0 INTRODUCTION As a high-risk construction project,underground engineering is characterized by large investment,long construction period,complexconstruction techniques,numerous unforeseeable risk factors,and significa...0 INTRODUCTION As a high-risk construction project,underground engineering is characterized by large investment,long construction period,complexconstruction techniques,numerous unforeseeable risk factors,and significantenvironmental impacts.Identifying potentialdisaster risks from the intricate web of influencing factors plays a critical role in ensuring project safety.展开更多
Layered rock masses represent complex geological formations commonly encountered in the surrounding rock of deep engineering excavations(Hou et al.,2019;Xu et al.,2017;Yang C H et al.,2009;Xian and Tan,1989).These roc...Layered rock masses represent complex geological formations commonly encountered in the surrounding rock of deep engineering excavations(Hou et al.,2019;Xu et al.,2017;Yang C H et al.,2009;Xian and Tan,1989).These rock masses are predominantly composed of sedimentary,para-metamorphic,and volcanic rock types,characterized by a set of prominent,primary bedding structural planes(layers)exhibiting relatively consistent orientations and significant spatial continuity.展开更多
The performance and price of copper-based micro linear products are determined by the diameter uniformity.How to accurately detect the wire diameter of long-length copper based micro linear products without cutting or...The performance and price of copper-based micro linear products are determined by the diameter uniformity.How to accurately detect the wire diameter of long-length copper based micro linear products without cutting or damage has always been a technical concern for production enterprises.Herein,a novel approach was developed for nondestructive detection of the average diameter at any given segment of a long copper wire by assessing the adsorption capacity of arginine on its surface.The amount of adsorbent on the surface of the copper wire exhibits a positive correlation with the area,which can be detected by extractive electrospray ionization mass spectrometry(EESI-MS)after online elution with ammonia.The experimental results demonstrated that the analysis can be completed within 15 min,with a good linear relationship between copper wires with different diameters and the adsorption capacity of arginine.The linear correlation coefficient R2was 0.995,the relative standard deviation was 1.10%-2.81%,and the detection limit reached 2.5μm(length of segment=4 cm),showing potential applications for facile measurement of the average diameter of various metal wires.展开更多
The temperature effect of rock failure has primarily focused on high temperature and large temperature gradients.However,the temperature range of engineered rocks in high ground temperature tunnel is generally within ...The temperature effect of rock failure has primarily focused on high temperature and large temperature gradients.However,the temperature range of engineered rocks in high ground temperature tunnel is generally within 100℃.For this,this study conducts real-time thermomechanical coupling tests with small temperature gradient within the engineering temperature.We analyzed rock mechanical parameter,rock failure characteristics,and acoustic emission(AE)and energy characteristics.The results indicate that the strength,peak strain,elastic modulus,and peak energy storage of sandstone decrease with increasing temperature.The peak AE count of sandstone in triaxial test at high temperature decreases with increasing temperature.The RA(Rising time/Amplitude)and AF(Average frequency)parameters associated with the AE signals indicate that the shear and tensile cracks are produced almost simultaneously throughout the rock failure process with increasing temperature.The PFC(particle flow code)simulation results show that the crack number of PBM(parallel bond model)specimen at high σ_(3) is significantly higher than that at low σ_(3) and the cracks number difference under high and low σ_(3) also rises as the temperature increases.Finally,the strength attenuation characteristics are explained by the competition and coupling action of temperature and σ_(3).This paper provides theoretical insights into rock failure mechanisms under thermomechanical coupling related to underground engineering.展开更多
Species endangerment represents one of the most pressing challenges to global ecological stability.The latest assessments reveal that many plant species face imminent extinction threats due to factors such as climate ...Species endangerment represents one of the most pressing challenges to global ecological stability.The latest assessments reveal that many plant species face imminent extinction threats due to factors such as climate change,habitat loss,invasive species,and overexploitation(Thuiller et al.,2005;Humphreys et al.,2019).Consequently,understanding the mechanisms driving plant endangerment is urgently required to inform effective conservation strategies and mitigate further losses.展开更多
