Fabrication of Al–Ti–B Grain Refiner Using Machining Ti Chips, Reaction Mechanisms and Grain Refinement Performance in Pure Al

Maoliang Hu,Fei Wang,Bo Jiang,Huasheng Wang,Yile Liu,Zesheng Ji 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.6

Al–5Ti–1B grain refiner was successfully prepared with the reaction of Ti chips produced during machining and KBF4inpure aluminum melt. In order to illustrate the reaction mechanism of Ti chips, the effect of different feeding ways and reactiontimes of Ti chips on microstructure and refining performance of Al–5Ti–1B was systematically investigated by opticalmicroscope, scanning electron microscopy and X-ray diffractometer. The results show that, in three feeding ways, includingadding Ti chips firstly, adding KBF4firstly and adding both Ti chips and KBF4in the form of prefabricated blocks, the bestrefining performance of Al–5Ti–1B is the feeding way of using the prefabricated block. TiB2and TiAl3as effective heterogeneousnuclei are formed simultaneously around the Ti chips. The average grain size of pure aluminum is refined to about206.80 μm. The reaction time mainly affects the dissolution process of Ti chips and the average size of TiAl3. With the reactiontime from 60 min to 90 min and then to 120 min, the average size of TiAl3increases from 10.74 μm to 14.30 μm and thento 15.39 μm. During the dissolution process, Ti chips undergo a transition from a thermal isolation layer to a supersaturatedzone of Ti atoms. Based on the analysis of the dissolution process of Ti chips, the dissolution model is proposed. Al–5Ti–1B has the best refining performance at 90 min of the reaction time, which can refine pure aluminum to about 223.65 μm.

Influence of Microstructure and Mechanical Properties on Formability in High Strain Rate Rolled AZ31 Magnesium Alloy Sheets

Fubao Liu,Xiao Liu,Biwu Zhu,Hui Yang,Gang Xiao,Mingyue Hu 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.6

High strain-rate rolling (≥ 10 s−1) has been successfully employed to produce AZ31 magnesium alloy sheets to a high reductionof 82% with a fine grain structure in a single pass. The rolled sheets inevitably undertake various forming processessuch as press and deep forming in the fabrication stage. To investigate the formability, the Erichsen tests were carried out onhigh strain rate rolled AZ31 magnesium alloy sheets at room temperature. The relationship among mechanical properties,microstructure and formability were investigated. The crack behavior during Erichsen tests was also studied. It was foundthat the formability was related to the lowest in-plane tensile strengthen and dislocation density of initial microstructure. The competitive relationship between micro-crack and twinning/shear bands would also influence the formability of highstrain rate rolled magnesium alloy sheets. Deformed shear band with substaintial twins prohibits the crack extension andenhances strengthen of materials in front of crack tip.

In Vitro Evaluation and Monitoring of the Expression Level and Localization of Aldose Reductase Using Functionalized Quantum Dots and EGFP

Xiaomin Liu,Chengbin Yang,Jing Liu,Jianwei Liu,Rui Hu,Hongwei Lian,Guimiao Lin,Liwei Liu,Ken-Tye Yong,Ling Ye 한국생물공학회 2015 Biotechnology and Bioprocess Engineering Vol.20 No.4

The optimization of aldose reductase (AR) expression levels and tracking of the AR expression sites within the cell is an essential step in developing a platform for the effective production of aldose reductase inhibitors (ARIs). In this study, we have demonstrated the use of both immunocytochemistry and quantum dots-based immunofluorescence techniques for observing and detecting the expression level and localization of AR in the cytoplasm and cell membrane of a eukaryotic cell model with high levels of AR protein expression. Our results show that high expression levels of human AR can be achieved using the eukaryotic cell model that we have developed. The overexpressed AR can be used for translational studies of hAR and the screening of ARIs. More importantly, the use of the established quantum dots-based immunofluorescence technique in the intracellular labeling of AR allows the determination of the expression and distribution of the AR gene. Overall, the use of the interdisciplinary approach of both genetic engineering and quantum dot-based immunofluorescence allows not only the effective production of a desired protein, but also the determination of the cellular localization of such an expressed protein.

