• Title/Summary/Keyword: $S_nO_n$

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Phytosociological Studies on the Beech(Fagus multinervis Nakai) Forest and the Pine (Pinus parviflora S. et Z.) Forest of Ulreung Island, Korea (한국 울릉도의 너도밤나무(Fagus multinervis Nakai)림 및 섬잣나무(Pinus parviflora S. et Z.)림의 식물사회학적 연구)

  • 김성덕
    • Journal of Plant Biology
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    • v.29 no.1
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    • pp.53-65
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    • 1986
  • The montane forests of Ulreung Island, Korea, were investigated by the ZM school method. By comparing the montane forests of this island with those of Korean Peninsula and of Japan, a new order, F a g e t a l i a m u l t i n e r v i s, a new alliance, F a l g i o n m u l t i n e r v i s, a new association, H e p a t i c o-F a g e t u m m u l t i n e r v i s and Rhododendron brachycarpum-Pinus parviflora community were recognized. The H e p a t i c o - F a g e t u m m u l t i n e r v i s was further subdivided into four subassociations; Subass. of Sasa kurilensis, Subass. of Rumohra standishii, Subass. of Rhododendron brachycarpum and Subass. of typicum. Each community was described in terms of floristic, structural and environmental features.

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Dichloro, Alanine and S-Methylcysteine Cobalt (III) Complexes of Ethylenediamine-N,N$^\prime$-di-$\alpha$-isobutyric Acid

  • Jun, Moo-Jim;Park, Chang-Woo;Park, Youn-Bong;Cheon, Jin-Woo;Choi, Sung-Rack
    • Bulletin of the Korean Chemical Society
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    • v.11 no.4
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    • pp.354-357
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    • 1990
  • Synthesis of dichloro cobalt (Ⅲ) complexes of a flexible $N_2O_2-type$ tetradentate ligand, ethylenediamene-N,N'-di-${\alpha}$-isobutyric acid (eddib), has yielded two geometrical isomers, s-cis-$(Co(eddib)Cl_2)- and uns-cis-(Co(eddib)Cl_2)-.$ A series of substitution reactions, $(Co(eddib)Cl_2)^- {\to} (CO(eddib)Cl H_2O) {\to} (Co(eddib)CO_3)^- {\to} (Co(eddib(H_2O)_2)^+$ have been run for each of the two geometrical isomers. The reaction between the s-cis-(Co(eddib)Cl_2)^-$ complex and L-alanine (L-als) or S-methyl-L-cysteine (L-mcy) gave the meridional s-cis-[Co(eddib)(aa)) (aa = L-ala or L-mcy) complex. The S-methyl-L-cysteine was found to coordinate to cobalt (Ⅲ) ion via the nitrogen and oxygen donor atoms.

CONVOLUTION SUMS OF ODD AND EVEN DIVISOR FUNCTIONS

  • Kim, Daeyeoul
    • Honam Mathematical Journal
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    • v.35 no.3
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    • pp.445-506
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    • 2013
  • Let ${\sigma}_s(N)$ denote the sum of the s-th power of the positive divisors of N and ${\sigma}_{s,r}(N;m)={\sum_{d{\mid}N\\d{\equiv}r\;mod\;m}}\;d^s$ with $N,m,r,s,d{\in}\mathbb{Z}$, $d,s$ > 0 and $r{\geq}0$. In a celebrated paper [33], Ramanuja proved $\sum_{k=1}^{N-1}{\sigma}_1(k){\sigma}_1(N-k)=\frac{5}{12}{\sigma}_3(N)+\frac{1}{12}{\sigma}_1(N)-\frac{6}{12}N{\sigma}_1(N)$ using elementary arguments. The coefficients' relation in this identity ($\frac{5}{12}+\frac{1}{12}-\frac{6}{12}=0$) motivated us to write this article. In this article, we found the convolution sums $\sum_{k<N/m}{\sigma}_{1,i}(dk;2){\sigma}_{1,j}(N-mk;2)$ for odd and even divisor functions with $i,j=0,1$, $m=1,2,4$, and $d{\mid}m$. If N is an odd positive integer, $i,j=0,1$, $m=1,2,4$, $s=0,1,2$, and $d{\mid}m{\mid}2^s$, then there exist $u,a,b,c{\in}\mathbb{Z}$ satisfying $\sum_{k& lt;2^sN/m}{\sigma}_{1,i}(dk;2){\sigma}_{1,j}(2^sN-mk;2)=\frac{1}{u}[a{\sigma}_3(N)+bN{\sigma}_1(N)+c{\sigma}_1(N)]$ with $a+b+c=0$ and ($u,a,b,c$) = 1(Theorem 1.1). We also give an elementary problem (O) and solve special cases of them in (O) (Corollary 3.27).

