He has a more angular figure than his father.

他的体型比他的父亲更显得有棱。

Pittman launched an angular shot across the face of the goal.

皮特曼射出带度越过球门的一脚。

Angular momentum can accompany nonrotational motion.

非旋转的运可能伴随着有。

Adam's angular black handwriting.

有棱有的黑色手写体。

On the basis of traditional quasistatic analytical method, stiffness for angular contact ball bearing of aeroengine is studied.

在传统拟静力学分析方法的基础上,对航空发机接触球轴承刚度进行了研究。

The analytical model of stiffness for angular contact ball bearing of aeroengine is established by the quasistatic analytical method.

通过拟静力学分析方法，可以建立航空发机接触球轴承的刚度分析模型。

The invention discloses a simulating space sailboard torsional vibration control device and a method based on an angular rate gyro.

本发明公开了基于速率陀螺的模拟太空帆板扭转振控制装置与方法。

This criterion is reasonable because it is not expressed in terms of the precessional velocity, but the angular velocity of the permanent rotation.

该判据用永久转速度的大小而不是进速度的大小作为判别准则,较为合理。

The nonlinearity of moment-angle relationship of the beams in a kind of micromachine vibratory angular rate sensor is derived by using energy method.

用能法计算了振轮式微机械速率传感器中梁的力矩一转的非线性关系，分析了在这种非线性影响下的传感器幅频、相频特性。

Discussing measurement parameter error that is caused by the measurement turn-table cross shaft and vertical axis nonorthogonality during opto-electric measurement angular device is tested.

论述了由于测试转台横轴与竖轴不正交,光电测装置在测试转台上作测试试验,产生测参数的误差。

The magnetooptic self-nulled ellipsometer,with ac Farady magnetooptic modulating and phase locking to detect nulled point,has the high abilities of prevent interference and angular recognize.

磁光调制锁相椭偏仪采用交流法拉第磁光调制及相敏检波来检测消光点,具有抗干扰能力强,分辨能力高等优点。

The uniqueness theorem of generalized quasi-analyticity of the infinitely differentiable functions in some closed angular domain is extehded to the functions of several complex variables.

摘要把无穷可微函数类在形闭区域上的唯一性结果推广到了多维情形。

Researchers can precisely measure previously unquantifiable aspects of pitching—everything from the angular velocity of the arm at the shoulder joint to tension on the knees and elbows.

研究者可以精确地测出先前无法化的各种有关投球方面的数据——从肩关节部位手臂移度的速度，到膝盖和手肘的张力。

The contact between welding plate and fixture is treated as constraint in the finite element model of dynamic welding angular distortion simulation for overlayer in CO2 gas arc welding.

摘要采用有限元数值模拟方法研究了CO2气体保护堆焊的变形态过程。为了反映夹具和焊接件的接触状态，将夹具和焊件统一建立有限元模型。

He has a more angular figure than his father.

他体型比他父亲更显得有棱角。

Pittman launched an angular shot across the face of the goal.

皮特曼射出带角度越过球门一脚。

Angular momentum can accompany nonrotational motion.

非旋转运动可能伴随着有角动量。

Adam's angular black handwriting.

亚当有棱有角黑色手写体。

On the basis of traditional quasistatic analytical method, stiffness for angular contact ball bearing of aeroengine is studied.

在传统拟静力学分析方法基础,空发动机角接触球轴承刚度进行了研究。

The analytical model of stiffness for angular contact ball bearing of aeroengine is established by the quasistatic analytical method.

通过拟静力学分析方法，可以建立空发动机角接触球轴承刚度分析模型。

The invention discloses a simulating space sailboard torsional vibration control device and a method based on an angular rate gyro.

本发明公开了基于角率陀螺模拟太空帆板扭转振动控制装置与方法。

This criterion is reasonable because it is not expressed in terms of the precessional velocity, but the angular velocity of the permanent rotation.

该判据用永久转动角度大小而不是进动角度大小作为判别准则,较为合理。

The nonlinearity of moment-angle relationship of the beams in a kind of micromachine vibratory angular rate sensor is derived by using energy method.

用能量法计算了振动轮式微机械角率传感器中梁力矩一转角非线性关系，分析了在这种非线性影响下传感器幅频、相频特性。

Discussing measurement parameter error that is caused by the measurement turn-table cross shaft and vertical axis nonorthogonality during opto-electric measurement angular device is tested.

