In this paper,we study the ρ-meson electromagnetic form factors(EMFFs)within the framework of the light-front quark model.The physical form factors G_(C,M,Q)(Q^(2))of the ρ-meson,as well as the charged square radius...In this paper,we study the ρ-meson electromagnetic form factors(EMFFs)within the framework of the light-front quark model.The physical form factors G_(C,M,Q)(Q^(2))of the ρ-meson,as well as the charged square radius<r^(2)>,the magnetic moment μ,and the quadrupole moment Q,are calculated,which describe the behaviors of EMFFs at zero momentum transfer.Using the type-Ⅱ replacement,we find that the zero-mode does contribute zero to the matrix element S_(00)^(+).It is found that the“M→M_(0)”replacement improves the angular condition remarkably,which permits different prescriptions of ρ-meson EMFFs to give the consistent results.The residual tiny violation of angular condition needs other explanations beyond the zero-mode contributions.Our results indicate that the relativistic effects or interaction internal structure are weaken in the zero-binding limit.This work is also applicable to other spin-1 particles.展开更多
The effects of magnesium oxide （MgO） on the flame retardant performance of intumescent systems based on ammonium polyphosphate （APP） and pentaerythritol （PER） in ethylene vinyl acetate copolymer （EVA） were stu...The effects of magnesium oxide （MgO） on the flame retardant performance of intumescent systems based on ammonium polyphosphate （APP） and pentaerythritol （PER） in ethylene vinyl acetate copolymer （EVA） were studied. The results showed that MgO affects both the quality and quantity of residual char. There is an optimal value for the loading amount of MgO. More or less MgO loading may cause the formation of defective char layers and worsen the flame retardancy of EVA. According to the results of limiting oxygen index （LOI）, vertical flammability test （UL94 rating） and cone calorimetry （CONE）, the best flame retardancy with a strong and well intumescent char is obtained from the sample with 1 wt% of MgO, which has the highest LOI value of 27.9, UL94 rating of V-0 and the lowest peak heat release rate of 242 kW·m-2.展开更多
Amorphous Al2 O3-reinforced Al composite(am-Al2 O3/Al) compacted from ultrafine Al powders for high-temperature usages confronts with drawbacks because crystallization of am-Al2 O3 at high temperatures will result in ...Amorphous Al2 O3-reinforced Al composite(am-Al2 O3/Al) compacted from ultrafine Al powders for high-temperature usages confronts with drawbacks because crystallization of am-Al2 O3 at high temperatures will result in serious strength loss.Aiming at this unsolved problem,in this study,high-temperature Al materials with enhanced thermal stability were developed through introducing more thermally stable nano-sized particles via high-temperature pre-treatment of ultrafine A1 powders.It was found that the pre-treatment at ≤550℃ could introduce a few Al2 O3 in the Al matrix and increase the strength of the composites,but the strength was still below that of am-Al2 O3/Al because without being pinned firmly,grain boundaries(GBs) were softened at high temperature and intergranular fracture happened.When the pre-treatment was carried out at 600℃,nitridation and oxidation processes happened simultaneously,producing large numbers of intergranular(AlN+γ-Al2 O3) particles.GB sliding and intergranular fracture were suppressed;therefore,higher strength than that of am-Al2 O3/Al was realized.Furthermore,the(AIN+γ-Al2 O3)/Al exhibited more superior thermal stability compared to amAl2 O3/Al for annealing treatment at 580℃ for 8 h.Therefore,an effective way to fabricate high-temperature Al composite with enhanced thermal stability was developed in this study.展开更多
BACKGROUND Cryptococcus is a systemic opportunistic pathogenic fungus that can cause infections in both immunocompromised and immunocompetent hosts,with diverse clinical manifestations,ranging from asymptomatic pulmon...BACKGROUND Cryptococcus is a systemic opportunistic pathogenic fungus that can cause infections in both immunocompromised and immunocompetent hosts,with diverse clinical manifestations,ranging from asymptomatic pulmonary lesions to disseminated central nervous system infections.The incidence of pulmonary cryptococcosis(PC)has rapidly increased in recent years,with an increasing proportion of non-human immunodeficiency virus-infected and immunocompetent patients making its diagnosis challenging.If not properly recognized,PC can lead to systemic dissemination and high mortality rates.Early diagnosis and treatment can improve the prognosis.This study summarizes the clinical features of three immunocompetent children with PC who presented with chest pain to raise clinicians'awareness of the disease and reduce