning behaviors was systematically investigated in terms of both experiments and simulations.The results show that CPFEM effectively simulated the texturedependent shifting behaviors of neutral layer and the associated twinning behaviors.Particularly,the spatial distributions of neutral layer across the entire bent plates were captured by both DIC and CPFEM.Additionally,some unusual twinning behaviors were analyzed in depth,such as the{10-12}-{10-12}secondary twins in S90,localized twin bands in S0,and the twin traces difference in S45.These findings reveal a close relationship between the neutral layer shift and twinning activity induced by the initial texture and strain levels.This work provides valuable insights into the bending deformation mechanisms of Mg alloys and has important implications for improving their formability and controlling springback.
基金funded by the National Natural Science Foundation of China(Grant No.42275039)the Meteorological Joint Fund by NSF and CMA(Grant No.U2342224)+1 种基金the National Key R&D Program of China(Grant No.2022YFC3701202)the S&T Development Fund of CAMS(Grant No.2024KJ019)。
文摘Global land monsoon precipitation(GLMP)is highly sensitive to changes in interhemispheric thermal contrast(ITC).Amplified interhemispheric asymmetries of GLMP due to enhanced ITC driven by high-level anthropogenic emissions are expected to simultaneously increase the probability of regional floods and droughts,threatening ecosystems within global terrestrial monsoon regions and the freshwater supply for billions of residents in these areas.In this study,the responses of GLMP to the evolution of ITC toward the carbon neutrality goal are assessed using multimodel outputs from a new model intercomparison project(CovidMIP).The results show that the Northern Hemisphere-Southern Hemisphere(NH-SH)asymmetry of GLMP in boreal summer weakens during the 2040s,as a persistent reduction in well-mixed greenhouse gas(WMGHG)emissions leads to a downward trend in the ITC after 2040.At the same time,the reduction in WMGHG emissions dampens the Eastern Hemisphere-Western Hemisphere(EH-WH)asymmetry of GLMP by inducing La Niña-like cooling and enhancing moisture transport to Inner America.The resulting increases in land monsoon precipitation(LMP)may alleviate drought under the global warming scenario by about 19%-25%and 7%-9%in the WH and SH monsoon regions,respectively.However,a persistent reduction in aerosol emissions in Asia will dominate the increases in LMP in this region until the mid-21st century,and these increases may be approximately 23%-60%of the growth under the global warming scenario.Our results highlight the different rates of response of aerosol and WMGHG concentrations to the carbon neutrality goal,leading to various changes in LMP at global and regional scales.
基金financially supported by National Natural Science Foundation of China(22466010)Guizhou Provincial Basic Research Program(Natural Science)ZK[2023]47 and key program ZD[2025]075+6 种基金Innovation and Entrepreneurship Project for overseas Talents in Guizhou Province[2022]02Specific Natural Science Foundation of Guizhou University(X202207)the national undergraduate innovation and entrepreneurship training program(gzugc2023006gzusc2024012)SRT project of Guizhou university(2023SRT0292023SRT024)supported by Shanghai Technical Service Center of Science and Engineering Computing,Shanghai University。
文摘Electrocatalytic nitrate reduction reaction(NO3RR)represents a sustainable and environmentally benign route for ammonia(NH3)synthesis.However,NO3RR is still limited by the competition from hydrogen evolution reaction(HER)and the high energy barrier in the hydrogenation step of nitrogen-containing intermediates.Here,we report a selective etching strategy to construct Ru M nanoalloys(M=Fe,Co,Ni,Cu)uniformly dispersed on porous nitrogen-doped carbon substrates for efficient neutral NH3electrosynthesis.Density functional theory calculations confirm that the synergic effect between Ru and transition metal M modulates the electronic structure of the alloy,significantly lowering the energy barrier for the conversion of*NO_(2)to*HNO_(2).Experimentally,the optimized Ru Fe-NC catalyst achieves 100%Faraday efficiency with a high yield rate of 0.83 mg h^(-1)mg^(-1)catat a low potential of-0.1 V vs.RHE,outperforming most reported catalysts.In situ spectroscopic analyses further demonstrate that the Ru M-NC effectively promotes the hydrogenation of nitrogen intermediates while inhibiting the formation of hydrogen radicals,thereby reducing HER competition.The Ru FeNC assembled Zn-NO_(3)^(-)battery achieved a high open-circuit voltage and an outstanding power density and capacity,which drive selective NO_(3)^(-)conversion to NH3.This work provides a powerful synergistic design strategy for efficient NH3electrosynthesis and a general framework for the development of advanced multi-component catalysts for sustainable nitrogen conversion.
