A Study of Energy - Saving AC Speed – Governing System with
Electromagnetic Load
CHEN Zheng - shi , LIU Juan XXX
( Maoming College , Maoming 525000 , China)
Abstract : A new kind of variable frequency speed - governing experiment system which has the structure of two parallel inverters at DC bus and output of inverter driving two series asynchronous motors at the same shaft is presented in this paper. The results of the experiment show that this creative AC variable frequency speed - governing experiment
system can : a) realize the load relationship of direct electromagnetic torque betw een the motor group ;b) get the continuous control process easily for the reaction load and potential energy load during four quadrant ; c) achieve the total availability of the regenerated energy at any kind of load. The system’s power consumption makes up under 30 % of actualload power at any kind of load.
Key words : AC speed - governing ;electromagnetic load ; energy saving ; difference frequency 1Development of AC speed – governing
For a long time, because DC Motor Speed superior performance and cover up the shortcomings of complex structures, and other widely used in engineering processes. DC motor rated speed in the following run-time, maintaining a constant current excitation, armature voltage can be used to change the method of achieving a constant torque speed in the rated speed over running and maintaining the armature voltage constant, can be used to change the method excitation constant power transfer Speed. Used speed, double-loop DC converter current system will be an excellent static and dynamic governor characteristics.
Therefore, during the 1980s before the transmission speed in the field, DC converter has been the dominant position. In recent years, the rapid development of science and technology to speed the development of the exchange created a very favorable technical conditions and material basis. AC Motor Speed Control system not only the performance with the performance of DC Motors, and the cost and maintenance costs lower than the DC motor systems, higher reliability.
（1）Modern types of AC Drive System
Modern communication systems from AC Motor Speed, power electronic power converters, controllers and detectors, and other four major components. Power electronic power converters, controllers, power consumption is concentrated in one test, known as the frequency converter (VVVF devices). AC Motor different, and multiply to speed the exchange of different systems. So speed of modern communication systems can be divided into asynchronous motor speed control system and synchronous motor speed regulation system. At present there are three more common programme, which is the exchange of asynchronous motor speed regulation system, SRM exchange system and speed the exchange of permanent magnet synchronous motor speed regulation system. Speed in the design, which is more appropriate to the programme, which required further analysis.
Throughout the development of communication technologies speed, we can see that modern communication technologies speed the development of future trends and developments.
1, intelligent control system to speed the exchange of impact studies.
2, speed control system to improve the efficiency of the exchange method.
3, the pressure Frequency Device research.
4, system reliability studies.
（2）AC Drive System Benefits
For a long time, due to DC converter system performance is better than AC Drive System, DC converter system has been in areas dominated by speed. However, the DC converter system has several shortcomings below.
1, a DC motor drag. DC Motors prone to failure, maintenance difficulties.
2, Use is limited. In flammable, explosive and a poor environment where mining can not.
3, the DC motor of structural factors, so that single speed and capacity constraints, resulting in DC converter system development was limited.
4, DC motor prices, far higher than AC motors.
With electricity, electronic technology development, especially in the development of control technology in recent years, exchanges speed access to the leap in the development. AC Drive System below several major advantages.
1, AC Motor particular cage induction motor prices much lower than the DC motor.
2, AC Motor difficult to failure, maintenance is simple.
3, AC motor there is no restriction on the use of occasions.
4, AC motors can be much greater than the capacity of single DC motor.
Let’s review for a moment some of the various terms as they are used to describe solid-state frequency controllers. There are rigid technical definitions as generally usd terminology. First , the technical definitions as suggested by organizations such as IEC,NEMA, and IEEE(Institute of Electronics Engineers):
(1)Converter :an operative unit for power conversion comprising one or more valve devices(power semiconductors ,for example).
(2)Self-commutated converter: a converter in which the commutation voltages are supplied by components within the converters.
(3)Rectifier: a converter for conversion from AC to DC.
(4)Inverter: a inverter for conversion DC to AC.
(5)Indirect AC converter: a converter comprising a rectifier and an inverter with a DC link.
Form or anther, and definition 5 covers the complete system. However, general usage in the United States is to call it “inverter”: PWM inverter ,adjustable voltage inverter, or current source inverter.
PWM Versus AVI Versus CSI
All three of the most commonly used adjustable-frequency controllers consist of three basic sections. The input section converts the in coming AC power to AC. The center section, or DC link or DC voltage .The output section inverts the DC into AC of AC of the desired frequency. The differences among these three types of controllers are the manner in which the adjustable voltage is obtained, and the technique used to create the adjustable frequency.
PWM
Pulse Width Modulation (PWM) many types of technology, and is constantly developing. Can basically be divided into four categories, namely width PWM, sine PWM, PWM flux-tracking method of tracking PWM and current law. PWM technology to overcome the phased application of the principle of all defects so that the motor stator exchanges have been close to sine-voltage and current, improving the electrical power factor and the power output. Most modern PWM
circuit generated by high output HSO the SCM (80,196) and digital signal processors, software programming generated by PWM. In recent years, new digital PWM generation chips for H F4752, SLE4520, M18, and so achieve practical, and have practical applications
Pulse-width modulation (PWM) utilizes diodes in the input stage to provide a fixed-voltage DC bus. The output ,or inverter stage, creates a series of pulses of constant voltage with the pulse widths and quantities varying as required by the desired by the designed output frequency and voltage. The output section supplies and controls both parameters, adjustable frequency and adjustable voltage.
AVI
Adjustable-voltage inverters(AVI) use thyristors in the stage to obtain adjustable voltage in the DC link. The output stage switches this DC voltage with thyristors or transistors or GTO s to obtain a square-wave whose width and timing sequence control is obtained in the second stage. CSI
Current source inverters(CSI s) are similar to AVIs, except that the control is arranged to provide a series of square waves of current output.
2 The structure and the feature of the system
Fig. 1 shows the principle and structure of this AC experiment system. The work process of traditional AC speed - governing is that variable voltage from frequency converter drives an induction motor which makes generator supply to some loads such as resistor and electric heating element , and then produces the electromagnetic torque on the generator as load torque of motor. But this load torque is balanced by achieving the current power from frequency converter. So the traditional AC speed - governing experiment system is a process of energy consuming.
