Sparse coding for layered neural networks

We investigate storage capacity of two types of fully connected layered neural networks with sparse coding when binary patterns are embedded into the networks by a Hebbian learning rule. One of them is a layered network, in which a transfer function of even layers is different from that of odd layers. The other is a layered network with intra-layer connections, in which the transfer function of inter-layer is different from that of intra-layer, and inter-layered neurons and intra-layered neurons are updated alternately. We derive recursion relations for order parameters by means of the signal-to-noise ratio method, and then apply the self-control threshold method proposed by Dominguez and Bollé to both layered networks with monotonic transfer functions. We find that a critical value _C of storage capacity is about 0.11|a ln a|⁻¹ (a1) for both layered networks, where a is a neuronal activity. It turns out that the basin of attraction is larger for both layered networks when the self-control threshold method is applied.     

New approach to C-aryl glycosides starting from phenol and glycosyl fluoride. Lewis acid-catalyzed rearrangement of O-glycoside to C-glycoside

C-Glycosidation of phenols is achieved by treatment of glycosyl fluoride with phenolic compound under Lewis acidic conditions, which leads to initial O-glycoside formation followed by rearrangement to C-congener. Cp₂HfCl₂-AgClO₄ is particularly effective for this conversion.     

X-ray and pulsed NMR studies of lithium nitride chlorides in anti-fluorite type structures

Lithium nitride chloride, Li_2-2xN_0.5-xCl_0.5+x′ have been found to possess anti-fluorite type structures in the range 0.05 <x< 0.1, with Fm3m, and with the lattice parameter in the range 5.354 ≈ 5.375 Å. The ⁷Li relaxation was studied in the temperature range 178–625 K, and the activation energy for Li⁺ hopping motion, E_a = 0.19 eV was obtained for x = 1. Small variation of E_a with composition or with occupancy of the Li⁺ site was confirmed.     

Total synthesis of marchantin A,a novel cytotoxic bis(bibenzyl) isolated from liverworts

Total synthesis of marchantin A, a novel cytotoxic bis(bibenzyl) isolated from some liverworts, has been accomplished in 12 steps.     

Self-threading of a poly(ethylene glycol) chain in a cyclodextrin-ring: control of the exchange dynamics by chain length

Poly(ethylene glycol) (PEG)-substituted cyclodextrins (CDs) with different chain lengths have been synthesized. PEG-substituted CDs formed self-threading complexes in aqueous solutions, and the conformational exchange dynamics between self-threading and dethreading could be regulated by its chain length.     

Measurement of flame temperature by optical fiber thermometer

The characteristics of an optical fiber thermometer (OFT) having a black body cavity sensor, constructed with a thin platinum film sputtered on a sapphire rod tip, were examined and compared with those of bare or sheathed thermocouples. For time averaged temperature measurements by the OFT, the radiative heat loss is significant in the temperature range of flames. For fluctuating temperatures the OFT output has a slow response, due to its thermal inertia, which depends on the diameter of the sensor and flow conditions; in spite this the rapid response of the OFT is emphasized in the literature with the assumption of the ideal thermal behavior of the thin sputtered film ( 4 m) on a sapphire rod of 0.25 mm diameter. The fluctuation waveform predicted by the present numerical simulation agrees satisfactorily with the measured one, which proves that the major factor affecting the thermal inertia of an OFT sensor is the heat capacity of sapphire. A special compensation technique is needed to improve the response of the OFT.     

Highly fluorinated C18 fatty acids: synthesis and interfacial properties

A fluorinated oleic acid 1-Z containing a perfluorooctyl group and its analogues (E-isomer 1-E, alkyne type 2 and saturated type 3) were synthesized in good yields. In these syntheses, it was found that a key compound 5 could be converted to each of 1-Z, 1-E and 2. Furthermore, equilibrium spreading pressures of their monolayers at the air-water interface were measured in order to demonstrate how the degree of unsaturation in the hydrophobic chain, the geometric isomerization, and the presence of F-atoms influence the monolayer stability. Irrespective of the structural alteration in the hydrophobic chains, the fluorinated fatty acids formed more stable monolayers with high spreading pressures as compared to their hydrocarbon counterparts.     

Asymmetric aldol reaction of amide enolates bearing trans-2,5-disubstituted pyrrolidines as chiral auxiliaries

Condensation of aldehydes with Zr enolate of chiral $\text{N}$-propionyl-$\text{trans}$-2,5-disubstituted pyrrolidine proceeded with high diastereo- and diastereoface-selection. Stereoselectivity in the reaction of the corresponding $\text{N}$-acetyl compounds was also examined.     

Ammonia IRMS-TPD measurements and DFT calculation on acidic hydroxyl groups in CHA-type zeolites

Br?nsted acidity of H-chabazite (CHA) zeolites (Si : Al(2) = 4.2) was investigated by means of ammonia infrared-mass spectrometry/temperature-programmed desorption (IRMS-TPD) methods and density functional calculations. Four IR bands were observed at 3644, 3616, 3575 and 3538 cm(-1), and they were ascribable to the acidic OH groups on four nonequivalent oxygen sites in the CHA structure. The absorption band at 3538 cm(-1) was attributed to the O(4)H in the 6-membered ring (MR), and ammonia adsorption energy (DeltaU) of this OH group was the lowest among the 4 kinds of OH groups. The other 3 bands were assigned to the acidic OH groups in 8MR. It was observed that the DeltaU in 8 and 6MR were 131 (+/-3) and 101 kJ mol(-1), respectively. On the other hand, the density functional theory (DFT) calculations within periodic boundary conditions yielded the adsorption energies on these OH groups in 8 and 6MR to be ca. 130 and 110 kJ mol(-1), respectively, in good agreement with the experimentally-observed values.