Numerical Simulation of Single-Electron Tunneling in Random Arrays of Small Tunnel Junctions Formed by Percolation of Conductive Nanoparticles

We numerically simulated electrical properties, i.e., the resistance and Coulomb blockade threshold, of randomly-placed conductive nanoparticles. In simulation, tunnel junctions were assumed to be formed between neighboring particle-particle and particle-electrode connections. On a plane of triangle 100×100 grids, three electrodes, the drain, source, and gate, were defined. After random placements of conductive particles, the connection between the drain and source electrodes were evaluated with keeping the gate electrode disconnected. The resistance was obtained by use of a SPICE-like simulator, whereas the Coulomb blockade threshold was determined from the current-voltage characteristics simulated using a Monte-Carlo simulator. Strong linear correlation between the resistance and threshold voltage was confirmed, which agreed with results for uniform one-dimensional arrays

Effects of nuclear orientation on fusion and fission in the reaction using 238U target nucleus

Fission fragment mass distributions in the reaction of 30Si+238U were measured around the Coulomb barrier. At the above-barrier energies, the mass distribution showed a Gaussian shape. At the subbarrier energies, triple-humped distribution was observed, which consists of symmetric fission and asymmetric fission peaked at AL/AH ~ 90/178. The asymmetric fission should be attributed to quasifission from the results of the measured evaporation residue (ER) cross-sections for 30Si+238U. The cross-section for 263Sg at the abovebarrier energy agree with the statistical model calculation which assumes that the measured fission cross-section originates from fusion-fission, whereas the one for 264 Sg measured at the sub-barrier energy is smaller than the calculation, which suggests the presence of quasifission

Tunic Cell Morphology and Classification in Botryllid Ascidians(Morphology)

The morphology of tunic cells was investigated in ten botryllid ascidians, six Botryllus and four Botrylloides species, by means of light and electron microscopy. Three types of tunic cells were described, I.e. amoeboid, vacuo-granular and large granule tunic cells. Amoeboid tunic cells were irregularly shaped, and had many pseudopodia. They were found in the all species studied here. Vacuo-granular tunic cell had many vacuoles which contained round granules, and was found in four Botryllus and four Botrylloides species. The diameters of the granules varied amond species (ca. 1.4-0.8 ^m). Large granule tunic cells were peculiar to Botryllus scalaris, and each of them contained a single large granule with lamellate substructure. Some tunic cells showed intermediate characteristics of amoeboid and vacuo-granular tunic cells. It seems that amoeboid tunic cells probably differentiate into vacuo-granular tunic cells in the tunic. There are thread-like bacteria in the tunic, and they often dangle around vacuo-granular tunic cells. There may be some interactions between tunic cells and the bacteria

13C-NMR Spectroscopic Study on Chemical Species in Piperazine−Amine−CO2−H2O System before and after Heating

AbstractChemical reactions associated with the absorption of CO2 into aqueous solutions of blends of piperazine (PZ) with N- methyldiethanolamine (MDEA), etc. were studied by 13C-NMR spectroscopy. The coexistence of PZ and MDEA enhanced the initial apparent rate of HCO3−/CO2−3 formation. This result can be explained by considering that PZ−monocarbamate rapidly formed works as an organocatalyst in the formation reaction of HCO−3. Concentration changes of chemical species in CO2-absorbed aqueous amine solutions upon heating (80°C, 30min) were studied by 13C-NMR spectroscopy. Carbon dioxide regeneration originates mainly from HCO3−/CO3, and not form carbamate and carbonate

Strong and Specific Recognition of CAG/CTG Repeat DNA (5'-dWGCWGCW-3') by a Cyclic Pyrrole-Imidazole Polyamide

Abnormally expanded CAG/CTG repeat DNA sequences lead to a variety of neurological diseases, such as Huntington's disease. Here, we synthesized a cyclic pyrrole-imidazole polyamide (cPIP), which can bind to the minor groove of the CAG/CTG DNA sequence. The double-stranded DNA melting temperature (Tm ) and surface plasmon resonance assays revealed the high binding affinity of the cPIP. In addition, next-generation sequencing showed that the cPIP had high specificity for its target DNA sequence

One-dimensional array of small tunnel junctions fabricated using 30-nm-diameter gold nanoparticles placed in a 140-nm-wide resist groove

We present percolative arrays of gold nanoparticles (NPs) formed in a resist groove. To enhance the con nection probability, the width of the resist groove (140 nm) was designed to be approximately five times larger than the diameter of gold NPs (30 nm). Two-stage deposition of gold NPs was employed to form bridge connections between the source and drain electrodes. Dithiol molecules coated on surfaces of gold NPs worked as tunnel barriers. 5 of 12 samples exhibited Coulomb blockade characteristics, in one of which the gate response was confirmed