The strength analysis and probabilistic design of a bogie frame with incomplete probabilistic information

Hao Lu,Changyi Wang,Haibao Guo,Hao Lv,Yimin Zhang 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.3

A bogie frame is a key component of high-speed rail; higher requirements of the safety and stability of the bogie frame are put forward with the continuous improvement of the train speed. In this study, we first performed a strength analysis of a bogie frame according to the JIS E 4207 standard by using finite element method. Then, we did a reliability analysis of the bogie frame. The reliability problems are defined as strength reliability and resonant frequency reliability, which indicate the structural safety and stability of the bogie frame. The reliability estimation is realized by experimental design, artificial neural network and stochastic perturbation theory. Additionally, reliability-based sensitivity indices were derived to measure the parameter importance of random input variables. An illustrative example of the bogie frame with incomplete probabilistic information was used to demonstrate the applications of the proposed method for reliability and reliability-based sensitivity estimation in terms of strength and resonant frequency reliability. The results indicate that vertical loads and the material density have more of an impact on reliability than other variables of the bogie frame.

《篆隸萬象名義》逸字考

?浩(Lv Hao) 한국교통대학교 동아시아연구소 2008 동아문헌연구 Vol.- No.-

關于《篆隸萬象名義》校讀的若干問題

?浩(LV Hao) 한국교통대학교 동아시아연구소 2011 동아문헌연구 Vol.- No.-

Age quadratically affects intestinal calcium and phosphorus transporter gene expression in broiler chickens

Lv, Xianliang,Hao, Junfang,Wu, Lihua,Liu, Mengyuan,He, Lei,Qiao, Yingying,Cui, Yanyan,Wang, Guan,Zhang, Chunmei,Qu, Hongxia,Han, Jincheng Asian Australasian Association of Animal Productio 2022 Animal Bioscience Vol.35 No.12

Objective: This research aimed to evaluate the effects of age on growth, tibia development, and intestinal calcium (Ca) and phosphorus (P) transporter gene expressions in broiler chickens. Methods: A total of 224 male Arbor Acres broilers were fed with nutrient-adequate diets and reared in eight cages (28 broilers per cage). Eight broilers (one broiler per cage) were selected and killed at 5, 10, 15, 20, 25, 30, 35, and 40 days of age, respectively. Results: Body weight continuously increased with age of broiler chickens from 5 to 40 days. The bone weight, ash weight, diameter, and length of the tibia also increased with broiler age. By contrast, the tibia ash, Ca, and P percentages quadratically changed with age (p<0.001), and the highest values of mineral contents were observed at 20, 25, and 25 days of age, respectively. The mRNA abundances of calcium-binding protein 28-kDa (CaBP-D28k), sodium-calcium exchanger 1 (NCX1), and plasma membrane ATPase 1b (PMCA1b) increased from 5 to 25 days and then decreased up to 40 days. Similar results were noted in the mRNA abundances of IIb sodium-phosphate cotransporter (NaPi-IIb), inorganic phosphate transporter 1 (PiT-1), inorganic phosphate transporter 2 (PiT-2), nuclear vitamin D receptor (nVDR), and membrane vitamin D receptor (mVDR). The mRNA abundances of Ca and P transporters and VDRs were the highest at 25 days of age. Conclusion: These data indicate that age quadratically affects intestinal Ca and P transporter gene expression and mineral absorption capacity in broiler chickens.

