• 제목/요약/키워드: non-symmetry

검색결과 162건 처리시간 0.031초

The Crystal Structure of Fenbufen, 3-(4-biphenylylcarbonyl)propionic acid ($C_{16}H_{14}O_3$), A Non-steroidal Antiinflammatory Agent

  • Kim, Yang-Bae;Park, Il-Yeong;Park, Yang-Hwan
    • Archives of Pharmacal Research
    • /
    • 제11권2호
    • /
    • pp.127-133
    • /
    • 1988
  • The crystal structure of fenbufen was determined by X-ray diffraction techniuques. The compound was recrystallized in orthorhombic crystal system, space group $Pca2_1$ a = 31. 918(10), b = 5.550 (2), c = 15.078 (9) ${\AA}, D_m$= $1.26, {\D_x$= 1.264 g/$\textrm{cm}^3$, and Z = 8. The structure was solved by direct methods and refined by least squares procedure to the final R value of 0.051 for 1780 independent reflections. Two molecules in the asymmetric unit are related by a pseudo center of symmetry and dimerized via O-H...O hydrogen bonds. The carbonyl group attached to the phenyl ring is nearly coplanar to the ring. In the crystal the molecules are arranged in paralle stacks in the a direction.

  • PDF

Fracture analysis of inhomogeneous arch with two longitudinal cracks under non-linear creep

  • Victor I. Rizov;Holm Altenbach
    • Advances in materials Research
    • /
    • 제12권1호
    • /
    • pp.15-29
    • /
    • 2023
  • In this paper, fracture analysis of a continuously inhomogeneous arch structure with two longitudinal cracks is developed in terms of the time-dependent strain energy release rate. The arch under consideration exhibits non-linear creep behavior. The cross-section of the arch is a rectangle. The material is continuously inhomogeneous along the thickness of the cross-section. The arch is loaded by two bending moments applied at its end sections. The mechanical behavior of the material is described by using a non-linear stress-strain-time relationship. The two longitudinal cracks are located symmetrically with respect to the mid-span of the arch. Due to the symmetry, only half of the arch is considered. Time-dependent solutions to strain energy release rate are obtained by analyzing the balance of the energy. For verification, time-dependent solutions to the strain energy release rate are derived also by considering the time-dependent complementary strain energy. The evolution of the strain energy release rate with the time is analyzed. The effects of material inhomogeneity, locations of the two cracks along the thickness of the arch and the magnitude of the external loading on the time-dependent strain energy release rate are evaluated.

이차 구순비 변형 환자에서 Spacer Graft를 이용한 콧방울뒤당김(retracted ala)의 교정 (Correction of Retracted Ala Using Spacer Graft in Secondary Cleft Lip and Nose Deformity)

  • 한규석;최현곤;신동혁;김순흠;황은아;엄기일
    • Archives of Plastic Surgery
    • /
    • 제38권4호
    • /
    • pp.376-382
    • /
    • 2011
  • Purpose: In patients with unilateral cleft lip and nose deformity, alar retraction is commonly seen on the non-cleft side after cleft side is corrected. Spacer graft was used to drag down the inferior border of the alar cartilage of the non-cleft side so as to match the cleft side. By performing spacer graft and septal extension graft together, symmetry and cosmetic improvements were achieved. Methods: Seven unilateral cleft lip and nose deformity patients underwent surgery for alar retraction correction. The median age was 24 years (ranged from 15 to 34 years), and the median follow-up period was 7.4 months (ranged from 6 to 12 months). The perpendicular length from the longitudinal axis of the nostril to the alar rim, the nasolabial angle and the ala-labial angle were measured in the lateral view photo. The longest perpendicular length from the cephalic border of the alar rim to the parallel line of the alar base was measured in the frontal view photo. Results: Improvement in alar retraction was seen after the surgery. There were no specific complications during the follow-up and the symmetry of both nostrils was satisfactory. No increase in the nasolabial angle or exposure of the nostrils was seen after the tip projection via tip plasty. Conclusion: The fundamental factor in correcting alar retraction with secondary cleft lip and nose deformity is repositioning the alar rim with spacer graft, which seems to be more physiologic than other methods. The method combining spacer graft with septal extension graft will bring symmetry as well as more cosmetic improvement in correction of alar retraction with secondary cleft lip and nose deformity.

