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Background & Objective: Stroke-associated pneumonia (SAP) is a common complication of ischemic stroke, increasing the length of hospital stay and costs, and affecting prognosis. This study aimed to determine the incidence of SAP, investigate the risk factors that lead to SAP to facilitate a more targeted response to the prevention of SAP. Methods: A retrospective study was performed to analyze the factors that predict SAP in an acute stroke population from a university affiliated hospital in Fujian, China. A SAP risk score table was constructed. Results: A total of 1,016 patients with acute cerebral infarction were enrolled. The incidence of SAP was 13.58%. Multivariate regression analysis found that age, NIHSS, GCS scores, dysphagia, heart failure, creatinine, and proton pump inhibitors (PPIs) use were independently associated with SAP. Based on the data, a SAP risk score table was constructed with age > 75 years -2 points, NIHSS ≥ 16 -2 points, GCS score ≤ 8 -1.5 points, dysphagia - 5 points, heart failure - 1.5 points, creatinine - 1 point, PPIs use - 1.5 points, a total of 14.5 points. The optimal value was 3 points. Conclusions: Age, NIHSS, GCS score, dysphagia, heart failure, creatinine, and PPIs use were predictive of SAP.

Context Re-yan-ning mixture (RYNM) is a new national drug approved by China's State Food and Drug Administration for the treatment of colds, simple pneumonia and acute bronchitis. Objective To determine the mechanism of action of RYNM in the treatment of bacterial pneumonia. Materials and methods Using the network pharmacology approach, the multiple components, component candidate targets and multiple therapeutic targets of RYNM were screened and functionally enriched. Also, we established a rat Streptococcus pneumonia model to verify the results of network pharmacology enrichment analysis. Forty male SPF Sprague Dawley rats were divided into four groups of 10 rats: control (normal saline), model (normal saline), levofloxacin-intervened and RYNM-intervened groups. IL-10, NOS2, COX-1, IL-6, TNF-α and NF-κB in serum and BALF were detected by ELISA. Western blot detected IL-17, IL-6, TNF-α, COX-2 and Bcl-2. Results The network pharmacology approach successfully identified 48 bioactive components in RYNM, and 65 potential targets and 138 signal pathways involved in the treatment of Streptococcus pneumonia with RYNM. The in vivo experiments indicated that model group has visible inflammation and lesions while RYNM and levofloxacin groups have not. The RYNM exhibited its therapeutic effects on Streptococcus pneumonia mainly via the regulation of cell proliferation and survival through the IL-6/IL-10/IL-17, Bax/Bcl-2, COX-1/COX-2, NF-κB and TNF-α signalling pathways. Discussion and conclusions The present study demonstrated the protective effects of RYNM on Streptococcus pneumonia, providing a potential mechanism for the treatment of bacterial pneumonia with RYNM.

Near infrared spectra (NIR) technology is a widespread detection method with high signal to noise ratio (SNR) while has poor modeling interpretation due to the overlapped features. Alternatively, mid-infrared spectra (MIR) technology demonstrates more chemical features and gives a better explanation of the model. Yet, it has the defects of low SNR. With the purpose of developing a model with plenty of characteristics as well as with higher SNR, NIR and MIR technologies are combined to perform high-level fusion strategy for quantitative analysis. A novel chemometrical method named as Mahalanobis distance weighted (MDW) is proposed to integrate NIR and MIR techniques comprehensively. Mahalanobis distance (MD) based on the principle of spectral similarity is obtained to calculate the weight of each sample. Specifically, the weight is assigned to the inverse ratio of the corresponding MD. Besides, the proposed MDW method is applied to NIR and MIR spectra of active ingredients in deltamethrin and emamectin benzoate formulations for quantitative analysis. As a consequence, the overall results show that the MDW method is promising with noticeable improvement of predictive performance than individual methods when executing high-level fusion for quantitative analysis.

Integrated optrodes for optogenetics have been becoming a significant tool in neuroscience through the combination of offering accurate stimulation to target cells and recording biological signals simultaneously. This makes it not just be widely used in neuroscience researches, but also have a great potential to be employed in future treatments in clinical neurological diseases. To optimize the integrated optrodes, this paper aimed to investigate the influence of surface material and illumination upon the performance of the microelectrode/electrolyte interface and build a corresponding evaluation system. In this work, an integrated planar optrode with a blue LED and microelectrodes was designed and fabricated. The charge transfer mechanism on the interface was theoretically modeled and experimentally verified. An evaluation system for assessing microelectrodes was also built up. Using this system, the proposed model of various biocompatible surface materials on microelectrodes was further investigated under different illumination conditions. The influence of illumination on the microelectrode/electrolyte interface was the cause of optical artifacts, which interfere the biological signal recording. It was found that surface materials had a great effect on the charge transfer capacity, electrical stability and recoverability, photostability, and especially optical artifacts. The metal with better charge transfer capacity and electrical stability is highly possible to have a better performance on the optical artifacts, regardless of its electrical recoverability and photostability under the illumination conditions of optogenetics. Among the five metals used in our investigation, iridium served as the best surface material for the proposed integrated optrodes. Thus, optimizing the surface material for optrodes could reduce optical interference, enhance the quality of the neural signal recording for optogenetics, and thus help to advance the research in neuroscience.

variable selection is critical to select characteristic variables of critical quality attributes to improve model performance and interpret the identified variables in multivariate calibration. However, classical variable selection methods were developed and optimized by the prediction error. It is rare for the robustness evaluation of variable selection methods. In this study, the robustness of four different variable selection methods was investigated by adding different types of simulate noises to validation set and calibration and validation sets, respectively. The reproducibility as well as root mean squared error of prediction (RMSEP) were used together as common measure in assessing the robustness of different variable selection methods. The robustness of four variable selection methods method was investigated using two near infrared (NIR) datasets including open-source dataset of corn and Chinese herbal medicine (CHM) dataset. The result illustrated that variable importance in projection (VIP) was substantially more robust to additive noise, with smaller RMSEP value and high reproducibility. This provides a novel strategy for the reliability evaluation of variable selection methods in NIR model of critical quality attributes.

