고속액체크로마토그래피에 의한 나프록센 광학이성질체의 분리 및 품질관리

정수진,진전성,이은주,이은실,강종성 忠南大學校 生命科學硏究院 醫藥品開發硏究所 2006 藥學論文集 Vol.21 No.-

Enantiomeric separation of naproxen is necessary in drug evaluation processes as the pharmacological activity of naproxen resides mainly in the (S)-enantiomer, The enantioseparation of naproxen was carried out with three different stationary phases. The methods were validated with the terms of linearity, intraday and interday precision, accuracy, selectivity and recovery. Among the selected stationary phases, ChiroSil DMB column with hexane : t-butylmethylether : acetic acid (60:40:0.1, v/v/v) as mobile phase showed the best enantioseparation of the naproxen in the commercial preparations. The wavelength for detection was 270 nm and flow rate was 2.0 mL/min. The contents of (S)-naproxen in the commercial preparations were 92.7 - 98.3%, indicating that all tested preparations were satisfactory to current regulation. However, the contents of (R)-naproxen as impurity in the commercial preparations were varied from 0.08% to 1.08%.

6LoWPAN에서 딕스트라 알고리즘을 이용한 에너지 효율적인 라우팅 프로토콜

진소,김중규 대구대학교 정보통신연구소 2010 情報通信硏究 Vol.7 No.1

최근에 IEEE 802.15.4 프로토콜은 데이터 전송 속도가 낮은 무선 통신을 위한 표준 프로토콜로 채택되었다. 서비스의 이용 확산과 센서 네트워크의 관리를 용이하기 위해 IETF 6LoWPAN(IPv6 over Low power WPAN) WG에서는 IEEE 802.15.4 MAC/PHY 상위 계층에 IPv6를 기존 인터넷에서 사용가능 한 무선통신 프로토콜에 대한 표준화 작업을 진행하고 있다. 센서 네트워크에서 노드간의 통신을 위한 라우팅 프로토콜은 AODV, LOAD, DYMO-low 등을 사용하고 있는데, 이러한 라우팅 프로토콜들은 에너지를 고려하지 않기 때문에 센서 네트워크에 그대로 적용하면 에너지 효율적 측면에서 문제점이 발생한다. 따라서 본 연구에서는 에너지 효율적인 라우팅 프로토콜로 DAODV을 제안하고자 한다. 이 방법에서는 노드 에너지 잔량 값을 이용하여 그 라우팅 경로비용이 결정되면 딕스트라 알고리즘을 적용하여 각 노드의 에너지에 대한 최단경로를 선택한다. The IEEE 802.15.4 protocol in the wireless communications technology, which is defined low-data-rate in a wireless personal area network. In order to expand the services and facilitate the management of sensor networks, IETF 6LoWPAN(IPv6 over Low power WPAN) WG by integrating IPv6 with Low-Rate Wireless Personal Area Newtork, which in the IEEE 802.15.4 MAC/PHY upper layer of IPv6, in order to used in the benchmark Internet, is being a standardized wireless communication protocol. For the communication between nodes in sensor network there are AODV, LOAD, DYMO-low routing protocols. However, these routing protocols do not consider the energy, the same problem occurs in terms of energy efficient. For these reasons, energy efficient routing protocol in this research to have suggested DAODV. Using nodes remanent energy, and if the cost of the routing path is determined, each node on the energy of the shortest path by applying the Dijkstra algorithm should calculate and communications.

