• 제목/요약/키워드: involutes

검색결과 5건 처리시간 0.018초

A Characterization of Involutes and Evolutes of a Given Curve in 𝔼n

  • Ozturk, Gunay;Arslan, Kadri;Bulca, Betul
    • Kyungpook Mathematical Journal
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    • 제58권1호
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    • pp.117-135
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    • 2018
  • The orthogonal trajectories of the first tangents of the curve are called the involutes of x. The hyperspheres which have higher order contact with a curve x are known osculating hyperspheres of x. The centers of osculating hyperspheres form a curve which is called generalized evolute of the given curve x in n-dimensional Euclidean space ${\mathbb{E}}^n$. In the present study, we give a characterization of involute curves of order k (resp. evolute curves) of the given curve x in n-dimensional Euclidean space ${\mathbb{E}}^n$. Further, we obtain some results on these type of curves in ${\mathbb{E}}^3$ and ${\mathbb{E}}^4$, respectively.

A NEW DESCRIPTION OF SPHERICAL IMAGES ASSOCIATED WITH MINIMAL CURVES IN THE COMPLEX SPACE ℂ4

  • Yilmaz, Suha;Unluturk, Yasin
    • 호남수학학술지
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    • 제44권1호
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    • pp.121-134
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    • 2022
  • In this study, we obtain the spherical images of minimal curves in the complex space in ℂ4 which are obtained by translating Cartan frame vector fields to the centre of hypersphere, and present their properties such as becoming isotropic cubic, pseudo helix, and spherical involutes. Also, we examine minimal curves which are characterized by a system of differential equations.

A Giant Keratoacanthoma Treated with Surgical Excision

  • Park, Hyochun;Park, Hannara;Kim, Hoonnam;Yeo, Hyeonjung
    • 대한두개안면성형외과학회지
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    • 제16권2호
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    • pp.92-95
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    • 2015
  • A keratoacanthoma is a rapidly growing cutaneous tumor that spontaneously involutes in most instances. A giant keratoacanthoma is a rare variant and are characterized by lesions larger than 20 mm in diameter. We report a 56-year-old man with a rapidly growing tumor of the right cheek, which was diagnosed as keratoacanthoma. The mass was excised completely under general anesthesia, followed by Limberg flap for reconstruction. Intraoperative frozen section histology suggested the lesion to be a well-differentiated squamous cell carcinoma, whereas final histopathology was consistent with keratoacanthoma. We herein report the first case of a giant keratoacanthoma treated with surgical excision in Korea and discuss the clinical and histopathological features of keratoacanthoma, with a review of the literature.

정중 동맥에 의한 수근관 증후군에서 초음파 검사의 유용성: 증례 보고 (Usefulness of Ultrasonographic Examination in Carpal Tunnel Syndrome Caused by a Median Artery: A Case Report)

  • 최병산;김채근;김영진;채수욱;김종윤;차명수
    • 대한정형외과 초음파학회지
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    • 제5권2호
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    • pp.99-101
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    • 2012
  • 정중 동맥은 전완 및 완관절에서 정상적으로 태생 전에 사라져 성인에서 수근관 내에 존재하는 정중 동맥은 드물다. 저자들은 수근관 증후군 환자에 시행한 초음파 검사에서 수근관 내에 정중 동맥이 관찰 되어 보고한다.

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Intraosseous Calcaneal Lipoma with Subtalar Perforation through Cystic Degeneration: A Case Report

  • Kumar, Abhishek;Stephanie, Stephanie;Choi, Jun Young;Chang, Sunhee;Suh, Jin Soo
    • 대한족부족관절학회지
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    • 제19권1호
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    • pp.27-31
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    • 2015
  • Intraosseous lipoma is a benign tumor that originates from proliferating mature lipocytes. It often occurs in the metaphysis of long bones of the lower extremity, and also in the calcaneus, humerus, mandible, sacrum, and rib bones. Frequently, it involutes spontaneously through a process of infarction, calcification, and cyst formation. It can either present as pain, or be asymptomatic and only discovered through an incidental radiological finding. In our case, the patient presented with heel pain. Intraoperatively, it was found that the intraosseous cavity was filled with fat along with an adjacent but separate area of cystic degeneration. There was also a cortical perforation at the cystic lesion which was communicating with the subtalar joint. This cortical breach is most likely the cause of diffuse lateral heel pain experienced by our patient, and such a pathological fracture due to intraosseous lipoma has never been reported.