Highly Strain-Stable Intrinsically Stretchable Olfactory Sensors for Imperceptible Health Monitoring.

Intrinsically stretchable gas sensors possess outstanding advantages in seamless conformability and high-comfort wearability for real-time detection toward skin/respiration gases, making them promising candidates for health monitoring and non-invasive disease diagnosis and therapy. However, the strain-induced deformation of the sensitive semiconductor layers possibly causes the sensing signal drift, resulting in failure in achievement of the reliable gas detection. Herein, a surprising result that the stretchable organic polymers present a universal strain-insensitive gas sensing property is shown. All the stretchable polymers with different degrees of crystallinity, including indacenodithiophene-benzothiadiazole (PIDTBT), diketo-pyrrolo-pyrrole bithiophene thienothiophene (DPPT-TT) and poly[4-(4,4-dihexadecyl-4H-cyclopenta[1,2-b:5,4-b']dithiophen-2-yl)-alt-[1,2,5]thiad-iazolo [3,4-c] pyridine] (PCDTPT), show almost unchanged gas response signals in the different stretching states. This outstanding advantage enables the intrinsically stretchable devices to imperceptibly adhere on human skin and well conform to the versatile deformations such as bending, twisting, and stretching, with the highly strain-stable gas sensing property. The intrinsically stretchable PIDTBT sensor also demonstrates the excellent selectivity toward the skin-emitted trimethylamine (TMA) gas, with a theoretical limit of detection as low as 0.3 ppb. The work provides new insights into the preparation of the reliable skin-like gas sensors and highlights the potential applications in the real-time detection of skin gas and respiration gas for non-invasive medical treatment and disease diagnosis.

Assessment of tight-binding models for high-harmonic generation in zinc blende materials.

Using a simulator for semiconductor Bloch equations (SBEs) accounting for the entire Brillouin zone, we examine the tight-binding (TB) description for zinc blende structure as a model for high-harmonic generation (HHG). We demonstrate that TB models of GaAs and ZnSe exhibit second-order nonlinear coefficients that compare favorably with measurements. For the higher-order portion of the spectrum, we use the results published by Xia et al. in Opt. Express26, 29393 (2018)10.1364/OE.26.029393 and show that the HHG spectra measured in reflection can be closely reproduced by our simulations free of adjustable parameters. We conclude that despite their relative simplicity, the TB models of GaAs and ZnSe represent useful tools to study both the low- and higher-order harmonic response in realistic simulations.

Stable antiferromagnetic property and tunable electronic structure of two-dimensional MnPX3(X = S and Se) from pristine structure to Janus phase.

Transition-metal phosphorus trichalcogenides have been considered as very promising two-dimensional (2D) magnetic candidates up-to-date. We performed a systematical first-principles study on the electronic structures and magnetic properties of pristine MnPX3(X = S and Se) and Janus Mn2P2S3Se3monolayers. All monolayers behave as a direct-band-gap semiconductor in antiferromagnetic ground state which is caused by strong direct and indirect exchange interactions. It is found that the electronic structures and magnetic properties can be manipulated by Janus phase. The calculated band gap is 2.44 eV, 1.80 eV and 1.86 eV for MnPS3, MnPSe3and Mn2P2S3Se3with a valley polarization with consideration of spin-orbital coupling (SOC), respectively. In particular, significant energy-splittings emerge in the SOC-band structures of Janus Mn2P2S3Se3due to its broken-inversion-symmetry. Estimated by Monte Carlo simulations, the Néel temperature is 96 K, 71 K and 79 K based on Ising model while halved down to 41 K, 33 K and 36 K on the basis ofXYmodel for MnPS3, MnPSe3and Mn2P2S3Se3, respectively, indicating theXYmodel should be more reliable to describe the spin dynamics. Our research offers an insight into the magnetic mechanism and paves a feasible path to modulate the magnetism for 2D magnets in realistic applications on spintronics.

An artificial neural network chip based on two-dimensional semiconductor.