mortality.CASE SUMMARY Three male pediatric patients in good health were hospitalized because of chest pain without cough or fever.Chest computed tomography(CT)revealed pleuralbased nodules and consolidation with cavitation.A lung biopsy was performed in one case,and Cryptococcus was cultured from the pathological tissues.Cryptococcus was detected in the alveolar lavage fluid,and serum Cryptococcus capsular(C.capsular)polysaccharide antigen was positive in one case,and the other case was positive for serum C.capsular polysaccharide.All patients received oral fluconazole treatment.Follow-up chest CT scans after six months showed significant resolution of the lesions.CONCLUSION PC can also occur in immunocompetent children.When encountering children with chest pain only in the clinic,one should be vigilant about PC,promptly complete the relevant examinations,and avoid misdiagnosis.展开更多
Background To study the predictive factors of resting energy expenditure(REE)and evaluate the accuracy of predicted equations with indirect calorimeter(IC)in Chinese school-age children,particularly for the obese popu...Background To study the predictive factors of resting energy expenditure(REE)and evaluate the accuracy of predicted equations with indirect calorimeter(IC)in Chinese school-age children,particularly for the obese population.Methods Recruited children were from the department of child healthcare in Nanjing children's hospital during July 2014-September 2015.Anthropometric parameters and body composition were measured by bioelectrical impedance.Measured REE was assessed by IC.Predicted REE was estimated using ten published equations.Results 248 children aged 7-13 years were recruited,including 148 obese[body mass index standard deviation score(BMISDS)=2.48±0.91]and 100 non-obese(BMISDS=-0.96±1.08).The unit mass of REE(REE/kg)in obese group(29.06±5.74)was lower than that in non-obese group(37.51±6.56).The stepwise regression showed that age,BMISDS and fat-free mass(FFM)had a major impact on REE/kg as the regression equation:Y=54.41-1.36×X_(1)-2.25×X_(2)-0.16×X_(3)(Y REE/kg,X_(1)age,X_(2)BMISDS,X_(3)FFM;R=0.633,R^(2)=0.401,P<0.01).The accuracy of predicted REE in obese subjects was 62.16%by the new predictive equations.Conclusions The REE/kg in obese children was lower and closely correlated with age,BMISDS and FFM.It is necessary to validate the new predictive equation in a larger sample to estimate energy requirements,particularly for children with obesity.展开更多
We calculate the decay constants of light and heavy-light pseudoscalar and vector mesons with improved soft-wall holographic wavefuntions, which take into account the effects of both quark masses and dynamical spins. ...We calculate the decay constants of light and heavy-light pseudoscalar and vector mesons with improved soft-wall holographic wavefuntions, which take into account the effects of both quark masses and dynamical spins. We find that the predicted decay constants, especially for the ratio fV/fP, based on light-front holographic QCD, can be significantly improved, once the dynamical spin effects are taken into account by introducing the helicity-dependent wavefunctions. We also perform detailed χ2 analyses for the holographic parameters （i.e. the mass-scale parameter κ and the quark masses）, by confronting our predictions with the data for the charged-meson decay constants and the meson spectra. The fitted values for these parameters are generally in agreement with those obtained by fitting to the Regge trajectories. At the same time, most of our results for the decay constants and their ratios agree with the data as well as the predictions based on lattice QCD and QCD sum rule approaches, with only a few exceptions observed.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.11875122,12175025,and 12147102)Tongling University Talent Program(Grant No.R23100)。
文摘In this paper,we study the ρ-meson electromagnetic form factors(EMFFs)within the framework of the light-front quark model.The physical form factors G_(C,M,Q)(Q^(2))of the ρ-meson,as well as the charged square radius<r^(2)>,the magnetic moment μ,and the quadrupole moment Q,are calculated,which describe the behaviors of EMFFs at zero momentum transfer.Using the type-Ⅱ replacement,we find that the zero-mode does contribute zero to the matrix element S_(00)^(+).It is found that the“M→M_(0)”replacement improves the angular condition remarkably,which permits different prescriptions of ρ-meson EMFFs to give the consistent results.The residual tiny violation of angular condition needs other explanations beyond the zero-mode contributions.Our results indicate that the relativistic effects or interaction internal structure are weaken in the zero-binding limit.This work is also applicable to other spin-1 particles.
