Shrinkage porosity is a type of random distribution defects and exists in most large castings. Different from the periodic symmetry defects or certain distribution defects, shrinkage porosity presents a random "c...Shrinkage porosity is a type of random distribution defects and exists in most large castings. Different from the periodic symmetry defects or certain distribution defects, shrinkage porosity presents a random "cloud-like" configuration, which brings difficulties in quantifying the effective performance of defected casting. In this paper, the influences of random shrinkage porosity on the equivalent elastic modulus of QT400-18 casting were studied by a numerical statistics approach. An improved random algorithm was applied into the lattice model to simulate the "cloud-like" morphology of shrinkage porosity. Then, a large number of numerical samples containing random levels of shrinkage were generated by the proposed algorithm. The stress concentration factor and equivalent elastic modulus of these numerical samples were calculated. Based on a statistical approach, the effects of shrinkage porosity's distribution characteristics, such as area fraction, shape, and relative location on the casting's equivalent mechanical properties were discussed respectively. It is shown that the approach with randomly distributed defects has better predictive capabilities than traditional methods. The following conclusions can be drawn from the statistical simulations:(1) the effective modulus decreases remarkably if the shrinkage porosity percent is greater than 1.5%;(2) the average Stress Concentration Factor(SCF) produced by shrinkage porosity is about 2.0;(3) the defect's length across the loading direction plays a more important role in the effective modulus than the length along the loading direction;(4) the surface defect perpendicular to loading direction reduces the mean modulus about 1.5% more than a defect of other position.展开更多
Objective To explore the personality characteristics of children with tic disorders and their relationship with family factors. Methods Sixty cases of children with tic disorders diagnosed in our hospital were selecte...Objective To explore the personality characteristics of children with tic disorders and their relationship with family factors. Methods Sixty cases of children with tic disorders diagnosed in our hospital were selected as the case group and 65 cases of normal children were selected as the control group. The children of two groups were assessed using Eysenck Personality Questionnaire(EPQ), Family Environment Scale(FES-CV) and general situation questionnaire of family(GSQ), respectively. The scores of EPQ personality characteristics, FES-CV and GSQ scores were compared for the children in the two groups. The Person correlation analysis method was used to analyze the correlation between personality scores of children in case group and family environment factors. Results The general situation questionnaire results showed that there was significant statistically difference in parenting style, parental education level and family types of the children between case group and control group(P<0.05); EPQ results showed that the neuroticism and psychoticism scores of children in the case group were significantly higher than those in the control group(P<0.05) and the lying degree scores in the control group were significantly higher than those in the case group(P<0.05); FES-CV results showed that the family cohesion scores of the case group were significantly lower than those of the control group(P<0.05), and the family conflict scores in the case group were significantly higher than those in the control group(P<0.05). The Person correlation analysis results indicated that the psychoticism score was negatively correlated with the score of family cohesion(P<0.05), and positively correlated with family conflict(P<0.05), while the neuroticism score was positively correlated with family conflict score(P<0.05). Conclusion The children with tic disorders have significant personality deviation compared to the normal children, and the personality deviation degree is correlated to family contradiction, and family cohesion.展开更多
The genus Alloxiphia Wei,2002 was redescribed based on new materials.Two species from China were described as new to science,namely A.tianmua Wei,sp.nov.and A.qinlingia Wei,sp.nov.A key to known species of the genus i...The genus Alloxiphia Wei,2002 was redescribed based on new materials.Two species from China were described as new to science,namely A.tianmua Wei,sp.nov.and A.qinlingia Wei,sp.nov.A key to known species of the genus is provided.The differences among Alloxiphia,Palpixiphia Maa,1949 and Hyperxiphia Maa,1949 were also briefly discussed.展开更多
