Numerical prediction analysis of propeller exciting force for hullepropellererudder system in oblique flow

Shuai Sun,Liang Li,Chao Wang,Hongyu Zhang 대한조선학회 2018 International Journal of Naval Architecture and Oc Vol.10 No.1

In order to analyze the characteristics of propeller exciting force, the hybrid grid is adopted and the numerical prediction of KCS ship model is performed for hullepropellererudder system by Reynolds-Averaged Navier Stokes (RANS) method and volume of fluid (VOF) model. Firstly, the numerical simulation of hydrodynamics for bare hull at oblique state is carried out. The results show that with the increasing of the drift angle, the coefficients of resistance, side force and yaw moment are constantly increasing, and the bigger the drift angle, the worse the overall uniformity of propeller disk. Then, propeller bearing force for hullepropellererudder system in oblique flow is calculated. It is found that the propeller thrust and torque fluctuation coefficient peak in drift angle are greater than that in straight line navigation, and the negative drift angle is greater than the positive. The fluctuation peak variation law of coefficient of side force and bending moment are different due to various causes.

Protein-based soft micro-optics fabricated by femtosecond laser direct writing

Sun, Yun-Lu,Dong, Wen-Fei,Niu, Li-Gang,Jiang, Tong,Liu, Dong-Xu,Zhang, Lu,Wang, Ying-Shuai,Chen, Qi-Dai,Kim, Dong-Pyo,Sun, Hong-Bo Nature Publishing Group 2014 Light, science & applications Vol.3 No.1

<P>In this work, we report a novel soft diffractive micro-optics, called 'microscale kinoform phase-type lens (micro-KPL)', which is fabricated by femtosecond laser direct writing (FsLDW) using bovine serum albumin (BSA) as building blocks and flexible polydimethylsiloxane (PDMS) slices as substrates. By carefully optimizing various process parameters of FsLDW (e. g., average laser power density, scanning step, exposure time on a single point and protein concentration), the as-formed protein micro-KPLs exhibit excellent surface quality, well-defined three-dimensional (3D) geometry and distinctive optical properties, even in relatively harsh operation environments (for instance, in strong acid or base). Laser shaping, imaging and other optical performances can be easily achieved. More importantly, micro-KPLs also have unique flexible and stretchable properties as well as good biocompatibility and biodegradability. Therefore, such protein hydrogel-based micro-optics may have great potential applications, such as in flexible and stretchable photonics and optics, soft integrated optical microsystems and bioimplantable devices.</P>

Numerical prediction analysis of propeller exciting force for hull-propeller-rudder system in oblique flow

Sun, Shuai,Li, Liang,Wang, Chao,Zhang, Hongyu The Society of Naval Architects of Korea 2018 International Journal of Naval Architecture and Oc Vol.10 No.1

In order to analyze the characteristics of propeller exciting force, the hybrid grid is adopted and the numerical prediction of KCS ship model is performed for hull-propeller-rudder system by Reynolds-Averaged Navier Stokes (RANS) method and volume of fluid (VOF) model. Firstly, the numerical simulation of hydrodynamics for bare hull at oblique state is carried out. The results show that with the increasing of the drift angle, the coefficients of resistance, side force and yaw moment are constantly increasing, and the bigger the drift angle, the worse the overall uniformity of propeller disk. Then, propeller bearing force for hull-propeller-rudder system in oblique flow is calculated. It is found that the propeller thrust and torque fluctuation coefficient peak in drift angle are greater than that in straight line navigation, and the negative drift angle is greater than the positive. The fluctuation peak variation law of coefficient of side force and bending moment are different due to various causes.

Simple Joule-heating pyrolysis in air boosts capacitive performance of commercial carbon fiber cloth

Sun Xiaohao,Hou Shuai,Yuan Lan,Guo Fen 한국탄소학회 2022 Carbon Letters Vol.32 No.7

Commercial carbon fiber cloth (CFC) is treated by the Joule-heating pyrolysis method in air to boost its capacitive performance on the premise of energy- and time-saving considerations. A thermoelectric coupling model suitable for the Joule-heating pyrolysis is successfully established based on the comparisons between the simulated temperatures and actually measured ones. The temperature field on CFC surface induced by the Joule heat presents a concentric-ellipse shape that the temperature in the core is the maximal and gradually decays outward. Increasing the direct current (DC) voltage which is applied to the CFC from 1.0 to 6.0 V, the core temperature on the CFC surface can be raised from 31 to 519 °C. The specific surface area and hydrophilicity of the as-prepared porous CFC are greatly improved compared with the pristine one. Electrochemical test shows that the optimal Joule-heating pyrolysis parameters falls at 5.0 V and 12.5 min, and the areal specific capacitance of as-obtained CFC-5.0-12.5 is about 80 folds that of the pristine CFC. In addition to the much shorter preparation time, all the characteristics including areal specific capacitance, rate performance, and electrical conductivity of the Joule-heating pyrolyzed CFC are superior to those of the electrical furnace pyrolyzed counterpart. The aqueous symmetrical supercapacitor made of CFC-5.0-12.5 electrodes exhibits considerable power and energy densities with respect to the previously reported carbon electrode-based supercapacitors. For conductive precursors, the Joule-heating pyrolysis can be an ideal substitute for the traditional electric furnace pyrolysis.

