Investigation of Different Conduction States on the Performance of NMOS-Based Power Clamp ESD Device

Wei Weipeng,Wang Yang,Chen Xijun,Zheng Yifei,Li Jieyu,Cao Pei,Cao Wenmiao 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.3

This article investigates the eff ects of diff erent gate coupling voltage and gate voltage duration on electro-static discharge (ESD) performance of several NMOS-based power rail protection devices. Through simulation and transmission line pulse (TLP) test, it is found that there are two modes in the conduction process of the main clamping NMOS: channel conduction state and parasitic NPN conduction state. Diff erent gate voltage and duration bring the two conduction states diff erent proportions in the whole working process, which give the device very diff erent robustness. The results show that under the condition of small gate voltage and long duration and the condition of large gate voltage and short duration, the device can achieve optimal performance because the trigger voltage can be reduced, and the parasitic NPN can be turned on in time to release most of the current

Hierarchical Reinforcement Learning Based on KNN Classification Algorithms

Shanhong Zhu,Weipeng Dong,Wei Liu 보안공학연구지원센터 2015 International Journal of Hybrid Information Techno Vol.8 No.8

In recent years, machine learning is increasingly becoming an important field of computer science. A new method using KNN classification algorithm identifies the layered boundary to find subgoal condition, to automatic classifying of large state space, reaches the dimension reduction of state space, and on the basis of generated subspace classifying to structure subtasks, and then realizes the hierarchical learning tasks automatically. In autonomous system, Agent assigns to their task through interaction with the environment, using hierarchical reinforcement learning technology can help the Agent in the large, complex environment to improve learning efficiency. Through the experimental results the effectiveness of the proposed algorithm is demonstrated. The goal of this paper is to provide a basic overview for both specialists and non-specialists to how to decide a good reinforcement learning algorithm for classification.

Tribological performances of copper perrhenate/graphene nanocomposite as lubricating additive under various temperatures

Junhai Wang,Weipeng Zhuang,Tingting Yan,Wenfeng Liang,Ting Li,Lixiu Zhang,Xiaoyi Wei 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.100 No.-

Herein, copper perrhenate (Cu(ReO4)2) was synthesized using a micro-emulsion method and adhered tographene (Gr) using an ultrasonic process. Then, the as-prepared Cu(ReO4)2/Gr composite was added intothe synthetic oil as a lubricant additive with the help of ionic liquid to achieve enhanced dispersionstability within the base oil. The tribological performances of the Cu(ReO4)2/Gr additive wereinvestigated using four-ball tests and the ball-on-disk reciprocating configuration under varioustemperatures. The potential lubrication mechanisms of the Cu(ReO4)2/Gr additive were performed usinga series of characterization methods including XRD, Raman, SEM-EDS, TEM, DSC/TG, and XPS. The resultsof four-ball tests at room temperature indicated that the Cu(ReO4)2/Gr additive could substantiallyimprove the tribological performances of the base oil. The smallest coefficient of friction (COF) and wearscar diameter (WSD) values were 0.068 and 495 mm, respectively, when 0.05 wt% of Cu(ReO4)2/Gr wasadded. Additionally, the graphene accelerated friction-induced heat transfer, which led to decreasedfriction and wear. The results of reciprocating friction experiments at elevated temperatures revealedthat the Cu(ReO4)2/Gr additive had excellent friction-reduction properties when the temperature washigh. This could be attributed to the generation of a protective layer containing tribo-oxides from thealloy, some residual carbides and copper perrhenate induced by friction heat and stress. This protectivelayer was uniformly and stably covered on the worn surface, which could effectively alleviate directcontact between the rubbing pair.

