API 617标准中要求,离心压缩机产品(包括辅助设备)应确保其最短使用寿命为20年,不间断连续运转时间至少为5年。本文中的压缩机组高压缸转子在实际运行中发生了动力学失稳现象。通过分析,认为对于该机组的转子稳定性分析,应该考虑叶轮气...API 617标准中要求,离心压缩机产品(包括辅助设备)应确保其最短使用寿命为20年,不间断连续运转时间至少为5年。本文中的压缩机组高压缸转子在实际运行中发生了动力学失稳现象。通过分析,认为对于该机组的转子稳定性分析,应该考虑叶轮气动效应的影响,并发现考虑叶轮气动效应后的转子稳定性与实际运行情况一致,且不满足API 617的要求,为了改善该压缩机的转子稳定性,在叶轮口圈和平衡盘密封处添加阻旋栅,从分析结果看,该措施提高了转子的对数衰减率,满足API 617的要求。展开更多
Aim: The effects of granulocyte colony- stimu-lating factor (G-CSF) and stem cell factor (SCF) on the proliferation and osteogenic differentia-tion capacity of bone marrow mesenchymal stem cells (MSCs) were studied in...Aim: The effects of granulocyte colony- stimu-lating factor (G-CSF) and stem cell factor (SCF) on the proliferation and osteogenic differentia-tion capacity of bone marrow mesenchymal stem cells (MSCs) were studied in the experi-ment. Methods: Bone marrow MSCs were col-lected from rabbits successfully, and treated with various concentrations of G-CSF, SCF or a combination of the two. Flow cytometric ana-lyse, MTT test, CFU-F assay, and alkaline phosphatase (ALP) activity measurement were employed. Results: The results of flow cytome-try showed that immunophenotype of the cells were CD29+/CD45-, CD105+/ CD34–, CD90+/ HLADR–. MSCs were shown to constitutively express low levels of c-kit which could be en-hanced by SCF. G-CSF and SCF had an obvious facilitative effect on the proliferation of MSCs in a dose-dependent fashion. In addition, G-CSF and SCF would be effective in reversibly pre-venting their differentiation, as showed by the decrease of ALP activity, leading to self-renewal rather than differentiative cell divisions. The effects of G-CSF were superior to SCF. And cells in the group treated with combination of G-CSF and SCF showed more powerful effects than the groups treated with G-CS, SCF, or none of the two. Conclusion: On the whole, these studies demonstrated that MSCs responsed to G-CSF, SCF, and to G-CSF plus SCF in a manner that suppressed differentiation, and promotes proliferation and self-renewal, and support the view that these factors could act synergistically.展开更多
The first order deconfinement phase transitions in rotating hybrid stars are studied and it is found that if the surface tension is sufficiently large, the transition from metastable hadron matter to stable mixed hadr...The first order deconfinement phase transitions in rotating hybrid stars are studied and it is found that if the surface tension is sufficiently large, the transition from metastable hadron matter to stable mixed hadron-quark matter during the spindown history of a hybrid star can cause a glitch.展开更多
Using a realistic equation of state （EOS） of strange quark matter, namely, the modified bag model, and considering the constraints on the parameters of EOS by the observational mass limit of neutron stars, we invest...Using a realistic equation of state （EOS） of strange quark matter, namely, the modified bag model, and considering the constraints on the parameters of EOS by the observational mass limit of neutron stars, we investigate the r-mode instability window of strange stars, and find the same result as in the brief study of Haskell, Degenaar and Ho in 2012 that these instability windows are not consistent with the spin frequency and temperature observations of neutron stars in low mass X-ray binaries.展开更多
Objective：To review the recent developments in the mechanisms of epithelium sodium channels （ENaCs） induced bone formation and regulation.Data Sources：Studies written in English or Chinese were searched using Medl...Objective：To review the recent developments in the mechanisms of epithelium sodium channels （ENaCs） induced bone formation and regulation.Data Sources：Studies written in English or Chinese were searched using Medline,PubMed and the index of Chinese-language literature with time restriction from 2005 to 2014.Keywords included ENaC,bone,bone formation,osteonecrosis,estrogen,and osteoporosis.Data from published articles about the structure of ENaC,mechanism of ENaC in bone formation in recent domestic and foreign literature were selected.Study Selection：Abstract and full text of all studies were required to obtain.Studies those were not accessible and those did not focus on the keywords were excluded.Results：ENaCs are tripolymer ion channels which are assembled from homologous α,β,and γ subunits.Crystal structure of ENaCs suggests that ENaC has a central ion-channel located in the central symmetry axis of the three subunits.ENaCs are protease sensitive channels whose iron-channel activity is regulated by the proteolytic reaction.Channel opening probability of ENaCs is regulated by proteinases,mechanical force,and shear stress.Several molecules are involved in regulation of ENaCs in bone formation,including nitride oxide synthases,voltage-sensitive calcium channels,and cyclooxygenase-2.Conclusion：The pathway of ENaC involved in shear stress has an effect on stimulating osteoblasts even bone formation by estrogen interference.展开更多
