Measurement Of Breakdown Research Articles

Comparison of Si and SiC MOSFETs responses to electrical stress and the observation of parameter recovery in SiC MOSFET by stress superposition

In this study we examined the effects of room temperature DC and AC electrical stress on Si and SiC n-channel metal-oxide-semiconductor field effect transistors (MOSFETs). Measurement of threshold voltage, transconductance, subthreshold swing, charge pumping, and gate oxide breakdown are used to compare the impact of stress on Si MOSFETs and SiC MOSFETS, as well as to understand the processes of carrier injection and trapping at oxide and interface defects. DC stress is observed to promote negative charge buildup in the gate oxide and interface in Si MOSFETs. However, in SiC MOSFETs the net charge buildup sign alternates between negative and positive as the DC stress polarity is changed from positive to negative, respectively. For the same stress level, relative degradation in parameters of SiC MOSFETs are significantly smaller than those in Si MOSFETs, where in the latter interface state density, conductance, and subthreshold swing have degraded by up to 400%.The change of charge buildup sign explains our observation that degradation in SiC MOSFETs subjected to AC bipolar stress is insignificantly small, whereas AC stressing of Si MOSFETs is observed to be much more severe. Also, the superposition of alternating DC stress polarity eliminates the stress induced degradation in SiC MOSFETs thus enabling a straightforward process for parameter reconfiguration and recovery.

Measurement of particle agglomeration and aggregate breakdown of reclaimed asphalt pavement

Cold milling of old asphalt pavement is widespread in pavement resurfacing. It produces reclaimed asphalt pavement (RAP) and changes the state of the old asphalt pavement; the pavement is cut into particles, known as RAP particles. RAP particles are composed of many smaller aggregates bonded by the aged binder (particle agglomeration). The aggregates contained in the old pavement can be crushed into smaller pieces in the milling operation (aggregate breakdown). Particle agglomeration increases the risk of insufficient moisture stability and fatigue resistance of the recycled asphalt mixture; aggregate breakdown often prevents the use of a higher RAP content in the new mixture. In this study, the effect of these two problems is studied through a pavement maintenance project. The effect of milling speed on the RAP particle agglomeration rate is evaluated. The size-susceptibility of the agglomerate d particles, gradation deviation of the recycled mixture, and morphology classification of RAP particles are discussed. The effect of milling speed on aggregate breakdown is also investigated. The results show that approximately 30%–50% of RAP particles are made of aggregates smaller than the corresponding particle size. The agglomeration rate increases with an increase in milling speed and RAP particle size. High milling speed produces a lower rate of aggregate breakdown, resulting in a higher coarse aggregate content and a lower filler and fine aggregate content than a low milling speed.

Impact of Electrical Stress on Defect Generation in Thin GeO2/Ge Gate Stacks Fabricated by Thermal Oxidation

The impact of electrical stress on the defect generation behaviors in thin GeO2/n-Ge gate stacks has been investigated through the measurement of the time-dependent dielectric breakdown (TDDB) and the stress-induced leakage current (SILC) characteristics. A multiple-spot breakdown (BD) event is confirmed, as well as a larger SILC generation probability compared with that in SiO2/Si structures. It is found that the slow trap generation is dominant by the amount of injected electron fluence ( ${Q} _{{\text {inj}}}$ ), and the fix charge generation is attributed to both ${Q} _{{\text {inj}}}$ and GeO2 thickness.

A novel stable isotope tracer method to simultaneously quantify skeletal muscle protein synthesis and breakdown

Background/aimsMethodological challenges have been associated with the dynamic measurement of muscle protein breakdown (MPB), as have the measurement of both muscle protein synthesis (MPS) and MPB within the same experiment. Our aim was to use the transmethylation properties of methionine as proof-of-concept to measure rates of MPB via its methylation of histidine within skeletal muscle myofibrillar proteins, whilst simultaneously utilising methionine incorporation into bound protein to measure MPS. ResultsDuring the synthesis measurement period, incorporation of methyl[D3]-13C-methionine into cellular protein in C2C12 myotubes was observed (representative of MPS), alongside an increase in the appearance of methyl[D3]-methylhistidine into the media following methylation of histidine (representative of MPB). For further validation of this approach, fractional synthetic rates (FSR) of muscle protein were increased following treatment of the cells with the anabolic factors insulin-like growth factor-1 (IGF-1) and insulin, while dexamethasone expectedly reduced MPS. Conversely, rates of MPB were reduced with IGF-1 and insulin treatments, whereas dexamethasone accelerated MPB. ConclusionsThis is a novel stable isotope tracer approach that permits the dual assessment of muscle cellular protein synthesis and breakdown rates, through the provision of a single methionine amino acid tracer that could be utilised in a wide range of biological settings.