The fall armyworm(FAW),Spodoptera frugiperda,has colonized and caused consistent damage in the Eastern hemisphere.The identification of various FAW strains is essential for developing precise prevention and control me...The fall armyworm(FAW),Spodoptera frugiperda,has colonized and caused consistent damage in the Eastern hemisphere.The identification of various FAW strains is essential for developing precise prevention and control measures.The triosephosphate isomerase(Tpi)gene is recognized as an effective marker closely linked to FAW subpopulations.However,most current studies primarily focus on the comparison of variations in specific gene sites of this gene.In this study,we conducted full-length sequencing of the Tpi genes from 5 representative FAW groups.Our findings revealed that the Tpi genes varied in length from 1220 to 1420 bp,with the primary variation occurring within 4 introns.Notably,the exon lengths remained consistent,at 747 bp,with 37 observed base variations;however,no amino acid variations were detected.Through sequence alignment,we identified 8 stable variation sites that can be used to distinguish FAW strains in the Eastern hemisphere.Additionally,we performed strain identification on 1569 FAW samples collected from 19 provinces in China between 2020 and 2021.The extensive analysis indicated the absence of the rice strain in the samples.Instead,we only detected the presence of the corn strain and the Zambia strain,with the Zambia strain being distributed in a very low proportion(3.44%).Furthermore,the corn strain could be further categorized into 2 subgroups.This comprehensive study provides a valuable reference for enhancing our understanding of FAW population differentiation and for improving monitoring and early warning efforts.展开更多
Spray experiments of RP-3 jet fuel at non-evaporating and evaporating environments were studied on a constant volume spray chamber,and diffusive back-imaging technique was used to capture the transient spray developme...Spray experiments of RP-3 jet fuel at non-evaporating and evaporating environments were studied on a constant volume spray chamber,and diffusive back-imaging technique was used to capture the transient spray development processes.Spray tip penetration,projected spray area and cone angle of RP-3 jet fuel were derived from the spray development images,and compared to those of diesel fuel.It is observed that non-evaporating sprays of RP-3 jet fuel and diesel fuel do not exhibit significant differences,as their spray penetration distances,projected spray areas and spray cone angles are consistent at most test conditions.The evaporating sprays of RP-3 jet fuel produce shorter liquid-phase penetration distances and lower projected spray areas than those of diesel fuel,and these differences are particularly pronounced at low ambient temperatures.However,fuel effects on the evaporating spray cone angle are insignificant.Further,increased ambient density or ambient temperature shortens the liquid-phase spray penetration distance and reduces the liquid-phase spray area,and these effects are more pronounced for diesel fuel than RP-3 jet fuel.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.51305350)the Basic Research Foundation of NWPU(No.3102014JCQ01045)
文摘Shrinkage porosity is a type of random distribution defects and exists in most large castings. Different from the periodic symmetry defects or certain distribution defects, shrinkage porosity presents a random "cloud-like" configuration, which brings difficulties in quantifying the effective performance of defected casting. In this paper, the influences of random shrinkage porosity on the equivalent elastic modulus of QT400-18 casting were studied by a numerical statistics approach. An improved random algorithm was applied into the lattice model to simulate the "cloud-like" morphology of shrinkage porosity. Then, a large number of numerical samples containing random levels of shrinkage were generated by the proposed algorithm. The stress concentration factor and equivalent elastic modulus of these numerical samples were calculated. Based on a statistical approach, the effects of shrinkage porosity's distribution characteristics, such as area fraction, shape, and relative location on the casting's equivalent mechanical properties were discussed respectively. It is shown that the approach with randomly distributed defects has better predictive capabilities than traditional methods. The following conclusions can be drawn from the statistical simulations:(1) the effective modulus decreases remarkably if the shrinkage porosity percent is greater than 1.5%;(2) the average Stress Concentration Factor(SCF) produced by shrinkage porosity is about 2.0;(3) the defect's length across the loading direction plays a more important role in the effective modulus than the length along the loading direction;(4) the surface defect perpendicular to loading direction reduces the mean modulus about 1.5% more than a defect of other position.
