一种平衡设计压控振荡器和自动频率校准的快速锁定宽带频率综合器

A wideband fractional-N frequency synthesizer is implemented in a 65 nm CMOS process.It employs a wideband LC voltage-controlled oscillator(VCO) with optimized VCO gain(KVCO/and a sub-band step to improve automatic frequency calibration(AFC) efficiency at negligible expense of phase noise performance.An agile AFC is realized by direct mapping based on the division ratio,and optional redundant counting and comparing calibration is introduced accommodating PVT variations,which samples the reference clock using the prescaled VCO output as a discriminating clock.A charge pump with switched charging current is adopted to compensate for the loop bandwidth variation.Measurement results show this directly-mapped AFC locates the target sub-band in 100 ns and only needs 1.2 s for redundant calibration.The frequency synthesizer spans a frequency range from 0.62 to 1.52 GHz,with phase noise of-86 dBc/Hz at 10 kHz offset and-122 dBc/Hz at 1 MHz offset while consuming 9.76 mA from a 1.2 V supply.     

稀土元素对活性污泥影响的初步研究

初步研究了稀土元素镧（Ｌａ）、铈（Ｃｅ）、镨（Ｐｒ）、钕（Ｎｄ）及其混合物对活性污泥生长的影响。结果表明，５０ｍｇ／Ｌ浓度以上的稀土元素对活性污泥生长有明显的影响，表观变色上浮；显微可见菌胶团疏松分散，原生动物个体游离。     

火电厂低温气候生水预处理的影响分析及对策

对净水站的运行管理、水质分析、技术研究、设备及系统改造等是提高机组运行可靠和经济运行的重要组成部分。     

超高功率石墨电极用针状焦评价方法探析

针状焦是制造高功率和超高功率电极的优质材料,用针状焦制成的石墨电极具有耐热冲击性能强、机械强度高、氧化性能好、电极消耗低及允许电流密度大等优点,针状焦根据使用的原料可分为石油系和煤系两类。以石油重油为原料生产的针状焦为油系,以煤焦油沥青及其馏分为原料生产的针状焦为煤系。两种针状焦生产工艺不完全相同,但用途基本相同。石油系以美国为代表,煤系则以日本为代表。     

Up-Regulation of mRNA Ventricular PRNP Prion Protein Gene Expression in Air Pollution Highly Exposed Young Urbanites: Endoplasmic Reticulum Stress,Glucose Regulated Protein 78, and Nanosized Particles

Mexico City Metropolitan Area children and young adults exposed to high concentrations of air pollutants including fine and ultrafine particulate matter (PM) vs. clean air controls, exhibit myocardial inflammation and inflammasome activation with a differential right and left ventricular expression of key inflammatory genes and inflammasomes. We investigated the mRNA expression levels of the prion protein gene PRNP, which plays an important role in the protection against oxidative stress and metal toxicity, and the glucose regulated protein 78, a key protein in endoplasmic reticulum (ER) stress signaling, in ventricular autopsy samples from 30 children and young adults age 19.97 ± 6.8 years with a lifetime of low (n:4) vs. high (n:26) air pollution exposures. Light microscopy and transmission electron microscopy studies were carried out in human ventricles, and electron microscopy studies were also done in 5 young, highly exposed Mexico City dogs. There was significant left ventricular PRNP and bi-ventricular GRP78 mRNA up-regulation in Mexico City young urbanites vs. controls. PRNP up-regulation in the left ventricle was significantly different from the right, p < 0.0001, and there was a strong left ventricular PRNP and GRP78 correlation (p = 0.0005). Marked abnormalities in capillary endothelial cells, numerous nanosized particles in myocardial ER and in abnormal mitochondria characterized the highly exposed ventricles. Early and sustained cardiac ER stress could result in detrimental irreversible consequences in urban children, and while highly complex systems maintain myocardial homeostasis, failure to compensate for chronic myocardial inflammation, oxidative and ER stress, and particles damaging myocardial organelles may prime the development of pathophysiological cardiovascular states in young urbanites. Nanosized PM could play a key cardiac myocyte toxicity role.     

