Anisotropic Magnetization and Charge Density Wave in a Na0.78CoO2 Single Crystal

이종수,J. B. Peng,S. M. Lee,C. T. Lin 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.2

Single crystals of γ-Na0.78CoO2 were grown using the floating zone method. The static magnetic susceptibility M/H(T) of Na0.78CoO2 showed significant anisotropic behavior for different crystal orientations of H ∥ (ab) and H ∥ (c). While (M/H)ab(T) for a magnetic field H= 1 T in an ab-plane followed the Curie-Weiss law at high temperatures (T ≥ 100 K), (M/H)c(T) for H ∥ c-axis deviated from Curie-Weiss behavior, which may be understood by using phonon localization from strong electron-phonon coupling. The impurity spin-1/2 effect, dressed by spin fluctuation, was significant at low temperatures (T ≤ 30 K) for both field orientations of H ∥ (ab) and H ∥ (c). The electrical resistivity ρ(T) of Na0.78CoO2 showed a clear metallic character down to 16 K, with a weak increase in the resistivity ρ(T) at low temperatures T ≤ 16 K). The gap-like behavior of ρ(T) was insensitive to applied magnetic fields up to 7 T, which indicates a non-degenerate charge gap. The electrical conductivity σ(T) followed the density wave behavior with a small energy gap (0.64 meV) at low temperatures. We discussed the electrical resistivity ρ(T)$ and the anisotropic M/H(T) behavior of Na0.78CoO2 in terms of the charge density wave and a strong electron-phonon interaction. Single crystals of γ-Na0.78CoO2 were grown using the floating zone method. The static magnetic susceptibility M/H(T) of Na0.78CoO2 showed significant anisotropic behavior for different crystal orientations of H ∥ (ab) and H ∥ (c). While (M/H)ab(T) for a magnetic field H= 1 T in an ab-plane followed the Curie-Weiss law at high temperatures (T ≥ 100 K), (M/H)c(T) for H ∥ c-axis deviated from Curie-Weiss behavior, which may be understood by using phonon localization from strong electron-phonon coupling. The impurity spin-1/2 effect, dressed by spin fluctuation, was significant at low temperatures (T ≤ 30 K) for both field orientations of H ∥ (ab) and H ∥ (c). The electrical resistivity ρ(T) of Na0.78CoO2 showed a clear metallic character down to 16 K, with a weak increase in the resistivity ρ(T) at low temperatures T ≤ 16 K). The gap-like behavior of ρ(T) was insensitive to applied magnetic fields up to 7 T, which indicates a non-degenerate charge gap. The electrical conductivity σ(T) followed the density wave behavior with a small energy gap (0.64 meV) at low temperatures. We discussed the electrical resistivity ρ(T)$ and the anisotropic M/H(T) behavior of Na0.78CoO2 in terms of the charge density wave and a strong electron-phonon interaction.

Distribution of stress state in the Nankai subduction zone, southwest Japan and a comparison with Japan Trench

Lin, W.,Byrne, T.B.,Kinoshita, M.,McNeill, L.C.,Chang, C.,Lewis, J.C.,Yamamoto, Y.,Saffer, D.M.,Casey Moore, J.,Wu, H.Y.,Tsuji, T.,Yamada, Y.,Conin, M.,Saito, S.,Ito, T.,Tobin, H.J.,Kimura, G.,Kanagaw Elsevier Scientific Publishing Co 2016 Tectonophysics Vol.692 No.2

