NVM characteristics of single-MOSFET cells using nitride spacers with gate-to-drain NOI

This work presents the characteristics of a two-bit-per-cell charge-trapping nonvolatile memory (NVM) device by using gate-to-drain nonoverlapped implanted (NOI) n-MOSFETs. Hot carriers are generated in NOI devices and injected into the silicon nitride spacers. The characteristics of this potential single-transistor NVM cell, including two-bit operation, programming and erasing characteristics, are investigated. Their stability and reliability characteristics such as retention, disturbance and cycling are also evaluated.     

Effect of thermal cycling on the adhesion strength of Sn-9Zn-xAg-Cu interface

The effect of thermal cycling on the adhesion strength of the Sn-9Zn-xAg-Cu interface has been investigated by using pull-off tester, X-ray diffractometer, scanning electron microscope and energy dispersive spectrometer. The Sn-9Zn-xAg lead-free solders offer a better thermal cyclic resistance than the 63Sn-37Pb and Sn-9Zn solder alloys. The adhesion strength of the Sn-9Zn-Cu interface increases from 4.4 /spl plusmn/ 0.4 MPa to 13.8 /spl plusmn/ 0.9 MPa with increasing the thermal cycles from zero to three times but it decreases to 8.5 /spl plusmn/ 0.8 MPa for five cycles. The Sn-9Zn-xAg solder alloys (x=0.5, 2.5, and 3.5 wt%) have a similar tendency and the maximum adhesion strength of 21.41 /spl plusmn/ 1.5 MPa for the Sn-9Zn-2.5Ag solder alloy has been obtained after three thermal cycles. The adhesion strength of the Sn-9Zn-1.5Ag-Cu interface increases from 7.8 /spl plusmn/ 0.6 to 16.6 /spl plusmn/ 0.9 MPa with increasing the thermal cycles from 0 to 5 times.     

Conversion of squid pens to chitosanases and dye adsorbents via Bacillus cereus

Research on Chemical Intermediates - The purpose of this study was to reclaim squid pens for the production of chitosanases and biosorbents of food colorants and industrial dyes via Bacillus cereus...     

Dibromomethane as one-carbon source in organic synthesis: a versatile methodology to prepare the cyclic and acyclic α-methylene or α-keto acid derivatives from the corresponding terminal alkenes

Ozonolysis of mono-substituted alkenes A-1 followed by reacting with a preheated mixture of CH₂Br₂-Et₂NH affords α-substituted acroleins A-2 in good yields. Under very mild reaction conditions, these α-substituted acroleins A-2 can be easily converted to α-methylene esters A-4, which could be further converted to the corresponding α-keto esters A-5. This methodology can be also applied to the preparation of α-methylene lactones B-4, α-methylene lactams, and α-keto lactones B-5 with various ring sizes.     

Kinetics and Mechanisms of Acetylcholinesterase and Butyrylcholinesterase Inhibition by Cardiovascular Drugs and Benzodiazepines

The goal of this work is to determine enzyme kinetics and mechanisms of acetylcholinesterase and butyrylcholinesterase inhibition by five cardiovascular drugs, lovastatin, simvastatin, amlodipine besylate, nifedipine, and hydralazine hydrochloride, and two benzodiazepines, diazepam and chlordiazepoxide hydrochloride. All drugs in this study are reversible mixed‐type inhibitors of acetylcholinesterase and butyrylcholinesterase. The pK_i values for acetylcholinesterase and butyrylcholinesterase inhibition by the cardiovascular drugs are linearly correlated with the molecular weights of the drugs with the slopes of 0.005 and 0.0021, respectively. Therefore, van der Waals' interactions between acetylcholinesterase and the cardiovascular drugs are stronger than those between butyrylcholinesterase and the drugs. This is probably due to a smaller active site gorge and a more significant peripheral anionic substrate binding site of acetylcholinesterase than those of butyrylcholinesterase. The fact that the pK_i values for both butyrylcholinesterase and acetylcholinesterase inhibition by the cardiovascular drugs are linearly correlated with each other suggests that both enzyme inhibition reactions proceed via a common mechanism. Furthermore, amlodipine besylate may be useful in Alzheimer's disease treatment similar to donepezil.     

