• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.1
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• pp.33-38
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• 2017

In this paper, a 4-channel common-cathode VCSEL diode driver array with 3.125 Gb/s per channel operation speed is realized. In order to achieve faster speed of the switching main driver with relatively large transistors, the transmitter array chip consists of a pre-amplifier with active inductor stage and also an input buffer with modified equalizer, which leads to bandwidth extension and reduced current consumption. The utilized VCSEL diode provides inherently 2.2 V forward bias voltage, $50{\Omega}$ resistance, and 850 fF capacitance. In addition, the main driver based upon current steering technique is designed, so that two individual current sources can provide bias currents of 3.0 mA and modulation currents of 3.3 mA to VCSEL diodes. The proposed 4-channel VCSEL driver array has been implemented by using a $0.11-{\mu}m$ CMOS technology, and the chip core occupies the area of $0.15{\times}0.18{\mu}m^2$ and dissipates 22.3 mW per channel.

• Bulletin of the Korean Chemical Society
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• v.23 no.9
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• pp.1229-1258
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• 2002

This paper reports the photochemical reduction of benzil 1 to benzoin 2 and the reduction of 2 to hydrobenzoin 4 in deoxygenated solvents in the presence of triethylamine (TEA) and/or TiO2. Without TEA or TiO2, the photolysis of 1 resulted in very low yield of 2. The presence of TEA or TiO2 increased the rate of disappearance of 1 and the yield of 2, which were further increased considerably by the presence of water. The photoreduction of 1 to 2 proceeds through an electron transfer to 1 from TEA or hole-scavenged excited TiO2 followed by protonation. In the reaction medium of 88 : 7 : 2 : 3 CH3CN/CH3OH/H2O/TEA with 2.5 $㎎/m{\ell}$ of TiO2, the yield of 2 was as high as 85 % at 50 % conversion of 1. The photolysis of 2 in homogeneous media resulted in photo-cleavage to benzoyl and hydroxybenzyl radicals, which are mostly converted to benzaldehyde. The reduction product 4 is formed in low yield through the dimerization of hydroxybenzyl radicals. The addition of TEA increased the conversion rate of 2 and the yield of 4 significantly. This was attributed to the scavenging effect of TEA for benzoyl radical to produce N,N-diethylbenzamide and the photoreduction of benzaldehyde in the presence of TEA. The ratio of $(\pm)$ and meso isomers of 4 obtained from the photochemical reaction is about 1.1. This ratio is the same as that from the photochemical reduction of benzaldehyde in the presence of TEA. In the TiO2-sensitized photochemical reduction of 2, meso-4 was obtained in moderate yield. The reduction of 2 to 4 proceeds through two consecutive electron/proton transfer processes on the surface of the photocatalyst without involvement of ${\alpha}-cleavage$. The radical 11 initially formed from 2 by one electron/proton process can also combine with hydroxy methyl radical, which is generated after hole trapping of excited TiO2 by methanol, to produce 1,2-diphenylpropenone after dehydration reaction.

• Korean Journal of Veterinary Research
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• v.48 no.3
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• pp.251-258
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• 2008

The neurotoxicity of C-terminal fragments of amyloid precusor protein (CT) is known to play some roles in Alzheimer's disease progression. In this study, we investigated the effects of the recombinant C-terminal 105 amino acid fragment of amyloid precusor protein (CT105) on cholinergic function using CT105-injected rat. To study the effects of CT105 on septohippocampal pathway, choline acetyltransferase (ChAT) positive neurons were examined in the medial septum and in the diagonal band after an injection of CT105 peptide into the lateral ventricle. Immunohistological analysis revealed that the number of ChAT-immunopositive cells decreased significantly in both medial septum and diagonal band. In addition, CT105 decreased ChAT-immunopositive cells in the hippocampal area, particulary in the dentate gyros. To study the effect of amyloid beta peptide ($A{\beta}$) and CT105 on the cholinergic system, each peptide was injected into the left lateral ventricle, and acetylcholine (ACh) levels were monitored in hippocampus. ACh level in the hippocampal area was reduced to 60% of control level in $A{\beta}$-treated group, and the level was reduced to 15% of control level in CT105-treated group, at one week after the injection. ACh level was further reduced to 35% of control in $A{\beta}$-treated group, whereas the level was slightly increased to 30% of control in CT105-treated group at 4 weeks after the injection. Taken together, the results in the present study suggest that CT105 impairs the septohippocampal pathway by reducing acetylcholine synthesis and release, which results in damage of learning and memory.