Asymmetric flows of non-Newtonian fluids in symmetric stenosed artery

  • Hun Jung;Park, Jong-Wook;Park, Chan-Guk
    • Korea-Australia Rheology Journal
    • /
    • 제16권2호
    • /
    • pp.101-108
    • /
    • 2004
  • The hemodynamics behavior of the blood flow is influenced by the presence of the arterial stenosis. If the stenosis is present in an artery, normal blood flow is disturbed. In the present study, the characteristics of pulsatile flow in the blood vessel with stenosis are investigated by the finite volume method. For the validation of numerical model, the computation results are compared with the experimental ones of Ojha et al. in the case of 45% stenosis with a trapezoidal profile. Comparisons between the measured and the computed velocity profiles are favorable to our solutions. Finally, the effects of stenosis severity and wall shear stress are discussed in the present computational analysis. It can be seen, where the non-dimensional peak velocity is displayed for all the stenosis models at a given severity of stenosis, that it is exponentially increased. Although the stenosis and the boundary conditions are all symmetric, the asymmetric flow can be detected in the more than 57% stenosis. The instability by a three-dimensional symmetry-breaking leads to the asymmetric separation and the intense swirling motion downstream of the stenosis.

Approximate Analysis of MAC Protocol with Multiple Self-tokens in a Slotted Ring

  • Sakuta, Makoto;Sasase, Iwao
    • Journal of Communications and Networks
    • /
    • 제5권3호
    • /
    • pp.249-257
    • /
    • 2003
  • Ring networks are very commonly exploited among local area and metropolitan area networks (LAN/MAN), whereas cells or small fixed-size packets are widely used in synchronized ring networks. In this paper, we present an analytical method for evaluating the delay-throughput performance of a MAC protocol with multiple self-tokens in a slotted ring network under uniform traffic. In our analysis, we introduce the stationary probability, which indicates the number of packets in a node. Also, it is assumed that each node has a sufficiently large amount of self-tokens, and a slotted ring has the symmetry. The analytical results with respect to delay-throughput performance have similar values to computer simulated ones. Furthermore, in order to achieve fair access under non-uniform traffic, we propose an adaptive MAC protocol, where the number of self-tokens in a node dynamically varies, based on the number of packets transmitted within a specified period. In the proposed protocol, when the number of packets transmitted by a node within a specified period is larger than a specified threshold, the node decreases the number of self-tokens in a per-node distributed method. That results in creating free slots in the ring, thus all nodes can obtain an equal opportunity to transmit into the ring. Performance results obtained by computer simulation show that our proposed protocol can maintain throughput fairness under non-uniform traffic.

다운증후군 아동들의 보행 비대칭성 연구 (Gait Asymmetry in Children with Down Syndrome)

