GaInNas/GaAs QW Based Structures to Compensate Parasitic Effect of Quantum-Confined Stark Effect in Photodetector Applications

The inhomogeneities of multicomponent semiconductor alloys, as well as phase segregation, can be utilized for enhancement of photodetector absorption properties and thus its efficiency. In this paper, the influence of external electric field on the probability of light absorption in the GaInNAs quantum well is discussed. Both phenomenon: indium and nitrogen composition gradient as well as step-like quantum well are applied to design the QW with compensation of the Quantum-Confined Stark Effect (QCSE) Parasitic effect of QCSE results from decrease of the wave functions overlapping in the QWs placed in reverse biased junction, which finally decrease the efficiency of the photodetector

AP-MOVPE Technology and Characterization of InGaAsN p-i-n Subcell for InGaAsN/GaAs Tandem Solar Cell

Tandem (two p-n junctions connected by tunnel junction) and multijunction solar cells (MJSCs) based on AIIIBV semiconductor compounds and alloys are the most effective photovoltaic devices. Record efficiency of the MJSCs exceeds 44% under concentrated sunlight. Individual subcells connected in series by tunnel junctions are crucial components of these devices. In this paper we present atmospheric pressure metal organic vapour phase epitaxy (AP-MOVPE) of InGaAsN based subcell for InGaAsN/GaAs tandem solar cell. The parameters of epitaxial structure (optical and electrical), fabrication process of the test solar cell devices and current-voltage (J-V) characteristics are presented and discussed

Rak kory nadnerczy w przedoperacyjnych badaniach obrazowych

Background: Decisions concerning surgical treatment of patients with adrenocortical tumor without hormonal hyperactivity are based on tumor size exceeding 3-6 cm and morphological features of malignancy. The aim of the study was to analyze results of diagnostic imaging in patients with adrenocortical carcinoma (ACC). Material/Methods: Results of diagnostic imaging of 8 patients in whom postoperative pathological examination revealed ACC were analyzed. There were 3 women and 5 men in the analyzed group, with an age range of 32 to 75 years. Imaging was based on US and CT examination supported by MRI in 2 patients. The obtained results were compared with a group of 10 patients with adrenocortical adenoma (ACA). Results are presented as median values and 95% CI. Results: CT results of patients with ACC showed local spread into surrounding fat tissue in 87.5%, adjacent organ invasion in 75%, local lymph node enlargement in 75%, irregular tumor margins in 88%, and heterogeneous structure of all tumors. In patients with ACA, tumor heterogeneity was observed in 40% and local lymph node enlargement in 10%. ACC tumors were significantly larger than ACA ones [77 (66-97) vs. 31 (24-48) mm, respectively, p=0.0002] and more dense [60 (34-85) vs. 16 (10-26) HU, respectively, p=0.0007]. In arterial phase, enhancement of ACC tumors tended to be stronger compared with ACA [81 (29-162) vs. 55 (33-76), p=0.09]. On the basis of CT results, 1 patient was classified as stage II according to Mac Farlane, 6 as stage III, and 1 as stage IV. Intraoperative examination down-staged 2 patients from stage III to stage II. Conclusions: Computed tomography is a method that allows distinguishing adrenocortical adenoma from carcinoma as well as to determine the stage of adrenocortical carcinoma

The High-Acceptance Dielectron Spectrometer HADES

HADES is a versatile magnetic spectrometer aimed at studying dielectron production in pion, proton and heavy-ion induced collisions. Its main features include a ring imaging gas Cherenkov detector for electron-hadron discrimination, a tracking system consisting of a set of 6 superconducting coils producing a toroidal field and drift chambers and a multiplicity and electron trigger array for additional electron-hadron discrimination and event characterization. A two-stage trigger system enhances events containing electrons. The physics program is focused on the investigation of hadron properties in nuclei and in the hot and dense hadronic matter. The detector system is characterized by an 85% azimuthal coverage over a polar angle interval from 18 to 85 degree, a single electron efficiency of 50% and a vector meson mass resolution of 2.5%. Identification of pions, kaons and protons is achieved combining time-of-flight and energy loss measurements over a large momentum range. This paper describes the main features and the performance of the detector system

