Four porous crystalline coordination polymers with two-dimensional frameworks of a double-edged axe-shaped motif, {[Co(NCS)2(3-pia)2] ⋅2 EtOH⋅11 H2O}n (1 a), {[Co(NCS)2(3-pia)2]⋅4 Me2CO}n (3 {[Co(NCS)2(3-pia)2]⋅4T HF}n b) and {[Co(NCS)2(3-pna)2]n} (5), have been synthesized by the reaction cobalt(II) thiocyanate N-(3-pyridyl)isonicotinamide (3-pia) or N-(3-pyridyl)nicotinamide (3-pna). X-ray crystallographic characterization reveals that adjacent layers are stacked such channels created,...

Drain current collapse in AlGaN/GaN HEMTs has been studied systematically by applying bias stress to the device. The was suppressed light illumination with energy smaller than bandgap. position dependence of and measurement series source drain resistances revealed that caused surface states between gate electrodes, which captured electrons injected from gate. eliminated passivation device Si/sub 3/N/sub 4/ film.

Abstract Amines, particularly polyamines, catalyzed the polycondensation of silicic acid in water. The resultant gel contained these polyamines with a N/Si molar ratio up to 0.5. IR and powder X-ray studies showed that silica are hybridized at molecular level through hydrogen bonding. adsorbed anionic dyes from water, whereas normal adsorbs cationic dyes. Induced CD was observed for indigo carmine on gel–poly(l-lysine) hybrid, showing hybrid provides chiral environment adsorbate.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMultifunctional and Chiral Porphyrins: Model Receptors for RecognitionHisanobu Ogoshi Tadashi MizutaniView Author Information Department of Synthetic Chemistry Biological Chemistry, Graduate School Engineering, Kyoto University, Sakyo-ku, 606-01, Japan Cite this: Acc. Chem. Res. 1998, 31, 2, 81–89Publication Date (Web):January 7, 1998Publication History Received6 June 1997Published online7 January 1998Published inissue 1 February...

AlGaN/GaN HEMTs with a thin InGaN cap layer have been proposed to implement the normally off HEMTs. The key idea is employ polarization-induced field in layer, by which conduction band raised, leads operation. fabricated HEMT an In <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.2</sub> Ga xmlns:xlink="http://www.w3.org/1999/xlink">0.8</sub> N thickness of 5 nm showed operation threshold voltage 0.4 V and maximum transconductance 85 mS/mm for...

We have investigated the relation between conduction property and work function of contact metal in carbon nanotube field-effect transistors (NTFETs). The type drain current are dependent on function. In contrast to NTFETs with Ti Pd electrodes, which showed p-type behaviour, devices Mg electrodes ambipolar characteristics most Ca n-type behaviour. This indicates that barrier height metal/nanotube is metal, suggests Fermi-level pinning weak at interface, conventional semiconductors such as...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDesign and Synthesis of a Trifunctional Chiral Porphyrin with C2 Symmetry as Recognition Host for Amino Acid EstersTadashi Mizutani, Tadashi Ema, Takashi Tomita, Yasuhisa Kuroda, Hisanobu OgoshiCite this: J. Am. Chem. Soc. 1994, 116, 10, 4240–4250Publication Date (Print):May 1, 1994Publication History Published online1 May 2002Published inissue 1 1994https://pubs.acs.org/doi/10.1021/ja00089a013https://doi.org/10.1021/ja00089a013research-articleACS...

The packet-like space-charge behaviour in an oxidized crosslinked polyethylene (XLPE) film doped with antioxidant is discussed through computer simulation. model based on the following assumptions, (1) both electrons and holes are injected from electrodes they migrate to opposite by hopping transport, (2) also supplied acceptor sites depending field, (3) excited level only via intermediate level. In this model, a packet not caused excess of mobile but deficiency holes. ionized acceptors left...

Transport properties of C60 fullerene peapods and Gd@C82 metallofullerene are investigated by using the field effect in a gated structure. The results show that exhibit unipolar p-type characteristics, whereas ambipolar both p- n-type characteristics. This difference transport behavior can be explained terms bandgap narrowing peapods. One important findings is tunable electronic achieved different types encapsulated molecules.

The MOBILE is a logic gate exploiting the monostable-bistable transition of circuit that consists two resonant tunneling transistors connected in series. It has several advantages including multiple inputs and functions. This paper describes output characteristics multiple-input MOBILE's discusses their applications. For two-input MOBILE, it demonstrated both NAND NOR operations are possible with appropriate control voltage. implies possibility variable function gate. Furthermore, threshold...

