Colorectal cancer(CRC)belongs to the class of significantly malignant tumors found in humans.Recently,dysregulated fatty acid metabolism(FAM)has been a topic of attention due to its modulation in cancer,specifically C...Colorectal cancer(CRC)belongs to the class of significantly malignant tumors found in humans.Recently,dysregulated fatty acid metabolism(FAM)has been a topic of attention due to its modulation in cancer,specifically CRC.However,the regulatory FAM pathways in CRC require comprehensive elucidation.Methods:The clinical and gene expression data of 175 fatty acid metabolic genes(FAMGs)linked with colon adenocarcinoma(COAD)and normal cornerstone genes were gathered through The Cancer Genome Atlas(TCGA)-COAD corroborating with the Molecular Signature Database v7.2(MSigDB).Initially,crucial prognostic genes were selected by uni-and multi-variate Cox proportional regression analyses;then,depending upon these identified signature genes and clinical variables,a nomogram was generated.Lastly,to assess tumor immune characteristics,concomitant evaluation of tumor immune evasion/risk scoring were elucidated.Results:A 8-gene signature,including ACBD4,ACOX1,CD36,CPT2,ELOVL3,ELOVL6,ENO3,and SUCLG2,was generated,and depending upon this,CRC patients were categorized within high-risk(H-R)and low-risk(L-R)cohorts.Furthermore,risk and age-based nomograms indicated moderate discrimination and good calibration.The data confirmed that the 8-gene model efficiently predicted CRC patients’prognosis.Moreover,according to the conjoint analysis of tumor immune evasion and the risk scorings,the H-R cohort had an immunosuppressive tumor microenvironment,which caused a substandard prognosis.Conclusion:This investigation established a FAMGs-based prognostic model with substantially high predictive value,providing the possibility for improved individualized treatment for CRC individuals.展开更多
Background:Skin aging has recently gained significant attention in both society and skin care research.Understanding the biological processes of photoaging caused by long-term skin exposure to ultraviolet radiation is...Background:Skin aging has recently gained significant attention in both society and skin care research.Understanding the biological processes of photoaging caused by long-term skin exposure to ultraviolet radiation is critical for preventing and treating skin aging.Therefore,it is important to identify genes related to skin photoaging and shed light on their functions.Methods:We used data from the Gene Expression Omnibus(GEO)database and conducted bioinformatics analyses to screen and extract microRNAs(miRNAs)and their downstream target genes related to skin photoaging,and to determine possible biological mechanisms of skin photoaging.Results:A total of 34 differentially expressed miRNAs and their downstream target genes potentially related to the biological process of skin photoaging were identified.Gene Ontology enrichment analysis and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis showed that these target genes were enriched in pathways related to human papillomavirus infection,extracellular matrix(ECM)-receptor signaling,estrogen receptor,skin development,epidermal development,epidermal cell differentiation,keratinocyte differentiation,structural components of the ECM,structural components of the skin epidermis,and others.Conclusion:Based on the GEO database-derived findings,we determined that target genes of two miRNAs,namely miR-4667-5P-KRT79 and miR-139-5P-FOS,play an important role in skin photoaging.These observations could provide theoretical support and guidance for further research on skin aging-related biological processes.展开更多
Eastern Qinling,China is one of the important rare metal metallogenic provinces with extensively distributed granite pegmatite dikes.The No.5 granite pegmatite intruded into the granitic gneiss of the Qinling Group,an...Eastern Qinling,China is one of the important rare metal metallogenic provinces with extensively distributed granite pegmatite dikes.The No.5 granite pegmatite intruded into the granitic gneiss of the Qinling Group,and the major minerals are quartz(39.8%),K-feldspar(18.8%),albite(36.3%),muscovite(3.4%),and garnet(1.1%).Monazite U–Pb isotopic dating indicates that the No.5 pegmatite from the Eastern Qinling was emplaced at ca.420.2±2.2 Ma,which confirms that highpurity quartz mineralization probably formed during the Early Devonian.In-situ laser ablation inductively coupled plasma mass spectrometry analysis of quartz show that quartz samples from Eastern Qinling have total trace element concentrations(Al,Ti,Sc,Li,B,Cr,Mn,and Fe)ranging from 23.2 to 52.8 ppm,slightly higher than the quartz(impurity element content from 13.4 to 25.9 ppm)of the Spruce Pine high-purity quartz deposit in western North Carolina.The No.5 pegmatite of Eastern Qinling could be defined as one high-purity quartz deposit of China.展开更多
