The Dynamic Mechanical Properties for Recycled Aggregate Concrete under Tensile-Compressive States

Zhen-Jun He,Zhi-qiang Wang,Meng-jia Ding,Zhen-wei Wang,Xiao-jie Zhang,Lian-shuo Liu 대한토목학회 2020 KSCE Journal of Civil Engineering Vol.24 No.5

The experiments under biaxial tensile-compressive (T-C) complex stress were carried out for two kinds of substitution percentages of recycled coarse aggregate (RCA) on biaxial proportional loading (α = σ1:σ3 =1:0, 0: -1, 0.05: -1, 0.1: -1, 0.25: -1, 0.5: -1, 1: -1 and-1: -1) and four loading deformation rates of 10−5/s, 10−4/s , 10−3/s, and 10−2/s. The research was completed in the static-dynamic true triaxial machine. The experimental phenomena indicate the tensile failure appears in these specimens of recycled aggregate concrete (RAC) under biaxial T-C stress states. The dynamic mechanical behavior for RAC under biaxial T-C loadings was affected by the strain rates, stress ratios and its substitution percentages of RCA. Accompanied by the increase of strain rates, its strength of RAC is improved. As the tensile stress increases, its compressive strength decreases. The T-C strengths for RAC under biaxial T-C states are less than its corresponding uniaxial T-C strengths at a certain identical strain rates, respectively. Considering the effect of loading rates, a new tensile-compressive failure criterion is established under complex stress states.

Highlights of China's Biotechnology

Meng Guang Zhen,Huang Wang Yi 한국미생물생명공학회(구 한국산업미생물학회) 1994 제2차 한.중 생명공학 심포지움 Vol.- No.-

Preparation and activity evaluation of chrysin-b-Dgalactopyranoside

Zhen-Yuan Zhu,Ling Chen,Fei Liu,Li-Jing Chen,Meng Meng,Hui-Qing Sun,Yong-Min Zhang 대한약학회 2016 Archives of Pharmacal Research Vol.39 No.10

Chrysin-b-D-galactopyranoside was efficiently synthesized, evaluated for its inhibitory activities against H22 cell lines compared with chrysin, the scavenging of hydroxyl radical, DPPH radical and superoxide anion, inhibitory effect against bacteria and fungi. The structures of all compounds were fully characterized by spectroscopic data (NMR, MS). The anti-tumor, antioxidant and antimicrobial activities of chrysin-b-D-galactopyranoside were proved to be enhanced significantly compared with chrysin.

Multiparametric Functional Magnetic Resonance Imaging for Evaluating Renal Allograft Injury

Yuan Meng Yu,Qian Qian Ni,Zhen Jane Wang,Meng Lin Chen,Long Jiang Zhang 대한영상의학회 2019 Korean Journal of Radiology Vol.20 No.6

Kidney transplantation is the treatment of choice for patients with end-stage renal disease, as it extends survival and increases quality of life in these patients. However, chronic allograft injury continues to be a major problem, and leads to eventual graft loss. Early detection of allograft injury is essential for guiding appropriate intervention to delay or prevent irreversible damage. Several advanced MRI techniques can offer some important information regarding functional changes such as perfusion, diffusion, structural complexity, as well as oxygenation and fibrosis. This review highlights the potential of multiparametric MRI for noninvasive and comprehensive assessment of renal allograft injury.

《牡丹亭》場上表演的几个問題

蔡孟珍(Cai Meng-Zhen) 중국문화연구학회 2004 중국문화연구 Vol.0 No.5

《牧丹亭》 은 中國 明代의 湯顯祖의 “四夢” 가운데 유명한 戱曲作品으로 오늘날까지 공연되어지고 있다. 그런데 다양한 판본을 지니고 있어서 그 공연형태도 다양성을 띄고 있다. 필자는 공연의 다양성 가운데 특히 中國古典 戱曲의 중요한 특징이라고 할 수 있는 음률방면에 주안점을 두고 논지를 펼쳤다. 우선 音律的인 측면에서 海鹽腔과 관련이 있음을 밝혀 내었으며, 아울러 崑山腔의 상관관계도 규명해 내었다. 이러한 점은 《모란정》이 뛰어난 문사에 비해서 음률이 다소 성취도가 떨어지는 원인도 찾아낼 수 있었다. 다음으로 《모란정》이 무대에서 상연되는 과정에서 이루어진 改作의 문제도 연구하여 당시의 사회적 환경 및 관중의 심미의식과의 관계성도 살퍼보았다.

