Introduction Virtual reality(VR)and transcutaneous electrical nerve stimulation(TENS)have emerged as effective interventions for pain reduction.However,their standalone applications often yield limited analgesic effec...Introduction Virtual reality(VR)and transcutaneous electrical nerve stimulation(TENS)have emerged as effective interventions for pain reduction.However,their standalone applications often yield limited analgesic effects,particularly in certain painful conditions.Aims Our hypothesis was that the combination of VR with TENS in a synchronous manner could produce the best analgesic effect among the four experimental conditions.Methods To address this challenge,we proposed a novel pain modulation strategy that synchronously combines VR and TENS,aiming to capitalise on both techniques'complementary pain modulation mechanisms.Thirty-two healthy subjects participated in the study and underwent three types of interventions:VR alone,a combination of VR with conventional TENS,and a combination of VR with synchronous TENS.Additionally,a control condition with no intervention was included.Perceived pain intensity,pain unpleasantness,positive and negativeaffect scores,and electroencephalographic(EEG)data were collected before and after the interventions.To delve into the potential moderating role of pain intensity on the analgesic efficacy of VR combined with synchronous TENS,we incorporated two distinct levels of painful stimuli:one representing mild to moderate pain(ie,low pain)and the other representing moderate to severe pain(ie,high pain).Results Our findings revealed that both combination interventions exhibited superior analgesic effects compared with the VR-alone intervention when exposed to low and high pain stimuli.Notably,the combination of VR with synchronous TENS demonstrated greater analgesic efficacy than the combination of VR with conventional TENS.EEG data further supported these results,indicating that both combination interventions elicited a greater reduction in event-related potential magnitude compared with the VR-alone intervention during exposure to low and high pain stimuli.Moreover,the synchronous combination intervention induced a more significant reduction in N2 amplitude than the VR-alone intervention during exposure to low pain stimuli.No significant differences in EEG response changes were detected between the two combination interventions.Both combination interventions resulted in a greater reduction in negative affect compared with the VR-alone intervention.Conclusions Altogether,our study highlights the effectiveness of the synchronous combination of VR and TENS in enhancing pain modulation.These findings offer valuable insights for developing innovative pain treatments,emphasising the importance of tailored and multifaceted therapeutic approaches for various painful conditions.展开更多
The exploration of low-cost and efficient bifunctional electrocatalysts for oxygen evolution reaction and hydrogen evolution reaction through tuning the chemical composition is strongly required for sustainable resour...The exploration of low-cost and efficient bifunctional electrocatalysts for oxygen evolution reaction and hydrogen evolution reaction through tuning the chemical composition is strongly required for sustainable resources. Herein, we developed a bimetallic cobalt–manganese sulfide supported on Ni foam(CMS/Ni) via a solvothermal method. It has discovered that after combining with the pure Co_9S_8 and Mn S, the morphologies of CMS/Ni have modulated. The obtained three-dimensionally hexagram-like CMS/Ni nanosheets have a significant increase in electrochemical active surface area and charge transport ability. More than that, the synergetic effect of Co and Mn has also presented in this composite. Benefiting from these, the CMS/Ni electrode shows great performance toward hydrogen evolution reaction and oxygen evolution reaction in basic medium, comparing favorably to that ofthe pure Co_9S_8/Ni and Mn S/Ni. More importantly, this versatile CMS/Ni can catalyze the water splitting in a twoelectrode system at a potential of 1.47 V, and this electrolyzer can be efficiently driven by a 1.50 V commercial dry battery.展开更多
Recovering the iron(Fe)and phosphorus(P)contained in steelmaking slags not only reduces the environmental burden caused by the accumulated slag,but also is the way to develop a circular economy and achieve sustainable...Recovering the iron(Fe)and phosphorus(P)contained in steelmaking slags not only reduces the environmental burden caused by the accumulated slag,but also is the way to develop a circular economy and achieve sustainable development in the steel industry.We had pre-viously found the possibility of recovering Fe and P resources,i.e.,magnetite(Fe_(3)O_(4)) and calcium phosphate(Ca_(10)P_(6)O_(25)),contained in steel-making slags by adjusting oxygen partial pressure and adding modifier B_(2)O_(3).As a fundamental study for efficiently recovering Fe and P from steelmaking slag,in this study,the crystallization behavior of the CaO-SiO_(2)-FeO-P_(2)O_(5)-B_(2)O_(3) melt has been observed in situ,using a confocal scanning laser microscope(CLSM).The kinetics of nucleation and growth of Fe-and P-rich phases have been calculated using a classical crys-tallization kinetic theory.During cooling,a Fe_(3)O_(4) phase with faceted morphology was observed as the 1st precipitated phase in the isothermal interval of 1300-1150℃,while Ca_(10)P_(6)O_(25),with rod-shaped morphology,was found to be the 2nd phase to precipitate in the interval of 1150-1000℃.The crystallization abilities of Fe_(3)O_(4) and Ca_(10)P_(6)O_(25) phases in the CaO-SiO_(2)-FeO-P_(2)O_(5)-B_(2)O_(3) melt were quantified with the in-dex of(T_(U)−T_(I))/T_(I)(where T_(I) represents the peak temperature of the nucleation rate and TU stands for that of growth rate),and the crystalliza-tion ability of Fe_(3)O_(4) was found to be larger than that of Ca_(10)P_(6)O_(25) phase.The range of crystallization temperature for Fe_(3)O_(4) and Ca_(10)P_(6)O_(25) phases was optimized subsequently.The Fe_(3)O_(4) and Ca_(10)P_(6)O_(25) phases are the potential sources for ferrous feedstock and phosphate fertilizer,respectively.展开更多