Calcium sulfate(CaSO_(4))has been verified as a promising oxygen carrier(OC)in the chemical looping combustion(CLC)for its high oxygen capacity,abundant reserve and low cost,but its low reactivity and deleterious sulf...Calcium sulfate(CaSO_(4))has been verified as a promising oxygen carrier(OC)in the chemical looping combustion(CLC)for its high oxygen capacity,abundant reserve and low cost,but its low reactivity and deleterious sulfur species emission from the side reactions of CaSO_(4) should be well considered for its wide application in CLC.In order to promote the reactivity of CaSO_(4) and increase its potential to inhibit the gaseous sulfur emission,a CeO_(2)-enhanced CaSO_(4) OC mixed OC of core–shell structure was prepared using the combined template synthesis method.Reaction characteristics of the prepared CaSO_(4)-CeO_(2) mixed OC with a typical lignite was first conducted and systematically investigated,and an improved reactivity of the prepared CaSO_(4)-CeO_(2) mixed OC was demonstrated than its single component CaSO_(4) or CeO_(2) due to the fast transfer and exchange of oxygen from the CaSO_(4) substrate to coal via the doped CeO_(2).Furthermore,the solid products formed from the mixed CaSO_(4)-CeO_(2) OC with the selected coal were collected and analyzed.Especially,evolution and redistribution of the sulfur species of different forms were focused.At the latter reaction stage of YN reaction with the CaSO_(4)-CeO_(2) mixed OC,the SO_(2) emitted from the side reactions of CaSO_(4) was greatly diminished and the doped CeO_(2) was proven effective to directionally fix the SO_(2) released to turn into different solid sulfur compounds,which were determined as Ce_(2)O_(2)S,Ce_(2)S_(3) and Ce_(2)(SO_(4))_(3)·5H_(2)O and formed through the different pathways.In addition,good regeneration of the reduced CaSO_(4)-CeO_(2) mixed OC could be reached in spite of the unavoidable interaction between the included minerals in coal and the reduced mixed OC.Overall,the combined template method-made CaSO_(4)-CeO_(2) mixed OC reported herein was not only endowed with enhanced reactivity for coal conversion,but also owned the potential to directionally fix the gaseous sulfur emission,which is quite applicable as OC for simultaneous decarbonatization and desulfurization in the real CLC process.展开更多
This work presents a simulation study of several Ca-Cu looping variants with CO(2)capture,aiming at both parameter optimization and exergy analysis of these Ca-Cu looping systems.Three kinds of Ca-Cu looping are consi...This work presents a simulation study of several Ca-Cu looping variants with CO(2)capture,aiming at both parameter optimization and exergy analysis of these Ca-Cu looping systems.Three kinds of Ca-Cu looping are considered:(1)carbonation-calcination/reduction-oxidation;(2)carbonation-oxidation-calcination/reduction and (3)carbona tion/oxidation-calcination/reduction.A conventional Ca looping is also simulated for comparison.The influences of the calcination temperature on the mole fractions of CO(2)and CaO at the calciner outlet,the CaCO3 flow rate on the carbonator performance and the Cu/Ca ratio on the calciner performance are analyzed.The second kind of Ca-Cu looping has the highest carbonation conversion.At 1×10^5 Pa and 820℃,complete decomposition of CaCO3 can be achieved in three Ca-Cu looping systems,while the operation condition of 1×10^5 Pa,840℃is required for the conventional Ca looping system.Furthermore,the Cu/Ca molar ratio of 5.13-5.19 is required for the Ca-Cu looping.Exergy analyses show that the maximum exergy destruction occurs in the calciner for the four modes and the second Ca-Cu looping system(i.e.,carbonation-oxidation-calcination/reduction)performs the highest exergy efficiency,up to 65.04%,which is about 30%higher than that of the conventional Ca looping.展开更多
Objectives:Reported prediction rules for postoperative atrial fibrillation(AF)have suffered from inconsistent results and controversy surrounding the predictive value of a preoperative P-wave duration(PreOPWD).This st...Objectives:Reported prediction rules for postoperative atrial fibrillation(AF)have suffered from inconsistent results and controversy surrounding the predictive value of a preoperative P-wave duration(PreOPWD).This study examined PreOPWD as a predictor for AF after coronary artery bypass grafting(CABG).Methods:Two-hundred-and-ninety-nine patients with sinus rhythm before off-pump CABG were recruited into the study.Patients'demographic and clinical data were evaluated prospectively.Patients were continuously monitored for the first seven postoperative days.Multiple logistic regressionwas used to determine significant predictors of AF.Findings were then combined with similar studies and a metaanalysis was performed.Results:Postoperative AF was observed in 33.1%of 299 patients.Patients with AF were older,had a prolonged PreOPWD,higher incidences of hypertension,aortic regurgitation,and mitral regurgitation.A cut-off point of PreOPWD105ms achieved a specificity of 74%,and a sensitivity of 65%for predictive of AF.Multivariate analysis showed that PreOPWD105ms(odds ratio[OR]4.63,95%confidence intervals[CI]2.66 to 8.03,P<0.001),age60 years(OR 2.72,95%CI 1.51 to 4.90,P<0.01)and hypertension(OR 2.10,95%CI 1.08 to 4.07,P<0.05)independently predicted postoperative AF.A meta-analysis of this data combined with those of ten other studies showed that PreOPWD was greater in patients with POAF,with a weighted mean difference of 3.95 ms(95%CI 1.97 to 5.92,P<0.001).Conclusion:This study confirmed,among other predictive characteristics,that PreOPWD is a powerful independent predictor of POAF.展开更多
