Investigation and Verification of Fatigue Characteristic on the Adhesive Slanted Interface of Specimen with Foaming Aluminum for Sliding Mode

Sun, Hong Peng,Cho, Jae Ung Korean Society for Precision Engineering 2015 International Journal of Precision Engineering and Vol.16 No.11

Foaming aluminum is a super light weight manufactured by adding thickener and foaming agent after dissolving aluminum ingot to be foamed in a sponge configuration. Studying on fatigue of adhesive structures configured with aluminum foam and fracture toughness for adhesive interfaces may be considered very important. In this study, DCB specimens of aluminum foam composite material were designed based on British industrial standard (BS 7991) and ISO international specification (ISO 11343), and Mode II tests were performed. Examination of graphs of loads and displacements according to fatigue cycles for the four types of specimens shows that time capable of withstanding fatigue loads is the longer, the larger the slanted angle of the tapered double cantilever beam model under the same fatigue load conditions. Since similar results to those from actual experiments were observed based on comparisons of actual experimental data with analysis data, the analysis results according to a finite element method employed in this study could be relied upon, and it is considered that structural safety could be found by imulations alone in lieu of experiments requiring much cost and time when such method as this is applied.

Simulation Analysis and Experimental Verification for the Adhesive Strength Properties of Aluminum Foam Specimen for the Slip Mode

Hong Peng Sun,조재웅 한국정밀공학회 2015 International Journal of Precision Engineering and Vol.16 No.12

In this study, the thickness was set as the variable and TDCB specimen was designed in order to investigate the adhesion strength characteristics of the slip mode made from aluminum foam. The dimensions of the models are the length of 200 mm and various thicknesses of 15 mm, 30 mm, 45 mm, and 75 mm. According to analysis results of the model with 15 mm thickness, when the forced displacement became about 5.3 mm, the maximum load appeared to be 188 N and a maximum equivalent stress of about 2.99 MPa occurred, respectively. According to the analysis results of specimens, when the propagation of the forced displacement is about 5.3 mm, a maximum reaction force of about 940 N appears whereas when the propagation of the forced displacement is about 22 mms, the reaction force almost disappears. When the trend of experiments and analysis results are applied to the four models used in this study, the adhesion strength of TDCB adhesive structure made from the aluminum foam of varying thickness can be evaluated. Therefore, it is expected that the structural safety can be anticipated by only an analysis without experiments in the actual adhesive structure.

A Study on the Fracture Characteristics of Tapered Double Cantilever Specimens Bonded with Aluminum Foams of Varying Thicknesses

Sun, Hong Peng,Cho, Jae Ung Korean Society for Precision Engineering 2015 International Journal of Precision Engineering and Vol.16 No.10

In this study, the fracture characteristics on the adhesive interfaces in the structures composed of aluminum foam were investigated by using three kinds of TDCB specimens with the thicknesses of 25 mm, 50 mm and 75 mm and the length of 200 mm. According to the test results for the 25 mm-thick specimens, the maximum reaction force of about 200 N was shown when forced displacement progressed as the amount of about 6 mm to 7 mm. And the reaction force nearly was disappeared after the forced displacement progressed as the amount of about 22 mm. Similar trends were observed in cases of other specimens with thicknesses of 50 mm and 75 mm. As the forced displacement was gradually increased,fractures began to occur with the separation from the bonded interface beginning when the equivalent stress happened at the bonded interface was larger than the adhesive stress of 0.167 MPa at the bonding interface. Such experimental results can be verified by simulation analysis results. Therefore, fracture characteristics of aluminum foam consisting of the porous cores are considered to be identifiable through only simulations instead of experiments without requiring significant cost or time.

Experiment and Analysis Verification of Shearing Fracture Characteristic of Tapered Double Cantilever Beam with Aluminum Foam

Hong Peng Sun,조재웅 한국정밀공학회 2015 International Journal of Precision Engineering and Vol.16 No.7

In this study, mode II(sliding) adhesive strengths of tapered double-cantilever beam (TDCB) specimens of aluminum foams bonded with adhesives were evaluated by finite element analysis. Models were fabricated for testing, and their length and thickness were 200 mm and 25 mm, respectively, while the angles between the adhesive layers and the horizontal direction for models (a), (b), and (c) were 8o, 10o, and 12o, respectively. The joint adhesive method was applied to the models that were made of Al-SAF40, aluminum foam. To generate the crack in shear direction, one end of the loaded block was restrained with a frictionless support while the other end of the loaded block was set to be displaced at the rate of 10 mm/min in the adhesive layer. The analysis and comparison result between the 3 different models revealed that the larger the tilt angle θ of sliding mode was, the larger the maximum load became, while the time to reach the maximum load and the time taken until the load disappeared were shorter as the value increased in the displacement-force reaction curve. This study can be applied to real structures with tapered contact surfaces by analyzing fracture behaviors and characteristics of composite materials such as aluminum foams bonded with adhesives.

