• 제목/요약/키워드: geometrical form

검색결과 311건 처리시간 0.02초

On the snap-buckling phenomenon in nanocomposite curved tubes

  • Dan Chen;Jun Shao;Zhengrong Xu;Hadi Babaei
    • Structural Engineering and Mechanics
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    • 제89권1호
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    • pp.13-22
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    • 2024
  • The nonlinear snap-through buckling of functionally graded (FG) carbon nanotube reinforced composite (CNTRC) curved tubes is analytically investigated in this research. It is assumed that the FG-CNTRC curved tube is supported on a three-parameter nonlinear elastic foundation and is subjected to the uniformly distributed pressure and thermal loads. Properties of the curved nanocomposite tube are distributed across the radius of the pipe and are given by means of a refined rule of mixtures approach. It is also assumed that all thermomechanical properties of the nanocomposite tube are temperature-dependent. The governing equations of the curved tube are obtained using a higher-order shear deformation theory, where the traction free boundary conditions are satisfied on the top and bottom surfaces of the tube. The von Kármán type of geometrical non-linearity is included into the formulation to consider the large deflection in the curved tube. Equations of motion are solved using the two-step perturbation technique for nanocomposite curved tubes which are simply-supported and clamped. Closed-form expressions are provided to estimate the snap-buckling resistance of FG-CNTRC curved pipes rested on nonlinear elastic foundation in thermal environment. Numerical results are given to explore the effects of the distribution pattern and volume fraction of CNTs, thermal field, foundation stiffnesses, and geometrical parameters on the instability of the curved nanocomposite tube.

파면굴절력 교정을 위한 자유형상 누진가입도렌즈 개발 (Development of Free-form PALs for Correcting Wavefront Refraction)

  • 박상배;정미숙
    • 한국정밀공학회지
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    • 제27권2호
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    • pp.50-59
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    • 2010
  • In this paper, two kind of free-form progressive addition lenses (PALs) were designed with Zernike polynomial surface and anatomically accurate finite presbyopic schematic eyes which have aspheric cornea, aspheric GRIN crystalline lens, aspheric retina, and Gaussian apodization factor. Geometrical and diffraction MTFs were used for the optimization process in sequence. 5th orders of Zernike polynomials were used for the evaluation of progression zones of the two examples. The target MTF was set as 0.22 at 100 lp/mm which satisfies the standard visual resolution. These examples were fabricated with a CNC diamond turning machine controlled by slow tool servo (STS). After polishing process, the wavefront aberrations were measured with a laser interferometer on the ten test points across the progression zones and then compared with three current commercially available PALs on the optical performance. Astigmatic aberrations of the examples are very lower than the three selected PALs and have more increased stabilized progressive intermediate zones and near zones. It is expected to give better clear and comfortable distance, intermediate and near visions than other conventional PALs and to improve the adaptability of presbyopic patients to PALs.

모더니즘 조경설계에 미친 미술의 영향에 관한 연구 (A Study on the Influences of Fine Art On Modern Landscape Design)

  • 김한배
    • 한국조경학회지
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    • 제29권4호
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    • pp.53-66
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    • 2001
  • Modern art has had a great impact on the concepts and the formal attributes of modern landscape design. This study aimed at examining the origins of modern landscape design languages especially in relation to the influence of find art during the modernist age. The formal reductionism of Cubistic paintings finally lead to the formulation of Geometrical Abstractionism which became the basic formal model for ˝Regular Style˝; one of the representative modern landscape style. This Regular Style is mostly based on the formal structure of ´Grids´, which was developed by many landscape designer like Eckbo, Kley and Halprin. On the other hand, the ´Bio-morphic Form´ originally used in Surrealistic Art became the formal model for ˝Organic Style˝; the other representative modern landscape style, developed mostly by the landscape designers like Church, Burle-Mark and Bye. Thus, ´Grids´ and ´Bio-morphic Form´ became the dual icons of modern art and modern landscape design. Although these modern landscape design styles were ground breaking departure from the conventional formal/informal tradition and expanded possibilities in formal experimentations, They also produced several crucial limitations originated from the scientific reductionism and autonomous aesthetics of modern art, like the physical and cultural discontinuation from surrounding environments and the formal alienation from the real life world, which gave rise to the emergence of post-modern thinking of landscape design.

