Surface oxidation and thermoelectric properties of indium-doped tin telluride nanowires

Li, Zhen,Xu, Enzhi,Losovyj, Yaroslav,Li, Nan,Chen, Aiping,Swartzentruber, Brian,Sinitsyn, Nikolai,Yoo, Jinkyoung,Jia, Quanxi,Zhang, Shixiong The Royal Society of Chemistry 2017 Nanoscale Vol.9 No.35

<P>The recent discovery of excellent thermoelectric properties and topological surface states in SnTe-based compounds has attracted extensive attention in various research areas. Indium doped SnTe is of particular interest because, depending on the doping level, it can either generate resonant states in the bulk valence band leading to enhanced thermoelectric properties, or induce superconductivity that coexists with topological states. Here we report on the vapor deposition of In-doped SnTe nanowires and the study of their surface oxidation and thermoelectric properties. The nanowire growth is assisted by Au catalysts, and their morphologies vary as a function of substrate position and temperature. Transmission electron microscopy characterization reveals the formation of an amorphous surface in single crystalline nanowires. X-ray photoelectron spectroscopy studies suggest that the nanowire surface is composed of In2O3, SnO2, Te and TeO2which can be readily removed by argon ion sputtering. Exposure of the cleaned nanowires to atmosphere leads to rapid oxidation of the surface within only one minute. Characterization of electrical conductivity<I>σ</I>, thermopower<I>S</I>, and thermal conductivity<I>κ</I>was performed on the same In-doped nanowire which shows suppressed<I>σ</I>and<I>κ</I>but enhanced<I>S</I>yielding an improved thermoelectric figure of merit<I>ZT</I>compared to the undoped SnTe.</P>

Analysis on Influence Domain of Control Flow Modification in Regression Testing based on FCP

Mingjue Hu,Yongmin Mu,Aiping Xu 보안공학연구지원센터 2016 International Journal of Security and Its Applicat Vol.10 No.6

After the version changes,locatingthe influence domain of control flow modificationis a hot issue in software testing, because it helps developersto solve software defects effectivelyand testersto determine the regression test cases. This paper puts forward that an algorithm toanalyzethe influence domain of control flow modification. It can accurately locate the functions which are affected by modified control statements. According to the control flow function calling paths algorithm, a path of nodes is extracted, where control word as well as the function name is regarded as a node,and extract the control block and analysis it, and a static function calling path with the control logic is obtained.Control flow modificationpoint algorithm is put forward to obtain the modified control statements, which is based on Longest Common Substring (LCS) algorithm. An algorithm is also proposed to determine the influence domain of control flow modification.Experimental results show that the proposedalgorithm can determine the influence domain, and provide support for test case reduction in regression testing effectively.

Moving Object Detection with High Precision via Marked Watershed and Image Morphology

Qingqing Fu,Silin Xu,Aiping Wu 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.11

This paper presents a non-stationary object detection method by exploring time-varying spatial domain information in full motion video. Initially, the edge maps of difference image between two adjacent frames and current frame is generated via the well-known Canny edge detector. The distance of the edge pixels between the difference image and the current video frame are confined within a small value to determine the initial edge mask for the object in motion. The horizontal and vertical filling followed by morphological opening and closing operator are applied on the initial edge mask to create initial temporal segmentation mask of the moving object. The morphological dilation and corrosion operator are utilized to obtain binary marker image of the foreground and background which are used to modify the multi-scale morphological gradient image of current frame. Finally, the watershed algorithm is performed on the modified gradients to find the non-stationary objects accurately in the spatial domain of motion frames. Processed video results show detection accuracy of 98% and 99% for four different video experimentation test-beds involving fast and slow human motion. In this operation, the proposed technique eliminates the problem of over-segmentation of the watershed algorithm and extracts visually distinct, contextually meaningful non-stationary objects as they randomly appear (or disappear) in video sequences.