<P>To better understand the distribution of three dimensional stress states in the Nankai subduction zone, southwest Japan, we review various stress-related investigations carried out in the first and second stage expeditions of the Nankai Trough Seismogenic Zone Experiment (NanTroSEIZE) by the Integrated Ocean Drilling Program (IODP) and compile the stress data. Overall, the maximum principal stress sigma(l) in the shallower levels (<similar to 1 km) is vertical from near the center of forearc basin to near the trench and; the maximum horizontal stress S-Hmax (interpreted to be the intermediate principal stress sigma(2)) is generally parallel to the plate convergence vector. The exception to this generalization occurs along the shelf edge of the Nankai margin where S-Hmax, is along strike rather than parallel to the plate convergence vector. Reorientation of the principal stresses at deeper levels (e.g., >similar to 1 km below seafloor or in underlying accretionary prism) with sigma(1) becoming horizontal is also suggested at all deeper drilling sites. We also make a comparison of the stress state in the hanging wall of the frontal plate-interface between Site C0066 in the Nankai and Site C0019 in the Japan Trench subduction zone drilled after the 2011 Mw 9.0 Tohoku-Oki earthquake. In the Japan Trench, a comparison between stress state before and after the 2011 mega-earthquake shows that the stress changed from compression before the earthquake to extension after the earthquake. As a result of the comparison between the Nankai Trough and Japan Trench, a similar current stress state with trench parallel extension was recognized at both C0006 and C0019 sites. Hypothetically, this may indicate that in Nankai Trough it is still in an early stage of the interseismic cycle of a great earthquake which occurs on the decollement and propagates to the toe (around site C0006). (C) 2015 Elsevier B.V. All rights reserved.</P>

Studies on Filariasis in Kinmen (Quemoy) Islands, Republic of China

Fan,P.C.,Wang,Y.C.,Liu,J.C.,Lo,H.S.,Hsu,Y.P.,Yen,C.H.,Lin,C.C.,Hsu,S.T. INSTITUTE OF TROPICAL MEDICINE YONSEI UNIVERSITY 1974 YONSEI REPORTS ON TROPICAL MEDICINE Vol.5 No.1