Process quality control is essential for the manufacturing of Chinese Materia Medica. Non-destructive monitoring is still a challenge for the quality control of Chinese Materia Medica manufacturing. As the commonly used non-destructive process analysis technology, near infrared spectroscopy, near infrared chemical imaging, and laser-induced breakdown spectroscopy have been applied to the quality control of Chinese Materia Medica manufacturing. The characteristic near infrared bands of 29 natural chemical components have been assigned. Ten spectral pre-processing methods and five variable selection methods have been optimized, respectively. Given the interrelationship among modeling parameters, a system modeling concept was put forward to establish a global model. Accuracy Profile was further proposed as the validation method of models. In addition, the homogeneity of chlorpheniramine maleate tablets from six brands was successfully visualized by near infrared-chemical imaging. As and Hg variation in An-Gong-Niu-Huang Wan have been rapidly monitored by laser-induced breakdown spectroscopy. A systematic modeling method (model establishment, evaluation, and validation) and the non-destructive technology of homogeneity visualization and toxic element detection have been developed for quality control of Chinese Materia Medica manufacturing, which is shown in Figure 1 of the article. These achievements have greatly promoted the research and application of process analysis technology in Chinese Materia Medica manufacturing, laying a solid foundation for the development of intelligent Chinese pharmaceutical industry.

In0.17Ga0.83N-based metal-semiconductor-metal photo-diodes (MSM-PDs) with recessed anode electrodes were fabricated and characterized. The photodiodes exhibited low dark current of $8\,\times \, 10^{-12}$ A at 5 V, which was one order lower than that of the conventional planar MSM-PDs. Peak responsivity up to 0.22 A/W was obtained at 430 nm and 1.5 V, corresponding to an external quantum efficiency of 63%. The 440 nm/490 nm rejection ratios of the recessed and planar MSM-PDs were ~103 and 102, respectively. The improvements were attributed to the suppression of lateral surface leakage current and the enhancement of the internal electric field by the recessed anode electrodes.

Crystal quality improvements of AlN epilayers grown on sapphire substrates has been achieved by using periodically pulsed-trimethylgallium (TMGa) flows (PTFs) in the initial growth stage of high-temperature AlN. The 400-nm-thick AlN layer deposited with this method demonstrated atomically flat surface, and the line widths of x-ray rocking curves were 40 and 245 arcsec for (002) and (105) reflections, respectively. GaN mole fraction was measured to be less than 0.6% in the AlN layer, indicating a surfactant effect of the PTFs. A combination of experimental characterizations and density functional theory calculations unveils that the improvements are ascribed to the supplement of Ga atoms and the enhanced surface migration of Al adatoms by using the PTFs which promotes the transition of growth mode from three-dimension to two-dimension one.

We reported the selective area growth (SAG) of semipolar { 11 2 2 } InGaN/GaN multiple quantum wells (MQWs) laser diodes (LDs) on the patterned GaN/AlN/Si (111) templates. For GaN (0001) on Si (111), the natural cleavage planes of GaN { 1 1 00 } and Si { 11 2 } are aligned. In this work, the templates were patterned with stripe windows oriented along GaN [ 1 1 00 ] direction. Utilizing a two-step SAG method, the semipolar GaN-based laser structures were successfully deposited on the inclined { 11 2 2 } facets of the laser stripes. STEM measurements indicated the upper areas of inclined { 11 2 2 } facets are nearly defect free due to the bending effect of TDs. The cavity facets were produced by cleaving method. Stimulated emission was achieved under optical pumping at room temperature, showing a threshold pump power density of 1.85 MW/cm2, which was attributed to the low defect and small internal field on the upper areas of semipolar { 11 2 2 } facets selectively grown on the Si (111) substrates.

With the rapid development of visual inspection technology, computer technology, and image processing technology, machine vision technology has become more and more mature, and the role of quality inspection and control in the steel industry is becoming more and more obvious and important. Defects on the surface of the strip are a key factor affecting the quality inspection process. Its inspection plays an extremely important role in improving the final quality. For a long time, traditional manual inspection methods cannot meet actual production needs, so in-depth research on steel surface defect inspection systems has become the consensus of today’s steel companies. The accuracy and low performance of traditional detection methods can no longer meet the needs of people and society. The surface defect detection method based on machine vision has the characteristics of high accuracy, fast processing speed, and intelligent processing, which is the main trend of surface defect detection. We select a steel plate; take the invariant moment features of the cracks, holes, scratches, oil stains, and other images on it; extract the data results; and analyze them. Then, we read the texture features of these defect images again, extract the data results, and analyze them. The experimental results prove that after the mean value filter and Gaussian filter process the image, the mean variance value MSE is relatively large ( 46.276 > 31.2271 ), and as the concentration of salt and pepper noise increases, the rate of increase of MSE increases obviously, and as the peak signal-to-noise ratio and the mean variance value MSE increase continuously ( 32.2271 < 33.3695 ), the image distortion is more serious. The method designed in this paper is extremely effective. Improving the surface quality of steel is of great significance to improving market competitiveness.