基金financially supported by the National Natural Science Foundation of China(No.51203136)the Scientific Special Fund of Zhejiang Province(No.2013C01074)
文摘The effects of magnesium oxide （MgO） on the flame retardant performance of intumescent systems based on ammonium polyphosphate （APP） and pentaerythritol （PER） in ethylene vinyl acetate copolymer （EVA） were studied. The results showed that MgO affects both the quality and quantity of residual char. There is an optimal value for the loading amount of MgO. More or less MgO loading may cause the formation of defective char layers and worsen the flame retardancy of EVA. According to the results of limiting oxygen index （LOI）, vertical flammability test （UL94 rating） and cone calorimetry （CONE）, the best flame retardancy with a strong and well intumescent char is obtained from the sample with 1 wt% of MgO, which has the highest LOI value of 27.9, UL94 rating of V-0 and the lowest peak heat release rate of 242 kW·m-2.
基金supported by the National Natural Science Foundation of China (Nos. U1508216 and 51771194)the Youth Innovation Promotion Association CAS (No. 2016179)the National Key R&D Program of China (No. 2017YFB0703104)。
文摘Amorphous Al2 O3-reinforced Al composite(am-Al2 O3/Al) compacted from ultrafine Al powders for high-temperature usages confronts with drawbacks because crystallization of am-Al2 O3 at high temperatures will result in serious strength loss.Aiming at this unsolved problem,in this study,high-temperature Al materials with enhanced thermal stability were developed through introducing more thermally stable nano-sized particles via high-temperature pre-treatment of ultrafine A1 powders.It was found that the pre-treatment at ≤550℃ could introduce a few Al2 O3 in the Al matrix and increase the strength of the composites,but the strength was still below that of am-Al2 O3/Al because without being pinned firmly,grain boundaries(GBs) were softened at high temperature and intergranular fracture happened.When the pre-treatment was carried out at 600℃,nitridation and oxidation processes happened simultaneously,producing large numbers of intergranular(AlN+γ-Al2 O3) particles.GB sliding and intergranular fracture were suppressed;therefore,higher strength than that of am-Al2 O3/Al was realized.Furthermore,the(AIN+γ-Al2 O3)/Al exhibited more superior thermal stability compared to amAl2 O3/Al for annealing treatment at 580℃ for 8 h.Therefore,an effective way to fabricate high-temperature Al composite with enhanced thermal stability was developed in this study.
