• Electrical & Electronic Materials
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• v.8 no.3
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• pp.261-266
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• 1995

In this study, PZT solutions added impurities of Yttrium acetate were prepared by sol-gel processing and were deposited on Pt/ $SiO_{2}$/Si substrates at 5000 rpm for 20 sec. using spin-coating method. Coated films were annealed at 700-750.deg. C for 30 min. using conventional furnace method. Variations of the crystallographic structure and microstructure of PZT thin films with adding impurities were observed using XRD and SEM, and the electrical properties, such as relative permittivity, tan .delta., hysteresis curves and leakage currents, were measured. As the yttrium contents were increased, the remanent polarization and coercive field were decreased. Variations of remanent polarizations and coercive fields of pure and yttrium doped specimens according to polarization reversal cycles were observed using hysteresis measurement. PZT thin films added $Y^{3+}$ ions were completely crystallized at 750.deg. C. $Y^{3+}$ ions, as donor impurity, substituted Pb.sup 2+/ ions located at A-site of perovskite structure. By substitution of $Y^{3+}$ ions, leakage currents became less by decreasing the space charges. Degradation of remanent polarizations of Yttrium added specimens after fatigue was not observed and coercive fields increased more than those of pure PZT thin films.

• Journal of the Korean Ceramic Society
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• v.41 no.11
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• pp.826-833
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• 2004

In this study, photosensitivity dynamics in SiO$_2$ glass with the composition similar to that of silica Planar Lightwave Circuit (PLC) devices was investigated as a fundamental study prior to the device fabrication. Silica bulk glasses with similar composition to the core layer of PLC devices were prepared with variable composition of B$_2$O$_3$. The photosensitivity in boron and germanium co-doped SiO$_2$ glass yields refractive index change $\Delta$n as high as 10$\^$-3/. However such index modulation disappeared after annealing. From the result of annealing experiment and W absorption / Raman spectra, we conclude the compaction model is applicable to our glass system.

• Nutrition Research and Practice
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• v.8 no.2
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• pp.220-226
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• 2014

BACKGROUND/OBJECTIVES: Arsenic, which causes human carcinogenicity, is ubiquitous in the environment. This study was designed to evaluate modulation of arsenic induced cancer by resveratrol, a phytoalexin found in vegetal dietary sources that has antioxidant and chemopreventive properties, in arsenic trioxide ($As_2O_3$)-induced Male Wistar rats. MATERIALS/METHODS: Adult rats received 3 mg/kg $As_2O_3$ (intravenous injection, iv.) on alternate days for 4 days. Resveratrol (8 mg/kg) was administered (iv.) 1 h before $As_2O_3$ treatment. The plasma and homogenization enzymes associated with oxidative stress of rat kidneys were measured, the kidneys were examined histologically and trace element contents were assessed. RESULTS: Rats treated with $As_2O_3$ had significantly higher oxidative stress and kidney arsenic accumulation; however, pretreatment with resveratrol reversed these changes. In addition, prior to treatment with resveratrol resulted in lower blood urea nitrogen, creatinine and insignificant renal tubular epithelial cell necrosis. Furthermore, the presence of resveratrol preserved the selenium content ($0.805{\pm}0.059{\mu}g/g$) of kidneys in rats treated with $As_2O_3$. However, resveratrol had no effect on zinc level in the kidney relative to $As_2O_3$-treated groups. CONCLUSIONS: Our data show that supplementation with resveratrol alleviated nephrotoxicity by improving antioxidant capacity and arsenic efflux. These findings suggest that resveratrol has the potential to protect against kidney damage in populations exposed to arsenic.

• Journal of the Korean Ceramic Society
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• v.35 no.1
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• pp.97-105
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• 1998