AIM:To comprehensively investigate the relationship between outer retinal layer thickness and age in normal eyes.METHODS:One hundred normal eyes of 100 subjects who underwent spectral-domain optical coherence tomograp...AIM:To comprehensively investigate the relationship between outer retinal layer thickness and age in normal eyes.METHODS:One hundred normal eyes of 100 subjects who underwent spectral-domain optical coherence tomography(SD-OCT)were included in this retrospective study.The distances between the external limiting membrane(ELM)line and the photoreceptor inner segment/outer segment(IS/OS)line(ELM-IS/OS),the IS/OS line and the cone outer segment tips(COST)line(IS/OS-COST),the COST line and the retinal pigment epithelium(RPE)complex(COST-RPE)and the full retinal thickness(RT)were measured at the fovea and on four quarters.The relationship between thickness and age or sex was then analysed.RESULTS:A thinner RT was observed in women in a multiple regression analysis(men:234.47±16.79μm;women:223.13±15.43μm).The RT on the nasal quarter and the ELM-IS/OS thickness at the fovea and on the four quarters were significantly and negatively correlated with age.The IS/OS-COST and COST-RPE thicknesses at the fovea and on the four quarters were not significantly correlated with age or sex,respectively.The RT at the fovea was significantly thinner than on the four quarters.The ELM-IS/OS,IS/OS-COST and COST-RPE thicknesses at the fovea were significantly thicker than on the four quarters.CONCLUSION:In normal eyes,the RT thickness on the nasal quarter and the ELM-IS/OS thickness were significantly and negatively correlated with age.The IS/OS-COST and COST-RPE thicknesses were not significantly correlated with age or sex.展开更多
Huge quantities of zinc leaching residues(ZLRs) generated from zinc production are dumped continuously around the world and pose a potential environmental threat because of their considerable amounts of entrained heav...Huge quantities of zinc leaching residues(ZLRs) generated from zinc production are dumped continuously around the world and pose a potential environmental threat because of their considerable amounts of entrained heavy metals(mainly lead). Most ZLRs have not been properly treated and the valuable metals in them have not yet been effectively recovered. Herein, the deep cleaning of a ZLR and recovery of valuable metals via a hydrometallurgical route were investigated. The cleaning process consists of two essential stages: acid leaching followed by calcium chloride leaching. The optimum conditions for extracting zinc, copper, and indium by acid leaching were a sulfuric acid concentration of 200 g·L^(-1), a liquid/solid ratio of 4:1(m L/g), a leaching time of 2 h, and a temperature of 90°C. For lead and silver extractions, the optimum conditions were a calcium chloride concentration of 400 g·L^(-1), a pH value of 1.0, a leaching time of 1 h, and a temperature of 30°C. After calcium chloride leaching, silver and lead were extracted out and the lead was finally recovered as electrolytic lead by electrowinning. The anglesite phase, which poses the greatest potential environmental hazard, was removed from the ZLR after deep cleaning, thus reducing the cost of environmental management of ZLRs. The treatment of chlorine and spent electrolyte generated in the process was discussed.展开更多
A novel industrial process was designed for the highly selective production of ethylbenzene. It comprised of a reactor vessel, vapor phase ethylene feed stream, benzene and transalkylation feed stream. Especially the ...A novel industrial process was designed for the highly selective production of ethylbenzene. It comprised of a reactor vessel, vapor phase ethylene feed stream, benzene and transalkylation feed stream. Especially the product stream containing ethylbenzene was used to heat the reactor vessel, which consisted of an alkylation section, an upper heat exchange section, and a bottom heat exchange section. In such a novel reactor, vapor phase benzene and liquid phase benzene were coexisted due to the heat produced by isothermal reaction between the upper heat exchange section and the bottom heat exchange section. The process was demonstrated by the thermodynamic analysis and experimental results. In fact, during the 1010 hour-life-test of gas phase ethene with gas phase-liquid phase benzene alkylation reaction, the ethene conversion was above 95%, and the ethylbenzene selectivity was above 83% （only benzene feed） and even higher than 99% （benzene plus transalkylation feed）. At the same time, the xylene content in the ethylbenzene was less than 100 ppm when the reaction was carried out under the reaction conditions of 140-185℃ of temperature, 1.6-2.1 MPa of pressure, 3.0-5.5 of benzene/ethylene mole ratio, 4-6 v% of transalkylation feed/（benzene＋transalkylation feed）, 0.19-0.27 h^-1 of ethene space velocity, and 1000 g of 3998 catalyst loaded. Thus, compared with the conventional ethylbenzene synthesis route, the transalkylation reactor could be omitted in this novel industrial process.展开更多
