自改革开放以来,中国经济经历了快速增长,已经成为亚洲第一、世界第二的综合经济体。然而,在世界经济下行、国际形势多变、国内改革经历阵痛的多重背景下,中国宏观经济数据通常呈现出结构突变特征,且不同部门的宏观经济变量具有较强的...自改革开放以来,中国经济经历了快速增长,已经成为亚洲第一、世界第二的综合经济体。然而,在世界经济下行、国际形势多变、国内改革经历阵痛的多重背景下,中国宏观经济数据通常呈现出结构突变特征,且不同部门的宏观经济变量具有较强的联动特征。了解中国宏观经济中的结构突变现象,对于政府部门更好地认知世界经济的运行风险和不确定性,完善宏观经济调控体系,推动宏观经济总体稳定、高质量发展具有重要作用。鉴于此,本文利用含有多个未知结构突变的因子模型对中国23个宏观经济时间序列进行建模,并进一步借鉴Ma and Tu(2023a)中的估计方法对宏观经济数据中的结构突变现象进行分析。结果表明,中国宏观经济数据在1990—2022年一共经历了6次结构突变,其发生的时间点与重大的历史事件紧密相关,例如邓小平南方谈话和党的十四大召开、2003年“非典”疫情、2020年新冠疫情等。此外,与目前研究中国宏观经济结构突变的文献相比,本文得益于因子模型的构造和精准的变点估计方法,能够识别出宏观经济系统中更多的结构变点,更好地刻画中国宏观经济的动态发展。展开更多
目的研究中药组方联合熊去氧胆酸治疗妊娠期肝内胆汁淤积症(intrahepatic cholestasis of pregnancy,ICP)的临床效果。方法选取2016年2月—2018年2月期间邢台医学高等专科学校第二附属医院100例ICP患者作为研究对象,采用随机数字表法将...目的研究中药组方联合熊去氧胆酸治疗妊娠期肝内胆汁淤积症(intrahepatic cholestasis of pregnancy,ICP)的临床效果。方法选取2016年2月—2018年2月期间邢台医学高等专科学校第二附属医院100例ICP患者作为研究对象,采用随机数字表法将100例患者分为治疗组和对照组,每组50例。两组均行熊去氧胆酸治疗,治疗组联合应用清热利湿联合疏肝利胆方,两组均治疗两周。观察比较两组治疗前后临床症状积分,记录两组患者血清甘胆酸(cholyglycine,CG)、总胆汁酸(total bile acid,TBA)及谷丙转氨酶(alanine aminotrans-ferase,ALT)水平,比较两组患者妊娠结局。结果治疗后两组ICP患者瘙痒、失眠及疲劳评分均较治疗前显著降低(P<0.05),且治疗组瘙痒、失眠及疲劳评分均显著低于对照组,两组比较差异有统计学意义(P<0.05)。治疗后两组ICP患者血清CG、TBA及ALT水平较治疗前均显著降低(P<0.05),且治疗组CG、TBA及ALT水平均低于对照组,两组比较差异有统计学意义(P<0.05)。两组患者分娩方式比较,差异无统计学意义(P>0.05),治疗组早产儿和产后出血发生率显著低于对照组,差异均有统计学意义(P<0.05)。结论中药组方联合熊去氧胆酸用于ICP患者治疗,能显著缓解患者临床症状,改善妊娠结局。展开更多
In this paper,we present a complete list of connected arc-transitive graphs of square-free order with valency 11.The list includes the complete bipartite graph K11,11,the normal Cayley graphs of dihedral groups and th...In this paper,we present a complete list of connected arc-transitive graphs of square-free order with valency 11.The list includes the complete bipartite graph K11,11,the normal Cayley graphs of dihedral groups and the graphs associated with the simple group J1 and PSL(2,p),where p is a prime.展开更多
In this paper, we introduce the definition of generalized Day-James space on Rn （n 〉 2） and give a characterization of it, which extend some known results. In addition, we provide a sufficient and necessary conditi...In this paper, we introduce the definition of generalized Day-James space on Rn （n 〉 2） and give a characterization of it, which extend some known results. In addition, we provide a sufficient and necessary condition for Day-James space, which reappeared Day＇s construction for any two-dimensional normed space to make Birkhoff orthogonality symmetry.展开更多
A Cayley graph Г=Cay(G,S)is said to be normal if G is normal in Aut Г.In this paper,we investigate the normality problem of the connected 11-valent symmetric Cayley graphs Г of finite nonabelian simple groups G,whe...A Cayley graph Г=Cay(G,S)is said to be normal if G is normal in Aut Г.In this paper,we investigate the normality problem of the connected 11-valent symmetric Cayley graphs Г of finite nonabelian simple groups G,where the vertex stabilizer A_(u) is soluble for A=Aut Г and v∈∨Г.We prove that either Г is normal or G=A_(5),A_(10),A_(54),A_(274),A_(549) or A_(1099).Further,11-valent symmetric nonnormal Cayley graphs of As,A54 and A274 are constructed.This provides some more examples of nonnormal 11-valent symmetric Cayley graphs of finite nonabelian simple groups after the first graph of this kind(of valency 11)was constructed by Fang,Ma and Wang in 2011.展开更多
During cementing operations involving cement slurry contamination,problems often occur due to the inaccurate calculation of the space fluid volume.This study,based on the turbulent dispersion theory,developed a minimu...During cementing operations involving cement slurry contamination,problems often occur due to the inaccurate calculation of the space fluid volume.This study,based on the turbulent dispersion theory,developed a minimum volume calculation model of spacer fluid to prevent cement slurry contamination.This model was used to analyze influence factors and practical calculations.The results indicated that the minimum volume of spacer fluid increase with the eccentricity of casing and injection rate and decrease with the density of cement slurry.Additionally,the better rheological properties of the cement slurry and spacer fluid would increase the volume of the spacer fluid.Furthermore,this model fitted actual field data better than other heat calculation models.展开更多
