Low Temperature Soldering 6061 Aluminum Alloys by Using the Synthesized Sn9Zn Nano-Amorphous Particles

Hao Hong,Ding Min 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.8

To meet the growing demand of technologies of high performance electronics, nano-solders have been widely developed. In the present study, Sn-Zn nano-amorphous particles with core–shell structure were synthesized by a chemical reductionmethod with NaBH4 as reduction agent and Polyvinylpyrrolidone (PVP) as a stabilizer. The size distribution and thermalbehaviour of the as-synthesized nano-particles were controlled by the amount of PVP, whose concentration ranged from 3to 30 wt%. And the change was comparatively confirmed by TEM, DSC and XRD analysis. The results revealed that PVPconcentrations can not only regulate and control the size distribution of the nano-particles and the melting point, whichcould also change the ratio of amorphous shell to crystalline core in nanostructures. In addition, sintering behavior of thisnano-solder soldering 6061 aluminum alloys and its corresponding mechanical properties were evaluated based on SEM,XRD and the shear tests. The results turned out the best bonding quality was obtained under the condition of the content ofPVP is 10 wt%. The obtained shear strength was as high as 17.6 MPa, and the elemental composition of the thinner IMClayer was Al2Zn3,which revealed a good solderability property. The above analysis provided a new insight into the effects ofPVP content on the interfacial reaction mechanism. This bonding technology was suitable for the electronic devices bondedat low temperature.

Soldering 6061 Al by Sn9Zn Coating With/Without Two Step Ultrasonic Effect

Hao Hong,Ding Min 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.8

The work described the effect of soldering 6061 Al by soldering coating with/without two step ultrasonic process, basedon Sn9Zn alloy prepared by high frequency melting and rapid solidification. The microstructure, interfacial morphology,shear strength and mechanical morphology of 6061 aluminum alloy soldered joints were compared and analyzed. Theresults showed that the ultrasonic soldering with coating by two step ultrasonic process technology could greatly improvethe morphology of the joints and refine the grain size. The solder layer with larger scallop shape was transformed into adense fine structure. After two step ultrasonic effect, the width of the joint was about 28% higher than that under the firstultrasonic process. The Zn-rich phase length decreased from an average of 90 μm to an average of 25 μm, about 27% of theoriginal length. The refinement of solder seam was related to the additional dissolved Al and IMC particles. The refinementmechanism was mainly sono-crystallization + sono-fragmentation with two step ultrasonic effect, which was different fromthe refinement mechanisms of the first ultrasonic effect with sono-crystallization. At the same time, the shear strength of6061 aluminum alloy joints bonded at low temperature could reach 230 MPa by two step ultrasonic effect. Compared withthe ultrasonic soldering with coating, the hardness and maximum strength were improved by 14.5% and 28%, respectively.

A New Modulation to Eliminate the Impact of Overlap Time for Three-Phase Current Source Converters

Ding Hao,Guo Xiaoqiang,He Meiling,Shi Changli,Jia Dongqiang,Chen Chao,Guerrero Josep M. 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.5

Three-phase current source converter tends to be attractive in future industrial applications. In order to ensure the continuous current for the dc-link inductor of the current source converter (CSC), an overlap time is mandatory for each switch, so as to avoid the over-voltage spike caused by the dc-link inductor current interruption. However, the overlap time results in the undesirable harmonics and current distortion, which fails to comply with the relevant IEEE Standard in terms of power quality. Especially, the negative infl uence caused by overlap time eff ect is much more serious with the increasing of the switching frequency applied to CSC. In order to solve the problem, the impact of the overlap time on the CSC is investigated, and the error resulted from the overlap time is clearly demonstrated. Based on the pulse equivalent principle and the Fourier analysis, the quantitative relationship between the current harmonic and the overlap time is obtained. And then, a new approach to eliminate the impact of overlap time on the CSC is proposed. Finally, the simulation and experimental results are carried out to verify the eff ectiveness of the proposed solution.

