RISS 학술연구정보서비스

검색
다국어 입력

http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.

변환된 중국어를 복사하여 사용하시면 됩니다.

예시)
  • 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
  • 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
닫기
    인기검색어 순위 펼치기

    RISS 인기검색어

      검색결과 좁혀 보기

      선택해제
      • 좁혀본 항목 보기순서

        • 원문유무
        • 원문제공처
        • 등재정보
        • 학술지명
          펼치기
        • 주제분류
        • 발행연도
          펼치기
        • 작성언어
        • 저자
          펼치기

      오늘 본 자료

      • 오늘 본 자료가 없습니다.
      더보기
      • 무료
      • 기관 내 무료
      • 유료
      • KCI등재

        Static assessment of quadratic hybrid plane stress element using non-conforming displacement modes and modified shape functions

        Kyoung-Sik Chun,Samuel Kinde Kassegne,박원태 국제구조공학회 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.29 No.6

        In this paper, we present a quadratic element model based on non-conforming displacement modes and modified shape functions. This new and refined 8-node hybrid stress plane element consists of two additional non-conforming modes that are added to the translational degree of freedom to improve the behavior of a membrane component. Further, the modification of the shape functions through quadratic polynomials in x-y coordinates enables retaining reasonable accuracy even when the element becomes considerably distorted. To establish its accuracy and efficiency, the element is compared with existing elements and - over a wide range of mesh distortions – it is demonstrated to be exceptionally accurate in predicting displacements and stresses.

      • Registration accuracy enhancement of a surgical navigation system for anterior cruciate ligament reconstruction: A phantom and cadaveric study

        Kim, Youngjun,Lee, Byung Hoon,Mekuria, Kinde,Cho, Hyunchul,Park, Sehyung,Wang, Joon Ho,Lee, Deukhee Elsevier 2017 The knee Vol.24 No.2

        <P><B>Abstract</B></P> <P><B>Background</B></P> <P>Recently, surgical navigation systems have been widely used to improve the results of various orthopaedic surgeries. However, surgical navigation has not been successful in anterior cruciate ligament reconstruction, owing to its inaccuracy and inconvenience. This study investigated the registration of preoperative and intraoperative data, which are the key components in improving accuracy of the navigation system.</P> <P><B>Methods</B></P> <P>An accurate registration method was proposed using new optical tracking markers and landmark retake. A surgical planning and navigation system for anterior cruciate ligament reconstruction was developed and implemented. The accuracy of the proposed system has been evaluated using phantoms and eight cadaveric knees. The present study investigated only the registration accuracy excluding the errors of optical tracking hardware and surgeon.</P> <P><B>Results</B></P> <P>The target registration errors of femoral tunnelling for anterior cruciate ligament reconstruction in phantoms were found to be 0.24±0.03mm and 0.19±0.10° for the tunnel entry position and tunnel direction, respectively. The target registration errors measured using cadavers were 0.9mm and 1.94°, respectively.</P> <P><B>Conclusions</B></P> <P>The preclinical experimental results showed that the proposed methods enhanced the registration accuracy of the developed system. As the system becomes more accurate, surgeons could more precisely position and orient the femoral and tibial tunnels to their original anatomical locations.</P>

      • SCIESCOPUS

        Static assessment of quadratic hybrid plane stress element using non-conforming displacement modes and modified shape functions

        Chun, Kyoung-Sik,Kassegne, Samuel Kinde,Park, Won-Tae Techno-Press 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.29 No.6

        In this paper, we present a quadratic element model based on non-conforming displacement modes and modified shape functions. This new and refined 8-node hybrid stress plane element consists of two additional non-conforming modes that are added to the translational degree of freedom to improve the behavior of a membrane component. Further, the modification of the shape functions through quadratic polynomials in x-y coordinates enables retaining reasonable accuracy even when the element becomes considerably distorted. To establish its accuracy and efficiency, the element is compared with existing elements and - over a wide range of mesh distortions - it is demonstrated to be exceptionally accurate in predicting displacements and stresses.