Prescribing growth type of complete Riemannian manifolds of bounded geometry

We describe certain properties of growth types of nondecreasing sequences. We build a complete, connected Riemannian surface of bounded geometry and of a given growth type provided that the type satisfies some natural conditions

BTEX compounds identification by means of gas sensors arrays

BTEX compounds can cause a threat to environment and human health. For this reason measurement devices are needed for rapid identification of such pollutants. The paper presents the results of recognition of mixtures of benzene, toluene, ethylbenzene and xylenes in humid air by means of two gas sensor arrays and linear discriminant analysis. Measurements were conducted during stabilization/solidification processes of contaminated soils. High classification ratios were obtained for both arrays (I: 88%–94%; II: 94%–96%). Improvement of identification was achieved when two copies of every sensor were included in analysis – classification rates reached 97.1–100%

BTEX compounds identification by means of gas sensors arrays

BTEX compounds can cause a threat to environment and human health. For this reason measurement devices are needed for rapid identification of such pollutants. The paper presents the results of recognition of mixtures of benzene, toluene, ethylbenzene and xylenes in humid air by means of two gas sensor arrays and linear discriminant analysis. Measurements were conducted during stabilization/solidification processes of contaminated soils. High classification ratios were obtained for both arrays (I: 88%–94%; II: 94%–96%). Improvement of identification was achieved when two copies of every sensor were included in analysis – classification rates reached 97.1–100%

Renewable energy sources for gas preheating

To ensure proper gas supply parameters, to the polish natural gas distribution network, which includes about 900 pressure reduction stations (PRS), requires high energy consumption for gas heating, that amounts to approx. 700 TJ/year. This value can be significantly reduced by using renewable energy sources (e.g. ground heat exchangers, heat pumps) in polish gas preheating PRS. This paper presents the analysis of some applications for gas preheating by using gas absorption heat pump and combination of heat pump and ground heat exchanger. The results confirm a noticeable heat energy savings at the PRS by 44%

Low- and Medium-Cost Sensors for Tropospheric Ozone Monitoring—Results of an Evaluation Study in Wrocław, Poland

The paper presents the results of a 1.5-year evaluation study of low- and medium-cost ozone sensors. The tests covered electrochemical sensors: SensoriC O3 3E 1 (City Technology) and semiconductor gas sensors: SM50 OZU (Aeroqual), SP3-61-00 (FIS) and MQ131 (Winsen). Three copies of each sensor were enclosed in a measurement box and placed near the reference analyser (MLU 400). In the case of SensoriC O3 3E 1 sensors, the R2 values for the 1-h data were above 0.90 for the first 9 months of deployment, but a performance deterioration was observed in the subsequent months (R2 ≈ 0.6), due to sensor ageing processes. High linear relationships were observed for the SM50 devices (R2 > 0.94), but some periodic data offsets were reported, making regular checking and recalibration necessary. Power-law functions were used in the case of SP3-61-00 (R2 = 0.6–0.7) and MQ131 (R2 = 0.4–0.7). Improvements in the fittings were observed for models that included temperature and relative humidity data. In the case of SP3-61-00, the R2 values increased to above 0.82, while for MQ131 they increased to above 0.86. The study also showed that the measurement uncertainty of tested sensors meets the EU Directive 2008/50/EC requirements for indicative measurements and, in some cases, even for fixed measurements

Optical particulate matter sensors in PM2.5 measurements in atmospheric air

Monitoring systems are needed to obtain information about particulate matter (PM) concentrations and to make such information accessible to the public. Small, low-cost, optical sensors could be used to improve the spatial and temporal resolution of PM data. The paper presents results of collocated comparison of four low-cost PM sensors and TEOM analyser, conducted from 20-08-2017 to 24-12-2017 in Wrocław, Poland. Plantower PMS7003 and Nova Fitness SDS011 sensors proved to be the best in terms of precision and were linearly correlated with TEOM data. Alphasense OPC-N2 sensors exhibited only moderate precision and linearity. Winsen ZH03A sensors had low repeatability between units and only one copy demonstrated good operation possibilities. All tested sensors had a bias in relation to PM2.5 concentrations obtained from TEOM