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1.
A 90-nm silicon-on-insulator (SOI) CMOS system on-chip integrates high-performance FETs with 243-GHz F/sub t/, 208-GHz F/sub max/, 1.45-mS//spl mu/m gm, and sub 1.1-dB NFmin up to 26 GHz. Inductor Q of 20, VNCAP of 1.8-fF//spl mu/m/sup 2/, varactor with a tuning range as high as 25:1, and a low-loss microstrip. Transmission lines were successfully integrated without extra masks and processing steps. SOI and its low parasitic junction capacitance enables this high level of performance and will expand the use of CMOS for millimeter-wave applications.  相似文献   
2.
This paper presents five-stage and seven-stage traveling-wave amplifiers (TWA) in a 0.12-/spl mu/m SOI CMOS technology. The five-stage TWA has a 4-91-GHz bandpass frequency with a gain of 5 dB. The seven-stage TWA has a 5-86-GHz bandpass frequency with a gain of 9 dB. The seven-stage TWA has a measured 18-GHz noise figure, output 1-dB compression point, and output third-order intercept point of 5.5 dB, 10 dBm, and 15.5 dBm, respectively. The power consumption is 90 and 130 mW for the five-stage and seven-stage TWA, respectively, at a voltage power supply of 2.6 V. The chips occupy an area of less than 0.82 and 1 mm for the five-stage and seven-stage TWA, respectively.  相似文献   
3.
Bark and wood samples were taken from the same individuals of Scots pine (Pinus sylvestris L.) from a polluted area close to a Cu-Ni smelter in Harjavalta and from some relatively unpolluted areas in western Finland. The samples were analysed by thick-target particle induced X-ray emission (PIXE) after preconcentration by dry ashing at 550 degrees C. The elemental contents of pine bark and wood were compared to study the impact of heavy metal pollution on pine trees. By comparison of the elemental contents in ashes of bark and wood, a normalisation was obtained. For the relatively clean areas, the ratios of the concentration in bark ash to the concentration in wood ash for different elements were close to 1. This means that the ashes of Scots Pine wood and bark have quite similar elemental composition. For the samples from the polluted area the mean concentration ratios for some heavy metals were elevated (13-28), reflecting the effect of direct atmospheric contamination. The metal contents in the ashes of pine bark and wood were also compared to recommendations for ashes to be recycled back to the forest environment. Bark from areas close to emission sources of heavy metal pollution should be considered with caution if aiming at recycling the ash. Burning of bark fuel of pine grown within 6 km of the Cu-Ni smelter is shown to generate ashes with high levels of Cu, Ni as well as Cd, As and Pb.  相似文献   
4.
The design of a low-voltage 40-GHz complementary voltage-controlled oscillator (VCO) with 15% frequency tuning range fabricated in 0.13-/spl mu/m partially depleted silicon-on-insulator (SOI) CMOS technology is reported. Technological advantages of SOI over bulk CMOS are demonstrated, and the accumulation MOS (AMOS) varactor limitations on frequency tuning range are addressed. At 1.5-V supply, the VCO core and each output buffer consumes 11.25 mW and 3 mW of power, respectively. The measured phase noise at 40-GHz is -109.73 dBc/Hz at 4-MHz offset from the carrier, and the output power is -8 dBm. VCO performance using high resistivity substrate (/spl sim/300-/spl Omega//spl middot/cm) has the same frequency tuning range but 2 dB better phase noise compared with using low resistivity substrate (10 /spl Omega//spl middot/cm). The VCO occupies a chip area of only 100 /spl mu/m by 100 /spl mu/m (excluding pads).  相似文献   
5.
Chromium, copper and arsenic (CCA) have for decades been used for wood preservation. Of these elements especially arsenic is very toxic. As CCA impregnated wood is still today used for many construction purposes, a monitoring of these metal ions is of great environmental importance. Thick-target PIXE is a powerful method for the determination of trace metals in wood. The TTPIXE method enabled study of variations of the elemental concentrations in lumber treated with CCA impregnation solution. Distribution patterns were obtained for both naturally occurring elements and elements introduced in the treatment process. During the impregnation process a desorption of e.g. alkali metal ions takes place from the wood. The sensitivity of the method is improved by dry ashing of the samples prior to PIXE analysis. The TTPIXE method was calibrated and validated using international certified reference materials (CRM) based on wood material.  相似文献   
6.
Overlap formed at the back and front end in slab ingot rolling is studied theoretically and experimentally. The phenomena are analysed by means of plane strain upper bound solutions for a rigid perfectly plastic material. According to theory the crop loss volume at the front end should be larger than that at the back end. It is concluded that large roll diameters should be used in order to minimize the crop loss. For heavy reductions and large roll diameters the dependence of reduction on the crop loss at the back end is small. The dependence of roll radius is found to be more pronounced for the front than for the back end especially when heavy reductions and small roll radii are concerned.Theory is in good agreement with experiments carried out with plasticine as the model material.  相似文献   
7.