      • SCISCIESCOPUS
      • Determination of elemental compositions by gas chromatography/time-of-flight mass spectrometry using chemical and electron ionization

        Abate, Salvatore,Ahn, Yun Gyong,Kind, Tobias,Cataldi, Tommaso R. I.,Fiehn, Oliver John Wiley Sons, Ltd. 2010 Rapid communications in mass spectrometry Vol.24 No.8

        <P>Many metabolomic applications use gas chromatography/mass spectrometry (GC/MS) under standard 70 eV electron ionization (EI) parameters. However, the abundance of molecular ions is often extremely low, impeding the calculation of elemental compositions for the identification of unknown compounds. On changing the beam-steering voltage of the ion source, the relative abundances of molecular ions at 70 eV EI were increased up to ten-fold for alkanes, fatty acid methyl esters and trimethylsilylated metabolites, concomitant with 2-fold absolute increases in ion intensities. We have compared the abundance, mass accuracy and isotope ratio accuracy of molecular species in EI with those in chemical ionization (CI) with methane as reagent gas under high-mass tuning. Thirty-three peaks of a diverse set of trimethylsilylated metabolites were analyzed in triplicate, resulting in 342 ion species ([M+H]<SUP>+</SUP>, [M–CH<SUB>3</SUB>]<SUP>+</SUP> for CI and [M]<SUP>+.</SUP>, [M–CH<SUB>3</SUB>]<SUP>+.</SUP> for EI). On average, CI yielded 8-fold more intense molecular species than EI. Using internal recalibration, average mass errors of 1.8 ± 1.6 mm/z units and isotope ratio errors of 2.3 ± 2.0% (A+1/A ratio) and 1.7 ± 1.8% (A+2/A ratio) were obtained. When constraining lists of calculated elemental compositions by chemical and heuristic rules using the Seven Golden Rules algorithm and PubChem queries, the correct formula was retrieved as top hit in 60% of the cases and within the top-3 hits in 80% of the cases. Copyright © 2010 John Wiley & Sons, Ltd.</P>

      • KCI등재

        Broccoli (Brassica oleracea) Reduces Oxidative Damage to Pancreatic Tissue and Combats Hyperglycaemia in Diabetic Rats

        Sithara Suresh,Mostafa Ibrahim Waly,Mohammad Shafiur Rahman,Nejib Guizani,Mohamed Abdullah Badar Al-Kind,Halima Khalfan Ahmed Al-Issaei,Sultan Nasser Mohd Al-Maskari,Bader Rashid Said Al-Ruqaishi,Ahme 한국식품영양과학회 2017 Preventive Nutrition and Food Science Vol.22 No.4

        Oxidative stress plays a pivotal role in the development of diabetes and hyperglycaemia. The protective effects of natural extracts against diabetes are mainly dependent on their antioxidant and hypoglycaemic properties. Broccoli (Brassica oleracea) exerts beneficial health effects in several diseases including diabetes; however, the mechanism has not been elucidated yet. The present study was carried out to evaluate the potential hypoglycaemic and antioxidant properties of aqueous broccoli extracts (BEs) in diabetic rats. Streptozotocin (STZ) drug was used as a diabetogenic agent in a single intraperitoneal injection dose of 50 mg/kg body weight. The blood glucose level for each rat was measured twice a week. After 8 weeks, all animals were fasted overnight and sacrificed; pancreatic tissues were homogenized and used for measuring oxidative DNA damage, biochemical assessment of glutathione (GSH), and total antioxidant capacity (TAC) as well as histopathological examination for pancreatic tissues was examined. Diabetic rats showed significantly higher levels of DNA damage, GSH depletion, and impaired TAC levels in comparison to non-diabetics (P<0.05). The treatment of diabetic rats with BE significantly reduced DNA damage and conserved GSH and TAC values (P<0.01). BE attenuated pancreatic histopathological changes in diabetic rats. The results of this study indicated that BE reduced the STZ mediated hyperglycaemia and the STZ-induced oxidative injury to pancreas tissue. The used in vivo model confirmed the efficacy of BE as an anti-diabetic herbal medicine and provided insights into the capacity of BE to be used for phytoremediation purposes for human type 2 diabetes.