20mol% Gd-doped CeO2 ultrafine powders as a promising electrolyte for the low temperature solid ox-ide fuel cells were synthesized with particle sizes of 15-20 nm using glycine nitrate process(GNP) fol-lowed by sintering their pellets at 150$0^{\circ}C$ for various times in air and then the electrical properties of the sintered pellets were investigated. The sintering behaviors and electrical properties for the sintered 20 sintered mol% Gd-doped CeO2 pellets were analyzed using dilatometer and SEM and AC two-terminal impedance technique respectively. As the heating temperature increased the synthesized powder had the sintering behaviors to show the start of the significant shrink at temperature of about $700^{\circ}C$ and to show the end of the shrink at the temperature of about 147$0^{\circ}C$. When the pellets were sintered with the vaious times at 150$0^{\circ}C$ the temperatuer which the shrink had been already completed the grain sizes in the sintered 20 mol% Gd-doped GeO2 pellets increased with the increase of the sintering time but their electrical resis-tivities showed the minimum value at the sintering time of 10h. It is due that the pellet sintered for 10h had the minimum activation energy fior the electtrical conduction. Thus it is thought that the decrease of the activation energy with the increase of the sintering time to 10h is induced by the enhanced mi-crostructure like the decrease of pore amount and the grain growth and its increase with the sintering times more than 10h is induced by the increase of the amounts of the impurities such as Mg. Al and Si from the sintering atmosphere.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.106-106
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• 1999

반도체 소자가 소브마이크론 이하로 집적화 되어감에 따라, RC 신호 지연 및 간섭 현상, 전력 소비의 증가 문제가 심각하게 대두되고 있다. 이러한 문제를 개선하기 위해서는, 현재 층간 절연막으로 상용화되어 있는 SiO2 박막을 대체할 저유전율 박막의 개발이 필수적이며, 많은 연구자들이 여러 가지 새로운 유기물질과 무기물질은 제안하고 있다. 반도체 공정상의 적합성을 고려할 때, 이들 여러물질 중에서 알킬기를 함유한 SiO2 박막(이하 'Si-O-C-H 박막'으로 표기)에 많은 관심이 집중되고 있다. Si-O-C-H 박막은 알킬기에 의해 형성된 나노 스케일의 기공에 의해 작은 유전율을 가지게 된다. 따라서, 박막내의 알킬기의 함유량이 많을수록 보다 작은 유전율을 얻을 수 있다. 그러나 과다한 알킬기의 함유는 Si-O-C-H 박막의 열적 특성을 열화시키는 부정적인 효과도 있다. 본 연구에서는 bis-trimethylsilylmethane(BTMSM, H9C3-Si-CH2-Si-C3H9) precursor를 이용하여 Si-O-C-H 박막을 증착하였다. BTMSM precursor의 중요한 특징중 하나는, 두 실리콘 원자 사이에 Si-CH2 결합이 존재한다는 사실이다. Si-CH2 결합은 양쪽의 Si에 의해 강하게 결합되어 있어서, BTMSM precursor를 사용하여 Si-O-C-H 박막은 유전상수도 작을 뿐 아니라, 열적으로도 안정된 특성이 얻어질 것으로 기대된다. Si-O-C-H 박막의 열적 안정성을 평가하기 위하여, 고온 열처리 전후의 FT-IR 스펙트럼 분석과 C-V(capacitance-voltage) 측정에 의한 유전상수 변화를 살펴보았다. 또한 증착된 박막의 미세구조 및 step coverage 특성 관찰을 위하여 SEM(scanning electron microscopy) 및 TEM(transmission electron micfroscopy) 분석을 하였다. 변화하였으며 이는 포토루미네슨스의 변화의 원인으로 판단된다. 연구하였다. CeO2 와 Si 사이의 계면을 TEM 측정에 의해 분석하였고, Ce와 O의 화학적 조성비를 RBS에 의해 측정하였다. Si(100) 기판위에 증착된 CeO2 는 $600^{\circ}C$ 낮은 증착률에서 seed layer를 하지 않은 조건에서 CeO2 (200) 방향으로 우선 성장하였으며, Si(111) 기판 위의 CeO2 박막은 40$0^{\circ}C$ 높은 증착률에서 seed layer를 2분이상 한 조건에서 CeO2 (111) 방향으로 우선 성장하였다. TEM 분석에서 CeO2 와 Si 기판사이에서 계면에서 얇은 SiO2층이 형성되었으며, TED 분석은 Si(100) 과 Si(111) 위에 증착한 CeO2 박막이 각각 우선 방향성을 가진 다결정임을 보여주었다. C-V 곡선에서 나타난 Hysteresis는 CeO2 박막과 Si 사이의 결함때문이라고 사료된다.phology 관찰결과 Ge 함량이 높은 박막의 입계가 다결정 Si의 입계에 비해 훨씬 큰 것으로 나타났으며 근 값도 증가하는 것으로 나타났다. 포유동물 세포에 유전자 발현벡터로써 사용할 수 있음으로 post-genomics시대에 다양한 종류의 단백질 기능연구에 맡은 도움이 되리라 기대한다.다양한 기능을 가진 신소재 제조에 있다. 또한 경제적인 측면에서도 고부가 가치의 제품 개발에 따른 새로운 수요 창출과 수익률 향상, 기존의 기능성 안료를 나노(nano)화하여 나노 입자를 제조, 기존의 기능성 안료에 대한 비용 절감 효과등을 유도 할 수 있다. 역시 기술적인 측면에서도 특수소재 개발에 있어 최적의 나노 입자 제어기술 개발 및 나노입자를 기능성 소재로 사용하여 새로운 제품의 제조와 고압 기상 분사기술의 최적화에 의한 기능성 나노 입자 제조 기술을 확립하고 2차 오염 발생원인 유기계 항균제를 무기계 항균제로 대