Fig. 1 AC speed - governing experiment system
The AC speed - governing experiment system , which is shown in Fig. 1 , has been greatly improved at structure. Normal motor - generator are changed into two motors at the same shaft and the two inverters are parallel at DC bus. Then the output of variable frequency current drives the two motors separately. Two inverters can be cont rolled by means of difference frequency. The advantage of this experiment system is not only in the change of structure , but more important is
that the function index , control feature are much more improved , especially for it s characteristic of economical energy. If the loss beyond the motor load is not considered , the experiment result s show a process of regenerate energy being feeded back and utilized totally in fact .
3 Analysis of system principle
3. 1 Form and feature of motor load
The working principle of this system is that both induction motors fixed on single axis are driven by AC differece frequency voltage that are the output s of two inverters by means of setting difference frequency. It can be proved by the analysis of torque feature and parameter expression that the torque of motor one (M1) produced by high frequency voltage is bigger than torque of motor (M2) produced by low frequency voltage. So M1 works at the state of motor (quadrant one) and it s electromagnetic torque is as the main torque to drive M2 , which works at the state of generator (quadrant two) and oversteps the synchronous speed (n > n02) . It is obviously that if the system has the possibility to recover regenerate energy , M2 will produce the electromagnetic torque which has the opposite direction to M1 , and makes motor - generator group get the load relationship of direct electromagnetic torque. Fig. 2 shows each mechanical features of two motors at the corresponding working state , reflect s their load relationship very clearly. We can also see that the system has constant torque performance within fundamental frequency when the voltage frequency of both motors is increased
or decreased in synchrony.
Fig. 2 Mechanical features of two motors
3. 2 Working state analysis of converter
Corresponding to the structure of variable frequency , speed - governing experiment system , both of the motor can be continuously and smoothly transformed between motor and generator , and can work at the steady state , by means of nimbly regulating and cont rolling the output frequency f1 and f2 of two inverters ,in the condition of Δf = | f1 - f2| > 0 (within the limit of maximum motor current) , as in Fig. 2. This can not be realized for any other structure of speed - governing experiment system . The circuit of the inverter is obviously suitable for the requirement to transform the system state. In the case of M1 , if f1 - f2 > 0 , M1 runs at motor state , meanwhile inverter ( I) runs at reverse state , and it s difference of phase angle between phase voltage and phase current is less than 90°. The waveform of voltage and current at the frequency f1 =15Hz , f2 = 12Hz are shown in Fig. 3. if f1 - f2 < 0 , M1 runs at generator state , at the same time inverter
( I)
runs at rectification state and it s difference of phase angle between phase voltage and phase current is more than 90°. The waveform of voltage and current at frequency f1 = 15Hz , f2 = 18Hz are shown in Fig. 4 .Another state must be pointed as f1 = f2 . Virtually M1 and M2 runs all in
motor state with very little of current at the same period. The phase between line voltage and phase current is still less than 90°. Their waveforms are shown in Fig. 5 .Analysed from the waveform , it is directly and clearly shown that variable process of working state which is reverse to rectification or rectification to reverse can be completed during the system state variable process in the inverter , and this is very significant to the experiment research of inverter it self .
Fig. 3 Waveforms of voltage and current Fig. 4 Waveforms of voltage and current
3. 3 Feed- back path and utilization of regenerate energy
I f the load relationship of direct electromagnetic torque between two motors can be kept , the regenerate energy will totally feed back according to Fig. 2. The reverse uncontrolled three - phase bridge composed by extending diode of voltage inverter provides the path for the AC regenerate energy. That is to say , in the supply circuit where motor works at generating state , the function of inverter is changed into rectifier , and AC voltage from generator is converted into DC voltage to common DC bus through parallel reverse diode bridge in the inverter. The direction of DC current at this moment is opposite to the current working at the state of inverter. Because two
inverters use the common uncontrolled three - phase rectifier at line side , the regenerate energy can not turn back to the line side. The direction of DC current at the DC bus side is shown in Fig.
1. It can be seen that the achieving power of inverter (1) comes f rom rectifier and inverter (2) that provide sum of two DC component s , i. e. the consumed power of M1 is the sum of source and the regenerate energy of M
2. In this way ,the regenerate energy of M2 is totally utilized. A conclusion can be drawn through the analysis of torque feature that the electromagnetic torque T2 is opposite to T1 , so this torque can be called analogue load torque of M1. The amount of regenerate energy can be regulated effectively through the control of difference frequency and the continuous speed - governing control under the reference frequency is achieved.
Fig. 5 Waveforms of voltage and current forf1 = f2 state
4 Design of system cont rol unit
According to the synthetical mechanical feature of two motors in Fig. 2 , corresponding feature of balanceload relationship can be got as long as the output variable frequency voltage of two inverters can be cont rolled with difference. To meet the request of system feature and input signal of difference frequency ,a synthetical control unit is specially designed for this system , see Fig. 6. Hardware circuit is composed of chip microprocessor 89C51 , 12 bit D/ A conversion equipment , keyboard , and display unit . A synthetical control program is also designed. The control unit can transmit many modes of analogue frequency signals . It has the function of initialization for difference and parameters modification on line etc. and can make operation for speedgoverning more flexible.
Fig. 6 Hardware circuit of control unit
5 System application and conclusion
This experiment system can a) prove some theories and analysis conclusions for dynamic process of AC variable frequency speed - governing technique in teaching , researching and the other application ;b) give the quantizing evaluation for some concerned special features and index under different loads and conditions ,c) offer the technical reference basis for different kinds of loads to choose and fix AC speed- governing plan. The distinguishing of this system is that analogue load for AC speed - governing experiment system is solved and regenerate energy is realized. The continuous control process during four quadrant under the proportion to the difference frequency of reaction and potential energy load can be got at experiment al condition very easily and the direct understanding of theory for rectifier - reverse - rectifier in the converter can also be achieved because it s creative structure design. The feature and conclusion of the system in this paper has been fully proved. Corresponding experiment data and chart has yet been presented by an experiment system .
〔References〕
〔1〕Yong - que Man ,An - yong Han. General - purpose inverters and application
〔M〕.Beijing :China Mechanical Industry Publishing Press. 1995 ,
107 - 115.
〔2〕N. C. Chio ,S - W. Lee. Low - cost High Power Factor Rectifiers with Slop Control〔C〕. In : Qian Zhaoming , Wu Zhaolin. IPEMC. Beijing :
International Academic Publishers. 1997 : 576 - 579.
