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In the flexible photovoltaic (PV) industry, increment of the metal‐organic chemical vapor deposition (MOCVD) deposition zone is crucial to reducing the cost of ownership and increasing the power conversion efficiency (PCE). This implies that the larger closed coupled showerhead (CCS) of MOCVD system should be used in the manufacture of flexible gallium arsenide (GaAs) PV thin‐film solar cells. Currently, Aixtron Crius II is the largest commercial CCS reactor for GaAs deposition with 55 × 2 inches circular wafers. As the size of the carrier and showerhead increases, the deposition uniformity and gas flow stability become more difficult to control. To address these issues, previous studies have investigated the effects of geometric and process parameters of MOCVD on the vertical process gas inlet, with either a rotating carrier model represented by Veeco using high‐speed rotating carrier (Turbo Disc), and Aixtron using low‐speed rotating planetary carrier, or a horizontal process gas injector with a rotating carrier. However, these efforts have limited further capacity scale‐up. In this study, numerical simulations and fluid visualization experiments are conducted, based on previous research on thermal uniformity, for design optimization of a gas distribution system in a large square GaAs‐MOCVD reactor. The achieved reactor capacity is 36 × 4 inches square wafers in one process cycle, and the optimal average deposition rate and deposition uniformity of GaAs film are ≈0.430 µm min−1 and 0.93%, respectively. [ABSTRACT FROM AUTHOR]

Metal additive manufacturing (AM) has the advantages of novel part morphology, new material property, and short production cycle, attracting significant attention in automobile, aerospace, and other fields. Nevertheless, the repeatability and stability of part quality are difficult to guarantee in the current metal AM process, hindering the development of metal AM technology. Vital process variables such as molten pool characteristics, spatter characteristics, surface morphology, and radiation temperature are directly related to the quality of parts. Monitoring the dynamic changes vital variables is critical. Image processing techniques such as image transformation, recognition, segmentation, and enhancement are introduced to obtain manufacturing process information through processing and analyzing rich image features. The monitoring system's processing results are usually collected in real time to help solve the repeatability and stability problems of the metal AM process. Presently, in situ and real-time monitoring methods are the most popular, and unfortunately, the literature lacks a comprehensive report. Thus, this paper thoroughly describes in situ and real-time process monitoring on the basis of image processing for metal AM. This paper reviews the in situ and real-time monitoring on the basis of traditional image processing to analyze monitoring objects, process classifications, and image processing carriers. Then, the advantages and disadvantages of in situ and real-time monitoring of metal AM based on artificial intelligence are discussed and compared. Finally, image processing algorithm generalization, quality, small samples, and image labeling problems are analyzed and discussed. A technical route for metal AM real-time feedback control is proposed by combining image processing with other technologies. [ABSTRACT FROM AUTHOR]

During the process of growing diamond crystals via microwave plasma chemical vapor deposition (MPCVD), the substrate temperature will gradually increase with increasing growth time. At present, the commonly used method to compensate for the temperature increase is to reduce the deposition parameters (gas pressure and input power) or adjust the height of the susceptor. However, according to previous studies, reducing the substrate parameters will reduce the growth rate. In addition, adjusting the height of the susceptor may cause secondary plasma, which could damage the equipment. Therefore, it is necessary to find the reason for the substrate temperature increase with the growth time and eliminate it. Firstly, the effect of substrate size change on the substrate temperature was simulated dynamically, which indicated that the substrate size change was not the main reason for the continuous increase of the substrate temperature. Subsequent analysis showed that non‐diamond carbon formed at the bottom of the grown diamond, which may cause a change of the thermal contact resistance. Therefore, a thermal contact resistance component was introduced into the existing model of diamond growth, and it was found that the substrate temperature increased with the roughness of the bottom of the substrate. In order to eliminate the influence of thermal contact resistance, a welding growth method was proposed with the aim of avoiding the accumulation of the non‐diamond carbon at the bottom of the substrate. The growth with different welding materials showed that the grown diamond's internal stress distribution after welding growth was similar to that without welding growth, but the non‐diamond carbon at the bottom was obviously restrained. However, the selection of welding materials needs to be further optimized with respect to the welding stability and growth rate. [ABSTRACT FROM AUTHOR]

The nitrogen-vacancy (NV) center is a point defect in the diamond, which can be used as a quantum sensor or emitter. It must maintain a negative charge state to utilize its electronic and optical properties. However, enhancing the negative charge stability and avoiding becoming the "dark state" have been challenges in many situations. In this study, we introduced phosphorus atoms as donor elements to provide extra electrons to the NV center to keep its negative charge state through theoretical simulation. We used density functional theory to investigate the electronic and optical properties of the NV center with phosphorus donors in different configurations. We confirmed that the NV center with phosphorus donor could retain its original properties required as a quantum bit. Moreover, in the non-local excitation processes, both in the one-photon and two-photon approaches, including the intersystem crossing (ISC) process, the NV center with phosphorus donor could have a higher resistance to charge conversion (from NV− to NV0) and the "photo-blinking" phenomenon than the NV center with nitrogen donor. Thus, our results suggest that phosphorus can be a promising donor element for improving the stability and functionality of the NV center in quantum applications. [Display omitted] [ABSTRACT FROM AUTHOR]

Surface functionalization of diamonds is an important topic for the negatively charged nitrogen-vacancy (NV−) center based quantum sensors. We investigate the electronic properties of oxidized diamond (111) surfaces and their effects on the NV− centers using the density of functional theory. The results show that the epoxy oxidized diamond (111) surface has neither surface spin noises nor inter-bandgap states and also has a positive electron affinity (1.85 eV) with nearly 99% preferential alignment of nitrogen-vacancy, indicating the epoxy oxidized (111) surface could be a perfect host of the NV− centers. Additionally, we make further examinations by placing an NV− center ∼1 nm from the epoxy oxidized (111) surface. The results indicate that the epoxy oxidized (111) surface has no obvious effects on the defect levels and optical transitions of the single NV− center. To the best our knowledge, the epoxy oxidized (111)-(2 × 1) surface may be the first diamond surface that not only theoretically satisfies the electronic requirements of shallow NV− centers but can also be fabricated through the oxidization process. Therefore, the epoxy oxidized diamond (111)-(2 × 1) surface is the most promising candidate to be applied in NV-based quantum sensors. Image 1 [ABSTRACT FROM AUTHOR]