  • 임비오;한동기;서정석;은선덕;권영후
    • 한국운동역학회지
    • /
    • 제16권2호
    • /
    • pp.145-151
    • /
    • 2006
  • A large interindividual variability and some abnormally kinematic patterns at the lower extremity were the main features of the gait in children with Down syndrome. The purposes of this study were to investigate the gait asymmetry and biomechanical difference between dominant leg and non dominant leg in children with Down syndrome. Seven boys with Down Syndrome(age: $120{\pm}0.9yrs$, weight $34.4{\pm}8.4kg$, leg length: $68.7{\pm}5.0cm$) participated in this study. A 10.0 m ${\times}$ 1.3 m walkway with a firm dark surface was built and used for data collection. Three-dimensional motion analyses were performed to obtain the joint angles and range of motions. The vertical ground reaction forces(%BW) and impulses($%BW{\cdot}s$) were measured by two force plates embedded in the walkway. Asymmetry indices between the legs were computed for all variables. After decision the dominant leg and the non dominant leg with max hip abduction angle, paired samples t-test was employed for selected kinematic and ground reaction force variables to analyze the differences between the dominant leg and the non dominant leg. The max hip abduction angle during the swing phase showed most asymmetry, while the knee flexion angle at initial contact showed most symmetry in walking and running. The dominant leg showed more excessive abduction of hip in the swing phase and more flat-footed contact than the non dominant leg. Vertical peak force in running showed more larger than those of in walking, however, vertical impulse showed more small than walking due to decrease of support time. In conclusion, the foot of dominant leg contact more carefully than those of non dominant leg. And also, there are no significant difference between the dominant leg and the non dominant leg in kinematic variables and ground reaction force due to large interindividual variability.

Eu3+와 Tb3+ 활성제 이온이 SrSnO3 형광체의 특성에 미치는 영향 (Effects of Eu3+ and Tb3+ Activator Ions on the Properties of SrSnO3 Phosphors)

  • 김정대;조신호
    • 한국재료학회지
    • /
    • 제24권9호
    • /
    • pp.469-473
    • /
    • 2014
  • $SrSnO_3$ phosphor powders were synthesized with two different contents of activator ions $Eu^{3+}$ and $Tb^{3+}$ using the solid-state reaction method. The structural, morphological, and optical properties of the phosphors were investigated using X-ray diffractometry, field-emission scanning electron microscopy, and fluorescence spectrophotometry, respectively. All the phosphors showed a cubic structure, irrespective of the type and the content ratio of activator ions. For $Eu^{3+}$-doped $SrSnO_3$ phosphors, the intensity of the 620 nm red emission spectrum resulting from the $^5D_0{\rightarrow}^7F_2$ transition of $Eu^{3+}$ was stronger than that of the 595 nm orange emission signal due to the $^5D_0{\rightarrow}^7F_1$ transition in the range 0.01-0.05 mol of $Eu^{3+}$, but the ratio of the intensity was reversed in the range 0.10-0.20 mol of $Eu^{3+}$. The variation in the emission intensity indicates that the site symmetry of the $Eu^{3+}$ ions around the host crystal was changed from non-inversion symmetry to inversion. For the $Tb^{3+}$-doped $SrSnO_3$ phosphors under excitation at 281 nm, one strong green emission band at 550 nm and several weak bands were observed. These results suggest that the optimum red and green emission signals can be realized when the activator ion content for $Eu^{3+}$- or $Tb^{3+}$-doped $SrSnO_3$ phosphors is 0.20 mol and 0.15 mol, respectively.

BiNbO4:RE3+ (RE = Dy, Eu, Sm, Tb) 형광체의 광학 특성 (Photoluminescence Properties of BiNbO4:RE3+ (RE = Dy, Eu, Sm, Tb) Phosphors)