〔3〕Chen Zheng - shi. Modified SCR Phase - controlled by Microprocessor.〔C〕In :Wang Ziqiang ,Liu Xuezhi. IPEMC. Beijing : International A2
cademic Publishers. 1994 :706 - 710.
研究能量- AC速度-调速系统节约使用电磁负荷
陈郑-王振耀、刘娟
(茂名学院、茂名:525000)
文摘:提出了一种新型的变频调速实验系统-治理结构的两条平行逆变器直流母线和输出的两个系列异步电动机变频驱动在同一轴进行了阐述。实验结果表明:这种具有创新特色的交流变频调速的控制实验系统可以:a)实现负载关系之间的直接电磁转矩电机集团;b)得到的连续控制过程易为反应负荷或位能负载特性下四象限运行期间,c)达到总有效性的再生能源,任意负载。系统的电源消费做actualload电力的30%以下,任意负载。
关键词:AC速度-控制、电磁负荷;节能环保;不同的频率
1交流的发展速度
长期以来,由于直流电机调速性能优越,掩盖了复杂结构的不足之处,以及其他广泛应用于岩土工程的过程。直流电机额定转速以下运行时,保持恒流激励,电枢电压可以用来改变这个方法,实现一个恒转矩速度超过额定速度运行和维护电枢电压不变,可以用来改变励磁恒功率调速方法。使用速度、电流双闭环直流变流器系统会成为一名优秀的静态和动态州长的特点。
因此,在1980年代在传播速度在田野、直流变流器一直主导地位。近年来,科学技术的迅速发展加快发展创造了一个很好的交流技术条件和物质基础。交流电机调速系统的性能不仅与直流电机的性能,而且成本和维护成本低于直流电机系统,可靠性更高。
(1)现代类型的交流传动系统
现代通信系统中交流电机的速度,电力电子电源转换器、控制器和探测器、和其他四个主要部件。电力电子电源转换器、控制器、功耗都集中在一个测试,称为变频器(VVVF器件)。交流电动机的不同,和繁衍的交换速度不同的系统。所以速度现代通讯系统可分为异步电机的转速控制系统和同步电动机调速系统。目前有三种更常见的程序,就是交流异步电动机调速系统、SRM交换系统和速度的交流永磁同步电动机调速系统。
在设计速度,更适合于这项计划,这要求进一步的分析。
在通信技术的发展速度,我们可以看到,现代通信技术,加快发展未来的趋势和发展。
1、智能控制系统速度影响研究的交换。
2、速度控制系统,提高系统的运行效率的交流方法。
3、压力频率装置的研究。
4、系统可靠性研究。
(2)交流传动系统效益
很长一段时间,由于直流变流器系统性能优于交流传动系统、直流变流器系统已在地区占主地位的速度。然而,直流变流器系统有几个缺点如下。
1语言中,一种直流电机拖动。直流电机容易失败,维护困难。
2、使用是有限的。在易燃、易爆、一个贫穷的环境中挖掘不能。
3、直流电机的结构因素,使单一的速度和容量约束,导致直流变流器系
统的发展受到限制。
4、直流马达的价格,远高于AC马达。
以电力、电子技术的发展,特别是在控制技术的发展,近年来交流的速
度进入飞跃发展。交流传动系统以下几个主要的优点。
1、交流马达特定笼感应电机的价格远远低于直流电机。
2、交流马达很难失败,维护简单。
3、交流马达有任何使用限制的场合。
4、交流电机可以比单一的直流电机的能力。
让我们复习一些等不同条件的时刻,因为他们都是用来描述固态频率控制器。有严格的技术定义术语一般美元。第一,技术的定义提出的组织,如IEC、防灾和电器和电子工程师协会(电子工程师协会):
(1)转换器:一个有效的单位能量变换构成一或更多阀装置(功率半导体,
例如)。
(2)Self-commutated转换器:一个转换器,变换电压均为内组件的转换器。
(3)整流器:一个转换器转换成直流交流。
(4)逆变器:AC逆变器直流转换。
(5)间接的交流变换器:一个转换器包括一个整流器和逆变器直流环节与。
形式或另一个,并定义5涵盖完整的体系。然而,一般使用在美国是称之为“反相器”:PWM逆变器、调的电压逆变器,或电流源变频器。
PWM与AVI和电流源变频器
所有三种最常用的adjustable-frequency控制器包括三个基本的部分。把输入节在即将到来的交流电源AC。中心部分,或直流环节或直流电压。输出部分(AC交流直流到你所期望的频率。
区别这三种控制器的方式得到调节电压,技术用来创建可调频率。
PWM
脉宽调制(PWM)许多类型的技术,并不断发展。基本上就可以分为四种类型,即宽度PWM、正弦脉宽调制PWM脉宽调制和跟踪方法flux-tracking现行法律。
PWM技术,克服了阶段性原则的应用所有的缺陷使电机定子交流已经接近
sine-voltage和电流,提高电力输出功率因素和。大多数现代PWM电路产生的高速输出单元HSO实现高输出配置管理(80196年)和数字信号处理器,通过软件编程产生PWM(脉宽调制)。近年来,新一代数字PWM芯片为H
F4752,SLE4520,M18,从而达到实用,并具有实际应用性。
脉宽调制(PWM)在输入阶段利用二极管提供一个fixed-voltage直流母线。
输出,或逆变阶段,创造了一系列的脉冲电压和脉冲宽度的不断变化和数量的要求设计期望输出频率和电压。输出部分补给和同时控制参数,可调频率和电压可调。
AVI
Adjustable-voltage逆变器(AVI)使用晶闸管在舞台上获得可调直流环节电压。输出级直流电压与晶闸管开关这或电晶体或GTO年代以获得一个方波的宽度和控制时序控制中获得了第二个阶段。
《电流源变频器》
电流源变频器(CSI s)和国际相似,除了那个控制安排提供一系列的平方波电流输出。
2的结构和特点的系统
图1显示了该交流的原理和结构实验系统。传统工作过程控制是交流速度——变压变
频驱动的异步动机使发电机供应等一些负载电阻和电热元件,并产生电磁扭矩负载转矩电机作为发电机。但这负载转矩平衡实现了变频器电流力量。因此,传统的交流速度-控制实验系统是一个过程的能量消耗。
图1 - AC速度控制实验系统
交流速度-控制实验系统。图1显示的是,已经大大提高结构。正常的摩托,发电机就变成两个马达在同一轴和两个平行逆变器直流母线。然后变频电流的输出驱动两个马达另行规定。两个逆变器可以马上滚采用差频。该实验系统的优势,不仅是变化的结构,但是更重要的是,该功能指标,控制特点进行更多的提高,尤其因为它年代的经济特点的能量。如果灭失超出了电机负载不认为,实验结果显示一个过程的年代能量再生利用feeded回被完全的事实。
分析系统的原理
3.1一的形式和特点的电机负载
该系统的工作原理都是固定在异步电动机单轴驱动频率电压交流电differece,逆变器的输出信噪通过设置两种不同的频率。它能经受分析特点和参数表达式转矩电机的转矩的(M1)所产生的高频电压比力矩电机(M2)所产生的低频电压。所以M1作品的状态电机(象限),而且它的电磁转矩为主要扭矩是开车平方米,这是发电机的状态(象限二)同步速度和踩越(n > n02)。很明显,如果系统有可能恢复能量再生(M2)会产生电磁转矩具有相反方向,M1,使电机负载-发电机组得到直接电磁转矩方式的关系。图2显示每个的物理机械性能,两个电动机相应的工作状态,反映年代初,他们负载关系是非常明显的。我们还可以看到,该系统具有恒转矩性能在基本频率当电压的频率增加。两个马达同步或减少。
图2 物理机械性能,两个马达
3.2两个工作状态分析转炉
对应于结构变频率、速度-控制实验系统,两个发动机可以顺利之间不断转换电机和发电机,可以工作在稳定的状态,通过灵活的调节和不断滚的f1和f2的输
出频率两个逆变器的情况下Δf = | f1 - f2 | > 0(极限内最大的电机电流),就
像在图2。这不可能是实现任何其他结构的实验系统速度-治理。逆变电路的显然是适合需要转换系统的状态。M1的情况下,如果f1 - f2 > 0,M1在电机运行状态,同时逆变器(1)跑向反向状态,它是相之间的角度差相电压和相位电流小于90°。电压和电流波形频率= 15赫兹f1,f2 = 12赫兹显示在图3。如果f1,f2 < 0 - M1跑向发电机状态,同时变频器
(I)
跑向整流状态,所以年代相之间的角度差相电压和相位电流超过90°。电压和电流波形频率15例赫兹在f1,f2 = 18赫兹显示,如图4。必须指出另一个国家的f1 = f2。M1和M2分几乎所有国家很少在电机的电流在同一时期。电压相位及相位之间目前仍低于90°。他们的波形图5显示。从波形分析,它是直接、清晰显示工作状态变化过程,这是颠倒反转修正或改正就可以完成在系统状态变量的过程中逆变器,这是非常重要的,它的逆变器实验研究自我。
