This work investigated the effect of Cr and Si on the mechanical properties and oxidation resistance of press hardened steel.Results indicated that the microstructure of the Cr-Si micro-alloyed press hardened steel co...This work investigated the effect of Cr and Si on the mechanical properties and oxidation resistance of press hardened steel.Results indicated that the microstructure of the Cr-Si micro-alloyed press hardened steel consisted of lath martensite,M_(23)C_(6)carbides,and retained austenite.The retained austenite and carbides are responsible for the increase in elongation of the micro-alloyed steel.In addition,after oxidation at 930℃for 5 min,the thickness of the oxide scales on the Cr-Si micro-alloyed press hardened steel is less than 5μm,much thinner than 45.50μm-thick oxide scales on 22MnB5.The oxide scales of the Cr-Si micro-alloyed steel are composed of Fe_(2)O_(3),Fe_(3)O_(4),mixed spinel oxide(FeCr_(2)O_(4)and Fe_(2)SiO_(4)),and amorphous SiO_(2).Adding Cr and Si significantly reduces the thickness of the oxide scales and prevents the generation of the FeO phase.Due to the increase of spinel FeCr_(2)O_(4)and Fe_(2)SiO_(4)phase in the inner oxide scale and the amorphous SiO_(2)close to the substrate,the oxidation resistance of the Cr-Si micro-alloyed press hardened steel is improved.展开更多
Development of urban human settlement environments(HSEs)is an integral part of promoting high-quality and sustainable regional development and constructing a beautiful China.The city of Lanzhou,located at the geometri...Development of urban human settlement environments(HSEs)is an integral part of promoting high-quality and sustainable regional development and constructing a beautiful China.The city of Lanzhou,located at the geometric center of China,is the only provincial capital traversed by the Yellow River.Given the constraints posed by the valley topography and the need for economic development,the development of this HSE,which is located within an arid region,poses considerable challenges.Evidently,an understanding of the evolution of HSEs and drivers of changes in them contributes to high-quality,sustainable urban development in arid and semi-arid regions.An analytical model was developed using the parameters of relief degree of land surface,human comfort days,the land cover index,nighttime light index,and precipitation.This model was used in combination with population density and the gross domestic product to analyze the spatial distribution of Lanzhou's HSE and its drivers.The results showed that landscapes in Lanzhou underwent significant changes between 2000 and 2022,with an increase in building-up land(+0.946%),cultivated land(+0.134%),and forest land(+0.018%)and a decrease in grassland(-1.10%).There was significant outward expansion of the main urban zone of Lanzhou and of various county towns,with the increase in building-up land being most prominent.During this period,there were significant changes in the periphery of the core urban area and county towns in Lanzhou,with decreases moving from the urban center(the highest value)to the surrounding areas(Yongdeng County had the lowest value).The correlation between the HSE and population density grew stronger in Anning and Chengguan Districts but became weaker in Xigu and Qilihe Districts.Spatiotemporal variations in the HSE were primarily caused by climate change,followed by human activities,and were also influenced by the valley topography.Overall,the spatial distribution of population density and the HSE in Lanzhou demonstrated good consistency under the in-fluence of economic development and urbanization.展开更多
In last decade,the utilization of CO?resources in steelmaking has achieved certain metallurgical effects and the technology is maturing.In this review,we summarized the basic reaction theory of CO2,the CO2 conversion,...In last decade,the utilization of CO?resources in steelmaking has achieved certain metallurgical effects and the technology is maturing.In this review,we summarized the basic reaction theory of CO2,the CO2 conversion,and the change of energy-consumption when CO2 was introduced in converter steelmaking process.In the CO2-O2 mixed injection(COMI)process,the CO2 conversion ratio can be obtained as high as 80%or more with a control of the CO2 ratio in mixture gas and the flow rate of CO2,and the energy is saving and even the energy consumption can be reduced by 145.65 MJ/t under certain operations.In addition,a complete route of CO2 disposal technology is proposed combining the comparatively mature technologies of CO2 capture,CO2 compression,and liquid CO2 storage to improve the technology of CO2 utilization.The results are expected to form a large-scale,highly efficient,and valuable method to dispose of CO2.展开更多
AIM: To evaluate the role of probiotics in the standard triple Helicobacter pylori therapy. METHODS: In this meta-analysis, we investigated the efficacy of probiotics in a standard triple H. pylori therapy in adults. ...AIM: To evaluate the role of probiotics in the standard triple Helicobacter pylori therapy. METHODS: In this meta-analysis, we investigated the efficacy of probiotics in a standard triple H. pylori therapy in adults. Searches were mainly conducted in MEDLINE/PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials. Fourteen studies met our criteria, and the quality of these studies was assessed using the Jadad scale. We used STATA version 12.0 to extract data and to calculate the odds ratios (ORs), which are presented with the corresponding 95% confidence intervals (CIs). The data are presented as forest plots. RESULTS: The pooled ORs for the eradication rates calculated by intention-to-treat analysis and per-protocol analysis in the probiotic group vs the control group were 1.67 (95%CI: 1.38-2.02) and 1.68 (95%CI: 1.35-2.08), respectively, using the fixed-effects