YAP（yes-associated protein） is a transcriptional factor that is negatively regulated by Hippo pathway, a conserved pathway for the development and size control of multiple organs. The exact function of YAP in bone h...YAP（yes-associated protein） is a transcriptional factor that is negatively regulated by Hippo pathway, a conserved pathway for the development and size control of multiple organs. The exact function of YAP in bone homeostasis remains controversial. Here we provide evidence for YAP＇s function in promoting osteogenesis, suppressing adipogenesis, and thus maintaining bone homeostasis.YAP is selectively expressed in osteoblast（OB）-lineage cells. Conditionally knocking out Yap in the OB lineage in mice reduces cell proliferation and OB differentiation and increases adipocyte formation, resulting in a trabecular bone loss. Mechanistically, YAP interacts with β-catenin and is necessary for maintenance of nuclear β-catenin level and Wnt/β-catenin signaling. Expression of β-catenin in YAP-deficient BMSCs（bone marrow stromal cells） diminishes the osteogenesis deficit. These results thus identify YAP-β-catenin as an important pathway for osteogenesis during adult bone remodeling and uncover a mechanism underlying YAP regulation of bone homeostasis.展开更多
The pyrolysis of phytoremediated giant reed(Arundo donax)biomass could cause secondary pollution of heavy metals.The stabilization of heavy metals in the pyrolysis process with external materials such as Al2O3,CaCO3,F...The pyrolysis of phytoremediated giant reed(Arundo donax)biomass could cause secondary pollution of heavy metals.The stabilization of heavy metals in the pyrolysis process with external materials such as Al2O3,CaCO3,FeCl3and NaOH,wasstudied.The results showed that37%As and97%Cd in biochar were stabilized when giant reed powder was pyrolyzed at250°Cwith5%Al2O3for2h.Furthermore,59%Pb in biochar was stabilized at400°C with5%CaCO3for1h.Under biochar produced inoptimized pyrolysis conditions,Cd mainly existed in a residual fraction,while Pb and As mainly existed in oxidizable fraction inBCR analysis.In XRD analysis,As was only found in Ca2As2O7;Cd in biochar mainly existed in Cd(AlCl4)2,CdPbO3or CdSO3;and Pb mainly existed as Pb3O2SO4.展开更多
The transformation behavior of ferrous sulfate was examined during hematite precipitation for iron removal in hydrometallurgical zinc.Specifically,the effects of the method used for oxygen supply(pre-crystallization o...The transformation behavior of ferrous sulfate was examined during hematite precipitation for iron removal in hydrometallurgical zinc.Specifically,the effects of the method used for oxygen supply(pre-crystallization or pre-oxidation of ferrous sulfate)and temperature(170–190℃)on the redissolution and oxidation–hydrolysis of ferrous sulfate were studied.The precipitation characteristics and phase characterization of the hematite product were investigated.The results showed that the solubility of ferrous sulfate was considerably lower at elevated temperatures.The dissolution behavior of ferrous sulfate crystals was influenced by both the concentrations of free acid and zinc sulfate and the oxydrolysis of ferrous ions.Rapid oxydrolysis of ferrous ions may serve as the dissolution driving force.Hematite precipitation proceeded via the following sequential steps:crystallization,redissolution,oxidation,and precipitation of ferrous sulfate.The dissolution of ferrous sulfate was slow,which helped to maintain a low supersaturation environment,thereby affording the production of high-grade hematite.展开更多
Time-sensitive networks(TSNs)support not only traditional best-effort communications but also deterministic communications,which send each packet at a deterministic time so that the data transmissions of networked con...Time-sensitive networks(TSNs)support not only traditional best-effort communications but also deterministic communications,which send each packet at a deterministic time so that the data transmissions of networked control systems can be precisely scheduled to guarantee hard real-time constraints.No-wait scheduling is suitable for such TSNs and generates the schedules of deterministic communications with the minimal network resources so that all of the remaining resources can be used to improve the throughput of best-effort communications.However,due to inappropriate message fragmentation,the realtime performance of no-wait scheduling algorithms is reduced.Therefore,in this paper,joint algorithms of message fragmentation and no-wait scheduling are proposed.First,a specification for the joint problem based on optimization modulo theories is proposed so that off-the-shelf solvers can be used to find optimal solutions.Second,to improve the scalability of our algorithm,the worst-case delay of messages is analyzed,and then,based on the analysis,a heuristic algorithm is proposed to construct low-delay schedules.Finally,we conduct extensive test cases to evaluate our proposed algorithms.The evaluation results indicate that,compared to existing algorithms,the proposed joint algorithm improves schedulability by up to 50%.展开更多