图3 电压和电流波形图4 电压和电流波形
3.3饲料-背道和利用再生能源
如果负载关系,二者之间的直接电磁转矩电机可以保持再生能源就会完全地反馈根据图2。逆向控制三相
由扩展二极管桥电压逆变交流提供了路径能量再生。也就是说,在电机工程供电线路生成的地方,其功能的逆变器转换成整流器和交流电压转换成直流电压发生器是普通的直流母线通过并行逆向二极管桥变频器。直流电流的方向在这一刻对当前工作的状态变频器。因为两个使用公共控制变频器在三相整流电源侧,再生能源不可以转回线的一面。直流电流的方向的侧直流母线如图。
1.我们可以看出实现逆变器(1)的力量来f罗整流器和逆变器(2)提供的两个直流分量总和年代,即M1消耗功率之和的来源和再生能源平方米。以这种方式,
再生能源利用平方米是完全。一个结论需要通过分析转矩特征,电磁转矩T1与T2,所以这扭矩可称为模拟负载转矩的M1。再生能量的数量可以调节的控制有效地通过差频与持续速度-治理参考频率控制下完成。
图5、电压和电流波形forf1 = f2状态
4系统设计单位
根据综合力学特征的两个马达在图2,对应关系的特点,可以获得balanceload只要输出变量的两个频率电压逆变器可以马上滚与差异。以满足系统的特征和要求输入信号频率的差异,一种综合控制单元,是专门为这个系统,见图6。硬件电路是由微处理器芯片89 C51单片机、12位D / A转换设备、键盘和显示单元。是一种综合控制程序设计。控制单元传送许多模式可以模拟频率信号。它的功能差异和参数初始化等改性,可以在线speedgoverning操作更灵活。
图6 硬件电路控制单元
5 系统的应用和结论
该实验系统能证明某些理论和分析)的动态过程的结论的交流变频调速技术在百年前教学、科研和其他应用;(2)给量化评价特点和有关指标在不同载荷及条件,c)提供技术参考依据,对不同类型的选择和固定负载管理计划速度-交流。摘要本系统模拟负载,AC速度-控制实验系统和再生能源解决的实现。连续控制过程的四象限比例下差频的反应或位能负载特性下,可以获得最佳状态很容易在实验和理论的直接的理解整流器在转炉整流器逆转也能达到创造性,因为它年代结构的设计。特征和结论本文体系已经充分的证明。相应的实验数据和图表尚未提出了通过实验系统。
【参考文献】
Exploring Filipino School Counselors’ Beliefs about Learning Allan B. I. Bernardo [Abstract] School reform efforts that focus on student learning require school counselors to take on important new roles as advocates of student learning and achievement.But how do school counselors understand the process of learning? In this study, we explore the learning beliefs of 115 Filipino school counselors who indicated their degree of agreementwith 42 statements about the process of learning and the factors thatinfluence this process.A principal components analysis of the responses to the 42 statements suggested three factors:(F1)social-cognitive constructivist beliefs, (F2) teacher-curriculum-centered behaviorist beliefs,and (F3) individual difference factors.The preliminary results are briefly discussed in terms of issues related to how Filipino school counselors’ conceptions of learning may guide their strategies for promoting student learning and achievement. [Key words]beliefs about learning, conceptions of learning, school counselors, student learning, Philippines School reform efforts in different parts of the world have focusedon students’learning. In particular,most school improvement programsnow aim to ensure that students acquire the high-level knowledge and skills that help them to thrive in today’s highly competitive globaleconomy (e.g., Lee & Williams, 2006). I n this regard, school reform programs draw from various contemporary theories and research on learning (e.g.,Bransford,Brown, & Cocking, 1999; Lambert & McCombs, 1998).The basic idea is that all school improvement efforts should be directed at ensuring students achieve high levels of learning or attainment of well-defined curricular objectives and standards.For example, textbooks (Chien & Young, 2007), computers and educational technology (Gravoso, 2002; Haertnel & Means, 2003;Technology in Schools Task Force, 2003), and educational assessment systems (Black & Wiliam2004; Cheung & Ng, 2007; Clark, 2001; Stiggins, 2005) are being reconsidered as regards how they can effectively provide scaffolds and resources for advancing student learning. Likewise,the allocation and management of a school’s financial resources are assessed in terms ofwhether these are effectively mobilized and utilized towards improving student learning (Bolam, 2006; Chung & Hung, 2006; Retna, 2007). In this regard, some advocates have also called for an examination of the role of school counselors in these reform efforts (Herr, 2002). Inthe United States, House and Hayes (2002) challenged school counselors to take proactive leadership roles in advocating for the success of all