발포 알루미늄으로 된 경사진 이중외팔보 시험편의 접착면에서의 전단 실험 및 시뮬레이션 해석

손홍붕 ( Hong Peng Sun ),전성식 ( Seong S. Cheon ),조재웅 ( Jae Ung Cho ) 한국복합재료학회 2014 Composites research Vol.27 No.6

본 연구에서는 발포 알루미늄으로 구성된 접착 구조물에서의 접합면에 대한 파괴 특성을 조사하기 위하여 각도를 변수로 정하고 TDCB 시험편을 설계하였다. 이 시험편들은 길이는 200 mm이고 시험편에 대한 접착면의 경사 각도는 6°, 8°, 10°와 12°인 네 가지로 모델링을 하였다. 이 시험편들의 실험 및 해석을 분석한 결과, 경사면각도가 6°, 8°, 10°와 12°인 경우에 시험편들의 최대 하중은 각각 약 120 N, 137 N, 154 N과 171 N으로 발생하였다. 해석의 결과 값이 실험치에 가까워져 많은 차이를 보이지 않는 것을 확인할 수 있다. 따라서 이와 같은 연구 방법을응용하여 실험 대신 시뮬레이션을 통하여 접착제로 접착된 알루미늄 폼으로 된 재료의 전단 거동에 관한 물성치를 효율적으로 파악할 수 있다고 사료된다. In this study, tapered double cantilever beam specimens are designed with the variable of angle toinvestigate the fracture property at the bonded surface of adjoint structure. These specimens are made with four kindsof models as the length of 200 mm and the slanted angles of bonded surfaces on specimens of 6°, 8°, 10° and 12°. Byinvestigating experiment and analysis result of these specimens, the maximum loads are happened at 120 N, 137 N,154 N and 171 N respectively in cases of the specimens with slanted angles of 6°, 8°, 10° and 12°. As the analysisresult approach the experimental value, it is confirmed to have no much difference with the values of experiment andanalysis. It is thought that the material property can be investigated effectively on shear behavior of the materialcomposed of aluminum foam bonded with adhesive through simulation instead of experiment by applying this studymethod.

A Vitis vinifera xanthine dehydrogenase gene, VvXDH, enhances salinity tolerance in transgenic Arabidopsis

Shuang-Hong You,Bo Zhu,Feibing Wang,Hong-Juan Han,Miao Sun,Hengweng Zhu,Ri-he Peng,Quan-Hong Yao 한국식물생명공학회 2017 Plant biotechnology reports Vol.11 No.3

Xanthine dehydrogenase (EC1.1.1.204; XDH) plays an important role in purine catabolism that catalyzes the oxidative hydroxylation of hypoxanthine to xanthine and of xanthine to uric acid. Long attributed to its role in recycling and remobilization of nitrogen, recently, XDH is implicated in plant stress responses and acclimation, such research efforts, however, have thus far been restricted to Arabidopsis XDH-knockdown/knockout studies. This study, using an ectopic overexpression approach, is expected to provide novel findings. In this study, a XDH gene from Vitis vinifera, named VvXDH, was synthesized and overexpressed in Arabidopsis, the transgenic Arabidopsis showed enhanced salt tolerance. The VvXDH gene was investigated and the results demonstrated the explicit role of VvXDH in conferring salt stress by increasing allantoin accumulation and activating ABA signaling pathway, enhancing ROS scavenging in transgenic Arabidopsis. In addition, the water loss and chlorophyll content loss were reduced in transgenic plants; the transgenic plants showed higher proline level and lower MDA content than that of wild-type Arabidopsis, respectively. In conclusion, the VvXDH gene has the potential to be applied in increasing allantoin accumulation and enhancing the tolerance to abiotic stresses in Arabidopsis and other plants.

Genetic diversity and population structure analysis of Amaranth collected from the Asian region using 14 SSR markers

Cheol-Soon Park,Feng-Peng Li,Woo Ju Hong,Sun-Kyung Min,Jong Wook Chung,Yong-Jin Park 한국육종학회 2013 한국육종학회 심포지엄 Vol.2013 No.07

Amaranths (Amaranthus sp.) are cosmopolitan and include grain, vegetable, ornamental and weed types. Forteen simple sequence repeat (SSR) markers were used to analyze the genetic diversity of 59 accessions of cultivated amaranth from Asian countries. A total of 63 alleles were detected with an average of 4.5 per locus. The averaged values of gene diversity and polymorphism information content (PIC) were 0.35 and 0.33, respectively. Alleles per locus in accessions from South Asia was 4.35, whereas 2.93 and 3.79 alleles per locus were found in Nepal and India, respectively. The mean gene diversity in Central Asia and East Asia was 0.36 and 0.28, respectively, whereas the mean PIC values were 0.27 and 0.22, respectively. The genetic diversity and PIC of the India amaranths were higher than that of other Asian countries. The model-based structure analysis revealed the presence of three subpopulations, which was basically consistent with clustering based on genetic distance. An AMOVA analysis showed that the between-population component of genetic variance was less than 56.16% in contrast to 43.84% for the within-population component. The overall FST value was 0.56, reflecting genetic differentiation within Asian amaranths. These findings could be used for designing effective breeding programs aimed at broadening the genetic bases of commercially grown varieties.

