氯气处理工艺总结

简要介绍了2种氯气处理工艺:①传统的泡沫筛板塔干燥及纳氏泵输送工艺;②洗涤塔、捕集器、填料塔、泡罩塔相串联及透平机输送工艺。并从工艺流程、工艺特点以及实践运行等方面进行比较,发现后一种氯气处理工艺具有工艺结构简单、操作弹性大等优点。     

A wideband patch antenna with a pair of antisymmetric balun as differentially fed network

A novel singly differentially‐fed microstrip patch antenna (DFMA) is proposed, which is composed of a radiating patch, a differentially‐fed network with a twin antisymmetric miniaturized baluns and a ground plane for unidirectional radiation. In the differentially‐fed network, the signal is coupled to the two feedlines on both sides by the two miniaturized baluns. The radiating patch is excited by the coupling feed sheet located below the radiating patch, and the coupling feed sheet is connected to the upper end of the feedline. The lower end of the feedlines is connected to the ground plane, and there is a slot on the ground of the feeding network. Due to the existence of coupling feed sheet and slot, a second nonradiating resonant is achieved, and a wideband property is obtained. Finally, the prototype of the antenna is fabricated and studied experimentally. Simulated and measured results show that the impedance bandwidth of the antenna is 30.3% (1.71‐2.32 GHz) for S₁₁ < ?10 dB. Besides, a stable symmetric radiation pattern is obtained with gain around 9.6 dB and cross‐polarization less than ?21 dB, which demonstrates the designed antenna has the property of wideband, high gain and low cross polarization.     

PN-assisted digital background calibration of two-step ADC to over 14-bit accuracy

A new non-binary multiplying digital-to-analog converter (MDAC) structure with signal-dependent dithering scaling technique is proposed in this paper. A full digital background calibration algorithm based on pseudo-random dithers injection is used to calibrate the nonlinear errors of MDAC. By measuring sampling capacitor mismatch and op-amp gain errors of the pipelined analog-to-digital converter (ADC) in background, the errors will be greatly reduced by the proposed calibration algorithm. At the same time, the signal-dependent dithering scaling technique provides a swing margin to the injected pseudo-random signal. By using this technique, the errors caused by the capacitor mismatch and op-amp gain errors can be calibrated at the same time. What’s more, this method greatly accelerates the convergence speed. A two-stage 14-bit pipelined ADC is used to simulate and verify the proposed algorithm. The simulation results indicate the effectiveness of the technique, in which the signal-to-noise plus distortion (SNDR) and the spurious-free dynamic range (SFDR) performance of a 14-bit two-step ADC are improved from 49.12 and 56.25 to 85.68 and 102.23 dB with the input frequency being 0.06 * f _s , respectively. The SFDR is more than 98 dB. The SNDR reaches 84 dB in the whole Nyquist bandwidth after calibration. Integral nonlinearity is improved from 80 to 1.5 least significant bits after calibration.     

High-speed serial interface for converter using the JESD204B protocol

In order to reduce the pin count, the cost and size of packaging, and complexity of system design, a high speed serial interface protocol named JESD204B has been proposed by the JEDEC committee. This paper presents a specific implementation scheme of the transceiver controller based on this protocol. The implemented controller of the transceiver with 4 lanes has been verified with the high speed serial transceiver Xilinx FPGA GTH under a data rate of 6.25Gbit/s.     

Rhodafluor-based chromo- and fluorogenic probe for cyanide anion

A rhodafluor-based chromo- and fluorogenic probe for CN⁻ has been designed, synthesized, and characterized. The probe comprises a spectroscopic unit of rhodafluor and a CN⁻-specific trifluoroacetylamino binding unit. The probe itself is colorless and nonfluorescent because of its spirocyclic structure, whereas ring-opening of the corresponding spirolactone induced by CN⁻ gives rise to strong fluorescence emission and also clear color changes. In the system, an excellent selectivity toward the detection of CN⁻ in aqueous solution over a wide range of tested anions was observed; moreover, most of the background anions have not any interference with the detection of CN⁻.     

基于FPGA的多功能阵列信号处理系统设计

为了适应阵列信号处理数据量大、实时性高的特点,文中结合项目需求设计了一种基于FPGA的多功能阵列信号处理系统。通过采用先进的大规模高性能FPGA和多路高精度ADC芯片,可完成对40路中频信号的同步采集和数字下变频处理,并由数字波束合成运算得到36组波束数据。通过设置多种类型的对外接口,可实现与多个外联设备的网络数据交互、串口控制、波束控制及MGT高速数据传输。文中给出了系统的硬件和软件总体架构设计,并详细介绍了芯片选型、外设接口及各软件功能模块的具体实现方法。测试结果表明,本系统满足设计需求,具有较强的阵列信号处理能力以及良好的通用性和可扩展性。     

4-channel-interpolated 14-bit high speed CORDIC DDS IP core

The direct digital frequency synthesizer (DDS) has been widely used because of the advantages of less frequency hopping time and fine frequency discrimination. But the disadvantages of narrowband and poor SFDR performance limit the quality of the DDS output signal. Based on the improved phase to sine-amplitude mapping technology, this paper presents a 4-channel-interpolated 14-bit high speed CORDIC DDS IP core with a 4-stage pipelined phase accumulator. Compared with the traditional CORDIC structure, the sample rate is four times higher, and the complexity and area of the circuit are reduced. The test results indicate that when the sample clock frequency is 1GHz and the frequency resolution is 0.23Hz, the output frequency is 82MHz with a SFDR of 86.7dB. Based on the 0.18μm 1P6M CMOS process, the effective area of the IP core is 1.33mm². The DDS presented in this paper can be used in system chips of the high accuracy wide band radar and communication system as embedded application.     

UWB雷达芯片的研究现状与发展

超宽带(UWB)系统具有高传输速率、低功耗、探测精度高、穿透性强、安全性高等优势,在军事、雷达、生物探测、短距通信及室内室外高精度定位等场景有着广泛的应用.并且随着半导体技术的发展,基于CMOS的UWB雷达芯片成为研究热点.国内外众多学者及商业公司提出各具优势的UWB芯片及系统.该文从UWB系统、UWB芯片架构中关键电...     

A PA/O-NGO/PPS sandwich composite membrane prepared via multi-step interfacial polymerization for desalination

In view of the disadvantages of concentration polarization and trade-off effects in the application of membrane in desalination field, oxide-nano graphene oxide/polyamide (O-NGO/PA) loose intermediate layer and PA ultra-thin dense layer were introduced to fabricate PA/O-NGO/polyphenylene sulfide composite membrane with sandwich structure via multi-step interfacial polymerization (MS-IP) method. The selective permeation mechanism of ultrathin layer produced by different aqueous monomers (PIP and MPD) was studied, the effect of its physicochemical structure on the relief of concentration polarization phenomenon and the breakthrough of trade-off effect was analyzed. The ultra-thin and dense PA layer mainly played the role of interception and shortened the water molecular penetration path. In the retention test of metal salt solution, compared with the rough surface, it was found that the smooth surface was more conducive to the diffusion of intercepted metal ions into the feed solution, thus alleviating the concentration polarization phenomenon.

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