基金This research was supported by National Science Founda-tion of China (No. 30000123) and Conversation Department of Wildlife Ani-mal & Plants of State Forestry Bureau.
文摘In order to survey the infectious situation of canine coronavirus (CCV) in giant panda population, a virus neutralization test detecting specific antibodies against CCV in giant panda抯 sera was established by using two-fold dilutions of serum and 100 TCID50 of the virus. The 62 sera samples of giant pandas, which were gathered from zoos and reserve region of Sichuan Province, China were detected. The neutralization antibody titer of 1:4 was recognized as the positive criterion, 8 sera samples were detected to be positive, and the positive rate was 12.9%. The titers of neutralizing antibody ranged from 1:8 to 1:32. It was the first comprehensive investigation on neutralization antibodies against CCV in giant panda population in China. The results of study showed that the infection of CCV in giant panda population was universal, which has posed a threat to the health of giant panda. Therefore, it is incumbent on us to study safe and effective vaccines to protect giant panda against CCV infection.
基金Project supported by the National Natural Science Foundation of China(21707167)。
文摘Selective recovery of scandium and titanium from red mud leaching solution was achieved through neutralization precipitation followed by acid leaching approach.In the neutralization precipitation section,the effects of pH,temperature and reaction time on metal precipitation efficiency were investigated.Under the optimal co ndition,the precipitation efficiencies of scandium and titanium were 93.74%and 99.47%,respectively.In the acid leaching section,the effects of acidity,temperature,reaction time,and raffinate to acid solution ratio on leaching efficiency were investigated.Under the optimal condition,the leaching efficiencies of scandium and titanium were 99.97%and 5.44%,respectively.The loss of scandium and titanium were 6.3%and 5.9%,respectively.Compared with the traditional extraction procedure of scandium in red mud,this method could separate titanium from scandium effectively,which is beneficial for the purification of the products and improvement of value of the metal.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (Nos. XDB23030300, XDA1502070901, XDA1502070503)。
文摘To achieve the neutralization control requirements of the radio-frequency(RF)ion microthruster(μRIT)in the‘Taiji-1’satellite mission,we proposed an active neutralization control solution that is based on the carbon nanotube field emission technology.The carbon nanotube field emission neutralizer(CNTN)has the characteristics of light weight,small size,and propellantless,which is especially suitable for the neutralization control tasks of ion microthrusters.The Institute of Mechanics,Chinese Academy of Sciences,in collaboration with Tsinghua University,has successfully developed a CNTN to meet mission requirements.On the ground,the feasibility of cooperation working betweenμRIT and CNTN was fully verified,as well as the simulation and experimental study of neutralization control strategy,which finally passed the engineering assessment test.Since the launch of‘Taiji-1’satellite on 31 August,2019,the RF ion micropropulsion system has successfully completed nearly one hundred test missions in space.The test results indicate that CNTN does not have performance degradation,and the neutralization control strategy is effective.
文摘On October 13,2020,on the fairway connecting the Polish Baltic ports ofSwinoujscie and Szczecin,an underwater hazardous object of historical origin in the form of the British deep penetration bomb Tallboy dropped during the bombing of the German cruiser"Lützow"in April 1945 was neutralized successfully.It is believed to be the first underwater action concerning this type of bomb,which has previously been neutralized on land in Europe(Germany,one confirmed case).The preparation of the operation,on an unprecedented scale at national,European and global level,took one year and included a series of projects related to clearing the space around the bomb from other identified UXO objects,international consultations,historical analyses,determination of the risk to residents and critical infrastructure in the event of an explosion of the bomb containing approximately 2400 kg of the TORPEX explosive(with an increased force equivalent to almost 3600 kg of TNT).The object was neutralized on spot at the depth of 12 m,near a ferry crossing,by specialists from the 41st Navy EOD Team from the 12th MCM Squadron(8th Coastal Defence Flotilla),using the Low Order Deflagration technique(underwater deflagration method).In the case discussed,there was an accumulation of unfavourable conditions which practically excluded the use of blow-in-situ explosive methods(BIP),as well as the extraction of the object and its transport to a military ground.After a partial deflagration of the explosive,the explosive was detonated(DDT).Estimates indicate that the deflagration level reached between 55 and 60%,which significantly reduced the strength and effects of the underwater explosion.