第四单元给水系统 一般来说，供水系统可划分为四个主要组成部分:（1）水源和取水工程（2）水处理和存储（3）输水干管和配水管网。常见的未处理的水或者说是原水的来源是像河流、湖泊、泉水、人造水库之类的地表水源以及像岩洞和水井之类的地下水源。修建取水构筑物和泵站是为了从这些水源中取水。原水通过输水干管输送到自来水厂进行处理并且处理后的出水储存到清水池。处理的程度取决于原水的水质和出水水质要求。有时候，地下水的水质是如此的好以至于在供给给用户之前只需消毒即可。由于自来水厂一般是根据平均日需求流量设计的，所以，清水池为水需求日变化量提供了一个缓冲区。 水通过输水干管长距离输送。如果输水干管中的水流是通过泵所产生的压力水头维持的，那么我们称这个干管为增压管。另外，如果输水干管中的水流是靠由于高差产生的可获得的重力势能维持的，那么我们称这个干管为重力管。在输水干管中没有中间取水。与输水干管类似，在配水管网中水流的维持要么靠泵增压，要么靠重力势能。一般来说，在平坦地区，大的配水管网中的水压是靠泵提供的，然而，在不平坦的地区，配水管网中的压力水头是靠重力势能维持的。 一个配水管网通过引入管连接配水给用户。这样的配水管网可能有不同的形状，并且这些形状取决于这个地区的布局。一般地，配水管网有环状或枝状的管道结构，但是，根据当地城市道路和街区总体布局计划，有时候环状和枝状结构合用。城市配水管网大多上是环状形式，然而，乡村地区的管网是枝状形式。由于供水服务可靠性要求高，环状管网优于枝状管网。 配水管网的成本取决于对管网的几何形状合适的选择。城市计划采用的街道布局的选择对提供一个最小成本的供水系统来说是重要的。环状管网最常见的两个供水结构是方格状、环状和辐射状；然而，我们不可能找到一个最佳的几何形状而使得成本最低。 一般地，城镇供水系统是单入口环状管系统。如上所说，环状系统有一些通过系统相互连接的管道使得通过这些连接接的管道，可以供水到同一个需水点。与枝状系统不同，在环状系统中，由于需水量在空间和时间上的变化，管道中的水流方向并非不变。 环状管网可为系统提供余量，提高系统应对局部变化的能力，并且保证管道故障时为用户供水。从水质方面来说，环状形状可减少水龄，因此被推广。管道的尺寸和配水系统的设计对减少水龄来说是重要的因素。由于多方向水流模式和系统中流动模式随时间的变化，水不会停留在一个地方，这样减少了水龄。环状配水系统的优缺点如表4.1所述。 优点:1.Minimize loss of services.as main breaks can be isolated due to multidirectional flow to demand points.2.Reliability for fire protection is higher due to redundancy in the system.3.Likely to meet increase in water demand -higher capacity and lower velocities.4.Better residual chlorine due to in line mixing and fewer dead ends. 5.Reduced water age. 在文献中曾记载过，只考虑最低成本设计的环状管网系统会转化成树状似的结构，这一做法导致在最终的设计中失去最初的几何形状。环状保证了系统的可靠性。因此，一个只考虑最低成本为依据的设计打败了在环状管网中所提供的基本功能。有文献记载设计环状管网系统的方法。尽管这个方法也是仅以考虑最低成本为基础，它通过对管网中所有管道最优化规划从而保持了管网的环状结构。
https://www.doczj.com/doc/b117931316.html,/finance/company/consumer.html Consumer finance company The consumer finance division of the SG group of France has become highly active within India. They plan to offer finance for vehicles and two-wheelers to consumers, aiming to provide close to Rs. 400 billion in India in the next few years of its operations. The SG group is also dealing in stock broking, asset management, investment banking, private banking, information technology and business processing. SG group has ventured into the rapidly growing consumer credit market in India, and have plans to construct a headquarters at Kolkata. The AIG Group has been approved by the RBI to set up a non-banking finance company (NBFC). AIG seeks to introduce its consumer finance and asset management businesses in India. AIG Capital India plans to emphasize credit cards, mortgage financing, consumer durable financing and personal loans. Leading Indian and international concerns like the HSBC, Deutsche Bank, Goldman Sachs, Barclays and HDFC Bank are also waiting to be approved by the Reserve Bank of India to initiate similar operations. AIG is presently involved in insurance and financial services in more than one hundred countries. The affiliates of the AIG Group also provide retirement and asset management services all over the world. Many international companies have been looking at NBFC business because of the growing consumer finance market. Unlike foreign banks, there are no strictures on branch openings for the NBFCs. GE Consumer Finance is a section of General Electric. It is responsible for looking after the retail finance operations. GE Consumer Finance also governs the GE Capital Asia. Outside the United States, GE Consumer Finance performs its operations under the GE Money brand. GE Consumer Finance currently offers financial services in more than fifty countries. The company deals in credit cards, personal finance, mortgages and automobile solutions. It has a client base of more than 118 million customers throughout the world