Advances in stable isotope tracer methodology part 2: new thoughts about an “old” method—measurement of whole body protein synthesis and breakdown in the fed state

Whole-body protein turnover (protein synthesis, breakdown, and net balance) model enables quantification of the response to a variety of circumstances, including the response to meal feeding. In the fed state,...

Altered Vascular Permeability in Migraine-associated Brain Regions: Evaluation with Dynamic Contrast-enhanced MRI.

Background Recent studies showed the possible association between inflammation-induced blood-brain barrier (BBB) structural changes followed by greater permeability of the BBB and chronic pain. Thus, measurement of BBB breakdown would be a valuable aid in the diagnosis in migraine. Dynamic contrast material-enhanced (DCE) MRI can determine perfusion and permeability properties related to the BBB. Purpose To evaluate the relationship between permeability of the BBB in migraine-associated brain regions by using DCE MRI. Materials and Methods In this prospective study, from September 2016 to December 2017, 56 study participants underwent DCE MRI after gadobutrol administration and were classified into migraine (n = 35) and healthy control (n = 21) groups. Automatic volumetric segmentation was performed on the pre-contrast-enhanced T1-weighted images by using FreeSurfer, and migraine-associated brain region masks were extracted by using the software NordicICE. The corresponding maps for pharmacokinetic parameters Ktrans (the volume transfer constant) and Vp (the fractional plasma volume) were coregistered with the region-of-interest masks, and their mean values of corresponding total volume of interest were calculated. For comparison analyses, the Mann-Whitney tests were used. Receiver operating characteristic curve analysis and Spearman rank correlation tests were used to identify correlations between clinical characteristics and the aforementioned perfusion parameters. Results Mean age was younger in the migraine group (mean ± standard deviation, 57 years ± 12) than in the healthy control group (mean, 71 years ± 8) (P < .001). In the migraine group, the mean value of Vp in the left amygdala (median, 0.27 mL/100 g) was lower than that in the healthy control group (median, 0.39 mL/100 g) (P = .04). The mean value of Vp in the left amygdala was correlated with the intensity of headache attack in participants with migraine (correlation coefficient, -0.34; P = .04). Conclusion Lower fractional plasma volume in the left amygdala was observed in participants with migraine than in healthy participants. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Carroll and Ginat in this issue.

Electrostrictive Mechanism of Liquid Breakdown in Strongly Nonhomogeneous Field under the Action of Nanosecond Voltage Pulse

Electrostriction mechanism of breakdown in polar liquid caused by high-voltage nanosecond pulse is studied. Nonstationary motion of liquid in the pin-to-plane system exposed to a pulse with peak voltage of 30 kV and 6-ns duration is numerically analyzed. Cavities in which the breakdown can be initiated are formed in the vicinity of the tip electrode. Dimensions of such cavities are estimated, and the conditions for formation are formulated. Profiles of voltage and current pulses are measured for breakdown in water and air. The velocity of breakdown development in air is determined using the time delay of the pulse measured by the shunt of discharge current at several interelectrode distances. The proposed method has limitations in the measurement of breakdown in water due to the effect of displacement current that exceeds the discharge current.

Measurement of Continuum Breakdown During Disk Spindown in Low-Pressure Air

The deceleration torque during spindown of a disk is measured across a range of air pressures on three aluminum disks. The diameters of the disk are 0.15, 0.17, and 0.21 m; the range of pressures is 0.71 Pa to atmospheric pressure; and the angular velocities range approximately from 400 to 3300 rpm. The results are compared to computational fluid dynamics for the continuum flow regime and analytical results for the free molecular flow regime. The torque is nondimensionalized using dynamic viscosity of air, instantaneous angular velocity, and the disk diameter and is plotted against Reynolds number. Results show that the nondimensional curves from atmospheric pressure through 100 Pa collapse on each other for all disk diameters and agree with computational-fluid-dynamics results. At low pressures, the nondimensional torque does not change with Reynolds number. The analytically obtained free molecular flow torque is compared with the experimental results at the lowest ambient pressures, and the value of momentum accommodation coefficient is computed to be . The value is consistent for all disk sizes. The scale used for nondimensionalization suggests self-similarity, and therefore continuity, in the spindown experiments between pressures of 100 Pa and atmospheric pressure. The deviation of the nondimensional curves below this pressure suggests continuum breakdown.