Background and Purpose: Skeletal muscle is the predominant site for glucose disposal and fatty acid consumption. Emerging evidence indicates that the crosstalk between adipose tissue and skeletal muscle is critical in maintaining insulin sensitivity and lipid homeostasis. The current study was designed to investigate whether myricanol improves insulin sensitivity and alleviates adiposity through modulating skeletal muscle-adipose tissue crosstalk.Experimental Approach: The therapeutic effect of myricanol was evaluated on palmitic acid (PA)-treated C2C12 myotubes and high-fat diet (HFD)-fed mice. The crosstalk between myotubes and adipocytes was evaluated using Transwell assay. The cellular lipid content was examined by Nile red staining. The mitochondrial content was assessed by MitoTracker Green staining and citrate synthase activity, and the mitochondrial function was examined by Seahorse assay. Expression of mitochondria-related and insulin signalling pathway proteins was analysed by Western blot, and the irisin level was determined by elisa kit.Key Results: Myricanol increased mitochondrial quantity and function through activating AMP-activated protein kinase, resulting in reduced lipid accumulation and enhanced insulin-stimulated glucose uptake, in PA-treated C2C12 myotubes. Furthermore, myricanol stimulated irisin production and secretion from myotubes to reduce lipid content in 3T3-L1 adipocytes. In HFD-fed mice, myricanol treatment alleviated adiposity and insulin resistance through enhancing lipid utilization and irisin production in skeletal muscle and inducing browning of inguinal fat.Conclusions and Implications: Myricanol modulates skeletal muscle-adipose tissue crosstalk, to stimulate browning of adipose tissue and improve insulin sensitivity in skeletal muscle. Myricanol might be a potential candidate for treating insulin resistance and obesity. [ABSTRACT FROM AUTHOR]

Highlights • P–H complex has the lowest energy when H occupies the AB site. • P–H complex is most stable when P is doped within the second C layers. • P–H complex is less likely to form in (1 1 1) surface than in (0 0 1) surface. Abstract Although phosphorus is an n-type donor in diamond, H impurities can bind to and passivate P. Here, H binding to a P dopant in both diamond (0 0 1) and (1 1 1) surfaces is investigated by density functional theory. The energy calculations reveal the most stable P–H complex structures for each P-doped position. P–H binding energies are the lowest for the second P doped C layer among those for four investigated P-doped C layers. H migration from on-surface to P in the second C layer is exothermic, with an energy barrier of zero, whereas that from on-surface to P below the second C layer is endothermic, with an energy barrier greater than 0.95–7.09 eV. Thus, both of binding energy and migration calculations imply that P–H complex is more likely to form when P is doped in the second C layer than when P is doped below the second C layer. Moreover, H migration energy barrier from on-surface to P below the second C layer in the (1 1 1) surface is at least 0.85 eV greater than that in the (0 0 1) surface, which indicates that P–H complex is less likely to form in (1 1 1) surface than in (0 0 1) surface. [ABSTRACT FROM AUTHOR]

Highlights • Myricanol from the barks of Chinese bayberry was identified as an AMPK activator. • Myricanol inhibited adipogenesis in the initial stage of adipocytes differentiation. • Myricanol induced lipolysis and lipid oxidation in 3T3-L1 adipocytes. • Myricanol improved insulin sensitivity in mature adipocytes. • Myricanol attenuated lipid accumulation in high-fat diet-fed zebrafish. Abstract Myricanol is a diarylheptanoid isolated from Chinese bayberry. Through virtual docking strategy, myricanol was discovered as an AMP-activated protein kinase (AMPK) activator among a series of structural analogs, with high affinity for the γ subunit of AMPK. Myricanol was also evaluated for regulatory effects on lipid accumulation and insulin sensitivity in 3T3-L1 adipocytes and adiposity in high-fat diet-fed zebrafish. Myricanol suppressed lipid accumulation in 3T3-L1 cells in the initial stage (days 0–2) by suppressing adipogenesis and in the terminal stage (days 4–7) by inducing lipolysis and lipid combustion through activating AMPK. Moreover, myricanol enhanced insulin-stimulated glucose uptake by activating the insulin signaling pathway. In high-fat diet-fed zebrafish, myricanol inhibited lipid accumulation by suppressing adipogenic factors including peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer binding protein α (C/EBPα). In summary, the results indicate that myricanol could be a potential therapeutic agent against obesity by activating the AMPK signaling pathway. [ABSTRACT FROM AUTHOR]

Alkaloids represent a large family of natural products with diverse structures and bioactivities. These compounds and their derivatives have been widely used in clinics to treat various diseases. The endophytic Aspergillus is a filamentous fungus renowned for its extraordinary ability to produce active natural products of high therapeutic value and economic importance. This review is the first to focus on Aspergillus-derived alkaloids. Through an extensive literature review and data analysis, 263 alkaloids are categorized according to their structural features into those containing cytochalasans, diketopiperazine alkaloids, quinazoline alkaloids, quinoline alkaloids, indole alkaloids, pyrrolidine alkaloids, and others. These metabolites exhibited diverse biological activities, such as antibacterial activity, cytotoxicity, anti-inflammatory activity, and α-glucosidase, ACE, and DPPH inhibitory activities. The bioactivity, structural diversity, and occurrence of these alkaloids are reviewed in detail. [ABSTRACT FROM AUTHOR]

This study investigated the effect of four typical facial expressions (calmness, happiness, sadness and surprise) on contact characteristics between an N95 filtering facepiece respirator and a headform. The respirator model comprised two layers (an inner layer and an outer layer) and a nose clip. The headform model was comprised of a skin layer, a fatty tissue layer embedded with eight muscles, and a skull layer. Four typical facial expressions were generated by the coordinated contraction of four facial muscles. After that, the distribution of the contact pressure on the headform, as well as the contact area, were calculated. Results demonstrated that the nasal clip could help make the respirator move closer to the nose bridge while causing facial discomfort. Moreover, contact areas varied with different facial expressions, and facial expressions significantly altered contact pressures at different key areas, which may result in leakage. [ABSTRACT FROM AUTHOR]

The equipment and technological processes used in manufacturing electronic products are gradually being automated and networked. Currently, digital twin technology continues to evolve and mature. The electronics manufacturing industry is undergoing an intelligent and digital transformation. Micro-electro-mechanical system (MEMS) sensors have been widely used in the automotive field due to their small size, low cost, and high reliability. In this study, a new intelligent production line for automotive MEMS pressure sensors driven by digital twin is individually designed. The intelligent production line system consists of physical production lines, digital production lines, twin data, and data service systems. The technology of multi-source heterogeneous data acquisition is used to process and analyze data collected in real time in a physical production line. Based on the technology of parallel control, the physical and digital production lines are synchronized. To obtain optimal process parameters, a process database is established through the analysis of the key processes of the production line. Three types of automotive MEMS pressure sensors are successfully manufactured in the constructed digital twin-driven intelligent production line. The intelligent production line can realize 24-h unattended operation. The product yield is above 98 %, and the takt time is less than 16 s. [ABSTRACT FROM AUTHOR]