1972年 7月 1日부터 1973年 6月 30日까지 1年間 中華民國 臺?省 金門鳥에서 絲狀 症에 關한 調査硏究를 實施한 바 다음과 같은 結果를 얻었다. 1. 金門鳥 55村落에 居住하는 20,018 住民을 對象으로 調査한 바 血中 microfilariae (mf.) 兩性率은 8.8%였고 血液 20立方mm當 mf농도는 16.2였으며 絲狀 感染으로 因 臨床例 는 19.2%였다. 金門鳥 駐屯 軍人 2,428名에서 mf.양성율은 0.1%, mf. 감염농도는 20立方mm當 26.3이었으며 臨床例는 없었다. mf.感染濃度 및 臨床例에 있어 확실히 女性보다는 男性에서 高率을 보였으나 mf.陽性率은 兩性間에 差異가 없었다. mf.陽性率과 臨床例는 年齡의 增加와 一致하였으나 mf. 감렴농도는 年齡의 증가와 無關하였다. 2. 金文鳥 駐屯 軍人에 있어 주둔 其間과 絲狀 感染과는 關係가 없었으며 駐屯基地와 村落과의 距離와도 無關하였다. 軍人들은 모기에 물리지 않도록 잘 保護되어 있었고 주둔지역은 完全히 住民들과 격리되어 있었다. 3. 51村落으로부터의 血液檢査를 받은 1,470名의 絲狀 感染陽性者 中에서 臨床病勢르 보인 例는 19.2%였으며 女性보다는 男性에서 約 5倍가 많았다. 男性에 있어서의 大部分의 臨床例는 生殖器에 症狀을 보였는데 其中 10%는 象皮症을 가진 例는 2名뿐이었다. 4. 43村落의 家屋內에서 잡힌 모기는 4屬 14種(Culex 10種, Aedes 2種, Anopheles 1種, Armigeres 1種)이었으며 이들中 Cules P. fatigans와 Armigeres subalbatus가 大部分이었으나 其他 12種은 매우 적었다. Culcx mimesticus, C. (L) vorax, C. fuscocephala 및 Acdes nocturnus등 의 4新種은 처음으로 發見되었다. Culex p.fatigans는 現存「반크롭트」 絲狀 만을 옮기는 媒介昆 으로 알려져 있다. 治療前 8個 村落으로부터 잡은 438마리의 Culex p. fatigans에서 幼 을 內包하고 있는 모기는 1마리 平均 5.9마리의 絲狀 幼 을 갖고 있는 셈이었으며 全體 感染率은 11.9%, 感染期 幼 을 가진 모기는 10.5%이었다. 上記 8個 村落 住民을 治癒한 後의 樣狀은 治療前과 아주 달라서 모기 1마리當 平均 2.1마리의 幼 을 갖고 있었고 全體感染率은 2.2%, 感染期幼 內包率은 0.09%였다. 平均 pH가 7.4(6.4∼8.0)인 8個處의 모기 産卵場所에서 잡힌 모기 幼 은 모두 11種이었다. 有機燐劑의 一種인 Sumithion을 1平方m當 0.2gm의 농도로 모기 産卵場所 水面에 撒布하였던바 모든 모기 幼 에 對한 殺 果가 좋았다. 5. 總 1.590名의 絲狀 感染者에게 成人當 總量 5gm의 diethylcarbamazine을 10∼12日 間 服用시켜 보았다. 治療率은 80.6%, mf. 減少率은 96.9%였고 反應率는 67.2%였다. 여러 가지 副作用은 있었으나 一般的으로 輕微하였으며 患者가 참을 수 있었으므로 最高用量으로 投藥했을 경우에도 大部分 거절 하지 않았다. 8個 部落에서 捕獲된 Culex P. fatigans의 絲狀 幼 全體感染率, 感染期幼 內包率 및 感染濃度는 患者治療前에 各各 11.9%, 10.5%, 5.9였는데 治療後에는 2.2%, 0.09%, 2.1로 떨어져서 diethylcarbamazine은 microfilariae에 對한 殺충효果가 높을 뿐 아니라 絲狀충 만延을 組止시키는데 좋은 藥劑라고 思料된다 The present investigation is a serial study on “Filariasis in Kinmen (Quemoy) Islands”, which was performed from July 1, 1972 to June 30, 1973. The results are summarized as follows; 1. Parasitological investigation: Of 20,018 Kinmen Chinese in 55 villages examined, the microfilariae (mf.) rate of 8.8%, mf. density of 16.2 per 20cmm blood and clinical rate 19.2% were found: the corresponding figures for a total of 2,428 military personnel were 0.1%, 29.3 and 0.0% respectively. The mf. density and clinical rate were obviously higher in the males than in the females, but no difference was found for the microfilarial rate. The mf. rate and clinical rate were correspondingly increased with age, but there was no difference in mf. density. 2. Transmission of filariasis: It seems no any relation to the length of stationing of the Chinese troops on Kinmen Islands, and also no relation to the distance between the villages and camps; because the servicemen are well protected from the mosquito bites and bites and the camps are completely isolated, to and off limit to the villagers, though they have common places of entertainment. 3. Clinical investigation: Of 1,470 filarial carriers in 51 villages examined physically, the clinical rate of 19.2% was detected. It was about 5 times higher in males than in females. In the males, most of the cases the trouble in their reproductive organs, and 10% had elephantiasis; but in the females, the lymph nodes enlargement and chyluria were more common, only 2 cases had elephantiasis. The clinical rates increased corresponding with age. 4. Entomological investigation: Fourteen(14) species of 4 genera (10 Culex, 2 Aedes, 1 Anopheles and 1 Armigeres) of household mosquitoes were collected from indoor resting sites of 43 villages on kinmen Islands, in which, Cules P. fatigans and Armigeres subalbatus were the most common species, but the remaining 12 species are faily rare. Four (4) new species: Culex mimeticus, C. (L) vorax, C, fucocephala and Aedes noturnvs were found for the first time. Culex p.fatigans is still the only vector. in transmission of bancroftian filariasis. The infection rate of 11.9%, infective rate of 10.5% and 5.9 filarial larvae per infected mosquito were detected in 438 Culex p. fatigans from 8 villages before treatment. The corresponding figures were much lower in the above same villages after treatment (2.2%, 0.09% and 2.1). Eleven (11) species of moswquito larvae were collected from 8 kinds of breeding sites; where, the pH value of 7.4(ranged 6.4∼8.0) was measured. “Sumithion”is one of the organophosphorous compounds, which was first used on the water surface with the dosage of 0.2gm per square meter.A high insecticidal effect against different species of mosquito larvae was observed. 5. Chemotherapy of filariasis: Of 1.590 filarial carriers scheme, with a total does of 5 gm of diethylcarbamazine per adult case for a period of 10∼12 days schedule was performed. The cure rate of 80.6%, mf. reduction tate of 96.9% and reaction rate of 67.2% were found. Although many kinds of side effects were encountered, they were usually mild or transient and could be tolerated by the patients, thus there was almost no refused to the administration of the drug even if the drug was increased to the maximum dosage. The natural infection rate, infective rate and filarial larval density of Culex P. fatigans in 8 villages were found much higher before control measure (11.9%, 10.5% and 5.9%) than after control (2.2%, 0.09% and 2.1). It showed that diethylcarbamazine is a powerful microfilaricidal drug in eliminating the filarial infection and reducing this transmission.