Micropyramid vertical GaN-based ultraviolet (UV) light-emitting diodes (LEDs) on Si(111) substrate have been fabricated by selective area growth to reduce threading dislocations and the polarization effects. There is no-light emission at the bottom and six planes of the pyramid at lower current due to the leakage current and nonradiative recombination of the dislocation at the bottom and the 90° threading dislocations (TDs) at six planes of the pyramid, and the top of the pyramid is the high-brightness region. The micropyramid UV LED has a high optical output intensity under a small current injection, and the series resistance of unit area is only a quarter of the conventional vertical LEDs, so the micropyramid UV LED would have a high output power under the drive circuit. The reverse leakage current of a single micropyramid UV LED is 2 nA at −10 V.

In this work, the groove depth of the vertical GaN trench MOSFETs have been investigated by TCAD simulation. The groove depth is found to have a crucial influence on the specific on-resistance and breakdown voltage. A deep enough groove is required to annihilate the build-in barrier between the p-body and the n-drift region close to the sidewall of the groove, in order to reduce the specific on-resistance. On the other hand, an increased groove depth will also cause electrical field peak and hence degrade the breakdown voltage. Therefore, there is a trade-off between the specific on-resistance and breakdown voltage, and optimization is required. This study has provided a quantitative analysis on the optimization scheme.

InGaN/GaN multiple quantum wells (MQWs) were selectively grown on patterned GaN/AlN/Si (111) templates with periodic stripe openings separated by large SiO2 covered spacing. In comparison with the conventional epitaxial lateral overgrowth, the migration behaviours of group-III adatoms on the large mask region has a distinct effect on the structural and optical properties of InGaN/GaN MQWs selectively grown on the narrow stripe openings. In order to control them, a wide stripe window nearby the narrow one was adopted to modulate the local growth environments in our experiment. Flat and faceted InGaN/GaN MQWs stripes with trapezoidal cross section composed of basal (0001) plane and two semipolar { 11 2 2 } facets were obtained. The optical properties were investigated by the microscopic photoluminescence (micro-PL) measurement. The difference in emission peak positions observed by scanning the excitation laser across the stripes is related to the surface migration behaviour of the group-III adatoms on the SiO2 masks.

Introduction Leptinʼs role in bone formation has been reported, however, its mechanism of affecting bone metabolism is remaining unclear. In this study, we aimed to test whether leptin has a positive effect on fracture healing through the possible mechanism of increasing vascular endothelial growth factor (VEGF) expression in callus tissue. Methods Standardized femur fractures were created in leptin-deficient ob/ob and wildtype C57BL/6J mice, and recombinant mouse leptin or its vehicle (physiological saline) was administered intraperitoneally during the study. Body weight, radiological, histologic and immunoblotting analyses were performed at different stages of fracture healing. Key findings The results showed that leptin treatment led to lower rate of body weight change in both mice genotypes. Radiological and histological analyses showed that the experimental groups had better fracture healing at 14, 21 and 28 days compared to the control groups. Leptin-treated groups had significantly higher VEGF expression in callus compared with the control groups at 2 and 3 weeks post-fracture except normal mice at 2 weeks, and leptin-deficient mice had higher VEGF levels in calluses than normal mice at the same timepoint. Conclusion Low-dose systemically-administered leptin has a positive effect on promoting fracture healing during the latter stages in a clinically-relevant mouse bone fracture model, and increase callus VEGF levels.

The uniform distribution model of the surface donor states in AlGaN/GaN heterostructures has been widely used in the theoretical calculation. A common and a triple-channel AlGaN/GaN heterostructure Schottky barrier diodes have been fabricated to verify the models, but the calculation results show the uniform distribution model can not provide enough electrons to form three separate 2DEGs in the triple-channel AlGaN/GaN heterostructure. Our experiments indicate the uniform distribution model is not quite right, especially for the multiple-channel AlGaN/GaN heterostructures. Besides, it is found the exponential distribution model possibly matches the actual distribution of the surface donor states better, which allows the 2DEG to form in each channel structure during the calculation. The exponential distribution model would be helpful in the research field.

We report an abnormal phenomenon that the source-drain current (I D) of AlGaN/GaN heterostructure devices decreases under visible light irradiation. When the incident light wavelength is 390 nm, the photon energy is less than the band gaps of GaN and AlGaN whereas it can causes an increase of I D. Based on the UV light irradiation, a decrease of I D can still be observed when turning on the visible light. We speculate that this abnormal phenomenon is related to the surface barrier height, the unionized donor-like surface states below the surface Fermi level and the ionized donor-like surface states above the surface Fermi level. For visible light, its photon energy is less than the surface barrier height of the AlGaN layer. The electrons bound in the donor-like surface states below the Fermi level are excited and trapped by the ionized donor-like surface states between the Fermi level and the conduction band of AlGaN. The electrons trapped in ionized donor-like surface states show a long relaxation time, and the newly ionized donor-like surface states below the surface Fermi level are filled with electrons from the two-dimensional electron gas (2DEG) channel at AlGaN/GaN interface, which causes the decrease of I D. For the UV light, when its photon energy is larger than the surface barrier height of the AlGaN layer, electrons in the donor-like surface states below the Fermi level are excited to the conduction band and then drift into the 2DEG channel quickly, which cause the increase of I D.