Under the condition of simulated formation temperature and pressure, the compression and shear wave velocity of the tuffaceous conglomerates and rock-fragment sandstones of the reservoirs in K1t, k1n group of Cretaceo...Under the condition of simulated formation temperature and pressure, the compression and shear wave velocity of the tuffaceous conglomerates and rock-fragment sandstones of the reservoirs in K1t, k1n group of Cretaceous system in Tanan are measured. The effects of lithology, mineral content, density, porosity, shale content, and water saturation on the acoustic velocity of the athrogenic rock are studied. Within the limits of our observation, some rules are found: (1) the velocity of the fine tuffaceous conglomerates is remarkably greater than that of the tuffaceous rock-fragment sandstones with good physical property;(2) the compression velocity increases with fragment content, and decreases with quartz and feldspar content in the mud;(3) the compression velocity increases with density, especially, in tuffaceous rock-fragment sandstones, the velocity keeps a good relation with density in form of power function;(4) compression and shear wave velocity decreases with porosity and shale content, velocity of the tuffaceous rock-fragment sandstones keeps a good relation with porosity and shale content in form of negative linear function, but effects of shale content is only 1/5 to 1/10 of that of the porosity, hence can be neglected;(5) with porosity increases, compression wave velocity is relatively sensitive to fluid alternation, and the rang in which velocity varies keeps positive correlation with porosity. The result provides a foundation for the research of seismic and logging data evaluation approaches in athrogenic rock reservoirs, Haita basin.展开更多
In this study, polymorphisms of the DGAT1 andSTAT5A genes were detected in 528 individuals from Xinong Saanen and Guanzhong goat breeds by PCR-RFLP, PCR-SSCP and DNA sequencing methods. Three allelic variants were ide...In this study, polymorphisms of the DGAT1 andSTAT5A genes were detected in 528 individuals from Xinong Saanen and Guanzhong goat breeds by PCR-RFLP, PCR-SSCP and DNA sequencing methods. Three allelic variants were identified: DQ380250: g.407_408insC, AJ237937: g.6798C>T and g.6852C>T in both breeds. At g.407_408insC locus, the frequencies of C1 allele were 0.79–0.85, and frequencies of C2 allele were 0.21–0.15. At g.6852C>T locus, frequencies of C3 allele were 0.70–0.72, and frequencies of T3 allele were 0.30–0.28. Compared with goats with C1C1 and C3C3, those with C1C2 and C3T3 genotypes had significant effects on milk yield and fat percentage (P<0.05), respectively. The result showed that does with C1C1C3T3 and C1C2C3T3 had higher milk yield than those with C1C2C3C3 (P < 0.05). In addition, the combined effect of C1C2C3C3 on milk fat percentage was the highest in comparison with other combination genotypes (P<0.05).展开更多
The mechanism and characteristics of spectral polarization imaging technique are presented. The present research and developing trend of spectral polarization remote sensing are introduced. A novel method of spectral ...The mechanism and characteristics of spectral polarization imaging technique are presented. The present research and developing trend of spectral polarization remote sensing are introduced. A novel method of spectral polarization imaging technique is discussed, which is based on static intensity modulation adding with double refraction crystal spectrometer. The static intensity modulation consists of two retarders and one polarizer. The double refraction crystal is used to generate interference image. The spectral and four Stokes vectors information can be obtained only by one measurement. The method of static intensity modulation is deduced in detail and is simulated by computer. The spectropolarimeter experimental system is also established in the laboratory. The basic concept of the technique is verified.展开更多
Given the difficulty in accurately evaluating the fatigue performance of large composite wind turbine blades(referred to as blades),this paper takes the main beam structure of the blade with a rectangular cross-sectio...Given the difficulty in accurately evaluating the fatigue performance of large composite wind turbine blades(referred to as blades),this paper takes the main beam structure of the blade with a rectangular cross-sectionas the simulation object and establishes a composite laminate rectangular beam structure that simultaneouslyincludes the flange,web,and adhesive layer,referred to as the blade main beam sub-structure specimen,throughthe definition of blade sub-structures.This paper examines the progressive damage evolution law of the compositelaminate rectangular beam utilizing an improved 3D Hashin failure criterion,cohesive zone model,B-K failurecriterion,and computer simulation technology.Under static loading,the layup angle of the anti-shear web hasa close relationship with the static load-carrying capacity of the composite laminate rectangular beam;under fatigueloading,the fatigue damage will first occur in the lower flange adhesive area of the whole composite laminaterectangular beam and ultimately result in the fracture failure of the entire structure.These results provide a theoreticalreference and foundation for evaluating and predicting the fatigue performance of the blade main beamstructure and even the full-size blade.展开更多
