CFZ195型柴油机的开发

本文介绍了CFZ195柴油机的设计思路、主要部分的设计方案及结构特点、主要性能指标及试验研究情况。     

改进型CIC抽取滤波器设计与FPGA实现

为了改善级联积分梳状(CIC)滤波器通带不平和阻带衰减不足的缺点,给出一种改进型CIC滤波器.该滤波器在采用COSINE滤波器提高阻带特性的基础上,级联了一个SINE滤波器,补偿了其通带衰减.硬件实现时,采用新的多相分解方法结合非递归结构,不仅大大减少了存储单元数量,还使电路结构更加规则.经仿真和FPGA验证,改进型CIC滤波嚣使用较少硬件,实现了阻带衰减100.3 dB,通带衰减仅为0.000 1 dB.     

1.0 V low voltage CMOS mixer based on voltage control load technique

A CMOS active mixer based on voltage control load technique which can operate at 1.0 V supply voltage was proposed,and its operation principle,noise and linearity analysis were also presented.Contrary to the conventional Gilbert-type mixer which is based on RF current-commutating,the load impedance in this proposed mixer is controlled by the LO signal,and it has only two stacked transistors at each branch which is suitable for low voltage applications.The mixer was designed and fabricated in 0.18 μm CMOS pr...     

少学时化工原理课程设计教学改革实践

针对少学时化工原理课程设计中存在的问题,结合少学时专业背景,通过强化工程实践、建立工程理念、激发学生学习的自主性及能动性、分专业制定设计题目及内容、强化师资队伍建设等五个方面进行了教学改革与实践,体现了少学时课程设计的专业特色,提高了少学时专业学生理论联系实际,分析及解决工程问题的能力。     

应用于subLVDS接口的1.5Gb/s收发器设计

介绍了subLVDS接口的系统结构并给出一种改进的内部收发器实现电路.为了稳定直流工作点,在发送器内部加入与电源电压无关的自偏置电压源和共模负反馈电路;通过轨到轨预放大器,接收器的共模输入电压可以达到电源至地的范围.SMIC0.18μm 1P6M的工艺下,仿真结果表明该系统对随机输入数据的工作速度可以达到1.5Gb/s,工作温度范围为-40～120℃.     

Low power consumption high speed CMOS dual-modulus 15/16 prescaler for optical and wireless communications

Frequency synthesizer is an important part of optical and wireless communication system. Low power comsumption prescaler is one of the most critical unit of frequency synthesizer. For the frequency divider, it must be programmable for channel selection in multi-channel communication systems. A dual-modulus prescaler (DMP) is needed to provide variable division ratios. DMP is considered as a critical power dissipative block since it always operates at full speed. This paper introduces a high speed and low power complementary metal oxide semiconductor (CMOS) 15/16 DMP based on true single-phase-clock (TSPC) and transmission gates (TGs) cell. A conventional TSPC is optimized in terms of devices size, and it is resimulated. The TSPC is used in the synchronous and asynchronous counter. TGs are used in the control logic. The DMP circuit is implemented in 0.18 μm CMOS process. The simulation results are provided. The results show wide operating frequency range from 7.143 MHz to 4.76 GHz and it comsumes 3.625 mW under 1.8 V power supply voltage at 4.76 GHz.     

CFZ195型柴油机的开发

本文介绍了CFZ195柴油机的设计思路、主要部分的设计方案及结构特点、主要性能指标及试验研究情况。     

氯苯连续绝热硝化合成硝基氯苯过程设计

依据氯苯绝热硝化反应合成硝基氯苯工艺过程的特点和中试试验结果,对5万t/a硝基氯苯生产过程中,氯苯连续绝热硝化反应合成硝基氯苯过程进行了设计。该过程主要由SV-5/100型18 m长静态混合硝化反应器、耐腐高压泵、涡轮流量计、氯苯槽、混酸槽等组成。该工艺过程具有反应速率高、过程安全可靠、物料及能量的利用效率高、三废量少、操作费用低、产品质量稳定等优点。     

A low-voltage low-power CMOS voltage reference based on subthreshold MOSFETs

This paper describes a CMOS voltage reference using only resistors and transistors working in weak inversion,without the need for any bipolar transistors.The voltage reference is designed and fabricated by a 0.18μm CMOS process.The experimental results show that the proposed voltage reference has a temperature coefficient of 370 ppm/℃at a 0.8 V supply voltage over the temperature range of-35 to 85℃and a 0.1%variation in supply voltage from 0.8 to 3 V.Furthermore,the supply current is only 1.5μA at 0.8 V supply voltage.     

回流操作条件下植物甾醇与过量乙酸酯化反应动力学

以豆甾醇、β-谷甾醇、菜油甾醇和菜籽甾醇与乙酸的酯化反应为研究体系,测定了回流操作条件下甾醇与过量乙酸的酯化反应动力学,研究了强酸性苯乙烯型阳离子交换树脂作为催化剂对酯化反应速率的影响以及系统中水的含量对反应速率和酯化反应转化率的影响。实验结果表明,豆甾醇、β-谷甾醇、菜油甾醇和菜籽甾醇与乙酸在回流条件下反应动力学方程均为:r=(0.278±0.002)×CSL(mol·L?1?h?1),加入0.5%~5.0%的催化剂量对反应速率常数的影响在5%以内,乙酸中含3.0%~15.0%的水时,反应转化率明显降低。此外还对精制混合甾醇与乙酸反应分离制备甾醇乙酸酯的工艺进行了研究以及对甾醇乙酸酯产物的热力学性质进行了分析测定,为应用化学反应和结晶法结合分离精制单组分植物甾醇提供了一定的理论依据和基础数据。