MATLAB环境下基于根轨迹法设计迟后补偿器

介绍了基于根轨迹法的迟后补偿器的计算机辅助设计方法 ,给出了用MATLAB编制的函数cclag ,在MATLAB环境下调用该函数 ,就可以设计出所要求的迟后补偿器 。

逐根径迹比较法

根据各探测器中物理量是独立测量的特点和误差平方独立相加原理。建立了一种“逐根径迹比较法”,用来严格比较高能物理实验中径迹重建的各种方法之间的差别。并具体地比较了某一实验的几种重建数据,发现同一实验的不同重建方法之间,重建效率和重建出来的径迹所带的物理量及其分辨率都有一定差别。经过此方法对之进行比较,得出了其中效率较高、能量和位置分辨最好的一种重建方法。

东濮凹陷沙河街组(古近纪)植物活动痕迹类型及其环境与层序地层学意义

植物活动痕迹即根迹,是层序地层学中识别低位期沉积的重要标志。东濮凹陷沙河街组(古近纪)根迹发育,形态各异,可分为A、B、C、D、E五种类型,分别被解释为五类次级沉积环境下的产物。其中A型根迹、B型根迹与河口湾沉积环境相关,前者见于河口湾陆方一侧的河口沙坝(bay head bar),后者则出现于海方一侧易受海浪冲蚀的盐碱凹地。已有资料证明,植物活动痕迹,结合动物活动痕迹和古生物学、沉积学研究,可为判别河口湾沉积环境、层序界面提供重要实据,从而在层序地层学研究和储层沉积环境探索中显示重要作用。

芋儿七的生药学研究

芋儿七为百合科植物延龄草 Trillimtschonoskii Maxim.的干燥根和根茎,又名:鱼儿七、狮儿七、三角七、尸儿七、佛手七、头顶一颗珠.它是著名的太白山七类草药之一,是陕西民间常用的一种止血药.其味甘辛,性温;有祛风、舒肝、活血、止血的功能:主治高血压。

实用果木丰产栽培技术讲座——第一讲 葡萄快速丰产栽培技术(二)

四、定植 （一）定植前的土壤准备 1.深耕熟化土壤:定植前应平整土地,深翻土壤,清除杂草根,熟化改良土壤,为幼树生长创造良好的根迹环境。对于含土少的河滩地、卵石地、砾质戈壁地应进行局部改土,增加土壤成分和施肥,对于粘重的土壤,应加砂改良,增强其通气性,提高排水性能。

Purification and Bioassay of Mouse β NGF Antibody

Anti β NGF antiserum was prepared by immunizing rabbits with purified mouse β NGF. It presented immunopositivity to β NGF on Western blot, resulting in a single band approximately at the molecular weight of 14 kDa. The antiserum was further purified into anti β NGF IgG by affinity chromatography. Chicken embryonic dorsal root ganglia (DRG) were cultured to test the biological activities of β NGF and its antibody.

PM Diagram of the Transfer Function and Its Use in the Design of Controllers

This paper presents an enhanced Root Locus diagram that consists of the representation of the phase and the magnitude of the transfer function G（s） of a system. The magnitude is represented in decibels and the phase is represented by colors. It also presents how to use it to calculate different kinds of controllers. An important characteristic of this diagram is that permits to read the phase and the gain margins directly and the imaginary axis cut represents the Bode diagram. It is also possible to put the grid with damping ratio ξ and frequency ωn.

华南古生代-中生代遗迹化石Rhizocorallium的系统修订与划分

基于国际最新、最权威的Rhizocorallium的系统分类方案,系统搜集中国学者发表的Rhizocorallium论文,结合野外新发现的Rhizocorallium,将中国华南地区的Rhizocorallium修订为2个种(Rhizocorallium jenense,Rhizocorallium commune)和2个亚种(Rhizocorallium commune uliarensis,Rhizocorallium commune problematica)。赞同Knaust(2013)将垂直且具有蹼状构造的U形潜穴Diplocraterion连同Rhizocorallium一起归到Rhizocorallidae遗迹科。

