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Envelope tracking power amplifiers (ETPAs) with either analog or digital modulators are described and compared, with emphasis on 5G NR applications. The analog modulator reproduces the envelope amplitude signal with a goal of higher fidelity, while digital envelope modulators produce a discrete stepwise approximation of the envelope signal with a goal of higher efficiency. Analog series-parallel hybrids vs digital power-DACs, tap-changers, and multi-switchers, paired with RF power amplifier such as Class J, E, or F will be reviewed. Linearization schemes for the analog and digital techniques will be shown, with memory effect mitigation and adaptive digital predistortion, including multidimensional linearization for reduced bandwidth envelope tracking.

We report a multiband Envelope-Tracking (ET) Power Amplifier (PA), comprising a very broadband RF-PA stage and a Voltage-Mode class-D (VMCD) buck-converter with 200MHz switching frequency. Both buck-converter and RF-PA were fabricated using a GaN HEMT process. High frequency switching operation of the buck-converter makes it possible to handle broadband signals (20MHz bandwidth). The design of the RF-PA allows operation over a multi-GHz range of carrier frequencies (0.7 to 2.1GHz). The proposed ET-PA achieved DE of 26∼49%, Output Power of 29.2∼33.0dBm and Gain of 11.1∼7.8dB with 28V supply. This is the first report of broadband and multiband ET-PA, fabricated entirely with a GaN HEMT process.

【目的】ホットフラッシュは終末期前立腺がん患者のQOLを損なう難治性な症候である. 男性のホットフラッシュにガバぺンチンが著効した症例を経験したので報告する. 【症例】70歳代, 男性. 前立腺がん(stage D). LH-RHアゴニストを投与され, 投与開始2カ月目よりSTAS-J, 自覚症状共に3/4-4/4程度のほてりが出現し, QOLが著しく損なわれていた. 鎮痛補助薬としてガバぺンチン400mg/日の投与を開始したところ, 投与開始7日目には, ほてりがSTAS-J, 自覚症状共に2/4にまで改善した. 以降, ガバぺンチン増量し, 1,000mgまで増量した投与開始17日目にはSTAS-J, 自覚症状共に0/4にまでほてりは劇的に改善した. 1,200mgまで増量し維持量としたが, 以降, ホットフラッシュは出現せず, QOLが保たれた. 【結論】本症例は, 鎮痛補助薬として使用したガバペンチンによって, 前立腺がんホルモン療法の副作用であるホットフラッシュが著明に改善された. 本症例および文献的考察により, ガバペンチンは終末期前立腺がん患者のQOLを改善する可能性があると考える. Palliat Care Res 2009; 4(2): 334-338

Many white and/or nearly white objects are in our living and working areas, such as documents written on white paper, white curtains, white clothes, and white walls and furniture. The perceived whiteness of these objects is important to the impression of lighting in these areas. To investigate the perceived whiteness in living areas, a series of experiments were conducted using four different fluorescent lamps in three different environmental conditions. It was found that the areas of perceived whiteness in the living areas were larger than the areas of perceived whiteness under achromatic conditions. Based on the results of these results, a perceived whiteness index is proposed for these experimental conditions.

In the Polar Patrol Balloon (PPB) project, two balloons named PPB-8 and -10 were launched in rapid succession to form a cluster of balloons during their flight on January 13, 2003, from Syowa Station, Antarctica. In order to make the two-dimensional images for auroral X-rays and to obtain the energy spectra of auroras with energy range from 30 keV to 778 keV, the same instruments for hard X-rays were installed on PPB-8 and -10, respectively. These detection systems observed several auroral X-ray events during the flight. In particularly on January 25, 2003, strong auroral events were detected at about 0919 UT by PPB-10 and at 0927 UT by PPB-8. The aurora observed by PPB-10 was observed after about 8 min by PPB-8 located a 650 km west of PPB-10. The energy spectra of the bright aurora at 0919 UT and 0927 UT for PPB-10 and -8 is obtained as E0 = (78+-5) keV and (70+-5) keV, respectively.

The effects of correlated color temperature and the chromaticity of light sources on the perception of surface whiteness were investigated. For the experiment, a Munsell N9.25 chip and 11 nearly white chips (V = 9.25, Munsell chroma ≦ 1.0) were selected. The interval scale of the whiteness of these chips was determined from the results of pair comparisons under eight different fluorescent lamps with correlated color temperatures from 2800 to 6700 K. The Munsell 3PB, 10PB, 7P, and N chips gained high scores under 6700 K illumination, whereas the 3PB, 5B, 7BG, and 9G chips scored higher under the 2800 K illumination. The 12 chips were divided into two groups. In one group, the interval scale from the bottom was found to increase as the correlated color temperature increased, whereas in the other group, it decreased with the temperature. The Munsell 3PB/9.25/1.0 chips fell into the latter group but consistently exhibited the highest or at least high-order scores for all the illuminations examined. In those cases in which the correlated color temperature was held constant, the chromaticity of the light source was found to have no significant effect on the whiteness interval scale. A high correlation was identified between the interval scale of the whiteness and the two metrics, the metric chroma of CIELAB, and CIECAM97s chroma C. © 2003 Wiley Periodicals, Inc. Col Res Appl, 28, 96–102, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.10129

We report a digitally-driven switching-mode amplifier using GaN devices in Voltage-Mode Class D operation, for use at 465 MHz (the recently designated frequency for LTE Band 31). The amplifier is fabricated as an integrated circuit including output devices and drivers. The output circuit employs two stacked GaN FETs; a bootstrap-drive configuration is used in order to increase the driver-stage efficiency for the uppermost GaN FET. The GaN VMCD amplifier achieves peak power-added efficiency of 66.6%, and an output power of 3.3W. At 6dB power backoff, power-added efficiency of 36.3% is achieved. These power-added efficiency values are the highest for reported GaN VMCD amplifiers at a commercial wireless frequency.