论述了由于测试转台横轴与竖轴不正交,光电测角装置在测试转台作测试试验,产生测量参数误差。

The magnetooptic self-nulled ellipsometer,with ac Farady magnetooptic modulating and phase locking to detect nulled point,has the high abilities of prevent interference and angular recognize.

磁光调制锁相椭偏仪采用交流法拉第磁光调制及相敏检波来检测消光点,具有抗干扰能力强,角分辨能力高等优点。

The uniqueness theorem of generalized quasi-analyticity of the infinitely differentiable functions in some closed angular domain is extehded to the functions of several complex variables.

摘要把无穷可微函数类在角形闭区域唯一性结果推广到了多维情形。

Researchers can precisely measure previously unquantifiable aspects of pitching—everything from the angular velocity of the arm at the shoulder joint to tension on the knees and elbows.

研究者可以精确地测量出先前无法量化各种有关投球方面数据——从肩关节部位手臂移动角度度，到膝盖和手肘张力。

The contact between welding plate and fixture is treated as constraint in the finite element model of dynamic welding angular distortion simulation for overlayer in CO2 gas arc welding.

摘要采用有限元数值模拟方法研究了CO2气体保护堆焊角变形动态过程。为了反映夹具和焊接件接触状态，将夹具和焊件统一建立有限元模型。

He has a more angular figure than his father.

体型比亲更显得有棱角。

Pittman launched an angular shot across the face of the goal.

皮特曼射出带角度越过球门一脚。

Angular momentum can accompany nonrotational motion.

非旋转运动可能伴随着有角动量。

Adam's angular black handwriting.

亚当有棱有角黑色手写体。

On the basis of traditional quasistatic analytical method, stiffness for angular contact ball bearing of aeroengine is studied.

在传统拟静力学分析方法基础上,对航空发动机角接触球轴刚度进行了研究。

The analytical model of stiffness for angular contact ball bearing of aeroengine is established by the quasistatic analytical method.

通过拟静力学分析方法，可以建立航空发动机角接触球轴刚度分析模型。

The invention discloses a simulating space sailboard torsional vibration control device and a method based on an angular rate gyro.

本发明公开了基于角速率陀螺模拟太空帆板扭转振动控制装置与方法。

This criterion is reasonable because it is not expressed in terms of the precessional velocity, but the angular velocity of the permanent rotation.

该判据用永久转动角速度大小而不是进动角速度大小作为判别准则,较为合理。

The nonlinearity of moment-angle relationship of the beams in a kind of micromachine vibratory angular rate sensor is derived by using energy method.

用能量法计算了振动轮式微机械角速率传感器中梁力矩一转角非线性关系，分析了在这种非线性影响下传感器幅频、相频特性。

Discussing measurement parameter error that is caused by the measurement turn-table cross shaft and vertical axis nonorthogonality during opto-electric measurement angular device is tested.

论述了由于测试转台横轴与竖轴不正交,光电测角装置在测试转台上作测试试验,产生测量参数误差。

The magnetooptic self-nulled ellipsometer,with ac Farady magnetooptic modulating and phase locking to detect nulled point,has the high abilities of prevent interference and angular recognize.

磁光调制锁相椭偏仪采用交流法拉第磁光调制及相敏检波来检测消光点,具有抗干扰能力强,角分辨能力高等优点。

The uniqueness theorem of generalized quasi-analyticity of the infinitely differentiable functions in some closed angular domain is extehded to the functions of several complex variables.

摘要把无穷可微函数类在角形闭区域上唯一性结果推广到了多维情形。

Researchers can precisely measure previously unquantifiable aspects of pitching—everything from the angular velocity of the arm at the shoulder joint to tension on the knees and elbows.

研究者可以精确地测量出先前无法量化各种有关投球方面数据——从肩关节部位手臂移动角度速度，到膝盖和手肘张力。

The contact between welding plate and fixture is treated as constraint in the finite element model of dynamic welding angular distortion simulation for overlayer in CO2 gas arc welding.

摘要采用有限元数值模拟方法研究了CO2气体保护堆焊角变形动态过程。为了反映夹具和焊接件接触状态，将夹具和焊件统一建立有限元模型。

He has a more angular figure than his father.