In gas-solid flows, particle-particle interaction (typical, particle collision) is highly significant, despite the small particles fractional volume. Widely distributed polydisperse particle population is a typical ...In gas-solid flows, particle-particle interaction (typical, particle collision) is highly significant, despite the small particles fractional volume. Widely distributed polydisperse particle population is a typical characteristic during dynamic evolution of particles (e.g., agglomeration and fragmentation) in spite of their initial monodisperse particle distribution. The conventional direct simulation Monte Carlo (DSMC) method for particle collision tracks equally weighted simulation particles, which results in high statistical noise for particle fields if there are insufficient simulation particles in less-populated regions. In this study, a new differentially weighted DSMC (DW-DSMC) method for collisions of particles with different number weight is proposed within the framework of the general Eulerian-Lagrangian models for hydrodynamics. Three schemes (mass, momentum and energy conservation) were developed to restore the numbers of simulation particle while keeping total mass, momentum or energy of the whole system unchanged respectively. A limiting case of high-inertia particle flow was numerically simulated to validate the DW-DSMC method in terms of computational precision and efficiency. The momentum conservation scheme which leads to little fluctuation around the mass and energy of the whole system performed best. Improved resolution in particle fields and dynamic behavior could be attained simultaneously using DW-DSMC, compared with the equally weighted DSMC. Meanwhile, computational cost can be largely reduced in contrast with direct numerical simulation.展开更多
Chemical looping combustion (CLC) of coal has gained increasing attention as a novel combustion technology for its advantages in CO2 capture. Sulfur evolution from coal causes great harm from either the CLC operatio...Chemical looping combustion (CLC) of coal has gained increasing attention as a novel combustion technology for its advantages in CO2 capture. Sulfur evolution from coal causes great harm from either the CLC operational or environmental perspective. In this research, a combined MnFe2O4 oxygen carrier (OC) was synthesized and its reaction with a typical Chinese high sulfur coal, Liuzhi (LZ) bituminous coal, was performed in a thermogravimetric analyzer (TGA)-Fourier transform infrared (FT-IR) spectrometer. Evolution of sulfur species during reaction of LZ coal with MnFeaO40C was systematically investigated through experimental means combined with thermodynamic simulation. TGA-FTIR analysis of the LZ reaction with MnFe2O4 indicated MnFe2O4 exhibited the desired superior reactivity compared to the single reference oxides Mn304 or Fe203, and SO2 produced was mainly related to oxidization of H2S by MnFe2O4. Experimental analysis of the LZ coal reaction with MnFe2O4, including X-ray diffraction and X-ray photoelectron spectroscopy analysis, verified that the main reduced counterparts of MnFe2O4 were Fe304 and MnO, in good agreement with the related thermodynamic simulation. The obtained MnO was beneficial to stabilize the reduced MnFe2O4 and avoid serious sintering, although the oxygen in MnO was not fully utilized. Meanwhile, most sulfur present in LZ coal was converted to solid MnS during LZ reaction with MnFe2O4, which was further oxidized to MnSO4. Finally, the formation of both MnS and such manganese silicates as Mn2SiO4 and MnSiO3 should be addressed to ensure the full regeneration of the reduced MnFe2O4.展开更多
Recently,two-dimensional MXene materials have attracted numerous attention in electromagnetic wave shielding/absorption.Hybridizing magnetic materials and constructing multi-dimensional structures in MXene is highly b...Recently,two-dimensional MXene materials have attracted numerous attention in electromagnetic wave shielding/absorption.Hybridizing magnetic materials and constructing multi-dimensional structures in MXene is highly beneficial to improve electromagnetic wave absorption properties.Herein,we demonstrate a strategy for in situ growing 0 D CoNi nanoalloy-encapsulated 1 D N-doped carbon nanotubes on a2 D Ti_(3)C_(2)T_(x)MXene sheet through an electrostatic assembly process followed by a high-temperature pyrolysis process.The resultant 201-structured MXene-CoNi@N-doped carbon nanotube(MXene-CoNi@NCNT)composites displayed high surface areas(55.6-103.7 m^(2)/g),moderate magnetism(19.8-24.6 emu/g),and excellent thermal oxidation stabilities(≥ 307℃).In addition,the unique 2 D/0 D/1 D architectures entrusted the composites with abundant interfaces,various defects,and numerous nitrogen dopants.Taking advantage of the special 201 structure and the existence of both magnetic and dielectric loss,the MXeneCoNi@NCNT composite showed great impedance matching and strong attenuation performance.A strong reflection loss of-55.3 dB was achieved when the coating thickness was 2.1 mm,and a wide effective absorption bandwidth of 4.3 GHz was achieved at a thickness of 1.5 mm,much superior to that of similar absorbers.This work demonstrates a novel strategy for designing electromagnetic wave absorbers with magnetic and dielectric losses accompanied by multiple dimensional structures.展开更多
基金supported by the Doctoral Fund of Jining No.1 People’s Hospital(2021-BS-002).
