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Tong Liu,Rong Huang,Fangsen Li,Zengli Huang,Jian Zhang,Jianping Liu,Liqun Zhang,Shuming Zhang,An Dingsun,Hui Yang 한국물리학회 2018 Current Applied Physics Vol.18 No.7
The accuracy and error propagation for determining the low specific contact resistance of Ohmic contacts on IIIV wide band-gap semiconductors based on the circular transmission line model have been analyzed and the validity of this method is discussed in detail. The accuracy is more susceptible to the factors including data fitting method, electrical measurement technique and contact area correction. By using the equations of the original circular transmission line model to extract the fitting parameters, the calculation accuracy is much improved and the inapplicability of the linear least-square fitting is prevented. To further improve the accuracy, a four-probe current-voltage measurement technique was adopted to reduce the parasitic series resistances and the uncertainty bound, especially for the Ohmic contact with low sheet resistance of the semiconductor. Moreover, we have studied the size effect of contact pads of patterns and demonstrated that contact area correction is necessary for the semiconductor with high sheet resistance. A comprehensive error analysis is also performed to fully understand all the impact factors on this advanced method of specific contact resistance measurement, which is benefit for device performance evaluation and failure analysis.
Lingang Zhang,Shuo Zhou,Yi Xuan,Miao Sun,Liqun Zhao 한국식물학회 2009 Journal of Plant Biology Vol.52 No.2
Nitric oxide (NO) is a key molecule involved in many physiological processes. To characterize its roles in the tolerance of Arabidopsis thaliana to ultraviolet-B (UV-B), we investigated the effect of a reduced endogenous NO level on oxidative damage to wild-type and mutant (Atnoa1) plants. Under irradiation, hydrogen peroxide was accumulated more in mutant leaves than in the wild type. However, the amounts of UV-B-absorbing compounds (flavonoids and anthocyanin) and the activities of two antioxidant enzymes—catalase (CAT, EC 1.11.1.6) and ascorbate peroxidase (APX, EC 1.11.1.11)—were lower in leaves of the former. Supplementing with sodium nitroprusside, an NO donor, could alleviate the oxidative damage to mutant leaves by increasing flavonoid and anthocyanin contents and enzyme activities. In comparison, Nw ? nitro ? l ? arginine, an inhibitor of nitric oxide synthase, had the opposite effects on oxidation resistance in wild-type leaves. All these results suggest that nitric oxide acts as a signal for an active oxygen-scavenging system that protects plants from oxidative stress induced by UV-B irradiation.
Duan Liqun,Huang Jinlong,Zhang Yong,Pi Guoliang,Ying Xiaofang,Zeng Fanyu,Hu Desheng,Ma Jia 한국유전학회 2023 Genes & Genomics Vol.45 No.6
Background Nasopharyngeal carcinoma (NPC) is the most common head and neck tumor in China. Forkhead box (FOX) proteins have 19 subfamilies, which can maintain cell metabolism, regulate cell cycle and cell growth, etc. FOXK1 is a member of the FOX family, and studies have found that FOXK1 is closely related to tumors. Objective This experiment aims to study the effects of FOXK1 interference on proliferation, apoptosis, invasion, epithelial-mesenchymal transition (EMT), and radiosensitivity, by regulating the Janus kinas/signal translator and activator of the transfer 3 (JAK/STAT3) pathway. Methods The expression of FOXK1 was detected via immunohistochemistry using clinical nasopharyngeal carcinoma tissues and adjacent tissues. The relationship between FOXK1 expression and tumor stage was subsequently evaluated. The colony formation rate was calculated through the colony formation experiment. Cell apoptosis and cell cycle distribution were detected using flow cytometry, while cell invasion was detected using the Transwell method. The number of cells in the nucleus of each group after 30 min, 4 h, and 24 h of radiotherapy with the 2 Gy dose was counted using immunofluorescence under γ-H2AX focal points of a laser confocal microscope. Results FOXK1 is clearly expressed in the patients’ cancer tissues. The expression of FOXK1 was significantly correlated with the patient’s sex. FOXK1 interference or Peficitinib can upregulate the apoptosis rate of 5-8 F and CNE-2 cells; increase the G2 phase of cells; and inhibit the invasion, migration, and EMT of cells. At the same time, FOXK1 interference can downregulate the protein expression of p-JAK1, p-JAK2, and p-STAT3 in cells. Interference from FOXK1 or Peficitinib alone can reduce the rate of cell colony formation under different radiation doses, and enhance the green fluorescence intensity of γ-H2AX in the nucleus after 4 and 24 h of the 2 Gy dose of radiotherapy. These results are optimal when FOXK1 interference and Peficitinib are used together. Conclusion FOXK1 interference in NPC cells can regulate EMT through the JAK/STAT3 signal pathway, enhance the radiosensitivity of cells, and thus inhibit tumor cell progression.
