벼 생육중기 및 출수기 태풍 "올가" 건풍에 의한 엽신 피해의 품종간 차이와 수량 및 품질 변화

윤영환,김정곤,정남진,곽강수,강양순 한국국제농업개발학회 2003 韓國國際農業開發學會誌 Vol.15 No.4

1999년 8월3일~8월4일간 태풍 올가 도래시 건풍에 의한 생육중기 엽신 피해의 품종간 차이와 출수기 이삭 갈변에 따른 수량 및 품질에 미치는 영향을 조사하여 다음과 같은 결과를 얻었다. 1. 잎의 증산량 및 수분저하속도가 클수록, 잎이 길이가 길고 폭이 넓을수록 엽신의 피해정도가 컸다. 2. 이삭의 피해 정도가 증가될수록 임실 및 등숙비율은 현저히 낮아지는 경향이며, 쌀 수량은 무피해 대비 피해 3~5는 14~16%, 피해 7은 28%, 피해 9는 48% 감수하였다. 3. 이삭의 피해 정도별 백미 완전미 비율은 피해 정도가 클수록 감소를 보였으며 피해 0~3에서 63~65%, 피해 5~9에서 42~58%의 분포를 보였다. 4. 이삭의 피해정도가 증가할수록 백도 및 색도치가 낮아지며, 단백질 함량은 증가하고 식미치는 저하하는 경향을 보였다. This study was carried out to characterize the influence of dry wind by typhoon "Olga" during Aug. 3~Aug. 4, 1999 on the rice plant(Oryza sativa L.). For the purpose, the affection of the dry wind during the mid-growing stage and heading stage on the leaf damage, yield and rice quality were investigated. The extent of the leaf damage increased with the increase of leaf size and transpiration rate, and also with the decrease of moisture content in the leaves. The percentage of fertile grain decreased in proportion to the increase of the extent of the panicle damage. Compared with none-damaged rice plants in the panicle, the milled rice yield decreased by 14~16% in the degree 3~5 of the panicle damage, and 28~48% in the degree 7~9. The percentage of head rice was the same in the both milled and brown rice in the degree 0~3 of the panicle damage. Above the degree 5, however, it decreased with the increase of the panicle damage. The whiteness and lightness decreased in proportion to the increase of the degree in the unhulled, brown and milled rice. And, there was a tendency that the protein content in the milled rice increased but eating quality decreased with the increase of the panicle damage.

Numerical study on the internal flow characteristics of an axial-flow pump under stall conditions

Kan Kan,Yuan Zheng,Yujie Chen,Zhanshan Xie,Guang Yang,Chunxia Yang 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.10

When an axial-flow pump works in low flow rate conditions, rotating stall phenomena will probably occur, and the pump will enter hydraulic unsteady conditions. The rotating stall can lead to violent vibration, noise, turbulent flow, and a sharp drop in efficiency. This affects the safety and stability of the pump unit. To study the rotating stall flow characteristics of an axial-flow pump, the steady and unsteady internal flow field in a large vertical axial-flow pump was investigated using 3D computational fluid dynamic (CFD) technology. Numerical calculations were carried out using the Reynolds-averaged Navier–Stokes (RANS) solver and Menter's shear stress transport (SST) k-ω turbulence model. Steady flow characteristics including streamline, velocity vector, pressure and turbulent kinetic energy are presented and analyzed. Unsteady flow characteristics are described using post-processing signals for pressure monitoring points in the time and frequency domains. Using Q-criterion, the locations and evolution rules of the core region of the vortex structure in guide vanes under deep stall conditions were investigated. The reliability of the numerical simulation results was verified using the experimental prototype pressure fluctuation test. In this way, typical flow structure and pressure fluctuation characteristics in an axial-flow pump were analyzed, with contrastive analysis in design condition and stall conditions. Finally, the mechanism of low-frequency pressure fluctuation in a pump unit under the stall condition was revealed.

