• Title/Summary/Keyword: R+-트리

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The Reaction of the Tripledecker Complexes, 4(CpCo)_2(C_4R_4)$ and Alkynes (Tripledecker 착물, $(CpCo)_2(C_4R_4)$과 Alkyne과의 반응)

  • Uhm, Jae-Kook;Lee, Won-Sik;Kim, Seog-Bong;Cha, Jin-Soon;Lee, Hyung-Soo;Lee, Dong-Ho;Kim, Hong-Seok;Sim, Sang-Chul
    • Journal of the Korean Chemical Society
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    • v.37 no.9
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    • pp.832-836
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    • 1993
  • The tripledecker complexes, bis-(${\eta}^5-cyclopentadienyl)-{\mu}-({\eta}^4-1,2,3,4-tetraalkylcyclobutadiene$)dicobalt were produced by the reaction of Jonas reagent with 2-hexyne and 3-hexyne in the maximum yield (above 50%) when they were reacted in eq-molar amounts at room temperature. A tripledecker complex, bis-${\eta}^5-cyclopentadienyl)-{\mu}-({\eta}^4-1,2,3,4-tetraethyl cyclobutadiene$)dicobalt(13) was isomerized to (${\eta}^5-cyclopentadienyl)cobaltacyclopentadiene-{\mu}-({\eta}^4-2,4-cobaltacyclopentadiene$)(${\eta}^5-cyclopentadienyl$)cobalt(15) on reacting with 3-hexyne at room temperature. Another tripledecker complex, bis-(${\eta}^5-cyclopentadienyl)-{\mu}-({\eta}^4-1,3-dimethyl-2,4-dipropyl cyclobutadiene$)dicobalt(14) was decomposed to give 1,3,5-trimethyl-2,4,6-tripropylbenzene through an intermediate complex by the reaction of 2-hexyne.

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Preparation and Polymerization of Alkenylsilanes (Alkenylsilane의 제조와 고분자화반응)

  • Kim, Chung Kyun;Choi, Soon Kyu;Park, Eun Mi;Jung, In Kyung
    • Journal of the Korean Chemical Society
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    • v.41 no.2
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    • pp.88-97
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    • 1997
  • The silyltriflates$(Ph_{3-n}SiH(OTf)_n)$have been produced by the reaction of triphenylsilane and triflic acid$(CF_3SO_3H)$at low temperature. These highly reactive compounds are a valuable reagent for the synthesis of numerous new functional substituted silane derivatives. The reaction of silyltriflates with alkenyl- and alkynylmagnesium bromide as well as organolithium compounds gave new silanes$Ph_2SiHR(R=\;C(CPh,\;CH=CH_2,\;CH_2CH=CH_2,\; (CH_2)_2CH=CH_2,\;(CH_2)_3CH=CH_2)$in high yields. The hydrosilation of prepared alkenyl- and alkynylsilanesPh_2SiHR$in the presence of a platinum catalyst(Pt/C) at high temperature$(200{\circ}C)$gave carbosilane polymers$((Ph_2SiCH=CPh)_n$and$(Ph_2Si(CH_2)m)n;\;m=2∼4, n{\ge}10)$along with five- and six-membered silaalkane ring compounds derived from intramolecular hydrosilation reactions. All of the prepared compounds are confirmed by NMR, UV, IR and mass spectroscopy as well as elemental analysis.

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A Study of Performance Decision Factor for Moving Object Database in Main Memory Index (이동체 데이터베이스를 위한 메인 메모리 색인의 성능 결정 요소에 관한 연구)