To remove the key impurity elements,P and B,from primary Si simultaneously,Sr and Zr co-addition to Al-Si alloy systems during solvent refining has been investigated.Sr reacts with Al,Si,and P in the melt to form a P-...To remove the key impurity elements,P and B,from primary Si simultaneously,Sr and Zr co-addition to Al-Si alloy systems during solvent refining has been investigated.Sr reacts with Al,Si,and P in the melt to form a P-containing Al_(2)Si_(2)Sr phase and Zr reacts with B to form a ZrB_(2) phase.In the Al-Si-Sr-Zr system,high removal fractions of P and B in the primary Si,with 84.8%-98.4%and 90.7%-96.7%,respectively,are achieved at the same time,respectively.The best removal effect is obtained in the sample with the addition of Sr-32000+Zr-3000μg·kg^(-1),and the removal fractions of P and B in the purified Si reach 98.4%and 96.1%.Compared with the Sr/Zr single-addition,the removal effects of Sr and Zr co-addition on P and B do not show a significant downward trend,indicating that the nucleation and growth of the B/P-containing impurity phases are mutually independent.Finally,an evolution model is proposed to describe the nucleation and the growth stages of Sr/Zr-containing compound phases,which reveals the interaction between the impurity phases and the primary Si.展开更多
天然气资源丰富、价格低廉,因而被广泛用作燃料.天然气的主要成分是甲烷,未燃烧完的甲烷所产生的温室效应是二氧化碳的21倍,所带来的环境问题引起越来越多的研究者关注.但甲烷是最稳定的非极性有机小分子,C–H键能高达434 k J/mol,大多...天然气资源丰富、价格低廉,因而被广泛用作燃料.天然气的主要成分是甲烷,未燃烧完的甲烷所产生的温室效应是二氧化碳的21倍,所带来的环境问题引起越来越多的研究者关注.但甲烷是最稳定的非极性有机小分子,C–H键能高达434 k J/mol,大多数催化剂很难将其在很低的温度在完全转化.C?H键的活化解离是催化甲烷燃烧最关键的一步,而活化C–H键方式主要有两大类:(1)均裂活化机制,一般用在贵金属催化剂上;(2)异裂活化机制,往往发生在过渡金属氧化物上.比较而言,贵金属催化剂,尤其是Pd,往往具有更优异的低温催化活性,但价格昂贵,从而限制了其广泛使用.因此,开发更加高效的非贵金属催化剂用于废气中未转化的甲烷完全氧化是亟待解决的问题.含有Co和Ni的尖晶石氧化物具有良好的催化甲烷燃烧活性,有望代替贵金属催化剂,但要求在低于400°C完全转化,仍具有一定挑战.另一方面,Ni^(3+)和Co^(3+)哪个是活性中心,还具有一定争议.因此,我们通过水热法和共沉淀法合成一系列表面暴露不同数目的Ni^(3+)和Co^(3+)来探究表面高氧化态Co和Ni跟活性之间的关系.XRD和TEM结果表明,相比于水热法合成的水热法合成的发生明显的晶格收缩现象,这是由于在尖晶石体相中大量小半径Ni^(3+)(0.053 nm)取代了大半径Co^(3+)(0.055 nm)所致.同时还发现,水热合成的尖晶石具有多孔纳米片层结构,相比于共沉淀法合成的尖晶石具有更大的比表面积,催化活性也更高.XPS分析发现,催化甲烷燃烧的活性随着表面含量增加而提高.结合文献分析和本文的实验结果推测,表面的Ni^(3+)和Co^(3+)都可作为解离C?H键的活性中心.水热60小时合成的纳米片表面的数量最多,所以具有最优异的催化性能,大约在280°C甲烷转化50%.当加入10%(体积比)的水,在高空速工况下对催化活性影响不大,主要是因为长时间水热合成的尖晶石表面缺陷少,对水的吸附弱,这可通过O 1s图谱得到印证.总之,这些研究结果能够给甲烷活化和开发更加高效和低成本催化剂一些启示.展开更多
A flexible asymmetric supercapacitor(ASC)based on a Co Al-layered double hydroxide(Co Al-LDH)electrode and a reduced graphene oxide(r GO) electrode was successfully fabricated. The Co Al-LDH electrode as a positive el...A flexible asymmetric supercapacitor(ASC)based on a Co Al-layered double hydroxide(Co Al-LDH)electrode and a reduced graphene oxide(r GO) electrode was successfully fabricated. The Co Al-LDH electrode as a positive electrode was synthesized by directly growing Co Al-LDH nanosheet arrays on a carbon cloth(CC)through a facile hydrothermal method, and it delivered a specific capacitance of 616.9 F g^(-1)at a current density of1 A g^(-1). The r GO electrode as a negative electrode was synthesized by coating r GO on the CC via a simple dipcoating method and revealed a specific capacitance of110.0 F g^(-1)at a current density of 2 A g^(-1). Ultimately,the advanced ASC offered a broad voltage window(1.7 V)and exhibited a high superficial capacitance of1.77 F cm^(-2)at 2 m A cm^(-2)and a high energy density of0.71 m Wh cm^(-2)at a power density of 17.05 m W cm^(-2),along with an excellent cycle stability(92.9% capacitance retention over 8000 charge–discharge cycles).展开更多
为简化电解水催化剂的合成过程和优化电解水操作系统,双功能电解水催化剂的研究,特别是在碱性条件下同时具有优异催化氢析出和氧析出反应性能的双功能电催化剂的研究尤为重要.其中,过渡金属硫化物,特别是CoNi硫化物,被报道有与氢化酶类...为简化电解水催化剂的合成过程和优化电解水操作系统,双功能电解水催化剂的研究,特别是在碱性条件下同时具有优异催化氢析出和氧析出反应性能的双功能电催化剂的研究尤为重要.其中,过渡金属硫化物,特别是CoNi硫化物,被报道有与氢化酶类似的催化活性中心,从而具有优异的催化氢析出和催化氧析出反应性能.虽然有关对过渡金属硫化物的研究很多,但主要集中在具有一维纳米线和二维纳米片形貌结构的过渡金属硫化物.不幸的是,这些形貌结构的过渡金属硫化物在电催化过程中容易聚集和受限于电荷传输能力.三维纳米结构的材料具有较大的比表面积以分布更多的活性位点和拥有良好的电子传输能力,所以,开发三维纳米结构的过渡金属硫化物材料可能是改进其催化电解水性能的一个好途径.本文采用简单的两步水热法,通过硫化合成的CoNi前体得到了长于泡沫镍上的三维百合花状的CoNi_2S_4(CoNi_2S_4/Ni).它只需要54 mV的过电位即可获得10 mA cm^(-2)的催化氢析出反应电流,是最好的碱性催化氢析出反应电极材料之一.它在驱动100 mA cm^(-2)的催化氧析出反应电流时也只需要328 mV的过电位.另外,把CoNi_2S_4/Ni分别作为阴极和阳极组装成双电极碱性水电解槽时,它只需要1.56 V的电压即可获取10 mA cm^(-2)的催化全电解水电流并具有良好的催化全电解水稳定性.扫描电子显微镜、透射电子显微镜和N_2吸脱附曲线测试结果表明,该三维百合花状的CoNi_2S_4/Ni的表面粗糙度高和拥有多孔特性.多孔结构的CoNi_2S_4/Ni可提供更多可接触的催化活性位点,也有利于催化过程中的电解质和生成的气体的扩散与传递.交流阻抗图谱测试结果表明,CoNi_2S_4/Ni具有良好的电子传输能力.另外,不同于前期对尖晶石结构的硫化物AB_2S_4的研究结果,XPS结果表明,CoNi_2S_4/Ni中含有Ni^(б+)和S^(б–)活性物种,表明CoNi_2S_4具有与活性氢化酶类似的活性中心.Ni^(δ+)和S^(δ–)可分别作为氢氧根和质子的接收体,协助促进吸附的水分子的分离,从而提高材料的催化性能.所以,Ni^(δ+)和S^(δ–)活性物种的出现,大比表面积的三维百合花状多孔结构和良好的电荷传输能力等特性集合于CoNi_2S_4/Ni上使得CoNi_2S_4/Ni具有优异的催化氢析出和催化氧析出反应性能.展开更多
As the unique power entrance,the pantograph-catenary electrical contact system maintains the efficiency and reliability of power transmission for the high-speed train.Along with the fast development of high-speed rail...As the unique power entrance,the pantograph-catenary electrical contact system maintains the efficiency and reliability of power transmission for the high-speed train.Along with the fast development of high-speed railways all over the world,some commercialized lines are built for covering the remote places under harsh environment,especially in China;these environmental elements including wind,sand,rain,thunder,ice and snow need to be considered during the design of the pantograph-catenary system.The pantograph-catenary system includes the pantograph,the contact wire and the interface—pantograph slide.As the key component,this pantograph slide plays a critical role in reliable power transmission under dynamic condition.The fundamental material characteristics of the pantograph slide and contact wire such as electrical conductivity,impact resistance,wear resistance,etc.,directly determine the sliding electrical contact performance of the pantograph-catenary system;meanwhile,different detection methods of the pantograph-catenary system are crucial for the reliability of service and maintenance.In addition,the challenges brought from extreme operational conditions are discussed,taking the Sichuan-Tibet Railway currently under construction as a special example with the high-altitude climate.The outlook for developing the ultra-high-speed train equipped with the novel pantograph-catenary system which can address the harsher operational environment is also involved.This paper has provided a comprehensive review of the high-speed railway pantograph-catenary systems,including its progress,challenges,outlooks in the history and future.展开更多