MiR-601 inhibited small cell lung cancer progression by modulating SIRT1

Ding Hao,Gong Chenhu,Zhang Zhihong,Xu Hui,Ma Chunping 대한독성 유전단백체 학회 2023 Molecular & cellular toxicology Vol.19 No.3

Background Dysfunction of microRNAs (miRNAs) contribute to small cell lung cancer (SCLC) progression. Accumulating evidence indicated miR-601, acted as a tumor suppressor gene, has shown an altered expression pattern in multiple cancers. However, little was known about in terms of the function of miR-601 during SCLC progression. Objective Our project intended to illustrate the functions of miR-601 during the development and metastasis of SCLC. Results We found a decreased expression of miR-601 in SCLC tumor tissues and cell lines. Moreover, functional studies suggested that miR-601 overexpression resulted in a reduced cell growth and induced apoptosis of SCLC cells. Notably, sirtuin 1 (SIRT1) was identifi ed as a putative target of miR-601. MiR-601 suppressed SIRT1 expression via interacting with the 3′-untranslated region (UTR) of SIRT1 in SCLC cells. Also, SIRT1 expression was negatively associated with that of miR-601 in SCLC tissues. The restoration of SIRT1 alleviated the inhibitory eff ect of miR-601 on SCLC progression. Conclusion Our data documented the tumor-suppressive function of miR-601 in SCLC via targeting SIRT1, suggesting miR-601 as a new potential therapeutic approach for SCLC treatment.

A higher-order beam model for the snap-buckling analysis of FG pipes conveying fluid

Hao-Xuan Ding,Gui-Lin She 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.80 No.1

The snap buckling of the FG curved pipes conveying fluid has not been reported due to the existing research on the snap-buckling problem. Therefore, the purpose of this paper is to explore this issue. First, we adopt a new high-order shear theory model and consider the thermal and geometric nonlinearity effects, and assume that the density and modulus of elasticity of the liquid are independent of temperature. Based on the generalized variational principle, the governing equation of the FG curved pipes conveying fluid is derived. Then, we assume that the FG curved pipes conveying fluid has simply supported boundary or fixed supported boundary conditions, and use the two step perturbation method to obtain the expression of the relationship between load and deflection. Then, we investigate the influence of boundary conditions, shear deformation, temperature variation, functional gradient index parameters, liquid flow velocity and geometry size on the snap buckling problems of the FG curved pipes conveying fluid. The results show that these factors have significant influence on the fluidstructure interaction problems.

Synthesis of Palladium Nanocubes/Nanorods and Their Catalytic Activity for Heck Reaction of Iodobenzene

Ding, Hao,Dong, Jiling Korean Society of Microscopy 2016 Applied microscopy Vol.46 No.2

Palladium has been used as a catalyst not only in Suzuki and Heck cross coupling reaction in organic chemistry, but also in automobile industry for the reduction of vehicle exhausts. The catalytic activity of Pd nanoparticles depends strongly on their size and exposed crystalline facets. In this study, the single crystalline palladium nanocubes/nanorods were prepared in the presence of polyvinyl pyrrolidone (PVP) and potassium bromide (KBr) using the polyol method. Selected area diffraction pattern and high-resolution transmission electron microscopy (TEM) were performed by TEM. The result shows that the ratio of KBr/PVP is the key factor to determine whether the product is cubes or rods. The as-prepared Pd nanocubes were highly uniform in both size and shape. The ordered packing structures including monolayer and multilayer can be fabricated via the rate-controlled evaporation of solution solvent. The catalytic activity of these Pd nanocubes towards heck reaction of iodobenzene with acrylate or acrylic acid was found to be higher than that of Pd nanorods. We suspect it is caused by the difference of energy state while Pd nanocubes is {100} plane and nanorods is {111} plane.

