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Effects of process parameters on surface quality,composition segregation,microstructure and properties of QSn6.5-0.1 alloy slabs fabricated by HCCM horizontal continuous casting

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Journal of Iron and Steel Research International 2017年第3期24卷 273-281页

作者： Yang Liu Xin-hua Liu hua-dong fu Min-xuan Lou jian-xin Xie Institute for Advanced Materials and Technology University of Science and Technology Beijing Beijing 100083 China

Columnar-grained QSn6. 5-0. 1 alloy slabs with a width of 70 mm and thickness of 10 mm were fabricated by heating-cooling combined mold（ HCCM） horizontal continuous casting. The effects of process parameters on solidification microstructure,surface quality,composition segregation and mechanical properties were studied. The results showed that the slabs with good surface quality,excellent mechanical properties and no obvious segregation could be prepared at the melt casting temperature of 1 250 ℃,the heating-mold temperature of 1 150- 1 200℃,the cooling water flow rate of 600 L / h and the casting speed of 20- 80 mm / min. The slabs had the yield strength of 124- 155 MPa,the elongation rate of 46. 6%- 56. 3% and the surface roughness of 0. 22- 0. 55μm,which enabled them to be directly processed without subsequent milling surface. The ratio of Sn content in the surface to that in the core was 0. 83- 1. 10,with an average value close to 1. 0,and not obviously influenced by process parameters. When the casting speed increased from 20 to 80 mm / min,the grain size changed little if the other process parameters were the same. When the heating-mold temperature increased from 1 150 to 1 200℃,the grain size was obviously refined and became more uniform if the casting speed was the same. Within the range of the casting speed at which the columnar grain structure could be obtained,the columnar grain size was mainly influenced by the heating-mold temperature.

关键词： QSn6.5 copper alloy Heating-cooling combined mold Horizontal continuous casting Microstructure Mechanical property Composition segregation

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Numerical analysis of turbulent fluctuations around an axisymmetric body of revolution based on wall-modeled large eddy simulations

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Journal of Hydrodynamics 2023年第6期35卷 1041-1051页

作者： Kang-jian He fu-chang Zhou Wei-wen Zhao jian-hua Wang De-cheng Wan Computational Marine Hydrodynamics Lab(CMHL) School of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China Wuhan Second Ship Design and Research Institute Wuhan430205China

Wall-modeled large eddy simulation(WMLES)is used to investigate turbulent fluctuations around an axisymmetric body of *** study focuses on evaluating the ability of WMLES to predict the fluctuating flow over the axisymmetric hull and analyzing the evolution of turbulent fluctuations around the *** geometry is the DARPA SUBOFF bare model and the Reynolds number is 1.2×10^(7),based on the free-stream velocity and the length of the ***-wall flow structures and complex turbulent fluctuation fields are successfully ***-averaged flow quantities,such as time-averaged pressure and skin-friction coefficients,and time-averaged velocity profiles on the stern,achieved great agreements between WMLES results and experimental ***-similarity of time-averaged velocity defects within a self-similar coordinate up to twelve diameters from the tail.A comprehensive analysis of second-order statistics in the mid-body,stern,and wake regions is *** results agree well with experimental data and previous wall-resolved large eddy simulation(WRLES)results about root mean square(rms)of radial and axial fluctuating velocities at the *** fluctuations including turbulent kinetic energy(TKE)and second-order velocity statistics are identified as dual peak behavior and non-self-similar over the wake length,consistent with previous findings in the *** assessment enhances the understanding of WMLES capabilities in capturing complex fluctuating flow around axisymmetric geometries.

关键词： Turbulent fluctuations wall-modeled large eddy simulation(WMLES) turbulent boundary layer wake

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Growth and Major Nutrient Concentrations in Brassica campestris Supplied with Different NH4^＋/NO3 Ratios

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Journal of Integrative Plant Biology 2007年第4期49卷 455-462页

作者： fu-Cang Zhang Shao-Zhong Kang fu-Sheng Li jian-hua Zhang Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas of Ministry of Education Northwest A & F University Yangling 712100 China College of Water Resources and Civil Engineering China Agricultural University Beijing 100083 China College of Agriculture Guangxi University Nanning 530005 China Department of Biology Hong Kong Baptist University Hong Kong SAR China

In the present study, we investigated whether growth and main nutrient ion concentrations of cabbage （Brassica campestris L.） could be increased when plants were subjected to different NH4^＋/NO3- ratios. Cabbage seedlings were grown in a greenhouse in nutrient solutions with five NH4^＋/NO3- ratios （1：0; 0.75：0.25; 0.5：0.5; 0.25：0.75; and 0：1）. The results showed that cabbage growth was reduced by 87% when the proportion of NH4^＋-N in the nutrient solution was more than 75% compared with a ratio NH4^＋/NO3- of 0.5：0.5 35 d after transplanting, suggesting a possible toxicity due to the accumulation of a large amount of free ammonia in the leaves. When the NH4＋/NO3- ratio was 0.5：0.5, fresh seedling weight, root length, and H2PO4- （P）, K^＋, Ca^2＋, and Mg^2＋ concentrations were all higher than those in plants grown under other NH4^＋/NO3- ratios. The nitrate concentration in the leaves was the lowest in plants grown at 0.5： 0.5 NH4^＋/NO3-. The present results indicate that an appropriate NH4^＋/NO3- ratio improves the absorption of other nutrients and maintains a suitable proportion of N assimilation and storage that should benefit plant growth and the quality of cabbage as a vegetable.