This paper concerns an optimal dividend-penalty problem for the risk models with surplus-dependent premiums.The objective is to maximize the difference of the expected cumulative discounted dividend payments received ...This paper concerns an optimal dividend-penalty problem for the risk models with surplus-dependent premiums.The objective is to maximize the difference of the expected cumulative discounted dividend payments received until the moment of ruin and a discounted penalty payment taken at the moment of ruin.Since the value function may be not smooth enough to be the classical solution of the HJB equation,the viscosity solution is involved.The optimal value function can be characterized as the smallest viscosity supersolution of the HJB equation and the optimal dividend-penalty strategy has a band structure.Finally,some numerical examples with gamma distribution for the claims are analyzed.展开更多
Although Zn metal is an ideal anode candidate for aqueous batteries owing to its high theoretical capacity,lower cost,and safety,its service life and efficiency are damaged by severe hydrogen evolution reaction,self-c...Although Zn metal is an ideal anode candidate for aqueous batteries owing to its high theoretical capacity,lower cost,and safety,its service life and efficiency are damaged by severe hydrogen evolution reaction,self-corrosion,and dendrite growth.Herein,a thickness-controlled ZnS passivation layer was fabricated on the Zn metal surface to obtain Zn@ZnS electrode through oxidation–orientation sulfuration by the liquid-and vapor-phase hydrothermal processes.Benefiting from the chemical inertness of the ZnS interphase,the as-prepared Zn@ZnS electrode presents an excellent anti-corrosion and undesirable hydrogen evolution reaction.Meanwhile,the thickness-optimized ZnS layer with an unbalanced charge distribution represses dendrite growth by guiding Zn plating/stripping,leading to long service life.Consequently,the Zn@Zn S presented 300 cycles in the symmetric cells with a 42 mV overpotential,200 cycles in half cells with a 78 mV overpotential,and superb rate performance in Zn||NH;V;O;full cells.展开更多
Two-dimensional(2D)hexagonal boron nitride(hBN),due to its extraordinary thermal,chemical,and optical properties,has arisen as an enticing material for the research community to explore for various applications,includ...Two-dimensional(2D)hexagonal boron nitride(hBN),due to its extraordinary thermal,chemical,and optical properties,has arisen as an enticing material for the research community to explore for various applications,including the use of site defects in hBN as single photon emitters(SPEs).In this review,we systematically summarize recent advanced strategies towards the controllable synthesis of 2D hBN using chemical vapor deposition,towards a full control of the domain size,orientation,morphology,layer number,and stacking order,etc.Moreover,we review the underlying mechanisms for single photon emission(SPE)in hBN and methods to selectively generate and tune the SPEs.Defects(e.g.,carbon substituted defects)are discussed for the potential use as emission sites.We finally give an outlook of future challenges and opportunities on desirable hBN synthesis and further investigation of SPEs in hBN,targeting to utilize hBN as single photon emitters in an industrial scale.展开更多
The construction of efficient and durable electrocatalysts with highly dispersed metal clusters and hydrophilic surface for alkaline hydrogen evolution reaction(HER)remains a great challenge.Herein,we prepared hydroph...The construction of efficient and durable electrocatalysts with highly dispersed metal clusters and hydrophilic surface for alkaline hydrogen evolution reaction(HER)remains a great challenge.Herein,we prepared hydrophilic nanocomposites of Ru clusters(~1.30 nm)anchored on Na^(+),K^(+)-decorated porous carbon(Ru/Na^(+),K^(+)-PC)through hydrothermal method and subsequent annealing treatment at 500℃.The Ru/Na^(+),K^(+)-PC exhibits ultralow overpotential of 7 mV at 10 mA·cm^(-2),mass activity of 15.7 A·mgRu^(-1)at 100 mV,and long-term durability of 20,000 cycles potential cycling and 200 h chronopotentiometric measurement with a negligible decrease in activity,much superior to benchmarked commercial Pt/C.Density functional theory based calculations show that the energy barrier of H-OH bond breaking is efficiently reduced due to the presence of Na and K ions,thus favoring the Volmer step.Furthermore,the Ru/Na^(+),K^(+)-PC effectively employs solar energy for obtaining H_(2)in both alkaline water and seawater electrolyzer.This finding provides a new strategy to construct high-performance and cost-effective alkaline HER electrocatalyst.展开更多
There is a great demand for high performance rapid repair mortar(RRM)because of the wide use of cement concrete.Solid-waste-based sulfoaluminate cement(WSAC)is very suitable as a green cementitious material for repair...There is a great demand for high performance rapid repair mortar(RRM)because of the wide use of cement concrete.Solid-waste-based sulfoaluminate cement(WSAC)is very suitable as a green cementitious material for repair materials because of its characteristics of high early-age strength and short setting time.However,the influence and optimization of various factors of WSAC-based RRM,such as water-to-RRM ratio,binder-to-sand ratio and additives,as well as the further solid waste replacement of aggregate,remain to be studied.This paper comprehensively studied the influence of the above factors on the performance of WSAC-based RRM and obtained a green high-performance RRM by optimizing these factors.The experimental results showed that the early and late strength of the obtained RRM is excellent,and the setting time and fluidity are appropriate,which reflected good mechanical properties and construction performance.Ordinary Portland cement(OPC)doping could not improve RRM strength.It was feasible to prepare RRM with gold tailing sand replacing part of the quartz sand.This paper provides data and a theoretical basis for the preparation of high-performance RRM based on solid waste,expanding the high value utilization of solid waste,which is conducive to the development of a low carbon society.展开更多
