非线性Ablowitz-Kaup-Newell-Segur方程是一类应用广泛的非线性偏微分方程。(2 + 1)维空时分数阶Ablowitz-Kaup-Newell-Segur方程常用于描述孤立波在光纤中传播的物理过程,本文利用复行波变换和扩展的Tanh-函数展开法,获得了(2 + 1)维...非线性Ablowitz-Kaup-Newell-Segur方程是一类应用广泛的非线性偏微分方程。(2 + 1)维空时分数阶Ablowitz-Kaup-Newell-Segur方程常用于描述孤立波在光纤中传播的物理过程,本文利用复行波变换和扩展的Tanh-函数展开法,获得了(2 + 1)维空时分数阶Ablowitz-Kaup-Newell-Segur方程的系列新的精确行波解。The Ablowitz-Kaup-Newell-Segur (AKNS) equations, a class of nonlinear partial differential equations, find their utility in a wide array of applications. The space-time fractional (2 + 1)-dimensional AKNS equation, in particular, is capable of describing the physical process of solitary wave propagation in optical fibers. A new class of exact traveling wave solutions of (2 + 1)-dimensional generalized fractional AKNS equation are obtained by employing complex traveling wave transformation and extended Tanh expansion method.展开更多
Based on the three-dimensional elastic-plastic finite element analysis of the 8"(203.2 mm)drill collar joint,this paper studies the mechanical characteristics of the pin and box of NC56 drill collar joints under ...Based on the three-dimensional elastic-plastic finite element analysis of the 8"(203.2 mm)drill collar joint,this paper studies the mechanical characteristics of the pin and box of NC56 drill collar joints under complex load conditions,as well as the downhole secondary makeup features,and calculates the downhole equivalent impact torque with the relative offset at the shoulder of internal and external threads.On the basis of verifying the correctness of the calculation results by using measured results in Well GT1,the prediction model of the downhole equivalent impact torque is formed and applied in the first extra-deep well with a depth over 10000 m in China(Well SDTK1).The results indicate that under complex loads,the stress distribution in drill collar joints is uneven,with relatively higher von Mises stress at the shoulder and the threads close to the shoulder.For 203.2 mm drill collar joints pre-tightened according to the make-up torque recommended by American Petroleum Institute standards,when the downhole equivalent impact torque exceeds 65 kN·m,the preload balance of the joint is disrupted,leading to secondary make-up of the joint.As the downhole equivalent impact torque increases,the relative offset at the shoulder of internal and external threads increases.The calculation results reveal that there exists significant downhole impact torque in Well SDTK1 with complex loading environment.It is necessary to use double shoulder collar joints to improve the impact torque resistance of the joint or optimize the operating parameters to reduce the downhole impact torque,and effectively prevent drilling tool failure.展开更多
背景:程序性细胞死亡受体1(programmed death receptor-1,PD-1)在高糖环境下影响骨髓间充质干细胞成骨分化的作用机制尚不清楚。目的:探讨高糖环境中PD-1对大鼠骨髓间充质干细胞成骨分化的影响及其调控机制。方法:将大鼠骨髓间充质干细...背景:程序性细胞死亡受体1(programmed death receptor-1,PD-1)在高糖环境下影响骨髓间充质干细胞成骨分化的作用机制尚不清楚。目的:探讨高糖环境中PD-1对大鼠骨髓间充质干细胞成骨分化的影响及其调控机制。方法:将大鼠骨髓间充质干细胞随机分为正常糖组(5.6 mmol/L)、高糖组(30 mmol/L)、PD-1过表达组、PD-1过表达空载组、PD-1敲低组、PD-1敲低空载组、PI3K/AKT通路抑制剂组(PD-1敲低+5μmol/L LY294002)。通过在高糖培养基中培养大鼠骨髓间充质干细胞来模拟体外糖尿病环境,采用qRT-PCR检测大鼠骨髓间充质干细胞中PD-1及其配体PD-L1和成骨标志物Runx2、OSX的mRNA表达,采用碱性磷酸酶染色和茜素红S染色观察成骨分化能力,采用CCK-8检测细胞增殖情况,采用Western blot检测PD-1、PD-L1、p-PI3K、p-AKT的蛋白表达。结果与结论:①高糖组PD-1及PD-L1表达显著高于正常糖组,高糖组骨髓间充质干细胞的成骨分化能力较正常糖组显著下降;②敲低PD-1表达可以促进骨髓间充质干细胞的成骨分化、增加细胞增殖活性,同时激活PI3K/AKT通路;③加入PI3K/AKT通路抑制剂LY294002后,骨髓间充质干细胞成骨分化能力显著下降。结果表明:PD-1依赖于PI3K/AKT信号通路抑制高糖环境下大鼠骨髓间充质干细胞的成骨分化。展开更多
