目的研究长春市35~79岁汉族人群维生素D受体基因BsmⅠ、FokⅠ位点多态性的分布特征及其与腰椎骨密度(bone mineral density,BMD)的相关性,分析不同基因型对骨代谢的调节与影响,同时研究血清TGF-β、TRACP水平与腰椎BMD的相关性,为骨质...目的研究长春市35~79岁汉族人群维生素D受体基因BsmⅠ、FokⅠ位点多态性的分布特征及其与腰椎骨密度(bone mineral density,BMD)的相关性,分析不同基因型对骨代谢的调节与影响,同时研究血清TGF-β、TRACP水平与腰椎BMD的相关性,为骨质疏松预防、早期诊断和治疗提供分子生物学依据。方法应用Hologic Discovery WA型骨密度仪检测腰椎正位(L1-L4)BMD;采用聚合酶链反应-限制性片段长度多态性(PCR-RFLP)分析BsmⅠ和FokⅠ位点多态性;采用酶联免疫吸附分析法检测血清TGF-β、TRACP水平;采用SPSS 23.0软件进行统计分析。结果在500名汉族人群中,BsmⅠ位点基因型以bb型为主,占80.2%,Bb型占15.2%,BB型占4.6%;FokⅠ位点ff基因型占18.6%,Ff型占45.8%,FF型占35.6%。BsmⅠ位点各基因型骨质疏松组与非骨质疏松组分布特征组间差异无统计学意义(P>0.05);FokⅠ位点ff基因型骨质疏松组所占比例高于非骨质疏松组,差异有统计学意义(P<0.05)。BsmⅠ位点bb基因型男性、女性BMD值均低于Bb型和BB型,但差异无统计学意义(P>0.05);FokⅠ位点ff基因型男性、女性BMD值均低于Ff型和FF型,差异有统计学意义(P<0.05)。血清TGF-β水平骨质疏松组显著低于非骨质疏松组,而TRACP水平骨质疏松组高于非骨质疏松组,组间差异有统计学意义(P<0.05)。结论本研究500名汉族人群中,BsmⅠ位点以bb基因型为主,占80.2%,各基因型骨密度值组间差异无统计学意义;FokⅠ位点ff型BMD值低于Ff型和FF型,骨质疏松组ff基因型所占比例高于非骨质疏松组,差异有统计学意义,提示ff基因型可能是骨质疏松发生的危险因素;骨质疏松组血清TGF-β水平显著低于非骨质疏松组,而TRACP水平高于非骨质疏松组,差异有统计学意义,表明TGF-β、TRACP是评价骨代谢状态的良好指标。展开更多
In the structure of double-nut ball-screw mechanism(BSM),the contact angle of the ball-screw determines the relative positional relationship between the balls and the screw as well as the nut.The contact angle is rela...In the structure of double-nut ball-screw mechanism(BSM),the contact angle of the ball-screw determines the relative positional relationship between the balls and the screw as well as the nut.The contact angle is related to geometrical parameters of the ball,the screw and the nut,which are also affected by the running status and the preload of the BSM.Considering the effect of the gy-roscopic moment on the ball in the raceway,the dynamic model of the ball in space is established under different speeds and different preloads of the BSM.By simulation of the dynamic model of the ball in space,the changing regularity of the contact angle,the helix angle,the drag torque and the mechanical efficiency of the BSM can be obtained under different speeds and different preloads.The results show that there is a nonlinear gradient relationship between contact angle,helix angle,the drag torque,the mechanical efficiency and the speeds of the ball-screw under different preloads.The contact angle is the key factor to affect the drag torque of the BSM.Through the analysis,it is found that establishing the ball dynamic model in space can better study the precision degradation law of the ball screw.展开更多
This paper presents an efficient numerical technique for solving multi-term linear systems of fractional ordinary differential equations(FODEs)which have been widely used in modeling various phenomena in engineering a...This paper presents an efficient numerical technique for solving multi-term linear systems of fractional ordinary differential equations(FODEs)which have been widely used in modeling various phenomena in engineering and science.An approximate solution of the system is sought in the formof the finite series over the Müntz polynomials.By using the collocation procedure in the time interval,one gets the linear algebraic system for the coefficient of the expansion which can be easily solved numerically by a standard procedure.This technique also serves as the basis for solving the time-fractional partial differential equations(PDEs).The modified radial basis functions are used for spatial approximation of the solution.The collocation in the solution domain transforms the equation into a system of fractional ordinary differential equations similar to the one mentioned above.Several examples have verified the performance of the proposed novel technique with high accuracy and efficiency.展开更多