Wind-Induced Vibration Responses of Prestressed Double-Layered Spherical Latticed Shells

Zhen Zhou,Zhi-ming Li,Shao-ping Meng,Jing Wu 한국강구조학회 2011 International Journal of Steel Structures Vol.11 No.2

This paper focuses on the wind-induced vibration response of prestressed double-layered spherical latticed shell (PDSLS)structures by adopting time-domain analysis method. Welch spectrum analysis method is used to make precision evaluation of power spectrum of fluctuating wind speed time history simulated by weighted amplitude wavelet superposition (WAWS)method and linear filtering method of auto-regression (AR) model. Results show that the two methods produce little precision difference, but AR method is far more efficient than WAWS and is more suitable for wind speed simulation of PDSLSs. The effect of various parameters on the wind-induced vibration response of PDSLS structures are comprehensively investigated,including rise-span ratio, span, shell thickness, elastic constraint stiffness, prestress value, with or without cables and cable layout scheme. Results show that rise-span ratio and span are the major factors that affect wind-induced vibration response of PDSLSs. When cables are set, the wind vibration coefficient of nodal vertical displacement becomes smaller and more equally distributed, which demonstrates that PDSLSs are less sensitive to fluctuating wind effect than common latticed shell structures without cables. Finally, based on the envelopment concept and with the maximum dynamic and average wind-induced displacement responses as control indicators, the calculating method for global wind vibration coefficient (GWVC) of PDSLSs is proposed and the value with usual design parameters is given. Meanwhile, when the structure is made static analysis by means of the equivalent static wind load obtained from GWVC, the obtained internal member force response is relatively accordant with the actual response got from time-history analysis, and is a little safer.

Adaptive Algorithm in Image Reconstruction Based on Information Geometry

( Meng Wang ),( Zhen Hu Ning ),( Jing Yu ),( Chuang Bai Xiao ) 한국인터넷정보학회 2021 KSII Transactions on Internet and Information Syst Vol.15 No.2

Compressed sensing in image reconstruction has attracted attention and many studies are proposed. As we know, adding prior knowledge about the distribution of the support on the original signal to CS can improve the quality of reconstruction. However, it is still difficult for a recovery framework adjusts its strategy for exploiting the prior knowledge efficiently according to the current estimated signals in serial iterations. With the theory of information geometry, we propose an adaptive strategy based on the current estimated signal in each iteration of the recovery. We also improve the performance of existing algorithms through the adaptive strategy for exploiting the prior knowledge according to the current estimated signal. Simulations are presented to validate the results. In the end, we also show the application of the model in the image.

Analysis of common and characteristic actions of Panax ginseng and Panax notoginseng in wound healing based on network pharmacology and meta-analysis

Zhen Wang,Xueheng Xie,Mengchen Wang,Meng Ding,Shengliang Gu,Xiaoyan Xing,Xiaobo Sun 고려인삼학회 2023 Journal of Ginseng Research Vol.47 No.4

Fire-Induced Failure of Long-Term Service and Fresh Concrete Beams Subjected to Fire

Meng Wang,Zhen Guo,Xiaoyan Jia,Yue Yin,Chuang Ma 대한토목학회 2021 KSCE Journal of Civil Engineering Vol.25 No.10

In engineering, reinforced concrete beams are subjected to natural erosion and the working stress state. However, previous studies regarding structural fire have focused on new concrete beams, and most results are obtained from no-stress-state tests. Hence, research that considers the natural erosion and working stress states of beam members in fire is lacking. In this study, fire experiments were performed to investigate the differences between long-term service concrete beams and new elements under loads. A technique using ARAMIS three-dimensional (3D) optical strain measurement was adopted; it provides increased sample throughput and 3D measurements that indicate the change in strain more intuitively. Results show that the moisture content of concrete determines the spalling degree of concrete under the influence of working stress. With the increase of concrete moisture content, the range of temperature of heated and backfire surface increases and the spalling phenomenon is more obvious, especially when the moisture content exceeds 2.5%. In addition, the long-term service specimens are affected by fire more easily, thereby accelerating the destruction process owing to the degree of carbonation.

Conceptual design for a multi-rotor UAV based on variable paddle pitch

Zhen Qin,Xiaoran Tang,Ziqi Meng,Yu-Ting Wu,류성기,Yue Wang 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.10

The field of unmanned aerial vehicles has experienced a "golden era" of progress in recent years (UAV). UAVs come in a vast variety, from the commercial to the military sectors. The UAVs available today are tiny, mini multirotor devices. The advantages of the small multi-rotor structure are its small size, straightforward design, high hovering effectiveness, adaptability in changing directions, and quick flight speed. For activities like tracking and aerial photography, it is especially useful. However, the majority of multi-rotor UAVs, according to current UAV offers, are built around cameras and sensors. As a result, they can't complete other kinds of missions due to their large overall size, light weight, and small cargoes. The outbreak has sparked interest in and study into whether contactless distribution and logistics are practical. Unmanned mechanical devices for various rescue and specialized duties are also being researched by organizations. Therefore, a medium to big multi-rotor UAV needs to be researched and developed. The assembly of paddle holders and auto-tilters for medium- to large-sized multi-rotor UAVs is examined in this work. The multi-rotor UAV is intended to mount an auto-tilter. Its component strength checks are analyzed. Additionally, the blade requirements are chosen, along with strength tests of the individual components, and the structural design of the UAV rotor system is provided. The mechanical viability of the UAV is then confirmed using a motion simulation of its mechanical design.