Hierarchical porous N,S-codoped carbon with trapped Mn species for efficient pH-universal electrochemical oxygen reduction in Zn-air battery

Hao-Yu Wang,Jin-Tao Ren,Chen-Chen Weng,Xian-Wei Lv,Zhong-Yong Yuan 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.100 No.-

Highly efficient and ultrastable nonprecious metal-based electrocatalysts are promising alternatives toplatinum (Pt)-based catalysts in electrocatalyzing oxygen reduction reaction (ORR) process. In thepresent work, nitrogen and sulfur dual-doped hierarchically porous carbon with trapped Mn species(MnNSC-950) was fabricated, which integrates the modulation of the electronic structure for boostedintrinsic activity with the engineering of hierarchical porosity for enriched active sites. The MnNSC-950shows a positive onset potential of 0.95 V and a large limiting current density of 5.4 mA cm 2, which canrival that of the commercial Pt/C catalyst in 0.1 M KOH, together with a robust long-term stability. Moreover, the MnNSC-950 as ORR catalyst in Zn-air battery achieves a high power density of107 mW cm 2 and robust cycling performance over 150 h, exceeding that driven by Pt/C cathode. Theexcellent electrochemical performance is also shown in both neutral and acidic media. This workprovides an enabling route to prepare non-noble metal-based catalysts featuring well-engineeredgeometric and component peculiarities for practical application of energy conversion systems.

Kinetics of Enzymatic Synthesis of L-ascorbyl Acetate by Lipozyme TLIM and Novozym 435

Dong-Hao Zhang,Ya-Qiong Li,Chao Li,Yv-Qin Lv,Yang-L 한국생물공학회 2012 Biotechnology and Bioprocess Engineering Vol.17 No.1

L-ascorbyl acetate was synthesized through lipase-catalyzed esterification using Lipozyme TLIM and Novozym 435. Four solvents, including methanol, ethanol,acetonitrile, and acetone were investigated for the reaction,and acetone and acetonitrile were found to be suitable reaction media. The influences of several parameters such as water activity (aw), substrate molar ratio, enzyme loading,and reaction temperature on esterification of Lascorbic acid were systematically and quantitatively analyzed. Through optimizing the reaction, lipase-catalyzed esterification of L-ascorbic acid gave a maximum conversion of 99%. The results from using Lipozyme TLIM and Novozym 435 as biocatalysts both showed that aw was an important factor for the conversion of L-ascorbic acid. The effect of pH value on lipase-catalyzed L-ascorbic acid esterification in acetone was also investigated. Furthermore,results from a kinetic characterization of Lipozyme TLIM were compared with those for Novozym 435, and suggested that the maximum reaction rate for Lipozyme TLIM was greater than that for Novozym 435, while the enzyme affinity for substrate was greater for Novozym 436.

Effects of Sn and Mn Addition on the Microstructure and Mechanical Properties of As-Extruded Mg–2Al–1Zn Alloys

Fu‑Hao Gao,Bin‑Jiang Lv,Tie‑Wei Xu,Ning Cui,Feng Guo 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.11

The effects of low Sn (1.0 wt%) and Mn (0.5 wt%) content on the microstructures and mechanical properties of as-extrudedMg–2Al–1Zn (AZ21) alloys were systematically investigated. The combined addition of Sn and Mn significantly refinedthe grains of the AZ21 alloy, reducing the average grain size from 25.77 to 2.17 μm. The volume fraction of the dynamicallyrecrystallized (DRXed) grains decreased from 78.49 to 43.81% with Sn (1.0 wt%) and Mn (0.5 wt%) addition. The Al8Mn5,Al11Mn4,and Al9Mn4phases were formed in Mg–2Al–1Zn–1Sn–0.5Mn (AZTM2110) alloy, and the Mg17Al12phase disappeared. The orientation relationship between Al9Mn4and Al11Mn4was (002)Al11Mn4//(̄ 302)Al9Mn4, [ ̄ 100]Al11Mn4//[223]Al9Mn4,and the orientation relationship between Al8Mn5and α-Mg was ( ̄ 252)Al8Mn5//(̄ 12̄ 13)α−Mg. The Al9Mn4and Al11Mn4phasesgrew in the same direction. The intensity of basal fiber texture of AZTM2110 alloy decreased by 21.7%. The ultimatetensile strength, yield strength, and elongation of the AZ21 alloy increased by 29.03%, 65.05%, and 61.02%, respectively. Grain-refinement strengthening was the main mechanism underlying the improvement in AZTM2110 alloy strength. Grainrefinement and the weakened basal fiber texture improved the plasticity of the AZTM2110 alloy.