model. The sensitivity of the Asian studies was greater than that of the Caucasian studies (Asian: OR = 1.78, 95%CI: 1.40-2.26; Caucasian: OR = 1.48, 95%CI: 1.06-2.05). The pooled OR for the incidence of total adverse effects was signi.cantly lower in the probiotic group (OR = 0.49, 95%CI: 0.26-0.94), using the random effects model, with significant heterogeneity (I-2 = 85.7%). The incidence of diarrhea was significantly reduced in the probiotic group (OR = 0.21, 95%CI: 0.06-0.74), whereas the incidence of taste disorders, metallic taste, vomiting, nausea, and epigastric pain did not differ significantly between the probiotic group and the control group. CONCLUSION: Supplementary probiotic preparations during standard triple H. pylori therapy may improve the eradication rate, particularly in Asian patients, and the incidence of total adverse effects. (C) 2014 Baishideng Publishing Group Inc. All rights reserved.展开更多
The process model for BOF process can be applied to predict the liquid steel composition and bath temperature during the whole steelmaking process. On the basis of the traditional three-stage decarburization theory, t...The process model for BOF process can be applied to predict the liquid steel composition and bath temperature during the whole steelmaking process. On the basis of the traditional three-stage decarburization theory, the concept of mixing degree was put forward, which was used to indicate the effect of oxygen jet on decarburization. Furthermore, a more practical process model for BOF steelmaking was developed by analyzing the effect of silicon, manganese, oxygen injection rate, oxygen lance height, and bath temperature on decarburization. Process verification and end-point verification for the process model have been carried out, and the verification results show that the predic- tion accuracy of carbon content reaches 82.6% （the range of carbon content at the end-point is less than 0. 1wt%） and 85.7% （the range of carbon content at end-point is 0. 1wt% -0.7wt%） when the absolute error is less than 0.02wt% and 0.05wt%, respectively.展开更多
A three-dimensional computational fluid dynamics （CFD） model was developed to simulate a 150-t top-blown converter. The ef-fect of different lance heights on the cavity shape was investigated using the volume of flu...A three-dimensional computational fluid dynamics （CFD） model was developed to simulate a 150-t top-blown converter. The ef-fect of different lance heights on the cavity shape was investigated using the volume of fluid （VOF） method. Numerical simulation results can reflect the actual molten bath surface waves impinged by the supersonic oxygen jets. With increasing lance height, the cavity depth de-creases, and the cavity area, varying like a parabola, increases and then decreases. The cavity area maximizes at the lance height of 1.3 m. Under the three different lance heights simulated in this study, all of the largest impact velocities at the molten bath surface are between 50 m/s and 100 m/s.展开更多
A new environment-friendly free-cutting steel alloyed with elemental Sn （Y20Sn） was developed to meet the requirements of machinability and mechanical properties according to GB/T8731--1988. The machinability of the...A new environment-friendly free-cutting steel alloyed with elemental Sn （Y20Sn） was developed to meet the requirements of machinability and mechanical properties according to GB/T8731--1988. The machinability of the steel is enhanced by the segregation of elemental Sn at grain boundaries. The effect of Sn segregation on intergranular brittle fracture at normal cutting temperature from 250℃ to 400℃ is confirmed. The formation mechanism of main inclusions MnS is influenced by the presence of Sn and the attachment of Sn around MnS itself as a surfactant, and this mechanism also explains the improvement in machinability and mechanical properties of the steel. In the steel, the relevant inclusions are mainly spherical or axiolitic, and are uniformly distributed in small volume. Such inclusions improve the machinability of the steel and do not impair the mechanical properties as well. Experimental results demonstrate that the appropriate content of Sn in the steel is 0.03wt% to 0.08wt%, and the remaining composition is close to that of standard Y20 steel.展开更多
Herein, a multi-index analysis of the nickel content of an alloy, output rate of the alloy, nickel recovery rate, and iron recovery rate during the melting of laterite metallized pellets was performed. The thermodynam...Herein, a multi-index analysis of the nickel content of an alloy, output rate of the alloy, nickel recovery rate, and iron recovery rate during the melting of laterite metallized pellets was performed. The thermodynamic reduction behavior of oxides such as NiO, FeO, Fe_3 O_4, and Cr_2 O_3 was studied using the FactSage software, which revealed that SiO_2 is not conducive to the reduction of iron oxides, whereas the addition of basic oxides such as CaO and MgO is beneficial for the reduction of iron oxides. On the basis of a comprehensive analysis to achieve greater nickel recovery and lower iron recovery rates, the optimum experimental parameters in the orthogonal experiment were A3 B1 C3(t = 30 min, C/O = 0.4, R = 1.2); the indicators wNi, φalloy, ηNi, and ηFe had values of 15.0 wt%, 12.1%, 44.9%, and 96.4%, respectively. In single-factor experiments, increasing basicity(R) substantially improved the separation effect in the low-basicity range 0.5 ≤ R ≤ 0.8 but not in the high-basicity range 0.8 ≤ R ≤ 1.2. Similar results were obtained for the effect of the C/O ratio. Moreover, the recovery rate of nickel increased with increasing recovery rate of iron.展开更多