关键词： cabbage (Brassica campestris), N nutrition NH4^+/NO3- ratio plant growth plant nutrition.

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Automated process parameters tuning for an injection moulding machine with soft computing

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2011年第3期12卷 201-206页

作者： Peng ZHAO jian-zhong fu hua-min ZHOU Shu-biao CUI State Key Laboratory of Fluid Power Transmission and Control Zhejiang University Hangzhou 310027 China State Key Laboratory of Material Processing and Die & Mould Technology Huazhong University of Science and Technology Wuhan 430074 China

In injection moulding production,the tuning of the process parameters is a challenging job,which relies heavily on the experience of skilled *** this paper,taking into consideration operator assessment during moulding trials,a novel intelligent model for automated tuning of process parameters is *** consists of case based reasoning (CBR),empirical model (EM),and fuzzy logic (FL) *** and EM are used to imitate recall and intuitive thoughts of skilled operators,respectively,while FL is adopted to simulate the skilled operator optimization ***,CBR is used to set up the initial process *** CBR fails,EM is employed to calculate the initial ***,a moulding trial is performed using the initial *** FL is adopted to optimize these parameters and correct defects repeatedly until the moulded part is found to be *** on the above methodologies,intelligent software was developed and embedded in the controller of an injection moulding *** results show that the intelligent software can be effectively used in practical production,and it greatly reduces the dependence on the experience of the operators.

关键词： Injection moulding machine (IMM) Process parameters Case based reasoning (CBR) Empirical model (EM) fuzzy logic (FL)

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Zero-energy modes in serially coupled double quantum dots

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Chinese Physics B 2020年第6期29卷 441-445页

作者： fu-Li Sun Zhen-hua Li jian-hua Wei Department of Physics&Beijing Key Laboratory of Optoelectronic functional Materials and Micro-nano Devices Renmin University of ChinaBeijing 100872China School of Physical Science and Technology&Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education Lanzhou UniversityLanzhou 730000China

We investigate symmetrically coupled double quantum dots via the hierarchical equations of motion method and propose a novel zero-energy mode(ZEM) at a temperature above the spin singlet–triplet transition temperature. Owing to the resonance of electron quasi-particle and hole quasi-particle, ZEM has a peak at ω = 0 in the spectral density *** further examine the effect of the magnetic field on the ZEM, where an entanglement of spin and charge has been determined;therefore, the magnetic field can split the ZEM in the spectra.

关键词： zero-energy mode quantum dot temperature

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Travelling Wave Solutions in Delayed Reaction Diffusion Systems with Partial Monotonicity

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Acta Mathematicae Applicatae Sinica 2006年第2期22卷 243-256页

作者： jian-hua huang Xing-fu Zou Department of Mathematics National University of Defense Technology Changsha 410073 China Department of Mathematics and Statistics Memorial University of Newfoundland St. John's NF A1C5S7 Canada

This paper deals with the existence of travelling wave fronts of delayed reaction diffusion systems with partial quasi-monotonicity. We propose a concept of ＂desirable pair of upper-lower solutions＂, through which a subset can be constructed. We then apply the Schauder＇s fixed point theorem to some appropriate operator in this subset to obtain the existence of the travelling wave fronts.

关键词： Travelling wave fronts upper-lower solution partial monotonicity Schauder's fixed point theorem

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Chattering-free sliding mode control with unidirectional auxiliary surfaces for miniature helicopters

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International Journal of Intelligent Computing and Cybernetics 2012年第3期5卷 421-438页

作者： jian fu Wen-hua Chen Qing-xian Wu Department of Automation Nanjing University of Aeronautics and AstronauticsNanjingChina Department of Aeronautical and Automotive Engineering Loughborough UniversityLoughboroughUK

Purpose-This article proposes a chattering-free sliding mode control scheme with unidirectional auxiliary surfaces(UAS-SMC)for small miniature autonomous helicopters(Trex 250).Design/methodology/approach-The proposed UAS-SMC scheme consists of a nested sequence of rotor dynamics,angular rate,Euler angle,velocity and position ***-It is demonstrated that the UAS-SMC strategy can eliminate the chattering phenomenon exhibiting in the convenient SMC method and achieve a better approaching ***/value-The proposed control strategy is implemented on the helicopter and flight tests clearly demonstrate that a much better performance could be achieved,compared with convenient SMC schemes.

关键词： Unmanned aircraft Approaching speed Flight control Sliding mode control Helicopters Chattering

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Comparison of phenolic profiles and antioxidant activities in skins and pulps of eleven grape cultivars(Vitis vinifera L.)

