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Search Results: 1 - 10 of 126482 matches for " 孙文涛 "
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差示旋光法对VC含量的测定及分析
Differential Polarimetry Measurement and Analysis of the Content of VC
 [PDF]

孙宝良, 孙文
Journal of Advances in Physical Chemistry (JAPC) , 2012, DOI: 10.12677/JAPC.2012.12003
Abstract:
维生素C的含量测定主要有碘量法、分光光度法、旋光法、高效液相色谱法、薄层扫描法等多种测量方法,其中碘量法测量过程较为繁琐,且不易排除辅料对维生素C复方制剂的干扰[1];而分光光度法、高效液相色谱法、薄层扫描法等对测量仪器要求较高,加大了检测成本[1]。本文应用物理学方法,借助于线性回归理论,利用维生素C在不同pH的溶液中其旋光度有显著差异,并且其差示旋光度和浓度在一定范围内呈线性关系的特点,通过差示旋光法对VC注射液的含量进行测定,同时对实验的有关影响因素进行研究分析。结果表明VC注射液在2.50 mg/ml~12.5 mg/ml范围内浓度与差示旋光度的线性关系良好,得到的相关方程为y = 0.1835x + 0.0113,相关系数r = 0.996。对比其他测量方法,该方法简单可靠,结果合理,从而达到快速、简便、准确的测定VC含量的目的,尤其适用于中小医院相关科室对药物的快速检测。
Determination of vitamin C content of the main iodometry, spectrophotometry, polarimetry, HPLC, TLC scanning method and other methods of measurement, iodometric method for the measurement process is more cumber-some and difficult to exclude excipients vitamin C compound interference; higher spectrophotometry, HPLC, TLC scan-ning method of measuring instruments, and increased testing costs. In this paper, methods of physics, by means of linear regression theory, the use of vitamin C in different pH solution in the optical rotation were significantly different, and the differential characteristics of the optical rotation and a linear relationship between concentration within a certain range, by difference show the polarimetry VC injection of content were measured at the same time to study and analyze the influencing factors of the experiment. The results show that the VC injection in 2.50 mg/ml. To 12.5 mg/ml concentra-tion and differential optical rotation of the linear relationship, the related equation y = 0.1835 x + 0.0113, the correlation coefficient r = 0.996. Compared with other measurement methods, the method is simple and reliable, the result is rea-sonable, so as to achieve fast, simple and accurate determination of the purpose of the VC content, especially for small and medium-sized hospital departments for the rapid detection of drugs.
关于点爆炸震源产生的地震子波
肖建华,孙文
石油地球物理勘探 , 1997,
Abstract: ?运用弹塑性理论对点爆炸震源邻域进行理论分析,导出了更符合实际的退缩球腔激发瞬时震源的应力边界条件。在此边界条件下求解波动方程的定解问题,获得了地震子波的解析解。这一理论地震子波较好地解释了地震勘探中实际观测到的地震子波特性,从而改善了对雷克子波形成机制的认识。该成果不仅对地震勘探有实用价值,而且对处理其它形式的瞬时震源问题也有一定的理论意义。
THE POSTPROCESSING FOR GALERKIN METHODS METHODS FOR MISCIBLE DISPLACEMENT PROBLEMS IN POROUS MEDIA
关于多孔介质可混溶流体Galerkin方法后处理

Wen Tao SUN,
孙文

系统科学与数学 , 1997,
Abstract: Professor Lin Qun has put forward an interpolated finite element method. This method is very powerful to improve the global convergence in second order elliptic boundary value problems. This paper uses the method to the Galerkin methods for numerical approximation of the coupled quasilinear system and obtains globally a one order higher convergence.
HD4070PR自动变速器主油压调节方法及意义的研究
孙文,陈慧岩
兵工学报 , 2009,
Abstract: ?通过介绍电控自动变速器调节主油压的原理,并在建立离合器结合过程模型的基础上,分析了自动变速器在不同档位下传递转矩的不同以及主油压对换档过程产生的影响,提出了对主油压进行调节的必要性。通过对HD4070PR自动变速器电控液压系统的分析,获得了其调节主油压的原理以及方法。最后通过试验的方式对其调节技术进行验证,并通过数据分析了主油压的调节对换档品质的改善。
电控自动变速器换挡过程控制策略
孙文,陈慧岩
农业机械学报 , 2008,
Abstract: 为了提高电控自动变速器的换挡品质,通过分析自动变速器的换挡过渡过程,建立了行星式自动变速器动力学模型,并应用此模型对换挡过程进行了详细分析,得到换挡过渡过程的变化规律,同时对离合器充放油规律进行了研究,并采用PWM控制电磁阀对离合器充放油压力进行调节。在换挡过程中,系统先后采用了开环控制、斜率控制以及基于增量PID算法的闭环控制,同时改变发动机喷油量对换挡过程进行了控制。通过试验可以看出换挡过程中采用的开环控制、斜率控制以及基于增量PID算法的闭环控制以及发动机喷油量的控制策略改善了换挡品质。
岩溶隧道在SH波激励下动力响应位移解析解
Displacement analytical solutions of dynamic response of karst tunnel subjected to SH waves