小麥의 稈長 遺傳에 관한 연구

曺章煥,吳正行,蔡濟天,鄭吉雄,金鳳九 단국대학교 1992 論文集 Vol.26 No.-

This study has been conducted to investigate the genetic and ecological variation of wheat culm length measured from those plants grown at greenhouse. The results are as following. 1. The clum length of the winter wheat was higest under 12hrs daylength, while that of the spring wheat was highest under 8hrs daylength. Standard errors of culm length was larger under 12 and 8hrs daylength than that of 24hrs daylength condition. 2. The culm length was shortest under the 24hrs daylength compare to under 12 or 8hrs while it was highest under 12hrs. Short and medium culm length varieties were photo-insensitive but those of long culm length were photo-sensitive. 3. There are many types of varietal differences for the culm length under the daylength conditions. Highest culm length group under 12 and 8hrs conditions was classified. The semi-dwarf varieties that did not change their plant heights under i and 12hrs conditions were Hira, Yecora Resel, Sava, Sturdy, Saric 70, Sekidorisai 66etc. 4. Varietal difference of culm elongation was noticed between 8hrs and 12hrs daylength condition. On the basis of the evidences obtained from this experiment, it may be concluded that the genetic studies related to culm length should be carried out under the most favorable conditions for culm elongation. 5. Correlation coefficients estimated between culm length and heading or maturity were negative but insignificant, but their correlations were highly significant between photo treatments. 6. Culm length of F_1 was intermediate to the range of F_2 population which seems to be distributed normally. In this regard the gene involved with culm length seemingly inherit additively. Statistical analysis for the involved genes for culm length suggested 2 genes for the semidwarf variety Robin #2.

Vertically oriented epitaxial germanium nanowires on silicon substrates using thin germanium buffer layers

Jung, Jae Hun,Yoon, Hyun Sik,Kim, Yu Lee,Song, Man Suk,Kim, Yong,Chen, Zhi Gang,Zou, Jin,Choi, Duk Yong,Kang, Jung Hyun,Joyce, Hannah J,Gao, Qiang,Hoe Tan, H,Jagadish, Chennupati IOP Pub 2010 Nanotechnology Vol.21 No.29

<P>We demonstrate a method to realize vertically oriented Ge nanowires on Si(111) substrates. Ge nanowires were grown by chemical vapor deposition using Au nanoparticles to seed nanowire growth via a vapor–liquid–solid growth mechanism. Rapid oxidation of Si during Au nanoparticle application inhibits the growth of vertically oriented Ge nanowires directly on Si. The present method employs thin Ge buffer layers grown at low temperature less than 600 °C to circumvent the oxidation problem. By using a thin Ge buffer layer with root-mean-square roughness of ∼ 2 nm, the yield of vertically oriented Ge nanowires is as high as 96.3%. This yield is comparable to that of homoepitaxial Ge nanowires. Furthermore, branched Ge nanowires could be successfully grown on these vertically oriented Ge nanowires by a secondary seeding technique. Since the buffer layers are grown under moderate conditions without any high temperature processing steps, this method has a wide process window highly suitable for Si-based microelectronics. </P>

Lead-Free NaNbO₃ Nanowires for a High Output Piezoelectric Nanogenerator

Jung, Jong Hoon,Lee, Minbaek,Hong, Jung-Il,Ding, Yong,Chen, Chih-Yen,Chou, Li-Jen,Wang, Zhong Lin American Chemical Society 2011 ACS NANO Vol.5 No.12

<P>Perovskite ferroelectric nanowires have rarely been used for the conversion of tiny mechanical vibrations into electricity, in spite of their large piezoelectricity. Here we present a lead-free NaNbO<SUB>3</SUB> nanowire-based piezoelectric device as a high output and cost-effective flexible nanogenerator. The device consists of a NaNbO<SUB>3</SUB> nanowire–poly(dimethylsiloxane) (PDMS) polymer composite and Au/Cr-coated polymer films. High-quality NaNbO<SUB>3</SUB> nanowires can be grown by hydrothermal method at low temperature and can be poled by an electric field at room temperature. The NaNbO<SUB>3</SUB> nanowire–PDMS polymer composite device shows an output voltage of 3.2 V and output current of 72 nA (current density of 16 nA/cm<SUP>2</SUP>) under a compressive strain of 0.23%. These results imply that NaNbO<SUB>3</SUB> nanowires should be quite useful for large-scale lead-free piezoelectric nanogenerator applications.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2011/ancac3.2011.5.issue-12/nn2039033/production/images/medium/nn-2011-039033_0004.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn2039033'>ACS Electronic Supporting Info</A></P>

SIMULATION OF A BUBBLING FLUIDIZED BED BIOMASS GASIFIER USING ASPEN PLUS

Jung-Chin TSAI,Chen-Yaw CHIU,Chih-Shen CHEN 한국신재생에너지학회 2012 AFORE Vol.2012 No.-

Digital Transformation, Manipulation of Asset Evaluation and M&A Performance: Discussion on the Intermediary Effect of Internal Control

Chen Chen,Hee-Jung Lee,Nan Hui,Xue-Hua Qian 강원대학교 경영경제연구소 2023 Asia-Pacific Journal of Business Vol.14 No.1