AIM:To quantitatively evaluate the effect of the combined use of 577-nm subthreshold micropulse macular laser(SML)and multi-point mode pan retinal laser photocoagulation(PRP)on severe non-proliferative diabetic retino...AIM:To quantitatively evaluate the effect of the combined use of 577-nm subthreshold micropulse macular laser(SML)and multi-point mode pan retinal laser photocoagulation(PRP)on severe non-proliferative diabetic retinopathy(NPDR)with central-involved diabetic macular edema(CIDME)using optical coherence tomography angiography(OCTA).METHODS:In this observational clinical study,86 eyes of 86 NPDR patients with CIDME who underwent SML and PRP treatment were included.Images were obtained 1 d before laser and post-laser(1 d,1 wk,1,3,and 6 mo)using AngioV ue software 2.0.Best corrected visual acuity(BCVA,LogM AR),foveal avascular zone area(FAZ),choriocapillary flow area(Ch F),parafoveal vessel density(PVD),capillary density inside disc(CDD),peripapillary capillary density(PCD),macular ganglion cell complex thickness(m GCCT),central macular thickness(CMT),and subfoveal choroidal thickness(ChT)were compared between pre-and post-laser treatment.RESULTS:BCVA remained stable during 6 mo postlaser therapy(pre-laser vs 6 mo post-laser:0.53±0.21 vs 0.5±0.15,P>0.05).PVD,ChF,ChT,CMT,and mGCCT significantly increased 1 d post-laser therapy[pre-laser vs 1 d post-laser:superficial PVD(%),40.51±3.42 vs 42.43±4.68;deep PVD(%),42.66±3.67 vs 44.78±4.52;ChF,1.72±0.21 vs 1.9±0.12 mm^2;ChT,302.45±69.74 vs 319.38±70.93μm;CMT,301.65±110.78 vs 320.86±105.62μm;m GCCT,105.71±10.72 vs 115.46±9.64μm;P<0.05].However,PVD,ChF and ChT decreased to less than baseline level at 6 mo postlaser therapy(pre-laser vs 6 mo post-laser:superficial PVD(%),40.51±3.42 vs 36.32±4.19;deep PVD(%),42.66±3.67 vs 38.76±3.74;Ch F,1.72±0.21 vs 1.62±0.09 mm^2;Ch T,302.45±69.74 vs 289.61±67.55μm;P<0.05),whereas CMT and mG CCT decreased to baseline level at 6 mo postlaser therapy(CMT,301.65±110.78 vs 297.77±90.23μm;m GCCT,105.71±10.72 vs 107.05±11.81μm;P>0.05).Moreover,FAZ continuously increased while CDD and PCD continuously decreased in 6 mo after laser therapy.CMT and ChT had a significant positive correlation with ChF and PVD in most post-laser stages.CONCLUSION:During a 6-month follow-up period after combined use of SML and PRP therapy,BCVA remained stable and there was a decreased trend in macular edema.Blood flow increased at 1 d post-laser therapy and reduced at 6 mo post-laser therapy.展开更多
The effect of the addition of 1-butyl-3-methylimidazolium tetrafluoroborate （[C4mim][BF4]） on the formation rates of CO2 hydrates was investigate. The isothermal and isobaric methods were used to measure the formati...The effect of the addition of 1-butyl-3-methylimidazolium tetrafluoroborate （[C4mim][BF4]） on the formation rates of CO2 hydrates was investigate. The isothermal and isobaric methods were used to measure the formation rates of CO2 hydrates. As compared to those of pure water, the data of phase equilibrium changed greatly. The effects of pressure, temperature, and the concentration of [C4mim][BF4] aqueous solution on the formation rates of CO2 hydrates were investigated. With a constant concentration of [C4mim][BF4], the rate of gas consumption was enhanced with the lowering of experimental temperature. However, a decrease in pressure exerted an opposite effect on the rate of gas consumption. Moreover, the addition of [C4mim][BF4] raised the equilibrium pressure of hydrate formation at the same temperature.展开更多
Twin curved tunnels are often encountered in shield tunnelling,where significant complexities in densely exploited underground space are observed.In this study,the ground settlement and tunnel deformation due to twin-...Twin curved tunnels are often encountered in shield tunnelling,where significant complexities in densely exploited underground space are observed.In this study,the ground settlement and tunnel deformation due to twin-curved shield tunnelling in soft ground were investigated using numerical simulation and field monitoring.Different curvature radii of twin curved tunnels and subsequent effects of tunnel construction were considered to reveal the tunnelling effect on ground surface settlement and tunnel deformation.The results show that the settlement trough yields one offset towards inside of curved shield tunnelling.The location of settlement trough and maximum settlement were affected by curvature radius but except for the shape and width of settlement trough.Adjacent parallel twin-curved shield tunnelling could increase the offset of existing settlement trough and maximum settlement.Then,an empirical prediction of surface settlement trough due to twin-curved shield tunnelling with same tunnel diameters in soft clay was proposed,which was applicable to curvature radius less than 800 m.Finally,a minimum radius of 600 m of curvature tunnel was proposed in terms of allowable convergence deformation of tunnel.The result could provide guidance on safety evaluation for twin curved shield tunnelling construction.展开更多
基金supported by the National Natural Science Foundation of China(Nos.42107211 and 42130719)the Natural Science Foundation of Sichuan Province(No.2025ZNSFSC0097)the open project of State Key Laboratory of Performance Monitoring and Protecting of Rail Transit Infrastructure,East China Jiaotong University(No.HJGZ2022104).