Recently, research on two-dimensional (2D) semiconductors has begun to translate from the fundamental investigation into rudimentary functional circuits. In this work, we unveil the first functional MoS2 artificial neural network (ANN) chip, including multiply-and-accumulate (MAC), memory and activation function circuits. Such MoS2 ANN chip is realized through fabricating 818 field-effect transistors (FETs) on a wafer-scale and high-homogeneity MoS2 film, with a gate-last process to realize top gate structured FETs. A 62-level simulation program with integrated circuit emphasis (SPICE) model is utilized to design and optimize our analog ANN circuits. To demonstrate a practical application, a tactile digit sensing recognition was demonstrated based on our ANN circuits. After training, the digit recognition rate exceeds 97%. Our work not only demonstrates the protentional of 2D semiconductors in wafer-scale integrated circuits, but also paves the way for its future application in AI computation.

Systematic Risk Analysis of Semiconductor Global Market Based on Deep Feature Fusion K-Means Algorithm.

As the global semiconductor industry has entered a new round of rapid growth, it has also entered a golden cycle of economic growth. Semiconductor companies increase their intrinsic value through financing, industry mergers and acquisitions, and venture capital searches. At the same time, market investors pay more attention to the intrinsic value of companies when looking for good investment targets. Therefore, the systematic risk assessment of the global semiconductor market has become a common concern of market investors and corporate management. In this context, this paper found a method that can assess the systemic risk of the semiconductor global market, which is to use the K-means algorithm based on deep feature fusion. This paper analyzed the algorithm in depth, analyzed the quantum space of tensors, and used the definition of cluster fusion to obtain the relationship between the projection matrices U and V. Experiments were carried out on the improved algorithm, and market research was conducted on a multinational semiconductor company A, which mainly included the basic statistics of the rate of return and the ACF and PACF coefficients of the rate of return series. Finally, the stock risk comparison of company A and company B in the same period was carried out. The experimental results showed that comparing the three items of compound growth rate, coefficient of variation, and active rate coefficient, the highest compound growth rate was 0.41, which came from Category 2, the highest variation coefficient was 2.31, which came from Category 10, and the highest active rate coefficient was 1.78, which came from Category 9. The experimental content was completed well.

A closed-loop recycling process for carbon fiber-reinforced polymer waste using thermally activated oxide semiconductors: Carbon fiber recycling, characterization and life cycle assessment.

The objective of this study is to investigate the properties of recycled carbon fiber (rCF) and its environmental impact, with a specific focus on the energy consumption of the recycling process based on the use of thermally activated oxide semiconductors (TASC). The mechanical and surface properties of rCF obtained under the optimal process parameters were characterized. The life cycle assessment method was used to evaluate the environmental impact of a closed-loop recycling process for carbon fiber-reinforced polymer (CFRP) waste using TASC. The results indicated that the decomposition rate of resin was 95.5 %, and no carbonaceous solid was generated. The gaseous produced of the recycling process were mainly CO2 and H2O, and no liquid products were produced. The surface oxidation degree of rCF was relatively slight. COOH was generated on the surface of rCF, which was conducive to improving the interfacial adhesion viscosity with resin. The monofilament tensile strength of rCF was maintained above 97 %. Compared with landfill and incineration, CFRP waste recycling using TASC can make global warming potential, acidification potential and eutrophication potential reduced by 28 %, 32 %, and 25 %, respectively. Ozone layer depletion potential, human toxicity potential and terrestrial ecotoxicity potential in disposing CFRP waste using TASC were 30 %, 21 % and 41 % of that using pyrolysis, respectively. The energy consumption in carbon fiber recycling by TASC was only 23 % of that in virgin carbon fiber manufacturing. TASC is found to be a promising potential strategy for managing CFRP waste.

Monte Carlo simulation of semiconductor-based detector in mixed radiation field in the atmosphere.

Calculation of radiation protection quantities in tissue equivalent material from measurements using semiconductor detectors requires correction factors for conversion of the measured values in the semiconductor material to the tissue equivalent material. This approach has been used many times in aircraft and for space dosimetry. In this paper, we present the results of Monte Carlo simulations which reveal the need to take into account both the radiation field and the detector material when performing the conversion of measured values to radiation protection quantities. It is shown that for low Z target material, most of the dose equivalent at aviation altitudes comes from neutrons originating from nuclear reactions, while in high Z targets most of the dose equivalent comes from photons, originating from electromagnetic reactions.