Investigation on emission characteristics of nitrous oxide from marine diesel engine (선박용 디젤엔진에서 아산화질소의 배출특성에 대한 연구)

  • Yoo, Dong-Hoon
    • Journal of Advanced Marine Engineering and Technology
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    • v.38 no.9
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    • pp.1051-1056
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    • 2014
  • Nitrous oxide ($N_2O$) is naturally generated from biological activity, such as bacteria's material exchange. However, recent $N_2O$ concentration in the atmosphere has being increased by the human activities such as industrial growth. One of factors to increase $N_2O$ concentration in the atmosphere is a $N_2O$ emission caused by the combustion of marine fuel oils. The marine transportation presently handles over 99 percent of the international freight cargoes and the number of ship is continuously increasing with increment of cargoes. In this study, author conducted a series of the experimental investigations on which combustion of fuels containing different element concentrations used in a 4-stroke marine diesel engine affect $N_2O$ emissions in the exhaust gas. Moreover, it is assessed on the extent to which fuel combustion patterns in the combustion chamber affect $N_2O$ emissions.

A Study on the Effect of Fluidizing Media on the N2O Production in Fluidized Bed Incineration of Sewage Sludge (하수슬러지 유동층 소각에서 유동매체가 N2O 발생에 미치는 영향에 관한 연구)

  • Park, Jong-Ju;Lee, Seung-Jae;Ryu, In-Soo;Jeon, Sang Goo;Park, Yeong-Sung;Moon, Seung-Hyun
    • Clean Technology
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    • v.20 no.4
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    • pp.390-397
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    • 2014
  • This study was performed to investigate the effects of fluidizing media on $N_2O$ production in fluidized bed incineration of sewage sludge. The fluidized media were prepared in a form of 2 mm bead by mixing zeolite powders in our lab. Sand having 0.4 mm of the mean size showed 0.44 m/s of minimum fluidization velocity ($U_{mf}$), while the prepared zeolite media 0.5 m/s. When the ratio of fluidizing media height to the inside diameter of the incinerator (bed aspect ratio) increased from 1.4 to 3.1, it was found that $U_{mf}$ of the zeolite media was varied from 0.5 m/s to 0.7 m/s. Under the operation conditions in 1.79 of excess air ratio, $909^{\circ}C$ of bed temperature and ca. 1.65 m/s of superficial velocity, as the weight of fluidizing meadia was increased, $O_2$ concentration in the flue gas was slightly decreased, and $CO_2$ increased. Above 6 kg of fluidizing media weight (1.98 of bed aspect ratio), it was observed that $N_2O$ concentration was significantly reduced, which might result from the decomposition of $N_2O$ on the zeolite media rather than transformation of $N_2O$ to NOx. On the other hand, in a variation of the zeolite media mixing ratio to sand and bed temperature at a constant total bed height, significant difference was exhibited in $N_2O$ emission concentration according to the temperature. Considering the operation temperature in the incineration, the effective calcination temperature of the zeolite media was suggested to be around $900^{\circ}C$.

Characteristics of the NO/$N_2O$ Nitrided Oxide and Reoxidized Nitrided Oxide for NVSM (비휘발성 기억소자를 위한 NO/$N_2O$ 질화산화막과 재산화 질화산화막의 특성에 관한 연구)

  • 이상은;서춘원;서광열
    • Journal of the Korean Vacuum Society
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    • v.10 no.3
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    • pp.328-334
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    • 2001
  • The characteristics of $NO/N_2O$ nitrided oxide and reoxidized nitrided oxide being studied as super thin gate oxide and gate dielectric layers of nonvolatile semiconductor memory(NVSM) was investigated by dynamic secondary ion mass spectrometry(D-SMS), time-of-flight secondary ion mass spectrometry(ToF-SIMS), and x-ray photoelectron spectroscopy (XPS). The specimen was annealed in $NO/N_2O$ ambient after initial oxide process. The result of D-SIMS exhibits that the center of nitrogen exists at the initial oxide interface and the distribution of nitrogen is wider in the annealing process with $N_2O$ than with NO annealing process. For investigating the condition of nitrogen that exists within the nitrided oxide, ToF-SIMS and XPS analysis were carried out. It was shown that the center of nitrogen investigated by D-SIMS was expected the SiON chemical bonds. The nitrogen near the newly formed reoxide/silicon substrate interface was appeared as $Si_2NO$ chemical bonds, and it is agreed with the distribution of SiN and $Si_2NO$ species by ToF-SIMS.

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Preparation of $M_xZn_{0.22}Fe_{2.78-x}O_4(M=Mn, Ni)$ Films by the Ferrite Plating and Their Magnetic Properties (페라이트 도금법에 의한 $M_xZn_{0.22}Fe_{2.78-x}O_4(M=Mn, Ni)$ 박막의 제조와 자기적 성질)

  • 하태욱;유윤식;김성철;최희락;이정식
    • Journal of the Korean Magnetics Society
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    • v.10 no.3
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    • pp.106-111
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    • 2000
  • The magnetic thin films can be prepared without vacuum process and under the low temperature (<100 $^{\circ}C$) by ferrite plating. We have performed ferrite plating of M $n_{x}$Z $n_{0.22}$F $e_{2.78-x}$ $O_4$(x=0.00~0.08) films and N $i_{x}$Z $n_{0.22}$F $e_{*}$2.78-x/ $O_4$(x=0.00~0.15) films on cover glass at the substrate temperature 90 $^{\circ}C$. The crystal structure of the samples has been identified as a single phase of polycrystal spinel structure by x-ray diffraction technique. The lattice constant in the M $n_{x}$Z $n_{0.22}$F $e_{2.78-x}$ $O_4$films increases but in the N $i_{x}$Z $n_{0.22}$F $e_{*}$2.78-x/ $O_4$films decrease with the composition parameter, x. The saturation magnetization in the M $n_{x}$Z $n_{0.22}$F $e_{2.78-x}$ $O_4$films does not greatly change, in agreement with observations on bulk samples.k samples.k samples.