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1920년대 소비에트 구성주의 패션에 관한 연구 (A Study on Soviet Constructive Fashion in 1920s)

  • 조윤경;금기숙
    • 복식
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    • 제36권
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    • pp.183-203
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    • 1998
  • The wave of Avant-garde swept away all in the unique social background so called 'October Revolution' and the early 1900 Russian society which was able to absorb and accept anything. The Russian avant-garde has been affected by the Cubism and the Futurism those had peculiarly appeared in the early twentieth century, spreaded out to three spheres: the Suprematism, the Rayonism and the Constructivism. The Russian Constructivism has appeared in this background, concretely and ideally ex-pressed the ideology of the revolution into the artistic form and made an huge influence to the whole Russian society. The Constructivist like Tatlin, naum Gabo, Pevaner, Rodchenko, Stepanova, Popova and Exter gave great effect on the Soviet Constructive fashion design in 1920's after the Revolution. The Soviet costume in 1920s hold in common the characteristicss of the Constructive graphic as it is, geometrical and abstractive form, energetic and motility. In fashion design, these graphic qualities have been showed as the application of geometrical form and architectural image, physical distortion and transformation. And in textile design, the simple, dynamical presentation has been appeared. We can classify the Soviet costume at this time into three occasions. The first term is from late 1910 th mid 1920, and it is altered from folk costume design to modern one. With Lamanova as the first on the list, using the folk mitif, the Constructive expression of simple form has been gradually revealed in design. Designers like Makarova, Pribylskaia and Mukhina produced the plane, simple chemise style with the decoration of the Russian traditional motif. From early to late 1920 is the second term, and it is at the pick of the most active processing of the Constructive design. Not only at the costume in daily life but also at the theatrical costume and textile, the con-structive design has been represented all avail-able fields. Many Constructivists including Stepanova, Popova, Exter and Rodchenko took part in the textile design and costume design so as to evlvo their aesthetic concept. The third term is from late 1920 to early 1930. The socialistic realism has dominated over the whole culture and art, the revolutionary dynamic motif has been presented also in textile design. The formative features of Soviet Constructive fashion design are; silhouette, from, motif, color and fabric. The first, the silhouette : a straight rectangular silhouetted has been expressed through the whole period and a volumed one with distorted human body shape has introduced in the theatrical costume design. The second, the form: many lengthened rectangular forms have been made at beginnings, but to the middle period, geometrical, architectural forms have been more showed and there are energy and movement in design. At the last period, only a partial feature-division has been seen. The third, the motif; no pattern or ethnic motif has been partly used at beginnings, a figure like circle, tri-angle has gradually appeared in textile design. At latter period, a real-existent motif like an airplane has been represented with graphing and simplicity. The fourth, the color ; because of insufficient dyeing, neutral color like black or grey color has been mainly covered, but after middle term, a primary color or pastel tone has been seen, contrast of the fabric; without much development of textile industry after the Revolution, thick and durable fabrics have been the main stream, but as time had going to the last period, fabrics such as linen, cotton, velvet and silk have been varously choesn. At the theatrical costume, new materials like plastics and metals that were able to accentuate the form. The pursuit of popularity, simplicity and functionalism that the basic concept of Constructive fashion is one of the "beauty" which has been searching in modern fashion. And now we can appreciate how innovative and epochal this Soviet Constructive fashion movement was.ement was.

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브루넬레스키의 산타 마리아 델 휘오레 교회의 돔계획에 관한 연구 (A Study on the Dome Plan of S. M. del Fiore Church of F. Brunelleschi)