Two Semiconductor Companies' Financial Support Compensation (FSC) Programs for Semiconductor Workers with Suspected Work-Related Diseases (WRDs).

This study described two companies' financial compensation programs for semiconductor workers with suspected work-related diseases (WRDs) and discussed the major related issues. The key contents of the programs found on the websites opened by two semiconductor companies (Samsung and SK Hynix) were cited. In order to select the suspected WRDs for the FSC, all available epidemiologic studies related to health problems conducted in the semiconductor industry were reviewed. Most program contents are similar, although the amount of financial compensation and a few types of disease available for compensation differ between the companies. The group of cancer, rare disease, childhood rare disease among children born to semiconductor workers (hereafter selected diseases among offspring), and fetal loss, including spontaneous abortion (SAB) and stillbirth, were considered for compensation. An employment duration of longer than one year on a semiconductor production line is required for FSC for cancer or rare disease. The FSC for SAB and offspring disease require a period of employment longer than one month, either before three months prior to conception or between conception and childbirth. The maximum amount of compensation per type of cancer and rare disease was fixed based on the medical treatment fee. The FSC programs of the two companies have been operated successfully to date. These programs are arguably considered to contribute to resolving the conflict between companies and workers with WRDs.

Biological Assessment of Potential Exposure to Occupational Substances in Current Semiconductor Workers with at Least 5 Years of Employment.

BACKGROUND: this study aimed to conduct a biological assessment of the potential exposure to carcinogenic substances in current semiconductor workers. METHODS: A cross-sectional study was conducted on 306 semiconductor workers. The assessed biomarkers were as follows: (benzene) urine S-phenylmercapturic, trans,trans-muconic acid, blood benzene; (trichloroethylene) urine trichloroacetic acid; (2-ethoxyethanol) 2-ethoxyacetic acid; (arsine) urine arsenic3+, arsenic5+, monomethylarsonic, dimethylarsinic acid, arsenobetaine; (shift work) 6-hydroxymelatonin; (smoking) cotinine, and (radiation). The detection rate of these materials is defined as more than the biological exposure index (BEI) or the previous reference value. RESULTS: Some workers exposed to trans,trans-muconic acid, trichloroacetic acid, and arsenic5+ showed high BEI levels. Generally, there was no difference according to job categories, and workers were suspected to be exposed to other sources. The melatonin concentration tended to decrease when working at night, and cotinine was identified as an excellent surrogate marker for smoking. In the case of radiation exposure, there was no significant difference in the number of stable chromosome translocation in 19 semiconductor workers. Their estimated radiation exposure level was below the limit of detection (LOD) or near the LOD level. CONCLUSION: In this study, most carcinogens were below the BEI level, but verification through re-measurement was needed for workers who were identified to have a high BEI level. For continuous monitoring, a prospective cohort is necessary to deal with the healthy worker effect and assess additional materials.

Low-cost micro-spectrometer based on a nano-imprint and spectral-feature reconstruction algorithm.

Reconstructive micro-spectrometers have shown great potential in many fields such as medicine, agriculture, and astronomy. However, the performance of these spectrometers is seriously limited by the spectral varieties of response pixels and anti-noise ability of reconstruction algorithms. In this work, we propose a spectral reconstruction (SR) algorithm, whose anti-noise ability is at least four times better than the current algorithms. A micro-spectrometer is realized by fabricating a large number of Fabry-Perot (FP) micro-filters onto a cheap complementary metal-oxide semiconductor (CMOS) chip for demonstration by using a very high-efficiency technology of nano-imprinting. Nano-imprint technology can complete hundreds of spectral pixels with rich spectral features at one time and with low cost. In cooperation with the SR algorithm, such a micro-spectrometer can have a spectral resolution as high as 3 nm with much lower angular sensitivity than a photonic crystal-based micro-spectrometer. It can obtain the target's spectrum from only a single shot, which has wide applications in spectral analysis etc.

Exploitation of distillation for energy-efficient and cost-effective environmentally benign process of waste solvents recovery from semiconductor industry.