The cutoff frequency of Schottky barrier diode (SBD) depends on its junction capacitance and series resistance. The two-dimensional electron gas (2DEG) at AlGaN/GaN interface has high carrier mobility and carrier concentration. However, AlGaN/GaN heterostructure SBD usually shows a high series resistance because of the thin 2DEG channel. In this work, multiple AlGaN/GaN heterojunctions are vertically stacked for forming multiple parallel 2DEG channels to reduce the series resistance. Multi-channel AlGaN/GaN-based air-bridge structure planar SBDs with a half through-hole are demonstrated. The series resistance of quintuple-channel SBD is only 39.5% of the single-channel SBD's. Moreover, a low capacitance is obtained by the Schottky electrode with a half through-hole structure. The low series resistance and the low capacitance contribute to a 16 GHz cutoff frequency in millimeter-wave band.

Combining the p-NiO gate electrode and the stack barrier structure with unintentionally doped GaN insertion layer (serves as etching termination layer) is promising for achieving normally-off GaN power device. The band alignment and band offsets at the interface of NiO and GaN insertion layer play a crucial role in determining the performance of GaN device. In this letter, the p-NiO thin film/unintentionally doped GaN heterojunction was fabricated through a simple thermal oxidation method. The p-NiO thin film presents face-centered cubic crystalline structure with a band gap of approximately 3.69 eV. The interfacial band alignment of the heterojunction is characterized by X-ray photoelectron spectroscopy. Based on core-level binding energies and valence band maximum values, the valence and the conduction band offsets were determined to be 1.16 eV and 1.45 eV, respectively. The NiO/GaN heterojunction is concluded to be type-II staggered band configuration.

p-type NiO films were prepared at different oxidizing temperatures in O 2 ambient for normally-off AlGaN/GaN HFETs application. The crystalline structure, electrical properties and band gap of NiO films are dependent upon temperatures. Compared with the conventional Ni-gated HFETs, NiO-gated HFETs present positively shifted threshold voltage and smaller gate leakage current, while the drain current density shows slightly degradation. Combining the recess structure and NiO gate, normally-off GaN HFETs was achieved with a threshold voltage of approximately 0.5 V. The band diagram of the NiO/AlGaN/GaN structure demonstrates that the p-type conductivity and large conduction band offset between NiO and GaN cause the lift-up potential, which result in 2DEG depletion and positive threshold voltage shift.

The electric properties of Pt Schottky contacts on semipolar r-plane and polar c-plane of GaN micro truncated-pyramid are compared. The Schottky diodes of the inclined r-plane sample illustrate a relatively inferior rectified performance than that of the top c-plane GaN in term of the lower Schottky barrier heights, larger ideality factor and reverse leakage current. By depositing Pt metal on the dislocation-free area of the top of GaN micro pyramid, the Schottky performance of r-plane GaN can be slightly improved, but still shows much larger reverse leakage current than that of c-plane GaN. It is found that polarization-related surface states and incorporation of donor impurities, rather than dislocation, should mainly contribute to this remarkable electric discrepancy of the planes.

In this paper, a normally off Al2O3/AlN/GaN MISFET on Si substrate for achieving high threshold voltage stability and uniformity is obtained based on selective area growth. A thin AlN space layer (SL, ~1 nm) is adopted to GaN-based template, and the AlGaN/GaN het-erostructureis selectivelygrownon the template to naturally form a recessed structure. By insertion of the AlN SL, the Al2O3/AlN/GaN interface trapping and scattering effects are effectively suppressed. As a result, a low threshold voltage hysteresis ( $\Delta {V}_{\mathrm{ th}}$ , 80 mV at maximum gate sweep voltage of 10 V by dc ${I}$ – ${V}$ measurement and smaller than 200 mV in linear region by pulse ${I}$ – ${V}$ measurement) and a high peak field-effect mobility ( $\mu _{\sf FE})$ of 192 cm2/ $\text{V}\cdot \text{s}$ are obtained in Al2O3/AlN/GaN MISFET. It is a significant improvement compared with Al2O3/GaN MISFET without AlN SL. The Al2O3/AlN/GaN MISFET also exhibits a maximum drain current ( ${I}_{d,max})$ of 620 mA/mm, a low on-resistance ( ${R}_{\rm {ds}, \mathrm{\scriptscriptstyle ON}})$ of $9.6~\Omega \cdot $ mm, and a high uniformity of ${V}_{\mathrm{ th}}$ (2.5 ± 0.1 V).

BACKGROUND The aim of this study was to explore the value of the ratio of mitral peak filling velocity (E) to mitral annular velocity (e') in early diastole as a predictor of coronary artery disease (CAD). MATERIAL AND METHODS The study population consisted of 83 consecutive patients (aged 38-77 years, 22 women and 61 men) who received coronary angiography. The E/e' ratio was estimated by echocardiographic examination. Statistical significance was determined by receiver operating characteristic (ROC) curve and multiple logistic regression analyses. RESULTS ROC curve analysis showed that the optimal E/e' ratio cut-off for predicting CAD was 8.153 with a specificity of 72.4% and sensitivity of 57.4%. The area under the ROC curve was 0.635 with a 95% confidence interval (CI) for normal distribution of 0.515-0.755 (p=0.043). Multivariate logistic regression analysis demonstrated that the E/e' ratio was closely associated with CAD (odds ratio [OR], 1.350; 95% CI, 1.087-1.676, p=0.007). CONCLUSIONS The E/e' ratio is a simple and practical predictor of CAD and may be an independent risk factor for CAD. Large-cohort and multi-center studies are required to confirm these observations.

