Single-crystalline tungsten oxide nanoplates

Deliang Chen,Hailong Wang,Rui Zhang,Lian Gao,Yoshiyuki Sugahara,Atsuo Yasumori 한양대학교 세라믹연구소 2008 Journal of Ceramic Processing Research Vol.9 No.6

Tungsten oxide nanocrystals are important semiconductor materials with a suitable energy band gap (ca. 2.5 eV) for visible-light utilization. Though there are a great amount of reports on the synthesis of WO3 nanocrystals, no effective routes to two-dimensional (2D) WO3 nanocrystals have been reported. We here developed a novel and efficient route to synthesize free-standing single-crystalline WO3 nanoplates on a large scale and in a repeatable way. The proposed route involved a rational transformation of tungstatebased inorganic-organic hybrid nanobelts to single-crystalline WO3·H2O nanoplates, and then to single-crystalline monoclinic WO3 nanoplates with an inhibited crystal growth direction of [004]. The sizes of the as-obtained WO3 nanoplates are (200-500) nm × (200-500) nm × (10-30) nm. The WO3 nanoplates as-synthesized have high specific surface areas (up to 180m2 g−1) and showed remarkably enhanced visible-light photocatalytic properties in water splitting for O2 generation. Tungsten oxide nanocrystals are important semiconductor materials with a suitable energy band gap (ca. 2.5 eV) for visible-light utilization. Though there are a great amount of reports on the synthesis of WO3 nanocrystals, no effective routes to two-dimensional (2D) WO3 nanocrystals have been reported. We here developed a novel and efficient route to synthesize free-standing single-crystalline WO3 nanoplates on a large scale and in a repeatable way. The proposed route involved a rational transformation of tungstatebased inorganic-organic hybrid nanobelts to single-crystalline WO3·H2O nanoplates, and then to single-crystalline monoclinic WO3 nanoplates with an inhibited crystal growth direction of [004]. The sizes of the as-obtained WO3 nanoplates are (200-500) nm × (200-500) nm × (10-30) nm. The WO3 nanoplates as-synthesized have high specific surface areas (up to 180m2 g−1) and showed remarkably enhanced visible-light photocatalytic properties in water splitting for O2 generation.

Random Field Model of Corroded Steel Plate Surface in Neutral Salt Spray Environment

Kong Deliang,Nie Biao,Xu Shanhua 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.7

The random field model of corrosion depth on steel plate surface in neutral salt spray environment was investigated. 10 groups of specimens were subjected to accelerate corrosion by the neutral salt spray test, and the surface profile of corroded steel plates and the 3D data of corrosion depth were measured by three-dimensional non-contact surface topography instrument. The probability characteristics of corrosion depth were studied and the relationship between the average and the standard deviation of corrosion depth and the mass loss rate were analyzed. The corrosion depth were tested for ergodicity and stationarity and the autocorrelation function model of random field model of corrosiondepth was proposed. The results of the study show that the corrosion depth on steel plate surface in neutral salt spray environment conformed to the normal distribution. With the increase of mass loss rate, the average and the standard deviation of the corrosion depth increased. The corrosion depth has ergodicity and stationarity. The random field model of cosine trigonometric function can accurately characterize the distribution of corrosion depth, which prepared the preliminary preparation for the finite element analysis of the corroded steel structure.

A Review of Information Seeking Behavior

Hong Jin,Deliang Zhu ASCONS 2020 INTERNATIONAL JOURNAL OF EMERGING MULTIDISCIPLINAR Vol.4 No.4

Background/Objectives: This article sorts out the literatures of traditional information seeking behavior and social information seeking and looks ahead the research direction of information seeking behavior. Methods/Statistical analysis: This study is a study conducted based on previous studies. That is, it is a review paper. Findings: Based on the results obtained from previous studies, it came to the conclusion that more studies on information seeking behavior are needed. Improvements/Applications: The influence of cognitive factors on social information seeking is rare, and the social information seeking model requires a study that fully considers the effects of cognitive factors.

Multi‑amplitude voltage vector MPTC for dual three‑phase PMSMs with low torque ripple

Shuang Wang,Qianru Zhang,Deliang Wu,Jianfei Zhao 전력전자학회 2024 JOURNAL OF POWER ELECTRONICS Vol.24 No.1

In model predictive torque control (MPTC), voltage vectors with a fixed amplitude have poor performance in torque tracking. In this paper, a multi-amplitude MPTC (MA-MPTC) method for dual three-phase permanent magnet synchronous motor (PMSM) is proposed, which can effectively reduce torque ripple by combining virtual voltage vectors (VVVs) and actual voltage vectors (AVVs). First, the deadbeat (DB) technique is used to simplify voltage vector selection and to avoid the enumeration of all the possible voltage vectors. After calculating the reference voltage vector (RVV) using this method, four vectors with different amplitudes can be selected as candidate voltage vectors (CVVs) according to the angle of the RVV. Then a new cost function is used to calculate the four candidate vectors, and the vector that minimizes the cost function is the optimal vector. Therefore, the MA-MPTC strategy has the advantages of both the MPTC method and the DB method, which can effectively reduce the torque ripple with a low computational cost. In addition, VVVs are used to reduce the influence of harmonic currents while suppressing torque ripple. Finally, the stability and dynamic response are investigated on the test bench. When compared with a contrast method, the torque ripple is reduced by nearly half and the advantage of fast response is maintained. The experimental results confirm the effectiveness of the proposed method.