文摘Colorectal cancer(CRC)belongs to the class of significantly malignant tumors found in humans.Recently,dysregulated fatty acid metabolism(FAM)has been a topic of attention due to its modulation in cancer,specifically CRC.However,the regulatory FAM pathways in CRC require comprehensive elucidation.Methods:The clinical and gene expression data of 175 fatty acid metabolic genes(FAMGs)linked with colon adenocarcinoma(COAD)and normal cornerstone genes were gathered through The Cancer Genome Atlas(TCGA)-COAD corroborating with the Molecular Signature Database v7.2(MSigDB).Initially,crucial prognostic genes were selected by uni-and multi-variate Cox proportional regression analyses;then,depending upon these identified signature genes and clinical variables,a nomogram was generated.Lastly,to assess tumor immune characteristics,concomitant evaluation of tumor immune evasion/risk scoring were elucidated.Results:A 8-gene signature,including ACBD4,ACOX1,CD36,CPT2,ELOVL3,ELOVL6,ENO3,and SUCLG2,was generated,and depending upon this,CRC patients were categorized within high-risk(H-R)and low-risk(L-R)cohorts.Furthermore,risk and age-based nomograms indicated moderate discrimination and good calibration.The data confirmed that the 8-gene model efficiently predicted CRC patients’prognosis.Moreover,according to the conjoint analysis of tumor immune evasion and the risk scorings,the H-R cohort had an immunosuppressive tumor microenvironment,which caused a substandard prognosis.Conclusion:This investigation established a FAMGs-based prognostic model with substantially high predictive value,providing the possibility for improved individualized treatment for CRC individuals.
基金supported by Zhejiang Provincial Natural Science Foundation of China(grant no.LQ22H150005)。
文摘Background:Skin aging has recently gained significant attention in both society and skin care research.Understanding the biological processes of photoaging caused by long-term skin exposure to ultraviolet radiation is critical for preventing and treating skin aging.Therefore,it is important to identify genes related to skin photoaging and shed light on their functions.Methods:We used data from the Gene Expression Omnibus(GEO)database and conducted bioinformatics analyses to screen and extract microRNAs(miRNAs)and their downstream target genes related to skin photoaging,and to determine possible biological mechanisms of skin photoaging.Results:A total of 34 differentially expressed miRNAs and their downstream target genes potentially related to the biological process of skin photoaging were identified.Gene Ontology enrichment analysis and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis showed that these target genes were enriched in pathways related to human papillomavirus infection,extracellular matrix(ECM)-receptor signaling,estrogen receptor,skin development,epidermal development,epidermal cell differentiation,keratinocyte differentiation,structural components of the ECM,structural components of the skin epidermis,and others.Conclusion:Based on the GEO database-derived findings,we determined that target genes of two miRNAs,namely miR-4667-5P-KRT79 and miR-139-5P-FOS,play an important role in skin photoaging.These observations could provide theoretical support and guidance for further research on skin aging-related biological processes.
基金the National Natural Science Foundation of China(42062006 and 41962007)the National Key Research and Development Program of China(2016YFC0600207)+1 种基金the Project of China Geological Survey(DD20190186 and 12120114034501)the science and technology research project of Jiangxi Provincial Department of Education(GJJ190379)。
文摘Eastern Qinling,China is one of the important rare metal metallogenic provinces with extensively distributed granite pegmatite dikes.The No.5 granite pegmatite intruded into the granitic gneiss of the Qinling Group,and the major minerals are quartz(39.8%),K-feldspar(18.8%),albite(36.3%),muscovite(3.4%),and garnet(1.1%).Monazite U–Pb isotopic dating indicates that the No.5 pegmatite from the Eastern Qinling was emplaced at ca.420.2±2.2 Ma,which confirms that highpurity quartz mineralization probably formed during the Early Devonian.In-situ laser ablation inductively coupled plasma mass spectrometry analysis of quartz show that quartz samples from Eastern Qinling have total trace element concentrations(Al,Ti,Sc,Li,B,Cr,Mn,and Fe)ranging from 23.2 to 52.8 ppm,slightly higher than the quartz(impurity element content from 13.4 to 25.9 ppm)of the Spruce Pine high-purity quartz deposit in western North Carolina.The No.5 pegmatite of Eastern Qinling could be defined as one high-purity quartz deposit of China.
基金supported by the National Natural Science Founda-tion of China(Nos.51776073,51906083)Key Research&Develop-ment program of Henan Province(No.162102210233)+1 种基金North China University of Water Resources and Electric Power Innovative Project(Nos.2019XA014,2019XB058)Scientific Research&Development Project of Ji-Yan Energy Science and Technology Research Institute(NKY2020-05).