Nitrogen-doped graphene loaded non-noble Co catalysts for liquid-phase cyclohexane oxidation with molecular oxygen

Fang Hao,Yuan Sun,Yidi Wang,Yang Lv,Pingle Liu,Xiong Wei,Hean Luo 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.8

Selective aerobic oxidation of cyclohexane to cyclohexanone and cyclohexanol (KA oil) with high yield under mild and green conditions is still a significant challenge in the current chemical industry. Herein, nitrogen doped graphene loaded non-noble Co (Co-N-rGO) catalysts, prepared by a facile post-impregnation method, exhibited a high catalytic performance and stability in liquid phase cyclohexane oxidation with molecular oxygen. The experiment and characterization results show that N doping in the catalysts promotes Co metal particle dispersion and induces carbon film coating on Co to prevent leaching and agglomeration. Besides, density functional theory (DFT) calculations show that N doping is beneficial to the O-O bonds breaking in cyclohexyl-hydroperoxides (CHHP), thereby promoting the dissociation of CHHP and enhancing the yield to KA oil. In addition, the catalyst can be easily separated without appreciable loss of catalytic activity after recycling for five times, and show potential industrial application value for the catalytic oxidation of cyclohexane to KA oil in the chemical industry.

Effects of habitat fragmentation on the functional diversity of insects in Thousand Island Lake, China

Tian‐Hao Tu,Ji-Rui WANG,Jian-Qiang GU,Tian-Qi LI,Kun LV,Guo-Xin ZHOU,Zhi-Hong XU 한국곤충학회 2019 Entomological Research Vol.49 No.2

Due to habitat fragmentation, the loss of species diversity has been extensively studied. On the contrary, the effects of habitat fragmentation on functional diversity is still poorly understood. In the Thousand Island Lake, we conducted studies of insect functional diversity on a set of 29 isolated islands. We used 10 functional diversity indices from three aspects (functional richness, functional evenness and functional divergence) to respectively describe functional diversity of insects on sample islands. We found the following results: (i) The functional indices selected could reflect the functional diversity of sample islands and it is further proved that in general, three components of functional diversity were independent of each other; (ii) Sample islands could be divided into two categories, island JSD and the remaining islands; (iii) Functional richness increased with island area and shape index, but had no significant correlation with isolation. Likewise, both functional evenness and functional divergence had no significant correlation with island attributes. The conclusion to emphasize from our research is that: (i) habitat fragmentation reduced the biological functional diversity to some extent, further demonstrating the importance of habitat continuity in biodiversity protection; and (ii) for functional diversity protection of insects in a fragmented landscape, an island which has high approximate shape index values of at least hundred hectare magnitude order has a critical promoting effect.

Approximate Optimal Stabilization Control of Servo Mechanisms based on Reinforcement Learning Scheme

Yongfeng Lv,Xuemei Ren,Shuangyi Hu,Hao Xu 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.10

A reinforcement learning (RL) based adaptive dynamic programming (ADP) is developed to learn the approximate optimal stabilization input of the servo mechanisms, where the unknown system dynamics are approximated with a three-ayer neural network (NN) identifier. First, the servo mechanism model is constructed and a three-layer NN identifier is used to approximate the unknown servo system. The NN weights of both the hidden layer and output layer are synchronously tuned with an adaptive gradient law. An RL-based critic three-layer NN is then used to learn the optimal cost function, where NN weights of the first layer are set as constants, NN weights of the second layer are updated by minimizing the squared Hamilton-Jacobi-Bellman (HJB) error. The optimal stabilization input of the servomechanism is obtained based on the three-layer NN identifier and RL-based critic NN scheme, which can stabilize the motor speed from its initial value to the given value. Moreover, the convergence analysis of the identifier and RL-based critic NN is proved, the stability of the cost function with the proposed optimal input is analyzed. Finally, a servo mechanism model and a complex system are provided to verify the correctness of the proposed methods.