Synthesis of Co:MgAl2O4 nano-powders for saturable absorber

Wang Chuanyun,Yang Wei,Wang Zhiqi,Liu Bina,Li Shihua,Lu Taoa,,Li Xueren,Miao Weipeng,Luo Wei 한양대학교 청정에너지연구소 2023 Journal of Ceramic Processing Research Vol.24 No.2

Uniform Co:MgAl2O4 nano-powders for saturable absorber were prepared using inverse-drip co-precipitation method. Effectsof the precipitant and the metal ion solution on the composition and morphology of Co:MgAl2O4 nano-powders were studied. The results show that pure Co:MgAl2O4 nano-powders can be obtained, using the mixed solution of ammonium carbonate andammonia as the precipitant. The specific surface area of the particles reached 36 m2/g and the primary particle size was 39nm according to the SEM images and BET results.

Concomitance of P-gp/LRP Expression with EGFR Mutations in Exons 19 and 21 in Non-Small Cell Lung Cancers

Shen Lu,Hong Wei,Weipeng Lu,Mei Li,Qiuping Zhang 연세대학교의과대학 2016 Yonsei medical journal Vol.57 No.1

Purpose: Traditional chemotherapy is the main adjuvant therapy for the treatment of non-small cell lung cancer (NSCLC). However,the emergence of multi-drug resistance (MDR) has greatly restricted the curative effect of chemotherapy. Therefore, it isnecessary to find a method to treat MDR NSCLC clinically. It is worth investigating whether NSCLCs that are resistant to traditionalchemotherapy can be effectively treated with tyrosine kinase inhibitors targeting epidermal growth factor receptor (EGFR). Materials and Methods: The expression of P-glycoprotein (P-gp) and lung resistance-related protein (LRP) was detected by immunohistochemistry,and mutations in EGFR (exons 19 and 21) and Kirsten rat sarcoma viral oncogene homolog (KRAS) (exon 2)were detected by high-resolution melting analysis (HRMA) of surgical NSCLC specimens from 127 patients who did not undergotraditional chemotherapy or radiotherapy. A Pearson chi-square test was performed to analyze the correlations between the expressionof P-gp and LRP and mutations in EGFR and KRAS. Results: The expression frequencies of P-gp and LRP were significantly higher in adenocarcinomas from non-smoking patients;the expression frequency of LRP was significantly higher in cancer tissue from female patients. The frequency of EGFR mutationswas significantly higher in well to moderately differentiated adenocarcinomas from non-smoking female patients. The frequencyof EGFR mutations in the cancers that expressed P-gp, LRP, or both P-gp and LRP was significantly higher than that in cancersthat did not express P-gp or LRP. Conclusion: NSCLCs expressing P-gp/LRP bear the EGFR mutation in exon 19 or 21 easily.

Adsorption Mechanism of Magnetic Induction Free- Abrasive Grain and Its Effect on Cutting Performance of Wire Saws

Wei Peng,Teng-wei Qiu,Chun-yan Yao,Chen Tang,Wei Zhang 한국정밀공학회 2015 International Journal of Precision Engineering and Vol. No.

This paper proposes a method of free-abrasive wire sawing in the magnetic field. Magnetic abrasive grains are absorbed on surface of the wire by magnetic force, and therefore more magnetic abrasive grains are carried into cutting area. This mechanism is helpful to improve the cutting performance of wire saws. Theoretical modeling of the movement trajectory of magnetic abrasive grains is done in the magnetic field, and it is also verified by observation experiments of movement trajectory of magnetic abrasive grains. Absorption angle, which is used as the indicator of adsorption capacity about magnetic abrasive grain on surface of the wire, is proposed in this paper. The effect of magnetic field intensity on absorption angle is analyzed through computer simulations and observation experiments. Practical experiments and cutting results show that the change of magnetic field intensity has a significant impact on cutting efficiency, surface roughness, and kerf width.