文摘Calcium sulfate(CaSO_(4))has been verified as a promising oxygen carrier(OC)in the chemical looping combustion(CLC)for its high oxygen capacity,abundant reserve and low cost,but its low reactivity and deleterious sulfur species emission from the side reactions of CaSO_(4) should be well considered for its wide application in CLC.In order to promote the reactivity of CaSO_(4) and increase its potential to inhibit the gaseous sulfur emission,a CeO_(2)-enhanced CaSO_(4) OC mixed OC of core–shell structure was prepared using the combined template synthesis method.Reaction characteristics of the prepared CaSO_(4)-CeO_(2) mixed OC with a typical lignite was first conducted and systematically investigated,and an improved reactivity of the prepared CaSO_(4)-CeO_(2) mixed OC was demonstrated than its single component CaSO_(4) or CeO_(2) due to the fast transfer and exchange of oxygen from the CaSO_(4) substrate to coal via the doped CeO_(2).Furthermore,the solid products formed from the mixed CaSO_(4)-CeO_(2) OC with the selected coal were collected and analyzed.Especially,evolution and redistribution of the sulfur species of different forms were focused.At the latter reaction stage of YN reaction with the CaSO_(4)-CeO_(2) mixed OC,the SO_(2) emitted from the side reactions of CaSO_(4) was greatly diminished and the doped CeO_(2) was proven effective to directionally fix the SO_(2) released to turn into different solid sulfur compounds,which were determined as Ce_(2)O_(2)S,Ce_(2)S_(3) and Ce_(2)(SO_(4))_(3)·5H_(2)O and formed through the different pathways.In addition,good regeneration of the reduced CaSO_(4)-CeO_(2) mixed OC could be reached in spite of the unavoidable interaction between the included minerals in coal and the reduced mixed OC.Overall,the combined template method-made CaSO_(4)-CeO_(2) mixed OC reported herein was not only endowed with enhanced reactivity for coal conversion,but also owned the potential to directionally fix the gaseous sulfur emission,which is quite applicable as OC for simultaneous decarbonatization and desulfurization in the real CLC process.
基金financially supported by National Key R&D Program of China(2019YFE0100100)。
文摘This work presents a simulation study of several Ca-Cu looping variants with CO(2)capture,aiming at both parameter optimization and exergy analysis of these Ca-Cu looping systems.Three kinds of Ca-Cu looping are considered:(1)carbonation-calcination/reduction-oxidation;(2)carbonation-oxidation-calcination/reduction and (3)carbona tion/oxidation-calcination/reduction.A conventional Ca looping is also simulated for comparison.The influences of the calcination temperature on the mole fractions of CO(2)and CaO at the calciner outlet,the CaCO3 flow rate on the carbonator performance and the Cu/Ca ratio on the calciner performance are analyzed.The second kind of Ca-Cu looping has the highest carbonation conversion.At 1×10^5 Pa and 820℃,complete decomposition of CaCO3 can be achieved in three Ca-Cu looping systems,while the operation condition of 1×10^5 Pa,840℃is required for the conventional Ca looping system.Furthermore,the Cu/Ca molar ratio of 5.13-5.19 is required for the Ca-Cu looping.Exergy analyses show that the maximum exergy destruction occurs in the calciner for the four modes and the second Ca-Cu looping system(i.e.,carbonation-oxidation-calcination/reduction)performs the highest exergy efficiency,up to 65.04%,which is about 30%higher than that of the conventional Ca looping.
基金This work was supported by the National Natural Science Foundation of China[30871049]The sponsor had no role in the design,data collection,data analysis,data interpretation,or writing of this report.
文摘Objectives:Reported prediction rules for postoperative atrial fibrillation(AF)have suffered from inconsistent results and controversy surrounding the predictive value of a preoperative P-wave duration(PreOPWD).This study examined PreOPWD as a predictor for AF after coronary artery bypass grafting(CABG).Methods:Two-hundred-and-ninety-nine patients with sinus rhythm before off-pump CABG were recruited into the study.Patients'demographic and clinical data were evaluated prospectively.Patients were continuously monitored for the first seven postoperative days.Multiple logistic regressionwas used to determine significant predictors of AF.Findings were then combined with similar studies and a metaanalysis was performed.Results:Postoperative AF was observed in 33.1%of 299 patients.Patients with AF were older,had a prolonged PreOPWD,higher incidences of hypertension,aortic regurgitation,and mitral regurgitation.A cut-off point of PreOPWD105ms achieved a specificity of 74%,and a sensitivity of 65%for predictive of AF.Multivariate analysis showed that PreOPWD105ms(odds ratio[OR]4.63,95%confidence intervals[CI]2.66 to 8.03,P<0.001),age60 years(OR 2.72,95%CI 1.51 to 4.90,P<0.01)and hypertension(OR 2.10,95%CI 1.08 to 4.07,P<0.05)independently predicted postoperative AF.A meta-analysis of this data combined with those of ten other studies showed that PreOPWD was greater in patients with POAF,with a weighted mean difference of 3.95 ms(95%CI 1.97 to 5.92,P<0.001).Conclusion:This study confirmed,among other predictive characteristics,that PreOPWD is a powerful independent predictor of POAF.