The waste solvent is unavoidably generated from the high solvent dependable processes. One of them is the semiconductor industry. The waste solvent is frequently incinerated to eliminate hazardous waste and this practice raises the issue of environmental and treatment costs. Thus, recovery of waste solvent is a substantial environmental mitigation option. This study explores the recovery of multicomponent waste solvents from the semiconductor industry. To achieve a greener and energy-efficient process, the recovery process is proposed through investigation of mixture thermodynamic behavior, process design, optimization, economics, and integration of renewable energy for environmental advantages. Herein, Distillation, a practical technology option for solvent recovery, with green solvent for extractive distillation and a new approach using renewable energy in waste solvent recovery are explored. As the result, waste solvent recovery by distillation with conventional energy exhibits bold advantages to cost and lower carbon process compared to waste disposal. The integration of renewable energy with about 37 % share of conventional energy as the backup indicates the highest annual cost-saving and reduces about 89.4 % of annual carbon emission compared to carbon emission from waste disposal.

Electrodissolution-Coupled Hafnium Alkoxide Synthesis with High Environmental and Economic Benefits.

The conventional thermal method of preparing hafnium alkoxides [Hf(OR)4 , R=alkyl] - excellent precursors for gate-dielectric HfO2 on semiconductors - is severely hindered by its unsatisfactory environmental and economic burdens. Herein, we propose a promising electrodissolution-coupled Hf(OR)4 synthesis (EHS) system for green and efficient electrosynthesis of Hf(OR)4 . The operational principle of the electrically driven system consists of two simultaneous heterogeneous reactions of Hf dissolution and alcohol dehydrogenation, plus a spontaneous solution-based combination reaction. In applying ethanol as solvent and Hf metal as electrodissolution medium, we achieved waste-free production of high-purity hafnium ethoxide [Hf(OEt)4 ] with an equivalent "a concomitant" reduction in CO2 emission of 187.33 g CO2 per kg Hf(OEt)4 and a high net profit of 30 477 USD per kg Hf(OEt)4 . This system is very competitive with the thermal process, which unavoidably releases substantial waste and CO2 for a net profit of 27 700 USD per kg Hf(OEt)4 . We anticipate that the environmental and economic benefits of the EHS process could pave the way for its practical application.

A Portable Device for Methane Measurement Using a Low-Cost Semiconductor Sensor: Development, Calibration and Environmental Applications.

Methane is a major greenhouse gas and a precursor of tropospheric ozone, and most of its sources are linked to anthropogenic activities. The sources of methane are well known and its monitoring generally involves the use of expensive gas analyzers with high operating costs. Many studies have investigated the use of low-cost gas sensors as an alternative for measuring methane concentrations; however, it is still an area that needs further development to ensure reliable measurements. In this work a low-cost platform for measuring methane within a low concentration range was developed and used in two distinct environments to continuously assess and improve its performance. The methane sensor was the Figaro TGS2600, a metal oxide semiconductor (MOS) based on tin dioxide (SnO2). In a first stage, the monitoring platform was applied in a small ruminant barn after undergoing a multi-point calibration. In a second stage, the system was used in a wastewater treatment plant together with a multi-gas analyzer (Gasera One Pulse). The calibration of low-cost sensor was based on the relation of the readings of the two devices. Temperature and relative humidity were also measured to perform corrections to minimize the effects of these variables on the sensor signal and an active ventilation system was used to improve the performance of the sensor. The system proved to be able to measure low methane concentrations following reliable spatial and temporal patterns in both places. A very similar behavior between both measuring systems was also well noticeable at WWTP. In general, the low-cost system presented good performance under several environmental conditions, showing itself to be a good alternative, at least as a screening monitoring system.

Area efficient camouflaging technique for securing IC reverse engineering.

Reverse engineering is a burning issue in Integrated Circuit (IC) design and manufacturing. In the semiconductor industry, it results in a revenue loss of billions of dollars every year. In this work, an area efficient, high-performance IC camouflaging technique is proposed at the physical design level to combat the integrated circuit's reverse engineering. An attacker may not identify various logic gates in the layout due to similar image output. In addition, a dummy or true contact-based technique is implemented for optimum outcomes. A library of gates is proposed that contains the various camouflaged primitive gates developed by a combination of using the metal routing technique along with the dummy contact technique. This work shows the superiority of the proposed technique's performance matrix with those of existing works regarding resource burden, area, and delay. The proposed library is expected to make open source to help ASIC designers secure IC design and save colossal revenue loss.

