A new testing acceleration chip for low-cost memory tests

It is argued that the development of semiconductor memories has reached a turning point. In the multimegabit dynamic random access memories (DRAMs) of the future, major factors contributing to the chip cost are process complexity, die size, equipment cost, and test cost. If conventional test methods are used, test costs will grow at an especially rapid rate. A memory test concept called the testing acceleration chip, which could reduce future test costs a hundredfold and yet maintain AC testing reliability, is presented     

Induction, localization, and purification of a novel sialidase, deaminoneuraminidase (KDNase), from Sphingobacterium multivorum

Recently, we reported the discovery of a new type of sialidase, KDNase, which specifically hydrolyzes the ketosidic linkages of 2-keto-3-deoxy-D-glycero-D-galacto-nononic acid (KDN), but not N-acylneuraminyl linkages. We now report that this enzyme, designated KDNase SM, is an inducible enzyme that is localized in the periplasm of Sphingobacterium multivorum. Growth of S. multivorum in the presence of KDN-containing oligosaccharide alditols, KDNalpha2-->3Galbeta1-->3GalNAc alpha1-->3[KDNalpha2--> (8KDN alpha2-->)n-->6]GalNAcol, as a sole carbon source induced KDNase SM activity 15 40-fold, compared with growth in the absence of inducer. KDN, Neu5Ac, or Neu5Ac oligomers were ineffective as inducers. The enzyme was released from the periplasm of induced cells by cold osmotic shock and purified 700-fold to homogeneity. The specific activity of the pure enzyme was 82,100 units/mg of protein. KDNase SM activity resided in a single polypeptide chain with an estimated molecular weight of approximately 47,500. Enzyme activity was maximal at near neutral pH. The availability of pure KDNase will now make it possible to study the structure and functional role of KDN-glycoconjugates and to determine the molecular mechanism whereby the enzyme can discriminate between KDN and N-acylneuraminic acid.     

A case of meningioma with non-accumulation of 99mTc-ECD and increased accumulation of 99mTc-HMPAO in the tumor]

99mTc-ECD SPECT and 99mTc-HMPAO SPECT with or without Matas test were performed in a 62-year-old woman with meningioma in the left anterior cranial fossa. After injection of 740 MBq 99mTc-ECD or HMPAO, 64 projection images were collected with a rotating Gamma camera. Matas test was carried out by compressing the left common carotid artery for about one minute immediately after RI injection. Although 99mTc-ECD SPECT showed non-accumulation in the tumor, 99mTc-HMPAO SPECT demonstrated increased accumulation in it. This area of increased accumulation disappeared on 99mTc-HMPAO SPECT with Matas test which causes decrease in blood flow of the tumor. These findings suggest 99mTc-ECD and 99mTc-HMPAO have a different mechanisms of accumulation in the meningioma.     

A method for the prediction of hot-carrier lifetime in floating SOINMOSFETs

A concept was presented for the prediction of the device lifetimes for the hot-carrier effect (hot-carrier lifetimes) in floating SOI MOSFETs. The concept is that hot-carrier lifetimes in floating SOI MOSFETs can be predicted by estimating the hole current. In order to verify the validity of this concept, the hole current was investigated using device simulation. The results showed that the ratio of the hole current to the drain current in a floating-body SOI MOSFET is approximately equal to the ratio of substrate current to drain current in a body-tied one. Based on this fact, a method for accurately predicting the hot-carrier lifetime in floating-body SOI MOSFETs was proposed. The hot-carrier lifetime predicted with this method agreed well with the experimental results. This study showed that only the drain current difference between floating and body-tied structures results in lifetime differences, and there is no special effect on hot-carrier degradation in floating SOI MOSFETs. In this prediction, therefore, floating SOI MOSFETs can be treated in the same way as bulk MOSFETs. Hot-carrier lifetimes in floating SOI MOSFETs can be predicted using the hole current, while substrate currents are used in bulk MOSFETs     