• Mycobiology
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• v.37 no.1
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• pp.28-30
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• 2009

This study was aimed at evaluating the growth promoting effect of symbiotic algal polyol (ribitol) and plant hormones on the lichen-forming fungi (LFF), Ramalina farinacea (CH050010 and 40403) and Ramalina fastigiata. The addition of ribitol to basal (malt-yeast extract) medium enhanced the relative growth rates of all three LFF. R. farinacea (CH050010), R. farinacea (40403) and R. fastigiata (H06127) showed 35.3%, 29.0% and 29.3% higher growth rates, respectively, compared to the control. IBA (indole-3-butyric acid) and TIBA (2,3,5-tridobenzoic acid) also increased growth rates of the LFF by 34 to 64% and 7 to 28%, respectively, compared to the control. The combination of ribitol with IBA or TIBA synergistically increased the growth of all LFF. For example, ribitol and IBA treatments increased growth rates of R. farinacea (CH050010), R. farinacea (40403) and R. fastigiata (H06127) by 79.4%, 40.3% and 72.8% in, respectively, compared to those grown on the basal medium. The stimulating effect of ribitol and IBA on the LFF growth induced vertical development of the fungal mass in culture. We suggest that lichen-forming fungal growth of Ramalina lichens can be stimulated aposymbiotically by supplementing polyols and plant hormones to the basal medium in the mass production of lichen secondary metabolites under large scale culture conditions.

• Korean Journal of Pharmacognosy
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• v.40 no.2
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• pp.128-136
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• 2009

This study was carried out to investigate the antidiabetic and antioxidative effect of Lycii fructus in the Streptozotocin(STZ)-induced diabetic rats. The effective fractions were prepared as a form of organic solvents of $CH_{3}(CH_{2})_{4}CH_{3}$ $CHCI_{3}$, EtOAc, BuOH and $H_{2}O$ fractions prepared from the EtOH extract of Lycii fructus and The diabetes were induced by an tail-intravenous injection of STZ with a dose of 45 mg/kg dissolved in citrate buffer. The various fractions of Lycii fructus were orally administrated once a day for 7 days. The contents of serum glucose, and triglyceride in the $CHCI_{3}$ fraction and hepatic lipid peroxidation in the EtOAc, BuOH and $H_{2}O$ fractions treated rats were significantly decreased when compared to those of the STZ-control group In addition, an activity of hepatic GST in the BuOH fraction treated rats was significantly increased compared to that of the STZ-control group. whereas, activities of hepatic catalase, GSH-Px in the BuOH fraction treated rats were significantly decreased compared to those of the STZ-control group. Meanwhile, The content of hepatic glycogen and avtivity of hepatic glucokinase in $CHCI_{3}$ fraction treated rats were significantly increased, but activity of glucose-6-pase was significantly decreased in the $CHCI_{3}$ fraction treated rats. In conclusion, these results indicated that the BuOH fraction of Lycii fructus was effective for the antioxidation, and also the $CHCI_{3}$ fraction of Lycii fructus was effective for the antidiabetes in the STZ-induced diabetic rats.

• Journal of the Korean Society for Library and Information Science
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• v.29
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• pp.345-382
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• 1995

The type printing of first Ch'ing dynasty term in China is worthy to be studied because the type printing during that period included metal type, wood type, and clay type as well as the development phase was similar to Chosun dynasty culturally and technologically. This paper studied typography during the first Ch'ing dynasty term, including Shunzhi(1662-1722), Yongaheng(1723-1735), Qianlong(1736-1795), Jiaqing(1796­1820) period. The main results of the study is as follows. 1. The main body of type printing was bookstore, lecture-hall, and individual as well as the royal court that is the central government. 2. The content of type edition covers classics, history, philosophy, and literary works. Specifically, even though Wuyingdienjuzhenban series is excluded, the content includs study of the classics, class of the history, class of the philosophy, literature works that include collection works and novel and government official bulletin. 3. The printing technique of bronze type was very popular In Beijing. Jiangsu, and Taiwan. It's scale and production technique was more elaborate than in Ming dynasty. 4. Wood type was very popular in Beijing, Jiangsu, Zhejiang, Anhui, Sichuan, and Fujian. In addition to wood type, chinese ware type was applied to book printing in Shandong. However, most of them were wood type and they were used after Qianlong period. 5. The production technique of type was skilled enough to present the fine view of a style of type. The typesetting technique was improved as much as woodblock printing. With regard to the making technology of Chinese ink, the light and darkness of chinese ink was not even sometimes. But, the technology was improved significantly when comparing with the failure experience of printing that chinese ink was not developed in early type invention. 6. In case that the book was printed in bookstore with the intention of profit and the number of book was large, the proofreading attitude was rough. However, overally, it was made correction carefully applying the various methods of proofreading. 7. The support of government made a great contribution in the area of all printing technology, including production, typesetting, and brushing of type.

• Bulletin of the Korean Chemical Society
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• v.23 no.12
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• pp.1754-1758
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• 2002

