Experimental Studies on Progressive Collapse Behavior of RC Frame Structures: Advances and Future Needs

Wei?Jian Yi,Fan Yi,Yun Zhou 한국콘크리트학회 2021 International Journal of Concrete Structures and M Vol.15 No.4

In the recent two decades, the progressive collapse of reinforced concrete (RC) frame structures attracted unprecedented research interests in the structural engineering community. Experiments are regarded as an essential method in this field since actual cases can barely provide sufficient and effective data to support rigorous research. In this paper, prevailing experimental assumptions and configurations among over 100 series of experiments are quantitatively revealed by a bibliometric collection based on systematic search in an academic database. Since numerous experiments have been reported on the progressive collapse of RC frame structures, this paper subsequently presents a state-of-the-art review summarizing both experimental consensuses and controversies constituted by three main aspects: (a) static mechanisms, (b) dynamic behavior, and (c) threat-dependent research. The significance of secondary mechanisms, existing problems of dynamic effects, and potential flaws of the threat-independent assumption are discussed in detail with experimental findings. Future needs are emphasized on research targets, correlations between experiments and design, dynamic effects, threat-dependent issues, and retrofitting. These recommendations might help researchers or designers realize a more reliable and realistic progressive collapse design of RC frame structures in the future.

Removal of Cd(II) by poly(styrenesulfonic acid)-impregnated alginate capsule

Wei, Wei,Bediako, John Kwame,Kim, Sok,Yun, Yeoung-Sang ELSEVIER SCIENCE B.V.; AMSTERDAM 2016 JOURNAL- TAIWAN INSTITUTE OF CHEMICAL ENGINEERS Vol.61 No.-

<P><B>Abstract</B></P> <P>In this study, a capsule type sorbent of poly(styrenesulfonic acid)-impregnated alginate capsule (PSSA-AC) was developed by using a simple and moderate method. PSSA was used as a model encapsulated material because of its large number of sulfonic acid groups which have high affinity toward Cd(II). PSSA-AC was prepared by dropping solution A (mixture of 10% (w/v) PSSA + 1% CaCl<SUB>2</SUB>) into B solution (0.6% (w/v) sodium alginate). Microscope images revealed that PSSA was well encapsulated inside of the alginate shell. The pH edge experiment indicated that Cd(II) sorption was influenced marginally by the experimental pH range. The maximum Cd(II) uptake by PSSA-AC was as high as 184.12 ± 6.30 mg/g. The kinetic and FTIR studies demonstrated that ion-exchange was the main sorption mechanism. The PSSA-AC could be regenerated by using 2% CaCl<SUB>2</SUB> as a desorbing agent.</P> <P><B>Highlights</B></P> <P> <UL> <LI> PSSA-AC was successfully developed using a simple and moderate method. </LI> <LI> The maximum Cd(II) uptake was 184.12 ± 6.30 mg/g using Langmuir isotherm model. </LI> <LI> The Cd(II)-loaded PSSA-AC was easily regenerated by using 2% CaCl<SUB>2</SUB> solution. </LI> <LI> The overall sorption/desorption mechanism was cation ion-exchange between Cd(II) and Ca(II). </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Design of a Low Cost General Purpose Neuro-Computer

Yun Wei,Liyan Wang,Shoujue Wang 대한전자공학회 1994 ICONIP : International Conference On Neural Inform Vol.3 No.1

FingerTalk: Real-time Fingertip Trajectories Tracking Service based on IoTtalk

Yun-Wei Lim,Lin-Hang Kao,Chun-Ting Yeh 한국통신학회 2020 한국통신학회 APNOMS Vol.2020 No.09

Internet of Things (IoT) integrates with finger tracking and 3D signature verification can provide the user authentication service for these IoT applications which require user identification and authorization, such as the home automation and security system. This work develops two modules. The FingerTalk module provides the fingertip trajectories tracking service based on a Leap Motion camera and IoTtalk. The AirSig module provides 3D signature verification service to recognize whether a signature is signed form the authenticated user. The AirSig module requires only two user signature samples to train the neural network model which significantly reduces the process time for signature collection. The validation results from 10 people show the average accuracy is up to 93.6% on 3D signature verification.

Temperature Compensation Technique for Steel Sleeve Packaged FBG Strain Sensor and Its Application in Structural Monitoring

Yun, Ying-Wei,Jang, Il-Young Korean Society of Hazard Mitigation 2008 한국방재학회논문집 Vol.8 No.6

As bare Fiber Bragg Grating (FBG) sensors are very fragile, bare FBG without encapsulation is not properly applied in practical infrastructures directly due to the harsh environment in practical engineering. Steel sleeve packaged FBG strain sensor is widely used in civil engineering. Since FBG senses both strain and temperature simultaneously, for accurate measurement of strain, temperature compensation for FBG strain sensors is indispensable. In this paper, based on the FBG's strain and temperature sensing principles, the temperature compensation techniques for steel sleeve packaged FBG sensors are brought forward. And the experiment of concrete early-age shrinkage monitoring by dual FBG sensors is carried out to test the feasibility of the temperature compensation technique. 피복이 없는 FBG센서는 내구성이 매우 약하기 때문에 FBG센서 주위의 피복이 없이는, 많은 변수가 존재하는 실제 자연환경에서의 정확한 데이터수집이 어렵다. Steel sleeve packaged FBG 변형률 센서는 토목공학에서 널리 사용되고 있는 센서 중 하나이다. 변형률과 온도가 동시에 측정되는 FBG센서의 도입 이후로, 변형률과 온도의 정확한 보정은 필수적인 과정이 되었다. 이 논문에서는 FBG의 변형률과 온도의 측정 원리에 기초하여 steel sleeve packaged FBG센서의 온도보정 기술을 도출하였다. 그리고 두개의 FBG센서를 이용한 콘크리트 초기재령의 건조수축 실험을 통해 온도보정의 실행 가능성을 확인하였다.