  • 김석만
    • 건축역사연구
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    • 제21권5호
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    • pp.19-32
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    • 2012
  • The purpose of this paper is a study on the dome plan of S. M. del Fiore Church of F. Brunelleschi. The results of study are as follows: 1. The planning of floor, elevation and cross section plan of S. M. del Fiore church is basically planned by each other correlation. In particular, the octangular form of geometrical standard which is formed with altar as the center at the crossing part is important component elements which is decided by not only the dome, but form and size of the drum and floor plan form of the lantern 2. The dome which has been planned by F. Brunelleshi has completed the new dome, preserving gothic thought intended by the church plan after study on architecture of ancient Rome with Pantheon. And the dome which is a main space of church through all aspects of plan, structure, function and construction about the dome is a opportunity in the beginning of Renaissance architecture which is a new epoch and a turning point of architecture on various point of view. 3. The dome which is constructed by F. Brunelleshi has been planned through the innovative solution by the refusal of traditional semicircle form dome, centering use and creation double-shell structure form for the first time in history. And the construction of dome has been solved with the invention of various construction equipments and machineries, the stone rib planned for connection and reinforcement about shells of the octangular form, the support method for reduction the gravity of bricklayers work and the brick work of nock-patterned shape which is masonry construction method of the architecture of ancient Rome.

메쉬 반사판 안테나의 케이블 네트 형상 설계 및 변형 해석 (Form-finding and Deformation Analysis of the Cable Nets for Mesh Reflector Antennas)

  • 노진호;최혜윤;정화영;송덕기;윤지현
    • 한국항공우주학회지
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    • 제50권9호
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    • pp.609-616
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    • 2022
  • 메쉬 반사판 안테나의 성능은 반사판 표면의 형상 오차에 크게 의존하게 된다. FDM(Force Density Method)을 이용하여 반사판 케이블 네트의 형상설계 연구가 수행되고 있다. 하지만 결정된 형상 일부에 반사판 실효면적의 감소가 발생하고, 케이블의 기하학적 비선형을 고려한 변형 해석은 불가능하다. 본 연구에서는 기하학적 특성을 고려한 케이블 네트 형상설계 방법론을 제시하고 설계된 형상의 실효성을 검증한다. 기하학적 비선형성을 고려한 케이블 네트의 유한요소 모델을 개발한다. 경계조건의 하중 변화에 따른 형상변형 해석을 통하여 케이블 네트 형상 설계변수 특성을 제시하고자 한다.

현대 패션에 나타난 주술적 원시미술의 조형적 특성 연구 (A Study on the Formative Characteristics of Enchanting Primitive Art in Modern Fashion)

  • 이은경;김양원
    • 한국생활과학회지
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    • 제8권2호
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    • pp.327-337
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    • 1999
  • Primitive men's primordial formative activity derives from incarnation contained in intensive vitality and strong creativity mind. The trend of modern fashion requiring the boundless imagination can be called that it, just, itself, has something in common with basic spiritual activity that primitive men had. What is concerning how modern fashion designers have developed formative language through enchanting primitive art is as follows. 1. The nature's mysterious power appears to be transformed into personified image. The incarnation for acquiring beauty, power, prestige of genius appears in the form of personification, making use of mask in modern fashion. 2. As for primitive men, the whole universe has a potentiality as a symbol. The symbolism of primitive art based on religion and myth appears in modern art as the form of presenting oppositional objects together in one space. 3. Primitive art is the purest form and the most unpolluted. This shows the natural quality being assimilated into nature, which is expressed in modern fashion as intensity, free-spirit, simplicity, etc. 4. The primitive men's anxiety to the outside world appears as impulse. The geometrical form of primitive art occurred in the shape of impulse appears in expressional form of modern fashion. 5. The real existence in primitive art inducing real materials and objects, in themselves, into formative world appears in modern art in the way of expression such as repetition, enlargement, exact reproduction.

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1990년대 패션에 나타난 오리엔탈리즘에 관한연구 (A Study on the Orientalism Expressed in the Fashion of 1990's)