基于Well-being理论对风储混合电力系统进行了充裕度评估。所采用的Well-being充裕度指标中考虑了N-1确定性准则,不仅能计及发电系统的充裕性,还能计及输电系统的充裕性,因此更加合理且适用于发输电系统的充裕度评估。以简单的RBTS(Roy ...基于Well-being理论对风储混合电力系统进行了充裕度评估。所采用的Well-being充裕度指标中考虑了N-1确定性准则,不仅能计及发电系统的充裕性,还能计及输电系统的充裕性,因此更加合理且适用于发输电系统的充裕度评估。以简单的RBTS(Roy Billinton test system)以及规模稍大的IEEE-RTS79为算例,仿真分析了风电及电池储能系统(battery energy storage system,BESS)并网对电力系统充裕度的影响。结果表明,与风电场的集中布置相比,分散布置更有利于系统的充裕性;BESS对含风电场的电力系统充裕度提升作用明显,在电力系统瞬时备用控制中具有重要的作用。展开更多
文摘非线性Ablowitz-Kaup-Newell-Segur方程是一类应用广泛的非线性偏微分方程。(2 + 1)维空时分数阶Ablowitz-Kaup-Newell-Segur方程常用于描述孤立波在光纤中传播的物理过程,本文利用复行波变换和扩展的Tanh-函数展开法,获得了(2 + 1)维空时分数阶Ablowitz-Kaup-Newell-Segur方程的系列新的精确行波解。The Ablowitz-Kaup-Newell-Segur (AKNS) equations, a class of nonlinear partial differential equations, find their utility in a wide array of applications. The space-time fractional (2 + 1)-dimensional AKNS equation, in particular, is capable of describing the physical process of solitary wave propagation in optical fibers. A new class of exact traveling wave solutions of (2 + 1)-dimensional generalized fractional AKNS equation are obtained by employing complex traveling wave transformation and extended Tanh expansion method.
基金Supported by the National Natural Science Foundation of China(52174003,52374008).
文摘Based on the three-dimensional elastic-plastic finite element analysis of the 8"(203.2 mm)drill collar joint,this paper studies the mechanical characteristics of the pin and box of NC56 drill collar joints under complex load conditions,as well as the downhole secondary makeup features,and calculates the downhole equivalent impact torque with the relative offset at the shoulder of internal and external threads.On the basis of verifying the correctness of the calculation results by using measured results in Well GT1,the prediction model of the downhole equivalent impact torque is formed and applied in the first extra-deep well with a depth over 10000 m in China(Well SDTK1).The results indicate that under complex loads,the stress distribution in drill collar joints is uneven,with relatively higher von Mises stress at the shoulder and the threads close to the shoulder.For 203.2 mm drill collar joints pre-tightened according to the make-up torque recommended by American Petroleum Institute standards,when the downhole equivalent impact torque exceeds 65 kN·m,the preload balance of the joint is disrupted,leading to secondary make-up of the joint.As the downhole equivalent impact torque increases,the relative offset at the shoulder of internal and external threads increases.The calculation results reveal that there exists significant downhole impact torque in Well SDTK1 with complex loading environment.It is necessary to use double shoulder collar joints to improve the impact torque resistance of the joint or optimize the operating parameters to reduce the downhole impact torque,and effectively prevent drilling tool failure.
文摘基于Well-being理论对风储混合电力系统进行了充裕度评估。所采用的Well-being充裕度指标中考虑了N-1确定性准则,不仅能计及发电系统的充裕性,还能计及输电系统的充裕性,因此更加合理且适用于发输电系统的充裕度评估。以简单的RBTS(Roy Billinton test system)以及规模稍大的IEEE-RTS79为算例,仿真分析了风电及电池储能系统(battery energy storage system,BESS)并网对电力系统充裕度的影响。结果表明,与风电场的集中布置相比,分散布置更有利于系统的充裕性;BESS对含风电场的电力系统充裕度提升作用明显,在电力系统瞬时备用控制中具有重要的作用。
