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Shape optimization design of a heaving buoy of wave energy converter based on fully parametric modeling and CFD method

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Journal of Hydrodynamics 2022年第6期34卷 1081-1094页

作者： Shuo Huang Wei-qi Liu Kai Wang tie-cheng Wu Tian-hui Liu School of Ocean Engineering and Technology Sun Yat-sen University&Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)Zhuhai519000China

The hydrodynamic shape of the heaving buoy is an important factor of the motion response in waves and thus concerns the energy conversion efficiency for the point absorbers(PAs).The current experience-based designs are time consuming and not very efficient,hence,faster and smarter methods are *** automated optimization method based on a fully parametric modeling method and computational fluid dynamics(CFD),is proposed in this *** this method,a benchmark buoy is screen designed and then optimized by maximizing the heave motion *** geometry is described parametrically and deformed by means of the free-form deformation(FFD)*** the optimization process,the expansion factor of control points is the basis for the variations.A combination of the Sobol and the non-dominated sorting genetic algorithm II(NSGA-II)is used to search for the *** several iterations,the heaving buoy shape with optimal heave motion response is *** analyses show that the heave motion response has increased 55.3%after *** developed methodology is valid and seems to be a promising way to design a novel buoy that can significantly improve the wave energy conversion efficiency of the PAs in future.

关键词： Wave energy converter geometric shape optimization fully parametric modeling method computational fluid dynamics(CFD)

Flow property of AA2b06 sheet using overlapping elliptical bulge test

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Transactions of Nonferrous Metals Society of China 2016年第8期26卷 2179-2187页

作者： Yao WANG tie-jun GAO Quan-da ZHANG School of Mechanical Engineering and Automation Beihang University Beijing 100191 China Collaborative Innovation Center of Advanced Aero-Engine Beihang University Beijing 100191 China Faculty of Aerospace Engineering Shenyang Aerospace University Shenyang 110136 China

A novel experimental approach was presented, namely the overlapping elliptical bulge test, which can load and research thickness normal stress. Theoretical analysis model of the overlapping elliptical bulging was described, the equivalent stress?strain curves of target sheets with different ellipticity ratios were determined experimentally, and influences of the material performance and thickness of overlapping sheets on the flow property of the target sheet were also researched. The results show that, in the overlapping hydraulic bulge test, the equivalent stress?strain curve can be determined up to larger strains before necking than in the no overlapping hydraulic bulge test. And as the die ellipticity ratio decreases, the flow stress curves tend to move away from the curve obtained by circular (b/a=1) bulging test. Meanwhile, the flow property of the target sheet can be improved by choosing higher strength coefficient K, larger work hardening exponent n and proper thickness of the overlapping sheet.

关键词： flow property aluminum alloy overlapping sheet elliptical bulge thickness normal stress

Machine learning-based performance predictions for steels considering manufacturing process parameters:a review

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Journal of Iron and Steel Research International 2024年第7期31卷 1555-1581页

作者： Wei Fang Jia-xin Huang tie-xu Peng Yang Long Fu-xing Yin Tianjin Key Laboratory of Materials Laminating Fabrication and Interface Control Technology School of Materials Science and EngineeringHebei University of TechnologyTianjin 300132China Institute of New Materials Guangdong Academy of ScienceGuangzhou 510651GuangdongChina

Steels are widely used as structural materials,making them essential for supporting our lives and ***,further improving the comprehensive properties of steel through traditional trial-and-error methods becomes challenging due to the continuous development and numerous processing parameters involved in steel *** address this challenge,the application of machine learning methods becomes crucial in establishing complex relationships between manufacturing processes and steel *** review begins with a general overview of machine learning methods and subsequently introduces various performance predictions in steel *** classification of performance pre-diction was used to assess the current application of machine learning model-assisted *** important issues,such as data source and characteristics,intermediate features,algorithm optimization,key feature analysis,and the role of environmental factors,were summarized and *** insights will be beneficial and enlightening to future research endeavors in this field.

关键词： Steel Manufacturing process Machine learning Performance prediction Algorithm

Discussion on the extended form of internal solitary wave models between two typical stratification systems

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Journal of Hydrodynamics 2023年第1期35卷 155-170页

作者： Jiu-ming Zhang Li Zou tie-zhi Sun Zong-bing Yu Hao Wang School of Naval Architecture State Key Laboratory of Structural Analysis for Industrial EquipmentDalian University of TechnologyDalian116024China Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration Shanghai200240China Institute of Hydrology&Water Resources Tsinghua UniversityBeijing100084China China Institute of Water Resources and Hydropower Research Beijing100038China