Helicobacter pylori is a human pathogen that infects over 50% of the population worldwide. It is the most important etiologic agent of gastroduodenal ulcers and malignancies. Helicobacter pylori urease enzyme is considered the main factor for the organism's colonization in the gastroduodenal mucosa. Hens immunized with the purified urease produce a highly specific anti-H. pylori urease immunoglobulin (IgY-urease) in their egg yolks. Immunoglobulin Y-urease was stable at 60 to 65 degrees C for 30 min and at pH 4.0 for 7 h. Its activity was lost at 80 degrees C for 20 min and at pH 2 for 4 h. Specially designed functional drinking yogurt containing Lactobacillus acidophilus and Bifidobacterium spp. with 1% egg yolk IgY-urease was produced commercially. Immunoglobulin Y-urease activity showed stability in the product up to 7 d, and then decreased to 85% after 3 wk of storage. A clinical study was conducted to determine the effectiveness of IgY-urease yogurt to suppress infection in humans. Forty-two volunteers who tested positive for H. pylori using a 13C-urea breath test were recruited. A total of 450 mL of IgY-urease (test group) or IgY-urease-free yogurt (control group) was consumed in 150-mL portions 3 times daily for 4 wk. Volunteers were tested after 2 and 4 wk; urea breath test values significantly decreased in the test group compared with the control group. The results indicate that suppression of H. pylori infection in humans could be achieved by consumption of drinking yogurt fortified with IgY-urease.  相似文献   
8.
The textile and apparel industry is the gate of choice for most developing countries in their quest to step into industrialization. The ease of entry into this field and the abnormally high wages in developed countries have created favorable conditions for the manufacturing and the exportation of textile and apparel derived products. At the same time, this unique situation has effected a cutthroat competition among the many actors while fueling an intense protectionism in many developed countries where the export markets are found. However, paradoxically, it is the U.S. trade policies that have been the common factor in the flourishing of the textile and apparel industry in many countries and regions around the world. From Asia, this generous openness has in time reached the Caribbean region and finally Sub-Saharan Africa. The evolution of this fluid industry in developing countries is examined within the boundaries of the textile and apparel managed trade agreements. It is argued that successes in this field must come from the combined efforts of the local government's industrial and trade policies, the entrepreneurial prowess of the private sector and the flexibility and the work ethic of the labor force. From the SE Asia NICs, to the Caribbean states and the Sub-Saharan African region, the synergy created by the U.S. trade policies and the local capabilities is shown to be the major ingredient for the development of the textile and apparel sector in scores of developing countries.  相似文献   
9.
To evaluate the two hypotheses of locally elevated exposure of persistent organic pollutants (POPs) in ice-associated microenvironments and ice as a key carrier for long-range transport of POPs to the Arctic marginal ice zone (MIZ), dissolved and particulate polychlorinated biphenyls (PCBs) were analyzed in ice, snow, ice-interstitial water (IIW), seawater in the melt layer underlying the ice, and in ice-rafted sediment (IRS) from the Barents Sea MIZ to the high Arctic in the summer of 2001. Ultra-clean sampling equipment and protocols were specially developed for this expedition, including construction of a permanent clean room facility and a stainless steel seawater intake system on the I/B ODEN as well as two mobile 370 l ice-melting systems. Similar concentrations were found in several ice-associated compartments. For instance, the concentration of one of the most abundant congeners, PCB 52, was typically on the order of 0.1-0.3 pg l(-1) in the dissolved (melted) phase of the ice, snow, IIW, and underlying seawater while its particulate organic-carbon (POC) normalized concentrations were around 1-3 ng gPOC(-1) in the ice, snow, IIW, and IRS. The solid-water distribution of PCBs in ice was well correlated with and predictable from K(ow) (ice log K(oc)-log K(ow) regressions: p<0.05, r2=0.78-0.98, n=9), indicating near-equilibrium partitioning of PCBs within each local ice system. These results do generally not evidence the existence of physical microenvironments with locally elevated POP exposures. However, there were some indications that the ice-associated system had harbored local environments with higher exposure levels earlier/before the melting/vegetative season, as a few samples had PCB concentrations elevated by factors of 5-10 relative to the typical values, and the elevated levels were predominantly found at the station where melting had putatively progressed the least. The very low PCB concentrations and absence of any significant concentration gradients, both in-between different matrices and over the Eurasian Arctic basin scale, suggest that ice is not an important long-range transport purveyor of POPs to the Arctic MIZ ecosystem.  相似文献   
10.
In this paper, a 1-V 3.8 - 5.7-GHz wide-band voltage-controlled oscillator (VCO) in a 0.13-/spl mu/m silicon-on-insulator (SOI) CMOS process is presented. This VCO features differentially tuned accumulation MOS varactors that: 1) provide 40% frequency tuning when biased between 0 - 1 V and 2) diminish the adverse effect of high varactor sensitivity through rejection of common-mode noise. This paper shows that, for differential LC VCOs, all low-frequency noise such as flicker noise can be considered to be common-mode noise, and differentially tuned varactors can be used to suppress common-mode noise from being upconverted to the carrier frequency. The noise rejection mechanism is explained, and the technological advantages of SOI over bulk CMOS in this regard is discussed. At 1-MHz offset, the measured phase noise is -121.67 dBc/Hz at 3.8 GHz, and -111.67 dBc/Hz at 5.7 GHz. The power dissipation is between 2.3 - 2.7-mW, depending on the center frequency, and the buffered output power is -9 dBm. Due to the noise rejection, the VCO is able to operate at very low voltage and low power. At a supply voltage of 0.75 V, the VCO only dissipates 0.8 mW at 5.5 GHz.  相似文献   
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