Laminar and Turbulent Flow Observation shows that two entirely different types of fluid flow exist. This was demon- strated by Osborne Reynolds in 1883 through an experiment in which water was discharged from a tank through a glass tube. The rate of flow could be controlled by a valve at the outlet, and a fine filament of dye injected at the entrance to the tube. At low velocities, it was found that the dye filament remained intact throughout the length of the tube, showing that the particles of water moved in parallel lines. This type of flow is known as laminar, viscous or streamline, the particles of fluid moving in an orderly manner and retaining the same relative positions in successive cross- sections. As the velocity in the tube was increased by opening the outlet valve, a point was eventually reached at which the dye filament at first began to oscillate and then broke up so that the colour was diffused over the whole cross-section, showing that the particles of fluid no longer moved in an orderly manner but occupied different relative position in successive cross-sections. This type of flow is known as turbulent and is characterized by continuous small fluctuations in the magnitude and direction of the velocity of the fluid particles, which are accompanied by corresponding small fluctuations of pressure. When the motion of a fluid particle in a stream is disturbed, its inertia
GRA VITY RETAINING?WALL 1. INTRODUCTION Retaining walls are structures used to provide stability for earth or other material where conditions disallow the mass to assume its natural slope, and are commonly used to hold back or support soilbanks,coal or ore piles, and water. Retaining walls are classified, based on the method of achieving stability, into six principal types (Fig.1). The gravity-wall depends upon its weight, as the name implies, for stability. The cantilever wall is a reinforced-concrete wall that utilizes cantilever action to retain the mass behind the wall from assuming a natural slope. Stability of this wall is partially achieved from the weight of soil on the heel portion of the base slab. A counterfort retaining wall is similar to a cantilever retaining wall, except that it is used where the cantilever is long or for very high pressures behind wall and has counterforts, which tie the wall and base together, built at intervals along the wall to reduce the bending moments and sheers. As indicated in Fig.1c, the counterfort is behind the wall and subjected to tensile forces. A buttressed retaining wall is similar to a counterfort wall, except that the bracing is in front of the wall and is in compression instead of tension. Two other types of walls not considered further are crib walls, which are built-up members of pieces of precast concrete, metal, or timber and are supported by anchor pieces embedded in the soil for stability, and semigravity walls, which are walls intermediate between a true gravity and a cantilever wall. (a)(b)(e)
高速视频处理系统中的信号完整性分析 摘要：结合高速DSP图像处理系统讨论了高速数字电路中的信号完整性问题，分析了系统中信号反射、串扰、地弹等现象破坏信号完整性的原因，通过先进IS工具的辅助设计，找出了确保系统信号完整性的具体方法。 关键词：高速电路设计信号完整性 DSP系统 深亚微米工艺在IC设计中的使用使得芯片的集成规模更大、体积越来越小、引脚数越来越多；由于近年来IC工艺的发展，使得其速度越来越高。从而，使得信号完整性问题引起电子设计者广泛关注。 在视频处理系统中，多维并行输入输出信号的频率一般都在百兆赫兹以上，而且对时序的要求也非常严格。本文以DSP图像处理系统为背景，对信号完整性进行准确的理论分析，对信号完整性涉及的典型问题[1]——不确定状态、传输线效应、反射、串扰、地弹等进行深入研究，并且从实际系统入手，利用IS仿真软件寻找有效的途径，解决系统的信号完整性问题。 1 系统简介 为了提高算法效率，实时处理图像信息，本图像处理系统是基于DSP+FPGA结构设计的。系统由SAA7111A视频解码器、TI公司的TMS320C6701 DSP、Altera公司的EPlK50QC208 FPGA、PCI9054 PCI接口控制器以及SBRAM、SDRAM、FIFO、FLASH等构成。FPGA是整个系统的时序控制中心和数据交换的桥梁，而且能够对图像数据实现快速底层处理。DSP是整个系统实时处理高级算法的核心器件。系统结构框图如图1所示。 在整个系统中，PCB电路板的面积仅为15cm×l5cm，系统时钟频率高达167MHz，时钟沿时间为0．6ns。由于系统具有快斜率瞬变和极高的工作频率以及很大的电路密度，使得如何处理高速信号问题成为一个制约设计成功的关键因素。 2 系统中信号完整性问题及解决方案 2．1 信号完整性问题产生机理 信号的完整性是指信号通过物理电路传输后，信号接收端看到的波形与信号发送端发送的波形在容许的误差范围内保持一致，并且空间邻近的传输信号间的相互影响也在容许的范围之内。因此，信号完整性分析的主要目标是保证高速数字信号可靠的传输。实际信号总是存在电压的波动，如图2所示。在A、B两点由于过冲和振铃[2]的存在使信号振幅落入阴影部分的不确定区，可能会导致错误的逻辑电平发生。总线信号传输的情况更加复杂，任何一个信号发生相位上的超前或滞后都可能使总线上数据出错，如图3所示。图中，CLK为时钟信号，D0、D1、D2、D3是数据总线上的信号，系统允许信号最大的建立时间[1]为△t。在正常情况下，D0、D1、D2、D3信号建立时间△t1<△t，在△t时刻之后数据总线的数据已稳定，系统可以从总线上采样到正确的数据，如图3(a)所示。相反，当信号D1、D2、D3受过冲和振铃等信号完整问题干扰时，总线信号就发生