文摘This paper analyzed the current situation and development trends of energy consumption and carbon emissions,and the current situation and development trend of coal consumption in China.In the context of recently established carbon peak and carbon neutralization targets,this paper put forward the main problems associated with the green and low-carbon development and utilization of coal.Five key technological innovation directions in mining were proposed,including green coal development,intelligent and efficient mining,low-carbon utilization and conversion of coal,energy conservation and emission reduction,carbon capture,utilization and storage(CCUS).Focusing on the above technological innovation directions,it is suggested to carry out three basic theories,including the theory of green efficient intelligent mining,clean and low-carbon utilization and transformation of coal,and CCUS.Meanwhile,it is proposed to develop 12 key technologies,including green coal mining and ecological environment protection,efficient coal mining and intelligent mine construction,key technologies and equipment for efficient coal processing,underground coal gasification and mining,ultra-high parameter and ultra-supercritical power generation technology,intelligent and flexible coal-fired power generation technology,new power cycle coal-fired power generation technology,the development of coal-based special fuels,coal-based bulk and specialty chemicals,energy conservation and consumption reduction,large-scale and low-cost carbon capture,CO_(2) utilization and storage.Finally,necessary measures from the governmental perspective were also proposed.
基金supported by grants from National Science and Technology Major Project(2012ZX10004701)
文摘The CD4 binding site(CD4bs) of envelope glycoprotein(Env) is an important conserved target for anti-human immunodeficiency virus type 1(HIV-1) neutralizing antibodies. Neutralizing monoclonal antibodies IgG1 b12(b12) could recognize conformational epitopes that overlap the CD4 bs of Env. Different virus strains, even derived from the same individual, showed distinct neutralization susceptibility to b12. We examined the key amino acid residues affecting b12 neutralization susceptibility using single genome amplification and pseudovirus neutralization assay. Eleven amino acid residues were identified that affect the sensitivity of Env to b12. Through site-directed mutagenesis, an amino acid substitution at position 182 in the V2 region of Env was confirmed to play a key role in regulating the b12 neutralization susceptibility. The introduction of V182 L to a resistant strain enhanced its sensitivity to b12 more than twofold. Correspondingly, the introduction of L182 V to a sensitive strain reduced its sensitivity to b12 more than tenfold. Amino acid substitution at positions 267 and 346 could both enhance the sensitivity to b12 more than twofold. However, no additive effect was observed when the three site mutageneses were introduced into the same strain, and the sensitivity was equivalent to the single V182 L mutation. CRF07_BC is a major circulating recombinant form of HIV-1 prevalent in China. Our data may provide important information for understanding the molecular mechanism regulating the neutralization susceptibility of CRF07_BC viruses to b12 and may be helpful for a vaccine design targeting the CD4 bs epitopes.
基金The National Basic Research Program of China under contract No 2006CB101806the National"863"Project of China under con-tract No 2006AA100312
文摘The neutralizing activities of eight monoclonal antibodies （MAbs） against white spot syndrome virus （WSSV） （2D2, 2B2,1D2, 1D5, 1C2, 4A1, 6A4 and 6B4） were analyzed by in vivo experiments. Gills from WSSV-infected shrimp were homogenized and ten-fold serially diluted by PBS, and then incubated with MAbs （hybridoma culture supernatant）, respectively. The mixture of WSSV and MAbs were injected into crayfish （Procambarus clarkii）. After challenge, the death rates of crayfish were counted to determine the neutralizing activities of MAbs. At the same time, the mixture of myeloma culture supernatant and WSSV or PBS was served as positive or negative control, respectively. The results showed that, at each virus dilution, the mean time to death of the crayfish injected with MAb-treated virus was significantly longer than that in the positive control, though they all showed 100% mortality within 25 d, and meanwhile, few crayfish died in the negative control. Among the eight MAbs, 2D2, 2B2, 1D2 and 1D5, especially the former two, delayed the mortality significantly, and 1 C2, 4A1 and 6A4 delayed the mortality as well but not so efficiently, while MAb 6IM was efficient only when the virus concentration increased. The results indicated that the anti-WSSV MAbs can neutralize WSSV in different virus dilutions.
文摘This study described a regime map for dry neutralization agglomeration. Based on the map, the effects of selected key parameters, such as ingredient composition, operation temperature, agitation speed, and size of Na_2CO_3 particles, were investigated using a laboratory-scale mixer, and properties of the agglomeration product were analyzed, including particle size distribution, Hunter color, and flowability. Torque curves evolving during the process were correlated with the system flowability. Three distinguishable regimes were indicated, dry, wet, and transitional, and the agitation speed was found to have a different influence on the agglomeration process for the three regimes. Furthermore, the influence of temperature on reactive agglomeration significantly differed from that in agglomeration processes in which the binder was non-reactive.