Fast-response thermo-sensitive actuator based on asymmetric structured PNIPAM hydrogel with inorganic particles embedding

Fan Zhuanzhuan,Weizhong Xu,Ruofei Wang,Huaping Wu,Aiping Liu 한국고분자학회 2023 Macromolecular Research Vol.31 No.6

Hydrogel actuators have potential applications in many fields because of their multiple responsiveness to environmental stimuli. However, it is still very challenging to design a hydrogel actuator with simple preparation, fast response, and good mechanical properties. In this work, a facile and convenient method to obtain a fast responsive hydrogel actuator has been successfully developed by embedding uniform inorganic particles into Poly(N-isopropylacrylamide) hydrogel network to form an asymmetric structure. By controlling the types and contents of inorganic particles, a wide range of adjustable actuation property can be achieved. At the same time, the introduction of inorganic particles greatly increases the mechanical properties of hydrogels, which is also very important for actuation performance improvement of hydrogel actuators. The optimized hydrogel exhibits relatively fast bending deformation under thermal stimulation (60 ℃), with a bending velocity of about 13.0° s−1 within first 10 s and a bending amplitude of about 328.1° within 1 min. The hydrogel can be designed to be temperature-controlled claw actuators with programmable shapes, indicating its application prospects in encapsulating, grasping, and transporting objects in water environment.

Soluble N-ethylmaleimide-sensitive Factor Attachment Receptor (SNARE) Protein Involved in the Remission of Depression by Acupuncture in Rats

Ling Fan,Zhao Chen,Wenbin Fu,Nenggui Xu,Jianhua Liu,Aiping Lu,Ziping Li,Shengyong Su,Taixiang Wu,Aihua Ou 사단법인약침학회 2016 Journal of Acupuncture & Meridian Studies Vol.9 No.5

This study aims to investigate the molecular mechanisms of acupuncture in the remission of depression. A depressive disorder model was induced by exposing Sprague–Dawley rats to chronic unpredictable stress. The rats were divided into five groups: healthy (blank group) and stressed rats (model group), and stressed rats treated with acupuncture (acupuncture group), riluzole (riluzole group), acupuncture combined with botulinum toxin A (BTX-A) injection (acupuncture+BTX-A group) or riluzole combined with BTX-A injection (riluzole+BTX-A group). Behavioral analysis showed significant differences in sucrose consumption, weight, and horizontal or vertical movements between the model and both the riluzole and acupuncture groups. No obvious differences between the riluzole+BTX-A and acupuncture+BTX-A groups were found. Moreover, no significance differences in glutamate content in the hippocampus were found among the riluzole+BTX-A, acupuncture+BTX-A and model groups (p>0.05). Western blots and reverse transcription polymerase chain reactions were employed to detect protein and mRNA expressions of VGLUT2, SNAP25, VAMP1, VAMP2, VAMP7, and syntaxin1; no obvious differences among the riluzole+BTX-A, acupuncture+BTX-A and model groups were found. These data suggest that soluble N-ethylmaleimide-sensitive factor attachment receptor proteins are involved in the remission of depression in rats treated with acupuncture.

Ultrahigh Energy Storage Capacitance and High Breakdown Strength in Biaxially Oriented Poly(vinylidene fluoride) Using a High-Electric-Induced Technique

Hongwei Lu,Jianxin Du,Cuiping Yu,Xingping Wang,Yanlin Gao,Weizhong Xu,Aiping Liu,Xiaoxiao Lu,Yingxin Chen 한국고분자학회 2020 Macromolecular Research Vol.28 No.6

The development of high dielectric materials with high energy densities is a crucial research domain in the modern microelectronics and power systems. The objective of this work was to develop the highly ordered crystal orientations and large ferroelectric crystalline β/γ-phases in the biaxially oriented poly(vinylidene fluoride) (BOPVDF). Importantly, a high discharged energy density and high dielectric constant was achieved by using a high-electric-induced technique. A suitable poling electric field was applied to the BOPVDF films in order to enhance the breakdown strength. Remarkably, the BOPVDF film poled at the electric field of 113 MV m-1 achieved an unprecedented discharged energy density of 25.4 J cm-3 at an ultra-high electric field of 550 MV m-1, which is by far the highest value ever achieved in flexible polymer-based capacitor films. Comparatively, the unpoled BOPVDF and commercial biaxially oriented polypropylene (BOPP) exhibited only a discharged energy density of 7.9 J cm-3 and 1.2 J cm-3, respectively. This systematic study provides a new design paradigm to exploit PVDF-based dielectric polymers for capacitor applications.