• Title/Summary/Keyword: center symmetry

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Exploration of structural, thermal and spectroscopic properties of self-activated sulfate Eu2(SO4)3 with isolated SO4 groups

  • Denisenko, Yu.G.;Aleksandrovsky, A.S.;Atuchin, V.V.;Krylov, A.S.;Molokeev, M.S.;Oreshonkov, A.S.;Shestakov, N.P.;Andreev, O.V.
    • Journal of Industrial and Engineering Chemistry
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    • v.68
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    • pp.109-116
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    • 2018
  • $Eu_2(SO_4)_3$ was synthesized by chemical precipitation method and the crystal structure was determined by Rietveld analysis. The compound crystallizes in monoclinic space group C2/c. In the air environment, $Eu_2(SO_4)_3$ is stable up to $670^{\circ}C$. The sample of $Eu_2(SO_4)_3$ was examined by Raman, Fourier-transform infrared absorption and luminescence spectroscopy methods. The low site symmetry of $SO_4$ tetrahedra results in the appearance of the IR inactive ${\nu}_1$ mode around $1000cm^{-1}$ and ${\nu}_2$ modes below $500cm^{-1}$. The band intensities redistribution in the luminescent spectra of $Eu^{3+}$ ions is analyzed in terms of the peculiarities of its local environment.

Immediate Breast Reconstruction after Resection of Cavernous Hemangioma (유방의 해면양 혈관종의 절제 후 보형물을 이용한 즉시 재건)

  • Kim, Eun Key;Lee, Taik Jong
    • Archives of Plastic Surgery
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    • v.33 no.5
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    • pp.577-580
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    • 2006
  • Purpose: Hemangioma of the breast is an infrequent finding and usually encountered incidentally when checking for other disease. Most of hemangiomas of the breast are asymptomatic, not palpable perilobular type. Cavernous hemangioma of the breast is rare and only a few reports about this type of lesion are present. No example has been reported about reconstruction of the breast after resection of large cavernous hemangioma. Methods: We report here a case of immediate breast reconstruction using a Becker implant after subcutaneous mastectomy for a large cavernous hemangioma involving almost entire breast. Results: Symmetry is well maintained after 3 years without deformity or recurrence. Conclusion: The clinical prognosis of breast cavernous hemangioma is good after total excision and reconstruction.

Design of IIR Notch Filter for Removal of Baseline wander and Power Line Interference from ECG Signal

  • Chivapreecha, Sorawat;Dejhan, Kobchai;Yimman, Surapan
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.848-851
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    • 2005
  • This paper proposes a design of IIR notch filter with modified pole placements. The pole angle is derived from quadratic programming to find the appropriate pole position on the unit circle in z-plane in order to achieve the symmetry of the amplitude response. The simulation results are shown when compared with the conventional design technique. Moreover, it uses the TMS320C31 DSP chip for hardware implementation. Finally, the hardware implementation can be applied to removal of ECG baseline wander and elimination of AC power line interference in ECG signal.

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Effective adjacent baggage split method of Baggage Position Control System to prevent double loading of baggage

  • Song, Jae-Won;Kim, Dong-Chul
    • Journal of the Korea Society of Computer and Information
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    • v.23 no.3
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    • pp.33-40
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    • 2018
  • In this paper, we propose a method to effectively split the adjacent baggage that is moving on high speed conveyor of airport. The proposed method calculate the Angle Histogram(AH) that inspects background pixels within radius r based on the center point of the adjacent baggage. After that, the adjacent baggage is segmented by finding split angles at the AH. We also improved the split quality of adjoining baggage by repeatedly correcting the center point to correctly split adjacent baggage of asymmetric size. And the calculation time of AH is reduced about 1/3 by using the symmetry property of the circle. Experiments have shown that 93% of all adjacent baggage images are correctly segmented and the proposed method is effective.

Crystal and Molecular Structure of Hexaimidazolidone Chromium(III) Nitrate, $[Cr(OC_3H_6N_2)_6](NO_3)_3\cdot4H_2O$ (Hexaimidazolidone Chromium(III) Nitrate, $[Cr(OC_3H_6N_2)_6](NO_3)_3.4H_2O$의 결정 및 분자 구조)

  • Suh, Jung-Sun;Lee, Kyu-Wang;Suh, Il-Hwan
    • Korean Journal of Crystallography
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    • v.11 no.2
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    • pp.71-74
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    • 2000
  • The title compound, [Cr(OC3H6N2)6](NO3)3·4H2O, was crystallized in the centrosymmetric space group P with two half molecules in an asymmetric unit, and the two complete molecules are generated by inversion symmetry located at Cr atoms. Therefore, the Cr atoms are coordinated to six imidazolidone ligands through the oxygen atoms, and both CrO6 units have a slightly distorted octahedral geometry.

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Magnetism in α-RuCl3 : Dependence on Coulomb Interaction and Hund's Coupling

  • Gong, Hoshin;Kim, Kyoo;Ji, Sungdae;Kim, Bongjae;Min, B.I.
    • Journal of the Korean Physical Society
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    • v.73 no.11
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    • pp.1691-1697
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    • 2018
  • Employing the density functional theory, we have investigated the roles of Coulomb and Hund's interactions in the electronic and magnetic properties of newly discovered ${\alpha}-RuCl_3$ having the $R{\overline{3}}$ symmetry, which is in close proximity of the Kitaev system. We show that both the size and the direction of local magnetic moment are highly dependent on Coulomb and Hund's interactions, and the spin and orbital parts show different behaviors. The validity of the so-called $j^{eff}$ picture is accessed upon interaction parameters, and the explicit roles of Hund's interaction in the local electronic structures and magnetic properties are discussed.