  • 은영자
    • 복식
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    • 제43권
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    • pp.259-282
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    • 1999
  • To analyze the characteristics of Orientalism which is expressed in the fashion of the 1990's this study was examined according to three aspects such as form textiles and pattern and the aspects was considered with regard to Chinese Indian Japanese Korean, Southeas Asian and North African style. 1. In form Orientalism which is influenced by latest other fashion trend; Naturalism and Minimalism is expressed as a comfortable casual style which simplifies the way of wearing and mixes the characteristic elements of folk costume with western costume. The way of layerd wearing like knotting wrapping draping and the symbolic from which is inspired by the unique are of each country are shown. 2. In textiles Chinese Japanese and Indian silk as well as Southeast Asian and North African cotton show a splendid oriental impression using vivid color. On the other hand the linens of Korea like hemp and ramie emphasize natural characteristics and show a simple and unartificial oriental beauty. But in the use of material and color it shows a remarkable tendency to break the preconceived idea by coordinating a luxurious silk with a practical denim or harmonizing technical new-masterials with traditional materials. 3. In pattern the decorative elements of Orientalism such as a traditional pattern skills to dye embroidery and other decorations are emphasized on the form of western costume. The sketchy patterns of Chinese Korean and Japanese styles which include the pattern of a flower a bamboo and a butterfly are expressed using embroidery or textile printing. The geometrical seriate patterns of Southeast Asian and North African styles use traditional dyeing methods like Batik. Also the Indian technique of decoration like Mirro Work satisfies handcrafted royalty and feminine romantic taste in modern minimal fashion. The Orientalism expressed in the fashion of 1990's emphasizes the characteristics of people wearing colthing which break the preconceived idea by simplifying the form harmonizing differences between oriental and western cultures and mixing the elements of traditional costumes among countries. Most of all. Ethno using geonmetrical seriate pattern and technical new metal material and Romantic Ethnic using flower embroidery precious stones and beads are appearing as a distinctinve feature.

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알켄-오존 반응의 중간 생성물에 대한 ab initio 양자역학적 고찰 (Quantum Mechanical Investigation on the Intermediates of Alkene-Ozone Reaction)

  • 강창덕;김승준
    • 대한화학회지
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    • 제42권2호
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    • pp.161-171
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    • 1998
  • 알켄-오존 반응에서 생성된 중간 생성물로써 primary ozonide (POZ),secondary ozonide (SOZ)그리고 carbonyl oxide의 분자구조, vibrational frequencies그리고 infrared(IR)스펙트럼의 세기 등에 대한 이론적 연구를 high level ab initio 양자역학적 방법(CISD,CCSD)을 사용하여 수행하였다. 일반적으로, polarization function은 결합각과 결합길이를 감소시키는 경향을 보였고 반면, electron correlation effect는 결합길이와 결합각을 약간 증가시키는 경향을 보이고 있다. Carbonyl oxide의 분자구조는 zwitterionic form이 diradical form보다 더 안정한 것으로 예측되었으며, 두 형태의 에너지는 차이는 TZ2P CISD level에서 약 22.4 kcal/mol인 것으로 계산되었다. 또한, POZ과 SOZ의 분자구조 및 harmonic vibrational frequencies들을 실험결과와 비교 분석하였으며 IR세기에 근거하여 각 vibrational mode를 assign 하였다.

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ART DECO 양식의 FASHION 과 장신구에 관한 연구 (A Study on the Fashion & Jewelry in the Art Deco Style)

  • 김은주;최덕환
    • 복식
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    • 제39권
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    • pp.239-255
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    • 1998
  • Art deco means decorative form on the base of cubism which has widely spread from 1910's to 1930's. Also it pursued the rational & functional design even than deecoration of art nouvear, and colorful combination of fauvism. The analytical study on design included occurrence, developing process and formative features expressed in the art deco fashion. The changes of the art deco style, it referred to the fashion illustration which was the Graphic-s of Ert in 19 century. Besides analysised activity designer in the art deco style, at the same time considered fashion design as comparable analysis. Paul Poiret, a representative french designer, contributed to the clothing culture which accepted oriental influence and it was all the fashion enough to call the originator of present fashion. He did away with the corset, relaxed the waistline, and freed the body from clothing constrictions of almost a hundred years. Since 1914, because of industry of woman clothing that art deco represent concern of one's Chanel's perennial rival in the firmanent of parisian high fashion was the Italian designers, Elsa Schiaparelli, Schiaparelli's originalily was profoundly influenced by the avant-garde art of the time ; Da da and Surealism were principal soures of new ideas. It apply the style to geometrical or abstract form impressed straight and smooth line on suitable technic. Such inflection of art deco heralded a close collaboration between the artist-jeweller and the fashion industry. Especially, jewelry designers were fond of juxtaposing transparent faceted stoned which reflected the light, with matt stones, which offered rare or unconventional contrasts through their opacity. Consequently, art deco will exert value of utility for the progressive fashion & jewel CAD through continuous research.

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