The double-activated porous carbons（DAPCs）with unique bimodal pore structure were prepared by activating commercial microporous carbon（CMCs） twice through KOH（double activation） at high temperature. The as-prepa...The double-activated porous carbons（DAPCs）with unique bimodal pore structure were prepared by activating commercial microporous carbon（CMCs） twice through KOH（double activation） at high temperature. The as-prepared DAPCs show larger surface area（833 m^2·g^-1）,and the pores are composed of micropores（size of-1.8 nm） and mesopores（size of -4.5 nm）. Such special hierarchical porous structures integrate the dual advantages of micropore and mesopore, having not only the high energy storage of the micropores but also the high-rate performance of the mesopores for supercapacitors（SCs）.As a result, the optimized DAPCs-3-1 exhibits a high specific capacitance of 277 F·g^-1 at 1 A·g^-1, enhanced rate performance of 197 F·g^-1 at a high current density of 10 A·g^-1, and excellent cycling stability with 94.2% capacity retention after 10,000 cycles in the 1 mol·L^-1 Na2SO4 electrolyte. The facile double activation could be a promising method to prepare suitable porous carbons with exceptional electrochemical properties for SCs.展开更多
The main purpose of this study is to interpret the possibilities of hybrid star configurations under different phase transition paths and provide a general description of the conditions and features of the different c...The main purpose of this study is to interpret the possibilities of hybrid star configurations under different phase transition paths and provide a general description of the conditions and features of the different configurations.We assume that there are two possible phase transition paths,i.e.,from a nuclear phase to a 2flavor(2f)/3flavor(3f)quark phase directly,or first from a nuclear phase to a 2f quark phase,and then from that phase to a 3f quark phase sequentially.In addition,we consider Maxwell and Gibbs constructions based on the assumption of a first-order transition,which yields multiple configurations of hybrid stars:N-2f,N-3f,and N-2f-3f for a Maxwell construction,and N-2fmix-2f,N-3fmix-3f,N-2f3fmix,and N-2fmix-3f for a Gibbs construction.From the radii analysis of different hybrid star configurations with the same mass of 1.95M⊙,the appearance of the quark matter(from nuclear to 2f or 3f quark matter)causes a radius difference of 0.5km^2km and provides the possibility of detection by NICER in the future.However,the sequential transition from 2f to 3f quark matter is difficult to detect because the transition does not lead to too high of a change in radius(far smaller than 0.5km).The dependence solely on the measurements of the stellar radii to probe the equation of state of dense matter in neutron stars causes difficulties.Multi-messenger observations can help us to infer the interior of a neutron star in the future.展开更多
文摘Aim: The effects of granulocyte colony- stimu-lating factor (G-CSF) and stem cell factor (SCF) on the proliferation and osteogenic differentia-tion capacity of bone marrow mesenchymal stem cells (MSCs) were studied in the experi-ment. Methods: Bone marrow MSCs were col-lected from rabbits successfully, and treated with various concentrations of G-CSF, SCF or a combination of the two. Flow cytometric ana-lyse, MTT test, CFU-F assay, and alkaline phosphatase (ALP) activity measurement were employed. Results: The results of flow cytome-try showed that immunophenotype of the cells were CD29+/CD45-, CD105+/ CD34–, CD90+/ HLADR–. MSCs were shown to constitutively express low levels of c-kit which could be en-hanced by SCF. G-CSF and SCF had an obvious facilitative effect on the proliferation of MSCs in a dose-dependent fashion. In addition, G-CSF and SCF would be effective in reversibly pre-venting their differentiation, as showed by the decrease of ALP activity, leading to self-renewal rather than differentiative cell divisions. The effects of G-CSF were superior to SCF. And cells in the group treated with combination of G-CSF and SCF showed more powerful effects than the groups treated with G-CS, SCF, or none of the two. Conclusion: On the whole, these studies demonstrated that MSCs responsed to G-CSF, SCF, and to G-CSF plus SCF in a manner that suppressed differentiation, and promotes proliferation and self-renewal, and support the view that these factors could act synergistically.