A Comparative Study of Gait Characteristics between Single Axis Foot and Energy Storing Foot for Sports in Trans-tibial Amputee (하퇴절단자용 단축식 발과 스포츠용 에너지 저장형 발 보행 특성 비교연구)

  • Chang, Yun-Hee;Bae, Tae-Soo;Kim, Shin-Ki;Mun, Mu-Seong
    • Journal of the Korean Society for Precision Engineering
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    • v.26 no.2
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    • pp.126-132
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    • 2009
  • This study examined the differences in spatio-temporal parameters, joint angle, ground reaction force (GRF), and joint power according to the changes of gait speed for trans-tibial amputees to investigate the features of the energy-storing foot for sports. The subjects walked at normal speed and at fast speed, wearing a single-axis type foot (Korec) and an energy-storing foot for sports (Renegade) respectively. The results showed that Renegade yielded faster gait speed as well as more symmetric gait pattern, compared to Korec. However, as gait speed was increased, there was no significant difference in kinematics, ground reaction force, and joint power between two artificial foots. This was similar to the results from previous studies regarding the energy-storing foot, where the walking velocity and gait symmetry have been improved. Nevertheless, the result of this study differed from the previous ones which reported that joint angle, joint power, and GRF increased as the gait speed increased except spatio-temporal parameters.

Electron beam scattering device for FLASH preclinical studies with 6-MeV LINAC

  • Jeong, Dong Hyeok;Lee, Manwoo;Lim, Heuijin;Kang, Sang Koo;Lee, Sang Jin;Kim, Hee Chang;Lee, Kyohyun;Kim, Seung Heon;Lee, Dong Eun;Jang, Kyoung Won
    • Nuclear Engineering and Technology
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    • v.53 no.4
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    • pp.1289-1296
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    • 2021
  • In this study, an electron-scattering device was fabricated to practically use the ultra-high dose rate electron beams for the FLASH preclinical research in Dongnam Institute of Radiological and Medical Sciences. The Dongnam Institute of Radiological and Medical Sciences has been involved in the investigation of linear accelerators for preclinical research and has recently implemented FLASH electron beams. To determine the geometry of the scattering device for the FLASH preclinical research with a 6-MeV linear accelerator, the Monte Carlo N-particle transport code was exploited. By employing the fabricated scattering device, the off-axis and depth dose distributions were measured with radiochromic films. The generated mean energy of electron beams via the scattering device was 4.3 MeV, and the symmetry and flatness of the off-axis dose distribution were 0.11% and 2.33%, respectively. Finally, the doses per pulse were obtained as a function of the source to surface distance (SSD); the measured dose per pulse varied from 4.0 to 0.2 Gy/pulse at an SSD range of 20-90 cm. At an SSD of 30 cm with a 100-Hz repetition rate, the dose rate was 180 Gy/s, which is sufficient for the preclinical FLASH studies.

Determination of Reorganization Energy from the Temperature Dependence of Electron Transfer Rate Constant for Hydroquinone-tethered Self-assembled Monolayers (SAMs)

  • Park, Won-choul;Hong, Hun-Gi
    • Bulletin of the Korean Chemical Society
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    • v.27 no.3
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    • pp.381-385
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    • 2006
  • The temperature dependence on the electron transfer rate constant $(k_{app})$ for hydroquinone redox center in $H_2Q(CH_2)_n$SH-SAMs (n = 1, 4, 6, 8, 10, and 12) on gold electrode was investigated to obtain reorganization energy $(\lambda)$ using Laviron’s formalism and Arrhenius plot of ln $[k_{app}/T^{1/2}]$ vs. T^{-1} based on the Marcus densityof-states model. All the symmetry factors measured for the SAMs were relatively close to unity and rarely varied to temperature change as expected. The electron tunneling constant $(\beta)$ determined from the dependence of the $k_{app}$ on the distance between the redox center and the electrode surface gives almost the same $\beta$ values which are quite insensitive to temperature change. Good linear relationship of Arrhenius plot for all $H_2Q(CH_2)_n$SH-SAMs on gold electrode was obtained in the temperature range from 273 to 328 K. The slopes n Arrhenius plot deduced that $\lambda$ of hydroquinone moiety is ca. 1.3-1.4 eV irrespectively of alkyl chain length of the electroactive SAM.

Stereoselective attachment of S-Proline on Ge(100)

  • Youn, Young-Sang;Kim, Ki-Jeong;Kim, Bong-Soo;Lee, Hang-Il;Kim, Se-Hun
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.02a
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    • pp.367-367
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    • 2010
  • The adsorption configurations of S-proline on Ge(100) were studied using scanning tunneling microscopy (STM), density functional theory (DFT) calculations, and high-resolution core-level photoemission spectroscopy (HRCLPES). We identified three adsorption structures of S-proline on Ge(100) through analysis of the STM images, DFT calculations, and HRCLPES results: (i) an 'intrarow O - H dissociated and N dative bonded structure', (ii) an 'O - H dissociation structure', and (iii) an 'N dative bonded structure'. Moreover, because adsorption through the N atom of S-proline produces a new chiral center due to symmetry reduction by N dative bonding, the adsorption configurations have either (R,S) or (S,S) chirality, yielding an (R,S)-'intrarow O - H dissociated and N dative bonded structure' and an (R,S)-'N dative bonded structure', with a preference for reaction at the Re face. This work presents a novel method for generating stereoselective attachment using S-proline molecules adsorbed onto a Ge(100) surface.

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