文摘0 INTRODUCTION As a high-risk construction project,underground engineering is characterized by large investment,long construction period,complexconstruction techniques,numerous unforeseeable risk factors,and significantenvironmental impacts.Identifying potentialdisaster risks from the intricate web of influencing factors plays a critical role in ensuring project safety.
基金supported by the National Natural Science Foundation of China(Nos.42107211 and U23A20651)the Natural Science Foundation of Sichuan Province(No.2025ZNSFSC0097)。
文摘Layered rock masses represent complex geological formations commonly encountered in the surrounding rock of deep engineering excavations(Hou et al.,2019;Xu et al.,2017;Yang C H et al.,2009;Xian and Tan,1989).These rock masses are predominantly composed of sedimentary,para-metamorphic,and volcanic rock types,characterized by a set of prominent,primary bedding structural planes(layers)exhibiting relatively consistent orientations and significant spatial continuity.
基金supported by the National Natural Science Foundation of China(No.22422402)National Key Research and Development Program of China(No.2022YFF0705300)Key Research and Development Program of Jiangxi Province(No.20232BBG70004)。
文摘The performance and price of copper-based micro linear products are determined by the diameter uniformity.How to accurately detect the wire diameter of long-length copper based micro linear products without cutting or damage has always been a technical concern for production enterprises.Herein,a novel approach was developed for nondestructive detection of the average diameter at any given segment of a long copper wire by assessing the adsorption capacity of arginine on its surface.The amount of adsorbent on the surface of the copper wire exhibits a positive correlation with the area,which can be detected by extractive electrospray ionization mass spectrometry(EESI-MS)after online elution with ammonia.The experimental results demonstrated that the analysis can be completed within 15 min,with a good linear relationship between copper wires with different diameters and the adsorption capacity of arginine.The linear correlation coefficient R2was 0.995,the relative standard deviation was 1.10%-2.81%,and the detection limit reached 2.5μm(length of segment=4 cm),showing potential applications for facile measurement of the average diameter of various metal wires.
基金supported by the National Natural Science Foundation of China(Grant Nos.42107211 and 42130719)the Natural Science Foundation of Sichuan Province(Grant No.2025ZNSFSC0097).
文摘The temperature effect of rock failure has primarily focused on high temperature and large temperature gradients.However,the temperature range of engineered rocks in high ground temperature tunnel is generally within 100℃.For this,this study conducts real-time thermomechanical coupling tests with small temperature gradient within the engineering temperature.We analyzed rock mechanical parameter,rock failure characteristics,and acoustic emission(AE)and energy characteristics.The results indicate that the strength,peak strain,elastic modulus,and peak energy storage of sandstone decrease with increasing temperature.The peak AE count of sandstone in triaxial test at high temperature decreases with increasing temperature.The RA(Rising time/Amplitude)and AF(Average frequency)parameters associated with the AE signals indicate that the shear and tensile cracks are produced almost simultaneously throughout the rock failure process with increasing temperature.The PFC(particle flow code)simulation results show that the crack number of PBM(parallel bond model)specimen at high σ_(3) is significantly higher than that at low σ_(3) and the cracks number difference under high and low σ_(3) also rises as the temperature increases.Finally,the strength attenuation characteristics are explained by the competition and coupling action of temperature and σ_(3).This paper provides theoretical insights into rock failure mechanisms under thermomechanical coupling related to underground engineering.
基金supported by the National Key R&D Program of China(2022YFC3400300).
文摘Species endangerment represents one of the most pressing challenges to global ecological stability.The latest assessments reveal that many plant species face imminent extinction threats due to factors such as climate change,habitat loss,invasive species,and overexploitation(Thuiller et al.,2005;Humphreys et al.,2019).Consequently,understanding the mechanisms driving plant endangerment is urgently required to inform effective conservation strategies and mitigate further losses.
文摘AIM:To comprehensively investigate the relationship between outer retinal layer thickness and age in normal eyes.METHODS:One hundred normal eyes of 100 subjects who underwent spectral-domain optical coherence tomography(SD-OCT)were included in this retrospective study.The distances between the external limiting membrane(ELM)line and the photoreceptor inner segment/outer segment(IS/OS)line(ELM-IS/OS),the IS/OS line and the cone outer segment tips(COST)line(IS/OS-COST),the COST line and the retinal pigment epithelium(RPE)complex(COST-RPE)and the full retinal thickness(RT)were measured at the fovea and on four quarters.The relationship between thickness and age or sex was then analysed.RESULTS:A thinner RT was observed in women in a multiple regression analysis(men:234.47±16.79μm;women:223.13±15.43μm).The RT on the nasal quarter and the ELM-IS/OS thickness at the fovea and on the four quarters were significantly and negatively correlated with age.The IS/OS-COST and COST-RPE thicknesses at the fovea and on the four quarters were not significantly correlated with age or sex,respectively.The RT at the fovea was significantly thinner than on the four quarters.The ELM-IS/OS,IS/OS-COST and COST-RPE thicknesses at the fovea were significantly thicker than on the four quarters.CONCLUSION:In normal eyes,the RT thickness on the nasal quarter and the ELM-IS/OS thickness were significantly and negatively correlated with age.The IS/OS-COST and COST-RPE thicknesses were not significantly correlated with age or sex.