Lyme disease(LD)is a tick-transmitted infection caused by Borrelia burgdorferi sensu lato species,which include B.burgdorferi,Borrelia afzelii and Borrelia garinii.The majority of patients with early LD can be cured b...Lyme disease(LD)is a tick-transmitted infection caused by Borrelia burgdorferi sensu lato species,which include B.burgdorferi,Borrelia afzelii and Borrelia garinii.The majority of patients with early LD can be cured by the standard treatment,yet some still suffer from posttreatment LD syndrome.The presence of Borrelia persisters has been proposed as a contributing factor,because they cannot be completely eradicated by the currently used antibiotics for LD.Finding new pharmaceuticals targeting Borrelia persisters is crucial for developing more effective treatments.Here,we first confirmed the existence of persisters in B.garinii and B.afzelii cultures and then conducted a high-throughput screening of a customdrug library against persister-rich stationary-phase B.garinii and B.afzelii cultures.Among 2427 compounds screened,hypocrellin A(HA),anthracycline class of drugs and topical antibiotics along with some other natural compounds were identified to have strong potential for killing persisters of B.garinii and B.afzelii.HA was the most active anti-Borrelia compound,capable of eradicating stationary-phase Borrelia persisters,in particular when combined with doxycycline and/or ceftriaxone.Liposoluble antioxidant vitamin E was found to antagonize the activity of HA,indicating HA’s target is the cell membrane where HA triggers the generation of reactive oxygen species in the presence of light.HA was found to have distinct bactericidal activity against Borrelia species but had poor or no activity against gram-positive and gram-negative bacteria.Identification of the abovementioned drug candidates may help develop more effective therapies for LD.展开更多
There have been hundreds of millions of cases of coronavirus disease 2019(COVID-19),which is caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).With the growing population of recovered patients,it i...There have been hundreds of millions of cases of coronavirus disease 2019(COVID-19),which is caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).With the growing population of recovered patients,it is crucial to understand the long-term consequences of the disease and management strategies.Although COVID-19 was initially considered an acute respiratory illness,recent evidence suggests that manifestations including but not limited to those of the cardiovascular,respiratory,neuropsychiatric,gastrointestinal,reproductive,and musculoskeletal systems may persist long after the acute phase.These persistent manifestations,also referred to as long COVID,could impact all patients with COVID-19 across the full spectrum of illness severity.Herein,we comprehensively review the current literature on long COVID,highlighting its epidemiological understanding,the impact of vaccinations,organ-specific sequelae,pathophysiological mechanisms,and multidisciplinary management strategies.In addition,the impact of psychological and psychosomatic factors is also underscored.Despite these crucial findings on long COVID,the current diagnostic and therapeutic strategies based on previous experience and pilot studies remain inadequate,and well-designed clinical trials should be prioritized to validate existing hypotheses.Thus,we propose the primary challenges concerning biological knowledge gaps and efficient remedies as well as discuss the corresponding recommendations.展开更多
Lung cancer has the highest mortality rate among all cancers in the world.Hence,early diagnosis and personal-ized treatment plans are crucial to improving its 5-year survival rate.Chest computed tomography(CT)serves a...Lung cancer has the highest mortality rate among all cancers in the world.Hence,early diagnosis and personal-ized treatment plans are crucial to improving its 5-year survival rate.Chest computed tomography(CT)serves as an essential tool for lung cancer screening,and pathology images are the gold standard for lung cancer diagnosis.However,medical image evaluation relies on manual labor and suffers from missed diagnosis or misdiagnosis,and physician heterogeneity.The rapid development of artificial intelligence(AI)has brought a whole novel op-portunity for medical task processing,demonstrating the potential for clinical application in lung cancer diagnosis and treatment.AI technologies,including machine learning and deep learning,have been deployed extensively for lung nodule detection,benign and malignant classification,and subtype identification based on CT images.Furthermore,AI plays a role in the non-invasive prediction of genetic mutations and molecular status to provide the optimal treatment regimen,and applies to the assessment of therapeutic efficacy and prognosis of lung cancer patients,enabling precision medicine to become a reality.Meanwhile,histology-based AI models assist patholo-gists in typing,molecular characterization,and prognosis prediction to enhance the efficiency of diagnosis and treatment.However,the leap to extensive clinical application still faces various challenges,such as data sharing,standardized label acquisition,clinical application regulation,and multimodal integration.Nevertheless,AI holds promising potential in the field of lung cancer to improve cancer care.展开更多
The production of titanium dioxide(a necessary industrial color additive)can generate massive amount of titanium gypsum,a hard-to-treat solid waste.Diverse metallic impurities,heavy metals and reddish color in titaniu...The production of titanium dioxide(a necessary industrial color additive)can generate massive amount of titanium gypsum,a hard-to-treat solid waste.Diverse metallic impurities,heavy metals and reddish color in titanium gypsum make it difficult to be used in building materials like other by-product gypsums.As a result,most of titanium gypsum in China is just stored and has caused serious environmental issues.In this study,titanium gypsum,which contained high contents of impurities and heavy metals,was synergistically used with other three solid wastes to prepare sulfoaluminate cementitious material(SACM)for the first time.The mass proportion of titanium gypsum in the raw materials exceeded 25%.The chemical,mechanical and heavy metal leaching characteristics of this solid waste-based SACM were tested via XRD,XRF,ICP-OES,etc.The main components and metallic impurities of titanium gypsum could be transformed to the components of the main mineral of SACM,ye’elimite.The compressive strength of the prepared SACM reached 38.2,59.7 and 95.8 MPa at 1-day,3-day,and 28-day hydration,respectively,indicating the features of rapidly hardening and high strength.Importantly,the solid waste-based SACM could effectively solidify the heavy metals contained in titanium gypsum and other raw material during thje hydration process.The retention ratio of total Cr reached 97.5%,and other heavy metals were almost not detected in the leachate of SACM.This study provided a feasible approach to utilize titanium gypsum to produce high-performance,green building material,and might promote the massive utilization of this solid waste.展开更多
基金supported by the National Natural Science Foundation of China(32071061)and Beijing Natural Science Foundation(JQ22018).