Determination of the surface dose of a water phantom using a semiconductor detector for diagnostic kilovoltage x-ray beams.

PURPOSE: To determine the surface dose of a water phantom using a semiconductor detector for diagnostic kilovoltage x-ray beams. METHODS: An AGMS-DM+ semiconductor detector was calibrated in terms of air kerma measured with an ionization chamber. Air kerma was measured for 20 x-ray beams with tube voltages of 50-140 kVp and a half-value layer (HVL) of 2.2-9.7 mm Al for given quality index (QI) values of 0.4, 0.5, and 0.6, and converted to the surface dose. Finally, the air kerma and HVL measured by the AGMS-DM+ detector were expressed as a ratio of the surface dose for 10 × 10 and 20 × 20 cm2 fields. The ratio of both was represented as a function of HVL for the given QI values and verified by comparing it with that calculated using the Monte Carlo method. RESULTS: The air kerma calibration factor, CF, for the AGMS-DM+ detector ranged from 0.986 to 1.016 (0.9% in k = 1). The CF values were almost independent of the x-ray fluence spectra for the given QI values. The ratio of the surface dose to the air kerma determined by the PTW 30,013 chamber and the AGMS-DM+ detector was less than 1.8% for the values calculated using the Monte Carlo method, and showed a good correlation with the HVL for the given QI values. CONCLUSION: It is possible to determine the surface dose of a water phantom from the air kerma and HVL measured by a semiconductor detector for given QI values.

Biodegradable Materials for Sustainable Health Monitoring Devices.

The recent advent of biodegradable materials has offered huge opportunity to transform healthcare technologies by enabling sensors that degrade naturally after use. The implantable electronic systems made from such materials eliminate the need for extraction or reoperation, minimize chronic inflammatory responses, and hence offer attractive propositions for future biomedical technology. The eco-friendly sensor systems developed from degradable materials could also help mitigate some of the major environmental issues by reducing the volume of electronic or medical waste produced and, in turn, the carbon footprint. With this background, herein we present a comprehensive overview of the structural and functional biodegradable materials that have been used for various biodegradable or bioresorbable electronic devices. The discussion focuses on the dissolution rates and degradation mechanisms of materials such as natural and synthetic polymers, organic or inorganic semiconductors, and hydrolyzable metals. The recent trend and examples of biodegradable or bioresorbable materials-based sensors for body monitoring, diagnostic, and medical therapeutic applications are also presented. Lastly, key technological challenges are discussed for clinical application of biodegradable sensors, particularly for implantable devices with wireless data and power transfer. Promising perspectives for the advancement of future generation of biodegradable sensor systems are also presented.

Development of cost effective metal oxide semiconductor based gas sensor over flexible chitosan/PVP blended polymeric substrate.

In the present work, biodegradable and flexible chitosan/polyvinylpyrrolidone (CHP) polymeric substrate was fabricated by solvent casting method. This is a novel demonstration of the combination of natural polymer (chitosan) and synthetic polymer (PVP) for next-generation semiconductor device applications. The ZnO thin films were successfully synthesized on these polymeric substrates by facile drop-casting method for gas sensing applications. The hydrogen gas sensing properties of ZnO deposited on the polymeric substrate and SiO2 substrate show similar performance. The structural, morphological, optical, thermal, and tensile strength of the CHP substrate were studied using X-ray diffraction (XRD), Scanning electron microscopy (SEM), UV-visible spectroscopy, Derivative thermogravimetric analysis (DTG), and Universal testing machine (UTM), respectively. Our study suggests that the biodegradable CH/PVP flexible polymeric substrate provides a new way for the implementation of an eco-friendly green substrate in numerous electronic device applications.

Meat quality assessment using Au patch electrode Ag-SnO2/SiO2/Si MIS capacitive gas sensor at room temperature.