Observations of the Langmuir Probe Instrument （ISL, Instrument Sonde de Langmuir） onboard the DEMETER satellite during four years from 2006 to 2009 were used to analyze the tempo-spatial variations of electron densi...Observations of the Langmuir Probe Instrument （ISL, Instrument Sonde de Langmuir） onboard the DEMETER satellite during four years from 2006 to 2009 were used to analyze the tempo-spatial variations of electron density （Ne） and temperature （Te） in the ionosphere. Twenty four research bins with each covering an area with 10° in longitude and 2° in latitude were selected to study the spatial distributions of Ne and Te. The results indicate that both Ne and Te have strong an- nual variations in the topside ionosphere at 660 krn altitude. The semiannual anomaly and equinoctial asymmetry which are usually well known as the features of F-layer also exist in the topside ionosphere at low- and mid-latitudes. The yearly varia- tion of No is opposite to the peak electron density of the F2-1ayer （NmF2） at higher latitudes in daytime and both are similar in nighttime. Also the yearly variations of Tc at low-latitude are contrary to that at 600 km in daytime and similar in nighttime An interesting feature of nighttime Te at low-latitude is an obvious annual variation in the northern hemisphere and semian- nual variation in the southern hemisphere. The yearly variations of Te in daytime have negative and positive correlation with Ne at mid- and high-latitudes, respectively. Both Nc and Te in the neighborhood bins at the same latitude have a high correlation. In ionospheric events analyzing, this information may help to understand the characteristics of the variation and to dis- tinguish the reliable abnormality from the normal background map.展开更多
BACKGROUND Primary Sjögren's syndrome(pSS)concomitant with autoimmune hemolytic anemia(AIHA)but without eye and mouth dryness is exceedingly rare.Iguratimod(IGU)has been widely used in the treatment of pSS.Ho...BACKGROUND Primary Sjögren's syndrome(pSS)concomitant with autoimmune hemolytic anemia(AIHA)but without eye and mouth dryness is exceedingly rare.Iguratimod(IGU)has been widely used in the treatment of pSS.However,there are few reports about the application of IGU in pSS concomitant with AIHA.CASE SUMMARY Here,we present the case of a patient with pSS concomitant with AIHA but without eye and mouth dryness.The patient was initially diagnosed with hyperplastic anemia and AIHA while pSS was missed,and was finally diagnosed with pSS concomitant with AIHA.The patient was treated with IGU along with prednisone and hydroxychloroquine,and her hemoglobin,reticulocytes and IgG returned to normal levels.CONCLUSION IGU was effective for and well tolerated by our patient with pSS concomitant with AIHA,and may be a promising therapy for the treatment of this disease.展开更多
Takayasu arteritis (TA) is a chronic, nonspecific inflammatory disease of large and medium-sized vessels that primarily involves the aorta and its branches. TA involving the pulmonary arteries has a prevalence ranging...Takayasu arteritis (TA) is a chronic, nonspecific inflammatory disease of large and medium-sized vessels that primarily involves the aorta and its branches. TA involving the pulmonary arteries has a prevalence ranging from 14% to 86%, which can lead to pulmonary hypertension, a progressive increase in pulmonary artery pressure, and eventually death from right heart failure. The presentation of pulmonary arteritis (PA) is very nonspecific, with a reported misdiagnosis rate of up to 60% and a diagnosis time ranging from 1 month to more than 10 years. The clinical manifestation of pleural effusion is very rare in both TA and PA cases. Based on our literature review, this is the 6th reported case of TA with pleural effusion, and the specific mechanism of TA with pleural effusion is still unclear. The characteristics of this case and the previously reported cases are summarized in this article to improve the understanding of TA and PA and reduce the misdiagnosis rate.展开更多
Based on a current coherent jet,this study proposes a supersonic combustion(SC)coherent jet in which the main oxygen jet is surrounded by a supersonic fuel gas.The characteristics of the proposed coherent jet are anal...Based on a current coherent jet,this study proposes a supersonic combustion(SC)coherent jet in which the main oxygen jet is surrounded by a supersonic fuel gas.The characteristics of the proposed coherent jet are analyzed using experimental methods and numerical simulations in the high-temperature environment of electric arc furnace(EAF)steelmaking.The SC coherent jet achieved stable combustion in the EAF steelmaking environment.The simulated combustion temperature of the supersonic shrouding methane gas was 2930 K,slightly below the theoretical combustion temperature of methane–oxygen gas.The high speed and temperature of the supersonic flame effectively weakened the interaction between the main oxygen jet and the external ambient gas,inhibiting the radial expansion of the main oxygen jet and maintaining its high speed and low turbulence over a long distance.These features improved the impact capacity of the coherent jet and strengthened the stirring intensity in the EAF bath.展开更多
Objective:To make Galangin-PLGA nanoparticles(GL-PLGA NPs)were prepared using the biodegradable material polylactic-coglycolic acid(PLGA)as the carrier material,and the formulation was optimized.Methods:Nanoparticles ...Objective:To make Galangin-PLGA nanoparticles(GL-PLGA NPs)were prepared using the biodegradable material polylactic-coglycolic acid(PLGA)as the carrier material,and the formulation was optimized.Methods:Nanoparticles were prepared by modified emulsification-solvent evaporation method and the content of galangin was determined by HPLC.With particle size and entrapment efficiency as the indexes,single factor and orthogonal test were used to optimize the formulation,and the quality of the optimized GL-PLGA NPs was evaluated from the surface configuration,particle size distribution,Zeta potential and entrapment efficiency.Results:The optimal prescription conditions of GL-PLGA NPs were:the volume ratio of organic phase to aqueous phase was 1:8,the concentration of PVA was 1.5%,the concentration of PLGA was 1.0%,and the drug concentration was 0.2%.Under these conditions,the average particle size of GL-PLGA NPs was 249±1.32nm,polydispersity index(PDI)was 0.059,Zeta potential was-4.86mV,and the entrapment efficiency was 75.3%.The results of electron microscopy showed that the nanoparticles were spherical,uniform particle size and good dispersion.Conclusion:The preparation method is simple and stable,and GL-PLGA NPs with suitable particle size and high entrapment efficiency can be obtained.展开更多