根艺品不要人为地拼接

一件好的根艺作品,首先它应具备一种纯真、朴素的自然美。因为根的艺术,就是艺术家对树根本身的自然形态的慧眼发现与利用,在完成的作品中,应多见根迹,少见雕痕,不见拼接。

甘肃张掖早白垩世彩丘中古土壤的判别、类型和序列特征

古土壤记录了丰富的古气候和古环境信息,然而古土壤受后期地质作用影响常不易被正确地识别。甘肃张掖彩丘是白垩纪早期发育的彩色地层,目前详细的地层序列尚未建立。张掖彩丘表现为红色、黄色、灰色、紫色等多种颜色交替变化,通常被认为是河湖相沉积或洪积相沉积,然而野外考察发现大量的古土壤特征。野外观察识别古土壤主要从根迹、土壤结构和土壤发生层等方面,主要表现为红色根迹或青灰色晕状根迹,半干旱环境下形成的钙质淀积层,土壤在干湿交替环境下形成的粘土滑擦面,土壤发生层之间的过渡边界。本文通过对张掖彩丘地层的系统考察,建立了较为详细的厚760 m的地层序列,根据古土壤的发育特征,识别出14种不同类型的古土壤,整个彩丘地层共计156个古土壤剖面,是独特的古土壤序列。14种古土壤类型与现代土壤类型对照,并与国际土壤分类对比,类比的现代土壤类型主要出现在南亚的亚热带或热带气候条件,说明白垩纪早期比现在更为温暖。根据古土壤发育程度序列,结合古土壤特征和地层特点,将古气候变化分成4个阶段,依次是湿润(0~268 m)、半干旱(268~550 m)、湿润(550~740 m)、干旱(740~760 m)阶段。张掖彩丘古土壤的系统识别和发育程度序列的建立为进一步古气候研究奠定基础。

当代女性先锋性溯源

女性是艺术创作永恒的主题。古往今来,不同时段的女性之美都带有明显的时代印记。从隋唐的＂微胖界＂;再到宋、明、清的＂纸片人＂;从当代艺术中颠覆性的女性形象,再到流行文化中的自拍图像……艺术图像中的女性形象的流变,实际上就是女性的身份认同与社会地位的变迁。而当代女性的独立、自强、坚韧之美也同样能在历史中找到根迹。

Vibration characteristics of bogie hunting motion based on root loci curves

Vibration behaviors of bogie hunting motion contain key information that dominates the dynamic performance of rail vehicles,in which the eigenvalue of each mode reflects the damping ratio and the natural frequency.This paper focuses on the root loci curves of bogie hunting motion,starting from a rigid bogie,then to a bogie with flexible primary suspension.With regard to the rigid bogie,analytical formulas for the eigenvalues,the critical speed as well as the corresponding hunting frequency are derived and verified.While for the flexible bogie,the root loci curves are calculated numerically.The study shows that both free rigid bogie and free wheelset are dynamically unstable at any speed.The critical speed increases with diminished wheel-rail conicity,track gauge,and wheelset and bogie inertia,and with increased wheelbase and wheel radius.The dominating factors such as the stiffness of the primary suspension and the wheel-rail conicity should be optimized for a practical design.The influences of the damping coefficients and the variations of creep coefficients are negligible.The motor suspension affects the root loci curves and the critical speed significantly.Both inappropriate motor suspension design and rigidly suspended motor reduce the critical speed.The increase of critical speed by a motor suspension can only be achieved when the lower natural frequency of the motor-bogie frame-wheelsets system coincides with or is close to the hunting frequency.Special care should be taken for the design of motor suspension,the first is to avoid the decreased damping ratio in a certain speed range below the critical speed and the second is that the variations of parameters should not induce the rapid reduction of the critical speed.The main feature of the present study is that the root loci curves,which are derived as analytical formulas or calculated numerically,are used to study the vibrational behaviors of bogie hunting motion.Both the influencing laws of the dominating parameters and the principles regarding the motor suspension are significant for the stability design of modem railway vehicles which may use innovative structures/materials as well as modem control and monitoring technologies.