他体型比他父亲更显得有棱角。

Pittman launched an angular shot across the face of the goal.

皮特曼射出带角度越过球门一脚。

Angular momentum can accompany nonrotational motion.

非旋转运动可能伴随着有角动量。

Adam's angular black handwriting.

亚当有棱有角黑色手写体。

On the basis of traditional quasistatic analytical method, stiffness for angular contact ball bearing of aeroengine is studied.

在传统拟静力学分析方法础上,对航空发动机角接触球轴承刚度进行了研究。

The analytical model of stiffness for angular contact ball bearing of aeroengine is established by the quasistatic analytical method.

通过拟静力学分析方法，可以建立航空发动机角接触球轴承刚度分析模型。

The invention discloses a simulating space sailboard torsional vibration control device and a method based on an angular rate gyro.

本发明公开了于角速率陀螺模拟太空帆板扭转振动控制装置与方法。

This criterion is reasonable because it is not expressed in terms of the precessional velocity, but the angular velocity of the permanent rotation.

该判据用永久转动角速度大小而不是进动角速度大小作为判别准则,较为合理。

The nonlinearity of moment-angle relationship of the beams in a kind of micromachine vibratory angular rate sensor is derived by using energy method.

用能量法计算了振动轮式微机械角速率传感器中梁力矩一转角非线性关系，分析了在这种非线性影响下传感器幅频、相频特性。

Discussing measurement parameter error that is caused by the measurement turn-table cross shaft and vertical axis nonorthogonality during opto-electric measurement angular device is tested.

论述了由于测试转台横轴与竖轴不正交,光电测角装置在测试转台上作测试试验,产生测量参数误差。

The magnetooptic self-nulled ellipsometer,with ac Farady magnetooptic modulating and phase locking to detect nulled point,has the high abilities of prevent interference and angular recognize.

磁光调制锁相椭偏仪采用交流法拉第磁光调制及相敏检波来检测消光点,具有抗干扰能力强,角分辨能力高等优点。

The uniqueness theorem of generalized quasi-analyticity of the infinitely differentiable functions in some closed angular domain is extehded to the functions of several complex variables.

摘要把无穷可微函数类在角形闭区域上唯一性结果推广到了多维情形。

Researchers can precisely measure previously unquantifiable aspects of pitching—everything from the angular velocity of the arm at the shoulder joint to tension on the knees and elbows.

研究者可以精确地测量出先前无法量化各种有关投球方面数据——从肩关节部位手臂移动角度速度，到膝盖和手肘张力。

The contact between welding plate and fixture is treated as constraint in the finite element model of dynamic welding angular distortion simulation for overlayer in CO2 gas arc welding.

摘要采用有限元数值模拟方法研究了CO2气体保护堆焊角变形动态过程。为了反映夹具和焊接件接触状态，将夹具和焊件统一建立有限元模型。

He has a more angular figure than his father.

他的体型比他的父亲更显得有棱。

Pittman launched an angular shot across the face of the goal.

皮特曼射出带度越过球门的一脚。

Angular momentum can accompany nonrotational motion.

非旋转的运动可能伴随着有动量。

Adam's angular black handwriting.

亚当有棱有的黑色手写体。

On the basis of traditional quasistatic analytical method, stiffness for angular contact ball bearing of aeroengine is studied.

在传统拟静力学分析方法的基础上,对航空发动机接触球轴承刚度进行了研究。

The analytical model of stiffness for angular contact ball bearing of aeroengine is established by the quasistatic analytical method.

通过拟静力学分析方法，可以建立航空发动机接触球轴承的刚度分析模型。

The invention discloses a simulating space sailboard torsional vibration control device and a method based on an angular rate gyro.

本发明公开了基于速率陀螺的模拟太空帆板扭转振动控制装置与方法。

This criterion is reasonable because it is not expressed in terms of the precessional velocity, but the angular velocity of the permanent rotation.

该判据用永久转动速度的大小而不是进动速度的大小作为判别准则,较为合理。

The nonlinearity of moment-angle relationship of the beams in a kind of micromachine vibratory angular rate sensor is derived by using energy method.

用能量法计算了振动轮式微机械速率传感器中梁的力矩一转的非线性关系，分析了在这种非线性影响下的传感器幅频、相频特性。

Discussing measurement parameter error that is caused by the measurement turn-table cross shaft and vertical axis nonorthogonality during opto-electric measurement angular device is tested.