  • Lee, Chang-Woo;Ahn, Kyoung-Hwan;Hong, Bong-Hee
    • Annual Conference of KIPS
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    • 2003.05c
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    • pp.1575-1578
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    • 2003
  • 이동통신 기술의 발달로 인하여 무선 이동 기기의 사용이 보편화되면서 LBS(Location Based System)의 요구가 나날이 증대되고 있다. 이와 같은 위치 기반 서비스에서 클라이언트인 이동체들은 일정한 보고 주기를 가지고 서버에 위치 데이터를 보고하게 되는데, 빈번한 보고 데이터를 실시간으로 처리하기 위해서 서버에서는 메인 메모리 DBMS를 유지하는 것이 필요하다. 기존에 제시된 메인 메모리 색인으로는 T-tree 가 있는데, 이는 1차원 데이터를 위한 것이므로 이동체 데이터베이스 환경에 적합하지 못하다. 그리고, 디스크 기반의 다차원 색인으로는 R-tree 계열이 있는데, 이는 메인 메모리에서 효율적인 사용을 보장하지 못한다. 이 논문에서는 이동체 데이터베이스 환경에 적합한 메인 메모리 색인을 고려함에 있어서, 기존의 디스크 기반의 다차원 색인으로 가장 널리 알려진 R-tree 계열의 색인을 메인 메모리에 적재 후 메인 메모리 환경에서 성능에 영향을 주는 요소를 실험을 통하여 제시한다. 실험은 메인 메모리에서는 간단한 알고리즘을 사용하는 것이 성능에 좋고, 삽입 시에는 삽입할 노드를 찾기 위해서 비교하는 엔트리의 수가, 검색 시에는 노드간의 중첩으로 인하여 비교하는 노드의 수와 엔트리의 수가 성능에 영향을 주는 요소임을 보여준다.

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A New Yellow Color Grafted Cactus (Chamaecereus silvestrii) Cultivar "Yellow Tree" (접목선인장 황색계 산취 신품종 "옐로우트리" 육성)

  • Cho, Chang-Hui;Nam, Sang-Yong;Lee, Sang-Deok;Park, Heung-Bae
    • Korean Journal of Breeding Science
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    • v.40 no.4
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    • pp.521-524
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    • 2008
  • A new graft cactus (Chamaecereus silvestrii f. variegata) cultivars "Yellow Ttree" was developed at Cactus Research Institute, Gyeonggi-do A.R.E.S. in 2007. GC013001 and GC0110703 were crossed in 2005 and we got 42 seedlings from this combination. After pedigree selection in 2005, one cultivar were finally selected through the test of specific character in 2007 and named as "Yellow Ttree". "Yellow Ttree" has cylindrical shape of yellow color with 13~14 ribs. Formation of its offshoots is concentrated on the lower part of the plant. This cultivar is able to produce 13.9 offsets shoots per plant and its offshoots are hard.

Research on Security Requirements for Unmanned Ground Vehicles from an Incident-Induced Perspective (사고 유발 관점에서의 무인지상차량 보안 요구사항에 관한 연구)

  • Dong-hoon Kim;Sang-jin Lee
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.34 no.5
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    • pp.1135-1148
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    • 2024
  • This paper derives security requirements to ensure the safe operation of unmanned ground vehicles from the perspective of accident causation through threat modeling. By analyzing the components of unmanned ground vehicles and identifying potential vulnerabilities in each element, we constructs attack trees that could lead to accidents such as collisions and sudden stops. From these attack trees, security requirements are derived. These requirements are then compared with the security requirements corresponding to accident causation threats as outlined in the UN's document on autonomous vehicle threats and security requirements, UN R155 Annex 5. The comparison highlights how the security requirements proposed in this paper align with those established by the UN. The application of the security requirements proposed in this paper is expected to facilitate the smooth introduction and operation of unmanned ground vehicles.

An Concurrency Control Technique Based on Version Techniques for Non Blocking Queries in R-Tree (R-Tree에서 지연 없는 검색을 위한 버전 기반의 동시성 제어 기법)

  • Jin, Min-Sheng;Kim, Myoung-Keun;Ba, Hae-young
    • Annual Conference of KIPS
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    • 2004.05a
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    • pp.101-104
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    • 2004
  • R-Tree 색인은 기존의 공간 데이터베이스관리시스템에서 공간 데이터 검색을 위하여 많이 사용되고 있는 공간 색인기법이다. 하지만 R-Tree 색인에서 기존의 잠금(Lock) 기반 동시성 제어는 갱신연산의 잠금으로 인해 검색연산의 블록킹 오버헤드(blocking overhead)가 발생한다. 본 논문에서는 R-Tree 색인에서 검색연산의 블록킹 오버헤드의 주요 원인이 되는 노드 분할 연산과 MBR(Minimum Bounding Rectangle) 갱신연산에 대해 각각 노드단위와 노드엔트리 단위의 버전(Version)을 생성하고 유지하여 동시에 발생하는 검색연산이 갱신연산으로 인한 지연이 없이 자신에 알맞은 버전을 읽음으로써, 검색성능을 높일 수 있는 버전 기반의 동시성 제어 기법을 제안한다.