Effects of catalysts on structural and adsorptive properties of iron oxide-silica nanocomposites

Cătălin Ianăși,Paula Ianăși (b. Svera),Adina Negrea,Mihaela Ciopec,Oleksandr I. Ivankov,Alexander I. Kuklin,László Almásy,Ana-Maria Putz 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.2

Iron oxide-silica nanocomposites were prepared by sol-gel method using ammonia (NH3), acetic acid (CH3COOH) and hydrochloric acid (HCl) catalysts to generate different pH values for the reaction conditions. As starting precursors, for the silica, respectively, for the iron oxide, tetraethylorthosilicate (TEOS) and iron-III-acetylacetonate were used. The physico-chemical characterization of the materials revealed that the sample obtained with HCl catalyst displays the largest surface area (300m2/g), the most compact network structure, highest surface roughness, biggest crystallite size (14 nm), magnetization (7 emu/g) and superparamagnetic behavior. These materials were tested for adsorption of Cr6+ and Zn2+ from aqueous solution. Sample M-HCl presented the highest surface area and was further used for adsorption of metal ions. Kinetic, thermodynamic and equilibrium adsorption measurements studies were made for Cr6+ and Zn2+. To establish the material behavior from a thermodynamic point of view, temperature and contact time of adsorption process, activation energy, free energy, of standard enthalpy and entropy were calculated. The kinetic behavior was modelled by pseudo-first-order, pseudo-second-order and intraparticle diffusion kinetic models and the adsorption characteristics were determined by modelling the experimental data with Langmuir, Freundlich and Sips isotherms.

Removal of cadmium from aqueous solutions using inorganic porous nanocomposites

Cătălin Ianăşi,Mirela Picioruş,Roxana Nicola,Mihaela Ciopec,Adina Negrea,Daniel Nižňanský,Adél Len,László Almásy,Ana-Maria Putz 한국화학공학회 2019 Korean Journal of Chemical Engineering Vol.36 No.5

The present paper reports a one-pot synthesis of magnetic nanocomposites samples through acid catalyzed sol-gel method. Fe(III) acetylacetonate was used as precursor of the iron oxide phase: tetraethylortosilicate for the silica phase and polyvinyl alcohol (PVA, molecular mass 49000) as pore former. Different concentrations of Fe2O3 in composites matrices were prepared and studied ranging from 0% to 20%. All reactions took place in one pot at room temperature; the materials were subsequently heat treated at 300 oC, to ensure the crystallinity for the iron oxide having spinel structure, forming nanoparticles confined in the silica matrix. The materials were characterized using X-ray diffraction, small-angle neutron scattering, FT-IR spectroscopy, nitrogen adsorption, Mössbauer spectroscopy and magnetization measurements. The maximum value of room temperature saturation magnetization of ~54 emu/g and 0.11 kOe coercive field was achieved for the magnetic nanocomposite sample with 20% Fe2O3. The highest surface area of 680m2/g was obtained for the sample with 10% Fe2O3. The potential applicability of the obtained materials was studied for adsorption performance for cadmium in aqueous solutions. The Langmuir isotherm model described well the adsorption data, indicating monolayer adsorption of Cd(II) on the heterogeneous composite surface.