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Journal of Integrative Agriculture 2019年第5期18卷 1148-1158页

作者： LI fu-xiang LI fu-hua YANG Ya-xuan YIN Ran MING jian College of Food Science Southwest University Research Center of Food Storage & Logistics Southwest University Ernest Mario School of Pharmacy Rutgers University

Eleven grape cultivars were analysed to explore the variety differences of fresh grape phenolic profiles. The results showed that free phenolics were predominant in grape skins and pulps, and showed the higher antioxidant activities than bound. In 11 cultivars, Muscat Kyoho extracts had the highest total phenolic content in skins(10.525 mg GAE g^(–1) FW) and pulps(1.134 mg GAE g^(–1) FW), and exhibited the highest DPPH radical scavening capacity(EC_(50)=11.7 μg mL^(–1)) and oxygen radical absorbance capacity(ORAC) value(190.57 μmol TE g^(–1) FW) of free phenolic in skin. In addition, the most abundant phenolics in grape skins were found to be flavonoids such as kaempferol in Kyoho skin(541.2 μg g^(–1) FW), rutin, catechin and epicatechin in Muscat Kyoho skin(262.3, 86.3 and 70.0 μg g^(–1) FW, respectively). furthermore, the principal component analysis showed a strong difference of phenolic profiles with the cultivars, existing forms and distributions. Pearson correlation coefficient analysis showed a significant linear correlation between total phenolic content and antioxidant activity(P<0.05). Therefore, both skins and pulps were rich sources of bioactive phenolic compounds, and Muscat Kyoho was the ideal source among all samples.

关键词： grape phenolics varietal diversity antioxidant activity principal component analysis

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Synthesis, Crystal Structure and Antibacterial Activities of 3-[(2-Hydroxy-4-diethylamino-phenyl)methylenehydrazinocarbonyl]-4-hydroxy-6-methyl-2(1H)-pyridinones

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Chinese Journal of Structural Chemistry 2006年第5期25卷 626-630页

作者： LI Fang PAN fu-You YANG jian-Guo GE Chang-hua Department of Chemistry Taizhou University Zhejiang 317000 China Office of Assets Administration Taizhou University Zhejiang 317000 China

The title compound C18H22N4O4 was synthesized by the reaction of 3-hydrazine-4-hydroxy-6-methyl-2（1H）-pyridinones with 2-hydroxy-4-diethylaminobenzaldehyde in ethanol and characteri- zed by IR, tH NMR and elemental analysis. The single-crystal structure has been determined by X-ray diffraction analysis. The crystal belongs to the triclinic system, space group P1^- with a = 10.1930（14）, b = 12.5200（17）, c = 15.1863（19） A, α= 96.292（3）, β= 96.450（3）, γ= 102.443（3）°, V= 1862.6（4） A^3, Z= 4, Mr = 358.40, μ = 0.092 mm^-1, D c= 1.278 g/cm^3, F（000） = 760 and R = 0.0803. The crystal structure involves intermolcular N-H…O as well as intramolcular O-H…N, O-H…O and N-H…O hydrogen bonds. The title compound shows no antibacterial activity.

关键词： 2(1H)-pyridinones X-ray diffraction crystal structure synthesis antibacterial activities

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平板运动试验、运动及潘生丁负荷心肌断层显像对冠心病诊断的评价

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实用医技杂志 2004年第8B期11卷 1532-1534页

作者：李建华李殿富冯建林付昌文傅裕江苏省人民医院江苏南京210029

目的 :评价亚极量平板运动试验 (TET)、运动负荷心肌断层 (SPECT)显像及潘生丁负荷心肌SPECT显像对冠心病 (CAD)的诊断价值。方法 :以冠状动脉造影 (CAG)为标准 ,83例做过CAG的患者被分为CAD组 (n =37)和非CAD组 (n =4 6 )。所有患者均... 详细信息

目的 :评价亚极量平板运动试验 (TET)、运动负荷心肌断层 (SPECT)显像及潘生丁负荷心肌SPECT显像对冠心病 (CAD)的诊断价值。方法 :以冠状动脉造影 (CAG)为标准 ,83例做过CAG的患者被分为CAD组 (n =37)和非CAD组 (n =4 6 )。所有患者均行TET ,5 6例患者行运动负荷心肌SPECT显像 ,2 7例患者行潘生丁负荷心肌SPECT显像。对比分析TET、运动及潘生丁负荷心肌SPECT显像诊断CAD的灵敏度、特异性、准确性、阳性预测值、阴性预测值。结果 :TET、运动及潘生丁负荷心肌SPECT显像诊断CAD的灵敏度分别为 5 1.4 %、95 .5 %、93.3% ;特异性分别为 76 .1%、88.2 %、91.7% ;准确性分别为 6 5 .1%、91.1%、92 .6 % ;阳性预测值分别为 6 3.3%、84 .0 %、93.3% ;阴性预测值分别为 6 6 .0 %、96 .8%、71.7%。结论 :运动负荷心肌SPECT显像与潘生丁负荷心肌SPECT显像对CAD的诊断价值相近 ,且均优于TET。

关键词：平板运动试验运动潘生丁负荷心肌断层显像冠心病诊断评价

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