臧万军,孙文
- , 2018, DOI: 10.7511/dllgxb201802008
Abstract: 基于工程波动理论,利用波函数展开法和Fourier-Bessel级数变换,推导了岩溶隧道在平面SH波激励下动力响应位移解析解的计算公式,并提出实用的简化解.通过数值模拟解验证了该动力响应位移解析解的合理性,两种解法在入射角度为0°和90°时溶洞与隧道的位移幅值峰值均相差10%左右.研究了溶洞半径、平面SH波入射角度以及溶洞与隧道间的中心距等3个影响因素对溶洞和隧道的动力响应作用,结果表明:溶洞和隧道位移幅值与溶洞半径成正比,与两者间的中心距成反比,与平面SH波入射角度成正比.
Based on the engineering wave theory, displacement analytical solutions are derived for the dynamic response of a karst tunnel subjected to SH waves with the wave function expansion method and Fourier-Bessel series transformation, and a practical simplified solution is proposed. The rationality of which is verified by numerical simulation solution. The differences of displacement amplitude peak value of the karst cave and the tunnel are about 10% between the two methods when the incident angles are 0° and 90°. The dynamic response effects of three factors, such as the radius of karst cave, the incident angle of plane SH wave and the center distance between karst cave and tunnel, are studied. The results show that the displacement amplitude values of the karst cave and the tunnel are proportional to the radius of karst cave, are inversely proportional to the center distance between the karst cave and the tunnel, and are proportional to the plane SH wave incident angle.
高压直流输电系统中次同步振荡研究综述
Studies of Sub-Synchronous Oscillation in HVDC System
 [PDF]

韩松, 祁万春, 蔡晖, 高山, 孙文, 窦飞, 赵欣
Transmission and Distribution Engineering and Technology (TDET) , 2016, DOI: 10.12677/TDET.2016.52002
Abstract:
由于高压直流输电(HVDC)技术有着损耗小、线路造价低等优点,在我国电力系统中被广泛采用。但HVDC与汽轮发电机组轴系相互作用可能产生次同步振荡(SSO),影响系统的安全稳定运行。本文以直流输电系统对次同步振荡的影响和抑制方法为立足点,对高压直流输电系统中次同步振荡研究进行综述。首先,比较了几种常用的HVDC数学建模方法。然后,总结了换流器触发方式、控制模式及控制参数等对次同步振荡的影响,并介绍了多直流运行、串补或其他电气设备与HVDC联合运行时的系统的次同步振荡特性。接着指出在HVDC整流侧的定电流控制器里附加次同步阻尼控制是一种最常用的抑制SSO的策略,并比较了常见SSDC的设计方法。本文还介绍了新型直流输电VSC-HVDC以及风电加入系统后对次同步振荡的影响。最后,结合电力系统的发展要求对高压直流输电系统的次同步振荡研究方向做出展望。
HVDC has been applied widely in power systems because it has some merits such as low loss, low line cost and so on. However, interaction between HVDC converters and turbine generator shaft system may cause subsynchronous oscillation (SSO) which threats the safety and stability of power systems. This paper is intended to make a survey on SSO in HVDC by proceeding from the influence of HVDC on SSO and corresponding suppression strategy. The common methods of HVDC mathematical modeling are compared first. Secondly, the paper summarizes the effect of HVDC converter trigger modes, control modes and control parameters on SSO. The SSO characteristics of multiple HVDC and HVDC combined operation with series compensation or other electrical equipment is also introduced. Then the most common suppressing strategy that is installing a supplementary subsynchronous damping control (SSDC) in the constant current controller of rectifier is pointed out. And the design approaches of SSDC are compared. Besides, the influences of VSC-HVDC and HVDC system including wind power on SSO are presented. Finally, vistas of research are projected into the future.
电位滴定法测定金属腐蚀产物清洗液中的氯离子
孙文,孙成,向仁英,张平健
腐蚀科学与防护技术 , 1991,
Abstract: 一、前言 众所周知,金属腐蚀产物相当复杂,对其中氯离子的监测是很重要的一项指标。通常测定水溶液中氯离子,有银量法、硝酸汞滴定法、直接电位法、电位滴定法以及离子色谱法等。由于金属腐蚀产物清洗液中常常带有颜色,强氧化性,酸度大等特点,通常方法无法测定,本文采用电位滴定法测定金属腐蚀产物清洗液中氯离子,方法简单、快速、准确,结果令人满意。
偶氮氯膦-PN直接光度法测定钴铬铝及铅钇合金中的钇
孙文,赵全华,何永深
腐蚀科学与防护技术 , 1990,
Abstract: <正> 近年来应用不同显色剂并在掩蔽剂存在的条件下,直接光度法测量合金中钇有过许多报导。但对钴铬铝合金中和高含量铝钇合金中的钇的测定尚无报导。本文采用偶氮氯膦-PN与钇形成β型蓝色络合物,在732nm处有最大吸收峰。应用EIDTA、柠檬酸和抗坏血酸联合掩蔽剂,以消除钴(Ⅱ)、铬(Ⅲ)、铝(Ⅲ)、铁(Ⅲ)的干扰。直接光度法具有操作简便,灵敏度高,数据准确的特点。
电位滴定法测定金属腐蚀产物清洗液中的氯离子
孙文,孙成,向仁英,张平健
腐蚀科学与防护技术 , 1991,
Abstract: 一、前言众所周知,金属腐蚀产物相当复杂,对其中氯离子的监测是很重要的一项指标。通常测定水溶液中氯离子,有银量法、硝酸汞滴定法、直接电位法、电位滴定法以及离子色谱法等。由于金属腐蚀产物清洗液中常常带有颜色,强氧化性,酸度大等特点,通常方法无法测定,本文采用电位滴定法测定金属腐蚀产物清洗液中氯离子,方法简单、快速、准确,结果令人满意。
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