Zhenpeng Tao,Liqun Wu,Yangquan Jiao,Hui Rong,Fan Zhang,Xuesong Lu 한국지질과학협의회 2022 Geosciences Journal Vol.26 No.5
The spatial distribution of flow units and reductant within a sandstone uranium reservoir is very beneficial for exploring the uranium mineralization mechanism; however, such studies have been almost neglected. As such, this paper aims to provide the sedimentological interpretation and heterogeneity models of the sandstone of the Middle Jurassic Zhiluo Formation at Shiwan outcrop area, in the eastern Ordos Basin. The outcrops are sandstone-dominated subaqueous distributary channel successions, in which five distinct architectural elements are identified and interpreted: channel units (CU), downstream accretion elements (DA), lateral accretion elements (LA), sandy bedforms (SB) and no-channelized fine-grained sediments (NFS). Within the sandstone succession, six flow units are present in the middle and lower parts of CU, or the lower parts of DA and SB elements, with their geometry to be controlled by the fourth- or third-order bounding surfaces. Moreover, the carbonaceous debris-rich zones (CDZ) are places with the highest abundance of reductant and preserve exclusively upon the basal erosional surfaces of CU and DA elements. Based on those results, a prediction model is established and shows that the formation of interlayer oxidation zone is strongly selective and confined within the CU and DA elements. The favorable site of uranium mineralization is preferentially distributed in the transition zone between the front of flow unit and the CDZ.
Manfa Yuan,Jin Zhang,Yunlai Deng,Xiaobin Guo,Liqun Guan 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.5
Noteworthy ductility Mg-8Gd-4Y-1Nd-0.5Si (wt.%) alloy with a strong non-basal texture was developed by 12 passes ofmulti-directional forging (MDF) combine with extrusion. The slip trace analysis indicated that deformation mechanism after3 passes of MDF and extrusion were basal < a > , pyramidal < a > and pyramidal < c + a > slips. The intensity of non-basaltexture increased from 5.37 to 8.03 with the MDF passes increased from 3 to 12, which means grain orientation tends tobe more consistent and makes the basal < a > slips easy to pass through grain boundaries to accommodate ductility. Withmore basal < a > slips crossing the grain boundaries, dislocation interaction in grain interior caused stress accumulation,exceeding the critical shear stress (CRSS) of slips with low schmidt factor (SF), and multiple slips appeared. The activationof slip cross grain boundary and multiple slip improved the elongation from 14.7% to 25.6% of MDFs-extruded Mg-8Gd-4Y-1Nd-0.5Si alloy.
Rapid Detection of Clostridium tetani by Recombinase Polymerase Amplification Using an Exo Probe
( Mingjing Guo ),( Pan Feng ),( Liqun Zhang ),( Chunfeng Feng ),( Jie Fu ),( Xiaoyun Pu ),( Fei Liu ) 한국미생물 · 생명공학회 2022 Journal of microbiology and biotechnology Vol.32 No.1
Tetanus is a potentially fatal public health illness resulted from the neurotoxins generated by Clostridium tetani. C. tetani is not easily culturable and culturing the relevant bacteria from infected wounds has rarely been useful in diagnosis; PCR-based assays can only be conducted at highly sophisticated laboratories. Therefore, a real-time recombinase polymerase amplification assay (Exo-RPA) was constructed to identify the fragments of the neurotoxin gene of C. tetani. Primers and the exo probe targeting the conserved region were designed, and the resulting amplicons could be detected in less than 20 min, with a detection limit of 20 copies/reaction. The RPA assay displayed good selectivity, and there were no cross-reactions with other infectious bacteria common in penetrating wounds. Tests of target-spiked serum and pus extract revealed that RPA is robust to interfering factors and has great potential for further development for biological sample analysis. This method has been confirmed to be reliable for discriminating between toxic and nontoxic C. tetani strains. The RPA assay dramatically improves the diagnostic efficacy with simplified device architecture and is a promising alternative to real-time PCR for tetanus detection.
Electromagnetic Counter-recoil Mechanism Based on Adaptive Sliding Mode Control
Wenbin Yu,Guolai Yang,Liqun Wang,Lei Li,Hongyi Zhang 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.9
Traditional counter-recoil machines always have problems of difficulty in adjusting the movement process flexibly, maintenance difficulties, and so on. To end these, this paper proposes a new electromagnetic counterrecoil scheme using cylindrical linear motors. Firstly, the mathematical expression of counter-recoil movement under the linear motor is formulated, and the ideal movement trajectory is designed using the piecewise polynomial of velocity based on acceleration. To obtain a better performance, of the motor controller, a composed approach of an adaptive sliding mode control based on barrier function (BFASMC) and the finite-time disturbance observer (FTDO) is introduced into the modeling and computation. The stability of the controller is proved by establishing the Lyapunov function. The new adaptive laws based on the barrier function effectively make up for the shortcomings of the exponential function and improves control chattering. At last, the new scheme is simulated. The results show that it has a strong robustness and anti-interference ability.