文摘Introduction Virtual reality(VR)and transcutaneous electrical nerve stimulation(TENS)have emerged as effective interventions for pain reduction.However,their standalone applications often yield limited analgesic effects,particularly in certain painful conditions.Aims Our hypothesis was that the combination of VR with TENS in a synchronous manner could produce the best analgesic effect among the four experimental conditions.Methods To address this challenge,we proposed a novel pain modulation strategy that synchronously combines VR and TENS,aiming to capitalise on both techniques'complementary pain modulation mechanisms.Thirty-two healthy subjects participated in the study and underwent three types of interventions:VR alone,a combination of VR with conventional TENS,and a combination of VR with synchronous TENS.Additionally,a control condition with no intervention was included.Perceived pain intensity,pain unpleasantness,positive and negativeaffect scores,and electroencephalographic(EEG)data were collected before and after the interventions.To delve into the potential moderating role of pain intensity on the analgesic efficacy of VR combined with synchronous TENS,we incorporated two distinct levels of painful stimuli:one representing mild to moderate pain(ie,low pain)and the other representing moderate to severe pain(ie,high pain).Results Our findings revealed that both combination interventions exhibited superior analgesic effects compared with the VR-alone intervention when exposed to low and high pain stimuli.Notably,the combination of VR with synchronous TENS demonstrated greater analgesic efficacy than the combination of VR with conventional TENS.EEG data further supported these results,indicating that both combination interventions elicited a greater reduction in event-related potential magnitude compared with the VR-alone intervention during exposure to low and high pain stimuli.Moreover,the synchronous combination intervention induced a more significant reduction in N2 amplitude than the VR-alone intervention during exposure to low pain stimuli.No significant differences in EEG response changes were detected between the two combination interventions.Both combination interventions resulted in a greater reduction in negative affect compared with the VR-alone intervention.Conclusions Altogether,our study highlights the effectiveness of the synchronous combination of VR and TENS in enhancing pain modulation.These findings offer valuable insights for developing innovative pain treatments,emphasising the importance of tailored and multifaceted therapeutic approaches for various painful conditions.
基金supported by National Natural Science Foundation of China(21576113 and 21376105)Foshan Innovative and Entrepreneurial Research Team Program(No.2014IT100062)
文摘The exploration of low-cost and efficient bifunctional electrocatalysts for oxygen evolution reaction and hydrogen evolution reaction through tuning the chemical composition is strongly required for sustainable resources. Herein, we developed a bimetallic cobalt–manganese sulfide supported on Ni foam(CMS/Ni) via a solvothermal method. It has discovered that after combining with the pure Co_9S_8 and Mn S, the morphologies of CMS/Ni have modulated. The obtained three-dimensionally hexagram-like CMS/Ni nanosheets have a significant increase in electrochemical active surface area and charge transport ability. More than that, the synergetic effect of Co and Mn has also presented in this composite. Benefiting from these, the CMS/Ni electrode shows great performance toward hydrogen evolution reaction and oxygen evolution reaction in basic medium, comparing favorably to that ofthe pure Co_9S_8/Ni and Mn S/Ni. More importantly, this versatile CMS/Ni can catalyze the water splitting in a twoelectrode system at a potential of 1.47 V, and this electrolyzer can be efficiently driven by a 1.50 V commercial dry battery.
基金supported by Jiangsu University(No.19JDG011)the Project of the National Natural Science Foundation of China(Nos.51874272,52111540265)the Open Foundation of State Key Laboratory of Mineral Processing(No.BGRIMM-KJSKL-2022-23).
文摘Recovering the iron(Fe)and phosphorus(P)contained in steelmaking slags not only reduces the environmental burden caused by the accumulated slag,but also is the way to develop a circular economy and achieve sustainable development in the steel industry.We had pre-viously found the possibility of recovering Fe and P resources,i.e.,magnetite(Fe_(3)O_(4)) and calcium phosphate(Ca_(10)P_(6)O_(25)),contained in steel-making slags by adjusting oxygen partial pressure and adding modifier B_(2)O_(3).As a fundamental study for efficiently recovering Fe and P from steelmaking slag,in this study,the crystallization behavior of the CaO-SiO_(2)-FeO-P_(2)O_(5)-B_(2)O_(3) melt has been observed in situ,using a confocal scanning laser microscope(CLSM).The kinetics of nucleation and growth of Fe-and P-rich phases have been calculated using a classical crys-tallization kinetic theory.During cooling,a Fe_(3)O_(4) phase with faceted morphology was observed as the 1st precipitated phase in the isothermal interval of 1300-1150℃,while Ca_(10)P_(6)O_(25),with rod-shaped morphology,was found to be the 2nd phase to precipitate in the interval of 1150-1000℃.The crystallization abilities of Fe_(3)O_(4) and Ca_(10)P_(6)O_(25) phases in the CaO-SiO_(2)-FeO-P_(2)O_(5)-B_(2)O_(3) melt were quantified with the in-dex of(T_(U)−T_(I))/T_(I)(where T_(I) represents the peak temperature of the nucleation rate and TU stands for that of growth rate),and the crystalliza-tion ability of Fe_(3)O_(4) was found to be larger than that of Ca_(10)P_(6)O_(25) phase.The range of crystallization temperature for Fe_(3)O_(4) and Ca_(10)P_(6)O_(25) phases was optimized subsequently.The Fe_(3)O_(4) and Ca_(10)P_(6)O_(25) phases are the potential sources for ferrous feedstock and phosphate fertilizer,respectively.