Energy-saving in China's iron and steel industry still relies on the development and improvement of short-term energy saving technologies.Therefore,a special converter smelting technology incorporating energy savi...Energy-saving in China's iron and steel industry still relies on the development and improvement of short-term energy saving technologies.Therefore,a special converter smelting technology incorporating energy saving was proposed.To evaluate the energy-saving potential of the CO_(2)–O_(2)mixed injection(COMI)technology,collected production data were used to develop an improved techno-economic model.Calculations reveal that the technology can save energy through auxiliary material consumption,sensible heat of solid by-product,iron loss reduction,and energy recovery.The application of COMI technology in an enterprise is cost effective,involving the energy saving potential of 0.206 GJ/t,the cost of conserved energy of−48.83 yuan/GJ,and a simple payback period of 0.35 year for a 60-million-yuan investment.Sensitivity analysis shows that the investment cost and discount rate primarily influence the cost of conserved energy of the technology.As the discount rate increased,the cost of conserved energy also gradually increased.Overall,the COMI technology is an energy-saving technology with good development prospects.展开更多
Comprehensive and quantitative assessment of human physical activity in daily life is valuable for healthcare,especially for those who suffer from obesity and neurological disorders or are at high risk of dementia.Com...Comprehensive and quantitative assessment of human physical activity in daily life is valuable for healthcare,especially for those who suffer from obesity and neurological disorders or are at high risk of dementia.Common wearable devices,e.g.,smartwatches,are insufficient and inaccurate for monitoring highly dynamic limb movements and assessing human motion.Here,we report a new wearable leg movement monitoring system incorporating a custom-made motion sensor with machine learning algorithm to perceive human motion accurately and comprehensively during diverse walking and running actions.The system enables real-time multimodal perceptions of personal identity,motion state,locomotion speed,and energy expenditure for wearers.A general law of extracting real-time metabolic energy from leg movements is verified although individual gaits show differences.In addition,we propose a novel sensing configuration combining unilateral lower leg movement velocity with its angular rate to achieve high accuracy and good generalizability while simplifying the wearable system.Advanced performances in personal identification(accuracy of 98.7%)and motion-state recognition(accuracy of 93.7%)are demonstrated.The wearable system also exhibites high-precision real-time estimations of locomotion speed(error of 3.04%to 9.68%)and metabolic energy(error of 4.18%to 14.71%)for new subjects across various time-varying conditions.The wearable system allows reliable leg movement monitoring and quantitative assessment of bodily kinematic and kinetic behaviors during daily activities,as well as safe identity authentication by gait parameters,which would greatly facilitate smart life,personal healthcare,and rehabilitation training.展开更多
A novel approach to reduce Ni content for the 310S austenitic stainless steel was proposed.The nano-ceramic additive(L)was applied to 310S steel to replace part of Ni element and reduce the cost.By means of thermal si...A novel approach to reduce Ni content for the 310S austenitic stainless steel was proposed.The nano-ceramic additive(L)was applied to 310S steel to replace part of Ni element and reduce the cost.By means of thermal simulation,X-ray diffraction,field emission scanning electron microscopy,and electron backscattered diffraction,the effects of nanoceramic additives on high-temperature mechanical properties and corrosion behavior of the 310S steel were studied.The results indicate that the morphology and density of the(Fe,Cr)_(23)C_(6)carbides are varied,which play an important role in the high-temperature mechanical properties and corrosion behavior.After adding nano-ceramic additives,the high-temperature tensile strength and yield strength are improved simultaneously,in spite of a slight decrease in the total elongation.During high-temperature corrosion process,the mass gain of all the samples is parabolic with time.The mass gain is increased in the 310S steel with nano-ceramic additive,while the substrate thickness is significantly larger than 310S steel.The more stable and adherent FeCr_(2)O_(4)spinel form is the reason why the high-temperature corrosion resistance was increased.The(Fe,Cr)_(23)C_(6)carbides distribution along grain boundaries is detrimental to the high-temperature corrosion resistance.展开更多
基金The authors gratefully acknowledge the financial support from the National Natural Science Foundation of China(Nos.52274372 and 52201101)the National Key R&D Program of China(No.2021YFB3702404)the Fundamental Research Funds for the Central Universities(No.FRF-TP-22-013A1).
