PPS导向系统在TBM中的应用

TBM的PPS定位、导向系统,可为TBM确切位置和掘进方向定位,为操作手提供TBM偏离轴线的信息。根据PPS系统的定位原理,掌握PPS在TBM中应用的程序,了解TBM在掘进过程中的偏差因素,采取对其纠偏的措施,可保证TBM严格按设计坐标方位掘进。     

浅谈辽宁省大伙房水库输水工程施工进度控制

大型水利工程的进度控制一直是研究的热点和难点,结合大伙房水库输水工程的实际情况和特点,提出了以四级动态网络计划对施工阶段工程进度进行控制,保证了工程施工的顺利进行。     

A multi-mode multi-band RF receiver front-end for a TD-SCDMA/LTE/LTE-advanced in 0.18-μm CMOS process

正A fully integrated multi-mode multi-band directed-conversion radio frequency(RF) receiver front-end for a TD-SCDMA/LTE/LTE-advanced is presented.The front-end employs direct-conversion design,and consists of two differential tunable low noise amplifiers(LNA),a quadrature mixer,and two intermediate frequency(IF) amplifiers.The two independent tunable LNAs are used to cover all the four frequency bands,achieving sufficient low noise and high gain performance with low power consumption.Switched capacitor arrays perform a resonant frequency point calibration for the LNAs.The two LNAs are combined at the driver stage of the mixer,which employs a folded double balanced Gilbert structure,and utilizes PMOS transistors as local oscillator(LO) switches to reduce flicker noise.The front-end has three gain modes to obtain a higher dynamic range.Frequency band selection and mode of configuration is realized by an on-chip serial peripheral interface(SPI) module.The frontend is fabricated in a TSMC 0.18-μm RF CMOS process and occupies an area of 1.3 mm~2.The measured doublesideband (DSB) noise figure is below 3.5 dB and the conversion gain is over 43 dB at all of the frequency bands. The total current consumption is 31 mA from a 1.8-V supply.     

A RF receiver frontend for SC-UWB in a 0.18-μm CMOS process

正A radio frequency(RF) receiver frontend for single-carrier ultra-wideband(SC-UWB) is presented. The front end employs direct-conversion architecture,and consists of a differential low noise amplifier(LNA),a quadrature mixer,and two intermediate frequency(IF) amplifiers.The proposed LNA employs source inductively degenerated topology.First,the expression of input impedance matching bandwidth in terms of gate-source capacitance, resonant frequency and target S_(11) is given.Then,a noise figure optimization strategy under gain and power constraints is proposed,with consideration of the integrated gate inductor,the bond-wire inductance,and its variation.The LNA utilizes two stages with different resonant frequencies to acquire flat gain over the 7.1-8.1 GHz frequency band,and has two gain modes to obtain a higher receiver dynamic range.The mixer uses a double balanced Gilbert structure.The front end is fabricated in a TSMC 0.18-/im RF CMOS process and occupies an area of 1.43 mm~2.In high and low gain modes,the measured maximum conversion gain are 42 dB and 22 dB,input 1 dB compression points are -40 dBm and -20 dBm,and S_(11) is better than -18 dB and -14.5 dB.The 3 dB IF bandwidth is more than 500 MHz.The double sideband noise figure is 4.7 dB in high gain mode.The total power consumption is 65 mW from a 1.8 V supply.     

浅谈TBM掘进中的地质灾害及防治措施

开敞式TBM适合于相对较硬岩石掘进,但在软弱围岩的掘进过程中易出现掌子面与临空面围岩失稳、涌水,造成开挖洞室变形、坍塌、掉块等地质灾害。结合辽宁省大伙房水库输水工程TBM2标段施工,从地质和设备特点两方面分析地质灾害产生的原因,并简要论述有关灾害的防治措施。     

UPS的使用和维护

论述了UPS的使用和维护方法,确保UPS能够更好地工作,延长UPS和电池组的使用寿命,保证企事业供电的安全。     

一种用于电抗式有载分接开关电抗器的电感计算

介绍了一种用于电抗式有载分接开关的电抗器的特点及该种电抗器的设计要点。     

CT-SIM的一种新型激光灯定位装置的设计研究

设计了一款新型的CT-SIM三维激光灯定位装置,通过精确的运动设计和高效控制电路设计,保证等中心点的标定精度达到0.1mm。整个装置具有结构简单、响应迅速、定位准确的优点。     

一种移动电视直放站回波抵消的实现方法

回波(回声)抵消是数字直放站的一项关键技术,利用重发信号实现了基于自适应算法的回波信道估计以及回波抵消。仿真实验证明效果较好,并可满足数字直放站的实时性。     

再谈分数匝补偿的几个问题

对二次导线并绕实现分数匝补偿可能造成的负补偿和相位差补偿作出了说明。