基金Supported by Shenzhen Fund for Guangdong Provincial High-Level Clinical Key Specialties,No.SZGSP012Shenzhen Key Medical Discipline Construction Fund,No.SZXK032。
文摘BACKGROUND Cryptococcus is a systemic opportunistic pathogenic fungus that can cause infections in both immunocompromised and immunocompetent hosts,with diverse clinical manifestations,ranging from asymptomatic pulmonary lesions to disseminated central nervous system infections.The incidence of pulmonary cryptococcosis(PC)has rapidly increased in recent years,with an increasing proportion of non-human immunodeficiency virus-infected and immunocompetent patients making its diagnosis challenging.If not properly recognized,PC can lead to systemic dissemination and high mortality rates.Early diagnosis and treatment can improve the prognosis.This study summarizes the clinical features of three immunocompetent children with PC who presented with chest pain to raise clinicians'awareness of the disease and reduce mortality.CASE SUMMARY Three male pediatric patients in good health were hospitalized because of chest pain without cough or fever.Chest computed tomography(CT)revealed pleuralbased nodules and consolidation with cavitation.A lung biopsy was performed in one case,and Cryptococcus was cultured from the pathological tissues.Cryptococcus was detected in the alveolar lavage fluid,and serum Cryptococcus capsular(C.capsular)polysaccharide antigen was positive in one case,and the other case was positive for serum C.capsular polysaccharide.All patients received oral fluconazole treatment.Follow-up chest CT scans after six months showed significant resolution of the lesions.CONCLUSION PC can also occur in immunocompetent children.When encountering children with chest pain only in the clinic,one should be vigilant about PC,promptly complete the relevant examinations,and avoid misdiagnosis.
基金supported by grants from Jiangsu Province Research Project(BE2015607)National Natural Science Foundation(81273064)
文摘Background To study the predictive factors of resting energy expenditure(REE)and evaluate the accuracy of predicted equations with indirect calorimeter(IC)in Chinese school-age children,particularly for the obese population.Methods Recruited children were from the department of child healthcare in Nanjing children's hospital during July 2014-September 2015.Anthropometric parameters and body composition were measured by bioelectrical impedance.Measured REE was assessed by IC.Predicted REE was estimated using ten published equations.Results 248 children aged 7-13 years were recruited,including 148 obese[body mass index standard deviation score(BMISDS)=2.48±0.91]and 100 non-obese(BMISDS=-0.96±1.08).The unit mass of REE(REE/kg)in obese group(29.06±5.74)was lower than that in non-obese group(37.51±6.56).The stepwise regression showed that age,BMISDS and fat-free mass(FFM)had a major impact on REE/kg as the regression equation:Y=54.41-1.36×X_(1)-2.25×X_(2)-0.16×X_(3)(Y REE/kg,X_(1)age,X_(2)BMISDS,X_(3)FFM;R=0.633,R^(2)=0.401,P<0.01).The accuracy of predicted REE in obese subjects was 62.16%by the new predictive equations.Conclusions The REE/kg in obese children was lower and closely correlated with age,BMISDS and FFM.It is necessary to validate the new predictive equation in a larger sample to estimate energy requirements,particularly for children with obesity.
基金Supported by National Natural Science Foundation of China(11475055,11675061,11435003)Q.Chang is also supported by the Foundation for the Author of National Excellent Doctoral Dissertation of China(201317)+1 种基金the Program for Science and Technology Innovation Talents in Universities of Henan Province(14HASTIT036)the Excellent Youth Foundation of HNNU.X.L.is also supported in part by the self-determined research funds of CCNU from the colleges’basic research and operation of MOE(CCNU18TS029)
文摘We calculate the decay constants of light and heavy-light pseudoscalar and vector mesons with improved soft-wall holographic wavefuntions, which take into account the effects of both quark masses and dynamical spins. We find that the predicted decay constants, especially for the ratio fV/fP, based on light-front holographic QCD, can be significantly improved, once the dynamical spin effects are taken into account by introducing the helicity-dependent wavefunctions. We also perform detailed χ2 analyses for the holographic parameters （i.e. the mass-scale parameter κ and the quark masses）, by confronting our predictions with the data for the charged-meson decay constants and the meson spectra. The fitted values for these parameters are generally in agreement with those obtained by fitting to the Regge trajectories. At the same time, most of our results for the decay constants and their ratios agree with the data as well as the predictions based on lattice QCD and QCD sum rule approaches, with only a few exceptions observed.