文摘This work investigated the effect of Cr and Si on the mechanical properties and oxidation resistance of press hardened steel.Results indicated that the microstructure of the Cr-Si micro-alloyed press hardened steel consisted of lath martensite,M_(23)C_(6)carbides,and retained austenite.The retained austenite and carbides are responsible for the increase in elongation of the micro-alloyed steel.In addition,after oxidation at 930℃for 5 min,the thickness of the oxide scales on the Cr-Si micro-alloyed press hardened steel is less than 5μm,much thinner than 45.50μm-thick oxide scales on 22MnB5.The oxide scales of the Cr-Si micro-alloyed steel are composed of Fe_(2)O_(3),Fe_(3)O_(4),mixed spinel oxide(FeCr_(2)O_(4)and Fe_(2)SiO_(4)),and amorphous SiO_(2).Adding Cr and Si significantly reduces the thickness of the oxide scales and prevents the generation of the FeO phase.Due to the increase of spinel FeCr_(2)O_(4)and Fe_(2)SiO_(4)phase in the inner oxide scale and the amorphous SiO_(2)close to the substrate,the oxidation resistance of the Cr-Si micro-alloyed press hardened steel is improved.
基金supported by Longyuan Youth Innovation and Entrepreneurship Talent Individual Project of Gansu Province in 2023 (Zhu Rong)Innovative Development Special Project of China Meteorological Administration (CXFZ2023J040)Science and Technology Plan Project of Gansu Province (22JR4ZA103)
文摘Development of urban human settlement environments(HSEs)is an integral part of promoting high-quality and sustainable regional development and constructing a beautiful China.The city of Lanzhou,located at the geometric center of China,is the only provincial capital traversed by the Yellow River.Given the constraints posed by the valley topography and the need for economic development,the development of this HSE,which is located within an arid region,poses considerable challenges.Evidently,an understanding of the evolution of HSEs and drivers of changes in them contributes to high-quality,sustainable urban development in arid and semi-arid regions.An analytical model was developed using the parameters of relief degree of land surface,human comfort days,the land cover index,nighttime light index,and precipitation.This model was used in combination with population density and the gross domestic product to analyze the spatial distribution of Lanzhou's HSE and its drivers.The results showed that landscapes in Lanzhou underwent significant changes between 2000 and 2022,with an increase in building-up land(+0.946%),cultivated land(+0.134%),and forest land(+0.018%)and a decrease in grassland(-1.10%).There was significant outward expansion of the main urban zone of Lanzhou and of various county towns,with the increase in building-up land being most prominent.During this period,there were significant changes in the periphery of the core urban area and county towns in Lanzhou,with decreases moving from the urban center(the highest value)to the surrounding areas(Yongdeng County had the lowest value).The correlation between the HSE and population density grew stronger in Anning and Chengguan Districts but became weaker in Xigu and Qilihe Districts.Spatiotemporal variations in the HSE were primarily caused by climate change,followed by human activities,and were also influenced by the valley topography.Overall,the spatial distribution of population density and the HSE in Lanzhou demonstrated good consistency under the in-fluence of economic development and urbanization.
基金supported by the National Natural Science Foundation of China(No.51674021)the Major Science and Technology Innovation Project of Shandong Province,China(No.2019JZZY010358)。
基金This work was financially supported by the National Natural Science Foundation of China(Nos.51334001,51674021,51574021,and 51734003).
文摘In last decade,the utilization of CO?resources in steelmaking has achieved certain metallurgical effects and the technology is maturing.In this review,we summarized the basic reaction theory of CO2,the CO2 conversion,and the change of energy-consumption when CO2 was introduced in converter steelmaking process.In the CO2-O2 mixed injection(COMI)process,the CO2 conversion ratio can be obtained as high as 80%or more with a control of the CO2 ratio in mixture gas and the flow rate of CO2,and the energy is saving and even the energy consumption can be reduced by 145.65 MJ/t under certain operations.In addition,a complete route of CO2 disposal technology is proposed combining the comparatively mature technologies of CO2 capture,CO2 compression,and liquid CO2 storage to improve the technology of CO2 utilization.The results are expected to form a large-scale,highly efficient,and valuable method to dispose of CO2.