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Comparison research of the Spatial Indexing Methods for ORDBMS in Embedded Systems (임베디드 시스템의 객체 관계형 DBMS에 적합한 공간 인덱스 방법 비교 연구)

  • Lee, Min-Woo;Park, Soo-Hong
    • Journal of the Korean Association of Geographic Information Studies
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    • v.8 no.1
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    • pp.63-74
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    • 2005
  • The telematics device, which is a typical embedded system on the transportation or vehicle, requires the embedded spatial DBMS based on RTOS (Real Time Operating System) for processing the huge spatial data in real time. This spatial DBMS can be developed very easily by SQL3 functions of the ORDBMS such as UDT (user-defined type) and UDF (user-defined function). However, developing index suitable for the embedded spatial DBMS is very difficult. This is due to the fact that there is no built-in SQL3 functions to construct spatial indexes. In this study, we compare and analyze both Generalized Search Tree and Relational Indexing methods which are suggested as common ways of developing User-Defined Indexes nowadays. Two implementations of R-Tree based on each method were done and region query performance test results were evaluated for suggesting a suitable indexing method of an embedded spatial DBMS, especially for telematics devices.

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Crossability and Chromosome Variation in the Early Generation of the Crosses between the Hexaploid Triticale and Diploid Rye (6배체 트리티케일 2배체 호밀과의 잡종 초기세대에서 교잡 친화성 및 염색체 변이)

  • 황종진;이홍석;하용웅
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.36 no.6
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    • pp.485-495
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    • 1991
  • This experiment was carried out to obtain the information on the crossability, variation of chromosome number in pollen mother cell (PMC) and somatic cell of the progeny from the cross between hexaploid triticale cv. Sinkihomil and two diploid rye varieties. Seed set was 39.3 to 41.6% (averaged 40.5%) in the cross between triticale (P$_1$) and rye(P$_2$), which resulted in 0.33% in F$_2$(selfed F$_1$), 2.69% in F$_1$/P$_1$ 5.47% in F$_1$/P$_2$ respectively. However, seed set was extremely low in both reciprocal crosses when triticale was used as male. Germination rate of the crossed seed was 94.0% in F$_1$ 40.8% in F$_2$(selfed F$_1$), 59.5% in F$_1$/P$_1$ and 65.9% in F$_1$/P$_2$ from the cross between triticale and rye, respectively. Pollen fertility of F$_1$ plant was averaged 18.7% in the cross between triticale and rye. Number of Uni-, Bi-, and Trivalent in PMC was 12. 6, 6.94, and 0.53, respectively, in the F$_1$ between the triticale and rye. There were 28 chromosomes in F$_1$, 21 to 34 in F$_2$, 34 to 38 in F$_1$/P$_1$ and 19 to 23 in F$_1$/P$_2$ from the cross between the triticale and rye, respectively.

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Method Development for Determination of Trichothecene Mycotoxins in Nuts by LC-MS/MS (LC-MS/MS를 이용한 견과류 중 트리코테센계 곰팡이 독소 10종 동시분석법 개발)

  • Kim, Dan-Bi;Park, Ji-Su;Yoo, Mi-Young
    • Journal of Food Hygiene and Safety
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    • v.33 no.5
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    • pp.354-360
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    • 2018
  • This study presents a method validation for extraction and quantitative analysis of trichothecene mycotoxins in nuts based on quick, easy, cheap, effective, rugged, and safe (QuEChERS) approach for extraction and enhanced matrix removal (EMR)-lipid-disperive-SPE (d-SPE) cleanup method, with detection and quantification by high-performance liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) in positive- and negative-ion modes. Linearity, precision, and accuracy were validated for LC-MS/MS methods. Results obtained with LC-MS/MS were linear, with correlation coefficient ($R^2$) of 0.998. Limits of detection and quantification for mycotoxins were $0.41-3.57{\mu}g/kg$ and $1.23-10.82{\mu}g/kg$, respectively. Intra- and inter-day precisions (RSD, %) were 0.40-8.44% and 1.93-12.46%, respectively. Results indicated to be rapidly and accurately identifying trichothecene mycotoxins and may be used as a suitable safety management method for nuts and nuts related commodities.