VvMYBA6 in the promotion of anthocyanin biosynthesis and salt tolerance in transgenic Arabidopsis

Miao Sun,Xin-Xin Feng,Jian-Jie Ga,Ri-He Peng,Quan-Hong Yao,Liang-Ju Wang 한국식물생명공학회 2017 Plant biotechnology reports Vol.11 No.5

Transcription factor MYB is a critical factor involved in anthocyanin biosynthesis and abiotic stress resistance of plants. This paper reports the functions of codon-optimized transcription factor VvMYBA6 expressed in transgenic Arabidopsis plants. VvMYBA6 overexpression resulted in significant increase of anthocyanin content, which also enhanced salt and mannitol tolerance in transgenic Arabidopsis plants. Besides, real-time quantitative PCR (qRT-PCR) analysis showed that overexpression of VvMYBA6 promoted the expression level of genes involved in anthocyanin biosynthesis, abscisic acid (ABA) synthesis, proline synthesis, stress responses and ROS scavenging under salt and mannitol stress. According to further analysis under salt and mannitol stress, overexpression of VvMYBA6 significantly increased ABA and proline content, activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), as well as reduced the content of H2O2 and malonaldehyde (MDA). The results demonstrated that the overexpression of VvMYBA6 enhanced salt and mannitol tolerance based on increasing synthetic levels of anthocyanin and ABA in transgenic Arabidopsis plants. Therefore, the overexpression of VvMYBA6 could be widely used in promoting salt tolerance in plants.

Transcriptome analysis of rice leaves in response to Rhizoctonia solani infection and reveals a novel regulatory mechanism

De Peng Yuan,Xiao Feng Xu,Hong Woo-Jong,Si Ting Wang,Xin Tong Jia,Yang Liu,Shuang Li,Zhi Min Li,Qian Sun,Qiong Mei,Shuai Li,정기홍,Song Hong Wei,Yuan Hu Xuan 한국식물생명공학회 2020 Plant biotechnology reports Vol.14 No.5

Sheath blight disease (ShB) severely afects rice production; however, the details of defense against ShB remain unclear. To understand the rice defense mechanism against ShB, an RNA sequencing analysis was performed using Rhizoctonia solani inoculated rice leaves after 48 h of inoculation. Among them, 3417 genes were upregulated and 2532 were downregulated when compared with the control group (>twofold or<1/2). In addition, the diferentially expressed genes were classifed via Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and MapMan analyses. Fifty-nine GO terms and seven KEGG pathways were signifcantly enriched. A MapMan analysis demonstrated that the phytohormone and metabolic pathways were signifcantly altered. Interestingly, the expression levels of 359 transcription factors, including WRKY, MYB, and NAC family members, as well as 239 transporter genes, including ABC, MFS, and SWEET, were signifcantly changed in response to R. solani AG1-IA inoculation. Additionally, OsWRKY53 and OsAKT1 negatively regulate the defense response in rice against R. solani via gain of function study for OsWRKY53 and loss of function study for OsAKT1, respectively. Furthermore, several diferentially expressed genes contain R. solani-responsive cis acting regulatory elements in their promoter regions. Taken together, our analyses provide valuable information for the additional study of the defense mechanisms against ShB, and the candidate genes identifed in this study will be useful resource for future breeding to enhance resistance against ShB.

Hierarchical tumor acidity-responsive self-assembled magnetic nanotheranostics for bimodal bioimaging and photodynamic therapy

Yang, Hong Yu,Jang, Moon-Sun,Li, Yi,Fu, Yan,Wu, Te Peng,Lee, Jung Hee,Lee, Doo Sung Elsevier 2019 Journal of controlled release Vol.301 No.-

<P><B>Abstract</B></P> <P>Nanosized self-assemblies built from inorganic nanoparticles and polymer ligands have the potential to generate personalized theranostics systems for diagnostic imaging and cancer therapy. However, most of the theranostics systems suffer from poor targeting activity, insensitive diagnosis and drug leakage, leading to poor treatment results. In this study, a hierarchical tumor acidity-responsive magnetic nanobomb (termed HTAMN) was developed for photodynamic therapy and diagnostic imaging. The HTAMNs were formed through the self-assembly of chlorin e6 (Ce6)-functionalized polypeptide ligand, methoxy poly (ethyleneglycol)-block-poly (dopamine-ethylenediamine-2,3-dimethylmaleic anhydride)-L-glutamate-Ce6 [mPEG-b-P (Dopa-Ethy-DMMA)LG-Ce6] and superparamagnetic iron oxide nanoparticles (SPIONs). Negatively charged HTAMNs circulate in the blood for prolonged periods and promote tumor retention by passive targeting to the tumor. Once the HTAMNs arrive at the tumor location, the acidic extracellular tumor environment reverses the surface charge of the HTAMNs, resulting in tumor accumulation and cellular uptake. Moreover, in response to the more acidic environment inside cells, the photosensitizers are activated resulted in enhanced diagnostic imaging and cancer treatment. The in vitro and in vivo results indicate the effective tumor accumulation, internalization, diagnostic sensitivity and superior photodynamic therapy effect of the HTAMNs. Therefore, designing smart HTAMNs can promote the rapid development of cancer theranostics for clinical implementation.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>