基金the National Natural Science Foundation of China (Grant No. 11073008)
文摘The first order deconfinement phase transitions in rotating hybrid stars are studied and it is found that if the surface tension is sufficiently large, the transition from metastable hadron matter to stable mixed hadron-quark matter during the spindown history of a hybrid star can cause a glitch.
基金Supported by the National Natural Science Foundation of China
文摘Using a realistic equation of state （EOS） of strange quark matter, namely, the modified bag model, and considering the constraints on the parameters of EOS by the observational mass limit of neutron stars, we investigate the r-mode instability window of strange stars, and find the same result as in the brief study of Haskell, Degenaar and Ho in 2012 that these instability windows are not consistent with the spin frequency and temperature observations of neutron stars in low mass X-ray binaries.
基金a grant of the National Natural Science Foundation of China
文摘Objective：To review the recent developments in the mechanisms of epithelium sodium channels （ENaCs） induced bone formation and regulation.Data Sources：Studies written in English or Chinese were searched using Medline,PubMed and the index of Chinese-language literature with time restriction from 2005 to 2014.Keywords included ENaC,bone,bone formation,osteonecrosis,estrogen,and osteoporosis.Data from published articles about the structure of ENaC,mechanism of ENaC in bone formation in recent domestic and foreign literature were selected.Study Selection：Abstract and full text of all studies were required to obtain.Studies those were not accessible and those did not focus on the keywords were excluded.Results：ENaCs are tripolymer ion channels which are assembled from homologous α,β,and γ subunits.Crystal structure of ENaCs suggests that ENaC has a central ion-channel located in the central symmetry axis of the three subunits.ENaCs are protease sensitive channels whose iron-channel activity is regulated by the proteolytic reaction.Channel opening probability of ENaCs is regulated by proteinases,mechanical force,and shear stress.Several molecules are involved in regulation of ENaCs in bone formation,including nitride oxide synthases,voltage-sensitive calcium channels,and cyclooxygenase-2.Conclusion：The pathway of ENaC involved in shear stress has an effect on stimulating osteoblasts even bone formation by estrogen interference.
基金financially supported by the National Natural Science Foundation of China(No.51472110)Shandong Provincial Natural Science Foundation(No.ZR2016EMB05)+1 种基金University of Jinan Science Foundation(No.XKY1630)a Research Project from Ministry of Education,China(No.213021A)
文摘The double-activated porous carbons（DAPCs）with unique bimodal pore structure were prepared by activating commercial microporous carbon（CMCs） twice through KOH（double activation） at high temperature. The as-prepared DAPCs show larger surface area（833 m^2·g^-1）,and the pores are composed of micropores（size of-1.8 nm） and mesopores（size of -4.5 nm）. Such special hierarchical porous structures integrate the dual advantages of micropore and mesopore, having not only the high energy storage of the micropores but also the high-rate performance of the mesopores for supercapacitors（SCs）.As a result, the optimized DAPCs-3-1 exhibits a high specific capacitance of 277 F·g^-1 at 1 A·g^-1, enhanced rate performance of 197 F·g^-1 at a high current density of 10 A·g^-1, and excellent cycling stability with 94.2% capacity retention after 10,000 cycles in the 1 mol·L^-1 Na2SO4 electrolyte. The facile double activation could be a promising method to prepare suitable porous carbons with exceptional electrochemical properties for SCs.
基金Supported by National Natural Science Foundation of China(11903013)。
文摘The main purpose of this study is to interpret the possibilities of hybrid star configurations under different phase transition paths and provide a general description of the conditions and features of the different configurations.We assume that there are two possible phase transition paths,i.e.,from a nuclear phase to a 2flavor(2f)/3flavor(3f)quark phase directly,or first from a nuclear phase to a 2f quark phase,and then from that phase to a 3f quark phase sequentially.In addition,we consider Maxwell and Gibbs constructions based on the assumption of a first-order transition,which yields multiple configurations of hybrid stars:N-2f,N-3f,and N-2f-3f for a Maxwell construction,and N-2fmix-2f,N-3fmix-3f,N-2f3fmix,and N-2fmix-3f for a Gibbs construction.From the radii analysis of different hybrid star configurations with the same mass of 1.95M⊙,the appearance of the quark matter(from nuclear to 2f or 3f quark matter)causes a radius difference of 0.5km^2km and provides the possibility of detection by NICER in the future.However,the sequential transition from 2f to 3f quark matter is difficult to detect because the transition does not lead to too high of a change in radius(far smaller than 0.5km).The dependence solely on the measurements of the stellar radii to probe the equation of state of dense matter in neutron stars causes difficulties.Multi-messenger observations can help us to infer the interior of a neutron star in the future.