文摘Under the condition of simulated formation temperature and pressure, the compression and shear wave velocity of the tuffaceous conglomerates and rock-fragment sandstones of the reservoirs in K1t, k1n group of Cretaceous system in Tanan are measured. The effects of lithology, mineral content, density, porosity, shale content, and water saturation on the acoustic velocity of the athrogenic rock are studied. Within the limits of our observation, some rules are found: (1) the velocity of the fine tuffaceous conglomerates is remarkably greater than that of the tuffaceous rock-fragment sandstones with good physical property;(2) the compression velocity increases with fragment content, and decreases with quartz and feldspar content in the mud;(3) the compression velocity increases with density, especially, in tuffaceous rock-fragment sandstones, the velocity keeps a good relation with density in form of power function;(4) compression and shear wave velocity decreases with porosity and shale content, velocity of the tuffaceous rock-fragment sandstones keeps a good relation with porosity and shale content in form of negative linear function, but effects of shale content is only 1/5 to 1/10 of that of the porosity, hence can be neglected;(5) with porosity increases, compression wave velocity is relatively sensitive to fluid alternation, and the rang in which velocity varies keeps positive correlation with porosity. The result provides a foundation for the research of seismic and logging data evaluation approaches in athrogenic rock reservoirs, Haita basin.
文摘In this study, polymorphisms of the DGAT1 andSTAT5A genes were detected in 528 individuals from Xinong Saanen and Guanzhong goat breeds by PCR-RFLP, PCR-SSCP and DNA sequencing methods. Three allelic variants were identified: DQ380250: g.407_408insC, AJ237937: g.6798C>T and g.6852C>T in both breeds. At g.407_408insC locus, the frequencies of C1 allele were 0.79–0.85, and frequencies of C2 allele were 0.21–0.15. At g.6852C>T locus, frequencies of C3 allele were 0.70–0.72, and frequencies of T3 allele were 0.30–0.28. Compared with goats with C1C1 and C3C3, those with C1C2 and C3T3 genotypes had significant effects on milk yield and fat percentage (P<0.05), respectively. The result showed that does with C1C1C3T3 and C1C2C3T3 had higher milk yield than those with C1C2C3C3 (P < 0.05). In addition, the combined effect of C1C2C3C3 on milk fat percentage was the highest in comparison with other combination genotypes (P<0.05).
文摘The mechanism and characteristics of spectral polarization imaging technique are presented. The present research and developing trend of spectral polarization remote sensing are introduced. A novel method of spectral polarization imaging technique is discussed, which is based on static intensity modulation adding with double refraction crystal spectrometer. The static intensity modulation consists of two retarders and one polarizer. The double refraction crystal is used to generate interference image. The spectral and four Stokes vectors information can be obtained only by one measurement. The method of static intensity modulation is deduced in detail and is simulated by computer. The spectropolarimeter experimental system is also established in the laboratory. The basic concept of the technique is verified.
基金the Science and Technology Programs of Gansu Province(Grant Nos.21JR1RA248,23YFGA0050)the Young Scholars Science Foundation of Lanzhou Jiaotong University(Grant Nos.2020039,2020017)+2 种基金the Special Funds for Guiding Local Scientific and Technological Development by the Central Government(Grant No.22ZY1QA005)the National Natural Science Foundation of China(Grant No.72361019)the Gansu Provincial Outstanding Graduate Students Innovation Star Program(Grant No.2023CXZX-574).
文摘Given the difficulty in accurately evaluating the fatigue performance of large composite wind turbine blades(referred to as blades),this paper takes the main beam structure of the blade with a rectangular cross-sectionas the simulation object and establishes a composite laminate rectangular beam structure that simultaneouslyincludes the flange,web,and adhesive layer,referred to as the blade main beam sub-structure specimen,throughthe definition of blade sub-structures.This paper examines the progressive damage evolution law of the compositelaminate rectangular beam utilizing an improved 3D Hashin failure criterion,cohesive zone model,B-K failurecriterion,and computer simulation technology.Under static loading,the layup angle of the anti-shear web hasa close relationship with the static load-carrying capacity of the composite laminate rectangular beam;under fatigueloading,the fatigue damage will first occur in the lower flange adhesive area of the whole composite laminaterectangular beam and ultimately result in the fracture failure of the entire structure.These results provide a theoreticalreference and foundation for evaluating and predicting the fatigue performance of the blade main beamstructure and even the full-size blade.