Identification of QTLs associated with the anaerobic germination potential using a set of Oryza nivara introgression lines

Licheng Liu,Xiaoxiang Li,Sanxiong Liu,Jun Min,Wenqiang Liu,Xiaowu Pan,Baohua Fang,Min Hu,Zhongqi Liu,Yongchao Li,Haiqing Zhang 한국유전학회 2021 Genes & Genomics Vol.43 No.4

Background Rice (Oryza sativa L.) is an important crop and a staple food for half of the population around the world. The recent water and labor shortages are encouraging farmers to shift from traditional transplanting to direct-seeding. However, poor germination and slow elongation of the coleoptile constrains large-scale application of direct-seeding. Objective Thisstudy was aimed to investigate the genetic basis of the anaerobic germination(AG) potential using a set of Oryza nivara (O. nivara) introgressionlines (ILs). Methods Inthis study, a total of 131 ILs were developed by introducing O. nivara chromosomesegments into the elite indica rice variety 93-11 through advanced backcrossingand repeated selfng. A high-density genetic map has been previouslyconstructed with 1,070 bin-markers. The seeds of ILs were germinated and usedto measure coleoptile length under normal and anaerobic conditions. QTLsassociated with AG potential were determined in rice. Results Basedon the high-density genetic map of the IL population, two QTLs, qAGP1 and qAGP3 associated with AG tolerance were characterized and locatedon chromosomes 1 and 3, respectively. Each QTL explained 15% of the phenotypic variance.Specifcally, the O. nivara-derived chromosomesegments of the two QTLs were positively tolerance to anaerobic condition byincreasing coleoptile length. In a further analysis of public transcriptomedata, a total of 26 and 36 genes within qAGP1 and qAGP3 were transcriptionallyinduced by anaerobic stress, respectively. Conclusions Utilizationof O. nivara-derived alleles at qAGP1 and qAGP3 can potentially enhance tolerance to anaerobic stress at thegermination stage in rice, thereby accelerating breeding of rice varieties tobe more adaptative for direct-seeding.

Research on the selective multi-stage two point incremental forming based on the forming angle

Hu Zhu,Luteng Liu,Yibo Liu,Jaeguan Kang 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.8

For sheet metal parts with the vertical-wall partially and irregularly distributed on the sides (VWPIS) that contains both the difficult-form-surface (i.e., vertical-wall) with large forming angle and easy-to-form surface (i.e., gently tilted surface) with small forming angle, a selective multi-stage two point incremental forming (SMTPIF) on the basis of the forming angle was proposed. This SMTPIF method performs multi-stage forming only for the difficult-formsurface and gives different forming strategies and forming parameters to the different surface regions according to the forming angle. The algorithms for surface zoning, generation of the small forming angle surface for vertical-wall, generation of one-stage forming model by combining the easy-form-surface and small forming angle surface were presented. Meanwhile, the algorithm for the generation of the toolpath that is suitable to the SMTPIF was also given. The effectiveness of the proposed algorithm and the SMTPIF was verified by using the case studies, the finite element analysis, and the forming experiments. The results indicate that the SMTPIF can fabricate the VWPIS with short forming time and no sinking phenomenon.

Applicability research of round tube CHF mechanistic model in rod bundle channel

Liu, Wei,Peng, Shinian,Shan, Jianqiang,Jiang, Guangming,Liu, Yu,Deng, Jian,Hu, Ying Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.2

In view of the complex geometric structure of the rod bundle channel and the limitation of the current CHF visualization experiment technology, it is very difficult to obtain the rod bundle CHF mechanism directly through the phenomenon of the rod bundle CHF visualization experiment. In order to obtain the applicable CHF mechanism assumption for rod bundle channel, firstly, five most representative DNB type round tube CHF mechanistic models are obtained with evaluation and screening. Then these original round tube CHF mechanistic models based on inlet conditions are converted to local conditions and coupled with subchannel analysis code ATHAS. Based on 5 × 5 full-length rod bundle CHF experimental data independently developed by Nuclear Power Institute of China (NPIC), the applicability research of each model for CHF prediction performance in rod bundle channel is carried out, and the commonness and difference of each model are comparatively studied. The CHF mechanism assumption of superheated liquid layer depletion that is most likely to be applicable for the rod bundle channel is selected and two directions that need to be improved are given. This study provides a reference for the development of CHF mechanistic model in rod bundle channel.