Chemopreventive Effects of Orange Peel Extract (OPE). I. OPE Inhibits Intestinal Tumor Growth in ApcMin/+ Mice

Kan Yang,Kunhua Fan,Naoto Kurihara,Sadanori Abe,Chi-Tang Ho,Geetha Ghai 한국식품영양과학회 2007 Journal of medicinal food Vol.10 No.1

Orange peel is a rich source of flavonoids with polymethoxyflavones as major constituents, compounds asso-ciated with potential antioxidant, anti-inflammatory, and antitumor activities. We studied the effect of an orange peel extract(OPE) on intestinal tumor growth in ApcMin/. mice, a mouse model for human familial adenomatous polyposis (FAP). TheOPE contained 30% polymethoxyflavones, a mixture that included tangeretin (19.0%), heptamethoxyflavone (15.24%), tetram-ethoxyflavone (13.6%), nobiletin (12.49%), hexamethoxyflavone (11.06%), and sinensitin (9.16%). ApcMin/. mice were fedi.e., AIN-76A diet modified with decreasedcalcium, vitamin D, and methyl-donor nutrients and increased lipid content); (3) NWD with 0.25% OPE; and (4) NWD with0.5% OPE, with all additives premixed in the diet. After 9 weeks of feeding NWD to the ApcMin/. mice, tumors increasedmainly in the colon, with tumor multiplicity increasing 5.3-fold and tumor volume increasing 6.7-fold. After feeding 0.5%OPE in NWD, the development of tumors markedly decreased, with multiplicity decreasing 49% in the small intestine and38% in the colon. NWD also led to increased apoptosis in intestinal tumors, and 0.5% OPE in NWD further increased apop-model of FAP, and increased apoptosis may have contributed to this effect.

Dynamic stress of impeller blade of shaft extension tubular pump device based on bidirectional fluid-structure interaction

Kan Kan,Yuan Zheng,Shifeng Fu,Huiwen Liu,Chunxia Yang,Xin Zhang 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.4

Current research on the stability of tubular pumps is mainly concerned with the transient hydrodynamic characteristics. However, the structural response under the influence of fluid-structure interaction hasn’t been taken fully into consideration. The instability of the structure can cause vibration and cracks, which may threaten the safety of the unit. We used bidirectional fluid-structure interaction to comprehensively analyze the dynamic stress characteristics of the impeller blades of the shaft extension tubular pump device. Furthermore, dynamic stress of impeller blade of shaft extension tubular pump device was solved under different lift conditions of 0° blade angle. Based on Reynolds-average N-S equation and SST k-ω turbulence model, numerical simulation was carried out for three-dimensional unsteady incompressible turbulent flow field of the pump device whole flow passage. Meanwhile, the finite element method was used to calculate dynamic characteristics of the blade structure. The blade dynamic stress distribution was obtained on the basis of fourth strength theory. The research results indicate that the maximum blade dynamic stress appears at the joint between root of inlet side of the blade suction surface and the axis. Considering the influence of gravity, the fluctuation of the blade dynamic stress increases initially and decreases afterwards within a rotation period. In the meantime, the dynamic stress in the middle part of inlet edge presents larger relative fluctuation amplitude. Finally, a prediction method for dynamic stress distribution of tubular pump considering fluid-structure interaction and gravity effect was proposed. This method can be used in the design stage of tubular pump to predict dynamic stress distribution of the structure under different operating conditions, improve the reliability of pump impeller and analyze the impeller fatigue life.

Development and Validation of 18F-FDG PET/CT-Based Multivariable Clinical Prediction Models for the Identification of Malignancy-Associated Hemophagocytic Lymphohistiocytosis

Yang Xu,Lu Xia,Liu Jun,Kan Ying,Wang Wei,Zhang Shuxin,Liu Lei,Li Jixia,Yang Jigang 대한영상의학회 2022 Korean Journal of Radiology Vol.23 No.4

Objective: 18F-fluorodeoxyglucose (FDG) PET/CT is often used for detecting malignancy in patients with newly diagnosed hemophagocytic lymphohistiocytosis (HLH), with acceptable sensitivity but relatively low specificity. The aim of this study was to improve the diagnostic ability of 18F-FDG PET/CT in identifying malignancy in patients with HLH by combining 18F-FDG PET/CT and clinical parameters. Materials and Methods: Ninety-seven patients (age ≥ 14 years) with secondary HLH were retrospectively reviewed and divided into the derivation (n = 71) and validation (n = 26) cohorts according to admission time. In the derivation cohort, 22 patients had malignancy-associated HLH (M-HLH) and 49 patients had non-malignancy-associated HLH (NM-HLH). Data on pretreatment 18F-FDG PET/CT and laboratory results were collected. The variables were analyzed using the Mann-Whitney U test or Pearson’s chi-square test, and a nomogram for predicting M-HLH was constructed using multivariable binary logistic regression. The predictors were also ranked using decision-tree analysis. The nomogram and decision tree were validated in the validation cohort (10 patients with M-HLH and 16 patients with NM-HLH). Results: The ratio of the maximal standardized uptake value (SUVmax) of the lymph nodes to that of the mediastinum, the ratio of the SUVmax of bone lesions or bone marrow to that of the mediastinum, and age were selected for constructing the model. The nomogram showed good performance in predicting M-HLH in the validation cohort, with an area under the receiver operating characteristic curve of 0.875 (95% confidence interval, 0.686–0.971). At an appropriate cutoff value, the sensitivity and specificity for identifying M-HLH were 90% (9/10) and 68.8% (11/16), respectively. The decision tree integrating the same variables showed 70% (7/10) sensitivity and 93.8% (15/16) specificity for identifying M-HLH. In comparison, visual analysis of 18F-FDG PET/CT images demonstrated 100% (10/10) sensitivity and 12.5% (2/16) specificity. Conclusion: 18F-FDG PET/CT may be a practical technique for identifying M-HLH. The model constructed using 18F-FDG PET/CT features and age was able to detect malignancy with better accuracy than visual analysis of 18F-FDG PET/CT images.