New sensor technologies play an important role in quality evaluation of Chinese materia medica (CMM) and include near-infrared spectroscopy, chemical imaging, electronic nose and electronic tongue. This review on quality evaluation of CMM and the application of the new sensors in this assessment is based on studies from 2010 to 2015, with prospects and opportunities for future research., Graphical abstract New sensor technologies play an important role in quality evaluation of Chinese materia medica (CMM) and include near-infrared spectroscopy, chemical imaging, electronic nose and electronic tongue. This review on quality evaluation of CMM and the application of the new sensors in this assessment is based on studies from 2010 to 2015, with prospects and opportunities for future research.fx1

Objective Leukoaraiosis (LA), as an age‐related white matter degeneration, is mainly caused by chronic ischemia. Our study aims to explore the efficacy of different doses of atorvastatin (ATV) in the vascular endothelial function in patients with LA. Methods Our study enrolled 402 LA patients who were then randomly included as control or treated with ATV (10 mg), ATV (20 mg), or ATV (30 mg). The total cholesterol (TC), triglycerides (TG), high‐density lipoprotein cholesterol (HDL‐C), and low‐density lipoprotein cholesterol (LDL‐C) were detected by enzyme colorimetric assay. The high‐sensitivity C‐reactive protein (hs‐CRP) level, reactive hyperemia index (RHI), endothelin‐1 (ET‐1) content, and nitric oxide (NO) level were tested by latex agglutination test, peripheral arterial tonometry technology, radioimmunoassay, and nitrate reductase assay, respectively. Results After 8 weeks of ATV treatment, the levels of TC, LDL‐C, and HS‐CRP decreased significantly, and the trends were demonstrated in a more significant way with the increases of dose of ATV. The treatment with ATV at different doses elevated NO level and RHI and declined ET‐1 content. Gastrointestinal reaction, muscular pain, and increased aminopherase were observed after treatment with the ATV at different doses with more obvious symptoms detected accompanied by the increase of the dose. The RHI was in negative correlation with the ET‐1 and HS‐CRP while in positive correlation with NO. Conclusion Our study demonstrates that ATV can significantly improve the vascular endothelial function in LA patients with a dose‐dependent effect.

In this study, convolutional neural networks (CNN) strategy combined with mid-infrared (MIR) spectra is applied for sugar adulteration identification in honey. In order to acquire the variations from different classes as well as obtain a better interpretation of the model, a visualization of the CNN algorithm is employed for honey adulteration determination. All kernels are co-acted to explore subtle features by learning different weights and biases. The amplified or attenuated signals transformed by the kernels yield positive or negative effects to the model. Furthermore, the visualized features are implemented for spectroscopy interpretation. The overall results demonstrate that CNN is a promising method with improved accuracy over least squares support vector machines (LS-SVM) and partial least squares discriminant analysis (PLS-DA) especially for the market-obtained samples. Besides, this study supports the theoretical and practical foundation for CNN on the aspects of feature selection, visualization and model interpretation.

Crack-free thin film InGaN/GaN multiple quantum wells light-emitting diodes (LEDs) were successfully transferred from 2-in Si (1 1 1) growth substrate onto a thin epoxy resin carrier. The good chemical corrosion resistance of epoxy resin simplifies the protective processes during silicon substrate wet-chemical etching. The Raman spectra measurement shows an obvious relaxation of tensile strain after the LEDs structure transferred to epoxy resin carrier. Combining with a metal reflector deposition after silicon removed, the thin-film LEDs on epoxy resin carrier show significant improvement in comparison with the conventional LEDs on silicon. The operating voltage at 350 mA decreases from 4.95 to 4.5 V and the series resistance decreases from 3.1 to 2.6 Ω. Light output shows an increase of 92% after the LEDs transferred to epoxy resin carrier.

The selective area growth (SAG) technique has been proved to be an effective method to achieve trench gate normally-off AlGaN/GaN MOSFET. In this paper, the two-dimensional electron gas (2DEG) transport properties of SAG AlGaN/GaN heterostructure are investigated for samples with different insertion layers. As the thickness of the GaN insertion layer increases, the mobility of 2DEG drops at first and then increases dramatically. This is explained by a shift of the location of the 2DEG from the GaN template into the GaN insertion layer. Interface contamination at the template/insertion layer interface is found to be the reason of the degradation of the transport properties. Through optimizing the thickness of the SAG GaN insertion layer, 2DEG mobility is similar to the value of as-grown AlGaN/GaN heterostructure. The proper thickness of SAG GaN insertion layer for device fabrication is 24 nm referring to the variation in 2DEG transport properties.

Al-doped ZnO (AZO) thin films with resistivity of 6.6 × 10−4 Ω cm were prepared by introducing H2 in DC magnetron sputtering atmosphere. The Hall Effect measurement demonstrates that a part of the hydrogen atoms act as shallow donors while others act as neutral scattering impurities. Only proper H2 partial pressure decreases the resistivity to the lowest value. The properties of SiNx free crystalline Si (c-Si) solar cells were improved when AZO thin films were applied. The films served as both anti-reflection (AR) coatings and front electrode assistance. Ensuring an outstanding AR effect and a low sheet resistance, the thickness of the films was optimized in order to reduce the optical absorption, and thus effectively increase the short circuit current density (Jsc). The influence of the films versus different Ag fingers and emitter sheet resistance was investigated. The results showed that the Jsc was improved apparently (at least by 0.7 mA/cm2), while the fill factor was enhanced obviously from 62 to 70 % and from 73 to 75 %, respectively, which depended on the initial series resistance.