论述了由于测试转台横轴与竖轴不正交,光电测装置在测试转台上作测试试验,产生测量参数的误差。

The magnetooptic self-nulled ellipsometer,with ac Farady magnetooptic modulating and phase locking to detect nulled point,has the high abilities of prevent interference and angular recognize.

磁光调制锁相椭仪采用交流法拉第磁光调制及相敏检波来检测消光点,具有抗干扰能力强,分辨能力高等优点。

The uniqueness theorem of generalized quasi-analyticity of the infinitely differentiable functions in some closed angular domain is extehded to the functions of several complex variables.

摘要把无穷可微函数类在形闭区域上的唯一性结果推广到了多维情形。

Researchers can precisely measure previously unquantifiable aspects of pitching—everything from the angular velocity of the arm at the shoulder joint to tension on the knees and elbows.

研究者可以精确地测量出先前无法量的各种有关投球方面的数据——从肩关节部位手臂动度的速度，到膝盖和手肘的张力。

The contact between welding plate and fixture is treated as constraint in the finite element model of dynamic welding angular distortion simulation for overlayer in CO2 gas arc welding.

摘要采用有限元数值模拟方法研究了CO2气体保护堆焊的变形动态过程。为了反映夹具和焊接件的接触状态，将夹具和焊件统一建立有限元模型。

He has a more angular figure than his father.

他体型比他父亲更显得有棱。

Pittman launched an angular shot across the face of the goal.

皮特曼射出带度越过一脚。

Angular momentum can accompany nonrotational motion.

非旋转运动可能伴随着有动量。

Adam's angular black handwriting.

亚当有棱有黑色手写体。

On the basis of traditional quasistatic analytical method, stiffness for angular contact ball bearing of aeroengine is studied.

在传统拟静力学分析方法基础上,对航空发动机接触轴承刚度进行了研究。

The analytical model of stiffness for angular contact ball bearing of aeroengine is established by the quasistatic analytical method.

通过拟静力学分析方法，可以建立航空发动机接触轴承刚度分析模型。

The invention discloses a simulating space sailboard torsional vibration control device and a method based on an angular rate gyro.

本发明公开了基于陀螺模拟太空帆板扭转振动控制装置与方法。

This criterion is reasonable because it is not expressed in terms of the precessional velocity, but the angular velocity of the permanent rotation.

该判据用永久转动度大小而不是进动度大小作为判别准则,较为合理。

The nonlinearity of moment-angle relationship of the beams in a kind of micromachine vibratory angular rate sensor is derived by using energy method.

用能量法计算了振动轮式微机械传感器中梁力矩一转非线性关系，分析了在这种非线性影响下传感器幅频、相频特性。

Discussing measurement parameter error that is caused by the measurement turn-table cross shaft and vertical axis nonorthogonality during opto-electric measurement angular device is tested.

论述了由于测试转台横轴与竖轴不正交,光电测装置在测试转台上作测试试验,产生测量参数误差。

The magnetooptic self-nulled ellipsometer,with ac Farady magnetooptic modulating and phase locking to detect nulled point,has the high abilities of prevent interference and angular recognize.

磁光调制锁相椭偏仪采用交流法拉第磁光调制及相敏检波来检测消光点,具有抗干扰能力强,分辨能力高等优点。

The uniqueness theorem of generalized quasi-analyticity of the infinitely differentiable functions in some closed angular domain is extehded to the functions of several complex variables.

摘要把无穷可微函数类在形闭区域上唯一性结果推广到了多维情形。

Researchers can precisely measure previously unquantifiable aspects of pitching—everything from the angular velocity of the arm at the shoulder joint to tension on the knees and elbows.

研究者可以精确地测量出先前无法量化各种有关投方面数据——从肩关节部位手臂移动度度，到膝盖和手肘张力。

The contact between welding plate and fixture is treated as constraint in the finite element model of dynamic welding angular distortion simulation for overlayer in CO2 gas arc welding.

摘要采用有限元数值模拟方法研究了CO2气体保护堆焊变形动态过程。为了反映夹具和焊接件接触状态，将夹具和焊件统一建立有限元模型。

He has a more angular figure than his father.

他的体型比他的父亲更显得有棱角。

Pittman launched an angular shot across the face of the goal.