Fibrous media is the most common method of filtration, which is generally characterized by its pressure drop and filtration efficiency. In this work, the computational fluid dynamics (CFD) technology was applied to simulate the filtration performance of multi–fiber filters. The pressure drop and filtration efficiency with different fiber arrangements, fiber diameters, face velocities and particle sizes were studied. It was found that filtration efficiency changed with the face velocity for different particle sizes. The layered structures with the same fiber diameters and total solid volume fraction (SVF) were compared, indicating that the dense–sparse structure had the highest filtration efficiency for all the simulated particle sizes at the cost of high pressure drop. Then the dense–sparse structure was optimized to achieve a better filtration performance by using less tiny fibers in the front–row and removing some fibers in the back–row. [ABSTRACT FROM AUTHOR]

This work proposes a novel structure design of active slider with a piezoelectric actuator at the top of the slider body and a soft layer between the substrate and head elements, to efficiently control the flying height of slider. A parametric simulation was performed to obtain an optimize dimension of PZT actuator and the most efficient soft material. Then three types of slider structures were designed and investigated with considering air bearing effects to achieve large actuation efficiency. [ABSTRACT FROM AUTHOR]

It has been reported that high corticosterone level could damage the normal hippocampal neurons both in vitro and in vivo. Furthermore, high concentration of corticosterone induced impair in PC12 cells has been widely used as in vitro model to screen neuroprotective agents. Cajaninstilbene acid (CSA), a natural stilbene isolated from Cajanus cajan leaves, has various activities. In present study, we investigated the effect of CSA on corticosterone-induced cell apoptosis and explored its possible signaling pathways in PC12 cells. We demonstrated that pretreatment with CSA at the concentrations of 1–8 μmol/L remarkably reduced the cytotoxicity induced by 200 μmol/L of corticosterone in PC12 cells by MTT, and further confirmed the neuroprotection by Hoechst 33342 and PI double staining and lactate dehydrogenase release (LDH) assay at the concentration of 8 μmol/L. Moreover, the cytoprotection of CSA was proved to be associated with the homeostasis of intracellular Ca 2+ , relieving corticosterone-induced oxidative stress by decreasing the contents of ROS and malondialdehyde (MDA), increasing the activities of superoxide dismutase (SOD) and catalase (CAT), and the stabilization of ER stress via down-regulating the expression of ER chaperone protein glucose-regulated protein 78 (GRP78), ER stress associated transcription factor C/EBP homologous protein (CHOP/GADD153), and the X box-binding protein-1 (XBP-1), as well as the expression of ER stress-specific protein caspase-12 and its downstream protein caspase-9. Considering all the findings, it is suggested that the neuroprotective activity of CSA against the impairment induced by corticosterone in PC12 cells was through the inhibition of oxidative stress and ER stress-mediated pathway. [ABSTRACT FROM AUTHOR]

In this paper, a heater-slit design was investigated to reduce the crosstalk effects of thermal track positioning control (TPC) heating on the thermal flying height control, using a coupling thermal-structural simulation and air-bearing simulation. The results show that the slit design helps to achieve a large head displacement along crosstrack direction and flying height reduction at head elements, due to the reduction of the mechanical constraints on the thermally induced expansion of the slider body. The undesirable flying height reduction at side edge of trailing pad of the slider can be improved by further optimization of slit design. Thus, the heater-slit design overcomes the limitation on the air-bearing surface design for TPC slider. [ABSTRACT FROM AUTHOR]

Ultrasonic motors (USMs) are novel electric motors used for positioning controls. Due to the drive characteristic of USMs, wear and fatigue of friction material at the contact friction interface are inevitable. Contact deformation can cause local damage of USMs. Therefore, obtaining the details of the stress distribution due to the inelastic deformation is important. In this paper, a contact model of traveling wave ultrasonic motor (TWUSM) is proposed. A three-dimensional finite element model with cohesive zone elements embedded between friction layer and rotor is then developed. Infinite finite elements are included in this modeling as the boundary condition. The evolution of deformation in friction layer and rotor due to the mechanical surface loading is presented. The possible interfacial delamination process between friction material and rotor is also numerically investigated. [ABSTRACT FROM PUBLISHER]

In this work, we propose a novel thermal flying height control (TFC) slider, by designing a slit near the thermal heater in the slider. Design of the slit can reduce the mechanical constraints on the head elements and concentrate the heat around head elements. In turn, head elements can achieve more thermal protrusion and flying height reduction compared to the traditional TFC slider. The simulation results show that the application of the slit achieves a flying height reduction of 1.4 nm at writer and 1.7 nm at reader. Parametric study indicates that a trade off among the slit thickness ( a), the distance of the slit to ABS ( d) and thermal heater ( t) should be optimized to achieve both large flying height reduction and small difference of flying height between reader and writer. [ABSTRACT FROM AUTHOR]

In this work, we propose a novel thermal actuator by designing a thermal insulator, a thermal conductor, and their combination to the traditional thermal heater. The thermal-structure simulation coupled with air bearing simulation is used to simulate the actuation by the thermal actuator, as well as the effects on flying performance of slider being actuated. The simulation results show that an additional 0.8-1.1 nm flying height reduction can be obtained by applying the proposed thermal actuator when the flying height of TFC slider is about several nanometers. [ABSTRACT FROM AUTHOR]

• This paper first applies EI-TOF to the additive manufacturing process. • This paper is the first to monitor atmospheric composition during the L-DED process. • The degree of variation of the gases significantly changed with the laser power. Laser-based Directed Energy Deposition (L-DED) is a promising additive manufacturing technology, which has broad application prospects and practical value in many fields. The nondestructive testing technology of L-DED work piece quality monitoring requires high accuracy and capability for real-time process. This work developed an online monitoring system based on a miniature electron impact ion source time-of-flight mass spectrometer (EI-TOF) and a high-speed camera, which monitored the atmosphere above the molten pool area. The number of spatters was measured using a high-speed camera. The composition of the samples and spatters was measured by using element analyzer, inductively coupled plasma mass spectrometry, and electron spectroscopy. The variation in the atmosphere was measured using EI-TOF, and the results confirmed that the O 2 , N 2 and H 2 O content decreased during the L-DED process. At the laser power of 400 W, the oxygen consumptions were 92.5% and 86.4% compared with those at the laser power of 500 W and 600 W, respectively. During the L-DED process, the number of spatters decreased when the laser power was increased from 400 W to 600 W. And at the laser power of 600 W, the average number of spatters was reduced to 59.3% compared with the laser power of 400 W. It can be found that dust contained a large amount of virgin powder and little spatters. It also can be found that at the laser power of 400 W, 500 W and 600 W, the amount of oxygen in the dust was 0.544%, 0.242% and 0.159%, respectively. The relative content of oxygen in the cross section of the seam was 35.58%, 43.79% and 44.30%, respectively. The deviation of the monitoring results (H 2 O, N 2 , O 2) are significant at the same power when different materials was used as the substrate. [ABSTRACT FROM AUTHOR]