Transcriptome analysis of flower colour reveals the correlation between SNP and differential expression genes in Phalaenopsis

Ding Yu,Wang Ma-Yin,Yang Ding-Hai,Hao Dai-Cheng,Li Wei-Shi,Ling Peng,Xie Shang-Qian 한국유전학회 2023 Genes & Genomics Vol.45 No.12

Background Phalaenopsis is an important ornamental plant that has great economic value in the world flower market as one of the most popular flower resources. Objective To investigate the flower colour formation of Phalaenopsis at the transcription level, the genes involved in flower color formation were identified from RNA-seq in this study. Methods In this study, white and purple petals of Phalaenopsis were collected and analyzed to obtained (1) differential expression genes (DEGs) between white and purple flower color and (2) the association between single nucleotide polymorphisms (SNP) mutations and DEGs at the transcriptome level. Results The results indicated that a total of 1,175 DEGs were identified, and 718 and 457 of them were up- and down-regulated genes, respectively. Gene Ontology and pathway enrichment showed that the biosynthesis of the secondary metabolites pathway was key to color formation, and the expression of 12 crucial genes (C4H, CCoAOMT, F3’H, UA3’5’GT, PAL, 4CL, CCR, CAD, CALDH, bglx, SGTase, and E1.11.17) that are involved in the regulation of flower color in Phalaenopsis. Conclusion This study reported the association between the SNP mutations and DEGs for color formation at RNA level, and provides a new insight to further investigate the gene expression and its relationship with genetic variants from RNA-seq data in other species.

Effect of air gap interval on polyvinylidene fluoride hollow fiber membrane spinningfor CO2 and CH4 gas separation

Sie Hao Ding,Pei Ching Oh,Asif Jamil 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.9

Improper control of air gap interval during hollow fiber membranes (HFMs) spinning may lead to structuraldefects such as inner lumen deformations and macrovoids. In the current work, PVDF HFMs were prepared bymanipulating air gap intervals at 5, 10, 15, 20, and 25 cm, using dry-wet spinning mechanism. The changes in its properties,including contact angle, mechanical strength, and most importantly the morphological structure that is usuallycrucial for gas separation performance have been determined. The morphology was evaluated using SEM, and theinner lumen defects of HFMs were reduced with the increment of air gap interval during the spinning process. Subsequently,the CO2 gas permeance was observed to increase from 5 to 15 cm air gap distance and almost constant at20 cm air gap interval, then increase tremendously beyond this point. Furthermore, CO2/CH4 ideal selectivity wasobserved to be improved and reached the highest end at PVDF-AG15 and dropped beyond this point. Therefore, varyingair gap distance is considered as a practical approach for better gas separation. However, macrovoids will form ifthe air gap length is overlong. Thus, optimum air gap length during PVDF HFMs spinning is vital for morphology andgas separation performance.

Study on the Seismic Optimization Scheme of Steel Bundled-Tube Structure with Vertical Setback

Yong Hao,Feng Chen,Yun-hui Han,Xue-qian Hao,Chun-hui Du,Qiu-yu Ding 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.2

In order to improve the seismic performance of vertical setback steel bundled-tube structure and meet the dynamic multi-objective requirements of seismic performance-based design, the optimization effects under rare earthquakes on the zone of fortification intensity 7 and 8 in China are researched by improving members stiffness and adding dampers in the weak parts of structure, based on dynamic elastic-plastic analysis. The results show that: 1) Under rare earthquakes on the zone of fortification intensity 7, increasing the stiffness of weak skirt beam can improve the seismic performance of spiral and symmetrical setback structure; 2) For the spiral setback structure, under rare earthquakes on the zone of fortification intensity 7, the damper can only be arranged at the junction of the first layer of the setback frame unit and the frame unit without setback. However, under rare earthquakes on the zone of fortification intensity 8, it is not advisable to install dampers at the weak areas; 3) After incorporating dampers at the weak areas of symmetrical setback structure, the optimized members experienced a reduction in stress levels, significantly decreased the inter-layer displacement angles with a maximum reduction of 43%, and the optimization effect is significant.