Early Age Properties of HPC Columns under Construction-Site Conditions

Yun, Ying-Wei,Jang, Il-Young Korea Concrete Institute 2008 International Journal of Concrete Structures and M Vol.2 No.1

High performance concrete (HPC) is widely used in civil engineering due to its high durability and low permeability etc. Compared with ordinary concrete, HPC may develop much higher AS (autogenous shrinkage) at early age due to the relative low water cement (w/c) ratio and adding of mineral admixtures, which is one of the main reasons for early age micro-cracking of HPC structures. This paper studies the early age property of HPC columns under similar construction-site surroundings by embedded strain transducers. Results show that for HPC structure, early-age autogenous shrinkage especially within the first day after concrete pouring is pretty large. AS within the first day are 60% larger than those for 14 days in this research for all specimens. Therefore it should be taken into account for structure durability. By comparison of PHPC (plain HPC column) and RHPC (reinforced HPC column) specimens, the effects of reinforced bars on AS and temperature distribution have been analyzed. Also the influence of w/c ratio on AS is demonstrated.

Design of a Low Cost General Purpose Neuro-Computer

Yun Wei,Liyan Wang,Shoujue Wang 대한전자공학회 1994 ICONIP : International Conference On Neural Inform Vol.3 No.2

AT1 Receptor Modulator Attenuates the Hypercholesterolemia-Induced Impairment of the Myocardial Ischemic Post-Conditioning Benefits

Yun-Wei Li,Yan-Ming Li,Yan Hon,Qi-Lin Wan,Rui-Li He,Zhi-Zhong Wang,Cui-Hua Zhao 대한심장학회 2017 Korean Circulation Journal Vol.47 No.2

Background and Objectives: Ischemic post-conditioning (PostC) has been demonstrated as a novel strategy to harness nature’s protection against myocardial ischemia-reperfusion (I/R). Hypercholesterolemia (HC) has been reported to block the effect of PostC on the heart. Angiotensin II type-1 (AT1) modulators have shown benefits in myocardial ischemia. The present study investigates the effect of a novel inhibitor of AT1, azilsartan in PostC of the heart of normocholesterolemic (NC) and HC rats. Materials and Methods: HC was induced by the administration of high-fat diet to the animals for eight weeks. Isolated Langendorff’s perfused NC and HC rat hearts were exposed to global ischemia for 30 min and reperfusion for 120 min. I/R-injury had been assessed by cardiac hemodynamic parameters, myocardial infarct size, release of tumor necrosis factor-alpha troponin I, lactate dehydrogenase, creatine kinase, nitrite in coronary effluent, thiobarbituric acid reactive species, a reduced form of glutathione, superoxide anion, and left ventricle collagen content in normal and HC rat hearts. Results: Azilsartan post-treatment and six episodes of PostC (10 sec each) afforded cardioprotection against I/R-injury in normal rat hearts. PostC protection against I/R-injury was abolished in HC rat hearts. Azilsartan prevented the HC-mediated impairment of the beneficial effects of PostC in I/R-induced myocardial injury, which was inhibited by L-N5-(1-Iminoethyl)ornithinehydrochloride, a potent inhibitor of endothelial nitric oxide synthase (eNOS). Conclusion: Azilsartan treatment has attenuated the HC-induced impairment of beneficial effects of PostC in I/R-injury of rat hearts, by specifically modulating eNOS. Azilsartan may be explored further in I/R-myocardial injury, both in NC and HC conditions, with or without PostC.

Cytotoxic and anti-inflammatory activities of phenanthrenes from the medullae of Juncus effusus L.

Wei Ma,Yue Zhang,Yun-Yun Ding,Feng Liu,Ning Li 대한약학회 2016 Archives of Pharmacal Research Vol.39 No.2

Bioactivity guided phytochemical investigation of the ethanol extract of the medullae of Juncus effusus resulted in the isolation of two new phenanthrenes, 8-hydroxymethyl-2- hydroxyl-1-methyl-5-vinyl-9,10-dihydrophenanthrene (1), and 5-(1-methoxyethyl)-1-methyl-phenanthren-2,7-diol (2) together with 15 known phenanthrenoids (3–17). The chemical structures of 1 and 2 were established by a combination of spectroscopic techniques. Compounds 1–15 and 17 were evaluated for their cytotoxic activities against five human cancer cell lines (SHSY-5Y, SMMC-7721, HepG-2, Hela and MCF-7) by CCK-8 assay, and their anti-inflammatory activities were also evaluated by inhibition on NO production in LPSactivated murine macrophage RAW 264.7 cells.

Recent progresses in marine microbial-derived antiviral natural products

Yun‑Fei Teng,Li Xu,Mei‑Yan Wei,Chang‑Yun Wang,Yu‑Cheng Gu,Chang‑Lun Shao 대한약학회 2020 Archives of Pharmacal Research Vol.43 No.12

Viruses have always been a class of pathogenicmicroorganisms that threaten the health and safety of humanlife worldwide. However, for a long time, the treatment ofviral infections has been slow to develop, and only a fewantiviral drugs have been using clinically. Compared withthese from terrestrial environments, marine-derived microorganismscan produce active substances with more novelstructures and unique functions. From 2015 to 2019, 89antiviral compounds of 8 structural classes have been isolatedfrom marine microorganisms, of which 35 exhibit anti-H1N1 activity. This review surveys systematically marinemicrobial-derived natural products with antiviral activityand illustrates the impact of these compounds on antiviraldrug discovery research.