In the pursuit of high areal recording density towards 10 Tb/in^2, it is necessary to improve the positioning accuracy of the magnetic head in the hard disk drive head-positioning control system. Ultrasonic motors are novel electric motors well used in positioning control. Contact stresses can exist in the friction material and rotor. Obtaining the details of the stress distribution due to the inelastic deformation is important. A contact model of traveling wave ultrasonic motor (TWUSM) is proposed. A 2-D finite element model between stator and friction material is then developed. The evolution of deformation in friction material and rotor due to the mechanical surface loading is presented. [ABSTRACT FROM PUBLISHER]

The piezoelectric flying height control slider has recently been implemented in magnetic recording disk drives to reduce the flying height. This paper performs the electromechanical simulation and air-bearing simulation to investigate the effects of the shear-model deformation on the static flying attitude of PZT slider. The location of PZT sheet and air bearing surface of slider are investigated to achieve a low flying height and robust head-disk interface. The results show that a short distance of the PZT sheet to the trailing edge of the slider can help to achieve a low flying height. A small center-trailing pad of the slider can also help to achieve a low flying height, but cannot prevent the reduction in pitch angle. The depth of the center-trailing pad does not change the reduction ratio of the pitch angle when increasing the drive voltage. A big pitch angle value is needed to avoid the pitch angle falling below zero at a high drive voltage. [ABSTRACT FROM AUTHOR]

This work investigates the piezoelectric contact sensor in the thermal flying height control (TFC) slider. A finite element model is built for the thermal flying height control slider with a piezoelectric contact sensor, which is used to detect the contact between the slider and disk. A constant force is applied at the maximum thermal protrusion point of air bearing surface. The simulation results show that the ZnO sensor with shear-mode is more sensitive to contact force than that with transverse-mode. The sensitivity of contact sensor can be increased by reducing the cross-sectional area of sensor, increasing the thickness of sensor, and choosing a short distance of sensor to air bearing surface. In addition, the thermal-stress effects from TFC heater on contact sensor are significantly large and the amplitude of thermal-stress inducing output voltage is orders larger than that induced by contact force. However, by optimizing the distance of sensor to ABS, it is possible to eliminate the thermal-stress effects. Finally, the response time of thermal-stress induced electrical voltage of contact sensor is about 0.3 ms. [ABSTRACT FROM AUTHOR]

Artemisinin and its derivatives are the most effective antimalarial drugs. Besides anti-malarial activity, artemisinin and its derivatives have displayed wide-spectrum bioactivities such as anti-parasite, anti-tumor, and anti-obesity effects. Obesity is an epidemic worldwide which is a big threat to human health, but there are only a few approved anti-obesity drugs in the world. Also, these drugs are efficient to limited patients partly because their safety and efficacy are questioned. Anti-inflammatory therapies may be valuable in obesity treatment since growing evidence shows chronic metabolic inflammation is implicated in metabolic disease pathogenesis. As artemisinin and its derivatives display effective anti-inflammatory and immunoregulatory properties with less toxicity, it provides an insight for novel drug development in obesity therapeutic strategies via immune-regulatory mechanisms. In this review, the potential of artemisinin and its derivatives to treat various metabolic diseases such as obesity and diabetes is discussed. [ABSTRACT FROM AUTHOR]

Perillyl alcohol (POH), a natural monoterpene, exhibits potent anticancer activity and may also play a role in inhibiting plant pathogens. However, its mechanism of action on controlling gray mold of tomato remains unclear. In this study, we investigated the effect of POH on Botrytis cinerea infected tomato. The results demonstrate that POH inhibits the in vitro growth of B. cinerea by disrupting plasma membrane integrity, thereby exhibiting broad-spectrum antimicrobial activity. Metabolomic analysis revealed that POH activated jasmonic acid (JA) biosynthesis and induced JA production in B. cinerea -treated tomato. Furthermore, POH upregulated the expression of defense-related genes and induced ROS accumulation. Specifically, POH induced the accumulation of kaempferol in tomato and exogenous kaempferol disrupted the plasma membrane of B. cinerea and induced ROS production. Taken together, POH can inhibit the development of gray mold, besides enhancing plant immunity against B. cinerea by inducing JA accumulation and promoting kaempferol biosynthesis. • POH activates jasmonic acid biosynthesis and induces JA production. • POH upregulates the expression of resistance genes and induces ROS accumulation. • Kaempferol exhibits antimicrobial activity against B. cinerea. [ABSTRACT FROM AUTHOR]

• A new in-situ monitoring system was proposed to upscale resolution and extract geometric characteristics during AM process. • The proposed ViTSR performs better than the SOTA methods in terms of PSNR, which may reduce the cost of high-speed camera. • The molten pool and plasma arc can be simultaneously and accurately extracted by FCN with input of reconstructed frames. • The low-cost AI edge board reduces the inference time of ViTSR to 50.97 ms, which reduce the cost of computing in AM process. In additive manufacturing (AM), in-situ monitoring systems are vital for ensuring process quality. However, the widespread adoption of traditional high-speed camera-based monitoring systems is hindered by the prohibitively high cost of the required high-speed cameras. This paper introduces an innovative low-cost in-situ monitoring system that utilizes AI edge computing boards to expedite digital image processing without requiring high resolution (HR) video sequences. The system integrates a visual transformer-based video super resolution (ViTSR) network for reconstructing high resolution video frames and employs a fully convolutional network (FCN) to extract geometric characteristics of the molten pool and plasma arc simultaneously during AM processes. Comparing ViTSR with six state-of-the-art super-resolution methods, it achieved the highest peak signal-to-noise ratio (PSNR) of 38.16 dB on the test data. Moreover, the FCN utilized the reconstruction results from ViTSR, demonstrating an accuracy of 96.34% in multi-object extraction tasks. Through operator fusion and model pruning, the inference time of ViTSR and FCN on the AI edge board is optimized to 50.97 ms and 67.86 ms, respectively. Consequently, the proposed system achieves a total inference time of 118.83 ms, meeting the real-time quality monitoring needs of AM processes. Furthermore, this approach effectively reduces the expenses associated with high-speed camera-based monitoring systems, thereby promoting the widespread adoption of in-situ monitoring systems within the realm of AM. [ABSTRACT FROM AUTHOR]