基金financially supported by the National Natural Science Foundation of China (Nos. U1302274 and 51674026)the Fundamental Research Funds for the Central Universities (No. 230201606500078)the Yunnan Technical Innovation and Personnel Training Program
文摘Huge quantities of zinc leaching residues(ZLRs) generated from zinc production are dumped continuously around the world and pose a potential environmental threat because of their considerable amounts of entrained heavy metals(mainly lead). Most ZLRs have not been properly treated and the valuable metals in them have not yet been effectively recovered. Herein, the deep cleaning of a ZLR and recovery of valuable metals via a hydrometallurgical route were investigated. The cleaning process consists of two essential stages: acid leaching followed by calcium chloride leaching. The optimum conditions for extracting zinc, copper, and indium by acid leaching were a sulfuric acid concentration of 200 g·L^(-1), a liquid/solid ratio of 4:1(m L/g), a leaching time of 2 h, and a temperature of 90°C. For lead and silver extractions, the optimum conditions were a calcium chloride concentration of 400 g·L^(-1), a pH value of 1.0, a leaching time of 1 h, and a temperature of 30°C. After calcium chloride leaching, silver and lead were extracted out and the lead was finally recovered as electrolytic lead by electrowinning. The anglesite phase, which poses the greatest potential environmental hazard, was removed from the ZLR after deep cleaning, thus reducing the cost of environmental management of ZLRs. The treatment of chlorine and spent electrolyte generated in the process was discussed.
基金This work is supported by the National 973 Project of China (2009CB623501)
文摘A novel industrial process was designed for the highly selective production of ethylbenzene. It comprised of a reactor vessel, vapor phase ethylene feed stream, benzene and transalkylation feed stream. Especially the product stream containing ethylbenzene was used to heat the reactor vessel, which consisted of an alkylation section, an upper heat exchange section, and a bottom heat exchange section. In such a novel reactor, vapor phase benzene and liquid phase benzene were coexisted due to the heat produced by isothermal reaction between the upper heat exchange section and the bottom heat exchange section. The process was demonstrated by the thermodynamic analysis and experimental results. In fact, during the 1010 hour-life-test of gas phase ethene with gas phase-liquid phase benzene alkylation reaction, the ethene conversion was above 95%, and the ethylbenzene selectivity was above 83% （only benzene feed） and even higher than 99% （benzene plus transalkylation feed）. At the same time, the xylene content in the ethylbenzene was less than 100 ppm when the reaction was carried out under the reaction conditions of 140-185℃ of temperature, 1.6-2.1 MPa of pressure, 3.0-5.5 of benzene/ethylene mole ratio, 4-6 v% of transalkylation feed/（benzene＋transalkylation feed）, 0.19-0.27 h^-1 of ethene space velocity, and 1000 g of 3998 catalyst loaded. Thus, compared with the conventional ethylbenzene synthesis route, the transalkylation reactor could be omitted in this novel industrial process.
基金supported in part by grants from the National Institutes of Health(AG051773)and VA(BX000838)
文摘YAP（yes-associated protein） is a transcriptional factor that is negatively regulated by Hippo pathway, a conserved pathway for the development and size control of multiple organs. The exact function of YAP in bone homeostasis remains controversial. Here we provide evidence for YAP＇s function in promoting osteogenesis, suppressing adipogenesis, and thus maintaining bone homeostasis.YAP is selectively expressed in osteoblast（OB）-lineage cells. Conditionally knocking out Yap in the OB lineage in mice reduces cell proliferation and OB differentiation and increases adipocyte formation, resulting in a trabecular bone loss. Mechanistically, YAP interacts with β-catenin and is necessary for maintenance of nuclear β-catenin level and Wnt/β-catenin signaling. Expression of β-catenin in YAP-deficient BMSCs（bone marrow stromal cells） diminishes the osteogenesis deficit. These results thus identify YAP-β-catenin as an important pathway for osteogenesis during adult bone remodeling and uncover a mechanism underlying YAP regulation of bone homeostasis.