Before hemodialysis (HD), plasma levels of tissue factor (TF), free-TF pathway inhibitor (TFPI) and thrombo modulin (TM) were significantly higher in patients with HD than in healthy volunteers. Plasma levels of (T-F) TFPI and plasmin plasmin inhibitor complex (PPIC) were significantly higher in patients with HD than in healthy volunteers. During HD, plasma levels of TF and (T-F) TFPI were not significantly increased, but plasma levels of total TFPI and free TFPI at 1 hour after and at the end of HD were significantly increased, compared with levels before start of HD. Plasma level of PPIC 1 hour after start of HD was significantly higher than before start of HD, and plasma levels of thrombin antithrombin com plex (TAT). PPIC. D-dimer. TM, and protein C (PC) at the end of HD were significantly higher than before start of HD. In patients with thrombosis complications, plasma TF levels were significantly higher than in patients without thrombotic com plications during HD. Plasma levels of PC were significantly lower in patients with thrombotic complications than in patients without thrombotic complications. There was no significant difference between both groups during HD in hemostatic pa rameters, with the exception of TF and PC. Hemostatic abnormalities existed in patients with HD; espe cially, increased TF and decreased PC might cause thrombotic complications.

Hemostatic abnormalities were examined in 55 pa tients during maintenance hemodialysis (HD). Before HD, plasma protein C and protein S antigens were almost within the normal range, while plasma thrombin-antithrombin III complex (TAT III) and plasmin-plasmin inhibitor complex (PPIC) levels in HD patients were increased slightly, and plasminogen acti vator inhibitor 1 level was significantly increased, compared to that in normal volunteers. Plasma activated protein C (APC) and protein C inhibitor (PCI) complex and APC α1 antitrypsin (α1AT) complex were not detected in normal volunteers; how ever, plasma APC-PCI complex was increased in 36 of the patients and plasma APC-α1AT complex was increased in 25 patients. Plasma PCI levels in these patients before HD were significantly decreased. Plasma TAT, PPIC, and tissue type plasminogen activator levels were significantly higher before HD than after 1 hour HD and at the end of HD, while the changes in plasma protein C antigen, protein S antigen, PCI antigen, APC-PCI complex, and APC-α1AT complex were not significant after 1 hour of HD or at the end of HD compared to levels before HD. Plasma PCI levels were correlated with APC- PCI complex, suggesting that decreased PCI levels might be caused by the activation of protein C.

A broadband push-pull power amplifier with power added efficiency (PAE) greater than 47% from 500 MHz to 2.5 GHz is reported. The power amplifier comprises two GaN integrated circuits whose outputs are combined with a broadband balun to achieve power up to 20W. Each IC contains two stacked GaN HEMTs and is designed to employ a load impedance of 25Ω without any reactive matching in order to achieve broadband operation. To provide a better input impedance match to 25Ω and to reduce gain variation over frequency, an RC feedback network is used. Measurements, under CW excitation, demonstrated greater than 63% power added efficiency at select frequencies and greater than 47% over the entire bandwidth.

In this paper, we report a DC/DC converter based on GaN HEMT's with a switching frequency of 200 MHz that can be used to generate envelope-modulated power supply voltages for use in envelope tracking power amplifiers. The converter consists of switching circuits using 0.25-um GaN HEMTs, inductor, and low pass filter, and can provide output voltages above 28V. An integrated bootstrap driver of the switching circuits is employed in order to reduce DC power consumption of the driver stage. Generation of envelope power supply voltages for 20 MHz LTE signals was demonstrated using 200 MHz switching rates with efficiency of 73%(including dissipation in final and driver stages). The chip size is 1075×990 um2.

The graphite felt electrode, coated with ca. 3 wt% polyacrylic acid, was modified by successive reactions with hexamethylenediamine (for cross-linking), 4-amino-2,2,6,6-tetramethylpiperydinyl-1-oxyl(4-amino-TEMPO) and diazomethane (for methylation). Properties of the electrode, were compared with a non-crosslinked and non-methylated one, a crosslinked and a non-methylated one, and a crosslinked and incompletely methylated one; the present electrode was stable and oxidized nerol to neral selectively with turnover number > 1560.

In this study, we conducted the experiment to compare the whiteness perception of Finnish and Japanese observers. The rank order of perceived whiteness among seven nearly white Munsell chips (Value is 9.25 or 9.5, Chroma is 0, 0.5 or 1.0) under the fluorescent lamps of correlated color temperatures of 3000K, 5000K, and 6700K was determined. Observing condition employed in the two laboratories was exactly the same as well as the experimental procedure. In 3000K condition, the results of Japanese and Finnish observers agreed with each other quite well, while as the correlated color temperature becomes higher, the results from the two laboratories showed different tendencies. Negative correlation was found between the whiteness rank order and the metric chroma for all of the results.

There are many white objects around us. For example, there are white papers, white clothes, white ceramics etc. Therefore the whiteness perception of white objects plays an important role in the impression of lighting as well as perceived color of colored objects. Whiteness perception of white objects is influenced by color temperature or chromaticity of the light sources more than the colored objects. Ayama et al. has been investigating the relationship between color temperature or chromaticity of the light sources and the whiteness perception of white objects. In this paper an objective method for quantifying whiteness perception is studied. We attempt to investigate the relationship between chroma derived from some recent color appearance models and whiteness perception. Mainly the relationship between chroma derived from CIECAM97s and whiteness perception is discussed. As a result of the investigation, it was made clear that as the chroma becomes lower the whiteness perception becomes higher and that the whiteness perception is equal if chroma is equal even if the hue varies.