Malaria continues to pose a serious global health threat, and artemisinin remains the core drug for global malaria control. However, the situation of malaria resistance has become increasingly severe due to the emergence and spread of artemisinin resistance. In recent years, significant progress has been made in understanding the mechanism of action (MoA) of artemisinin. Prior research on the MoA of artemisinin mainly focused on covalently bound targets that are alkylated by artemisinin‐free radicals. However, less attention has been given to the reversible noncovalent binding targets, and there is a paucity of information regarding artemisinin targets at different life cycle stages of the parasite. In this study, we identified the protein targets of artemisinin at different stages of the parasite's intraerythrocytic developmental cycle using a photoaffinity probe. Our findings demonstrate that artemisinin interacts with parasite proteins in vivo through both covalent and noncovalent modes. Extensive mechanistic studies were then conducted by integrating target validation, phenotypic studies, and untargeted metabolomics. The results suggest that protein synthesis, glycolysis, and oxidative homeostasis are critically involved in the antimalarial activities of artemisinin. In summary, this study provides fresh insights into the mechanisms underlying artemisinin's antimalarial effects and its protein targets. Highlights: We identified the targets of artemisinin at different stages of the intraerythrocytic cycle of Plasmodium falciparum using a photoaffinity probe of artemisinin.Artemisinin can interact with parasite proteins in vivo through both covalent and noncovalent mechanisms.Artemisinin may exert its antimalarial effects by interfering with the parasite's protein synthesis, glycolysis, and oxidative homeostasis pathways.This study provides fresh insights into the mechanisms underlying artemisinin's antimalarial effects and its protein targets. [ABSTRACT FROM AUTHOR]

Background: Increasing attention has been given to the search for neuroprotective ingredients from natural plants. Myrica rubra bark (MRB) has been used in traditional oriental medicine for over thousand years and has potential neuroprotection. Methods and Results: Ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) was used to identify the compounds in MRB extract, and the MTT assay was performed to evaluate the neuroprotection of six major compounds from MRB against glutamate-induced damage in PC12 cells. The result displayed nineteen compounds were identified, and myricitrin and myricanol 11-sulfate were shown to have neuroprotection, which prevented cell apoptosis through alleviating oxidative stress by reducing the levels of reactive oxygen species and methane dicarboxylic aldehyde, as well as by enhancing the activities of superoxide dismutase. Conclusions: Several active compounds from MRB may offer neuroprotection and have the potential for the development of new drugs against central nervous system diseases. [ABSTRACT FROM AUTHOR]

• A method of 3D reconstruction for LPBF parts by light field camera is proposed. • Simple and high-precision calibration is achieved by the consistency method. • A LFEPI-Unet is designed for accuracy disparity reconstruction. • Accurately mapping of disparity, depth, and 3D spatial coordinates is established. • First-time application for in situ 3D reconstruction and monitoring of LPBF parts. The assessment of output quality in the laser powder bed fusion process entails the analysis of the three-dimensional morphology of the manufactured parts, which plays a crucial role in quality control to prevent metallurgical defects. This study proposes a novel approach of three-dimensional reconstruction for laser powder bed fusion parts using a light field camera. Initially, a consistency method for high-precision camera calibration was explored to determine the virtual camera pixel size and coefficient of effective focal length of light field camera. Subsequently, the model based light field epipolar-plane image Unet is designed to obtain disparity information without any data augmentation techniques. By leveraging both binocular and light field optical paths, a robust mapping relationship of the disparity, depth, and visually coherent three-dimensional contour was established. Finally, the three-dimensional contours of laser powder bed fusion parts were reconstructed by the established mapping with a single exposure of the light field camera. The proposed method enables three-dimensional contour visualization of laser powder bed fusion parts from multi-view perspectives, which facilitates in situ monitoring of the spattering distance, three-dimensional spatial points and lines of the printed layers and contours of printed parts. With a calibration error of 50 μm and resolution of 180 μm for the light field camera (Lytro illum camera), the maximum relative and absolute errors between reconstructed three-dimensional spatial points were 4.33 % and 260 μm respectively when compared with theoretical dimension, and 0.5 % and 210 μm respectively when compared with manufactured dimension. The maximum root-mean-square error of reconstructed three-dimensional contour surfaces was found to be 1.55 mm. This study represents the first application of a light field camera for in situ three-dimensional reconstruction of laser powder bed fusion parts, which notably can be obtained from only a single round of calibration and exposure, enabling seamless monitoring of their surface morphology and facilitating online quality control. These advancements have vast potential for enhancing high-end additive manufacturing. [ABSTRACT FROM AUTHOR]

• LSP was applied on the 50CrVA alloy to improve the mechanical properties. • Propagation characteristic of shock wave was investigated. • Influence of laser energy and spot diameter on residual stress was revealed. • Optimized process parameter and strength enhancement were obtained by LSP. Laser shock peening (LSP) was implemented to treat aircraft landing gear 50CrVA alloy to improve mechanical properties. The sensitivity investigations of time step and mesh size were used to benchmark the 3D finite element method (FEM) model. Based on the established FEM model, the dynamic propagation characteristics of the shock wave inside the sample were predicted. The influence of laser energy and spot diameter on the residual stress field was further investigated. The numerical results indicate that regulating two critical LSP parameters can effectively improve the compressive residual stress (CRS) of metals, and the spot diameter has a greater effect than the laser energy in improving the uniformity of the CRS distribution. After that, the influences of LSP on the CRS field, microstructure, and mechanical properties were experimentally studied. After LSP treatment, the surface CRS reached 494.8 ± 31.8 MPa with an affected depth of about 400 μm. The phase composition was not changed by LSP treatment, but it weakened texture strength and refines grains. Under the impact of grain refinement and CRS, the average surface microhardness of the 50CrVA alloy reached 355 HV, indicating an increase up to 5.3 %. The ultimate tensile strength and yield strength were increased by 11.3 % and 14.5 %, respectively, which were in contrast to the unchanged elongation. This work verifies the feasibility of mechanical properties enhancement of 50CrVA alloy by LSP. [ABSTRACT FROM AUTHOR]