• The Korean Journal of Air & Space Law and Policy
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• v.7
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• pp.177-203
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• 1995

In den letzten Jahren h ufen sich $F\ddot{a}llen$, in denen Luftpostsendungen gestohlen worden oder sonst abhanden gekommen sind. Zumeist handeltes sich urn Sendungen mit hohem Wert, oft genug urn Sendungen, die erhebliche Geldsummen oder gar Diamanten enthalten. Da nach den luftpostrechtlichen Vorschriften nur recht geringf gige $Betr\ddot{a}ge$ von der Post erstattet werden, liegt der Gedanke nahe, den Luftfrachtf hrer in Anspruch zu nehmen. Bei der $Luftpostbef\ddot{o}rderung$ liegt ein klassisches $Dreiecksverh\ddot{a}ltnis$ vor. Folgende Rechtsbeziehungen sind zu unterscheiden : (1) $Verh\ddot{a}ltnis$ zwischen dem Absender und der Post, (2) $Verh\ddot{a}ltnis$ zwischen Post und $Luftfrachtf\ddot{u}hrer$, (3) $Verh\ddot{a}ltnis$ zwischen $Gesch\ddot{a}digtern$ und $Luftfrachtf\ddot{u}hrer$, wobei der $Gesch\ddot{a}digte$ der Absender, $Empf\ddot{a}nger$ oder dinglich Berechtigte sein kann. Gegenstand der Untersuchung ist dieses zuletzt genannte $Rechtsverh\ddot{a}ltnis$. Angesichts der praktischen Bedeutung der hiermit in Zusammenhang stehenden Fragen, angesichts aber auch der Tatsache, $da{\beta}$ die auf erste Sicht umfangreiche (in - und) $ausl\ddot{a}ndische$ Literatur zuni Luftpostrecht wenig $aussagekr\ddot{a}ftig$ ist, erscheint eine genauere Untersuchung ist folgender: $Zun\ddot{a}chst$ wird die Rechtslage nach dem Warschauer Abkommen, insbesondere die Bestimmung des Art.2 Abs.2 WA, untersucht. $Ber\ddot{u}cksichtigt$ weren sodann die $\ddot{A}nderungen$ der genannten Bestimmung im Haag 1955 und Montreal 1975. Sodann wird die bislang vorliegende internationale Rechtsprechung behandelt. Dem $schlie{\beta}t$ sich die Diskussion des hier $ma{\beta}$- geblichen 52 LuftVG an. Besonderes Gewicht wird hierbei auf die Einbettung des Lufttransportrechts in das allgemeine Transportrecht gelegt. Es erscheint an der Zeit, die Vereinzelung der einzelnen Transportrechtsgebiete zu durchbrechen. Es wird sich zeigen, $da{\beta}$ aus dieser $Ber\ddot{u}cksichtigung$ anderer Transportrechtsgebiete sich eine sachgerechte $L\ddot{o}sung$ entwicklen Das Warschauer Abkommen befa t sich in seinem Art.2 Abs.2 $ausdr\ddot{u}cklich$ mit der Bef rderung von Luftpost. Die $urspr\ddot{u}ngliche$ Fassung von Warschau ist im Haag 1955 $ge\ddot{a}ndert$ worden. Eine weitere $\ddot{A}nderung$ ist in Montreal 1975 beschlossen worden.