Evaluation of global climate models in simulating extreme precipitation in China

Ou, Tinghai,Chen, Deliang,Linderholm, Hans W.,Jeong, Jee-Hoon Co-Action Publishing 2013 Tellus. Series A, Dynamic meteorology and oceanogr Vol.65 No.1

Fabrication of TiAl Target by Mechanical Alloying and Applications in Physical Vapour Deposition Coating

Gabbitas Brian,Cao Peng,Raynova Stiliana,Zhang Deliang 한국분말야금학회 2006 한국분말야금학회 학술대회논문집 Vol.2006 No.1

The research involves the development of a powder metallurgical route for producing good quality TiAl targets for making physical vapour deposition (PVD) coatings. Mixtures of elemental titanium and aluminium powders were mechanically milled using a novel discus milling technique under various conditions. Hot isotropic pressing (HIP) was then employed for consolidation of the mechanically alloyed powders. A cathodic arc vapour deposition process was applied to produce a TiAlN coating. Microstructural examination was conducted on the target material and PVD coatings, using X-ray diffractometry (XRD), X-ray photoelectron spectrometry (XPS) and scanning electron microscopy (SEM). It has been found that combining mechanical alloying and HIP enable us to produce fairly good quality of TiAl based target. The PVD coatings obtained from the TiAl target showed very high microhardness values.

Tropical cyclone rainfall in the Mekong River Basin for 1983–2016

Chen, Aifang,Ho, Chang-Hoi,Chen, Deliang,Azorin-Molina, Cesar Elsevier 2019 Atmospheric research Vol.226 No.-

<P><B>Abstract</B></P> <P>As home to about 70 million people, the Mekong River Basin (MRB), located in Mainland Southeast Asia, is often influenced by tropical cyclones (TCs) landfalling. The TCs not only cause flood and storm hazards, but also play important roles in providing freshwater resource and welcomed sediment transports. Our study focuses on the climatology of TCs and associated rainfall (TCR) in the MRB for 1983–2016. Results show that: (i) the mean landfall occurrence of TCs is 6.2 yr<SUP>−1</SUP>, leading to 36.7 mm yr<SUP>−1</SUP> of annual mean TCR (2.5% of the annual total precipitation), which mainly occur in monsoon-TC season (i.e., June–November); (ii) TCs highly concentrate on the lower eastern MRB, generating the largest TCR contribution of 12.4% to the annual total precipitation; (iii) the annual mean contribution of TCs induced extreme precipitation - R20mm and R50mm (days of heavy precipitation rate ≥20 mm day<SUP>−1</SUP> and ≥50 mm day<SUP>−1</SUP>, respectively) - to that from annual total precipitation is large in the lower eastern MRB; (iv) over 60% of the basin area is influenced by TCR on average; and (v) a significant weakening trend of the TC frequency has been observed. The present findings lay a foundation for further in-depth research of the potential influence of the dynamic TCs and the associated rainfall in the MRB.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Annual mean tropical cyclone landfall is 6.2 yr<SUP>−1</SUP> in the Mekong River Basin. </LI> <LI> Annual mean tropical cyclone rainfall contributes to 2.5% of annual total precipitation. </LI> <LI> Tropical cyclone highly concentrates on the lower eastern basin. </LI> <LI> Tropical cyclone contributes largely to extreme precipitation. </LI> <LI> A significant weakening trend of tropical cyclone occurrences is observed. </LI> </UL> </P>

Transient response of a piezoelectric layer with a penny-shaped crack under electromechanical impacts

Feng, Wenjie,Li, Yansong,Ren, DeLiang Techno-Press 2006 Structural Engineering and Mechanics, An Int'l Jou Vol.23 No.2

In this paper, the dynamic response of a piezoelectric layer with a penny-shaped crack is investigated. The piezoelectric layer is subjected to an axisymmetrical action of both mechanical and electrical impacts. Two kinds of crack surface conditions, i.e., electrically impermeable and electrically permeable, are adopted. Based upon integral transform technique, the crack boundary value problem is reduced to a system of Fredholm integral equations in the Laplace transform domain. By making use of numerical Laplace inversion the time-dependent dynamic stress and electric displacement intensity factors are obtained, and the dynamic energy release rate is further derived. Numerical results are plotted to show the effects of both the piezoelectric layer thickness and the electrical impact loadings on the dynamic fracture behaviors of the crack tips.

Unmanned Aerial Vehicle Targeting Based on Image Matching

Zhang Yan,Li Jianzeng,Li Deliang,Zhou Zidong,Du Yulong,Ji Weidong 보안공학연구지원센터 2016 International Journal of Multimedia and Ubiquitous Vol.11 No.1

Aiming at the problem of low accuracy of the target for one UAV (Unmanned Aerial Vehicle), an UAV target location method based on image matching is presented according to the data of video and photograph as well as the information of the digital map. Firstly, using the improved artificial matching method, the UAV aerial images are jointed based on the digital map to obtain the coordinates information. Then, the UAV video frame resolution containing the target is improved by the improving method of super-resolution reconstruction. Finally, making use of the improved SIFT algorithm, the video frames are registered with the aerial photo to complete the location of the target. Results prove that this method can achieve the target location without the UAV’s position and attitude information, while improving the precision and speed of target location, this method is an effective one for target location based on the image matching in the battlefield.

Fabrication of Powder Feedstock for Thermal Spraying and Evaluation of the Composite Coating

Cao Peng,Gabbitas Brian,Zheng Ling,Zhang Deliang 한국분말야금학회 2006 한국분말야금학회 학술대회논문집 Vol.2006 No.1

[ ] composite powders were produced by high energy mechanical milling of a mixture of Al and powders followed by a combustion reaction. The powders were subsequently thermally sprayed on H13 steel substrates. Microstructural examination was conducted on the composite powders and thermally sprayed coatings, using X-ray diffractometry (XRD) and scanning electron microscopy (SEM). The performance of the coatings was evaluated in terms of micro-hardness and thermal fatigue. The thermally sprayed coatings performed very well in the preliminary thermal fatigue tests and showed no wetting tendency to molten aluminum.