Particle intrusion into the head–disk interface (HDI) is becoming a concern in hard disk drives. Numerical studies of particle movement in HDI are of great importance for reducing particle-induced damage. In this investigation, we study the particle rebound mechanism in HDI. Not only the particle–slider collision but also particle–particle collision models are developed, which are divided into three types, including the collisions of particle and surface (P–S), particle and edge (P–E), and particle and particle (P–P). The subsequent response of particles after the collision, which includes rebound and adhesion, is calculated considering the collisional energy loss. The proposed adhesion/rebound model can more accurately present the particle trajectories in HDI and accumulation on the air bearing surface (ABS). We find that particles are likely to accumulate on the leading rail surfaces of the slider due to the air flow drag and Saffman lift. Considering the adhesion and rebound, particles with a larger diameter are more likely to fly away from the slider after the collision. The existence of particle rebound, to a certain degree, reduces contamination on ABS. [ABSTRACT FROM AUTHOR]

Heat-assisted magnetic recording (HAMR) technology is a great way to achieve higher storage density. In HAMR, dynamic performance of the head–disk interface (HDI) is critically important for the read/write stability. Lubricant bridge formation and lubricant transfer can significantly deteriorate HDI performance. In this paper, a 3-D full-atom model of a slider-lubricant-disk substrate system is established to study the dynamic performance of HDI in HAMR. The overlayers of the slider and disk substrate are made of diamondlike carbon, and the main lubricating ingredient is perfluoropolyether (PFPE). The formation and breaking of the lubricant bridge are investigated with the slider moving up and down. It is found that during the moving down process, PFPE molecules escape from the lubricant layer, and a lubricant bridge between the slider and disk is formed. During the moving up process, the lubricant bridge becomes thin and eventually breaks. The stable value of PFPE weight percentage on the slider during the moving up process is always larger than that during the moving down process. This is because of easier transfer of lubricant molecules to the slider in the low flying height region. The formation height is smaller than the breaking height, but these values are closer when the operational temperature is higher. [ABSTRACT FROM AUTHOR]

This article presents a computational study on contact characteristics of contact pressure and resultant deformation between an N95 filtering facepiece respirator and a newly developed digital headform. The geometry of the headform model is obtained based on computed tomography scanning of a volunteer. The segmentation and reconstruction of the headform model is performed by Mimics v16.0 (Materialise, Leuven, Belgium), which is a medical image processing software. The respirator model is obtained by scanning the surface of a 3M 8210 N95 respirator using a 3D digitizer and then the model is transformed by Geomagic Studio v12.0 (3D system, Rock Hill, SC), a reverse engineering software. The headform model contains a soft tissue layer, a skull layer, and a separate nose. The respirator model contains two layers (an inner face sealing layer and an outer layer) and a nose clip. Both the headform and respirator are modeled as solid elements and are deformable. The commercial software, LS-DYNA (LSTC, Livermore, CA), is used to simulate the contact between the respirator and headform. Contact pressures and resultant deformation of the headform are investigated. Effects of respirator stiffness on contact characteristics are also studied. A Matlab (MathWorks, Natick, MA) program is developed to calculate local gaps between the headform and respirator in the stable wearing state. [ABSTRACT FROM PUBLISHER]

The lateral flow in hard disk drives is greatly disturbed because of the arm swinging rapidly during track seeking, which can greatly affect off-track residual vibrations during track following of the head-gimbal assembly (HGA), as well as the slider. Until now, no simulation studies have been performed to investigate off-track residual vibrations of the HGA that consider lateral flow effects. In this paper, the effect of track-seeking on off-track residual vibrations of the HGA is investigated for air and helium environments using the so-called “fluid dynamic mesh” and the “fluid-structure interaction” methods for the first time. Three different angular acceleration profiles (a square wave, a triangular wave, and a sinusoidal wave) are investigated as a function of seek time (10 and 5 ms). Results show that the smoothening of sharp transitions in the seek profile improves the performance of off-track residual vibrations and shortens the track-following time of the head positioning servo system. In addition, the effect of lateral flow (windage) on off-track residual vibrations must be considered for a square-wave angular acceleration profile. Simulation results show that helium improves the track-following accuracy compared to air because of the lower windage forces acting on the HGA. We observe that the sinusoidal-wave angular acceleration performs best for the three angular acceleration profiles investigated. Furthermore, seek time is found to have only a small effect on off-track residual vibrations during track following. [ABSTRACT FROM PUBLISHER]

Filtering Facepiece Respirator (FFR) is the most common respirator users in the health care environment utilize for personal protection from outside particles. Comfort and fit are important while wearing an FFR. This paper proposes a novel technology to produce customized face seal design for improving the wearing comfort and fit of FFR wearers. In order to customize the design of face seals, we scanned the faces of three subjects using three-dimensional (3D) laser scanning method. A customized face seal for a 3M 8210 N95 FFR for each headform was designed using reverse engineering technique. Next, the face seal prototypes were fabricated with Acrylonitrile Butadiene Styrene (ABS) plastic using the 3D printing method. A force sensing system based on Arduino Uno R3 was developed, and the force sensor of this system was inserted between the FFR and headform to measure contact pressure. Experimental results showed that the newly designed FFR face seal provided the subjects with an improved contact pressure. [ABSTRACT FROM AUTHOR]

An entrapped particle on the slider's air bearing damages the surface of the slider or the disk. The study of particle movement on and the particle adhesion mechanism onto the slider surface is critical to reduce entrapped particle-induced damage. In this paper, we proposed a dynamical model of the adhesive particle's secondary migration on the slider surface. The model predicts whether the adhered particle will remain static by the action of the aerodynamic and adhesion forces. There are three migration movement styles which are rolling, sliding and lifting away from the original adhered location. Further, particle rolling migration behaviors on the slider air bearing surface (ABS) are analyzed considering the effects of flow shear rate, particle diameter and properties. Finally, the particle migration trajectory and velocity with time on the investigated slider are presented. It was found that most particles that adhere to the slider surface remain static for the investigated slider; pure rolling motion on the slider ABS is the main migration styles. The particle with a larger diameter and air shear rate speeds up to a higher velocity, and it takes more time to speed up to the constant velocity. A particle's secondary migration motion can be observed for the particle that adheres to the slider recession region and trailing pad. Then the particle enters airflow blowing out of or rolls away from the head-disk interface. [ABSTRACT FROM AUTHOR]

