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      • KCI등재

        留学生语伴互助对外语学习自我效能感的影响研究

        류군 ( Liu¸ Jun ) 한국중국언어학회 2021 중국언어연구 Vol.- No.96

        Based on the S-O-R theoretical model, this study analyzed the effect of language partnership on self-efficacy by selecting international students’ subjects. The following conclusions were drawn from descriptive statistics, relevant analyses, structural equation model verification and brokerage effect analysis of the research data: First, the cooperation in acquiring foreign language knowledge in the cooperation process of international students’ language partners has a great effect on helping them to increase their sense of learning effectiveness when learning a foreign language. Second, the cooperation of foreign language applications in the cooperation process of international language partners helps international students use the foreign language knowledge they have learned in real-life relationships, and greatly affects the effectiveness of learning foreign language learning. Third, foreign language emotional cooperation in the cooperation process of foreign language partners is relatively special, and research shows that it helps students learn foreign languages and experience emotions in studying abroad, and increases in their foreign language learning efficacy. Fourth, in the course of cooperation with foreign language partners, students learn foreign language easily through cooperation, and experience experience, language application practice, and emotion, and this synesthesia emotional experience affects the effectiveness of foreign language learning. The results of the research data show that the mutual assistance between the language partners of foreign students produces a sense of identification such as ease of foreign language learning, practical foreign language application and emotional experience. The model constructed in the final research process is verified: the mutual assistance between foreign students’ foreign language partners Self-efficacy in foreign language learning has a positive effect.

      • Direct-current triboelectricity generation by a sliding Schottky nanocontact on MoS<sub>2</sub> multilayers

        Liu, Jun,Goswami, Ankur,Jiang, Keren,Khan, Faheem,Kim, Seokbeom,McGee, Ryan,Li, Zhi,Hu, Zhiyu,Lee, Jungchul,Thundat, Thomas Nature Publishing Group UK 2018 Nature nanotechnology Vol.13 No.2

        <P>The direct conversion of mechanical energy into electricity by nanomaterial-based devices offers potential for green energy harvesting(1-3). A conventional triboelectric nanogenerator converts frictional energy into electricity by producing alternating current (a.c.) triboelectricity. However, this approach is limited by low current density and the need for rectification(2). Here, we show that continuous direct-current (d.c.) with a maximum density of 10(6) A m(-2) can be directly generated by a sliding Schottky nanocontact without the application of an external voltage. We demonstrate this by sliding a conductive-atomic force microscope tip on a thin film of molybdenum disulfide (MoS2). Finite element simulation reveals that the anomalously high current density can be attributed to the non-equilibrium carrier transport phenomenon enhanced by the strong local electrical field (105-106 V m(-2)) at the conductive nanoscale tip(4). We hypothesize that the charge transport may be induced by electronic excitation under friction, and the nanoscale current-voltage spectra analysis indicates that the rectifying Schottky barrier at the tip-sample interface plays a critical role in efficient d.c. energy harvesting. This concept is scalable when combined with microfabricated or contact surface modified electrodes, which makes it promising for efficient d.c. triboelectricity generation.</P>

      • KCI등재

        Preparation of Flame Retardant and Antibacterial Wood with Composite Membrane Coating

        ( Jun-xian Xu ),( Yang Liu ),( Ming-yu Wen ),( Hee-jun Park ),( Jia-zhi Zhu ),( Yu-nan Liu ) 한국목재공학회 2021 목재공학 Vol.49 No.6

        A novel flame retardant and antibacterial composite membrane coating for wood surfaces was prepared by adding POSS-based phosphorous nitrogen flame retardant (later referred to as NH<sub>2</sub>-POSS) and silver nanoparticles (Ag NPs) to chitosan (CS). The effects of NH<sub>2</sub>-POSS content (mass fractions of CS 0%, 0.5%, 1%, 3%, 5%, and 7%) on the structure and properties of the composite membrane coating on wood were investigated. The composite film was prepared by the method of blending and ducting. Contact angle, tensile property and antibacterial effects of the composite film were measured, and infrared spectroscopy was used. The results show that the addition of NH<sub>2</sub>-POSS can not only improve the toughness of the membrane, but also the flame retardancy of the membrane, which improves the application of the membrane in wood products. However, with the addition of NH<sub>2</sub>-POSS, the transparency of the composite membrane was weakened. The inhibitory effect of the composite membrane on the growth of Escherichia coli was enhanced with the increase in Ag NPs. This research provides a foundation for the application of functional wood.