皮特曼射出带角度越过球门的一脚。

Angular momentum can accompany nonrotational motion.

非旋转的运动可能伴随着有角动量。

Adam's angular black handwriting.

亚当有棱有角的黑色手写体。

On the basis of traditional quasistatic analytical method, stiffness for angular contact ball bearing of aeroengine is studied.

在传统拟静力学分法的基础上,对航空发动机角接触球轴承刚度进行了研究。

The analytical model of stiffness for angular contact ball bearing of aeroengine is established by the quasistatic analytical method.

通过拟静力学分法，可以建立航空发动机角接触球轴承的刚度分模型。

The invention discloses a simulating space sailboard torsional vibration control device and a method based on an angular rate gyro.

本发明公开了基于角速率陀螺的模拟太空帆板扭转振动控制装置与法。

This criterion is reasonable because it is not expressed in terms of the precessional velocity, but the angular velocity of the permanent rotation.

该判据用永久转动角速度的大小而不是进动角速度的大小作为判别准则,较为合理。

The nonlinearity of moment-angle relationship of the beams in a kind of micromachine vibratory angular rate sensor is derived by using energy method.

用能量法计算了振动轮式微机械角速率传感器中梁的力矩一转角的非线性关系，分了在这种非线性影响下的传感器幅频、相频特性。

Discussing measurement parameter error that is caused by the measurement turn-table cross shaft and vertical axis nonorthogonality during opto-electric measurement angular device is tested.

论述了由于测试转台横轴与竖轴不正交,光电测角装置在测试转台上作测试试验,产生测量参数的误差。

The magnetooptic self-nulled ellipsometer,with ac Farady magnetooptic modulating and phase locking to detect nulled point,has the high abilities of prevent interference and angular recognize.

磁光调制锁相椭偏仪采用交流法拉第磁光调制及相敏检波来检测消光点,具有抗干扰能力强,角分辨能力高等优点。

The uniqueness theorem of generalized quasi-analyticity of the infinitely differentiable functions in some closed angular domain is extehded to the functions of several complex variables.

摘要把无穷可微函数类在角形闭区域上的唯一性结果推广到了多维情形。

Researchers can precisely measure previously unquantifiable aspects of pitching—everything from the angular velocity of the arm at the shoulder joint to tension on the knees and elbows.

研究者可以精确地测量出先前无法量化的各种有关投球面的数据——从肩关节部位手臂移动角度的速度，到膝盖和手肘的张力。

The contact between welding plate and fixture is treated as constraint in the finite element model of dynamic welding angular distortion simulation for overlayer in CO2 gas arc welding.

摘要采用有限元数值模拟法研究了CO2气体保护堆焊的角变形动态过程。为了反映夹具和焊接件的接触状态，将夹具和焊件统一建立有限元模型。

He has a more angular figure than his father.

他的体型比他的父亲更显得有棱角。

Pittman launched an angular shot across the face of the goal.

皮特曼射出带角度越过球门的一脚。

Angular momentum can accompany nonrotational motion.

非旋转的运动可能伴随着有角动量。

Adam's angular black handwriting.

亚当有棱有角的黑色手写体。

On the basis of traditional quasistatic analytical method, stiffness for angular contact ball bearing of aeroengine is studied.

在传统拟静力学分析方法的基础上,对空发动机角接触球轴承刚度进行了研究。

The analytical model of stiffness for angular contact ball bearing of aeroengine is established by the quasistatic analytical method.

通过拟静力学分析方法，可以空发动机角接触球轴承的刚度分析模型。

The invention discloses a simulating space sailboard torsional vibration control device and a method based on an angular rate gyro.

本发明公开了基于角速率陀螺的模拟太空帆板扭转振动控制装置与方法。

This criterion is reasonable because it is not expressed in terms of the precessional velocity, but the angular velocity of the permanent rotation.

该判据用永久转动角速度的大小而不是进动角速度的大小作为判别准则,较为合理。

The nonlinearity of moment-angle relationship of the beams in a kind of micromachine vibratory angular rate sensor is derived by using energy method.

用能量法计算了振动轮式微机械角速率传感器中梁的力矩一转角的非线性关系，分析了在这种非线性影响下的传感器幅频、相频特性。

Discussing measurement parameter error that is caused by the measurement turn-table cross shaft and vertical axis nonorthogonality during opto-electric measurement angular device is tested.