A systematic study of the binding carbohydrates by functionalized zinc porphyrins indicated that [5, 15-bis(8-quinolyl)porphyrinato]zinc(II) (1) showed marked affinity for octyl glucoside and mannoside in CHCl3 (−ΔG° = 4.5−6.3 kcal mol-1). Analysis complexation-induced shifts carbohydrate OH protons 1H NMR revealed receptor 1 bound 4-OH group coordination to 6-OH 3-OH groups hydrogen bonding quinolyl nitrogen atoms. These results comparison with reference receptors ligands recognized...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTRecognition of .alpha.-amino acid esters by zinc porphyrin derivatives via coordination and hydrogen bonding interactions. Evidence for two-point fixation from thermodynamic induced circular dichroism spectroscopic studiesTadashi Mizutani, Tadashi Ema, Takashi Yoshida, Yasuhisa Kuroda, Hisanobu OgoshiCite this: Inorg. Chem. 1993, 32, 10, 2072–2077Publication Date (Print):May 1, 1993Publication History Published online1 May 2002Published inissue 1...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTArtificial receptors for amino acids in water. Local environmental effect on polar recognition by 6A-amino-6B-carboxy- and 6B-amino-6A-carboxy-.beta.-cyclodextrinsIwao. Tabushi, Yasuhisa. Kuroda, Tadashi. MizutaniCite this: J. Am. Chem. Soc. 1986, 108, 15, 4514–4518Publication Date (Print):July 1, 1986Publication History Published online1 May 2002Published inissue 1 July...

We study the phenomenon of change in carrier type carbon nanotube field-effect transistors (CNFETs) caused by atomic layer deposition (ALD) a HfO(2) gate insulator. When is deposited on CNFET, changes from p-type to n-type. The so-obtained n-type device has good performance and stability air. conductivity such with channel length 0.7 microm 11% quantum conductance 4e(2)/h. contact resistance for electron current estimated be 14 kOmega. conduction this CNFET maintained more than 100 days....

Peroxidase activity of a myoglobin reconstituted with chemically modified heme 1 is reported. The bearing total eight carboxylates bound to the terminal propionate side chains incorporated into apomyoglobin from horse heart obtain new myoglobin, rMb(1), unique binding domain structure. UV−vis, CD, and NMR spectra rMb(1) are comparable those native nMb. mixing hydrogen peroxide yields peroxidase compound II-like species, rMb(1)-II, since spectrum rMb(1)-II identical that observed for...

In our efforts toward the development of enzyme-like catalysts for regioselective functionalization unprotected sugars, DMAP-catalyzed acetylation carbohydrates in chloroform was investigated. Product distributions monoacetylated sugars were determined under kinetic control. To accurately evaluate relative reactivity each OH group, reaction conditions used which only obtained and almost no diacetylated formed as by-products. Systematic experiments glucose, mannose, galactose revealed...

The functional operation of the MOBILE (monostable-bistable transition logic element) has been studied using multiple-input gates. uses two resonant-tunneling transistors (RTTs) connected in series and driven by an oscillating bias voltage to produce a mono-to-bistable circuit. A having three input gates with 1:2:4 width ratio can distinguish all 8 (2/sup 3/) patterns corresponding each weighted sum, depending on threshold value selected control gate. results confirm realization sum...

A new GaAs MESFET structure with n+-implanted layers and a self-aligned gate has been developed by dielectric lift-off technology trilevel resist. The electrical characteristics are improved greatly resistance reduction outside the channel under gate. 280 mS/mm transconductance 39.5 ps/gate propagation delay have obtained.

A series of water-soluble porphyrin receptors having a hydrophobic binding pocket, Lewis acidic site (Zn), and an electrostatic recognition (COO- groups) were prepared. All the have [meso-tetrakis(p-carboxyphenyl)porphyrinato]zinc (Zn·TCPP) as common structural unit, eight ω-carboxyalkyloxy groups (alkyloxy = methoxy (1), butoxy (2), decyloxy (3)) at ortho positions phenyl groups. These bind amines, α-amino acid esters, oligopeptides in water with significant selectivity. For hydrophilic...

Zinc porphyrin receptors bearing 12 ester groups in the meso phenyl (1−3) were prepared, and binding of amines α-amino esters was studied with emphasis on mechanisms. The X-ray crystallographic analysis 5,10,15,20-tetrakis(2,6-bis(carbomethoxymethoxy)-4-carbomethoxyphenyl)porphyrin (free base 1) showed that receptor has a pocket above plane. UV−visible titration experiments revealed zinc bound constants (Ka) ranging from 0.5 to 52 700 M-1 CH2Cl2 at 25 °C. functional 1 assisted aromatic (Ka =...

High-frequency measurements of the 1.3-μm-long gate AlGaN-GaN HEMTs have been performed at temperatures ranging from 23 to 187/spl deg/C. The cutoff frequency f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> decreased with increasing temperature. It was 13.7 and 8.7 GHz deg/C, respectively. effective electron velocities /spl upsi//sub eff/ in channel evaluated total delay time versus I/sub D/-inverse relation were 1.2 0.8×10/sup 7/ cm/s