Purpose - The purpose of this study was to examine the internal relevance between digital transformation, manipulation of asset evaluation and corporate M&A performance and further explores the impact path of manipulation of asset valuation on corporate M&A performance. Design/methodology/approach - This study based on the financial data of A-share listed companies in Shanghai and Shenzhen Stock Exchanges from 2013 to 2021. Findings - First, manipulation of asset evaluation is negatively correlated with M&A performance. Second, Digital transformation significantly weakens the negative correlation between manipulation of asset evaluation and corporate M&A performance. Third, The effectiveness of internal control plays a partially intermediary role in the process of manipulation of asset evaluation affecting M&A performance. Research implications or Originality - Enriching the existing literature on the subject, the study can also provide useful reference for improving the performance of corporate mergers and acquisitions, regulating asset valuation, promoting the digital transformation of enterprises and improving internal control mechanisms, with both theoretical and practical implications.

Dynamics of dissolved organic matter in riverine sediments affected by weir impoundments: Production, benthic flux, and environmental implications

Chen, Meilian,Kim, Sung-Han,Jung, Heon-Jae,Hyun, Jung-Ho,Choi, Jung Hyun,Lee, Hyo-Jin,Huh, In-Ae,Hur, Jin Elsevier 2017 Water research Vol.121 No.-

<P><B>Abstract</B></P> <P>In order to understand the characteristics and dynamics of dissolved organic matter (DOM) in the sediment of rivers affected by impoundments, we examined the vertical profiles and the benthic fluxes of DOM in four different core sediments located at upstream sites of weirs in major rivers of South Korea. In three out of four sites, exponential accumulation of dissolved organic carbon (DOC) with depth was observed with the signature of seasonal variability. Except for the site displaying a below-detection limit of Fe(II), the general accumulation trends of DOC with depth was concurrent with the increases of Fe(II) and NH<SUB>4</SUB> <SUP>+</SUP> and the decrease of PO<SUB>4</SUB> <SUP>3-</SUP>, signifying a close linkage of the DOM dynamics with anaerobic respiration via iron reduction, an important early diagenesis pathway. The estimated benthic fluxes from the cores revealed that the sediments likely serve as DOC, chromophoric DOM (CDOM), and fluorescent DOM (FDOM) sources to the overlying water. The benthic effluxes based on DOC were comparable to the ranges previously reported in lake and coastal areas, and those of CDOM and FDOM showed even higher levels. These findings imply that impoundment-affected river systems would change the DOM composition of the overlying water, ultimately influencing the subsequent water treatment processes such as disinfection byproducts production and membrane fouling. A simple mass balance model indicated that the impoundment-affected river sediments may operate as a net carbon sink in the environments due to a greater extent of sedimentation compared to the estimated benthic efflux and sediment biological respiration.</P> <P><B>Highlights</B></P> <P> <UL> <LI> DOC is exponentially accumulated with depth in most impoundment-affected sites. </LI> <LI> Positive correlation of DOC with Fe(II) reveals DOM production via iron reduction. </LI> <LI> Sediments serve as sources of DOC, CDOM, and FDOM to overlying water. </LI> </UL> </P>

Colorimetric and fluorometric detection of cationic surfactants based on conjugated polydiacetylene supramolecules

Chen, Xiaoqiang,Lee, Jung,Jou, Min Jung,Kim, Jong-Man,Yoon, Juyoung Royal Society of Chemistry 2009 Chemical communications Vol.2009 No.23

<P>The polydiacetylenes derived from a hydroxybenzaldehyde substituted diacetylene monomer display a unique colorimetric change (blue to red) and large fluorescent enhancement in the presence of cetyl trimethylammonium salt.</P> <P>Graphic Abstract</P><P>The PDAs derived from a hydroxybenzaldehyde substituted diacetylene monomer display a unique colorimetric change (blue to red) and large fluorescent enhancement in the presence of cationic surfactants (CS). <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=b904542b'> </P>

Process Systems Engineering, Process Safety, Transport Phenomena : Multiloop PID Controller Design using Partial Least Squares Decoupling Structure

( Jung Hui Chen ),( Yi Chun Cheng ),( Yue Zhi Yea ) 한국화학공학회 2005 Korean Journal of Chemical Engineering Vol.22 No.2