论述了由于测试转台横轴与竖轴不正交,光电测角装置在测试转台上作测试试验,产生测量参数的误差。

The magnetooptic self-nulled ellipsometer,with ac Farady magnetooptic modulating and phase locking to detect nulled point,has the high abilities of prevent interference and angular recognize.

磁光调制锁相椭偏仪采用交流法拉第磁光调制及相敏检波来检测消光点,具有抗干扰能力强,角分辨能力高等优点。

The uniqueness theorem of generalized quasi-analyticity of the infinitely differentiable functions in some closed angular domain is extehded to the functions of several complex variables.

摘要把无穷可微函数类在角形闭区域上的唯一性结果推广到了多维情形。

Researchers can precisely measure previously unquantifiable aspects of pitching—everything from the angular velocity of the arm at the shoulder joint to tension on the knees and elbows.

研究者可以精确地测量出先前无法量化的各种有关投球方面的数据——从肩关节部位手臂移动角度的速度，到膝盖和手肘的张力。

The contact between welding plate and fixture is treated as constraint in the finite element model of dynamic welding angular distortion simulation for overlayer in CO2 gas arc welding.

摘要采用有限元数值模拟方法研究了CO2气体保护堆焊的角变形动态过程。为了映夹具和焊接件的接触状态，将夹具和焊件统一有限元模型。

He has a more angular figure than his father.

他体型比他父亲更显得有棱角。

Pittman launched an angular shot across the face of the goal.

皮特曼射出带角度越过球门一脚。

Angular momentum can accompany nonrotational motion.

非旋转运动可能伴随着有角动量。

Adam's angular black handwriting.

亚当有棱有角黑色手写体。

On the basis of traditional quasistatic analytical method, stiffness for angular contact ball bearing of aeroengine is studied.

在传统拟静力学分析方法础上,对航空发动机角接触球轴承刚度进行了研究。

The analytical model of stiffness for angular contact ball bearing of aeroengine is established by the quasistatic analytical method.

通过拟静力学分析方法，可以建立航空发动机角接触球轴承刚度分析模型。

The invention discloses a simulating space sailboard torsional vibration control device and a method based on an angular rate gyro.

本发明公开了于角速率陀螺模拟太空帆板扭转振动控制装置与方法。

This criterion is reasonable because it is not expressed in terms of the precessional velocity, but the angular velocity of the permanent rotation.

该判据用永久转动角速度大小而不是进动角速度大小作为判别准则,较为合理。

The nonlinearity of moment-angle relationship of the beams in a kind of micromachine vibratory angular rate sensor is derived by using energy method.

用能量法计算了振动轮式微机械角速率传感器中梁力矩一转角非线性关系，分析了在这种非线性影响下传感器幅频、相频特性。

Discussing measurement parameter error that is caused by the measurement turn-table cross shaft and vertical axis nonorthogonality during opto-electric measurement angular device is tested.

论述了由于测试转台横轴与竖轴不正交,光电测角装置在测试转台上作测试试验,产生测量参数误差。

The magnetooptic self-nulled ellipsometer,with ac Farady magnetooptic modulating and phase locking to detect nulled point,has the high abilities of prevent interference and angular recognize.

磁光调制锁相椭偏仪采用交流法拉第磁光调制及相敏检波来检测消光点,具有抗干扰能力强,角分辨能力高等优点。

The uniqueness theorem of generalized quasi-analyticity of the infinitely differentiable functions in some closed angular domain is extehded to the functions of several complex variables.

摘要把无穷可微函数类在角形闭区域上唯一性结果推广到了多维情形。

Researchers can precisely measure previously unquantifiable aspects of pitching—everything from the angular velocity of the arm at the shoulder joint to tension on the knees and elbows.

研究者可以精确地测量出先前无法量化各种有关投球方面数据——从肩关节部位手臂移动角度速度，到膝盖和手肘张力。

The contact between welding plate and fixture is treated as constraint in the finite element model of dynamic welding angular distortion simulation for overlayer in CO2 gas arc welding.

摘要采用有限元数值模拟方法研究了CO2气体保护堆焊角变形动态过程。为了反映夹具和焊接件接触状态，将夹具和焊件统一建立有限元模型。