E-Beam Processing of Collagen-Poly(N-vinyl-2-pyrrolidone) Double-Network Superabsorbent Hydrogels: Structural and Rheological Investigations

Maria Demeter,Ion Călina,Cătălin Vancea,Murat Şen,Mădălina Georgiana Albu Kaya,Elena Mănăilă,Marius Dumitru,Viorica Meltzer 한국고분자학회 2019 Macromolecular Research Vol.27 No.3

Collagen (C)-poly(N-vinyl-2-pyrrolidone) (PVP) double-network superabsorbent hydrogels were synthesized by e-beam (electron beam) radiation processing, both with the addition of water-soluble cross-linking agents (CA), as well as without CA. The aim of the study was to develop a hydrogel for future application as wound dressings via e-beam radiation cross-linking of two biocompatible polymers. The formation of C-PVP hydrogels was confirmed by Fourier transform infrared (FTIR) spectroscopy and their performance was determined from morphological and rheological experiments, such as sol-gel analysis, swelling capacity, storage (G') and viscous (G'') moduli, cross-linking density, and pore size. Sol-gel analysis was performed in order to determine the gel properties as function of absorbed dose and it was found that the degradation density (p0)/cross-linking density (q0) ratio indicates a negligible contribution of chain scission processes. The rheological data confirmed that the elastic properties were predominant: G' moduli were larger than G'' moduli, as is specific to elastic solids and indicate the formation of a permanent hydrogel network were cross-links are present. Moreover, the swelling studies indicated that the hydrogels have good stability both in deionized water and phosphate-buffered saline (PBS) solution at 37 oC, and superabsorbent properties. The hydrogels network parameters obtained with lower content of CA, could be controlled by changing the absorbed dose.

Studies on Morphological Characteristics of Korean Taenia saginata taiwanensis from Korea(Cheju Strain)

Chung, W.C.,Lin, C.Y.,Fan, P.C.,Soh, C.T. INSTITUTE OF TROPICAL MEDICINE YONSEI UNIVERSITY 1993 YONSEI REPORTS ON TROPICAL MEDICINE Vol.24 No.1

The present report is of an extensive investigation on the morphology of the adult and cysticercus stages of Korea Taenia (Cheju strain). The data on the adult worm are based on seven worms (two with scolex and five without) obtained from three infected persons. The worms weighed an average of 19.3gm (12∼30gm) and averaged 432cm (303∼665cm) long with 760 (640∼954) proglottides. The scolices averaged 458㎛ (440∼457㎛)×805㎛ (785∼825㎛), sucker 326㎛ (310∼341㎛)×236㎛ (230×242㎛), and rostellum 109㎛ (108∼110㎛)×110㎛ (108∼110㎛). In the mature proglottid, there were 832 (640∼1,034) testes which covered the whole dorsal side of the proglottid except for behind the vitellaria. The two ovaries averaged 430㎛ (250∼610㎛)×301㎛ (175∼550㎛) on the left and 418㎛ (260∼630㎛)×296㎛ (175∼485㎛) on the right. The vitellariae averaged 589㎛ (410∼840㎛)×138㎛ (75∼185㎛) and the mehlis gland 93㎛ (75∼110㎛) in diameter. The cirrus pouch did not extent to the excretory vessel and the vagina had a sphincter. In the gravid proglottid, there were 18 (13∼24) uterine branches, 2 (0∼5) buds, and 59 (23∼102) twigs present on the left side. Those on the right side averaged 18 (13∼24), 2 (0∼5), and 61 (35∼101), respectively. The length, width and thickness of the inner shell (embryophore) of the fixed eggs were 32㎛ (26∼36㎛), 26㎛ (20∼30㎛), and 1.2㎛ (1∼2㎛), respectively. The oncospheres averaged 20㎛ (13∼24㎛)×16㎛ (12∼19㎛); all had six hooks. The corresponding figures for the unfixed or fresh eggs were 35㎛ (28∼51㎛), 29㎛ (24∼43㎛), 2㎛ (1∼3㎛), 27㎛ (20∼35㎛)×22㎛ (18∼28㎛) and 6 hooks, respectively. There were an average of 58,847 (31,540∼89,300) eggs in a gravid proglottid. The length, width and diameters of the protoscolex, rostellum, and suckers of the cysticerci were 1.6mm(0.4∼3.4㎛), 1.5mm (0.3∼3mm), 501㎛ (150∼1,528㎛), 89㎛ (4∼240㎛), and 192㎛ (90∼380㎛), respectively. There were two rows of rudimentary hooklets on the scolex of the cysticerci. The inner hooklets averaged 16 (1∼76) in number and 11㎛ (2∼28㎛) in length. The outer hooklets were numerous and appeared as small dots. The surface of the cysticerci had a tubercular appearanc. These biological and morphological characteristics of Korean Taenia are similar to other T. saginata-like tapeworms in Asia, and have been designated as a new subspecies T. saginata taiwanensis.