Enthalpy of formation of aqueous tungstate ion and of crystalline tungstic acid (H2WO4)

Calorimetric measurements of the enthalpy of reaction of WO₃(c) with excess OH^?(aq) have been made at 85°C. Similar measurements have been made with MoO₃(c) at both 85 and 25°C, to permit estimation of ΔH°=?13.4 kcal mol^?1 for the reaction WO₃(c)+2OH^?(aq)=WO^2?₄(aq)+H₂O(liq) at 25°C. Combination of this ΔH° with ΔH°_f for WO₃(c) leads to ΔH°_f=?256.5 kcal mol^?1 for WO^2?₄(aq). We also obtain ΔH°_f=?269.5 kcal mol^?1 for H₂WO₄(c). Both of these values are discussed in relation to several earlier investigations.     

Development of capillary zone electrophoresis-electrospray ionization-mass spectrometry for the determination of lamotrigine in human plasma

A method of coupling capillary zone electrophoresis (CZE) with electrospray ionization-mass spectrometry (ESI-MS) detection has been developed for monitoring an antiepileptic drug, lamotrigine (LTG) in human plasma. The CZE-MS was developed in three stages: (i) CZE separation and ESI-MS detection of LTG and tyramine (TRM, internal standard) were simultaneously optimized by studying the influence of CZE background electrolyte (BGE) pH, BGE ionic strength, and nebulizer pressure of the MS sprayer; (ii) sheath liquid parameters, such as pH, ionic strength, organic modifier content, and flow rate of the sheath liquid, were systematically varied under optimum CZE-MS conditions developed in the first stage; (iii) MS sprayer chamber parameters (drying gas temperature and drying gas flow rate) were varied for the best MS detection of LTG. The developed assay was finally applied for the determination of LTG in plasma samples. The linear range of LTG in plasma sample assay was between 0.1-5.0 microg/mL with a limit of detection as low as 0.05 microg/mL and run time less than 6 min. Finally, the concentration-time profile of LTG in human plasma sample was found to correlate well when CZE-ESI-MS was compared to a more established method of high-performance liquid chromatography with ultraviolet detection.     

Environmentally friendly and efficient: iron-mediated reduction of 3-methyl-5-aryl-1,2,4-oxadiazoles to benzamidines

A new synthetic method is described for the mild and selective reduction of 3-methyl-5-aryl-1,2,4-oxadiazoles to amidines employing iron powder in aqueous medium. Its application is demonstrated in the synthesis of 1, a potent and selective urokinase-type plasminogen activator (uPA) inhibitor.     

Isomerization of n-Hexane over Chlorinated Pt/γ-Al2O3 Catalysts

Chlorided 0.57 wt. % Pt/γ-Al₂O₃ is a moderately active and highly selective catalyst for the isomerization of n-hexane at 300 °C when an excess of H₂ is present. Chlorine, which is continuously lost from the catalyst, may be replaced by adding a small amount of chloroform to the reactant stream. The catalyst exhibits activity and high isomerization selectivity even at 150 °C. Under the conditions of these lower temperature experiments, the equilibrium concentration of C₆ alkenes would be only 8 × 10^?7 Torr. This suggests that the classical mechanism, which involves the formation of n-hexene on the Pt, is not applicable. Rather, it is proposed that isomerization of the alkane occurs at acid sites on the catalyst, and the role of Pt is to catalyze the hydrogenation of any alkenes that might be formed as a result of cracking reactions. At temperatures ≤ 300 °C Brönsted acid sites are present in the catalyst, and presumably are responsible for the isomerization and cracking activity, but at higher temperatures Lewis acid sites play a dominant role.     

Thermoplasticization of wood. II. Cyanoethylation

Cyanoethylation was attempted to convert wood into thermoplastic material as a means to utilize low quality wood species as well as wood waste materials. Cyanoethylation reaction was conducted with control of the alkalinity of the reaction media, reaction temperature and time, and wood-to-acrylonitrile ratio. Cyanoethylated wood was purified and its nitrogen content and weight gain were determined. Fourier transform infrared (FTIR) spectroscopy was used to monitor the absorption peak of cyano group. Thermoproperties of cyanoethylated wood were analyzed by means of a differential scanning calorimeter (DSC) and a dynamic mechanical thermal analyzer (DMTA). Reaction mechanisms and chemistry influencing the thermoproperties of cyanoethylated wood were discussed.