基金supported by the National Key Research and Development Program of China(No.2019YFC1803604)the National Natural Science Foundation of China(Nos.41877511+1 种基金21707135)the Fundamental Research Funds for the Central Universities of Central South University。
文摘Bauxite residues,a large volume solid waste,are in urgent need of effective disposal and management.Especially,strategies to alleviate the high alkalinity of bauxite residue remain a big challenge.Here,we developed a synergistic pyrolysis to neutralize the alkalinity of bauxite residue and upgrade the structure of biomass simultaneously.By cooperating the catalytic feature from bauxite residue,rice straw,a cellulose-enriched biomass,could prefer to produce acidic components under a hypothermal pyrolysis temperature(below 250℃)and partial oxygen-contained atmosphere as evidenced by the synchronous TGA-FTIR analysis.In return,these in-situ produced acidic components neutralized the bauxite residue profoundly(pH decreased from 11.5 to 7.2)to obtain a neutral product with long-term water leaching stability.Also,a higher pyrolysis temperature led to neutral biochar-based products with well-defined carbonization characteristics.Thus,the biomass-driven pyrolysis strategy provides a potential to dispose the alkalinity issue of bauxite residue and further opportunities for the sustainable reuse and continuing management of bauxite residue.
文摘Control of pH neutralization processes is challenging in the chemical process industry because of their inherent strong nonlinearity. In this paper, the model algorithmic control (MAC) strategy is extended to nonlinear processes using Hammerstein model that consists of a static nonlinear polynomial function followed in series by a linear impulse response dynamic element. A new nonlinear Hammerstein MAC algorithm (named NLH-MAC) is presented in detail. The simulation control results of a pH neutralization process show that NLH-MAC gives better control performance than linear MAC and the commonly used industrial nonlinear propotional plus integral plus derivative (PID) controller. Further simulation experiment demonstrates that NLH-MAC not only gives good control response, but also possesses good stability and robustness even with large modeling errors.
基金Projects(41877511,41842020)supported by the National Natural Science Foundation of ChinaProject(502221703)supported by the Innovative Project of Independent Exploration of Central South University,China
文摘Bauxite residue deposit area(BRDA)is a typical abandoned mining wasteland representing extreme hostile environment with increased alkalinity.Microbially-driven neutralization of bauxite residue,based on the microbial acid producing metabolisms,is a novel strategy for achieving rapid pH neutralization and thus improving its environmental outcomes.The hypothesis was that these extreme conditions promote microbial communities which are capable of novel ecologically relevant functions.Several alkaliphilic acid producing bacteria were isolated in this study.One strain was selected for its superior growth pattern and acid metabolism(termed EEEL02).Based on the phylogenetic analysis,this strain was identified as Bacillus thuringiensis.The optimized fermentation conditions were as follows:pH 10;NaCl concentration 5%;temperature 25℃;EEEL02 preferred glucose and peptone as carbon and nitrogen sources,respectively.Based on optimal fermentation conditions,EEEL02 induced a significant pH reduction from 10.26 to 5.62 in 5-day incubation test.Acetic acid,propionic acid and CO_(2)(g)were the major acid metabolites of fermentation,suggesting that the pH reduction in bauxite residue may be caused by acid neutralization derived from microbial metabolism.This finding provided the basis of a novel strategy for achieving rapid pH neutralization of bauxite residue.
文摘Objective Although HIV-1 infection is prevalent in many regions in China, it remains largely unknown on the biological characteristics of dominant circulating isolates. This study was designed to isolate the circulating viral strains from different prevalent regions and to characterize their biological properties and neutralization sensitivity. Methods Primary viruses were isolated from fresh PBMCs using the traditional co-culture method and their capacity of inducing syncytium was tested in MT-2 cells. Meanwhile, their coreceptor usage was determined with two cell lines: Magi and GHOST (3) stably expressing CD4 and the chemokine receptor CCR5 or CXCR4. Furthermore, the sensitivity of these viruses to neutralization by HIV-1-infected patients’ plasma which were highly active to neutralize SF33 strain, was quantified in GHOST cell-based neutralization assay. Results Six primary viral strains were isolated from 4 separated regions. Isolates LTG0213,LTG0214 and XVS032691 induced syncytia in MT-2 cells, and used CXCR4 as coreceptor. Isolates XJN0021, XJN0091, or SHXDC0041 did not induce syncytia, and used CCR5 as coreceptor. Overall neutralization sensitivity differed among four representative strains: HIV-1 XVS032691>LTG0214>XJN0091≈SHXDC0041. Conclusion The neutralization sensitivity of HIV isolates is linked with the phenotype of isolates, in which syncytium-inducing (SI) or CXCR4-tropic (X4) viruses are more easily neutralized than non-syncytium-inducing (NSI) or CCR5-tropic (R5) viruses. The genetic subtypes based on the phylogeny of env sequences are not classical neutralization serotypes.