The complex co-doping structure of boron and sulfur is investigated using the density functional theory approach. Different ratio models show significant differences in electronic properties. More importantly, the interactions of boron, sulfur, and carbon atoms are studied on intrinsic/B-doped (001), (111), and (110) diamond surfaces. The most stable adsorption site, adsorption structure, and charge transfer are discussed. B atom induces a larger adsorption energy (intrinsic: −4.57 eV, −4.56 eV, and −4.00 eV; B-doped: −4.70 eV, −4.72 eV, and −4.86 eV). And a larger charge transfer between diamond and S radicals is also found. Therefore, the phenomenon that the sulfur contents in diamond increases after the introduction of boron in the experiment can be explained. Considering different crystal surfaces, larger adsorption strength is obtained from (111) and (110) surface. And different levels of strain are introduced into three different surfaces. The migration barrier of S atom is also considered. The lowest migration barrier is 0.06 eV on (111) surface, whereas the highest value is found on (001) surface (1.96 eV). B atom also benefits for the H x S radical adsorption. It can be concluded that B doping can help with S and H x S adsorption. This study can provide an explanation for the increased solubility of S on B-doped diamond. [Display omitted] • Theoretical research was conducted on atom interaction mechanism of B, S, and C on three diamond surfaces. • The qualitative explanation was offered for doping property of B-S co-doping by the B and S ratio model (like 2:1). • For the first time, mutual promotion of B and S atoms in doping diamond was explained by simulations. • The migrations of the atom were analyzed with lowest migration barrier (0.06 eV) was discovered. [ABSTRACT FROM AUTHOR]

Although diamond seeds are generally polished before growth, the effect of surface roughness of diamond seeds on crystal growth quality is rarely studied. In this research, three diamond seeds were prepared for researching the effect of surface roughness of diamond seed. They were made by cutting a bulk diamond and subsequently suffered partially polished, totally polished and unpolished, respectively. After a period of microwave plasma chemical vapor deposition growth, various tests were carried out on the samples. According to the microscope and step profiler, the surface roughness of diamond seed did not affect the surface roughness of long-term growth diamonds. Compared by Raman spectra, ultraviolet − visible and infra-red spectra, it indicated that a certain rough surface of diamond seed could improve the internal stress of diamond, but reduce the crystalline quality slightly. Moreover, the surface roughness had almost no impact on the optical properties of the diamond. As a result, diamond seeds with low roughness after cutting could be used for direct growth without polishing, bringing on significant economic for gem-quality diamond production. [ABSTRACT FROM AUTHOR]

In the field of machine learning (ML) and data science, it is meaningful to use the advantages of ML to create reliable interatomic potentials. Deep potential molecular dynamics (DEEPMD) are one of the most useful methods to create interatomic potentials. Among ceramic materials, amorphous silicon nitride (SiNx) features good electrical insulation, abrasion resistance, and mechanical strength, which is widely applied in industries. In our work, a neural network potential (NNP) for SiNx was created based on DEEPMD, and the NNP is confirmed to be applicable to the SiNx model. The tensile tests were simulated to compare the mechanical properties of SiNx with different compositions based on the molecular dynamic method coupled with NNP. Among these SiNx, Si3N4 has the largest elastic modulus (E) and yield stress (σs), showing the desired mechanical strength owing to the largest coordination numbers (CN) and radial distribution function (RDF). The RDFs and CNs decrease with the increase of x; meanwhile, E and σs of SiNx decrease when the proportion of Si increases. It can be concluded that the ratio of nitrogen to silicon can reflect the RDFs and CNs in micro level and macro mechanical properties of SiNx to a large extent. [ABSTRACT FROM AUTHOR]

Currently, heat-assisted magnetic recording (HAMR) technology has been proposed as a method for enabling higher storage density. In this paper, the molecular dynamic simulation method was used to investigate the consumption and recovery of the lubricant perfluoropolyether (PFPE) layer under rapid heating and cooling through HAMR. A full-atom model for the 3-D slider-lubricants-disk substrate system was built for this paper. The lubricant adheres to the diamond-like carbon substrate, and the space between the slider and the lubricant is filled with helium atoms. It is found that HAMR laser heating results in the gradual consumption of the PFPE lubricant, and that the target operational temperature T0 significantly affects the consumption of the PFPE lubricant on the disk substrate. The extent of lubricant consumption increases sharply when T0 is above 600 K. The lubricant’s weight percentage on the disk substrate rises up again when cooling occurs. But it cannot be completely recovered. On the other hand, the bearing pressure reduces the degree of consumption of the PFPE lubricant by laser heating. However, the effect of bearing pressure on the amount of remaining PFPE lubricant becomes weak when T0 is above 800 K. [ABSTRACT FROM AUTHOR]

The lubricant bridge connecting the slider and the disk will significantly deteriorate the read–write stability of the hard disk drive. This paper builds a model of disk-lubricant-slider system. The coarse-grained bead-spring model is used to represent perfluoropolyethers molecules. And the molecular dynamic method is used to study the formation time and the molecule number of the lubricant bridge under different disk rotation speeds and slider flying heights. Furthermore, the influence of lubricant bridge on the pressure acting on the slider pad is also studied. [ABSTRACT FROM AUTHOR]

A numerical method is presented to study the air-flow pattern and particle trajectory in the head–disk interface (HDI) in this paper. It first solves the generalized steady-state Reynolds equation with slip boundary conditions to get the slider attitude. Then, it solves the reduced Navier–Stokes equation to get the air flow velocity distribution in the HDI. The motion equations of particles are solved to obtain the particle trajectory in the HDI by using the fourth-order Runge–Kutta method. Air flow characteristics and particle behaviors are investigated to illustrate the relationship between the air flow and particle trajectory. The effect of the particle release height is also studied. The simulation results show that particle trajectories basically overlap air flow streamlines in the horizontal plane. The particle moves a longer horizontal distance at a lower particle release height. The difference between the horizontal velocity of the particle and the air flow indicates that the Saffman force points to the disk in the transition region close to the leading edges of leading pads. Moreover, the peak values of the air flow vertical velocity in the previously mention location increase with the reduction of the particle release height. And the air flow vertical velocity along the particle trajectory is almost two times larger than that of the particle at the leading edges of leading pads. The results also show that the drag force of the air flow mainly drives particles up toward the air bearing surface at the leading edges of leading pads, but not the Saffman force. [ABSTRACT FROM PUBLISHER]

Heat-assisted magnetic recording (HAMR) is a new approach, which makes the head write data easily under a low magnetic field using a laser to heat the magnetic media to reduce its coercivity, thus, it is considered to be the next generation of higher recording areal density technology. In this paper, a three-dimensional HAMR finite-element model of hard disk drive (HDD) is developed. The temperature distributions around the laser-heating area on disk surface are investigated when the HDD is filled with air and helium. The cooling effects of the disk rotation and the heat convection in head-disk interface (HDI) are also analyzed. [ABSTRACT FROM AUTHOR]

