Abstract: A method for determining tobacco-specific nitrosamines (TSNAs) in cigarette smoke using one-step clean-up coupled with LC-MS/MS is provided, including the following steps: collecting a particulate matter of mainstream cigarette smoke with a Cambridge filter pad, mixing the particulate matter of mainstream cigarette smoke, an internal standards solution and water in a 50 mL plastic centrifuge tube, and vortexing the resulting mixture at room temperature to allow extraction; transferring an extraction solution after filtration to a new centrifuge tube, adding dichloromethane, and vortexing the resulting mixture; centrifuging to collect a dichloromethane extraction solution in a lower layer to another centrifuge tube, and placing the centrifuge tube in a water bath to remove dichloromethane; dissolving the resulting extraction solution in water, and transferring the resulting solution to an autosampler vial for LC-MS/MS analysis.

Abstract: The present disclosure provides a direct current (DC) transformer error detection apparatus for a pulsating harmonic signal, including a DC and pulsating harmonic current output module and an external detected input module, where the DC and pulsating harmonic current output module outputs a DC and a DC superimposed pulsating harmonic current to an internal sampling circuit and a self-calibrated standard resistor array; and the internal sampling circuit converts the input DC and the input DC superimposed pulsating harmonic current into a voltage signal, and sends the voltage signal to an analog-to-digital (AD) sampling and measurement component through a front-end conditioning circuit and a detected input channel. The DC transformer error detection apparatus can complete self-calibration for measurement of the DC and the pulsating harmonic signal on a test site.

Abstract: A method for determining tobacco-specific nitrosamines (TSNAs) in tobacco using one-step clean-up coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) is provided, including the following steps: destemming flue-cured tobacco or sun-cured tobacco, drying, milling, and passing through a sieve; mixing the resulting tobacco, an internal standards solution and water in a plastic centrifuge tube, and vortexing the resulting mixture at room temperature to allow extraction; transferring an extraction solution after filtration to a new centrifuge tube, adding dichloromethane, and vortexing the resulting mixture; centrifuging to collect a dichloromethane extraction solution in a lower layer to another centrifuge tube, and placing the centrifuge tube in a water bath to remove dichloromethane; dissolving the resulting extraction solution in water, and transferring the resulting solution to an autosampler vial for LC-MS/MS analysis.

Abstract: Disclosed is a semiconductor device and a method for fabricating such semiconductor device, specifically a High Electron Mobility Transistor (HEMT) with a back barrier layer for blocking electron leakage and improve threshold voltage. In one embodiment, a semiconductor device, includes: a Gallium Nitride (GaN) layer; a front barrier layer over the GaN layer; a source electrode, a drain electrode and a gate electrode formed over the front barrier layer; a 2-Dimensional Electron Gas (2-DEG) in the GaN layer at a first interface between the GaN layer and the front barrier layer; and a back barrier layer in the GaN layer, wherein the back barrier layer comprises Aluminum Nitride (AlN).

Abstract: A semiconductor structure includes a barrier layer over a channel layer, and a doped layer over the barrier layer. A gate electrode is over the doped layer and a doped interface layer is formed between the barrier layer and the doped layer. The doped interface layer includes a dopant and a metal. The metal has a metal concentration that follows a gradient function from a highest metal concentration to a lowest metal concentration.

Abstract: A method for merging surface skin three-dimensional (3D) data includes the following steps: 1. constructing actually-measured 3D data of a workpiece and 3D data of a design model of the workpiece; 2. calculating a normal vector, a neighborhood radius, and a position of a sphere center of each point in the design model 3D data; 3. finding closest points to the design model 3D data for all points in the actually-measured 3D data; 4. calculating a static closest distance and a dynamic closest distance from each point in the actually-measured 3D data to the closest point in the design model 3D data; 5. constructing an objective function of a surface adaptive distance; 6. minimizing the objective function and calculating a differential motion screw; and 7. updating the actually-measured 3D data and achieving data merging.

Abstract: Disclosed is a semiconductor device and a method for fabricating such semiconductor device, specifically a High Electron Mobility Transistor (HEMT) with a back barrier layer for blocking electron leakage and improve threshold voltage. In one embodiment, a semiconductor device, includes: a Gallium Nitride (GaN) layer; a front barrier layer over the GaN layer; a source electrode, a drain electrode and a gate electrode formed over the front barrier layer; a 2-Dimensional Electron Gas (2-DEG) in the GaN layer at a first interface between the GaN layer and the front barrier layer; and a back barrier layer in the GaN layer, wherein the back barrier layer comprises Aluminum Nitride (AlN).