      • KCI등재

        Structural and Functional Neural Alterations in Internet Addiction: A Study Protocol for Systematic Review and Meta-Analysis

        Jun-Li Liu,Jing-Ting Sun,Hui-Lin Hu,Hao-Yuan Wang,Yun-Xi Kang,Tian-Qi Chen,Zhu-Hong Chen,Yu-Xuan Shang,Yu-Ting Li,Bo Hu,Rui Liu 대한신경정신의학회 2023 PSYCHIATRY INVESTIGATION Vol.20 No.1

        A growing number of neuroimaging studies have revealed abnormal brain structural and functional alterations in subjects with internet addiction (IA), however, with conflicting conclusions. We plan to conduct a systematic review and meta-analysis on the studies of voxelbased morphometry (VBM) and resting-state functional connectivity (rsFC), to reach a consolidated conclusion and point out the future direction in this field. A comprehensive search of rsFC and VBM studies of IA will be conducted in the PubMed, Cochrane Library, and Web of Science databases to retrieve studies published from the inception dates to August 2021. If the extracted data are feasible, activation likelihood estimation and seed-based d mapping methods will be used to meta-analyze the brain structural and functional changes in IA patients. This study will hopefully reach a consolidated conclusion on the impact of IA on human brain or point out the future direction in this field.

      • SCIESCOPUSKCI등재
      • Sustained electron tunneling at unbiased metal-insulator-semiconductor triboelectric contacts

        Liu, Jun,Miao, Mengmeng,Jiang, Keren,Khan, Faheem,Goswami, Ankur,McGee, Ryan,Li, Zhi,Nguyen, Lan,Hu, Zhiyu,Lee, Jungchul,Cadien, Ken,Thundat, Thomas Elsevier 2018 Nano energy Vol.48 No.-

        <P><B>Abstract</B></P> <P>Generating sufficient current density for powering electronic devices remains as one of the critical challenges of mechanical energy harvesting techniques based on piezo and triboelectricity, mainly due to the high impedance of the insulating material systems. Here we report on producing sustainable tunneling current using an unbiased, triboelectrically charged metal-insulator-semiconductor (MIS) point contact system, consisting of p-type silicon, silicon oxide and a metal tip. The native thin oxide (~ 1.6 nm) on the silicon surface provides a natural pathway for quantum mechanical tunneling of the triboelectrically generated electrons into the silicon substrate. Lateral back and forth sliding motion of the tip, irrespective of the direction of motion, generates a constant direct current (d.c.) with very high current density. The measured current shows an exponential decay with the thickness of oxide layer deposited with atomic layer deposition (ALD), confirming the quantum mechanical tunneling mechanism. It is proposed that the contact potential difference enhanced by triboelectric charging provides potential difference between metal point contact and the substrate. With single metallic micro probe sliding on a moderately doped p-type silicon, an open circuit voltage (<I>V</I> <SUB>oc</SUB>) of 300–400 mV and a short-circuit direct current (<I>I</I> <SUB>sc</SUB>) of 3–5 μA (a corresponding high current density, <I>J</I>, in the order of 1–10 A/m<SUP>2</SUP>) have been observed. It is predicted from conductive-atomic force microscopy (C-AFM) experiment that the theoretical <I>J</I> can be as high as 10<SUP>4</SUP> A/m<SUP>2</SUP>. This new concept has the potential as a green energy harvesting technique where a broad range of material candidates and device configurations could be used.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Quantum mechanical tunneling at triboelectrically charged interface through ultrathin oxide layer is demonstrated. </LI> <LI> Tribo-tunneling is found to be a universal phenomenon in MIS frictional contact system. </LI> <LI> High current density <I>J</I> of 5 A/m<SUP>2</SUP> is experimentally measured in doped silicon materials at macroscale. </LI> <LI> Ultrahigh C-AFM <I>J</I> of 10<SUP>4</SUP> A/m<SUP>2</SUP> is observed due to the nano-size probe-induced high electric field. </LI> <LI> This method can be used as cost-effective triboelectric DC current generator, due to easily available silicon wafers with native oxide. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

      • Analysis of Key Genes and Pathways Associated with Colorectal Cancer with Microarray Technology