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Characteristics of A Diaphragm-Type Fiber Optic Fabry-Perot Interferometric Pressure Sensor Using A Dielectric Film (유전체 박막을 이용한 다이아프램형 광섬유 Fabry-Perot 간섭계 압력센서의 특성)

  • Kim, M.G.;Yoo, Y.W.;Kwon, D.H.;Lee, J.H.;Kim, J.S.;Park, J.H.;Chai, Y.Y.;Sohn, B.K.
    • Journal of Sensor Science and Technology
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    • v.7 no.3
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    • pp.147-153
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    • 1998
  • The strain characteristics of a fiber optic Fabry-Perot pressure sensor with high sensitivity using a $Si_{3}N_{4}/SiO_{2}/Si_{3}N_{4}$ (N/O/N) diaphragm is experimentally investigated. A 600 nm thick N/O/N diaphragm was fabricated by silicon anisotropic etching technology in 44 wt% KOH solution. An interferometric fiber optic pressure sensor has been manufactured by using a fiber optic Fabry-Perot intereferometer and a N/O/N diaphragm. The 2 cm length fiber optic Fabry-Perot interferometers in the continuous length of single mode fiber were produced with two pieces of single mode fiber coated with $TiO_{2}$ dielectric film utilizing the fusion splicing technique. The one end of the fiber optic Fabry-Perot interferometer was bonded to a N/O/N diaphragm. and the other end was connected to an optical setup through a 3 dB coupler. For the N/O/N diaphragm sized $2{\times}2\;mm^{2}$ and $8{\times}8\;mm^{2}$, the pressure sensitivity was measured 0.11 rad/kPa and 1.57 rad/kPa, respectively, and both of the nonlinearities were less than 0.2% FS.

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Synthesis of Sludge Waste-derived Semiconductor Grade Uniform Colloidal Silica Nanoparticles and Their CMP Application (슬러지 폐기물을 활용한 반도체급 균일한 콜로이달 실리카 나노입자의 제조 및 CMP 응용)

  • Kim, Dong Hyun;Kim, Jiwon;Jekal, Suk;Kim, Min Jeong;Kim, Ha-Yeong;Kim, Min Sang;Kim, Sang-Chun;Park, Seon-Young;Yoon, Chang-Min
    • Journal of the Korea Organic Resources Recycling Association
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    • v.30 no.3
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    • pp.5-12
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    • 2022
  • This study suggests the effective recycling method of sludge waste from various industrial fields to synthesize uniform colloidal silica nanoparticles. In detail, polymers are removed from the sludge waste to attain sludge-extracted silica (s-SiO2) micron-sized particles, and ammonia assisted sonication is applied to s-SiO2, which has effectively extracted the silanol precursor. The nano-sized silica (n-SiO2) particles are successfully synthesized by a typical sol-gel method using silanol precursor. Also, the yield amounts of n-SiO2 are determined by the function of s-SiO2 etching time. Finally, n-SiO2-based slurry is synthesized for the practical CMP application. As a result, rough-surfaced semiconductor chip is successfully polished by the n-SiO2-based slurry to exhibit the mirror-like clean surface. In this regard, sludge wastes are successfully prepared as valuable semicondutor grade materials.

Characterization of reactive sputtering TaN fate electrode on $HfO_2$ dielectrics ($HfO_2$ dielectrics를 이용한 reactive sputtering TaN gate electrode 의 특성분석)

  • Kim Youngsoon;Lee Taeho;Ahn Jinho
    • Proceedings of the International Microelectronics And Packaging Society Conference
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    • 2003.11a
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    • pp.185-190
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    • 2003
  • 고유전물질인 $HfO_2$ 극박막에 사용될 TaN metal 전극에 대한 특성에 대한 연구를 하였다. 고유전물질인 $HfO_2$는 4" p-type wafer를 SCI cleaning후 ALD(atomic layer deposition)을 통해 $50\AA$를 증착하였다. Ff source는 TEMAH를 이용하였으며 Oxygen source는 $H_2O$를 이용하였다. 이렇게 증착한 $HfO_2$ 극박막에 Ta target을 이용하여 질소 가스를 Ar가스에 첨가하여 reactive sputtering을 통해서 TaN 전극을 증착하였다. TaN 박막의 증착두께는 a--step과 TEM을 통해서 확인하였으며 면저항은 four point probe를 이용하여 측정하였다. 이렇게 증착된 $HfO_2/TaN$구조에 대한 전기적 특성을 측정하였다.

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