Study on cross-linking agent of a novel one-component API adhesive

The high reactivity and toxicity of isocyanates do not allow their storage and use in one-component system aqueous polymer isocyanate adhesives. Blocked isocyanates are a solution to protect the isocyanate groups by blocking with suitable blocking agent. In order to obtain eco-friendly systems and eliminate the effect of the organic solvents on environment, the blocked isocyanates can be dispersed in water by using external emulsifier by incorporating hydrophilic groups into the backbone. In this work, a series of waterborne blocked polyisocyanate dispersions were prepared by anionic modified process, using polyaryl polyisocyanate (PAPI), 2,4,6-trichlorophenol (TCP), and dimethylol propionic acid. Particle sizes were measured and compared by laser particle sizer and scanning electron microscopy. The structures of aqueous dispersions were characterized by FTIR, ¹H NMR, and ¹³C NMR, and results confirmed that the –NCO groups are effectively blocked by –OH groups. Thermal property was investigated using differential scanning calorimetry; then, kinetic parameters, ΔE, and n were deduced. It was found that the deblocking temperature of aqueous dispersion is about 55?°C. Hydrophilicity was characterized by measuring the water contact angles. The experimental results showed that the contact angle of solvent-borne solution is 68.6°, while that of aqueous dispersion is only 25.2°, which indicated that the hydrophilicity of waterborne TCP-blocked PAPI increases for the introduced hydrophilic group compared with solvent-borne TCP-blocked PAPI. The compressive shear strength was tested to evaluate wood bonding performance of the adhesive.     

电动汽车充电桩检定过程中的几点经验

本文针对开展充电桩检定工作中所遇到的问题,结合检定规程,对实施充电桩检定时的一些注意事项进行了分析和归纳,并对常见不合格项目进行了阐述。     

High temperature and force measurements using a type II cascaded regenerated fiber Bragg grating (RFBG)

Abstract

A Type II-IR (infrared) grating cascaded with a regenerated fiber Bragg grating (RFBG) is described for force measurements at high temperature. The sensor was fabricated by fusion splicing a Type II grating with a Type I seed grating that was subjected to isothermal annealing in order to obtain the RFBG. Due to the different responses to temperature and force, these parameters were determined by measuring the reflection peak of the Type II grating and RFBG. The experimental results indicate that the sensor may be used for simultaneous measurement of temperature and force from 250?°C to 500?°C and 0.003?N to 0.797?N.     

A study on the design of error-free spur slice cutter

A design method of error-free spur slice cutter is proposed according to urgent demand for the slice cutter in actual production. The structure of the rake face is determined according to technological realization of the design, manufacturing, and tool grinding. On that basis, the mathematical model of the rake face is built. Taking the error-free design as the goal, the mathematical model of major flank face is established based on the principle of the gear slicing. The mathematical models of designing angle and working angle are constructed by the equivalent methodology, spatial geometrical theory, and conjugation theory of space surface. The validity of the above study results is verified by using a calculation example. The design method lays a theory foundation for the study of cutter parameter optimization, tool life, and other aspects.     

粗调和细调相结合的标准CMOS低噪声环形压控振荡器

本文提出了一种基于65nm CMOS标准工艺、采用粗调和细调相结合的低噪声环形压控振荡器。论文分析了环形振荡器中的直接频率调制机理,并采用开关电容阵列来减小环形压控振荡器的增益从而抑制直接频率调制效应。开关电容采用电容密度较高的二维叠层MOM电容使该压控振荡器与标准的CMOS工艺兼容。所设计压控振荡器的频率范围为480MHz～1100MHz,调谐范围为78%,测试得到输出频率为495MHz时的相位噪声为-120dBc/Hz@1MHz。该压控振荡器在1.2V的偏压下的功耗为3.84mW,相应的优值(FOM)为-169dBc/Hz。