      • SCISCIESCOPUS

        Spectroscopic needs for imaging dark energy experiments

        Newman, J.A.,Abate, A.,Abdalla, F.B.,Allam, S.,Allen, S.W.,Ansari, R.,Bailey, S.,Barkhouse, W.A.,Beers, T.C.,Blanton, M.R.,Brodwin, M.,Brownstein, J.R.,Brunner, R.J.,Carrasco Kind, M.,Cervantes-Cota, North-Holland 2015 Astroparticle physics Vol.63 No.-

        Ongoing and near-future imaging-based dark energy experiments are critically dependent upon photometric redshifts (a.k.a. photo-z's): i.e., estimates of the redshifts of objects based only on flux information obtained through broad filters. Higher-quality, lower-scatter photo-z's will result in smaller random errors on cosmological parameters; while systematic errors in photometric redshift estimates, if not constrained, may dominate all other uncertainties from these experiments. The desired optimization and calibration is dependent upon spectroscopic measurements for secure redshift information; this is the key application of galaxy spectroscopy for imaging-based dark energy experiments. Hence, to achieve their full potential, imaging-based experiments will require large sets of objects with spectroscopically-determined redshifts, for two purposes:*Training: Objects with known redshift are needed to map out the relationship between object color and z (or, equivalently, to determine empirically-calibrated templates describing the rest-frame spectra of the full range of galaxies, which may be used to predict the color-z relation). The ultimate goal of training is to minimize each moment of the distribution of differences between photometric redshift estimates and the true redshifts of objects, making the relationship between them as tight as possible. The larger and more complete our ''training set'' of spectroscopic redshifts is, the smaller the RMS photo-z errors should be, increasing the constraining power of imaging experiments. Requirements: Spectroscopic redshift measurements for ~30,000 objects over >~15 widely-separated regions, each at least ~20arcmin in diameter, and reaching the faintest objects used in a given experiment, will likely be necessary if photometric redshifts are to be trained and calibrated with conventional techniques. Larger, more complete samples (i.e., with longer exposure times) can improve photo-z algorithms and reduce scatter further, enhancing the science return from planned experiments greatly (increasing the Dark Energy Task Force figure of merit by up to ~50%). Options: This spectroscopy will most efficiently be done by covering as much of the optical and near-infrared spectrum as possible at modestly high spectral resolution (λ/Δλ>~3000), while maximizing the telescope collecting area, field of view on the sky, and multiplexing of simultaneous spectra. The most efficient instrument for this would likely be either the proposed GMACS/MANIFEST spectrograph for the Giant Magellan Telescope or the OPTIMOS spectrograph for the European Extremely Large Telescope, depending on actual properties when built. The PFS spectrograph at Subaru would be next best and available considerably earlier, c. 2018; the proposed ngCFHT and SSST telescopes would have similar capabilities but start later. Other key options, in order of increasing total time required, are the WFOS spectrograph at TMT, MOONS at the VLT, and DESI at the Mayall 4m telescope (or the similar 4MOST and WEAVE projects); of these, only DESI, MOONS, and PFS are expected to be available before 2020. Table 2-3 of this white paper summarizes the observation time required at each facility for strawman training samples. To attain secure redshift measurements for a high fraction of targeted objects and cover the full redshift span of future experiments, additional near-infrared spectroscopy will also be required; this is best done from space, particularly with WFIRST-2.4 and JWST. Calibration: The first several moments of redshift distributions (the mean, RMS redshift dispersion, etc.), must be known to high accuracy for cosmological constraints not to be systematics-dominated (equivalently, the moments of the distribution of differences between photometric and true redshifts could be determined instead). The ultimate goal of calibration is to characterize these moments for every subsample used in analyses - i.e., to minimi

      연관 검색어 추천

      이 검색어로 많이 본 자료

      활용도 높은 자료

      해외이동버튼