The two-layer fluid system and the continuous density system are based on two typical simplified stratification conditions to support the propagation of the internal solitary waves(ISWs).The aim of this study is to establish several extension methods of the classical ISW models across the stratification systems in an attempt to find a simple ISW structure that can propagate more stably,and to determine whether the stable ISW structure in the two typical stratification systems can be expressed in terms of a consistent nonlinear *** the constructed ISW structures,the propagation stability has been investigated by taking the Euler equations as the evolution *** results show that the ISW structure constructed from the Miyata-Choi-Camassa(MCC)model undergoes two stages of instability and the re-stable ISW has a larger available potential energy and a smaller kinetic energy than the initialized *** illustrates the limitation of the weakly dispersive assumption in the MCC *** contrast,the ISW structure constructed from the Dubreil-Jacotin-Long(DJL)model for the two-layer fluid system is generally stable,due to the fact that the boussinesq approximation introduced in the derivation of the DJL model will be automatically satisfied in this *** initial condition interpolated from the DJL model with a thin pycnocline thickness can be regarded as an appropriate ISW structure for the two-layer system and is even more stable than that initialized by the MCC *** addition,the effect of the boussinesq approximation is also included in the *** approximation can be considered equivalent to a weakly dispersive assumption and should not be ignored for the ISW problem in the continuous density system.

关键词： Internal solitary wave stratification condition the Miyata-Choi-Camassa(MCC)model the Dubreil-Jacotin-Long(DJL)equation boussinesq approximation

FeNi doped porous carbon as an efficient catalyst for oxygen evolution reaction

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Frontiers of Chemical Science and Engineering 2021年第2期15卷 279-287页

作者： Jun-Wei Zhang Hang Zhang tie-Zhen Ren Zhong-Yong Yuan Teresa Jbandosz Hebei Provincial Key Laboratory of Green Chemical Technology&High Efficient Energy Saving School of Chemical Engineering and TechnologyHebei University of TechnologyTianjin 300130China Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education) School of Materials Science and EngineeringNankai UniversityTianjin 300350China Department of Chemistry and biochemistry The City College of New YorkNew YorkNY 10031USA

Polymer-derived porous carbon was used as a support of iron and nickel species with an objective to obtain an efficient oxygen reduction reaction(OER)*** surface features were extensively characterized using X-ray diffraction,X-ray photoelectron spectroscopy and high-resolution transmission electron *** FeNi-modified carbon the overpotential for OER was very low(280 mV)and comparable to that on noble metal catalyst IrO_(2).The electrochemical properties have been investigated to reveal the difference between the binary alloy-and single metal-doped *** work demonstrates a significant step for the development of low-cost,environmentally-friendly and highly-efficient OER catalysts.

关键词： OER polystyrene salt porous carbon FeNi alloy p/n junction

Short-gate AlGaN/GaN high-electron mobility transistors with bGaN buffer

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Chinese Physics b 2019年第4期28卷 326-331页

作者： tie-Cheng Han Hong-Dong Zhao Xiao-Can Peng School of Electronic and Information Engineering Hebei University of Technology

Using the semi-insulating property and small lattice constant a of wurtzite bGaN alloy, we propose a bGaN buffer with a b-content of 1% to enhance two-dimensional electron gas(2 DEG) confinement in a short-gate AlGaN/GaN highelectron mobility transistor(HEMT). based on the two-dimensional TCAD simulation, the direct current(DC) and radio frequency(RF) characteristics of the AlGaN/GaN/b_(0.01)Ga_(0.99)N structure HEMTs are theoretically studied. Our results show that the bGaN buffer device achieves good pinch-off quality and improves RF performance compared with GaN buffer device. The bGaN buffer device can allow a good immunity to shift of threshold voltage for the aspect ratio(LG/d)down to 6, which is much lower than that the GaN buffer device with L_G/d=11 can reach. Furthermore, due to a similar manner of enhancing 2 DEG confinement, the b_(0.01)Ga_(0.99)N buffer device has similar DC and RF characteristics to those the AlGaN buffer device possesses, and its ability to control short-channel effects(SCEs) is comparable to that of an Al_(0.03)Ga_(0.97)N buffer. Therefore, this bGaN buffer with very small b-content promises to be a new method to suppress SCEs in GaN HEMTs.

关键词： AlGaN/GaN HEMT bGaN back barrier short-channel effects(SCEs)

Probability Prediction Model for Landslide Occurrences in Xi'an, Shaanxi Province, China

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Journal of Mountain Science 2014年第2期11卷 345-359页

作者： ZHUANG Jian-qi IQbAL Javed PENG Jian-bing LIU tie-ming College of Geological Engineering and Surveying of Changan University/Key Laboratory of Western China Mineral Resources and Geological Engineering Department of Earth Sciences COMSATS Institute of Information Technology Institute of Geology and Geophysics Chinese Academy of Sciences Geo-hazards Mitigation and Research of Chang'an University