Naphthalene-based poly(arylene ether ketone) anion exchange membranes

Liu, Z.,Li, X.,Shen, K.,Feng, P.,Zhang, Y.,Xu, X.,Hu, W.,Jiang, Z.,Liu, B.,Guiver, M. Royal Society of Chemistry 2013 Journal of materials chemistry. A, Materials for e Vol.1 No.21

STABILITY OF THE MILSTEIN METHOD FOR STOCHASTIC DIFFERENTIAL EQUATIONS WITH JUMPS

Liu Hu,Siqing Gan 한국전산응용수학회 2011 Journal of applied mathematics & informatics Vol.29 No.5

In this paper the Milstein method is proposed to approximate the solution of a linear stochastic differential equation with Poisson-driven jumps. The strong Milstein method and the weak Milstein method are shown to capture the mean square stability of the system. Furthermore using some technique, our result shows that these two kinds of Milstein methods can well reproduce the stochastically asymptotical stability of the system for all suffciently small time-steps. Some numerical experiments are given to demonstrate the conclusions.

Metabolizable energy requirement for maintenance estimated by regression analysis of body weight gain or metabolizable energy intake in growing pigs

Hu Liu,Yifan Chen,Zhongchao Li,Yakui Li,Changhua Lai,Xiang Shu Piao,Jaap van Milgen,Fenglai Wang 아세아·태평양축산학회 2019 Animal Bioscience Vol.32 No.9

Objective: Feed energy required for pigs is first prioritized to meet maintenance costs. Additional energy intake in excess of the energy requirement for maintenance is retained as protein and fat in the body, leading to weight gain. The objective of this study was to estimate the metabolizable energy requirements for maintenance (MEm) by regressing body weight (BW) gain against metabolizable energy intake (MEI) in growing pigs. Methods: Thirty-six growing pigs (26.3±1.7 kg) were allotted to 1 of 6 treatments with 6 replicates per treatment in a randomized complete block design. Treatments were 6 feeding levels which were calculated as 50%, 60%, 70%, 80%, 90%, or 100% of the estimated ad libitum MEI (2,400 kJ/kg BW0.60 d). All pigs were individually housed in metabolism crates for 30 d and weighed every 5 d. Moreover, each pig from each treatment was placed in the open-circuit respiration chambers to measure heat production (HP) and energy retained as protein (REp) and fat (REf) every 5 d. Serum biochemical parameters of pigs were analyzed at the end of the experiment. Results: The average daily gain (ADG) and HP as well as the REp and REf linearly increased with increasing feed intake (p<0.010). β-hydroxybutyrate concentration of serum tended to increase with increasing feed intake (p = 0.080). The regression equations of MEI on ADG were MEI, kJ/kg BW0.60 d = 1.88×ADG, g/d+782 (R2 = 0.86) and MEm was estimated at 782 kJ/kg BW0.60 d. Protein retention of growing pigs would be positive while REf would be negative at this feeding level via regression equations of REp and REf on MEI. Conclusion: The MEm was estimated at 782 kJ/kg BW0.60 d in current experiment. Furthermore, growing pigs will deposit protein and oxidize fat if provided feed at the estimated maintenance level.

Synthesis and Evaluation O-Benzyl Oxime-ether Derivatives Containing β-Methoxyacrylate Moiety for Insecticidal and Fungicidal Activities

Hu, Zhi-Bin,Luo, He-An,Wang, Xiao-Guang,Huang, Ming-Zhi,Huang, Lu,Pang, Huai-Lin,Mao, Chun-Hui,Pei, Hui,Huang, Chao-Qun,Sun, Jiong,Liu, Ping-Le,Liu, Ai-Ping Korean Chemical Society 2014 Bulletin of the Korean Chemical Society Vol.35 No.4

In attempt to lead compounds exhibiting both insecticidal and fungicidal activities, a series of O-benzyl oximeether derivatives were designed and synthesized by introducing ${\beta}$-methoxyacrylate pharmacophore into a scaffold. The insecticidal activity against Aphis fabae and the fungicidal activity against Erysiphe graminis were screened. The title compounds exhibited remarkable insecticidal and fungicidal activities. The most potent compound 6d was identified. Its insecticidal $LC_{50}$ against A. fabae is 6.4 mg/L, which is lower than that of chlorfenapyr (19.4 mg/L) and even close to the level of imidacloprid (4.8 mg/L). Its fungicidal $EC_{90}$ in preventive and curative treatment against E. graminis are 2.2 and 4.8 mg/L, respectively, which are lower than azoxystrobin (7.0 and 5.9 mg/L). These results indicate that compound 6d can be considered as a lead for further developing new O-benzyl oxime-ether typed candidates with both fungicidal and insecticidal activities.