基金supported by the National Natural Science Foundation of China(51276077 and 51390494)the National Key Basic Research and Development Program(2010CB227004)
文摘In gas-solid flows, particle-particle interaction (typical, particle collision) is highly significant, despite the small particles fractional volume. Widely distributed polydisperse particle population is a typical characteristic during dynamic evolution of particles (e.g., agglomeration and fragmentation) in spite of their initial monodisperse particle distribution. The conventional direct simulation Monte Carlo (DSMC) method for particle collision tracks equally weighted simulation particles, which results in high statistical noise for particle fields if there are insufficient simulation particles in less-populated regions. In this study, a new differentially weighted DSMC (DW-DSMC) method for collisions of particles with different number weight is proposed within the framework of the general Eulerian-Lagrangian models for hydrodynamics. Three schemes (mass, momentum and energy conservation) were developed to restore the numbers of simulation particle while keeping total mass, momentum or energy of the whole system unchanged respectively. A limiting case of high-inertia particle flow was numerically simulated to validate the DW-DSMC method in terms of computational precision and efficiency. The momentum conservation scheme which leads to little fluctuation around the mass and energy of the whole system performed best. Improved resolution in particle fields and dynamic behavior could be attained simultaneously using DW-DSMC, compared with the equally weighted DSMC. Meanwhile, computational cost can be largely reduced in contrast with direct numerical simulation.
基金supported by the National Natural Science Foundation of China(No.51276210,50906030,50936001)the financial grant of North China University of Water Conservancy and Electric Power(No.201012)the National Basic Research Program(973)of China(No.2011CB707301)
文摘Chemical looping combustion (CLC) of coal has gained increasing attention as a novel combustion technology for its advantages in CO2 capture. Sulfur evolution from coal causes great harm from either the CLC operational or environmental perspective. In this research, a combined MnFe2O4 oxygen carrier (OC) was synthesized and its reaction with a typical Chinese high sulfur coal, Liuzhi (LZ) bituminous coal, was performed in a thermogravimetric analyzer (TGA)-Fourier transform infrared (FT-IR) spectrometer. Evolution of sulfur species during reaction of LZ coal with MnFeaO40C was systematically investigated through experimental means combined with thermodynamic simulation. TGA-FTIR analysis of the LZ reaction with MnFe2O4 indicated MnFe2O4 exhibited the desired superior reactivity compared to the single reference oxides Mn304 or Fe203, and SO2 produced was mainly related to oxidization of H2S by MnFe2O4. Experimental analysis of the LZ coal reaction with MnFe2O4, including X-ray diffraction and X-ray photoelectron spectroscopy analysis, verified that the main reduced counterparts of MnFe2O4 were Fe304 and MnO, in good agreement with the related thermodynamic simulation. The obtained MnO was beneficial to stabilize the reduced MnFe2O4 and avoid serious sintering, although the oxygen in MnO was not fully utilized. Meanwhile, most sulfur present in LZ coal was converted to solid MnS during LZ reaction with MnFe2O4, which was further oxidized to MnSO4. Finally, the formation of both MnS and such manganese silicates as Mn2SiO4 and MnSiO3 should be addressed to ensure the full regeneration of the reduced MnFe2O4.
基金financially supported by the National Natural Science Foundation of China (Nos.52122302,51991c351,and 51790504)the Fundamental Research Funds for the Central Universities+1 种基金the Young Elite Scientists Sponsorship Program by CASTFinancial support by the 111 Project (B20001)。
文摘Recently,two-dimensional MXene materials have attracted numerous attention in electromagnetic wave shielding/absorption.Hybridizing magnetic materials and constructing multi-dimensional structures in MXene is highly beneficial to improve electromagnetic wave absorption properties.Herein,we demonstrate a strategy for in situ growing 0 D CoNi nanoalloy-encapsulated 1 D N-doped carbon nanotubes on a2 D Ti_(3)C_(2)T_(x)MXene sheet through an electrostatic assembly process followed by a high-temperature pyrolysis process.The resultant 201-structured MXene-CoNi@N-doped carbon nanotube(MXene-CoNi@NCNT)composites displayed high surface areas(55.6-103.7 m^(2)/g),moderate magnetism(19.8-24.6 emu/g),and excellent thermal oxidation stabilities(≥ 307℃).In addition,the unique 2 D/0 D/1 D architectures entrusted the composites with abundant interfaces,various defects,and numerous nitrogen dopants.Taking advantage of the special 201 structure and the existence of both magnetic and dielectric loss,the MXeneCoNi@NCNT composite showed great impedance matching and strong attenuation performance.A strong reflection loss of-55.3 dB was achieved when the coating thickness was 2.1 mm,and a wide effective absorption bandwidth of 4.3 GHz was achieved at a thickness of 1.5 mm,much superior to that of similar absorbers.This work demonstrates a novel strategy for designing electromagnetic wave absorbers with magnetic and dielectric losses accompanied by multiple dimensional structures.