文摘自改革开放以来,中国经济经历了快速增长,已经成为亚洲第一、世界第二的综合经济体。然而,在世界经济下行、国际形势多变、国内改革经历阵痛的多重背景下,中国宏观经济数据通常呈现出结构突变特征,且不同部门的宏观经济变量具有较强的联动特征。了解中国宏观经济中的结构突变现象,对于政府部门更好地认知世界经济的运行风险和不确定性,完善宏观经济调控体系,推动宏观经济总体稳定、高质量发展具有重要作用。鉴于此,本文利用含有多个未知结构突变的因子模型对中国23个宏观经济时间序列进行建模,并进一步借鉴Ma and Tu(2023a)中的估计方法对宏观经济数据中的结构突变现象进行分析。结果表明,中国宏观经济数据在1990—2022年一共经历了6次结构突变,其发生的时间点与重大的历史事件紧密相关,例如邓小平南方谈话和党的十四大召开、2003年“非典”疫情、2020年新冠疫情等。此外,与目前研究中国宏观经济结构突变的文献相比,本文得益于因子模型的构造和精准的变点估计方法,能够识别出宏观经济系统中更多的结构变点,更好地刻画中国宏观经济的动态发展。
文摘目的研究中药组方联合熊去氧胆酸治疗妊娠期肝内胆汁淤积症(intrahepatic cholestasis of pregnancy,ICP)的临床效果。方法选取2016年2月—2018年2月期间邢台医学高等专科学校第二附属医院100例ICP患者作为研究对象,采用随机数字表法将100例患者分为治疗组和对照组,每组50例。两组均行熊去氧胆酸治疗,治疗组联合应用清热利湿联合疏肝利胆方,两组均治疗两周。观察比较两组治疗前后临床症状积分,记录两组患者血清甘胆酸(cholyglycine,CG)、总胆汁酸(total bile acid,TBA)及谷丙转氨酶(alanine aminotrans-ferase,ALT)水平,比较两组患者妊娠结局。结果治疗后两组ICP患者瘙痒、失眠及疲劳评分均较治疗前显著降低(P<0.05),且治疗组瘙痒、失眠及疲劳评分均显著低于对照组,两组比较差异有统计学意义(P<0.05)。治疗后两组ICP患者血清CG、TBA及ALT水平较治疗前均显著降低(P<0.05),且治疗组CG、TBA及ALT水平均低于对照组,两组比较差异有统计学意义(P<0.05)。两组患者分娩方式比较,差异无统计学意义(P>0.05),治疗组早产儿和产后出血发生率显著低于对照组,差异均有统计学意义(P<0.05)。结论中药组方联合熊去氧胆酸用于ICP患者治疗,能显著缓解患者临床症状,改善妊娠结局。
基金supported by the National Natural Science Foundation of China(11731002,11701503,11971248,12061089)and the Fundamental Research Funds for the Central Universities.
文摘In this paper,we present a complete list of connected arc-transitive graphs of square-free order with valency 11.The list includes the complete bipartite graph K11,11,the normal Cayley graphs of dihedral groups and the graphs associated with the simple group J1 and PSL(2,p),where p is a prime.
基金Supported by National Natural Science Foundation of China(Grant Nos.61403290,61373174 and 11401451)
文摘In this paper, we introduce the definition of generalized Day-James space on Rn （n 〉 2） and give a characterization of it, which extend some known results. In addition, we provide a sufficient and necessary condition for Day-James space, which reappeared Day＇s construction for any two-dimensional normed space to make Birkhoff orthogonality symmetry.
基金supported by the National Natural Science Foundation of China(11701503,11861076,12061089,11761079)Yunnan Applied Basic Research Projects(2018FB003,2019FB139)the third author was supported by the National Natural Science Foundation of China(11601263,11701321).
文摘A Cayley graph Г=Cay(G,S)is said to be normal if G is normal in Aut Г.In this paper,we investigate the normality problem of the connected 11-valent symmetric Cayley graphs Г of finite nonabelian simple groups G,where the vertex stabilizer A_(u) is soluble for A=Aut Г and v∈∨Г.We prove that either Г is normal or G=A_(5),A_(10),A_(54),A_(274),A_(549) or A_(1099).Further,11-valent symmetric nonnormal Cayley graphs of As,A54 and A274 are constructed.This provides some more examples of nonnormal 11-valent symmetric Cayley graphs of finite nonabelian simple groups after the first graph of this kind(of valency 11)was constructed by Fang,Ma and Wang in 2011.
基金The financial support of“Study on tight clastic rock completion and reservoir reconstruction technology in Sichuan Basin”(2016ZX05002-004-006)is greatly acknowledged.
文摘During cementing operations involving cement slurry contamination,problems often occur due to the inaccurate calculation of the space fluid volume.This study,based on the turbulent dispersion theory,developed a minimum volume calculation model of spacer fluid to prevent cement slurry contamination.This model was used to analyze influence factors and practical calculations.The results indicated that the minimum volume of spacer fluid increase with the eccentricity of casing and injection rate and decrease with the density of cement slurry.Additionally,the better rheological properties of the cement slurry and spacer fluid would increase the volume of the spacer fluid.Furthermore,this model fitted actual field data better than other heat calculation models.