An Au patch electrode Ag-SnO2/SiO2/Si MIS capacitive sensor equipped with a microcontroller was designed and developed to sense low concentration (ppb to ppm regime) of volatiles (NH3, TMA, ethanol, and H2S) generated from chicken meat spoilage at room temperature. The quality threshold or the acceptance limit for consumption of chicken meat samples stored at 4 °C, 15 °C and 25 °C using our proposed technique was found to be 105 h, 48 h, and 17 h respectively, highly correlated with TVB-N, TVC, pH and sensory evaluation analysis. When these well established standard methods (TVB-N, TVC and pH analysis) take many hours to complete the analysis involving many complicated steps, our fabricated sensor takes 55 sec to deliver sensing response reflecting the meat spoilage status. The sensor calibrated with our compact technique promises portable and inexpensive onsite rapid and accurate quality assessment of meat spoilage at room temperature.

Energy self-sufficient households with photovoltaics and electric vehicles are feasible in temperate climate.

The idea that households produce and consume their own energy, that is, energy self-sufficiency at a very local level, captures the popular imagination and commands political support across parts of Europe. This paper investigates the technical and economic feasibility of household energy self-sufficiency in Switzerland, which can be seen as representative for other regions with a temperate climate, by 2050. We compare sixteen cases that vary across four dimensions: household type, building type, electricity demand reduction, and passenger vehicle use patterns. We assume that photovoltaic (PV) electricity supplies all energy, which implies a complete shift away from fossil fuel based heating and internal combustion engine vehicles. Two energy storage technologies are considered: short-term storage in lithium-ion batteries and long-term storage with hydrogen, requiring an electrolyzer, storage tank, and a fuel cell for electricity conversion. We examine technological feasibility and total system costs for self-sufficient households compared to base cases that rely on fossil fuels and the existing power grid. PV efficiency and available rooftop/facade area are most critical with respect to the overall energy balance. Single-family dwellings with profound electricity demand reduction and urban mobility patterns achieve self-sufficiency most easily. Multi-family buildings with conventional electricity demand and rural mobility patterns can only be self-sufficient if PV efficiency increases, and all of the roof plus most of the facade can be covered with PV. All self-sufficient cases are technically feasible but more expensive than fully electrified grid-connected cases. Self-sufficiency may even become cost-competitive in some cases depending on storage and fossil fuel prices. Thus, if political measures improve their financial attractiveness or individuals decide to shoulder the necessary investments, self-sufficient buildings may start to become increasingly prevalent.

MOSFET dosimeter characterization in MR-guided radiation therapy (MRgRT) Linac.

PURPOSE: With the increasing use of MR-guided radiation therapy (MRgRT), it becomes important to understand and explore accuracy of medical dosimeters in the presence of magnetic field. The purpose of this work is to characterize metal-oxide-semiconductor field-effect transistors (MOSFETs) in MRgRT systems at 0.345 T magnetic field strength. METHODS: A MOSFET dosimetry system, developed by Best Medical Canada for in-vivo patient dosimetry, was used to study various commissioning tests performed on a MRgRT system, MRIdian® Linac. We characterized the MOSFET dosimeter with different cable lengths by determining its calibration factor, monitor unit linearity, angular dependence, field size dependence, percentage depth dose (PDD) variation, output factor change, and intensity modulated radiation therapy quality assurance (IMRT QA) verification for several plans. MOSFET results were analyzed and compared with commissioning data and Monte Carlo calculations. RESULTS: MOSFET measurements were not found to be affected by the presence of 0.345 T magnetic field. Calibration factors were similar for different cable length dosimeters either placed at the parallel or perpendicular direction to the magnetic field, with variations of less than 2%. The detector showed good linearity (R2  = 0.999) for 100-600 MUs range. Output factor measurements were consistent with ionization chamber data within 2.2%. MOSFET PDD measurements were found to be within 1% for 1-15 cm depth range in comparison to ionization chamber. MOSFET normalized angular response matched thermoluminescent detector (TLD) response within 5.5%. The IMRT QA verification data for the MRgRT linac showed that the percentage difference between ionization chamber and MOSFET was 0.91%, 2.05%, and 2.63%, respectively for liver, spine, and mediastinum. CONCLUSION: MOSFET dosimeters are not affected by the 0.345 T magnetic field in MRgRT system. They showed physics parameters and performance comparable to TLD and ionization chamber; thus, they constitute an alternative to TLD for real-time in-vivo dosimetry in MRgRT procedures.