Effects of inulin diet supplementation on production performance, gut traits, and incidence of ascites in Haidong chicks under hypoxic conditions

Ding Baoan,Chen Lingyun,Lin Hao,Wang Xiezhong,Zhang Licheng,Ni Xiaoming,Pirone Andrea,Madigosky Stephen R.,Fronte Baldassare 아세아·태평양축산학회 2021 Animal Bioscience Vol.34 No.3

Objective: Effects of inulin supplementation in diet of Haidong chicks under hypoxic conditions on production performance, intestinal morphologic change, microflora contents and the incidence of ascites were studied. Methods: Commercial male chicks (360) were randomly divided into 6 groups and were fed diets supplemented with 0, 0.05, 0.075, 0.1, 0.125, and 0.15 g/kg of inulin, respectively. Results: The body weight gain and feed intake were improved in chicks fed the diets supplemented with 0.1 and 0.125 g/kg of inulin, from d 1 to d 42 (p<0.05); moreover, blood parameters were positively affected when inulin was included in the diets and the thickness of the intestinal wall and muscle tissue in duodenum, jejunum, and ileum tended to increase (p<0.05), and the villi height and crypt depth in duodenum, jejunum, and ileum (p<0.05). Regarding the number of goblet cells in duodenum, jejunum and ileum tended to increase when chicks were fed the diets supplemented with 0.075, 0.1, 0.125, and 0.15 g/kg (p<0.05) of inulin. When chicks were fed diets supplemented with 0.75 or 0.1 g/kg of inulin, a significant reduction of Escherichia coli counts in the cecum was observed; for a contrary, a significant increment of Bifidobacterium and Lactobacillus was observed in cecum and ileum. Finally, supplementing the feed with inulin determined an overall reduction of ascites incidences in comparison to the control group. Conclusion: Thus, the results observed in the present study clearly suggest that the diet supplementation with a quantity of inulin ranging between 0.1 and 0.125 g/kg, can improve growth performances, intestinal morphology, internal microbial balance and ascites incidence, in broiler chicks raised at high altitude area. Even though these findings may be of interest for the poultry industry, they may particularly be relevant in those areas characterized by high altitude such as Northwest China regions. Objective: Effects of inulin supplementation in diet of Haidong chicks under hypoxic conditions on production performance, intestinal morphologic change, microflora contents and the incidence of ascites were studied.Methods: Commercial male chicks (360) were randomly divided into 6 groups and were fed diets supplemented with 0, 0.05, 0.075, 0.1, 0.125, and 0.15 g/kg of inulin, respectively.Results: The body weight gain and feed intake were improved in chicks fed the diets supplemented with 0.1 and 0.125 g/kg of inulin, from d 1 to d 42 (p<0.05); moreover, blood parameters were positively affected when inulin was included in the diets and the thickness of the intestinal wall and muscle tissue in duodenum, jejunum, and ileum tended to increase (p<0.05), and the villi height and crypt depth in duodenum, jejunum, and ileum (p<0.05). Regarding the number of goblet cells in duodenum, jejunum and ileum tended to increase when chicks were fed the diets supplemented with 0.075, 0.1, 0.125, and 0.15 g/kg (p<0.05) of inulin. When chicks were fed diets supplemented with 0.75 or 0.1 g/kg of inulin, a significant reduction of <i>Escherichia coli</i> counts in the cecum was observed; for a contrary, a significant increment of <i>Bifidobacterium</i> and <i>Lactobacillus</i> was observed in cecum and ileum. Finally, supplementing the feed with inulin determined an overall reduction of ascites incidences in comparison to the control group.Conclusion: Thus, the results observed in the present study clearly suggest that the diet supplementation with a quantity of inulin ranging between 0.1 and 0.125 g/kg, can improve growth performances, intestinal morphology, internal microbial balance and ascites incidence, in broiler chicks raised at high altitude area. Even though these findings may be of interest for the poultry industry, they may particularly be relevant in those areas characterized by high altitude such as Northwest China regions.