This study demonstrates that beyond standard model (BSM) cosmic fundamental interactions—weak, strong, and electromagnetic forces—can be unified through a common basis of representation. This unification allows for ...This study demonstrates that beyond standard model (BSM) cosmic fundamental interactions—weak, strong, and electromagnetic forces—can be unified through a common basis of representation. This unification allows for the derivation of the fine structure constant with running points of α(t) ≈ 1/(136.9038) at high energy scales, based on electroweak interactions. Through the application of the Ising model, the running point of the elementary charge e at high energy scales is determined, and Coulomb’s law is actually derived from the Yukawa potential. Theoretically, based on S. Weinberg’s electroweak interaction theory, this study unifies the strong and electromagnetic forces by representing them with rYuka, and further advances the reconstruction of the SU(3)C×SU(1)L×U(1)EMframework on the basis of electroweak interaction concepts. In fact, the cosmic fundamental forces can interchange at the mass gap, defined as the Yukawa turning phase at rYuka ≃1.9404 fm, with the SU(3)Diag structural constant fijk on glueballs calculated, estimating a spectrum mass gap of ∆0 > 0.展开更多
碳交易市场是实现“双碳”目标的重要途径,丰富的碳金融衍生品有助于增加碳市场活性,可以更好地发挥发现价格和风险管理功能。本文借鉴欧洲碳排放权交易体系中的碳期货期权产品,设计了我国的以碳排放配额为标的碳期权合约,并选择BSM模...碳交易市场是实现“双碳”目标的重要途径,丰富的碳金融衍生品有助于增加碳市场活性,可以更好地发挥发现价格和风险管理功能。本文借鉴欧洲碳排放权交易体系中的碳期货期权产品,设计了我国的以碳排放配额为标的碳期权合约,并选择BSM模型作为碳期权的基础定价模型,描述碳价波动率与碳价之间的变化过程。研究发现,全国碳交易市场是非有效市场,具有反持久性特点,全国碳排放配额收益率具有明显的条件异方差特征,且波动具有显著的持续性。基于此,应加快完善碳市场建设,积极开展碳金融创新实践,加强碳交易市场国际合作。The carbon trading market is an important way to achieve the goal of “double carbon”. Rich carbon financial derivatives can help to increase the activity of the carbon market and better play the role of price discovery and risk management. Based on the carbon futures option products in the European carbon emission trading system, this paper designs a carbon option contract with carbon emission quota as the target in China, and chooses BSM model as the basic pricing model of carbon options to describe the changing process between carbon price volatility and carbon price. It is found that the national carbon trading market is inefficient and anti-persistent, and the national carbon emission quota yield has obvious conditional heteroscedasticity characteristics, and the fluctuation has obvious persistence. Based on this, we should speed up the improvement of carbon market construction, actively carry out carbon financial innovation practice, and strengthen international cooperation in carbon trading market.展开更多
基金Supported by the National Natural Science Foundation of China(No.51575014,51505020)Key Foundation Project of China Academy of Railway Sciences(No.2021YJ200).
