Mesh Simplification Using Vertex Clustering Based on Principal Curvature

Zhen Hua,Zilong Huang,Jinjiang Li 보안공학연구지원센터 2015 International Journal of Multimedia and Ubiquitous Vol.10 No.9

(PhIO)n Mediated Annulations of Aromatic Aldehyde N-Acylhydrazones for the Synthesis of 1,3,4-Oxadiazoles

Zhenhua Shang,Jing Ha,Xiao Tao,Longpeng Xu,Qing Liu,Pan Wang 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.6

Optimal Design and Performance of Plate Heat Exchanger Applied in Fresh Water Generator System

ZhenHua Jin,GiTae Park(박기태),HanShik Chung(정효민),HyoMin Jeong(정한식),SoonHo Choi(최순호) 한국동력기계공학회 2007 한국동력기계공학회 학술대회 논문집 Vol.- No.-

Heat exchanger device are essential components in complex engineering systems related to energy transformation in industrial scenarios. Plate heat exchangers(PHE) are an important part of a condensing or evaporating system. This paper presents a review of plate heat exchanger. Among many of factor which should to concentrate on, the heat transfer and Pressure drop is most important part during sizing and rating the performance of PHE. Finally, the fresh water generator applied PHE will performed in future. Fresh Water Generators or Desalinate are installed in ship to convert the seawater from sea to freshwater using the heat from the engines. This paper serve as a starting for further research. Thus, extensive experiment and analysis is required to study the thermal and fluid flow characteristics of PHE.

A Study of Mixing System Using Gas-Liquid Ejector

ZhenHua Jin,YouSin Jun,Tony Suryo Utomo,XueSong Li,HanShik Chung,HyoMin Jeong 한국동력기계공학회 2006 한국동력기계공학회 학술대회 논문집 Vol.- No.-

A literature review has been carried out on reactor using gas-liquid ejector. The aim of this paper is further studies to achieve deeper understanding in this field. First to investigate the influence of operating conditions and design parameters on the hydrodynamics and the mass transfer properties of a loop reactor. This paper provides a literature review on the ejectors applications in the mixing system. A number of studies are grouped and discussed in several topics. Such as the background, theory of ejector, mixing characteristics, optimization of the system. Since the high efficiencies reactor using ejector widely used in gas-liquid system, especially in a number of chemical and biochemical processes. This is due to their high efficiency in gas dispersion resulting in high mass transfer rate and low power requirements. Circulation and gas dispersion are achieved when the liquid is injected into the reactors with high velocity which entrain the gas phase and create a fine dispersion of the two phases. Thus ejector has been applied to the mixing system.

Ginger and Its Pungent Constituents Non-Competitively Inhibit Serotonin Currents on Visceral Afferent Neurons

Zhenhua Jin,Goeun Lee,Sojin Kim,Cheung-Seog Park,Yong Seek Park,Young-Ho Jin 대한생리학회-대한약리학회 2014 The Korean Journal of Physiology & Pharmacology Vol.18 No.2

Nausea and emesis are a major side effect and obstacle for chemotherapy in cancer patients. Employ of antiemetic drugs help to suppress chemotherapy−induced emesis in some patients but not all patients. Ginger, an herbal medicine, has been traditionally used to treat various kinds of diseases including gastrointestinal symptoms. Ginger is effective in alleviating nausea and emesis, particularly, for cytotoxic chemotherapy drug−induced emesis. Ginger-mediated antiemetic effect has been attri-buted to its pungent constituents-mediated inhibition of serotonin (5-HT) receptor activity but its cellular mechanism of action is still unclear. Emetogenic chemotherapy drugs increase 5-HT concen-tration and activate visceral vagal afferent nerve activity. Thus, 5-HT mediated vagal afferent activation is essential to provoke emesis during chemotherapy. In this experiment, water extract of ginger and its three major pungent constituent’s effect on 5-HT−evoked responses were tested on acutely dispersed visceral afferent neurons with patch-clamp methods. The ginger extract has similar effects to antiemetic drug ondansetron by blocking 5-HT−evoked responses. Pungent constituents of the ginger, [6]-shogaol, [6]-gingerol, and zingerone inhibited 5-HT responses in a dose dependent manner. The order of inhibitory potency for these compounds were [6]-shogaol>[6]-gingerol>zingerone. Unlike well-known competitive 5-HT₃ receptor antagonist ondansetron, all tested ginger constituents acted as non-competitive antagonist. Our results imply that ginger and its pungent constituents exert antiemetic effects by blocking 5-HT−induced emetic signal transmission in vagal afferent neurons.

Fracture Properties of Wide-Notch Concrete Beams strengthened with Near-Surface Mounted CFRP Rebar

Zhenhua Ren,Xiantao Zeng,Junbo Sun,Jun Wang 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.11

Carbon fiber reinforced polymer (CFRP) is a promising engineering material nowadays. This study carried out four-point-bending fracture experiment on wide-notch-concrete beams reinforced with near-surface mounted (NSM) CFRP rebar, aiming at exploring the effect of CFRP rebar on beam fracture characteristics. The test comprised four groups concrete beam specimens (three for each) with varying reinforcing methodologies. The first group specimens were common concrete beams strengthened by one near-surface mounted CFRP bar, while the second group consisted of common concrete beams strengthened by two near-surface mounted CFRP bars. On the issue of the third group, there were three wide-notch concrete beams strengthened with one near-surface mounted CFRP bar. Lastly, three wide-notch concrete beams strengthened with two near-surface mounted CFRP bars form the group four. The study proposed various equations about the rectangular concrete beams strengthened with near-surface mounted CFRP rebar under tension-shearing condition. For both open cracks and closed cracks, the equations concluded stress intensity factor as well as extending angle in mode I and II crack types. Four-point-bending fracture experiments for wide-notch-concrete beams and numerical simulation experiments were included in this research. This research exhibited expanding direction of wing type crack under effective shearing stress by the superposition model of crack tip stress intensity factor and stress intensity factor. Four-point-bending fracture tests for wide-notch-concrete beams and numerical simulation tests are finished in this research. The tests demonstrate characteristics of crack expanding direction, extending angle, vertical displacement, maximum normal stress, shear strain rate, distribution of plastic zones. Combining the theory and reality, the experimental results were in close agreement with the numerical research.

