A 20 dBm Fully-Integrated 60 GHz SiGe Power Amplifier With Automatic Level Control

A + 20 dBm power amplifier (PA) for applications in the 60 GHz industrial scientific medical (ISM) band is presented. The PA is fabricated in a 0.13-mum SiGe BiCMOS process technology and features a fully-integrated on-chip RMS power detector for automatic level control (ALC), built-in self test and voltage standing wave ratio (VSWR) protection. The single-stage push-pull amplifier uses center-tapped microstrips for a highly efficient and compact layout with a core area of 0.075 mm². The PA can deliver up to 20 dBm, which to date, is the highest reported output power at mm-wave frequencies in silicon without the need for power combining. At 60 GHz it achieves a peak power gain of 18 dB, a 1-dB compression (P1dB) of 13.1 dBm, and a peak power-added efficiency (PAE) of 12.7%. The amplifier is programmable through a three-wire serial digital interface enabeling an adaptive bias control from a 4-V supply.     

Realization of Fully Controllable Negative Inductance with Single Operational Transresistance Amplifier

A grounded negative inductance emulator is proposed with full independent control on both the inductance value and the condition. It uses a single operational transresistance amplifier (OTRA), a capacitor, and five resistors, two of which are for independent control. Experimental results, which confirm the theoretical analysis, are presented.     

Is there any interaction of resistin and adiponectin levels with protein‐energy wasting among patients with chronic kidney disease

The aim of this study was to evaluate the effects of adipocytokines including adiponectin, leptin, resistin, neuropeptide Y and ghrelin in chronic kidney disease (CKD) patients on appearance of protein‐energy wasting (PEW). One hundred fifty patients with mean age of 45.4 ± 15.9 years, without active infections or chronic inflammatory conditions were recruited into the study. Study groups were control group (consisting of 30 healthy volunteers with normal kidney functions), hemodialysis group, predialysis group, peritoneal dialysis group and kidney transplant group. Fasting morning serum leptin, ghrelin, acylated ghrelin, neuropeptide Y, adiponectin, resistin levels of all of the groups were measured. Anthropometric and nutritional assessments of all patients were obtained. Diagnosis of PEW was made according to definition recommended by the International Society of Renal Nutrition and Metabolism. Presence of PEW in hemodialysis (23.3%) and peritoneal dialysis (26.7%) groups were significantly higher than those of predialysis (3.3%), and transplantation (0%) groups. Adiponectin and resistin levels in predialysis, peritoneal dialysis and hemodialysis patients were significantly higher than control group (p: 0.0001). This study had given significant positive correlations between presence of PEW and serum resistin (r: 0.267, p: 0.001), and serum adiponectin levels (r: 0.349, p: 0.0001). There were no relationship between presence of PEW and ghrelin, acylated‐ghrelin, neuropeptide Y, and leptin levels of the groups. CKD patients except transplant patients had higher adiponectin and resistin levels than control group. PEW was found to be linearly correlated with resistin and adiponectin. High serum resistin and adiponectin levels might have a role in development of PEW among dialysis patients.     

Relationships between acute toxicities of para nitrophenol (p-NP) and nitrobenzene (NB) to Daphnia magna and Photobacterium phosphoreum: physicochemical properties and metabolites under anaerobic/aerobic sequentials

In this study, the acute toxicities of nitrobenzene (NB) and para nitrophenol (p-NP) were investigated in a high rate sequential anaerobic migrating blanket (AMBR)/aerobic completely stirred tank reactor (CSTR) using Microtox and Daphnia magna tests. After sequential anaerobic and aerobic treatments, the inhibitions in the Microtox bacteria decreased from an initial 78.10-48.20% and 4.00%, respectively, in wastewater containing 40.00 mg/L p-NP. The inhibitions of the influent wastewater containing 60.00 mg/L NB decreased from 72.10% to 45.30% and to 4.00% after anaerobic and aerobic treatment, respectively. The acute toxicity removals were 94% and 93% in the effluent of the whole sequential system, for p-NP and NB, respectively. The acute toxicity in the influent was dependent on the parent NB and p-NP concentrations and ons their physicochemical properties such as hydrophobicity, octanol/water partition coefficient and vapour density for both Microtox bacteria and Daphnia magna while the toxicity in the effluent of the anaerobic reactor was strongly dependent on the metabolites of p-NP (p-amino phenol, phenol, NH(4)-N) and NB (aniline) for Microtox test. This effluent was not toxic to Daphnia magna.     

Experimental investigation and analysis of a new photoelectrochemical reactor for hydrogen production

In this research paper, an experimental investigation of photoactive material titanium dioxide (TiO₂) coated on 180 cm² 316 stainless steel anode is undertaken to study the photoresponse on photoelectrochemical (PEC) hydrogen production. The TiO₂ nanoparticles are first prepared via sol-gel method. A large surface 316 stainless steel anode is coated with TiO₂ nanoparticles by a dip coating apparatus at a withdraw rate of 2.5 mm/s. The nanoparticles are carried on the stainless steel substrate by two-step annealing procedure. The potentiostatic studies confirm the photoactivity of TiO₂ nanoparticles in a photoelectrochemical reactor when exposed to solar ultraviolet (UV) light. The photon to current efficiency measurements carried out on the PEC reactor with TiO₂ coated large surface stainless steel as photoanode demonstrate a significant increase of photoresponse in UV light compared to the uncoated stainless steel prepared under similar conditions. Upon illumination at a power density of 600 W/m², the hydrogen production is observed in TiO₂ coated stainless steel substrate at a measured rate of 51 ml/h while no illumination conditions show a production rate of 42 ml/h. In comparative assessments, the TiO₂ coated substrate shows an increase in photocurrent of 10 mA with an energy efficiency of 1.32% and exergy efficiency of 3.42% at an applied potential of 1.6 V. The present results show a great potential for titanium nanoparticles semiconductor metal oxide in photoelectrochemical hydrogen production application.     

Signal level performance variation of radio frequency identification tags used in cow body

Ruminant diseases are strictly connected to pH and temperature values of the rumen. Therefore, the attenuation to dynamic measurement and tracking of both pH and temperature values through animal rumen has grown rapidly for decades. Reading performance of RFID tags depends on signal quality and signal level, and this can be understood by means of wave attenuation through tissue. In this article, attenuation through cow body is investigated for improving reading performance and battery life. Number of receiving antennas will be used in the system, their location and heights are critical for this aim. Signals from different points of animals' body are measured and compared with the signals spread just out of RFID tags. Equivalent dielectric constants of tissue between RFID tag and receiving antenna is modeled by using literature data, and finally simulation and analytical results are verified by measurement results. Measured value of attenuation through the cow body is varying between 25 dB and 87 dB for RFID tags operating at 434 MHz. Within the 30 m radius, the strongest signal is obtained at 50 cm height and taken from the left side of the animal body, which is offered as optimum communication position.     

Pros and cons of the new financial support policy for Turkish researchers

Scientometrics - In 2015, a new ex-post incentive policy was introduced in Turkey to increase the academic productivity of researchers. This convergent parallel design study aims to find an answer...