3单元 地下水位的高低可在一年内大幅波动，下降和上升后，在干燥的季节，降水期。因此，为了保证连续供水，井应穿透许多米水位以下。当水从井里抽水，它在水面产生抑郁，大致锥形的形状，称为漏斗。如果抽重，水表不仅可以降低周围的好但还可延伸到大面积。这在美国西部的部分是这样的。在这种情况下，可以说，地下水被“开采”。即使抽人立即停止，它可能需要数百年的地下水得到补充。下面的例子说明了这一点： 例如，在干燥的美国西南部，含水层补给是每年只有1英寸深的水的十分之二点位置。在这些地区，这是不寻常的泵两英尺或更多的水用于灌溉和其他用途的每年。在这个简单的例子，如果整个含水层抽水的速度，每年的开采量将相当于120年和十年的补给，泵将1200年积累的水。在泵送期间新补给可以忽略不计。机械问题和经济因素阻止完全脱水的含水层，但原则上是有效的例子。 短期承压是适用于任何情况，地下水位上升，在一个以上的水平，这是最初遇到的。这样的情况发生，两个条件必须满足：（1）水，必须限制在一个含水层，是倾斜的，一端暴露在表面，在那里可以得到水；和（2）防渗层，上面和下面的含水层，必须防止水逃避，这样一层被窃听，被上面的水的重量产生的压力会使水上升。如果没有摩擦，井里的水会上升到顶部的水位。含水层。 自流系统作为管道，将水从很远的偏远地区的充电放电点。这样水倒在威斯康星州中部年前现在是从地面和社区许多英里远，伊利诺斯。在南达科他州这样的系统已经从西部的黑山带水，向东跨越国家。在不同的尺度上，城市供水系统可能是人为的自流系统的例子。水塔，为抽水，可能是补给区，管道的承压含水层，在家中的自流井的水龙头。 4单元 矿产勘查在世界表明温度在深油、矿产品通常会增加在地表以下深度增加。在这样的情况下增加温度约0.6度，平均每30米。因此，当地下水在深循环，它变得激烈，如果它上升到表面，水是温泉。一些温泉水在美国，特别是在东部，加热这种方式。在美国，绝大多数的温泉发现于西方。这种分布的原因是，大部分温泉的热源是冷却的火成岩，它是在西方，火成活动已经最近。 间歇泉是间歇性的温泉或喷泉，水柱喷射的伟大力量在不同的时间间隔，通常上升30-60米。水流停止后，一列蒸汽冲出，通常以雷鸣般的轰鸣声。这或许是世界上最著名的间歇泉是黄石公园的老忠实喷发，大约每小时一次。间歇泉也在世界的其他地区，包括冰岛和新西兰，在那里长期间歇泉，意为“喷泉”或“井喷”这个词。 间歇泉时，地下水是地下室加热。室底部，水在巨大的压力下，由于上覆水的重量。因此，一个100度以上的温度就会沸腾所需的前。例如，在一个300米的室内水下必须达到一个温度近230度才开。加热使水膨胀，其结果是某些流出的顶部。这减少了压力，和水变成蒸汽，使间歇泉喷发。 从温泉和间歇泉地下水通常包含在解决方案比其他来源的地下水多材料因为热水比冷水更有效的溶解。当水中含有大量溶解的二氧化硅，硅华沉积在春天。石灰石，方解石的一种，是在石灰岩地区温泉特色存款。一些温泉含硫磺。除了使水的味道不好，硫发出难闻的气味。毫无疑问，臭蛋的春天，内华达州，这种情况。 11单元 一种污染物，是任何物质，生物或化学。在一个可识别的过量的有害的其他理想的生物。在这个框架内，过量的重金属如发汞；某些放射性同位素；氮，磷，钠；和其他有用的，甚至是必要的元素，以及某些致病性细菌和病毒污染物。在某些情况下，材料可作为一种污染物，世界人口中的一段特别的虽然它对其他部分不被认为是有害的。例如，在适当的复合氮超标有害于婴儿，但少了很多成年人如果在所有。在这样的方式，过多的钠盐通常不是有害的，但它可以制约医疗原因盐的摄入饮食的某些人。 不同的物理，地质，生物环境与地下水污染与地表水污染相比是显著的。在后者中，流量和氧气和阳光可用液压，随着速度的过程中污染物的稀释和扩散发生，明显不同于地下水，在污染物降解菌的机会通常局限于土壤或几英尺以下。此外，通过何种渠道地下水运动是非常小的和可变的。由此，显而易见的是，移动速度大大降低，除非，也许，在大的解决渠道内石灰石，以及分散和稀释的机会是非常有限的。此外，地下水通常缺乏氧气，这是造成好氧微生物的种类有帮助但这可能提供了一个“幸福之家”厌氧品种。 大多数土壤和岩石物理过滤出固体的能力，包括污染的固体，是公认的。然而，这种能力会随不同的大小，形状，和滤料颗粒的安排，在选定的沙子和其他材料在水过滤厂使用证明。也知道，但也许不那么普遍，是粘土和其他矿物捕获和交换的一些元素和化合物的能力时，他们游离在溶液中的正或负电荷的元素或化合物。这样的交流，随着吸附和沉淀过程中，污染物的捕获是重要的。这些过程有能力定义的单位是可逆的。他们也可以很容易地在设计设施正确的污染问题所依托的地质环境，土壤和岩石忽视治疗；这种疏忽可能造成地下水污染。这是特别重要的在污水土地应用。 很多猜测，争论，研究发生的地下水污染。地下水污染的主要关注的是化学元素，化合物的引入，和微生物，不含水层，可用于饮用水或是自然发生的，不仅因为该含水层的降解也因为在检测的难度，长期居住，和难度和费用含水层恢复。强有力的论点是，任何废物或可能的污染物应允许进入地下水系统的任何部分。这是一个不可能实现的梦想。相反，答案在于更多的了解自然过程处理废弃物的保证时，土壤和岩石是不能够处理，存储，或回收废物，我们可以发展过程使污染物处理，储存，或可回收。 Extracting and distinguishing environmental change information with high resolution form groundwater and sediments of groundwater system has been the major trend of groundwater sciences towards environmental sciences, This is very useful for forecasting environmental change.4从地下水及其沉积物中提取高分辨率的环境变化信息，实现对环境变化的预警功能是地下水科学向环境科学延伸的重要方向。5而随着全球淡水资源紧缺的形势不断恶化，全球环境变化，特别是全球气候变化对地下水资源的影响成为水文地质研究的新课题。5 With fresh water shortage increasingly serious, the research on effect of globle environmental change, especially globle climate change in groundwater resource has become a new area for hydrogeological research. 4depleted in K and SO4 井的出水量与含水层的渗透系数成正比。 Well water yield is proportional to the transmissivity of a aquifer. 1、分布在这个深层碳酸岩含水层中的地下热水的温度是60℃-90℃。 2、Temperature of the thermal groundwater in the deep-seated carbonate aquifer occurring in this area ranges from 60℃ 3、所有观测井水位的季节性波动可以用研究区降水量的季节性变化来解 4、Seasonal fluctuations in water table in observation wells are interpreted by seasonal changes of/in precipitation in study areas.