文摘In the structure of double-nut ball-screw mechanism(BSM),the contact angle of the ball-screw determines the relative positional relationship between the balls and the screw as well as the nut.The contact angle is related to geometrical parameters of the ball,the screw and the nut,which are also affected by the running status and the preload of the BSM.Considering the effect of the gy-roscopic moment on the ball in the raceway,the dynamic model of the ball in space is established under different speeds and different preloads of the BSM.By simulation of the dynamic model of the ball in space,the changing regularity of the contact angle,the helix angle,the drag torque and the mechanical efficiency of the BSM can be obtained under different speeds and different preloads.The results show that there is a nonlinear gradient relationship between contact angle,helix angle,the drag torque,the mechanical efficiency and the speeds of the ball-screw under different preloads.The contact angle is the key factor to affect the drag torque of the BSM.Through the analysis,it is found that establishing the ball dynamic model in space can better study the precision degradation law of the ball screw.
基金funded by the National Key Research and Development Program of China(No.2021YFB2600704)the National Natural Science Foundation of China(No.52171272)the Significant Science and Technology Project of the Ministry of Water Resources of China(No.SKS-2022112).
文摘This paper presents an efficient numerical technique for solving multi-term linear systems of fractional ordinary differential equations(FODEs)which have been widely used in modeling various phenomena in engineering and science.An approximate solution of the system is sought in the formof the finite series over the Müntz polynomials.By using the collocation procedure in the time interval,one gets the linear algebraic system for the coefficient of the expansion which can be easily solved numerically by a standard procedure.This technique also serves as the basis for solving the time-fractional partial differential equations(PDEs).The modified radial basis functions are used for spatial approximation of the solution.The collocation in the solution domain transforms the equation into a system of fractional ordinary differential equations similar to the one mentioned above.Several examples have verified the performance of the proposed novel technique with high accuracy and efficiency.
文摘This study demonstrates that beyond standard model (BSM) cosmic fundamental interactions—weak, strong, and electromagnetic forces—can be unified through a common basis of representation. This unification allows for the derivation of the fine structure constant with running points of α(t) ≈ 1/(136.9038) at high energy scales, based on electroweak interactions. Through the application of the Ising model, the running point of the elementary charge e at high energy scales is determined, and Coulomb’s law is actually derived from the Yukawa potential. Theoretically, based on S. Weinberg’s electroweak interaction theory, this study unifies the strong and electromagnetic forces by representing them with rYuka, and further advances the reconstruction of the SU(3)C×SU(1)L×U(1)EMframework on the basis of electroweak interaction concepts. In fact, the cosmic fundamental forces can interchange at the mass gap, defined as the Yukawa turning phase at rYuka ≃1.9404 fm, with the SU(3)Diag structural constant fijk on glueballs calculated, estimating a spectrum mass gap of ∆0 > 0.
文摘碳交易市场是实现“双碳”目标的重要途径,丰富的碳金融衍生品有助于增加碳市场活性,可以更好地发挥发现价格和风险管理功能。本文借鉴欧洲碳排放权交易体系中的碳期货期权产品,设计了我国的以碳排放配额为标的碳期权合约,并选择BSM模型作为碳期权的基础定价模型,描述碳价波动率与碳价之间的变化过程。研究发现,全国碳交易市场是非有效市场,具有反持久性特点,全国碳排放配额收益率具有明显的条件异方差特征,且波动具有显著的持续性。基于此,应加快完善碳市场建设,积极开展碳金融创新实践,加强碳交易市场国际合作。The carbon trading market is an important way to achieve the goal of “double carbon”. Rich carbon financial derivatives can help to increase the activity of the carbon market and better play the role of price discovery and risk management. Based on the carbon futures option products in the European carbon emission trading system, this paper designs a carbon option contract with carbon emission quota as the target in China, and chooses BSM model as the basic pricing model of carbon options to describe the changing process between carbon price volatility and carbon price. It is found that the national carbon trading market is inefficient and anti-persistent, and the national carbon emission quota yield has obvious conditional heteroscedasticity characteristics, and the fluctuation has obvious persistence. Based on this, we should speed up the improvement of carbon market construction, actively carry out carbon financial innovation practice, and strengthen international cooperation in carbon trading market.
