A new spectroscopic method using the Fraunhofer diffraction pattern

Conclusions From the results shown above, it may be said that this new spectroscopic method using the Fraunhofer diffraction pattern has the possibility of practical use. This method has the advantages that the multiplex gain is retained and the experimental apparatus is very simple as compared with the conventional grating spectroscopy. The resolution is about 1.25A/2KX and becomes higher with the increase of the number of slits and the maximum value of variable in the diffraction pattern. The other way, the simultaneous equations become more difficult to solve with the increase of resolution and at present the maximum value of N_S is 21. In such a case the adjustment factor A and the figure of condition of matrix are important. Further, large memory of the electronic computer is required, for example, 2.56MB for N=800. The experimental setup is now under construction in order to verify the usefulness of this method in the far infrared region.     

Absolute Positioning of Scanning Probe Microscope Tip by Two-Wavelength Synthetic Method

In this paper, we describe the absolute positioning of a probe tip in a scanning Wiener fringe optical microscope (SWOM) using a synthetic wavelength method. Two laser beams with different wavelengths are superimposed and are incident on a sample surface. A synthetic fringe which has a longer period than that of the Wiener fringe obtained with a single wavelength is formed on the surface. The order of Wiener fringe which is utilized as a feedback signal in the microscope can be determined by the synthetic fringe. A sample with known structure was observed for various defined fringe orders using the SWOM.     

Shear-Force Detection by Reusable Quartz Tuning Fork without External Vibration

Many studies have reported on the use of quartz tuning forks (a type of crystal oscillator used in wristwatches) in the detection of shear force, employed to control the distance between the probe and the sample in a scanning near-field optical microscope. This study focuses on a newly-devised shear force detection method capable of simultaneous non-external oscillation and detection, which also allows for subsequent reuse of a tuning fork. The optimum configuration and tip length for inserting a probe into the slit of a tuning fork have been elucidated. The shear force was detectable in about 5 nm decay length using such conditions.     

Characteristics of the Na/beta-alumina/Na cell as a sodium vapor pressure sensor

The EMF and voltage-current characteristics for a galvanic cell with the configuration Na vapor (P₁)/sodium beta-alumina/Na vapor (P₂) were studied. It was verified that the EMF followed the Nernst relation over a wide pressure range. For example, when P₁ = 2 × 10^-2 mm Hg and beta-alumina temperature = 340°C, the measured EMF agreed with the calculated value in P₂ range from 10^-5 to 10^-2 mm Hg. At lower pressure range, the measured EMF showed a negative deviation. Coexisting argon gas did not influence the cell EMF characteristic. In an atmosphere containing oxygen, the measured EMF was very high at first. Then it decreased and finally approached a value which agreed with the Nernst equation after several hours. At low beta-alumina temperatures, current saturation was observed in the voltage versus current relation with the anode on the P₂ side. Although the sodium pressure could be determined from saturating current measurement, the measurable pressure range was narrower than that for EMF measurement. At high beta-alumina temperature, current saturation was not clear. Values of 6 × 10^-6 (Ω cm)^-1 for the electron conductivity and 6 × 10^-10 (Ω cm)^-1 for the hole conductivity at 340° were obtained for beta-alumina from the voltage-current characteristics at low sodium pressure.     

Total synthesis of (+/-)-gleenol and (+/-)-axenol via a functionalized spiro[4.5]decane

Total synthesis of the biologically important axane sesquiterpenes, gleenol (1) and axenol (2), was accomplished through a readily available spiro[4.5]decane. The key features of the synthesis of 1 and 2 include Claisen rearrangement to afford the multi-functionalized spiro[4.5]decane 4 as a single diastereomer in excellent yield, installation of the C7 isopropyl group via ketene dithioacetal instead of direct alkylation and a diastereoselective reduction of ketone under the Birch conditions.     

Synthetic study on telomerase inhibitor, D8646-2-6: synthesis of the key intermediate using Sn(OTf)2 or Sc(OTf)3 mediated aldol-type reaction and Stille coupling

The synthesis of the key intermediate (4) in the proposed route to D8646-2-6 is described. The aldol reaction of the carbohydrate-containing pyrone 7 with the aldehyde 6 was accomplished by using LiHMDS and Sc(OTf)3 or Sn(OTf)2. The stepwise dehydration reaction of the aldol adduct 14, followed by Stille coupling with vinyl stannane 5 which contained phosphonate gave the desired 4.     

Monte Carlo calculation of second and third virial coefficients of small-scale comb polymers on lattice

This paper reports the first computational estimation of the comb polymers' third virial coefficients. The number of the chains in the comb polymers range from 5 to 11. An algorithm that counts the contributing terms of the third virial coefficients in an accelerated manner is presented along with its efficiency dependence on the polymers' size. In addition, the second virial coefficients are estimated for the comb polymers and compared to previously reported results.     

Synthetic study of diversifolin: the construction of 11-oxabicyclo[6.2.1]undec-3-ene core using ring-closing metathesis

Stereoselective synthesis of a potential intermediate bearing 11-oxabicyclo[6.2.1]undec-3-ene core, a common scaffold of biologically active germacrane-type sesquiterpenes, has been achieved. Synthetic features involve formal 1,3-asymmetric induction, unusual ring-closing metathesis constructing a 10-membered carbocycle system, and unique lactone transposition.     

Diastereoselective synthesis of 3,3-disubstituted oxindoles from atropisomeric N-aryl oxindole derivatives

Diastereoselective synthesis of 3,3-disubstituted oxindoles has been examined by transformations involving nucleophilic addition, alkylation, and cycloaddition using chiral racemic N-aryl oxindoles bearing C–N axial chirality. The most striking features of this approach are high diastereoselectivities (up to >95:<5) when using ortho-monosubstituted N-aryl oxindoles and easy removal of the p-(benzyloxy)aryl moiety in the axially twisted amides by a mild two-step sequence.