Li+-stabilized Na-β”-alumina was synthesized through sol-gel based on the Pechini method with Al(NO3)3, NaNO3, and LiNO3 as the metal precursor. Evaluations were done to several different sodium content in order to ...
Li+-stabilized Na-β”-alumina was synthesized through sol-gel based on the Pechini method with Al(NO3)3, NaNO3, and LiNO3 as the metal precursor. Evaluations were done to several different sodium content in order to counterbalance Na2O losses during sintering, as well as different sintering temperature between 1500 – 1700 °C. The evaluations were done by density measurement, impedance spectroscopy, X-ray diffraction, and Scanning Electron Microscopy. The synthesized powder exhibits Na-β”-alumina with measured relative density up to 2.96±0.01 g/cm3. The ionic conductivity achieved was up to 0.23 S/cm at 300 °C with lowest activation energy for conduction of 0.17 eV. Moreover, the Na-β”-alumina phase content achieved was up to 84%.
In this work the existing SRH parametrizations for the FeGa defect are re-evaluated by a deliberately iron contaminated sample set of varied doping densities. The evolution of the cross-over point is analyzed for this...
In this work the existing SRH parametrizations for the FeGa defect are re-evaluated by a deliberately iron contaminated sample set of varied doping densities. The evolution of the cross-over point is analyzed for this aim, due to its characteristic dependency on the defect parameters of the metastable iron states. It can give insight into the defect parameter, whilst being independent of most factors usually limiting evaluations precision. The proposed parameter adjustment provides an improved description of the measurement data compared to the literature parametrizations.
The trapping characteristics of defects related to thermal donors have been studied with transient photoconductance measurements in Cz monocrystalline silicon wafers. The samples were annealed for various lengths of t...
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The trapping characteristics of defects related to thermal donors have been studied with transient photoconductance measurements in Cz monocrystalline silicon wafers. The samples were annealed for various lengths of time to create a range of thermal donor concentrations. The de-trapping time constant was measured using photoconductance decay after the illumination is turned off. In order to obtain an estimate of the de-trapping time constants, the measurements were fitted with exponential terms. We find that the de-trapping time constant is inversely related to the concentration of thermal donors, while trapping is not observed in samples without thermal donors.
The authors demonstrate a method to calculate the cross-correlation scale factor (CCSF) which rescales the time between indoor and outdoor degradation models. The CCSF is further applied to obtain the cross correlatio...
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The authors demonstrate a method to calculate the cross-correlation scale factor (CCSF) which rescales the time between indoor and outdoor degradation models. The CCSF is further applied to obtain the cross correlation coefficients(CCC) between the models of outdoor modules located in three climate zones and the indoor accelerated tests using damp-heat and thermal cycle exposures for five commercial PV module brands. We evaluate and compare the performances of different combinations based on the CCC, to determine the indoor accelerated test which is most closely related to real world conditions at each site. The result shows that the cross correlation coefficients among some combinations between the outdoor model and indoor model are over 0.9, and we further compare the trend of I-V features between indoor and outdoor modules to evaluate the degree of similarity of degradation mechanisms between indoor and outdoor modules. The result obtained from these two comparison methods are in good agreement with each other.
In this work, bar-and disk-shaped resonators were fabricated using Al_(0.84)Sc_(0.16)N thin film. Sensitivity analysis of the resonators' resonance frequencies with respect to the piezoelectric material parameters...
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In this work, bar-and disk-shaped resonators were fabricated using Al_(0.84)Sc_(0.16)N thin film. Sensitivity analysis of the resonators' resonance frequencies with respect to the piezoelectric material parameters revealed that resonance analysis can be used for material parameter extraction. An optimization algorithm is employed to determine the piezoelectric material parameters (s_11)~E, (s_12)~E, and d_(31) of Al_(0.84)Sc_(0.16)N from the length-and radial-extensional mode. Using the piezoelectric constitutive equations and combining the results obtained in this work with the results obtained in a previous work, the stress-charge form of elastic and piezoelectric parameters could be derived.
We demonstrate the first ZnGeP2-based, femtosecond OPA system driven directly by a Thulium-based fiber-laser system operated at 100 kHz. The OPA delivers mid-to-long-infrared tunable pulses with idler energies up to 2...
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A method of optimizing the control parameter of wearable exoskeletons for industrial applications using subjective feedbacks is introduced in this paper. The human sensory system is explained and a method of mapping t...
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A method of optimizing the control parameter of wearable exoskeletons for industrial applications using subjective feedbacks is introduced in this paper. The human sensory system is explained and a method of mapping these perceptions to the control parameter set of the exoskeleton is developed. Subsequently a method for online parameter adjustment based on the kinetic and kinematic quantities is established and the method is verified for a case study with the Stuttgart Exo-Jacket.
In this work we present results of a series of experiments to investigate the origin of the defects causing light and elevated temperature induced degradation (LeTID). It has been demonstrated that LeTID effects can b...
In this work we present results of a series of experiments to investigate the origin of the defects causing light and elevated temperature induced degradation (LeTID). It has been demonstrated that LeTID effects can be observed even in high purity monocrystalline silicon. The experiments are therefore performed on float-zone silicon and feature a variety of process schemes to test important hypotheses on LeTID and reproduce them under more defined conditions. Different surface passivation schemes based on aluminium oxide layers are combined with a designated hydrogenation treatment and subjected to different thermal processes on both p- and n-type wafers. The results on p-type wafers confirm several previous observations concerning, e.g., the influence of silicon nitride layers and the firing peak temperature. However, we do not observe a crucial influence of the specific firing temperature profile in the experiment. The investigated n-type wafers do not feature a typical LeTID behaviour but appear to be affected by the LeTID defect nonetheless. Firstly, we observe an improvement of the effective lifetime under LeTID testing conditions that is driven by an improvement of the bulk lifetime. Secondly, identical pattern are observed in lifetime images of n-type wafers directly after firing and of p-type wafers in the degraded state. These findings strongly indicate that LeTID defects can be present in the initial state of n-type wafers after firing.
Aluminum nitride (AlN) based flexural plate wave (FPW) sensors with buried interdigital transducers (IDTs) were designed, fabricated, and characterized with respect to their application as sensors operating in liquids...
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ISBN:
(纸本)9781509010134
Aluminum nitride (AlN) based flexural plate wave (FPW) sensors with buried interdigital transducers (IDTs) were designed, fabricated, and characterized with respect to their application as sensors operating in liquids. In the proposed device, the IDTs are designed as a buried electrode, and thus, are electrically shielded, enabling full immersion of the sensor into the liquid. The functionality of the proof-of-concept sensors was demonstrated by means of laser Doppler vibrometry and network analyzer measurements in air and water. The fabricated devices showed a mass sensitivity of 240 cm~2/g for loading with de-ionized water which is in good agreement with the theoretically determined mass sensitivity.
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