Study on Preparation and Property of Poly－Aminosilicone－Rare Earth Composite

The poly-aminosilicone-rare earth composite was prepared by poly-aminosilicone cross-linked with rare earth and active silanol. The thermal stability of the composites was studied by thermogravimetric analysis (TG). Force condition of the composites in electric field was analyzed and relative polarizability was derived. It is found that the composites containing different rare earth ions have different relative polarizability. The experiment results reveal that organosilicon materials with different electrical performance can be obtained by this way. Meanwhile, the absorption and flourescene spectrum of composites were also investigated. Compared to rare earth chloride, the spectrum properties of the composite are changed obviously. The possible reasons for these phenomena were discussed.     

Temperature Dependence of Electrical and Thermal Conductivities of an Epoxy-Based Isotropic Conductive Adhesive

The temperature dependence of the transport properties, including electrical and thermal conductivities, of a practical isotropic conductive adhesive (ICA) including an epoxy-based binder was investigated in order to comprehensively evaluate the physical changes induced during exposure to elevated temperatures. The ICA specimens were cured and post-annealed under various conditions in order to clarify the effect of curing state of the adhesive binder on the electrical resistivity. The electrical resistivity at ambient temperature tends to decrease with increasing curing temperature, even if the samples exhibit full conversion. In addition, an annealing effect, resulting in a deviation from a linear relationship in the temperature dependence of resistivity, can be induced during the heating process experienced during resistivity measurements. However, the ICA specimens exhibited similar values for the temperature coefficient of resistivity (TCR), regardless of the curing and post-annealing conditions in the temperature range where the annealing effect is rarely induced, although the thermal history of the specimens significantly influences the absolute values of electrical resistivity. The temperature dependence of the thermal conductivity is almost accounted for by the decrease in the contribution of conducting electrons in the temperature range below the glass-transition temperature, T _g.     

High efficiency ester condensation using hydrophobic zeolite membranes

We successfully developed zeolite membranes with hydrophilic character, by choosing appropriate zeolites in terms of hydrophilicity and high acid tolerance. We evaluated thus developed membranes by their pervaporation (PV) performance, dehydration from acidic organic solvent. The zeolite membranes we developed, based on merlinoite (MER), chabazite (CHA) or phillipsite (PHI), are shown to exhibit stable dehydration performance, respectively. We successfully applied the membranes to the selective removal of water in an ester condensation reaction starting from a stoichiometric mixture of a carboxylic acid and an alcohol. The availability of pervaporation-assisted ester condensation reaction was validated by various kinds of combinations of carboxylic acid and alcohols, which implies the general availability of pervaporation-assisted process intensification by zeolite membranes. This paper was presented at the 11th Korea-Japan Symposium on Catatysis held at Seoul, Korea, May 21–24, 2007.     

Synthesis and characterization of binary chromophore polymers for electro-optic application

We prepared the side-chain electro-optic polymers by the active bonding of cyanate- and hydroxy-functional groups, and employed these side-chain polymers as hosts for the bi-chromophore system to enhance the electro-optic coefficient (r₃₃). In singular chromophore polymer (in PMMA host), the dependence of EO response on loading concentration was examined, r₃₃ about 26 pm/V was obtained. In order to further incorporate the chromophore, the loading behavior in binary chromphore systems was investigated. The optimal r₃₃ more than 40 pm/V was achieved, which was almost the sum of two individual polymers. Furthermore, the temporal stability at room temperature and 85 °C, respectively, over 500 h was evaluated for the potential application on electro-optic devices.     

Copolymerization of diphenylmethane andp-xylene by oxidative coupling

Summary Diphenylmethane underwent oxidative coupling in the presence of di-t-butyl peroxide and formed 1,1,2,2-tetraphenylethane. This coupling reaction resulted in the formation of a copolymer of diphenylmethane andp-xylene. The new copolymer was soluble in common organic solvents and had a molecular weight of 32,000 (polystyrene base).On leave from Cosmo Oil Co., Japan, under a contract with the Japan International Cooperation Agency