基金supported by the National Natural Science Foundation of China(Nos.51804294,51874272,52111540265)Anhui Provincial Natural Science Foundation(No.1808085ME121)+4 种基金the Key Laboratory of Photovoltaic and Energy Conservation Materials,Chinese Academy of Science(No.PECL2021QN003)Hefei Institutes of Physical Science,Chinese Academy of Sciences Director’s Fund(No.YZJJZX202018)International Clean Energy Talent Program by China Scholarship CouncilOpen Foundation of State Key Laboratory of Mineral Processing(No.BGRIMM-KJSKL-2022-23)Open Foundation of State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization(No.CNMRCUKF2205)。
文摘To remove the key impurity elements,P and B,from primary Si simultaneously,Sr and Zr co-addition to Al-Si alloy systems during solvent refining has been investigated.Sr reacts with Al,Si,and P in the melt to form a P-containing Al_(2)Si_(2)Sr phase and Zr reacts with B to form a ZrB_(2) phase.In the Al-Si-Sr-Zr system,high removal fractions of P and B in the primary Si,with 84.8%-98.4%and 90.7%-96.7%,respectively,are achieved at the same time,respectively.The best removal effect is obtained in the sample with the addition of Sr-32000+Zr-3000μg·kg^(-1),and the removal fractions of P and B in the purified Si reach 98.4%and 96.1%.Compared with the Sr/Zr single-addition,the removal effects of Sr and Zr co-addition on P and B do not show a significant downward trend,indicating that the nucleation and growth of the B/P-containing impurity phases are mutually independent.Finally,an evolution model is proposed to describe the nucleation and the growth stages of Sr/Zr-containing compound phases,which reveals the interaction between the impurity phases and the primary Si.
基金supported by National Natural Science Foundation of China(21376105 and 21576113)Foshan Innovative and Entepreneurial Research Team Program(No.2014IT100062)
文摘A flexible asymmetric supercapacitor(ASC)based on a Co Al-layered double hydroxide(Co Al-LDH)electrode and a reduced graphene oxide(r GO) electrode was successfully fabricated. The Co Al-LDH electrode as a positive electrode was synthesized by directly growing Co Al-LDH nanosheet arrays on a carbon cloth(CC)through a facile hydrothermal method, and it delivered a specific capacitance of 616.9 F g^(-1)at a current density of1 A g^(-1). The r GO electrode as a negative electrode was synthesized by coating r GO on the CC via a simple dipcoating method and revealed a specific capacitance of110.0 F g^(-1)at a current density of 2 A g^(-1). Ultimately,the advanced ASC offered a broad voltage window(1.7 V)and exhibited a high superficial capacitance of1.77 F cm^(-2)at 2 m A cm^(-2)and a high energy density of0.71 m Wh cm^(-2)at a power density of 17.05 m W cm^(-2),along with an excellent cycle stability(92.9% capacitance retention over 8000 charge–discharge cycles).
基金supported by the National Natural Science Foundation of China(21376105,21576113)~~
文摘为简化电解水催化剂的合成过程和优化电解水操作系统,双功能电解水催化剂的研究,特别是在碱性条件下同时具有优异催化氢析出和氧析出反应性能的双功能电催化剂的研究尤为重要.其中,过渡金属硫化物,特别是CoNi硫化物,被报道有与氢化酶类似的催化活性中心,从而具有优异的催化氢析出和催化氧析出反应性能.虽然有关对过渡金属硫化物的研究很多,但主要集中在具有一维纳米线和二维纳米片形貌结构的过渡金属硫化物.不幸的是,这些形貌结构的过渡金属硫化物在电催化过程中容易聚集和受限于电荷传输能力.三维纳米结构的材料具有较大的比表面积以分布更多的活性位点和拥有良好的电子传输能力,所以,开发三维纳米结构的过渡金属硫化物材料可能是改进其催化电解水性能的一个好途径.本文采用简单的两步水热法,通过硫化合成的CoNi前体得到了长于泡沫镍上的三维百合花状的CoNi_2S_4(CoNi_2S_4/Ni).它只需要54 mV的过电位即可获得10 mA cm^(-2)的催化氢析出反应电流,是最好的碱性催化氢析出反应电极材料之一.它在驱动100 mA cm^(-2)的催化氧析出反应电流时也只需要328 mV的过电位.另外,把CoNi_2S_4/Ni分别作为阴极和阳极组装成双电极碱性水电解槽时,它只需要1.56 V的电压即可获取10 mA cm^(-2)的催化全电解水电流并具有良好的催化全电解水稳定性.扫描电子显微镜、透射电子显微镜和N_2吸脱附曲线测试结果表明,该三维百合花状的CoNi_2S_4/Ni的表面粗糙度高和拥有多孔特性.多孔结构的CoNi_2S_4/Ni可提供更多可接触的催化活性位点,也有利于催化过程中的电解质和生成的气体的扩散与传递.交流阻抗图谱测试结果表明,CoNi_2S_4/Ni具有良好的电子传输能力.另外,不同于前期对尖晶石结构的硫化物AB_2S_4的研究结果,XPS结果表明,CoNi_2S_4/Ni中含有Ni^(б+)和S^(б–)活性物种,表明CoNi_2S_4具有与活性氢化酶类似的活性中心.Ni^(δ+)和S^(δ–)可分别作为氢氧根和质子的接收体,协助促进吸附的水分子的分离,从而提高材料的催化性能.所以,Ni^(δ+)和S^(δ–)活性物种的出现,大比表面积的三维百合花状多孔结构和良好的电荷传输能力等特性集合于CoNi_2S_4/Ni上使得CoNi_2S_4/Ni具有优异的催化氢析出和催化氧析出反应性能.
基金supported by the National Natural Science Foundation of China(Nos.U19A20105,51837009,51807167,51922090,U1966602 and 52077182)the Scientific and Technological Funds for Young Scientists of Sichuan(No.2019JDJQ0019)。
文摘As the unique power entrance,the pantograph-catenary electrical contact system maintains the efficiency and reliability of power transmission for the high-speed train.Along with the fast development of high-speed railways all over the world,some commercialized lines are built for covering the remote places under harsh environment,especially in China;these environmental elements including wind,sand,rain,thunder,ice and snow need to be considered during the design of the pantograph-catenary system.The pantograph-catenary system includes the pantograph,the contact wire and the interface—pantograph slide.As the key component,this pantograph slide plays a critical role in reliable power transmission under dynamic condition.The fundamental material characteristics of the pantograph slide and contact wire such as electrical conductivity,impact resistance,wear resistance,etc.,directly determine the sliding electrical contact performance of the pantograph-catenary system;meanwhile,different detection methods of the pantograph-catenary system are crucial for the reliability of service and maintenance.In addition,the challenges brought from extreme operational conditions are discussed,taking the Sichuan-Tibet Railway currently under construction as a special example with the high-altitude climate.The outlook for developing the ultra-high-speed train equipped with the novel pantograph-catenary system which can address the harsher operational environment is also involved.This paper has provided a comprehensive review of the high-speed railway pantograph-catenary systems,including its progress,challenges,outlooks in the history and future.