Landslides are increasing since the 1980s in Xi'an, Shaanxi Province, China. This is due to the increase of the frequency and intensity of precipitation caused by complex geological structures, the presence of steep landforms, seasonal heavy rainfall, and the intensifcation of human activities. In this study, we propose a landslide prediction model based on the analysis of intraday rainfall(IR) and antecedent effective rainfall(AER). Primarily, the number of days and degressive index of the antecedent effective rainfall which affected landslide occurrences in the areas around Qin Mountains, Li Mountains and Loess Tableland was established. Secondly, the antecedent effective rainfall and intraday rainfall were calculated from weather data which were used to construct critical thresholds for the 10%, 50% and 90% probabilities for future landslide occurrences in Qin Mountain, Li Mountain and Loess Tableland. Finally, the regions corresponding to different warning levels were identified based on the relationship between precipitation and the threshold, that is; "A" region is safe, "b" region is on watch alert, "C" region is on warning alert and "D" region is on severe warning alert. Using this model, a warning program is proposed which can predict rainfall-induced landslides by means of real-time rain gauge data and real-time geo-hazard alert and disaster response programs. Sixteen rain gauges were installed in the Xi'an region by keeping in accordance with the regional geology and landslide risks. based on the data from gauges, this model accurately achieves the objectives of conducting real-time monitoring as well as providing early warnings of landslides in the Xi'an region.

关键词： Landslide Probability prediction model Real-time monitoring Xi'an

Physiological basis for the differences of productive capacity among tillers in winter wheat

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Journal of Integrative Agriculture 2015年第10期14卷 1958-1970页

作者： XU Hai-cheng CAI tie WANG Zhen-lin HE Ming-rong National Key Laboratory of Crop biology Ministry of Science and Technology/Agronomy College Shandong Agricultural University Institute of Water-Saving Agriculture in Arid Areas of China Agronomy College Northwest A&F University

The quality or structure of a wheat population is significantly affected by the compositions of tillers. Little has been known about the physiological basis for the differences of productive capacity among tillers. Two winter wheat cultivars, Shannong 15（SN15） and Shannong 8355（SN8355）, were used to investigate the differences of productive capacity among tillers and analyze the physiological mechanisms that determine the superior tiller group. Low-position tillers（early initiated tillers） had a higher yield per spike than high-position tillers（late initiated tillers） in both cultivars, which was due to their more grain number per spike, more fertile spikelet per spike, less sterile spikelet per spike and higher grain weight. According to cluster analysis, tillers of SN15 were classified into 2 groups： superior tiller group including main stem（0）, the first primary tiller（I） and the second primary tiller（II）; and inferior tiller group including the third primary tiller（III） and the first secondary tiller（I-p）. Tillers of SN8355 were classified into 3 groups： superior tiller group（0 and I）, intermediate tiller group（II and III） and inferior tiller group（I-p）. In comparison with other tiller groups, the superior tiller group had higher photosynthetic rate of flag leaves, higher antioxidant enzyme（SOD, POD and CAT） activities and lower levels of lipid peroxidation in leaves, higher grain filling rate in both superior and inferior grains during grain filling, higher single-stem biological yield and larger single-stem economic coefficient. Correlation analysis showed that yield per spike was positively and significantly correlated with the flag leaf photosynthetic rate, grain filling rate, the antioxidant enzyme activities and soluble protein content（except for SN15 at 5 days post-anthesis（DPA）） of flag leaf, the single-stem biological yield, and the single-stem economic coefficient. Remarkable negative correlation was also found between yield per spike and MDA content o

关键词： enzyme activities grain filling photosynthetic rate productive capacity tillers wheat(Triticum aestivum L.)

Identification of proteinaceous binding media for the polychrome terracotta army of Emperor Qin Shihuang by MALDI-TOF-MS

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Chinese Science bulletin 2014年第21期59卷 2574-2581页

作者： Hongtao Yan Jingjing An tie Zhou Yin Xia bo Rong College of Chemistry and Materials Science Northwest University Key Scientific Research base of Ancient Polychrome Pottery Conservation State Administration for Cultural Heritage Museum of Emperor Qin Shihuang’s Terracotta Army

A proteinaceous binding media for the polychrome terracotta army of Emperor Qin Shihuang has been identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF-MS).Methods for the preparation of the model samples and the elimination of interferences have been evaluated,as well as ageing processes.A method involving the complexation of EDTA in combination with dialysis was used to eliminate any interference in the polychrome layers taken from the historical *** model samples were aged by being buried in loess to replicate the ageing process of the historical samples as closely as *** optimum conditions for the extraction and subsequent enzymatic hydrolysis of the extracted protein were *** the optimized conditions,the‘‘peptide mass fingerprints’’of the proteinaceous binding media from the historical and model samples were determined by *** results revealed that animal glue was used as the binding media for the polychrome layers of Emperor Qin Shihuang’s terracotta *** also shows that animal glue used as binding media has a long history in China.

关键词： MALDI-TOF-MS 蛋白质兵马俑秦始皇媒体基质辅助激光解吸肽质量指纹图谱多色