  • 이상운;조신호
    • 한국표면공학회지
    • /
    • 제50권3호
    • /
    • pp.206-211
    • /
    • 2017
  • $BiNbO_4:RE^{3+}$ (RE = Dy, Eu, Sm, Tb) phosphors were prepared by solid-state reaction at $1100^{\circ}C$ and their structural, photoluminescent, and morphological properties were investigated. XRD patterns exhibited that all the synthesized phosphors exhibited a triclinic system with a dominant (210) diffraction peak, irrespective of the type of activator ions. The surface morphologies of rare-earth-ion-doped $BiNbO_4$ phosphors were found to depend strongly on the type of activator ions. The $Eu^{3+}$ and $Dy^{3+}$ doped $BiNbO_4$ phosphors revealed a strong red (613 nm) emission resulting from the $^5D_0{\rightarrow}^7F_2$ transition of $Eu^{3+}$ and a dominant yellow (575 nm) emission originating from the $^4F_{9/2}{\rightarrow}^6H_{13/2}$ transition of $Dy^{3+}$ respectively, which were the electric dipole transitions, indicating that the activator ions occupy sites of non-inversion symmetry in the $BiNbO_4$ phosphor. The main reddish-orange emission spectra of $Sm^{3+}$-doped $BiNbO_4$ phosphors were due to the $^4G_{5/2}{\rightarrow}^6H_{7/2}$ (607 nm) magnetic dipole transition, indicating that the $Sm^{3+}$ ions were located at inversion symmetry sites in the $BiNbO_4$ host lattice. As for $Tb^{3+}$-doped phosphors, green emission was obtained under excitation at 353 nm and its CIE chromaticity coordinates were (0.274, 0.376). These results suggest that multicolor emission can be achieved by changing the type of activator ions incorporated into the $BiNbO_4$ host crystal.

1950년대 건립된 강원지역 성당건축의 건축적 특성 (Architectural Characteristics of Catholic Churches built in 1950s in Gangwon Province)

  • 서성남;최장순
    • 한국농촌건축학회논문집
    • /
    • 제20권4호
    • /
    • pp.65-75
    • /
    • 2018
  • This thesis attempts to investigate and analyse the architectural characteristics of catholic churches in Gangwon province built in the 1950s. Catholic churches built at that time in Korea had many similarities basically since they were supported by UN forces after the Korean War and were established by priests connected to the Missionary Society of St. Columban. The results of study are as follows. In location, Except one catholic church, the catholic churches preferred low and gentle hill. In layout axis, catholic churches at Youngseo area preferred the north-south layout axis, whereas those at Youngdong favor the east-west layout axis. In approach, most of catholic churches around the Youngseo and Youngdong areas preferred entering the front entrance with a bell tower, whereas three of them at Youngdong did entering the front entrance with a bell tower around the rear corner. In floor plan, catholic churches at Youngseo preferred symmetry, whereas those at Youngdong preferred asymmetry. And every floor plan of catholic churches is rectangular type with transepts except one semicircular type. In apse shape, catholic churches in the Youngseo area preferred non-extruded types like a straight wall, whereas those in Youngdong have extruded types. Every catholic churches have no crypt under ground except one at Gangreung. Except one at Sokcho, every catholic church in this study has choir space in half story.

확률모형과 수식정보를 이용한 와/과 병렬사구 범위결정 (Range Detection of Wa/Kwa Parallel Noun Phrase using a Probabilistic Model and Modification Information)

  • 최용석;신지애;최기선
    • 한국정보과학회논문지:소프트웨어및응용
    • /
    • 제35권2호
    • /
    • pp.128-136
    • /
    • 2008
  • 한국어 구문 분석의 초기 단계로서 병렬구조의 해석은 파싱의 효율을 높일 수 있다. 본 논문은 병렬구조 해석을 위한 비지도식 언어에 독립적인 확률 모델을 제안한다. 이 모델은 병렬구조의 대칭성과 상호교환성에 근거한다. 대칭성은 같은 구조가 반복된다는 것이고, 교환성은 좌우 구성요소를 교환해도 같은 의미를 지닌다는 것이다. 병렬구조는 일반적으로 대칭성을 따르지만, 수식어의 성질에 따라서 한쪽만을 수식하는 비대칭적인 구조가 출현하기도 한다. 비대칭 병렬구조 해석을 위해서 추가적으로 수식관계 통계정보를 사용한다. 제안된 모델을 본 논문에서는 "와/과" 조사로 이루어진 한국어의 명사구 병렬구조를 해석하는데 사용되는 것[1]을 중점으로 보여준다. 지도적 방식에 의한 모델을 포함한 다른 모델들에 비해 효율적임을 실험적으로 보여준다.