Abstract: Structures and methods for controlling dopant diffusion and activation are disclosed. In one example, a semiconductor structure is disclosed. The semiconductor structure includes: a channel layer; a barrier layer over the channel layer; a gate electrode over the barrier layer; and a doped layer formed between the barrier layer and the gate electrode. The doped layer includes (a) an interface layer in contact with the barrier layer and (b) a main layer between the interface layer and the gate electrode. The doped layer comprises a dopant whose doping concentration in the interface layer is lower than that in the main layer.

Abstract: A method for merging surface skin three-dimensional (3D) data includes the following steps: 1. constructing actually-measured 3D data of a workpiece and 3D data of a design model of the workpiece; 2. calculating a normal vector, a neighborhood radius, and a position of a sphere center of each point in the design model 3D data; 3. finding closest points to the design model 3D data for all points in the actually-measured 3D data; 4. calculating a static closest distance and a dynamic closest distance from each point in the actually-measured 3D data to the closest point in the design model 3D data; 5. constructing an objective function of a surface adaptive distance; 6. minimizing the objective function and calculating a differential motion screw; and 7. updating the actually-measured 3D data and achieving data merging.

Abstract: A method of manufacturing a High-Electron-Mobility Transistor (HEMT) includes: preparing a substrate; forming a first buffer over the substrate; forming a second buffer over the first buffer, wherein forming the second buffer includes doping a first thickness of a material such as gallium nitride (GaN) with a first concentration of a dopant such as carbon, and doping a second thickness of the material with a second concentration of the dopant such that the second concentration of dopant has a gradient though the second thickness which progressively decreases in a direction away from the first thickness; forming a channel layer such as a GaN channel over the second buffer; forming a barrier layer such as aluminum gallium nitride (AlGaN) over the channel layer; and forming drain, source and gate terminals for the HEMT.

Abstract: Strain relief trenches may be formed in a substrate prior to growth of an epitaxial layer on the substrate. The trenches may reduce the stresses and strains on the epitaxial layer that occur during the epitaxial growth process due to differences in material properties (e.g., lattice mismatches, differences in thermal expansion coefficients, and/or the like) between the epitaxial layer material and the substrate material. The stress and strain relief provided by the trenches may reduce or eliminate cracks and/or other types of defects in the epitaxial layer and the substrate, may reduce and/or eliminate bowing and warping of the substrate, may reduce breakage of the substrate, and/or the like. This may increase the center-to-edge quality of the epitaxial layer, may permit epitaxial layers to be grown on larger substrates, and/or the like.

Abstract: Strain relief trenches may be formed in a substrate prior to growth of an epitaxial layer on the substrate. The trenches may reduce the stresses and strains on the epitaxial layer that occur during the epitaxial growth process due to differences in material properties (e.g., lattice mismatches, differences in thermal expansion coefficients, and/or the like) between the epitaxial layer material and the substrate material. The stress and strain relief provided by the trenches may reduce or eliminate cracks and/or other types of defects in the epitaxial layer and the substrate, may reduce and/or eliminate bowing and warping of the substrate, may reduce breakage of the substrate, and/or the like. This may increase the center-to-edge quality of the epitaxial layer, may permit epitaxial layers to be grown on larger substrates, and/or the like.

Abstract: A method for forming a semiconductor arrangement is provided. The method includes forming a patterned photoresist over a top surface of a substrate. The method includes doping a first portion of the substrate using the patterned photoresist. The method includes removing the patterned photoresist using a gas comprising fluoride, wherein fluoride residue from the gas remains on the top surface of the substrate after removing the patterned photoresist. The method includes treating the substrate with nitrous oxide to remove the fluoride residue.