Risk assessment approach for e-cigarette flavours

INTRODUCTION Flavours are an important aspect of the e-cigarette sensory experience. The e-cigarette aerosol is generated by a heating coil vapourising the e-liquid. The vapourisation temperature has been estimated to reach up to 350oC [1], higher coil temperatures have been reported in the absence of e-liquid [2]. Our toxicological risk assessment approach to flavours considers both the flavour itself and the identification, measurement and risk assessment of any potential thermal breakdown and/or reaction products.

Corrosion Monitoring of Flexible Metallic Substrates for Dye-Sensitized Solar Cells

Two techniques for monitoring corrosion within a dye-sensitized solar cell (DSC) system are presented, which enable continuous, high sensitivity, in situ measurement of electrolyte breakdown associated with DSCs fabricated on metals. The first method uses UV/Vis reflectance spectrophotometry in conjunction with encapsulation cells, which incorporate a 25 μm thick electrolyte layer, to provide highly resolved triiodide absorption data. The second method uses digital image capture to extract colour intensity data. Whilst the two methods provide very similar kinetic data on corrosion, the photographic method has the advantage that it can be used to image multiple samples in large arrays for rapid screening and is also relatively low cost. This work shows that the triiodide electrolyte attacks most metals that might be used for structural applications. Even a corrosion resistant metal, such as aluminium, can be induced to corrode through surface abrasion. This result should be set in the context with the finding reported here that certain nitrogen containing heterocyclics used in the electrolyte to enhance performance also act as corrosion inhibitors with significant stabilization for metals such as iron. These new techniques will be important tools to help develop corrosion resistant metal surfaces and corrosion inhibiting electrolytes for use in industrial scale devices.

Measurement of S-Band Microwave Gas Breakdown by Enhancing the Electric Field in a Waveguide

With the development of narrow-band high-power-microwave (HPM) technology, air breakdown has become a serious problem that concerns to the HPM applications. A new method is presented in this paper to determine the electric field of the microwave air breakdown near the atmosphere pressures. Two metal pins were used to strengthen the microwave electric field in a sealed waveguide, putting on the symmetry axis. Some parameters such as gas pressure, temperature, and humidity could be changed conveniently to achieve gas breakdown. Experiment was carried out at the S-band (2.86-GHz) microwave of 180-ns duration and 5-MW peak power, and typical phenomena of plasmas introduced by microwave are analyzed. Furthermore, a new definition of breakdown threshold has been proposed based on breakdown probability, and the electric field threshold is also analyzed.

Measurement of skeletal muscle collagen breakdown by microdialysis

Exercise increases the synthesis of collagen in the extracellular matrix of skeletal muscle. Breakdown of skeletal muscle collagen has not yet been determined because of technical limitations. The purpose of the present study was to use local sampling to determine skeletal muscle collagen breakdown. Microdialysis fibers were tested in vitro to predict bath hydroxyproline (OHP) concentrations. We used an N-methyl-N-[tert-butyldimethyl-silyl]trifluoroacetimide derivative to analyze OHP using gas chromatography-mass spectroscopy (GC-MS) and compared the results with a colorimetric OHP assay. Ten young, healthy male subjects performed a bout of resistance exercise with one leg, followed 17-21 h later by in vivo skeletal muscle sampling by microdialysis in exercised (EX) and control (CON) legs. Microdialysis reliably predicted [OHP] in vitro (R(2)=0.90). Analysis with GC-MS was strongly correlated to traditional analysis methods (CON: slope=1.03, R(2)=0.896, and P<0.05, EX: slope=0.795, R(2)=0.896, and P<0.05). We conclude that in vitro, microdialysis fibers were able to measure OHP concentrations and were sensitive to changes in concentrations, a strenuous bout of exercise did not increase skeletal muscle collagen breakdown 17-21 h post-exercise, and our measurement of OHP using GC-MS was in agreement with traditional assays.

Local investigation of thermal dependence of light emission from reverse-biased monocrystalline silicon solar cells

The quality and lifetime of solar cells critically depend on minimization of both bulk and surface imperfections. When a solar cell is reverse-biased with low voltage, weak emission from imperfections (pre-breakdown sites) appears. We report on the local measurement of such breakdown using a scanning near-field optical microscope. Due to the very weak signals, we use a cooled photomultiplier in the photon counting regime to achieve high sensitivity light detection. This technique allows non-destructive detection, localization and high spatial resolution of light-emitting centers originating from different imperfections in the cell. We have found that the emission from these pre-breakdown sites exhibits unique thermal characteristics. As a consequence, the thermal characteristics can distinguish among several kinds of imperfections in monocrystalline silicon solar cells.