Chemopreventive Effects of Orange Peel Extract (OPE). II. OPE Inhibits Atypical Hyperplastic Lesions in Rodent Mammary Gland

Kan Yang,Sadanori Abe,Kunhua Fan,Chi-Tang Ho,Geetha Ghai 한국식품영양과학회 2007 Journal of medicinal food Vol.10 No.1

Cancer chemoprevention via the ingestion of natural substances is a current topic of considerable interest.Flavonoids are a family of biologically active phytochemicals having a variety of biological effects. Orange peel extract (OPE)is an abundant source of polymethoxyflavones (PMFs) with potential chemopreventive properties. The OPE used here was amixture containing tangeretin (19.0%), heptamethoxyflavone (15.24%), tetramethoxyflavone (13.6%), nobiletin (12.49%),hexamethoxyflavone (11.06%), and sinensitin (9.16%). C57Bl/6 mice were fed a new “Western-style” diet (NWD), whichhad previously induced atypical hyperplasias in mammary gland, and NWD supplemented with a standardized OPE contain-OPE in NWD. After 3 months of feeding, atypical hyperplasias developed in mammary glands of mice fed NWD, but not incontrols. After feeding OPE in NWD, atypical hyperplasias per mouse decreased in frequency compared to feeding NWDalone (P. .05 in mice fed 0.25% OPE). Apoptosis increased in OPE-treated groups (P. .01) with no inhibition of mitosis.Thus, a standardized preparation of OPE with 30% PMFs decreased development of an atypical hyperplastic lesion and in-creased apoptosis in ductal epithelial cells of mouse mammary gland.

DAB Converter Based on Unified High-Frequency Bipolar Buck-Boost Theory for Low Current Stress

Kan, Jia-rong,Yang, Yao-dong,Tang, Yu,Wu, Dong-chun,Wu, Yun-ya,Wu, Jiang The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.2

This paper proposes a unified high-frequency bipolar buck-boost (UHFBB) control strategy for a dual-active-bridge (DAB), which is derived from the classical buck and boost DC/DC converter. It can achieve optimized current stress of the switches and soft switching in wider range. The UHFBB control strategy includes multi-control-variables, which can be achieved according to an algorithm derived from an accurate mathematical model. The design method for the parameters, such as the transformer turns ratio and the inductance, are shown. The current stress of the switches is analyzed for selecting an optimal inductor. The analysis is verified by the experimental results within a 500W prototype.

Fatigue assessment of the propulsion shafting system in eco-ships with an engine acceleration problem

Yang-Gon Kim,Kwon-Hae Cho,Ue-Kan Kim 한국마린엔지니어링학회 2017 한국마린엔지니어링학회지 Vol.41 No.5

Doping BiFeO₃: approaches and enhanced functionality

Yang, Chan-Ho,Kan, Daisuke,Takeuchi, Ichiro,Nagarajan, Valanoor,Seidel, Jan The Royal Society of Chemistry 2012 Physical chemistry chemical physics Vol.14 No.46

<P>BiFeO<SUB>3</SUB> is one of the most studied multiferroic materials. Both its magnetic and ferroelectric properties can be influenced by doping. A large body of work on the doped material has been presented in the past couple of years. In this paper we provide a perspective on general doping concepts and their impact on the material's functionality.</P> <P>Graphic Abstract</P><P>This paper provides a perspective on general doping concepts of multiferroic BiFeO<SUB>3</SUB> and their impact on the material's functionality. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2cp43082g'> </P>

Effects of torsional vibration of a propulsion shafting system using a large-scale two stroke marine engine with a waste heat recovery system

Yang-Gon Kim,Kwon-Hae Cho,Ue-Kan Kim 한국마린엔지니어링학회 2017 한국마린엔지니어링학회지 Vol.41 No.5