This article presents an improved Filtering Facepiece Respirator (FFR) designed to increase the comfort of wearers during low-moderate work. The improved FFR aims to lower the deadspace temperature and CO2 level by an active ventilation fan. The reversing modeling is used to build the 3D geometric model of this FFR; the Computational Fluid Dynamics (CFD) simulation is then introduced to investigate the flow field. Based on the simulation result, the ventilation fan of the improved FFR can fit the flow field well when placed in the proper blowing orientation; streamlines from this fan show a cup-shape distribution and are perfectly matched to the shape of the FFR and human face when the fan blowing inward. In the deadspace of the improved FFR, the CO2 volume fraction is controlled by the optimized flow field. In addition, an experimental prototype of the improved FFR has been tested to validate the simulation. A wireless temperature sensor is used to detect the temperature variation inside the prototype FFR, deadspace temperature is lowered by 2 K compared to the normal FFR without a fan. An infrared camera (IRC) method is used to elucidate the temperature distribution on the prototype FFR's outside surface and the wearer's face, surface temperature is lowered notably. Both inside and outside temperature results from the simulation are in agreement with experimental results. Therefore, adding an inward-blowing fan on the outer surface of an N95 FFR is a feasible approach to reducing the deadspace CO2 concentration and improve temperature comfort. [ABSTRACT FROM AUTHOR]

An entrapped particle on the slider air bearings damages the surface of the slider or the disk. The study of particle movement on and the particle adhesion mechanism onto the slider surface is critical to reduce entrapped particle-induced damage. This paper investigates the interaction between the particles and slider surface. The particle trajectories in the far-field region are calculated using the classical Runge-Kutta method. In the near-field region, where the distance between the particle and slider surface is less than the mesh size, a new model was applied to predict the particle trajectory and whether the particle will be captured or rebound from the slider surface after the collision. A rebound model was employed to calculate the particle rebound velocity and its corresponding rebound trajectory. It was found that the particle critical velocity for rebound increases as the particle size decreases. The velocity ratio decreases as the incident velocity decreases for the same particle diameter, and it is sensitive to the particle size at a low incident velocity. For the particle collides with and rebounds from the slider surface, the negative rebound velocity makes the particles bounce a small distance away from the pad surface. The force acting on the particles also changes from negative to positive values, and they possibly undergo secondary impacts on the slider surface following air flow, which further lower the particles' velocity and increases the possibility of particles adhere to the slider surface. [ABSTRACT FROM AUTHOR]

This article presents a reverse modeling of the headform when wearing a filtering facepiece respirator (FFR) and a computational fluid dynamics (CFD) simulation based on the modeling. The whole model containing the upper respiratory airway, headform, and FFR was directly recorded by computed tomography (CT) scanning, and a medical contrast medium was used to make the FFR “visible.” The FFR was normally worn by the subject during CT scanning so that the actual deformation of both the FFR and the face muscles during contact can be objectively conserved. The reverse modeling approach was introduced to rebuild the geometric model and convert it into a CFD solvable model. In this model, we conducted a transient numerical simulation of air flow containing carbon dioxide, thermal dynamics, and pressure and wall shear stress distribution in the respiratory system taking into consideration an individual wearing a FFR. The breathing cycle was described as a time-dependent profile of the air velocity through the respiratory airway. The result shows that wearing the N95 FFR results in CO2accumulation, an increase in temperature and pressure elevation inside the FFR cavity. The volume fraction of CO2reaches 1.2% after 7 breathing cycles and then is maintained at 3.04% on average. The wearers re-inhale excessive CO2in every breathing cycle from the FFR cavity. The air temperature in the FFR cavity increases rapidly at first and then stays close to the exhaled temperature. Compared to not wearing an FFR, wearers have to increase approximately 90 Pa more pressure to keep the same breathing flow rate of 30.54 L/min after wearing an FFR. The nasal vestibule bears more wall shear stress than any other area in the airway. [ABSTRACT FROM AUTHOR]

The reliability and stability of hard disk drives (HDDs) are especially important as the areal recording density is rapidly increasing and target to 10 Tb/in2 in the future. The vibrations of the head gimbals assembly (HGA) are inevitable by internal fluid flow and external shock impulses. In this paper, a 3-D finite-element model of an HDD is developed. The internal flow-induced HGA vibrations are investigated by a fluid–structure interaction approach. The external shock-induced vibrations of HGA are also analyzed. The investigated filling gases in the HDD include air and helium. [ABSTRACT FROM AUTHOR]

Nowadays, hard disk drive filling with helium has emerged to achieve highly stable magnetic recording. The bearing force in helium is different from that in air. This paper uses the 3-D direct simulation Monte Carlo method to investigate the bearing force over bit-patterned media in the filling gases of air and helium under different conditions, including groove depth, ambient temperature, slider surface temperature, rotation speed of the disk, and different velocity losses during the collision process between the gas molecules and the slider. [ABSTRACT FROM AUTHOR]

This paper presents a numerical method to simulate the particle trajectory in the head–disk interface (HDI). The simulator solves the reduced Navier–Stokes equation with the second-slip boundary conditions to get the air velocity distribution, then solves the motion equations of particles and obtains the trajectories of the particles in the HDI using the binary Lagrange interpolation and the fourth-order Runge–Kutta method. The calculated trajectories of particles follow well with the air streamlines in the recessed regions. The particle density, diameter, and initial entering velocity have different effects on particle movement. Furthermore, particle velocity behaviors in the recessed regions are investigated for the first time. The particle is accelerated or decelerated by the action of the drag force and becomes close to the velocity of local air flow. Such effects are more obvious for small particles than large particles. The particle velocity becomes very small when it is close to the leading edge of the trailing pad. The numerical results also show that the particle goes up when it crosses the transition regions, and the particle moves upward more sharply with higher initial entrance height due to the larger vertical velocity of the local air flow. [ABSTRACT FROM AUTHOR]

Diamond (110) surface is one of the low-index diamond faces but its effects on nitrogen-vacancy (NV) based quantum sensor remain unclear. The fluorine, hydrogen, nitrogen, and oxygen-terminated diamond (110) surfaces used for the NV centers are proposed here, and their electronic properties are investigated based on first-principles calculations. The oxygen-terminated diamond (110) surface has inter-bandgap states and surface electron spins, the nitrogen-terminated (110) surface has inter-band gap states, and the hydrogen-terminated (110) surface has negative electron affinity. Thus, these three surfaces may not be suitable for shallow NV centers. The fluorine-terminated diamond (110) surface has positive electron affinity, no surface related inter bandgap states, and no surface electron spins, so it is a promising candidate for NV-based quantum sensors. [Display omitted] [ABSTRACT FROM AUTHOR]