A multipath peroxymonosulfate activation process over supported by magnetic CuO-Fe3O4 nanoparticles for efficient degradation of 4-chlorophenol

Wei Peng,Jie Liu,Wei Peng,Chenxu Li,Fuxing Zong,Wensi Xu,Xing Zhang 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.8

Heterogeneous catalysts with low cost, environmentally friendly, highly effective and ready separation from aqueous solution are highly desirable. Magnetic CuO-Fe3O4 nanoparticles, a type of non-toxic bimetallic transition metal oxide, is a promising heterogeneous catalyst for activation of peroxymonosulfate (PMS) to generate reactive oxygen species (ROS) that has not been previously investigated. In this study, the activation of PMS by CuO-Fe3O4 nanoparticles was evaluated using the degradation of 4-chlorophenol as a model reaction. Several critical factors such as pH, catalyst dosage and PMS concentration were investigated. CuO-Fe3O4/PMS system demonstrated a wide effective pH range to degrade 4-chlorophenol, namely 5.5 to 9.5. With the increase of the catalyst dosage, the degradation efficiency of 4-chlorophenol appeared to increase first and then decrease, that the inflection point was 0.5 g/L. Elevated PMS concentration obviously improved the decomposition of 4-chlorophenol; however, the plateau was reached when the PMS concentration was 8mM. Further increase in PMS concentration would not significantly improve the removal efficiency. Through examining the effects of scavengers and electron spin resonance (ESR) analyses, CuO-Fe3O4 nanoparticles were proven to activate PMS through a non-radical and radical pathway to generate singlet oxygen, sulfate radicals and hydroxyl radicals. Based on results, CuO-Fe3O4 nanoparticles were effective, environmentally friendly and low cost catalysts for efficient activation of PMS. These features make CuO-Fe3O4 nanoparticles a readily available heterogeneous catalyst to activate PMS for refractory organic pollutants degradation in advanced oxidation processes (AOPs).

Calculation of Suspending Force for Double Stator Type 12/8 Pole BLSRM

Wei Peng,Dong-Hee Lee(이동희),Jin-Woo Ahn(안진우) 대한전기학회 2011 대한전기학회 학술대회 논문집 Vol.2011 No.10-2

Attention and Working Memory Task- Load Dependent Activation Increase with Deactivation Decrease after Caffeine Ingestion

Wei Peng,Jian Zhang,Da Chang,Zhuo-Wen Shen,Yuanqi Shang,Donghui Song,Qiu Ge,Xuchu Weng,Ze Wang 대한자기공명의과학회 2017 Investigative Magnetic Resonance Imaging Vol.21 No.4

Purpose: Caffeine is the most widely consumed psychostimulant. It is often adopted as a tool to modulate brain activations in fMRI studies. However, its pharmaceutical effect on task-induced deactivation has not been fully examined in fMRI. Therefore, the purpose of this study was to examine the effect of caffeine on both activation and deactivation under sustained attention. Materials and Methods: Task fMRI was acquired from 26 caffeine naive healthy volunteers before and after taking caffeine pill (200 mg). Results: Statistical analysis showed an increase in cognition-load dependent task activation but a decrease in load dependent de-activation after caffeine ingestion. Increase of attention and memory task activation and its load-dependence suggest a beneficial effect of caffeine on the brain even though it has no overt behavior improvement. The reduction of deactivation by caffeine and its load-dependence indicate reduced facilitation from task-negative networks. Conclusion: Caffeine affects brain activity in a load-dependent manner accompanied by a disassociation between task-positive network and task-negative network.

Control of Radial Force in Double Stator Type Bearingless Switched Reluctance Motor

Wei Peng,Zhenyao Xu,Dong-Hee Lee,Jin-Woo Ahn 대한전기학회 2013 Journal of Electrical Engineering & Technology Vol.8 No.4

Modeling and control of radial force in the double stator type bearingless switched reluctance motor (BLSRM) is researched. The rotational torque is controlled independently from the radial force control. And the radial force is constant which is independent from the rotor position. In order to realize steady suspension, analytical models of torque and radial force for the proposed structure are derived. Meanwhile, in order to realize steady suspension, control scheme for proposed BLSRM is proposed. In the control method, the radial force can be controlled in arbitrary direction and magnitude by selecting some combinations of radial force windings. The validities of structure and control method are verified by the experimental results.