文摘AIM: To evaluate the role of probiotics in the standard triple Helicobacter pylori therapy. METHODS: In this meta-analysis, we investigated the efficacy of probiotics in a standard triple H. pylori therapy in adults. Searches were mainly conducted in MEDLINE/PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials. Fourteen studies met our criteria, and the quality of these studies was assessed using the Jadad scale. We used STATA version 12.0 to extract data and to calculate the odds ratios (ORs), which are presented with the corresponding 95% confidence intervals (CIs). The data are presented as forest plots. RESULTS: The pooled ORs for the eradication rates calculated by intention-to-treat analysis and per-protocol analysis in the probiotic group vs the control group were 1.67 (95%CI: 1.38-2.02) and 1.68 (95%CI: 1.35-2.08), respectively, using the fixed-effects model. The sensitivity of the Asian studies was greater than that of the Caucasian studies (Asian: OR = 1.78, 95%CI: 1.40-2.26; Caucasian: OR = 1.48, 95%CI: 1.06-2.05). The pooled OR for the incidence of total adverse effects was signi.cantly lower in the probiotic group (OR = 0.49, 95%CI: 0.26-0.94), using the random effects model, with significant heterogeneity (I-2 = 85.7%). The incidence of diarrhea was significantly reduced in the probiotic group (OR = 0.21, 95%CI: 0.06-0.74), whereas the incidence of taste disorders, metallic taste, vomiting, nausea, and epigastric pain did not differ significantly between the probiotic group and the control group. CONCLUSION: Supplementary probiotic preparations during standard triple H. pylori therapy may improve the eradication rate, particularly in Asian patients, and the incidence of total adverse effects. (C) 2014 Baishideng Publishing Group Inc. All rights reserved.
基金supported by the New Century Excellent Talents Program of the Ministry of Education of China (No.NCET 07-0067)the National Natural Science Foundation of China (No.50874014)
文摘The process model for BOF process can be applied to predict the liquid steel composition and bath temperature during the whole steelmaking process. On the basis of the traditional three-stage decarburization theory, the concept of mixing degree was put forward, which was used to indicate the effect of oxygen jet on decarburization. Furthermore, a more practical process model for BOF steelmaking was developed by analyzing the effect of silicon, manganese, oxygen injection rate, oxygen lance height, and bath temperature on decarburization. Process verification and end-point verification for the process model have been carried out, and the verification results show that the predic- tion accuracy of carbon content reaches 82.6% （the range of carbon content at the end-point is less than 0. 1wt%） and 85.7% （the range of carbon content at end-point is 0. 1wt% -0.7wt%） when the absolute error is less than 0.02wt% and 0.05wt%, respectively.
文摘A three-dimensional computational fluid dynamics （CFD） model was developed to simulate a 150-t top-blown converter. The ef-fect of different lance heights on the cavity shape was investigated using the volume of fluid （VOF） method. Numerical simulation results can reflect the actual molten bath surface waves impinged by the supersonic oxygen jets. With increasing lance height, the cavity depth de-creases, and the cavity area, varying like a parabola, increases and then decreases. The cavity area maximizes at the lance height of 1.3 m. Under the three different lance heights simulated in this study, all of the largest impact velocities at the molten bath surface are between 50 m/s and 100 m/s.
基金financially supported by the Fujian Province Foundation of Strategic Emerging Industry Projects(No.2014H0023)the Fuzhou University Foundation for Development of Science and Technology(No.2012-XQ-19)
文摘A new environment-friendly free-cutting steel alloyed with elemental Sn （Y20Sn） was developed to meet the requirements of machinability and mechanical properties according to GB/T8731--1988. The machinability of the steel is enhanced by the segregation of elemental Sn at grain boundaries. The effect of Sn segregation on intergranular brittle fracture at normal cutting temperature from 250℃ to 400℃ is confirmed. The formation mechanism of main inclusions MnS is influenced by the presence of Sn and the attachment of Sn around MnS itself as a surfactant, and this mechanism also explains the improvement in machinability and mechanical properties of the steel. In the steel, the relevant inclusions are mainly spherical or axiolitic, and are uniformly distributed in small volume. Such inclusions improve the machinability of the steel and do not impair the mechanical properties as well. Experimental results demonstrate that the appropriate content of Sn in the steel is 0.03wt% to 0.08wt%, and the remaining composition is close to that of standard Y20 steel.
基金financially supported by the National Natural Science Foundation of China (Nos. 51474024, 51674021, and 51574021)
文摘Herein, a multi-index analysis of the nickel content of an alloy, output rate of the alloy, nickel recovery rate, and iron recovery rate during the melting of laterite metallized pellets was performed. The thermodynamic reduction behavior of oxides such as NiO, FeO, Fe_3 O_4, and Cr_2 O_3 was studied using the FactSage software, which revealed that SiO_2 is not conducive to the reduction of iron oxides, whereas the addition of basic oxides such as CaO and MgO is beneficial for the reduction of iron oxides. On the basis of a comprehensive analysis to achieve greater nickel recovery and lower iron recovery rates, the optimum experimental parameters in the orthogonal experiment were A3 B1 C3(t = 30 min, C/O = 0.4, R = 1.2); the indicators wNi, φalloy, ηNi, and ηFe had values of 15.0 wt%, 12.1%, 44.9%, and 96.4%, respectively. In single-factor experiments, increasing basicity(R) substantially improved the separation effect in the low-basicity range 0.5 ≤ R ≤ 0.8 but not in the high-basicity range 0.8 ≤ R ≤ 1.2. Similar results were obtained for the effect of the C/O ratio. Moreover, the recovery rate of nickel increased with increasing recovery rate of iron.