基金support from National Natural Science Foundation of China (Grant No. 11475137)
文摘An electron cyclotron resonance ion thruster must emit an electron current equivalent to its ion beam current to prevent the thruster system from being electrically charged. This operation is defined as neutralization. The factors which influence neutralization are categorized into the ion beam current parameters, the neutralizer input parameters, and the neutralizer position. To understand the mechanism of neutralization, an experiment and a calculation study on how these factors influence thruster neutralization are presented. The experiment results show that the minimum bias voltage of the neutralizer was -60 V at the ion beam current of 80 mA for the argon propellant, and a critical gas flow rate existed, below which the coupling voltage increased sharply. Based on the experiment, the neutralization was analyzed by means of a onedimensional calculation model. The computation results show that the coupling voltage was influenced by the beam divergence and the negative potential zone near the grids.
基金This work is supported by the National Natural Science Foundation of China(Grant Nos.52068027,51668018,51768021).
文摘Completely weathered phyllite(CWP)soil is a kind of special soil with high swell potential,while red clay is a special soil with high shrinkage.This means that these two kinds of special soils are usually not suitable for direct use as subgrade fill.To reduce the swell index of the CWP soil and the shrinkage of red clay at the same time,it was proposed to blend the CWP soil with red clay to improve their basic characteristics.A series of swell index tests and dry-wet cycle tests of the blended soils have been carried out at varying blending ratios,compaction coefficients and moisture contents.The test results show that the free swell index of the blended soil decreases with the increase of red clay,moisture content and compaction coefficient,respectively.The fissure density of the blended soil first decreases and then increases with the blending ratio,with the lowest being zero when the blending ratio is ranging from 20%to 40%.Through particle microscopic analysis and elemental composition analysis,it is found that the neutralization effect,the dilution effect of swell minerals,and the partition effect of coarse particles play an important role in restraining expansion and shrinkage deformation of the blended soil.Based on the liquid limit requirement of Chinese Railway Design Code(TB 10001-2016),the optimal blending ratio of red clay has been proposed to be 50%.Compared with the CWP soil,the free load swell index of the blended soil is reduced by 45.0%and the fissure density is reduced by 99.3%compared with that of red clay.Therefore,it is feasible to improve the CWP soil by blending it with red clay at an optimal ratio of 50%by using the neutralization effect of the expansion of CWP and shrinkage of red clay.
基金supported by the National Science and Technology Major Projects of Drug Discovery[Grant Number 2018ZX09101-001]
文摘The Hantaan virus(HTNV)and Seoul virus(SEOV)mutants have accumulated over time.It is important to determine whether their neutralizing epitopes have evolved,thereby making the current vaccine powerless.However,it is impossible to determine by using traditional plaque reduction neutralization test(PRNT),because it requires large numbers of live mutant strains.Pseudovirus-based neutralization assays(PBNA)were developed by employing vesicular stomatitis virus(VSV)backbone incorporated with HTNV or SEOV glycoproteins(VSVDG*-HTNVG or VSVDG*-SEOVG).56 and 51 single amino acid substitutions of glycoprotein(GP)in HTNV and SEOV were selected and introduced into the reference plasmid.Then the mutant pseudoviruses were generated and tested by PBNA.The PBNA results were highly correlated with PRNT ones with R2 being 0.91 for VSVDG*-HTNVG and 0.82 for VSVDG*-SEOVG.53 HTNV mutant pseudoviruses and 46 SEOV mutants were successfully generated.Importantly,by using PBNA,we found that HTNV or SEOV immunized antisera could neutralize all the corresponding 53 HTNV mutants or the 46 SEOV mutants respectively.The novel PBNA enables us to closely monitor the effectiveness of vaccines against large numbers of evolving HTNV and SEOV.And the current vaccine remains to be effective for the naturally occurring mutants.