基金Projects(21577176,41271330) supported by the National Natural Science Foundation of China
文摘The pyrolysis of phytoremediated giant reed(Arundo donax)biomass could cause secondary pollution of heavy metals.The stabilization of heavy metals in the pyrolysis process with external materials such as Al2O3,CaCO3,FeCl3and NaOH,wasstudied.The results showed that37%As and97%Cd in biochar were stabilized when giant reed powder was pyrolyzed at250°Cwith5%Al2O3for2h.Furthermore,59%Pb in biochar was stabilized at400°C with5%CaCO3for1h.Under biochar produced inoptimized pyrolysis conditions,Cd mainly existed in a residual fraction,while Pb and As mainly existed in oxidizable fraction inBCR analysis.In XRD analysis,As was only found in Ca2As2O7;Cd in biochar mainly existed in Cd(AlCl4)2,CdPbO3or CdSO3;and Pb mainly existed as Pb3O2SO4.
基金supported by National Natural Science Foundation of China(61100159,61233007)National High Technology Research and Development Program of China(863 Program)(2011AA040103)+2 种基金Foundation of Chinese Academy of Sciences(KGCX2-EW-104)Financial Support of the Strategic Priority Research Program of Chinese Academy of Sciences(XDA06021100)the Cross-disciplinary Collaborative Teams Program for Science,Technology and Innovation,of Chinese Academy of Sciences-Network and System Technologies for Security Monitoring and Information Interaction in Smart Grid Energy Management System for Micro-smart Grid
基金Projects(51804146,51964029,51664030,51564030)supported by the National Natural Science Foundation of ChinaProject(2018YFC1900402)supported by the National Key Research and Development Program of ChinaProject supported by the Analysis and Testing Center of Kunming University of Science and Technology,China
文摘The transformation behavior of ferrous sulfate was examined during hematite precipitation for iron removal in hydrometallurgical zinc.Specifically,the effects of the method used for oxygen supply(pre-crystallization or pre-oxidation of ferrous sulfate)and temperature(170–190℃)on the redissolution and oxidation–hydrolysis of ferrous sulfate were studied.The precipitation characteristics and phase characterization of the hematite product were investigated.The results showed that the solubility of ferrous sulfate was considerably lower at elevated temperatures.The dissolution behavior of ferrous sulfate crystals was influenced by both the concentrations of free acid and zinc sulfate and the oxydrolysis of ferrous ions.Rapid oxydrolysis of ferrous ions may serve as the dissolution driving force.Hematite precipitation proceeded via the following sequential steps:crystallization,redissolution,oxidation,and precipitation of ferrous sulfate.The dissolution of ferrous sulfate was slow,which helped to maintain a low supersaturation environment,thereby affording the production of high-grade hematite.
基金partially supported by National Key Research and Development Program of China(2018YFB1700200)National Natural Science Foundation of China(61972389,61903356,61803368,U1908212)+2 种基金Youth Innovation Promotion Association of the Chinese Academy of Sciences,National Science and Technology Major Project(2017ZX02101007-004)Liaoning Provincial Natural Science Foundation of China(2020-MS-034,2019-YQ-09)China Postdoctoral Science Foundation(2019M661156)。
文摘Time-sensitive networks(TSNs)support not only traditional best-effort communications but also deterministic communications,which send each packet at a deterministic time so that the data transmissions of networked control systems can be precisely scheduled to guarantee hard real-time constraints.No-wait scheduling is suitable for such TSNs and generates the schedules of deterministic communications with the minimal network resources so that all of the remaining resources can be used to improve the throughput of best-effort communications.However,due to inappropriate message fragmentation,the realtime performance of no-wait scheduling algorithms is reduced.Therefore,in this paper,joint algorithms of message fragmentation and no-wait scheduling are proposed.First,a specification for the joint problem based on optimization modulo theories is proposed so that off-the-shelf solvers can be used to find optimal solutions.Second,to improve the scalability of our algorithm,the worst-case delay of messages is analyzed,and then,based on the analysis,a heuristic algorithm is proposed to construct low-delay schedules.Finally,we conduct extensive test cases to evaluate our proposed algorithms.The evaluation results indicate that,compared to existing algorithms,the proposed joint algorithm improves schedulability by up to 50%.