基金supported by National Natural Science Foundation of China(11471218)Hebei Higher School Science and Technology Research Projects(ZD20131017)Joint Doctoral Training Foundation of HEBUT(2018GN0001)。
文摘This paper concerns an optimal dividend-penalty problem for the risk models with surplus-dependent premiums.The objective is to maximize the difference of the expected cumulative discounted dividend payments received until the moment of ruin and a discounted penalty payment taken at the moment of ruin.Since the value function may be not smooth enough to be the classical solution of the HJB equation,the viscosity solution is involved.The optimal value function can be characterized as the smallest viscosity supersolution of the HJB equation and the optimal dividend-penalty strategy has a band structure.Finally,some numerical examples with gamma distribution for the claims are analyzed.
基金supported by the National Research Foundation funded by the government of the Republic of Korea (Nos. 2020R1I1A1A01072996 and 2021K 2A9A2A06044652)the National Natural Science Foundation of China (Nos. 52111540265 and 51874272)
文摘Although Zn metal is an ideal anode candidate for aqueous batteries owing to its high theoretical capacity,lower cost,and safety,its service life and efficiency are damaged by severe hydrogen evolution reaction,self-corrosion,and dendrite growth.Herein,a thickness-controlled ZnS passivation layer was fabricated on the Zn metal surface to obtain Zn@ZnS electrode through oxidation–orientation sulfuration by the liquid-and vapor-phase hydrothermal processes.Benefiting from the chemical inertness of the ZnS interphase,the as-prepared Zn@ZnS electrode presents an excellent anti-corrosion and undesirable hydrogen evolution reaction.Meanwhile,the thickness-optimized ZnS layer with an unbalanced charge distribution represses dendrite growth by guiding Zn plating/stripping,leading to long service life.Consequently,the Zn@Zn S presented 300 cycles in the symmetric cells with a 42 mV overpotential,200 cycles in half cells with a 78 mV overpotential,and superb rate performance in Zn||NH;V;O;full cells.
基金Z.L.acknowledge the support from Research Grant Council of Hong Kong SAR(16304518),NSFC-RGC Joint Research Scheme(N_HKUST607/17)the Innovation and Technology Commission(ITCCNERC14SC01)+3 种基金the Zhongshan City Burea of Science and Technology(2019AG018)the IER foundation(HT-JD-CXY-201907)research fund of Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory(NO.2020B1212030010)Guangdong Provincial Department of Science and Technology(grants 2020A0505090003).
文摘Two-dimensional(2D)hexagonal boron nitride(hBN),due to its extraordinary thermal,chemical,and optical properties,has arisen as an enticing material for the research community to explore for various applications,including the use of site defects in hBN as single photon emitters(SPEs).In this review,we systematically summarize recent advanced strategies towards the controllable synthesis of 2D hBN using chemical vapor deposition,towards a full control of the domain size,orientation,morphology,layer number,and stacking order,etc.Moreover,we review the underlying mechanisms for single photon emission(SPE)in hBN and methods to selectively generate and tune the SPEs.Defects(e.g.,carbon substituted defects)are discussed for the potential use as emission sites.We finally give an outlook of future challenges and opportunities on desirable hBN synthesis and further investigation of SPEs in hBN,targeting to utilize hBN as single photon emitters in an industrial scale.
基金This work was supported by the National Natural Science Foundation of China(No.21571038)Education Department of Guizhou Province(No.2021312)+4 种基金Foundation of Guizhou Province(No.2019-5666)State Key Laboratory of Coal Mine Disaster Dynamics and Control(Chongqing University,No.2011DA105287-ZR202101)Science Foundation for After graduated Students of Guizhou Province(No.YJSKYJJ2021023)State Key Laboratory of Physical Chemistry of Solid Surfaces(Xiamen University,No.202009)the Open Fund of the Key Lab of Organic Optoelectronics and Molecular Engineering(Tsinghua University).
文摘The construction of efficient and durable electrocatalysts with highly dispersed metal clusters and hydrophilic surface for alkaline hydrogen evolution reaction(HER)remains a great challenge.Herein,we prepared hydrophilic nanocomposites of Ru clusters(~1.30 nm)anchored on Na^(+),K^(+)-decorated porous carbon(Ru/Na^(+),K^(+)-PC)through hydrothermal method and subsequent annealing treatment at 500℃.The Ru/Na^(+),K^(+)-PC exhibits ultralow overpotential of 7 mV at 10 mA·cm^(-2),mass activity of 15.7 A·mgRu^(-1)at 100 mV,and long-term durability of 20,000 cycles potential cycling and 200 h chronopotentiometric measurement with a negligible decrease in activity,much superior to benchmarked commercial Pt/C.Density functional theory based calculations show that the energy barrier of H-OH bond breaking is efficiently reduced due to the presence of Na and K ions,thus favoring the Volmer step.Furthermore,the Ru/Na^(+),K^(+)-PC effectively employs solar energy for obtaining H_(2)in both alkaline water and seawater electrolyzer.This finding provides a new strategy to construct high-performance and cost-effective alkaline HER electrocatalyst.
基金National Key R&D Program of China(No.2020YFC1910000)the Shandong Natural Science Foundation Youth Project(No.ZR2020QE201).
文摘There is a great demand for high performance rapid repair mortar(RRM)because of the wide use of cement concrete.Solid-waste-based sulfoaluminate cement(WSAC)is very suitable as a green cementitious material for repair materials because of its characteristics of high early-age strength and short setting time.However,the influence and optimization of various factors of WSAC-based RRM,such as water-to-RRM ratio,binder-to-sand ratio and additives,as well as the further solid waste replacement of aggregate,remain to be studied.This paper comprehensively studied the influence of the above factors on the performance of WSAC-based RRM and obtained a green high-performance RRM by optimizing these factors.The experimental results showed that the early and late strength of the obtained RRM is excellent,and the setting time and fluidity are appropriate,which reflected good mechanical properties and construction performance.Ordinary Portland cement(OPC)doping could not improve RRM strength.It was feasible to prepare RRM with gold tailing sand replacing part of the quartz sand.This paper provides data and a theoretical basis for the preparation of high-performance RRM based on solid waste,expanding the high value utilization of solid waste,which is conducive to the development of a low carbon society.