文摘Objective To explore the personality characteristics of children with tic disorders and their relationship with family factors. Methods Sixty cases of children with tic disorders diagnosed in our hospital were selected as the case group and 65 cases of normal children were selected as the control group. The children of two groups were assessed using Eysenck Personality Questionnaire(EPQ), Family Environment Scale(FES-CV) and general situation questionnaire of family(GSQ), respectively. The scores of EPQ personality characteristics, FES-CV and GSQ scores were compared for the children in the two groups. The Person correlation analysis method was used to analyze the correlation between personality scores of children in case group and family environment factors. Results The general situation questionnaire results showed that there was significant statistically difference in parenting style, parental education level and family types of the children between case group and control group(P<0.05); EPQ results showed that the neuroticism and psychoticism scores of children in the case group were significantly higher than those in the control group(P<0.05) and the lying degree scores in the control group were significantly higher than those in the case group(P<0.05); FES-CV results showed that the family cohesion scores of the case group were significantly lower than those of the control group(P<0.05), and the family conflict scores in the case group were significantly higher than those in the control group(P<0.05). The Person correlation analysis results indicated that the psychoticism score was negatively correlated with the score of family cohesion(P<0.05), and positively correlated with family conflict(P<0.05), while the neuroticism score was positively correlated with family conflict score(P<0.05). Conclusion The children with tic disorders have significant personality deviation compared to the normal children, and the personality deviation degree is correlated to family contradiction, and family cohesion.
基金partly supported by the National Natural Science Foundation of China(31970447,31672344)。
文摘The genus Alloxiphia Wei,2002 was redescribed based on new materials.Two species from China were described as new to science,namely A.tianmua Wei,sp.nov.and A.qinlingia Wei,sp.nov.A key to known species of the genus is provided.The differences among Alloxiphia,Palpixiphia Maa,1949 and Hyperxiphia Maa,1949 were also briefly discussed.
基金supported by Shenzhen Natural Science Foundation(JCYJ20200109150629266)the National Natural Science Foundation of China(32302352 and 32372546)+1 种基金Sci-Tech Innovation 2030 Agenda(2022ZD04021)Shenzhen Science and Technology Program(KQTD20180411143628272).
文摘The fall armyworm(FAW),Spodoptera frugiperda,has colonized and caused consistent damage in the Eastern hemisphere.The identification of various FAW strains is essential for developing precise prevention and control measures.The triosephosphate isomerase(Tpi)gene is recognized as an effective marker closely linked to FAW subpopulations.However,most current studies primarily focus on the comparison of variations in specific gene sites of this gene.In this study,we conducted full-length sequencing of the Tpi genes from 5 representative FAW groups.Our findings revealed that the Tpi genes varied in length from 1220 to 1420 bp,with the primary variation occurring within 4 introns.Notably,the exon lengths remained consistent,at 747 bp,with 37 observed base variations;however,no amino acid variations were detected.Through sequence alignment,we identified 8 stable variation sites that can be used to distinguish FAW strains in the Eastern hemisphere.Additionally,we performed strain identification on 1569 FAW samples collected from 19 provinces in China between 2020 and 2021.The extensive analysis indicated the absence of the rice strain in the samples.Instead,we only detected the presence of the corn strain and the Zambia strain,with the Zambia strain being distributed in a very low proportion(3.44%).Furthermore,the corn strain could be further categorized into 2 subgroups.This comprehensive study provides a valuable reference for enhancing our understanding of FAW population differentiation and for improving monitoring and early warning efforts.
基金supported by National Natural Science Foundation of China(Grant Nos.52022058 and 51776124)by Ministry of Education of China(Grant No.6141A020335)。
文摘Spray experiments of RP-3 jet fuel at non-evaporating and evaporating environments were studied on a constant volume spray chamber,and diffusive back-imaging technique was used to capture the transient spray development processes.Spray tip penetration,projected spray area and cone angle of RP-3 jet fuel were derived from the spray development images,and compared to those of diesel fuel.It is observed that non-evaporating sprays of RP-3 jet fuel and diesel fuel do not exhibit significant differences,as their spray penetration distances,projected spray areas and spray cone angles are consistent at most test conditions.The evaporating sprays of RP-3 jet fuel produce shorter liquid-phase penetration distances and lower projected spray areas than those of diesel fuel,and these differences are particularly pronounced at low ambient temperatures.However,fuel effects on the evaporating spray cone angle are insignificant.Further,increased ambient density or ambient temperature shortens the liquid-phase spray penetration distance and reduces the liquid-phase spray area,and these effects are more pronounced for diesel fuel than RP-3 jet fuel.