基金supported by National Key Technology Research and Development Program (No 2008BAC35B02)
文摘Observations of the Langmuir Probe Instrument （ISL, Instrument Sonde de Langmuir） onboard the DEMETER satellite during four years from 2006 to 2009 were used to analyze the tempo-spatial variations of electron density （Ne） and temperature （Te） in the ionosphere. Twenty four research bins with each covering an area with 10° in longitude and 2° in latitude were selected to study the spatial distributions of Ne and Te. The results indicate that both Ne and Te have strong an- nual variations in the topside ionosphere at 660 krn altitude. The semiannual anomaly and equinoctial asymmetry which are usually well known as the features of F-layer also exist in the topside ionosphere at low- and mid-latitudes. The yearly varia- tion of No is opposite to the peak electron density of the F2-1ayer （NmF2） at higher latitudes in daytime and both are similar in nighttime. Also the yearly variations of Tc at low-latitude are contrary to that at 600 km in daytime and similar in nighttime An interesting feature of nighttime Te at low-latitude is an obvious annual variation in the northern hemisphere and semian- nual variation in the southern hemisphere. The yearly variations of Te in daytime have negative and positive correlation with Ne at mid- and high-latitudes, respectively. Both Nc and Te in the neighborhood bins at the same latitude have a high correlation. In ionospheric events analyzing, this information may help to understand the characteristics of the variation and to dis- tinguish the reliable abnormality from the normal background map.
基金Supported by the Lanzhou Science and Technology Plan Project,No.2018-3-48Lanzhou Talent Innovation and Entrepreneurship Project,No.2019-RC-35and 2019 Special Fund for Doctoral Training of Lanzhou University Second Hospital,No.YJS-BD-15.
文摘BACKGROUND Primary Sjögren's syndrome(pSS)concomitant with autoimmune hemolytic anemia(AIHA)but without eye and mouth dryness is exceedingly rare.Iguratimod(IGU)has been widely used in the treatment of pSS.However,there are few reports about the application of IGU in pSS concomitant with AIHA.CASE SUMMARY Here,we present the case of a patient with pSS concomitant with AIHA but without eye and mouth dryness.The patient was initially diagnosed with hyperplastic anemia and AIHA while pSS was missed,and was finally diagnosed with pSS concomitant with AIHA.The patient was treated with IGU along with prednisone and hydroxychloroquine,and her hemoglobin,reticulocytes and IgG returned to normal levels.CONCLUSION IGU was effective for and well tolerated by our patient with pSS concomitant with AIHA,and may be a promising therapy for the treatment of this disease.
文摘Takayasu arteritis (TA) is a chronic, nonspecific inflammatory disease of large and medium-sized vessels that primarily involves the aorta and its branches. TA involving the pulmonary arteries has a prevalence ranging from 14% to 86%, which can lead to pulmonary hypertension, a progressive increase in pulmonary artery pressure, and eventually death from right heart failure. The presentation of pulmonary arteritis (PA) is very nonspecific, with a reported misdiagnosis rate of up to 60% and a diagnosis time ranging from 1 month to more than 10 years. The clinical manifestation of pleural effusion is very rare in both TA and PA cases. Based on our literature review, this is the 6th reported case of TA with pleural effusion, and the specific mechanism of TA with pleural effusion is still unclear. The characteristics of this case and the previously reported cases are summarized in this article to improve the understanding of TA and PA and reduce the misdiagnosis rate.
基金financially supported by Fundamental Research Funds for the Central Universities (No. FRF-GF18-008B)
文摘Based on a current coherent jet,this study proposes a supersonic combustion(SC)coherent jet in which the main oxygen jet is surrounded by a supersonic fuel gas.The characteristics of the proposed coherent jet are analyzed using experimental methods and numerical simulations in the high-temperature environment of electric arc furnace(EAF)steelmaking.The SC coherent jet achieved stable combustion in the EAF steelmaking environment.The simulated combustion temperature of the supersonic shrouding methane gas was 2930 K,slightly below the theoretical combustion temperature of methane–oxygen gas.The high speed and temperature of the supersonic flame effectively weakened the interaction between the main oxygen jet and the external ambient gas,inhibiting the radial expansion of the main oxygen jet and maintaining its high speed and low turbulence over a long distance.These features improved the impact capacity of the coherent jet and strengthened the stirring intensity in the EAF bath.