• The Korean Society of Law and Medicine
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• v.10 no.2
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• pp.253-286
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• 2009

Die $\ddot{a}$mrztliche Behandlung des Patienten durch den Arzt geschieht im Rahmen eines Rechtsverh$\ddot{a}$ltnisses. Das Arzt-Patienten-Rechtsverh$\ddot{a}$ltnis stellt regelm$\ddot{a}$ssig der Arztvertrag oder Behandlungsvertrag dar. Arzt und Patient schliessen einen Arztvertrag ab. Grunds$\ddot{a}$tzlich verbindet der Arztvertrag die Partner pers$\ddot{o}$nlich. Aber minderj$\ddot{a}$hrige Patienten sind gesch$\ddot{a}$ftsunf$\ddot{a}$hig oder in der Gesch$\ddot{a}$ftsf$\ddot{a}$higkeit beschr$\ddot{a}$nkt. Minderj$\ddot{a}$hrige Patienten verm$\ddot{o}$gen also allein grunds$\ddot{a}$tzlich keine wirksamen Willenserkl$\ddot{a}$rungen abzugeben und somit keine wirksamen Arztvertr$\ddot{a}$ge zu schliessen. Arztvertr$\ddot{a}$ge von minderj$\ddot{a}$hrigen Patienten sind nur bei Einwilligung der gesetzlichen Vertreter wirksam. Vom Abschluss des Arztvertrags ist deutlich die Einwilligung zur Behandlung zu unterscheiden. Die Einwilligung ist kein Rechtsgesch$\ddot{a}$ft. Die Einwilligung durch die Eltern erfolgt nur solange der minderj$\ddot{a}$hrige Patient nicht reif genug ist, die Entscheidung selbst zu treffen. Jugendlicher Patient ist z.B. in der Lage, die Einwilligung selbst zu geben, sofern er Wesen, Bedeutung und Tragweite der Behandlung zu verstehen vermag. Der Vorschriften des KBGB zur Gesch$\ddot{a}$ftsf$\ddot{u}$hrung ohne Auftrag gelten, wenn der Arzt einen Bewusstlosen versorgt. Nach $\S$734 KBGB erfolgt die Gesch$\ddot{a}$ftsf$\ddot{u}$hrung ohne Auftrag dann zu Recht, wenn sie dem Interesse und dem wirklichen oder mutmasslichen Willen des Patienten entspricht. Der Patient kann aus einem Ausland stammen. F$\ddot{u}$r ausl$\ddot{a}$ndische Patienten gilt generell das koreanische Recht. Grunds$\ddot{a}$tzlich sollte man einen des Koreanischen nicht m$\ddot{a}$chtigen Ausl$\ddot{a}$nder nach M$\ddot{o}$glichkeit in seiner Sprache aufkl$\ddot{a}$ren und dann den Arztvertrag abschliessen. Aufgrund der Privatautonomie kann jeder Patient frei entscheiden, ob, mit wem und wor$\ddot{u}$ber er einen Arztvertrag abschliesst. Deswegen ist auch der Wille des Anh$\ddot{a}$ngers vom Sekten und abweichenden Lebensauffassung grunds$\ddot{a}$tzlich zu ber$\ddot{u}$cksichtigen. Zum Beispiel handelt der Zeuge Jehovas auf eigene Gefahr, wenn er eine notwendige Behandlung ablehnt. Aber die Freiheit, eine gebotene Behandlung abzulehnen, kann in Konflikt mit dem Schutz des minderj$\ddot{a}$hrigen Patienten gelangen. Sobald die sektiererische oder abweichende Haltung droht, einen minderj$\ddot{a}$hrigen Patienten zu gef$\ddot{a}$hrden, hat das elterliche Sorgerecht einzuschr$\ddot{a}$nken.