Electrical Recovery After Laser-Assisted Discharge for Highly Repetitive Plasma EUV Source

Extreme ultraviolet (EUV) light source is still the key issue for the industrial application of EUV lithography. For the discharge-produced-plasma EUV source, highly repetitive discharge up to tens of kilohertz is required to achieve the sufficient average radiation power at intermediate focus. Electrical recovery of electrode gaps prior to each discharge influences the EUV emission and determines the repetition rate of the discharge. In this paper, electrical recovery after the main discharge is studied for the laser-assisted-discharge (LAD) tin plasma EUV source through the measurement of the electrical breakdown. The electrical recovery process lasts for a few tens to several hundreds of microseconds, and recovery time is proportional to the discharge shot energy. The measured time-varying hold-off and breakdown voltages can provide a basis for the choice of discharge voltage and corresponding maximum repetition rate. Electrical recovery was explained on the basis of dynamic variation of tin discharge products. It suggests that electrical recovery mainly depends on the diffusion of the tin vapor and its density decaying. Tin droplets do not affect the electrical recovery significantly. Larger discharge energy generates denser tin vapor and causes slower electrical recovery process, which limits the maximum repetition rate of the EUV source. In the LAD EUV source, the relative small shot energy is proper for the high-repetition-rate operation.

Organic matter breakdown and ecosystem metabolism: functional indicators for assessing river ecosystem health

River health monitoring traditionally has made use of structural measurements (water quality or taxonomic composition of aquatic organisms). We argue that a more complete assessment of river health should include functional metrics, such as rates of organic matter decomposition and ecosystem metabolism. Leaf breakdown links the characteristics of riparian vegetation with the activity of both aquatic invertebrates and microbial organisms and is affected by natural and human-induced variation in a wide range of environmental factors. Measurement of leaf breakdown is relatively simple and has modest equipment requirements. River metabolism (gross primary productivity and ecosystem respiration) measures the rates of production and use of organic C in river ecosystems as a whole, providing a direct estimate of the food base that determines life-supporting capacity. Metabolism measurements require more sophisticated equipment than do measurements of leaf breakdown, but improvements in technology have made metabolism measurements relatively easy. We review the factors that influence leaf breakdown and river metabolism and pay particular attention to the effects of human-induced environmental stressors. We also describe how measurements can be standardized and suggest criteria for interpreting functional measures in terms of river ecosystem health. Last, we consider the strengths and weaknesses of both methods as functional measures and provide recommendations for their use as biomonitoring tools.

106 Local Injection of Insulin-Zinc Suspension Stimulates DNA Synthesis in Skin Donor Wound

We have previously reported that local injection of small doses of long-acting insulin-zinc suspension maintained sufficiently high insulin concentration in the wound fluid and accelerated the healing. The present experiment was to measure the rates of cell proliferation (reflected by DNA synthesis) and protein metabolism in the wound. These are the underlying metabolic processes responsible for the healing. Partial thickness skin donor wound was created on the back and indwelling catheters were placed in the carotid artery and jugular vein in adult rabbits under general anesthesia. The wound was covered with Aquaphor gauze, OpSite membrane, and surgical gauze. On day 7 after wounding, the wound was either injected with 0.2 units of insulin-Zn, Zn alone, or no injection; stable isotopes were infused into the jugular vein catheter in conscious rabbits for measurement of DNA synthesis, protein synthesis and breakdown in the wound. The local insulin-Zn injection raised wound insulin concentration to 168 ± 39 μU/ml. In contrast, in the control and Zn groups wound insulin concentrations were below the detectable level. The local injection of insulin-Zn suspension increased (p = 0.03) DNA synthesis in the wound with minor changes in blood glucose concentration which did not require exogenous glucose replacement. In the Zn group, whereas the rate of DNA synthesis tended to increase (p = 0.051 vs. control), the protein net balance (synthesis – breakdown) was lower (p < 0.05) than those in the control and insulin-Zn (Table 1). We conclude that local injection of a small dose (0.2 units insulin) long-acting insulin-Zn suspension stimulated wound DNA synthesis without major systemic side effects thereby providing an effective and safe approach to accelerate wound healing. Although local Zn injection might also stimulate wound DNA synthesis, the benefit on the healing process was limited by decreased net protein deposition. Table 1. Wound DNA and protein metabolism. DNA synthesis Protein synthesis Protein net balance Values are means ± SD in %/d. * p < 0.05 vs. control; + p = 0.051 vs. control;#, p < 0.05 vs. control and insulin-Zn by one-way ANOVA. Control (n = 7) 2.9 ± 0.9 20.5 ± 8.4 7.9 ± 6.0 Insulin-Zn (n = 7) 4.2 ± 0.9* 17.9 ± 8.2 9.4 ± 6.4 Zn (n = 7) 4.1 ± 0.9+ 13.0 ± 5.8 −0.2 ± 3.4#