基金the National Natural Science Foundation of China(no.81902099)the State Key Laboratory of Veterinary Etiological Biology,Lanzhou Veterinary Research Institute,Chinese Academy of Agricultural Sciences(no.SKLVEB2020KFKT005).
文摘Lyme disease(LD)is a tick-transmitted infection caused by Borrelia burgdorferi sensu lato species,which include B.burgdorferi,Borrelia afzelii and Borrelia garinii.The majority of patients with early LD can be cured by the standard treatment,yet some still suffer from posttreatment LD syndrome.The presence of Borrelia persisters has been proposed as a contributing factor,because they cannot be completely eradicated by the currently used antibiotics for LD.Finding new pharmaceuticals targeting Borrelia persisters is crucial for developing more effective treatments.Here,we first confirmed the existence of persisters in B.garinii and B.afzelii cultures and then conducted a high-throughput screening of a customdrug library against persister-rich stationary-phase B.garinii and B.afzelii cultures.Among 2427 compounds screened,hypocrellin A(HA),anthracycline class of drugs and topical antibiotics along with some other natural compounds were identified to have strong potential for killing persisters of B.garinii and B.afzelii.HA was the most active anti-Borrelia compound,capable of eradicating stationary-phase Borrelia persisters,in particular when combined with doxycycline and/or ceftriaxone.Liposoluble antioxidant vitamin E was found to antagonize the activity of HA,indicating HA’s target is the cell membrane where HA triggers the generation of reactive oxygen species in the presence of light.HA was found to have distinct bactericidal activity against Borrelia species but had poor or no activity against gram-positive and gram-negative bacteria.Identification of the abovementioned drug candidates may help develop more effective therapies for LD.
基金supported by the Science and Technology Project of Sichuan(2022ZDZX0018,2020YFG0473,2023NSFSC1889)Science and Technology Project of Chengdu(2023-YF09-00007-SN)Sichuan University from“0”to“1”Innovation Project.
文摘There have been hundreds of millions of cases of coronavirus disease 2019(COVID-19),which is caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).With the growing population of recovered patients,it is crucial to understand the long-term consequences of the disease and management strategies.Although COVID-19 was initially considered an acute respiratory illness,recent evidence suggests that manifestations including but not limited to those of the cardiovascular,respiratory,neuropsychiatric,gastrointestinal,reproductive,and musculoskeletal systems may persist long after the acute phase.These persistent manifestations,also referred to as long COVID,could impact all patients with COVID-19 across the full spectrum of illness severity.Herein,we comprehensively review the current literature on long COVID,highlighting its epidemiological understanding,the impact of vaccinations,organ-specific sequelae,pathophysiological mechanisms,and multidisciplinary management strategies.In addition,the impact of psychological and psychosomatic factors is also underscored.Despite these crucial findings on long COVID,the current diagnostic and therapeutic strategies based on previous experience and pilot studies remain inadequate,and well-designed clinical trials should be prioritized to validate existing hypotheses.Thus,we propose the primary challenges concerning biological knowledge gaps and efficient remedies as well as discuss the corresponding recommendations.
基金This work was supported by the National Natural Science Foun-dation of China(Nos.82100119,92159302)the Science and Tech-nology Project of Sichuan(Nos.2020YFG0473,2022ZDZX0018,2023NSFSC1889)+1 种基金the Chinese Postdoctoral Science Foundation(No.2021M692309)Postdoctoral Interdisciplinary Innovation Fund of Sichuan University,and the Science and Technology Achievements Transformation Foundation and Postdoctoral Program of West China Hospital,Sichuan University(Nos.CGZH21009 and 2020HXBH084).
文摘Lung cancer has the highest mortality rate among all cancers in the world.Hence,early diagnosis and personal-ized treatment plans are crucial to improving its 5-year survival rate.Chest computed tomography(CT)serves as an essential tool for lung cancer screening,and pathology images are the gold standard for lung cancer diagnosis.However,medical image evaluation relies on manual labor and suffers from missed diagnosis or misdiagnosis,and physician heterogeneity.The rapid development of artificial intelligence(AI)has brought a whole novel op-portunity for medical task processing,demonstrating the potential for clinical application in lung cancer diagnosis and treatment.AI technologies,including machine learning and deep learning,have been deployed extensively for lung nodule detection,benign and malignant classification,and subtype identification based on CT images.Furthermore,AI plays a role in the non-invasive prediction of genetic mutations and molecular status to provide the optimal treatment regimen,and applies to the assessment of therapeutic efficacy and prognosis of lung cancer patients,enabling precision medicine to become a reality.Meanwhile,histology-based AI models assist patholo-gists in typing,molecular characterization,and prognosis prediction to enhance the efficiency of diagnosis and treatment.However,the leap to extensive clinical application still faces various challenges,such as data sharing,standardized label acquisition,clinical application regulation,and multimodal integration.Nevertheless,AI holds promising potential in the field of lung cancer to improve cancer care.
基金funded by the National Key Research&Development Program of China(No.2017YFC0703100).
文摘The production of titanium dioxide(a necessary industrial color additive)can generate massive amount of titanium gypsum,a hard-to-treat solid waste.Diverse metallic impurities,heavy metals and reddish color in titanium gypsum make it difficult to be used in building materials like other by-product gypsums.As a result,most of titanium gypsum in China is just stored and has caused serious environmental issues.In this study,titanium gypsum,which contained high contents of impurities and heavy metals,was synergistically used with other three solid wastes to prepare sulfoaluminate cementitious material(SACM)for the first time.The mass proportion of titanium gypsum in the raw materials exceeded 25%.The chemical,mechanical and heavy metal leaching characteristics of this solid waste-based SACM were tested via XRD,XRF,ICP-OES,etc.The main components and metallic impurities of titanium gypsum could be transformed to the components of the main mineral of SACM,ye’elimite.The compressive strength of the prepared SACM reached 38.2,59.7 and 95.8 MPa at 1-day,3-day,and 28-day hydration,respectively,indicating the features of rapidly hardening and high strength.Importantly,the solid waste-based SACM could effectively solidify the heavy metals contained in titanium gypsum and other raw material during thje hydration process.The retention ratio of total Cr reached 97.5%,and other heavy metals were almost not detected in the leachate of SACM.This study provided a feasible approach to utilize titanium gypsum to produce high-performance,green building material,and might promote the massive utilization of this solid waste.