Tetrathiafulvalene(TTF) reacts with $PdCl_2,Pd(NO_3)_2$ and $Pd(hfacac)_2$(hexafluoroacetylacetonate) in ethanol to give $(TTF)_{1.5}PdCl_2$ (1a), $(TTF)_3Pd(NO_3)_2$ (1b) and $(TTF)_4Pd(hfacas)_2$ nd (1c), respectively. $PdCl(TCNQ)_{2.5}{\cdot}CH_3OH(2a)$was obtained from the reaction of $PdCl_2$ with LiTCNQ in methanol via the partial replacement of $Cl^-$ in $PdCl_2$ by $TCNQ^-$anion, whereas the total substitution of the labile $NO_3^-$ in $Pd(NO_3)_2$ yielded pd(TCNQ)·$CH_3OH$ (2b). $Pd(hfacac)_2(TCNQ)_2\cdot3CH_3OH$ (2c) was obtained from $Pd(hfacac)_2$ and LiTCNQ in methanol. The prepared compounds were characterized by spectroscopic (IR, UV, XPS) methods and magnetic (EPR, magnetic susceptibility) studies. The powdered electrical conductivities (${\sigma}_{rt}$) of the prepared compounds at room temperature were about~$10^{-7}S{\cdot}cm^{-1}$. The effective magnetic moments were lass than the spin-only value of one unpaired electron and no EPR signals from Pd metal ions were observed in any of the compounds, indicating that the Pd ions were diamagnetic and the magnetic moments arose from$(TTF)_n$ or $(TCNQ)_n$ moieties. The experimental evidences revealed that the charge transfer had occurred form $(TTF)_n$ moiety to the central Pd metal ion in 1a, 1b and 1c. Thus the TTF donors were ions in 2a and 2b were diamagnetic Pd(II) oxidation state. In contrast, the Pd metal ion was oxidized to Pd(IV) state in 2c as a result of an addition of $TCNQ^-$anion to $Pd(hfacac)_2$ in methanol. The oxidation states of the Pd metal ions were confirmed using the x-ray photoelectron spectroscopy.

• Journal of the Korean Chemical Society
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• v.23 no.4
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• pp.237-242
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• 1979

The equivalent conductances of sodium, potassium, ammonium, tetramethylammonium, triethylammonium, diethylammonium and ethylammonium iodide, and picrate salts of sodium and potassium in ethylene carbonate have been measured at 40.0 $^{\circ}C. The limiting equivalent conductances of the salts have been computed by Fuoss-Onsager-Skinner equation. The limiting ionic equivalent conductances of $Na^+,\;K^+,\;and\;NH^+$ are in order of $Na^+ which is the reverse order of solvation for the ions in any solution, And the order of limiting ionic equivalent conductances for alkylammonium ions is $(C_2H_5)_4N^+<(C_2H_5)_3NH^+<(CH_3)_4N^+<(C_2H_5)_2NH_2^+<(C_2H_5)NH_3^+$ which coincides with the order of mass transfer. From the dissociation constants of the saltss determinde by Fuoss-Kraus method, it is found that ethyene carbonate is a good ionizing solvent for the salts. In addition, Stokes radii and effective fadii of ions have been calculated by Stokes law and Nightingale method, repectively. From the results, it appears tha alkylammonium ions and picrate ion seem to be not solvated, and tha iodide ion is fairly solvated in ethylene carbonate.

• Journal of the Korean Ceramic Society
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• v.54 no.4
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• pp.303-307
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• 2017

Pure $In_2O_3$, 0.5 and 1.0 wt% Mg doped $In_2O_3$ hollow spheres were synthesized by ultrasonic spray pyrolysis of a solution containing In-, Mg-nitrate and sucrose and their gas sensing characteristics to 5 ppm $C_2H_5OH$, p-xylene, toluene, and HCHO were measured at 250, 300 and $350^{\circ}C$. Although the addition of Mg decreases the specific surface area and the volume of meso-pores, the gas response (resistance ratio) of the 0.5 wt% Mg doped $In_2O_3$ hollow spheres to 5 ppm $C_2H_5OH$ at $350^{\circ}C$ (69.4) was significantly higher than that of the pure $In_2O_3$ hollow spheres (24.4). In addition, the Mg doped $In_2O_3$ hollow spheres showed the highest selectivity to $C_2H_5OH$. This was attributed to the dehydrogenation of $C_2H_5OH$ assisted by basic MgO into reactive $CH_3CHO$ and $H_2$.

• Journal of the Korean Chemical Society
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• v.36 no.2
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• pp.318-323
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• 1992

Following seven new nucleophilic adducts of sulfilimine compounds were prepared by the addition of 1-methyl-5-mercapto-1,2,3,4-tetrazole to vinylsulfilimine derivatives; S-Phenyl-S-2-(1-methyl-1,2,3,4-tetrazole-5-thio)-ethyl-N-p-tosylsulfilimine, S-p-tolyl-S-2-(1-methyl-1,2,3,4-tetrazole-5-thio)-ethyl-N-p-tosylsulfilimine, S-m-tolyl-S-2-(1-methyl-1,2,3,4-tetrazole-5-thio)-ethyl-N-p-tosylsulfilimine, S-p-chlorophenyl-S-2-(1-methyl-1,2,3,4-tetrazole-5-thio)-ethyl-N-p-tosylsulfilimine, S-p-bromophenyl-S-2-(1-methyl-1,2,3,4-tetrazole-5-thio)-ethyl-N-p-tosylsulfilimine, S-p-methoxyphenyl-S-2-(1-methyl-1,2,3,4-tetrazole-5-thio)-ethyl-N-p-tosylsulfilimine and S-p-nitrophenyl-S-2-(1-methyl-1,2,3,4-tetrazole-5-thio)-ethyl-N-p-tosylsulfilimine. The structures of these adducts were confirmed by elemental analyses, MP, UV, IR-and NMR-Spectra.