Deformation and failure mechanism exploration of surrounding rock in huge underground cavern

Zhenhua Tian,Jian Liu,Xiaogang Wang,Lipeng Liu,Xiaobo Lv,Xiaotong Zhang 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.72 No.2

In a super-large underground with “large span and high side wall”, it is buried in mountains with uneven lithology, complicated geostress field and developed geological structure. These surrounding rocks are more susceptible to stability issues during the construction period. This paper takes the left bank of Baihetan hydropower station (span is 34m) as a case study example, wherein the deformation mechanism of surrounding rock appears prominent. Through analysis of geological, geophysical, construction and monitoring data, the deformation characteristics and factors are concluded. The failure mechanism, spatial distribution characteristics, and evolution mechanism are also discussed, where rock mechanics theory, FLAC3D numerical simulation, rock creep theory, and the theory of center point are combined. In general, huge underground cavern stability issues has arisen with respect to huge-scale and adverse geological conditions since settling these issues will have milestone significance based on the evolutionary pattern of the surrounding rock and the correlation analyses, the rational structure of the factors, and the method of nonlinear regression modeling with regard to the construction and development of hydropower engineering projects among the worldwide.

Splanchnic nerve neurolysis via the transdiscal approach under fluoroscopic guidance: a retrospective study

( Zhenhua Cai ),( Xiaolin Zhou ),( Mengli Wang ),( Jiyu Kang ),( Mingshuo Zhang ),( Huacheng Zhou ) 대한통증학회 2022 The Korean Journal of Pain Vol.35 No.2

Background: Neurolytic celiac plexus block (NCPB) is a typical treatment for severe epigastric cancer pain, but the therapeutic effect is often affected by the variation of local anatomical structures induced by the tumor. Greater and lesser splanchnic nerve neurolysis (SNN) had similar effects to the NCPB, and was recently performed with a paravertebral approach under the image guidance, or with the transdiscal approach under the guidance of computed tomography. This study observed the feasibility and safety of SNN via a transdiscal approach under fluoroscopic guidance. Methods: The follow-up records of 34 patients with epigastric cancer pain who underwent the splanchnic nerve block via the T11-12 transdiscal approach under fluoroscopic guidance were investigated retrospectively. The numerical rating scale (NRS), the patient satisfaction scale (PSS) and quality of life (QOL) of the patient, the dose of morphine consumed, and the occurrence and severity of adverse events were recorded preoperatively and 1 day, 1 week, 1 month, and 2 months after surgery. Results: Compared with the preoperative scores, the NRS scores and daily morphine consumption decreased and the QOL and PSS scores increased at each postoperative time point (P < 0.001). No patients experienced serious complications. Conclusions: SNN via the transdiscal approach under flouroscopic guidance was an effective, safe, and easy operation for epigastric cancer pain, with fewer complications.

Wake effects of an upstream bridge on aerodynamic characteristics of a downstream bridge

Zhenhua Chen,Zhenyun Lin,Haojun Tang,Yongle Li,Bin Wang 한국풍공학회 2019 Wind and Structures, An International Journal (WAS Vol.29 No.6

To study the wake influence of an upstream bridge on the wind-resistance performance of a downstream bridge, two adjacent long-span cable-stayed bridges are taken as examples. Based on wind tunnel tests, the static aerodynamic coefficients and the dynamic response of the downstream bridge are measured in the wake of the upstream one. Considering different horizontal and vertical distances, the flutter derivatives of the downstream bridge at different angles of attack are extracted by Computational Fluid Dynamics (CFD) simulations and discussed, and the change in critical flutter state is further studied. The results show that a train passing through the downstream bridge could significantly increase the lift coefficient of the bridge which has the same direction with the gravity of the train, leading to possible vertical deformation and vibration. In the wake of the upstream bridge, the change in lift coefficient of the downstream bridge is reduced, but the dynamic response seems to be strong. The effect of aerodynamic interference on flutter stability is related to the horizontal and vertical distances between the two adjacent bridges as well as the attack angle of incoming flow. At large angles of attack, the aerodynamic condition around the downstream girder which may drive the bridge to torsional flutter instability is weakened by the wake of the upstream bridge, and the critical flutter wind speed increases at this situation.

Effect of Vibration of Flexible Transducer on Shear Resistance of Scaling in Tunnel Drainage

Zhenhua Xin,문준호,김영욱 대한토목학회 2017 KSCE JOURNAL OF CIVIL ENGINEERING Vol.21 No.5

Through a series of laboratory tests, an investigation was conducted into the reduction of shear resistance of scale in tunnel drainage through the use of wave energy. A flexible transducer was used to generate vibration and emitted it through a polyvinylidene fluoride polymer film as various frequencies. Tests were conducted using specially designed and fabricated equipment. The results of the study showed a significant decrease in shear resistance when sonication was applied. The degree of reduction varied by frequency. Using the test results, we discuss the potential development of a new maintenance system method for drainage.