Lesson 1 I’m not feeling well. Let’s talk （M=Mom, T= Tom） M: What,'s the matter, Tom T: I'm not feeling well, Mom M: Do you have a cold T: Yes, I think so. Could you give me some water, please M: Here you are. T: Thank you, Mom. M: Tom, you must go and see a doctor. T: OK, Mom. M: It's cold outside. You must wear your coat. T: OK, Mom. Could you pass me my coat,please M: Here you are. T: Thank you, Mom M: Tell me your teacher's number. I'll call him and tell him you are sick. T: OK. Here it is. 译文 (M=妈妈,T=汤姆) 妈妈:怎么了,汤姆 汤姆:我感觉不舒服,妈妈。 妈妈:你感冒了吗 汤姆:是的,我想是这样的。您能给我一些水吗 妈妈:给你。 汤姆:谢谢您,妈妈。 妈妈:汤姆,你必须去看医生. 汤姆:好的,妈妈。 妈妈:外面很冷。你必须穿你的外套。 汤姆:好的,妈妈。您能把我的外套递给我吗 妈妈:给你。 汤姆:谢谢您,妈妈。 妈妈:告诉我你老师的电话号码。我将给他打电话告诉他你生病了。
文档简介 一，英语翻译经典文章之英文原稿二，中文翻译：这篇英语文章的最好翻译版本！不是俺说的，是俺老师说哒！！ 英文原稿Brian It seems my only request (“please, let me sleep”) is not clear enough, so I made this simple table that can help you when you’re in doubt. Especially during the night
中文翻译小子： 我只想好好地睡觉，你不明白吗？！所以，我做了这个简表。当你不知道怎么办时，特 别是在晚上的时候，你可以看看它。 具体情况行动指南 1，我正在睡觉禁止进入 2，你不确定我是否睡觉，你想搞清楚管你“鸟”事；禁止进入 3，你嗑了药，想奔向我的床你他妈的滚远点 4，你在youtube上看了一个超赞的视频，禁止进入；在脸书上把链接发给我想让我看看 5，就算第三次世界大战开始了管我屁事，他妈的别进来 6，你和你的基友们想和我“玩玩”抱歉，直男一枚。不要碰我的任何东西，门都别碰 7，你想整理我的房间我谢谢你了！我自己会打扫 8，普京宣布同性婚姻合法化终于等到“它”！还好你没放弃！还是不要来我房里！ 9，我不在家进我房间，想都别想 10，白天，我在家。你敲了门，我说“请进” 你可以进来了 福利放送！！
如果你已经看到了这里，那么说明你应该是英文爱好者哦。 下面有一些非常实用，我精心整理的英文资料，你一定用得到！快去看看吧！ 一，最常用英语翻译政治文体句型总结大全完美版 二，英文合同翻译最常用句型总结专业版 三，英语毕业论文提纲模板优秀完整详细无敌版
土木工程专业英语课文原 文及对照翻译 Newly compiled on November 23, 2020
Civil Engineering Civil engineering, the oldest of the engineering specialties, is the planning, design, construction, and management of the built environment. This environment includes all structures built according to scientific principles, from irrigation and drainage systems to rocket-launching facilities. 土木工程学作为最老的工程技术学科，是指规划，设计，施工及对建筑环境的管理。此处的环境包括建筑符合科学规范的所有结构，从灌溉和排水系统到火箭发射设施。 Civil engineers build roads, bridges, tunnels, dams, harbors, power plants, water and sewage systems, hospitals, schools, mass transit, and other public facilities essential to modern society and large population concentrations. They also build privately owned facilities such as airports, railroads, pipelines, skyscrapers, and other large structures designed for industrial, commercial, or residential use. In addition, civil engineers plan, design, and build complete cities and towns, and more recently have been planning and designing space platforms to house self-contained communities. 土木工程师建造道路，桥梁，管道，大坝，海港，发电厂，给排水系统，医院，学校，公共交通和其他现代社会和大量人口集中地区的基础公共设施。他们也建造私有设施，比如飞机场，铁路，管线，摩天大楼，以及其他设计用作工业，商业和住宅途径的大型结构。此外，土木工程师还规划设计及建造完整的城市和乡镇，并且最近一直在规划设计容纳设施齐全的社区的空间平台。 The word civil derives from the Latin for citizen. In 1782, Englishman John Smeaton used the term to differentiate his nonmilitary engineering work from that of the military engineers who predominated at the time. Since then, the term civil engineering has often been used to refer to engineers who build public facilities, although the field is much broader 土木一词来源于拉丁文词“公民”。在1782年，英国人John Smeaton为了把他的非军事工程工作区别于当时占优势地位的军事工程师的工作而采用的名词。自从那时起，土木工程学被用于提及从事公共设施建设的工程师，尽管其包含的领域更为广阔。 Scope. Because it is so broad, civil engineering is subdivided into a number of technical specialties. Depending on the type of project, the skills of many kinds of civil engineer specialists may be needed. When a project begins, the site is surveyed and mapped by civil engineers who locate utility placement—water, sewer, and power lines. Geotechnical specialists perform soil experiments to determine if the earth can bear the weight of the project. Environmental specialists study the project’s impact on the local area: the potential for air and
南京师范大学泰州学院 英文翻译原文 年级： 2011级学号：12110330 姓名：申佳佳 系部：信息工程学院 专业：通信工程 题目：基于C51的数字测速仪设计与仿真 指导教师：焦蓬蓬 2015 年 4 月 5 日
Linux - Operating system of cybertimes Though for a lot of people , regard Linux as the main operating system to make u p huge work station group, finish special effects of " Titanic " make , already can be re garded as and show talent fully. But for Linux, this only numerous news one of. Rece ntly, the manufacturers concerned have announced that support the news of Linux to i ncrease day by day, users' enthusiasm to Linux runs high unprecedentedly too. Then, Linux only have operating system not free more than on earth on 7 year this piece wh at glamour, get the favors of such numerous important software and hardware manufa cturers as the masses of users and Orac le , Informix , HP , Sybase , Corel , Intel , Net scape , Dell ,etc. , OK? 1.The background of Linux and characteristic Linux is a kind of " free (Free ) software ": What is called free, mean users can o btain the procedure and source code freely , and can use them freely , including revise or copy etc.. It is a result of cybertimes, numerous technical staff finish its research a nd development together through Inte rnet, countless user is it test and except fault , c an add user expansion function that oneself make conveniently to participate in. As th e most outstanding one in free software, Linux has characteristic o f the following: (1)Totally follow POSLX standard, expand the network operating system of sup porting all AT&T and BSD Unix characteristic. Because of inheritting Unix outstandi ng design philosophy , and there are clean , stalwart , high-efficient and steady kernels , their all key codes are finished by Li nus Torvalds and other outstanding programmer s, without any Unix code of AT&T or Berkeley, so Linu x is not Unix, but Linux and Unix are totally compatible. (2)Real many tasks, multi-user's system, the built-in n etwork supports, can be with such seamless links as NetWare , Windows NT , OS/2 , Unix ,etc.. Network in various kinds of Unix it tests to be fastest in comparing and ass ess efficiency. Support such many kinds of files systems as FAT16 , FAT32 , NTFS , E x t2FS , ISO9600 ,etc. at the same time .