Pulse-controlled generation and characterization of partially-switched multiple-value polarization states in PZT ceramics

Dan Ricinschi,Damian Nicastro,Cătălin Harnagea,Masanori Okuyama 한국물리학회 2012 Current Applied Physics Vol.12 No.3

This paper explores in depth the partially switched states of ferroelectrics, through macroscopic polarization measurements in conjunction with piezoresponse force microscopy, x-ray diffraction and dielectric characterization, with the ultimate purpose to explore their usefulness for unconventional multiple-value nonvolatile memory applications. We prove that it is possible to reproducibly generate analog levels of polarization in a Pb(Zr,Ti)O3 ferroelectric ceramic capacitor and control them with electric pulses that stabilize unique domain patterns, compatible with those of adjacent states. Some of these states contain, in the same locations of the sample surface, areas with orientation of polarization vector opposite to that of the electric field that decides the analog polarization level, while others contain clamped domain structures with reduced piezoelectric activity. We argue that disclosing the complex relationships between the domain structures of the analog polarization states, as well as their dependence on write voltage parameters, might help to expand the multiple-value storage capability of ferroelectrics beyond what would be achievable on macroscopic scale.

Activation of Akt as a mechanism for tumor immune evasion.

Noh, Kyung Hee,Kang, Tae Heung,Kim, Jin Hee,Pai, Sara I,Lin, Ken Y,Hung, Chien-Fu,Wu, T-C,Kim, Tae Woo Academic Press 2009 Molecular therapy Vol.17 No.3

<P>Immune evasion is an important reason why the immune system cannot control tumor growth. To elucidate the mechanism for tumor immune evasion, we generated an immune-resistant human papillomavirus type 16 (HPV-16) E7-expressing tumor cell line by subjecting a susceptible tumor cell line to multiple rounds of in vivo immune selection with an E7-specific vaccine. Comparison of parental and immune-resistant tumors revealed that Akt is highly activated in the immune-resistant tumors. Retroviral transfer of a constitutively active form of Akt into the parental tumor significantly increased its resistance against E7-specific CD8(+) T-cell mediated apoptosis. The observed resistance against apoptosis was found to be associated with the upregulation of antiapoptotic molecules. We also observed that intratumoral injection of an Akt inhibitor enhanced the therapeutic efficacy of E7-specific vaccine or E7-specific CD8(+) T-cell adoptive transfer against the immune-resistant tumors. Thus, our data indicate that the activation of PI3K/Akt pathway represents a new mechanism of immune escape and has important implications for the development of a novel strategy in cancer immunotherapy against immune-resistant tumor cells.</P>

Applications of Laser-Fabricated Plasma Structures in Laser-Wakefield Accelerators, X-ray Lasers and Plasma Nonlinear Optics

C.T. Hsieh,M.W. Lin,C.L. Chang,Y.C. Ho,S.Y. Chen,J. Wang,M.C. Chou,J.Y. Lin,C.H. Pai,P.H. Lin,L.C. Tai,S.H. Chen,G.Y. Tsaur,C.C. Kuo,T.Y. Chien 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.6

A general method for fabricating transient plasma structures with high-intensity laser pulses is developed to gain fine control over laser-plasma interactions. These structures have been used as programmable photonic devices in the development of laser-wakefield accelerators, soft X-ray lasers and plasma nonlinear optics driven by multi-terawatt laser pulses. Plasma ramps are used to control electron injection in laser-wakefield accelerators, plasma waveguides are used to enhance the efficiency of soft X-ray lasers by orders of magnitude and periodic plasma structures are used to achieve quasi-phase matching in relativistic harmonic generation. By scanning the interaction length with the same plasma-fabrication method, tomographic measurements are carried out to resolve the injection/acceleration process in laser-wakefield accelerators and amplification processes in X-ray lasers and relativistic harmonic generation. A theoretical analysis and a computer simulation are also carried out to provide insightful pictures of these processes. These research works show that by controlling plasma structures with optical fabrication methods, laser-plasma interaction can be engineered to expand and enrich the frontier of high-field physics.