Abstract: The present invention “A Molecular marker Nicotine Associated SNP 1 for identifying high or nicotine content of tobacco and its kit as well as use thereof” belongs to field of molecular biology technology. The molecular marker Nicotine Associated SNP 1 is a SNP Nitab4.5_0002539:95304 A/G at base No. 95304 of Genomic segment No. 0002539 in tobacco genome version of Nitab v4.5 Genome Scaffolds Edwards2017. The present invention can accurately identify and screen tobacco germplasm resources with high or low nicotine content, and the screened tobacco can be directly used for breeding new tobacco varieties without transgenic methods. At the same time, gene sequence where the SNP site is located can also significantly activate promoters of key enzyme genes in nicotine synthesis pathway.

Abstract: Disclosed is a semiconductor device and a method for fabricating such semiconductor device, specifically a High Electron Mobility Transistor (HEMT) with a back barrier layer for blocking electron leakage and improve threshold voltage. In one embodiment, a semiconductor device, includes: a Gallium Nitride (GaN) layer; a front barrier layer over the GaN layer; a source electrode, a drain electrode and a gate electrode formed over the front barrier layer; a 2-Dimensional Electron Gas (2-DEG) in the GaN layer at a first interface between the GaN layer and the front barrier layer; and a back barrier layer in the GaN layer, wherein the back barrier layer comprises Aluminum Nitride (AIN).

Abstract: A tobacco arsenic transport gene NtNIP7-1 and a cloning method and application thereof are disclosed. A nucleotide sequence of the tobacco arsenic transport gene NtNIP7-1 is shown as SEQ ID: No. 1, and an encoded amino acid sequence thereof is shown as SEQ ID: No. 2. The cloning method of the tobacco arsenic transport gene NtNIP7-1 includes (S1) extracting RNA in tobacco, performing reverse transcription, and obtaining a first-strand cDNA; and (S2) taking the first-strand cDNA obtained by the reverse transcription as a template, synthesizing a specific primer according to sequences of the NtNIP7-1 gene, performing PCR amplification, recovering and purifying a product of the PCR amplification, and sequencing. In the present invention, inhibition of the expression of the tobacco endogenous gene NtNIP7-1 in tobacco plants is able to significantly reduce the arsenic content of tobacco leaves, and has broad application prospects in the field of low arsenic content breeding.

Abstract: A method for forming a semiconductor arrangement is provided. The method includes forming a patterned photoresist over a top surface of a substrate. The method includes doping a first portion of the substrate using the patterned photoresist. The method includes removing the patterned photoresist using a gas comprising fluoride, wherein fluoride residue from the gas remains on the top surface of the substrate after removing the patterned photoresist. The method includes treating the substrate with nitrous oxide to remove the fluoride residue.

Abstract: Disclosed is a semiconductor device and a method for fabricating such semiconductor device, specifically a High Electron Mobility Transistor (HEMT) with a back barrier layer for blocking electron leakage and improve threshold voltage. In one embodiment, a semiconductor device, includes: a Gallium Nitride (GaN) layer; a front barrier layer over the GaN layer; a source electrode, a drain electrode and a gate electrode formed over the front barrier layer; a 2-Dimensional Electron Gas (2-DEG) in the GaN layer at a first interface between the GaN layer and the front barrier layer; and a back barrier layer in the GaN layer, wherein the back barrier layer comprises Aluminum Nitride (AlN).

Abstract: Strain relief trenches may be formed in a substrate prior to growth of an epitaxial layer on the substrate. The trenches may reduce the stresses and strains on the epitaxial layer that occur during the epitaxial growth process due to differences in material properties (e.g., lattice mismatches, differences in thermal expansion coefficients, and/or the like) between the epitaxial layer material and the substrate material. The stress and strain relief provided by the trenches may reduce or eliminate cracks and/or other types of defects in the epitaxial layer and the substrate, may reduce and/or eliminate bowing and warping of the substrate, may reduce breakage of the substrate, and/or the like. This may increase the center-to-edge quality of the epitaxial layer, may permit epitaxial layers to be grown on larger substrates, and/or the like.

Abstract: Structures and methods for controlling dopant diffusion and activation are disclosed. In one example, a semiconductor structure is disclosed. The semiconductor structure includes: a channel layer; a barrier layer over the channel layer; a gate electrode over the barrier layer; and a doped layer formed between the barrier layer and the gate electrode. The doped layer includes (a) an interface layer in contact with the barrier layer and (b) a main layer between the interface layer and the gate electrode. The doped layer comprises a dopant whose doping concentration in the interface layer is lower than that in the main layer.