基金National natural science foundation of China(No.81660649)Innovation and entrepreneurship training program for undergraduates of Hainan medical university in 2019(No.X201911810073)。
文摘Objective:To make Galangin-PLGA nanoparticles(GL-PLGA NPs)were prepared using the biodegradable material polylactic-coglycolic acid(PLGA)as the carrier material,and the formulation was optimized.Methods:Nanoparticles were prepared by modified emulsification-solvent evaporation method and the content of galangin was determined by HPLC.With particle size and entrapment efficiency as the indexes,single factor and orthogonal test were used to optimize the formulation,and the quality of the optimized GL-PLGA NPs was evaluated from the surface configuration,particle size distribution,Zeta potential and entrapment efficiency.Results:The optimal prescription conditions of GL-PLGA NPs were:the volume ratio of organic phase to aqueous phase was 1:8,the concentration of PVA was 1.5%,the concentration of PLGA was 1.0%,and the drug concentration was 0.2%.Under these conditions,the average particle size of GL-PLGA NPs was 249±1.32nm,polydispersity index(PDI)was 0.059,Zeta potential was-4.86mV,and the entrapment efficiency was 75.3%.The results of electron microscopy showed that the nanoparticles were spherical,uniform particle size and good dispersion.Conclusion:The preparation method is simple and stable,and GL-PLGA NPs with suitable particle size and high entrapment efficiency can be obtained.
基金the National Natural Science Foundation of China(Nos.52204342 and 52201073)Natural Science Foundation of Hebei Province(No.E2022208019)+1 种基金Natural Science Foundation of Hebei Education Department(Nos.BJK2024194 and BJK2024024)Natural Science Foundation of Hebei Education Department(No.QN2021058)for financial support.
文摘Energy-saving in China's iron and steel industry still relies on the development and improvement of short-term energy saving technologies.Therefore,a special converter smelting technology incorporating energy saving was proposed.To evaluate the energy-saving potential of the CO_(2)–O_(2)mixed injection(COMI)technology,collected production data were used to develop an improved techno-economic model.Calculations reveal that the technology can save energy through auxiliary material consumption,sensible heat of solid by-product,iron loss reduction,and energy recovery.The application of COMI technology in an enterprise is cost effective,involving the energy saving potential of 0.206 GJ/t,the cost of conserved energy of−48.83 yuan/GJ,and a simple payback period of 0.35 year for a 60-million-yuan investment.Sensitivity analysis shows that the investment cost and discount rate primarily influence the cost of conserved energy of the technology.As the discount rate increased,the cost of conserved energy also gradually increased.Overall,the COMI technology is an energy-saving technology with good development prospects.
基金supported by the National Natural Science Foundation of China(grant nos.51735007 and 62003184)the Beijing Natural Science Foundation(3191001).
文摘Comprehensive and quantitative assessment of human physical activity in daily life is valuable for healthcare,especially for those who suffer from obesity and neurological disorders or are at high risk of dementia.Common wearable devices,e.g.,smartwatches,are insufficient and inaccurate for monitoring highly dynamic limb movements and assessing human motion.Here,we report a new wearable leg movement monitoring system incorporating a custom-made motion sensor with machine learning algorithm to perceive human motion accurately and comprehensively during diverse walking and running actions.The system enables real-time multimodal perceptions of personal identity,motion state,locomotion speed,and energy expenditure for wearers.A general law of extracting real-time metabolic energy from leg movements is verified although individual gaits show differences.In addition,we propose a novel sensing configuration combining unilateral lower leg movement velocity with its angular rate to achieve high accuracy and good generalizability while simplifying the wearable system.Advanced performances in personal identification(accuracy of 98.7%)and motion-state recognition(accuracy of 93.7%)are demonstrated.The wearable system also exhibites high-precision real-time estimations of locomotion speed(error of 3.04%to 9.68%)and metabolic energy(error of 4.18%to 14.71%)for new subjects across various time-varying conditions.The wearable system allows reliable leg movement monitoring and quantitative assessment of bodily kinematic and kinetic behaviors during daily activities,as well as safe identity authentication by gait parameters,which would greatly facilitate smart life,personal healthcare,and rehabilitation training.
基金This work was financially supported by the Key Technology Research and Development Program of Shandong(2019TSLH0103)the Fundamental Research Funds for the Central Universities(FRF-TP-19-009A1).
文摘A novel approach to reduce Ni content for the 310S austenitic stainless steel was proposed.The nano-ceramic additive(L)was applied to 310S steel to replace part of Ni element and reduce the cost.By means of thermal simulation,X-ray diffraction,field emission scanning electron microscopy,and electron backscattered diffraction,the effects of nanoceramic additives on high-temperature mechanical properties and corrosion behavior of the 310S steel were studied.The results indicate that the morphology and density of the(Fe,Cr)_(23)C_(6)carbides are varied,which play an important role in the high-temperature mechanical properties and corrosion behavior.After adding nano-ceramic additives,the high-temperature tensile strength and yield strength are improved simultaneously,in spite of a slight decrease in the total elongation.During high-temperature corrosion process,the mass gain of all the samples is parabolic with time.The mass gain is increased in the 310S steel with nano-ceramic additive,while the substrate thickness is significantly larger than 310S steel.The more stable and adherent FeCr_(2)O_(4)spinel form is the reason why the high-temperature corrosion resistance was increased.The(Fe,Cr)_(23)C_(6)carbides distribution along grain boundaries is detrimental to the high-temperature corrosion resistance.