Visual Tracking with Online Incremental Deep Learning and Particle Filter

Shuai Cheng,Yonggang Cao,Junxi Sun,Guangwen Liu 보안공학연구지원센터 2015 International Journal of Signal Processing, Image Vol.8 No.12

To solve the problem of tracking the trajectory of a moving object and learning a deep compact image representation in the complex environment, a novel robust incremental deep learning tracker is presented under the particle filter framework. The incremental deep classification neural network was composed of stacked denoising autoencoder, incremental feature learning and support vector machine to achieve the feature-extracting and classification of particle set. Deep learning is successfully taken to express the image representations obtained effectively. Unsupervised feature learning is used to learn generic image features and transfer learning transforms knowledge from offline training to the online tracking process. The incremental feature learning was consisted of adding features and merging features to online learn compact feature set. Linear support vector machine increases the discretion for target with similar appearance and is further tuned to adapt to appearance changes of the moving object. Compared with the state-of-the-art trackers in the complex environment, the results of experiments on variant challenging image sequences show that incremental deep learning tracker solves the problem of existent trackers more efficiently, it has better robust and more accurate, especially for occlusions, background clutter, illumination changes and appearance changes.

GaN nanorods gas sensor for highly sensitive n-butanol detection at room temperature

Shuai Han,Yongming Fu,Donghui Li,Dan Han,Qinjun Sun 대한금속·재료학회 2023 ELECTRONIC MATERIALS LETTERS Vol.19 No.3

Safe and effi cient detection of hazardous n-butanol gas is very great signifi cance to the health of workers and researchers inchemical environments. In this work, we successfully developed a GaN gas sensor by a simple solvothermal method and alow-temperature nitridation process. Material characterization results show that one-dimensional nanorods structures wereobtained and the products presented a superior growth orientation along with (101) plane. The gas sensing test results showthat the sensor exhibits excellent responsivity, repeatability, and selectivity to n-butanol at room temperature. The responseand recovery time of the sensor to 200 ppm n-butanol gas was 45 s/34 s. Gas adsorption model and electron depletion layertheory were established to understand the n-butanol sensing mechanism. This work provides the possibility for its realapplication in n-butanol detection with safe and effi cient at room temperature.

China's Brain Gain at the High End: An Assessment of Thousand Youth Talents Program

Sun, Yutao,Guo, Rongyu,Zhang, Shuai Asian Society for Innovation and Policy 2017 Asian Journal of Innovation and Policy Vol.6 No.3

While studies have viewed the effect of Chinese talent-attracting programs launched by government since reform and open door policy, little of them has assessed these programs empirically and pertinently. This article intends to assess an important program - the Thousand Youth Talents Program (TYTP). Frist, this paper proposed a transnational migration matrix of the academics to clarify the dynamic mechanism of academic brain gain at the high end. Then, the Kaplan-Meier analysis and Cox regression model are used to empirically analyze the policy effect of TYTP. The results show that, academic ability have double edged impacts on brain gain at the high end, some scholars whose last employer's academic ranking is world's Top100 have stronger willing to return, and the negative effect of academic ranking decreases with time passing; while scholars with a tenure-track position, a tenure position or a permanent position tend to stay overseas, and the hazard rate of staying increases with age. The older scholars have more intentions to go back China, while gender was not a significant factor influencing academic return at the high end. That is, the talent-attracting programs has partly succeeded in bringing back the academics at the high end.

Synthesis of N-Azaaryl Anilines: An Efficient Protocol via Smiles Rearrangement

Shuai Xia,Li-Ying Wang,Heng-Zhi Sun,Huan Yue,Xiu-Hua Wang,Jia-Lian Tan,Yin Wang,Di Hou,Xiao-Yan He,Ki-Cheol Mun,B. Prem kumar,Hua Zuo,신동수 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.2

An efficient process for the synthesis of N-azaaryl anilines via Smiles rearrangement as a tool. A variety of Nazaaryl anilines were generated by the reaction of substituted phenols, substituted anilines, aminopyridines and chloroacetyl chloride or pyridols, under base condition in good to excellent yields.

Secure Communication based on a Fractional Order Chaotic System

Shuai Wang,Wei Sun,Cao-Yuan Ma,Di Wang,Zheng-Chen 보안공학연구지원센터 2013 International Journal of Security and Its Applicat Vol.7 No.5

Effects of sludge pyrolysis temperature and atmosphere on characteristics of biochar and gaseous products

Shuai Guo,Xiaoyan Xiong,Deyong Che,Hongpeng Liu,Baizhong Sun 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.1

In view of the importance of inert-atmosphere sludge pyrolysis for effective waste recycling and carbon emission reduction, this study probed the effects of temperature (300-700 oC) and atmosphere (100% N2, 10 CO2/90% N2, or 100% CO2) on the properties of biochar and gases obtained by sludge pyrolysis in a horizontal tube furnace. The emissions of NO, SO2, H2S, and CO increased with increasing temperature, as the inhibitory effect of CO2 on the formation of these gases (observed at <500 oC) concomitantly weakened and was superseded by the reaction of CO2 with carbon at higher temperature to afford gaseous products. The specific surface area (SBET) and pore volume of the biochar produced in the presence of CO2 increased with increasing temperature up to 500 oC, while at higher temperatures the inhibitory effect of CO2 on pore structure development resulted in a decreased SBET and an increased macropore content. These results show that pyrolysis is an effective treatment method for sludge; it can remove 48% N and 50% S in sludge and mitigate the emission of polluting gases. When CO2 participates in the pyrolysis reaction, the SBET of biochar increases significantly. In general, sludge biochar has the potential to be applied as fuel and as an adsorbent.