The influence of different AlGaN Impurity Blocking Layer (IBL) thickness in the GaN/Si (111) structure with GaN/AlN SLs buffer on the material and electrical properties of GaN/Si (111) system was studied in detail. It is found that the insertion of AlGaN IBL can increase the (102) FWHM and decrease the (002) FWHM. Meanwhile, AlGaN IBL with an optimized thickness can further improve the surface roughness and strain-state of GaN-Si (111) system. By using Secondary Ion Mass Spectroscopy, it is found that AlGaN IBL have a strong effect in blocking the Si donor impurities originating from the Si substrate during the high temperature growth, which can decrease the leakage current while the breakdown voltage can be dramatically increased.

The quality of safflower (Carthamus tinctorius L.) in the market is uneven due to the problems of dyeing and adulteration of safflower, and there is no perfect standard for the classification of quality grade of safflower at present. In this study, computer vision (CV) and near-infrared (NIR) were combined to realize the rapid and nondestructive analysis of safflower. First, the partial least squares discrimination analysis (PLS-DA) model was used to qualitatively identify the dyed safflower from 150 samples. Then the partial least squares (PLS) model was used for quantitative analysis of the hydroxy safflower yellow pigment A (HSYA) and water extract of undyed safflower. Herein, the discrimination rate of PLS-DA model reached 100%, and the residual predictive deviation (RPD) values of the PLS models for HSYA and water extract were 2.5046 and 5.6195, respectively. It indicated that the rapid analysis method combining CV and NIR was reliable, and its results can provide important reference for the formulation of safflower quality classification standards in the market.

We experimentally evaluated the interface state density of GaN MIS-HEMTs during time-dependent dielectric breakdown (TDDB). Under a high forward gate bias stress, newly increased traps generate both at the SiN x /AlGaN interface and the SiN x bulk, resulting in the voltage shift and the increase of the voltage hysteresis. When prolonging the stress duration, the defects density generated in the SiN x dielectric becomes dominating, which drastically increases the gate leakage current and causes the catastrophic failure. After recovery by UV light illumination, the negative shift in threshold voltage (compared with the fresh one) confirms the accumulation of positive charge at the SiN x /AlGaN interface and/or in SiN x bulk, which is possibly ascribed to the broken bonds after long-term stress. These results experimentally confirm the role of defects in the TDDB of GaN-based MIS-HEMTs.

The capacitance and the series resistance are two main factors which determine the cut-off frequency of Schottky barrier diodes (SBDs) for their application in millimeter-wave and terahertz regions. The junction capacitance is closely related to the anode dimension of a SBD. Reducing the anode size can effectively decrease the junction capacitance, but it will increase the series resistance and the difficulty of the device manufacturing process is also increased. In this paper, an AlGaN/GaN based air-bridge structure planar SBD with a half through-hole is investigated. The half through-hole was formed on the center of a circular anode by inductively coupled plasma etching to the unintentional doping-GaN channel layer. The capacitance formed by the anode metal and the two-dimensional electron gas at the AlGaN/GaN interface is effectively reduced under the condition of holding the metal area of anode. The total capacitance of the 20 μm-radius anode SBD with a 19.95 μm-radius half through-hole dramatically decreases from 2.32 pF of the device without the half through-hole to 21.5 fF. In addition, since the current is mainly distributed at the edge of the circular anode, the series resistance is only slightly increased. The cut-off frequency of the air-bridge planar SBD with a 20 μm-radius anode and a 19.95 μm-radius half through-hole was 114.1 GHz. To reduce the size of the anode and optimize the ohmic contact, the cut-off frequency could be further improved.

The effect of high overdrive voltage on the positive bias temperature instability (PBTI) trapping behavior is investigated for GaN metal–insulator–semiconductor high electron mobility transistor (MIS-HEMT) with LPCVD-SiN x gate dielectric. A higher overdrive voltage is more effective to accelerate the electrons trapping process, resulting in a unique trapping behavior, i.e., a larger threshold voltage shift with a weaker time dependence and a weaker temperature dependence. Combining the degradation of electrical parameters with the frequency–conductance measurements, the unique trapping behavior is ascribed to the defect energy profile inside the gate dielectric changing with stress time, new interface/border traps with a broad distribution above the channel Fermi level are introduced by high overdrive voltage.

Partially AlGaN recessed scheme based on selective area growth was experimentally demonstrated to improve the performance of normally-off GaN MISFET. The damage-free thin AlGaN barrier layer with lower Al-content in recessed region contributes to a positive V th shift compared with the reference one (from 1.8 V to 2.5 V). At the same time this method realizes a high peak μκΣ of 2033 cm2/V·s and a low gate channel sheet resistance of 519 Ω/□ (@V g = 12 V), which is a significant improvement compared with the fully recessed-gate device. The higher Al-contents AlGaN barrier layer regrown in accessed region is adopted to maintain high-conductivity 2DEG transport property. As a result, a maximum drain current of 645 mA/mm and a low on-resistance of 6.8 Ω-mni are obtained. The GaN MISFET also exhibits a low hysteresis, low gate leakage and slight current collapse. This technique could fabricate very promising normally-off GaN devices by designing thickness and Al-content of the controllable-growth thin AlGaN barrier layer.