• Nuclear Engineering and Technology
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• v.55 no.3
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• pp.1061-1070
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• 2023

Over the last few years, lead-free inorganic metal perovskites have gained impressive ground in empowering satellites in space exploration owing to their material stability and performance evolution under extreme space environments. The present work has examined the versatility of eight such perovskites as space radiation shielding materials by computing their photon, charged particles and neutron interaction parameters. Photon interaction parameters were calculated for a wide energy range using PAGEX software. The ranges of heavy charged particles (H, He, C, N, O, Ne, Mg, Si and Fe ions) in these perovskites were estimated using SRIM software in the energy range 1 keV-10 GeV, and that of electrons was computed using ESTAR NIST software in the energy range 0.01 MeV-1 GeV. Further, the macroscopic fast neutron removal cross-sections were also calculated to estimate the neutron shielding efficiencies. The examined shielding parameters of the perovskites varied depending on the radiation type and energy. Among the selected perovskites, Cs₂TiI₆ and Ba₂AgIO₆ displayed superior photon attenuation properties. A 3.5 cm thick Ba₂AgIO₆-based shield could reduce the incident radiation intensity to half its initial value, a thickness even lesser than that of Pb-glass. Besides, CsSnBr₃ and La_0.8Ca_0.2Ni_0.5Ti_0.5O₃ displayed the highest and lowest range values, respectively, for all heavy charged particles. Ba₂AgIO₆ showed electron stopping power (on par with Kovar) better than that of other examined materials. Interestingly, La_0.8Ca_0.2Ni_0.5Ti_0.5O₃ demonstrated neutron removal cross-section values greater than that of standard neutron shielding materials - aluminium and polyethylene. On the whole, the present study not only demonstrates the employment prospects of eco-friendly perovskites for shielding space radiations but also suggests future prospects for research in this direction.

• Transactions on Electrical and Electronic Materials
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• v.13 no.4
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• pp.171-176
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• 2012

As langasite $A_3BC_3D_2O_{14}$ compounds with piezoelectric properties exhibit no phase transition up to the melting point of 1,400-$1,500^{\circ}C$, many high temperature applications are expected for the SAW filter, temperature sensor, pressure sensor, and so on, based on the digital transformation of wider bandwidth and higher-bit rates. It has a larger electromechanical coupling factor compared to quartz and also nearly the same temperature stability as quartz. The $La_3Ga_5SiO_{14}$ (LGS) crystal with the $Ca_3Ga_2Ge_4O_{14}$-type crystal structure was synthesized and the crystal structure was analyzed by Mill et al. It is also an important feature that the growth of the single crystal is easy. In the case of three-element compounds such as $[R_3]_A[Ga]_B[Ga_3]_C[GaSi]_DO_{14}$ (R=La, Pr and Nd), the piezoelectric constant increases with the ionic radius of R. In this study, crystal structures of four-element compounds such as $[A_3]_A[B]_B[Ga_3]_C[Si_2]_DO_{14}$ (A = Ca or Sr, B = Ta or Nb) are analyzed by a single crystal X-ray diffraction, and the mechanism and properties of the piezoelectricity depending on the species of cation was clarified based on the crystal structure.

• Polymer(Korea)
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• v.32 no.3
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• pp.239-245
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• 2008

Block copolymers of the general formula $[(-CO-R'-CO-HN-Ar-NH-CO-R'-CO)_xNH(CH_2)_3-(Me_2SiO)_y(CH_2)_3NH_2]_n$, [n=18.00 to 1175.0] where $R'=CH_2CH(CH_2GeCl_3)$;$CH_2CHGeCl_3CH_2$; and $Ar=-C_6H_4$;$-(o.CH_3C_6H_4)_2$;$-o.CH_3OC_6H_4)_2$;$-(o.CH_3C_6H_4)$ were prepared by a polycondensation reaction of polyamide containing a pendant trichlorogermyl group and terminal acid chloride $Cl(-CO-R'-CO-NH-Ar-NH-CO-R'-CO-)_xCl$ with aminopropyl-terminated polydimethylsiloxane $H_2N(CH_2)_3(Me_2SiO)_y-(CH_2)_3NH_2]$, (PDMS). These polymers were characterized by elemental analysis, $T_g$, FT-IR, $^1H$-NMR, solid state $^{13}C$-NMR, and molecular weight determination. The thermal stability of these copolymers was examined using thermal analysis techniques, such as TGA and DSC. Their molecular weights as determined by laser light scattering technique ranged $5.13{\times}10^5$ to $331{\times}10^5\;g/mol$. These polymers display their $T_g$ in the range of 337 to $393^{\circ}C$ with an average decomposition temperature at $582^{\circ}C$.