        Liu, Yan-Jun,Zhang, Shu,Hou, Kang,Li, Yun-Tao,Liu, Zhan,Ren, Hai-Liang,Luo, Dan,Li, Shi-Hong Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.3

        Objective: Microarray data were analyzed to explore key genes and their functions in progression of colorectal cancer (CRC). Methods: Two microarray data sets were downloaded from Gene Expression Omnibus (GEO) database and differentially expressed genes (DEGs) were identified using corresponding packages of R. Functional enrichment analysis was performed with DAVID tools to uncover their biological functions. Results: 631 and 590 DEGs were obtained from the two data sets, respectively. A total of 32 common DEGs were then screened out with the rank product method. The significantly enriched GO terms included inflammatory response, response to wounding and response to drugs. Two interleukin-related domains were revealed in the domain analysis. KEGG pathway enrichment analysis showed that the PPAR signaling pathway and the renin-angiotensin system were enriched in the DEGs. Conclusions: Our study to systemically characterize gene expression changes in CRC with microarray technology revealed changes in a range of key genes, pathways and function modules. Their utility in diagnosis and treatment now require exploration.

      • Exogenous p53 Upregulated Modulator of Apoptosis (PUMA) Decreases Growth of Lung Cancer A549 Cells

        Liu, Chun-Ju,Zhang, Xia-Li,Luo, Da-Ya,Zhu, Wei-Feng,Wan, Hui-Fang,Yang, Jun-Ping,Yang, Xiao-Jun,Wan, Fu-Sheng Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.2

        Purpose: To investigate the influence of exogenous p53 upregulated modulator of apoptosis (PUMA) expression on cell proliferation and apoptosis in human non-small cell lung cancer A549 cells and transplanted tumor cell growth in nude mice. Materials and Methods: A549 cells were divided into the following groups: control, non-carrier (NC), PUMA (transfected with pCEP4-(HA) 2-PUMA plasmid), DDP ($10{\mu}g/mL$ cisplatin treatment) and PUMA+DDP (transfected with pCEP4-(HA)2-PUMA plasmid and $10{\mu}g/mL$ cisplatin treatment). The MTT method was used to detect the cell survival rate. Cell apoptosis rates were measured by flow cytometry, and PUMA, Bax and Bcl-2 protein expression levels were measured by Western blotting. Results: Compared to the control group, the PUMA, DDP and PUMA+DDP groups all had significantly decreased A549 cell proliferation (p<0.01), with the largest reduction in the PUMA+DDP group. Conversely, the apoptosis rates of the three groups were significantly increased (P<0.01), and the PUMA and DDP treatments were synergistic. Moreover, Bax protein levels significantly increased (p<0.01), while Bcl-2 protein levels significantly decreased (p<0.01). Finally, both the volume and the weights of transplanted tumors were significantly reduced (p<0.01), and the inhibition ratio of the PUMA+DDP group was significantly higher than in the single DDP or PUMA groups. Conclusions: Exogenous PUMA effectively inhibited lung cancer A549 cell proliferation and transplanted tumor growth by increasing Bax protein levels and reducing Bcl-2 protein levels.

      • Piezoelectric 6-dimensional accelerometer cross coupling compensation algorithm based on two-stage calibration

        Jun Liu,Dengzhuo Zhang,Min Liu,Tongbao Zhu,Lan Qin,Jingcheng Liu 국제구조공학회 2023 Smart Structures and Systems, An International Jou Vol.32 No.2

        In order to improve the measurement accuracy of the 6-dimensional accelerometer, the cross coupling compensation method of the accelerometer needs to be studied. In this paper, the non-linear error caused by cross coupling of piezoelectric sixdimensional accelerometer is compensated online. The cross coupling filter is obtained by analyzing the cross coupling principle of a piezoelectric six-dimensional accelerometer. Linear and non-linear fitting methods are designed. A two-level calibration hybrid compensation algorithm is proposed. An experimental prototype of a piezoelectric six-dimensional accelerometer is fabricated. Calibration and test experiments of accelerometer were carried out. The measured results show that the average nonlinearity of the proposed algorithm is 2.2628% lower than that of the least square method, the solution time is 0.019382 seconds, and the proposed algorithm can realize the real-time measurement in six dimensions while improving the measurement accuracy. The proposed algorithm combines real-time and high precision. The research results provide theoretical and technical support for the calibration method and online compensation technology of the 6-dimensional accelerometer.

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