Based on the engineering backgrounds of the damaged bridge, a bridge-onbridge method is proposed to reinforce the damaged bridge in this paper. To carry the temporary overload vehicle, the structural type and support of the Prefabricated Highway Steel Bridge is designed. Then, the three-dimension numerical model is built and the numerical simulations are conducted to investigate the feasibility of the design.

To investigate the plasma drag force acting on the droplet in gas metal arc welding (GMAW), we used a high-speed photography system to image the metal transfer process, and proposed a method employing particle dynamics to measure the plasma drag force. Experimental results of the droplet diameter, mass, acceleration, plasma drag force and gravity acting on the droplet are presented. The results indicate that, with the increase of welding current, the droplet diameter, mass and gravity decrease, the droplet acceleration and plasma pressure increase, while the plasma drag force and the gravity acting on the droplet decrease. Moreover, we find that the plasma drag force is 10 and near 100 times the gravity acting on the droplet. The experimental values of plasma drag force and plasma pressure show good agreement with the theoretical value by fluid theory; their order of magnitudes are 10−4 N and 103 Pa, respectively, which demonstrates that it is an effective method to analyze the plasma drag force of welding arc. Keywords: Plasma drag force, High-speed photography, Gas metal arc welding, Droplet transfer, Particle dynamics

Oxidized iridium (Ir) was employed as the Schottky contact of In0.18Ga0.82N photodiodes. The Schottky barrier height (SBH) increases from 0.70 eV for the as-deposited Ir contacts to 0.91 eV for the contacts annealed at 500 ° C in O2 ambient, while the dark current at −3 V bias decreases from $4.65\times 10^{\mathrm {-5}}$ to $2.29\times 10^{\mathrm {-9}}$ A. A zero-bias responsivity of 32 mA/W was obtained at 410 nm in the devices with the oxidized contacts, corresponding to an external quantum efficiency of 10%. Analysis results indicate that the increased SBH and decreased leakage current can be mainly ascribed to two factors: 1) the higher work function of the IrO2 contacts formed by oxidation annealing and 2) the reduction in the background electron concentration near the IrO2/In0.18Ga0.82N interface caused by the generation of compensating group-III vacancies during the oxidation process. Besides, the oxidation of group-III elements may also play a minor role in the performance improvement.

In this paper, the selective area growth (SAG) technique is used to regrow thin AlGaN/GaN heterostructure on access region for realizing trench gate normally-off AlGaN/GaN MOSFET. Heavy background doping is found in SAG AlGaN/GaN heterostructure, which is not expected for its degradation on device performance. The background doping originates from SiO2 residuals at SAG interface. Through reducing the deposition temperature of SiO2 mask, background doping can be efficiently suppressed. As a result, the 2 dimensional electron gas transport property of SAG AlGaN/GaN heterostructure improves greatly, which is as good as the as-grown AlGaN/GaN heterostructure. Moreover, the performance of normally-off SAG AlGaN/GaN MOSFET improves greatly by suppression the Si residual on GaN template.

We demonstrated the fabrication of GaN nanowire (NW) by selective etching of the GaN micro truncated-pyramid (μ-TP) in KOH solution. The GaN μ-TP, which consists of a (0 0 0 1) Ga-polar top surface and six {1 1 ¯ 0 1} N-polar sidewalls, were grown on the patterned AlN/Si template in metal organic chemical vapor deposition (MOCVD) system. KOH solution can selectively etch the N-polar sidewalls while leave the Ga-polar top surface intact. Hexagonal-prism-structured GaN NW with (0 0 0 1) top surface and {1 1 ¯ 0 0} sidewalls was obtained after adequate chemical etching. It was found that the three-dimensional geometry of the GaN NW is determined by the diameter of the (0 0 0 1) top surface and the height of the GaN μ-TP. And the chemical etching mechanism of GaN μ-TP towards GaN NW in hydroxide solution was explained.

Display Omitted Surface morphologies were roughened without the use of masks.Surface morphologies were optimized by varying Cl2 concentration.Surface morphologies were optimized by adjusting RF bias power.Light output of surface-roughened LEDs was enhanced by 43.2%. In the present paper, the surface of GaN-based light-emitting diodes (LEDs) was roughened by inductively coupled plasma reactive ion etching (ICP-RIE) system. Without the utilization of etching mask, the roughened surface morphologies were optimized by varying Cl2 concentration in Cl2/BCl3/N2 mixing gas and adjusting RF bias power parameters of the ICP system. There was no obvious degradation of electrical properties of surface-roughened LEDs after the ICP dry etching process. Furthermore, the light output power of surface-roughened LEDs was enhanced by 43.2%, compared with conventional LEDs.

Near-infrared chemical imaging (NIR-CI) is an emerging technology that combines traditional near-infrared spectroscopy with chemical imaging. Therefore, NIR-CI can extract spectral information from pharmaceutical products and simultaneously visualize the spatial distribution of chemical components. The rapid and non-destructive features of NIR-CI make it an attractive process analytical technology (PAT) for identifying and monitoring critical control parameters during the pharmaceutical manufacturing process. This review mainly focuses on the pharmaceutical applications of NIR-CI in each unit operation during the manufacturing processes, from the Western solid dosage forms to the Chinese materia medica preparations. Finally, future applications of chemical imaging in the pharmaceutical industry are discussed.