Fabrication of Carbon Nanotube Field Effect Transistors Using Plasma-Enhanced Chemical Vapor Deposition Grown Nanotubes

Single-walled carbon nanotubes are grown using grid-inserted plasma-enhanced chemical vapor deposition (PECVD). The field effect transistor operation was confirmed using the PECVD grown carbon nanotubes (CNTs). The preferential growth of the semiconducting nanotubes was confirmed in the grid-inserted PECVD by measuring current–voltage (I–V) characteristics of the devices. Based on the measurement of the electrical breakdown of the metallic CNTs, the probability of growing the semiconducting nanotubes has been estimated to be more than 90%.

No Difference in Lipolysis or Glucose Transport of Subcutaneous Fat Cells Between Moderate-fat and Low-fat Hypocaloric Diets in Obese Women

The objective of the present study was to evaluate the effect of two different diets on lipolysis and lipogenesis in subcutaneous fat cells from obese women. In a ten-week nutritional intervention study, forty women were randomly assigned to a hypoenergetic-2,514 kJ (- 600 kcal/day) diet of either moderate-fat/moderate-carbohydrate or low-fat/high-carbohydrate content. Body weight was equally reduced by approximately 7.5 % in both diet groups (p = 0.58). A subcutaneous adipose tissue biopsy was obtained for subsequent measurement of triglyceride breakdown (lipolysis) using drugs active at different steps of the lipolytic signaling cascade, and lipid synthesis (glucose transport) before and after intervention. No difference was found between the two diet groups at the maximum rate of either lipolysis or adrenoceptor sensitivity (p-values: 0.14 - 0.97). Inhibition of lipolysis by insulin was also similar in both diet groups before and after intervention. Finally, insulin-stimulated glucose transport did not show any changes that could be attributed to the type of diet. In conclusion, our data suggest that macronutrient diet composition has no major influence on glucose transport or mobilization of triglycerides in human subcutaneous fat cells of obese women.

A Novel Glucagon Receptor Antagonist Inhibits Glucagon-Mediated Biological Effects

Glucagon maintains glucose homeostasis during the fasting state by promoting hepatic gluconeogenesis and glycogenolysis. Hyperglucagonemia and/or an elevated glucagon-to-insulin ratio have been reported in diabetic patients and animals. Antagonizing the glucagon receptor is expected to result in reduced hepatic glucose overproduction, leading to overall glycemic control. Here we report the discovery and characterization of compound 1 (Cpd 1), a compound that inhibits binding of 125I-labeled glucagon to the human glucagon receptor with a half-maximal inhibitory concentration value of 181 +/- 10 nmol/l. In CHO cells overexpressing the human glucagon receptor, Cpd 1 increased the half-maximal effect for glucagon stimulation of adenylyl cyclase with a KDB of 81 +/- 11 nmol/l. In addition, Cpd 1 blocked glucagon-mediated glycogenolysis in primary human hepatocytes. In contrast, a structurally related analog (Cpd 2) was not effective in blocking glucagon-mediated biological effects. Real-time measurement of glycogen synthesis and breakdown in perfused mouse liver showed that Cpd 1 is capable of blocking glucagon-induced glycogenolysis in a dosage-dependent manner. Finally, when dosed in humanized mice, Cpd 1 blocked the rise of glucose levels observed after intraperitoneal administration of exogenous glucagon. Taken together, these data suggest that Cpd 1 is a potent glucagon receptor antagonist that has the capability to block the effects of glucagon in vivo.

Measurement and Device Simulation of Avalanche Breakdown in High-Voltage 4H-SiC Diodes Including the Influence of Macroscopic Defects

Measurement and Device Simulation of Avalanche Breakdown in High-Voltage 4H-SiC Diodes Including the Influence of Macroscopic Defects