基金Supported by the Natural Science Foundation of Guangdong Province(No.2015A030313019)the Sun Yat-sen Clinical Research Cultivation Project(No.SYS-C-201705)。
文摘AIM:To quantitatively evaluate the effect of the combined use of 577-nm subthreshold micropulse macular laser(SML)and multi-point mode pan retinal laser photocoagulation(PRP)on severe non-proliferative diabetic retinopathy(NPDR)with central-involved diabetic macular edema(CIDME)using optical coherence tomography angiography(OCTA).METHODS:In this observational clinical study,86 eyes of 86 NPDR patients with CIDME who underwent SML and PRP treatment were included.Images were obtained 1 d before laser and post-laser(1 d,1 wk,1,3,and 6 mo)using AngioV ue software 2.0.Best corrected visual acuity(BCVA,LogM AR),foveal avascular zone area(FAZ),choriocapillary flow area(Ch F),parafoveal vessel density(PVD),capillary density inside disc(CDD),peripapillary capillary density(PCD),macular ganglion cell complex thickness(m GCCT),central macular thickness(CMT),and subfoveal choroidal thickness(ChT)were compared between pre-and post-laser treatment.RESULTS:BCVA remained stable during 6 mo postlaser therapy(pre-laser vs 6 mo post-laser:0.53±0.21 vs 0.5±0.15,P>0.05).PVD,ChF,ChT,CMT,and mGCCT significantly increased 1 d post-laser therapy[pre-laser vs 1 d post-laser:superficial PVD(%),40.51±3.42 vs 42.43±4.68;deep PVD(%),42.66±3.67 vs 44.78±4.52;ChF,1.72±0.21 vs 1.9±0.12 mm^2;ChT,302.45±69.74 vs 319.38±70.93μm;CMT,301.65±110.78 vs 320.86±105.62μm;m GCCT,105.71±10.72 vs 115.46±9.64μm;P<0.05].However,PVD,ChF and ChT decreased to less than baseline level at 6 mo postlaser therapy(pre-laser vs 6 mo post-laser:superficial PVD(%),40.51±3.42 vs 36.32±4.19;deep PVD(%),42.66±3.67 vs 38.76±3.74;Ch F,1.72±0.21 vs 1.62±0.09 mm^2;Ch T,302.45±69.74 vs 289.61±67.55μm;P<0.05),whereas CMT and mG CCT decreased to baseline level at 6 mo postlaser therapy(CMT,301.65±110.78 vs 297.77±90.23μm;m GCCT,105.71±10.72 vs 107.05±11.81μm;P>0.05).Moreover,FAZ continuously increased while CDD and PCD continuously decreased in 6 mo after laser therapy.CMT and ChT had a significant positive correlation with ChF and PVD in most post-laser stages.CONCLUSION:During a 6-month follow-up period after combined use of SML and PRP therapy,BCVA remained stable and there was a decreased trend in macular edema.Blood flow increased at 1 d post-laser therapy and reduced at 6 mo post-laser therapy.
基金the Youth Innovation Foundation of Petroleum Science (04E7031)New Century Excellent Person Program (NCET-06-0088)the National Natural Science Foundation of China (40673043 and 20576073)
文摘The effect of the addition of 1-butyl-3-methylimidazolium tetrafluoroborate （[C4mim][BF4]） on the formation rates of CO2 hydrates was investigate. The isothermal and isobaric methods were used to measure the formation rates of CO2 hydrates. As compared to those of pure water, the data of phase equilibrium changed greatly. The effects of pressure, temperature, and the concentration of [C4mim][BF4] aqueous solution on the formation rates of CO2 hydrates were investigated. With a constant concentration of [C4mim][BF4], the rate of gas consumption was enhanced with the lowering of experimental temperature. However, a decrease in pressure exerted an opposite effect on the rate of gas consumption. Moreover, the addition of [C4mim][BF4] raised the equilibrium pressure of hydrate formation at the same temperature.
基金financially supported by the National Natural Science Foundation of China(Grant No.42307260)the Sichuan Natural Science Foundation(Grant No.2023NSFSC0882)the Open Project of the Research Center of Tunnelling and Underground Engineering of Ministry of Education(Grant No.TUC2022-03).
文摘Twin curved tunnels are often encountered in shield tunnelling,where significant complexities in densely exploited underground space are observed.In this study,the ground settlement and tunnel deformation due to twin-curved shield tunnelling in soft ground were investigated using numerical simulation and field monitoring.Different curvature radii of twin curved tunnels and subsequent effects of tunnel construction were considered to reveal the tunnelling effect on ground surface settlement and tunnel deformation.The results show that the settlement trough yields one offset towards inside of curved shield tunnelling.The location of settlement trough and maximum settlement were affected by curvature radius but except for the shape and width of settlement trough.Adjacent parallel twin-curved shield tunnelling could increase the offset of existing settlement trough and maximum settlement.Then,an empirical prediction of surface settlement trough due to twin-curved shield tunnelling with same tunnel diameters in soft clay was proposed,which was applicable to curvature radius less than 800 m.Finally,a minimum radius of 600 m of curvature tunnel was proposed in terms of allowable convergence deformation of tunnel.The result could provide guidance on safety evaluation for twin curved shield tunnelling construction.