Electrically driven single-pyramid InGaN/GaN micro light-emitting diode ( $\mu$ -LED) on silicon substrate has been fabricated and investigated. The $\mu$ -LED exhibits a typical p-n diode behavior with a turn-on voltage of 2.5 V and realizes an efficient electroluminescence (EL) under an ultra-small injection current (3 $\mu$ A). An excellent EL pattern with a high-brightness spot at apex, a hexagonal blue ring around the base of pyramid, and six bright spots at the corners of pyramid base was observed. EL wavelength centered at about 450 nm, and a slight peak shift was found as the injection current increased from 100 to 1000 $\mu$ A. The small magnitude of spectral shift is attributed to the growth of multiple quantum wells on semi-polar GaN pyramid side facets and its accompanied reduction of the quantum-confined Stark effect. The $\mu$ -LED has the promising potential for applying in micro display and electrically driven single photon emitter.

To deal with heterogeneous classification problem efficiently, each heterogeneous object was represented by a set of measurements obtained on different part of it, and the heterogeneous classification problem was reformulated in the framework of multi-instance learning (MIL). Based on a variant of count-based MIL assumption, a maximum count least squares support vector machine (maxc-LS-SVM) learning algorithm was developed. The algorithm was tested on a set of toy datasets. It was found that maxc-LS-SVM inherits all the sound characters of both LS-SVM and MIL framework. A comparison study between the proposed approach and the other two MIL approaches (i.e., mi-SVM and MI-SVM) was performed on a real wolfberry fruit spectral dataset. The results demonstrate that by formulating the heterogeneous classification problem as a MIL one, the heterogeneous classification problem can be solved by the proposed maxc-LS-SVM algorithm effectively.

Quality by design (QbD) has become an inevitable trend because of its benefits for product quality and process understanding. Trials have been conducted using QbD in nanosystems' optimization. This paper reviews the application of QbD for processing nanosystems and summarizes the application procedure. It provides prospective guidelines for future investigations that apply QbD to nanosystem manufacturing processes. Employing the QbD concept in this way is a novel area in nanosystem quality.

With a Ni/SiO 2 /Au/SiN x compound function layer, in-situ localized surface plasmon of gold nano-particles on the top of multiple quantum wells nanorods was fabricated, whose integrated photoluminescence intensity show a 1.9-fold enhancement compared with bare nanorods.

Objective Rapid discrimination of three classes of safflowers, dyed safflower, adulterated safflower, and pure safflower using computer vision and image processing algorithms. Methods A low cost computer vision system (CVS) was designed to measure the color of safflowers in the RGB (red, green, blue), L∗a∗b∗, and HSV (hue, saturation, vale) color spaces. The color moments in these three color spaces were extracted from the acquired images as color features of safflower. In addition, five kinds of pigments that are commonly used to dye safflowers were identified by high-performance liquid chromatography as a reference. Pattern recognition methods were investigated for rapid discrimination, including an unsupervised principal component analysis (PCA) algorithm and a supervised partial least squares discriminant analysis (PLS-DA) algorithm. Results The mean error ( e ¯ ) between color values measured with the colorimeter and calculated with the CVS was 2.4%, with a high correlation coefficient (r) of 0.9905. This result indicated that the established CVS was reliable for color estimation of safflowers. The PLS-DA model, which had a total accuracy of 91.89%, outperformed the PCA model in classifying pure, adulterated, and dyed safflowers. Conclusion The color objectification is a promising tool for rapid identification of dyed and adulterated safflowers.

In this paper, crack-free InGaN/GaN multiple quantum wells (MQWs) light-emitting diodes (LEDs) were transferred from Si (111) substrate onto the electroplating Cu submount, with inserting a 5-pair TiO $_{2}$ /SiO $_{2}$ omnidirectional reflector (ODR) and an Al mirror, defined as TiO $_{2}$ /SiO $_{2}$ –Al ODR. The reflectivity in the blue spectral range of the TiO $_{2}$ /SiO $_{2}$ –Al ODR was as high as 97%. The current–voltage (I–V) characteristics showed no obvious degradation of electrical properties for the ODR-based LED on Cu. In comparison to conventional LEDs on Si without ODRs, the light output of ODR-based LEDs on Cu was enhanced by 59.3% at a driving current of 350 mA. The improvement is mainly attributed to the following factors: the removal of the opaque Si substrate, the inserting of the high-reflectivity TiO $_{2}$ /SiO $_{2}$ –Al ODR, and the transfer onto the Cu submount with better thermal conductivity.

We investigated the influences of periodic Si δ-doping on the characteristics of n-GaN grown on Si (111) substrate by metal organic chemical vapor deposition (MOCVD). By using periodic δ-doping, the tensile stress in GaN film induced by Si-doping was reduced to 0.057 GPa/10 18 cm −3 electrons, which was 56% smaller than that in uniformly doped GaN. Moreover, superior electrical properties were achieved in periodic δ-doped GaN films without cracks by varying the Si doping level. X-ray diffraction measurements show similar 002 and 102 full widths at half maximum (FWHMs) for periodic δ-doped GaN and uniformly doped GaN with the same Si doping amount, implying equivalent crystalline qualities of GaN:Si through the two doping methods. A narrower FWHM of the near band edge emission of GaN was obtained in the photoluminescence spectrum with periodic δ-doping, indicating enhanced optical properties.