Novel Host Compounds, 1,1′-Binaphthyl-2,2′-Dihydroxy-5,5′- and 6,6′-Dicarboxylic Acid, which Trap Guest Molecules Tightly in their Inclusion Crystals

The host compounds 1,1’-binaphthyl-2,2′-dihydroxy-5,5′-dicarboxylic acid (1) and 1,1′-binaphthyl-2,2′-dihydroxy-6,6′-dicarboxylic acid (2) have been synthesized, and their inclusion properties have been studied. Inclusion complexes formed by 1 and 2 with volatile guests such as acetone and methanol release the guests only at much higher temperatures than their boiling points. The crystal structures of the inclusion complexes have been determined from single crystal X-ray diffraction data and show different host lattices.     

Development of miniaturized multi-channel high-performance liquid chromatography for high-throughput analysis

We have developed miniaturized multi-channel high-performance liquid chromatography (HPLC) system. With this system, we can simultaneously separate multiple samples, using a single high-pressure gradient pump, a chip-based sample injection unit, a monolithic silica capillary column array, and a multi-channel UV detection unit based on fiber optics. The injection unit has a simplified structure composed of brass housing and a quartz microchip having microchannels and access ports, which enable a direct injection of sample to multi-channel by commercial multichannel micropipette. Moreover, that possesses a function of microvalve, and on-chip definition of sample injection plugs achieved with a cross channel injection method, providing each column of monolithic silica capillary array. The substances in channels were simultaneously detected with UV having multiple cells. Standard samples were analyzed for characterizing newly developed system, and sharp peaks were obtained with reproducibility data of < 0.9% (R.S.D.). Analysis of tryptic digestion of casein was also employed. These results show that the novel multi-channel HPLC system has the benefits for the high-throughput analysis in the post-genomic analysis/combinatorial chemistry.     

Effect of explicit cationic size and valence constraints on the phase stability of 1:2 B-site-ordered perovskite ruthenates

The related parameters of cation size and valence that control the crystallization of Sr(3)CaRu(2)O(9) into a 1:2 B-site-ordered perovskite structure were explored by cationic substitution at the strontium and calcium sites and by the application of high pressure. At ambient pressures, Sr(3)MRu(2)O(9) stoichiometries yield multiphasic mixtures for M = Ni(2+), Mg(2+), and Y(3+), whereas pseudocubic perovskites result for M = Cu(2+) and Zn(2+). For A-site substitutions, an ordered perovskite structure results for Sr(3-x)Ca(x)CaRu(2)O(9), with 0 相似文献   

Magnetic properties of isostructural BaCoP2O7, BaNiP2O7, and BaCuP2O7 studied with dc and ac magnetization and specific heat

Magnetic properties of three isostructural compounds BaMP2O7 (M = Co, Ni, and Cu) were investigated by dc and ac magnetization and specific heat measurements. BaCuP2O7 was shown to be an excellent quasi-one-dimensional linear-chain Heisenberg antiferromagnet with an exchange constant (J/kB) of 103.8 K (Hamiltonian H = J Sigma SiS(i+1)) and a temperature for the long-range magnetic order (TN) of 0.81 K giving the ratio kBTN/J = 0.78%. BaCoP2O7 and BaNiP2O7 exhibited long-range antiferromagnetic order at TN = 10.4 and 10.1 K, respectively. BaCoP2O7 and BaNiP2O7 showed a large contribution of the short-range correlation above TN. BaNiP2O7 remained in the antiferromagnetic state up to 90 kOe at 2 K, whereas BaCoP2O7 demonstrated two metamagnetic phase transitions at about 52 and 71 kOe at 2 K if the magnetic field was parallel to the easy direction. BaMP2O7 melted incongruently at 1323 K (M = Co), 1344 K (M = Ni), and 1338 K (M = Cu).     

Investigation of the crystal structure and the structural and magnetic properties of SrCu2(PO4)2

SrCu2(PO4)2 was prepared by the solid-state method at 1153 K. Its structure was solved by direct methods in the space group Pccn (No. 56) with Z = 8 from synchrotron X-ray powder diffraction data measured at room temperature. Structure parameters were then refined by the Rietveld method to obtain the lattice parameters, a = 7.94217(8) A, b = 15.36918(14) A, and c = 10.37036(10) A. SrCu2(PO4)2 presents a new structure type and is built up from Sr2O16 and Cu1Cu2O8 units with Cu1...Cu2 = 3.256 A. The magnetic properties of SrCu2(PO4)2 were investigated by magnetic susceptibility, magnetization up to 65 T, Cu nuclear quadrupole resonance (NQR), electron-spin resonance, and specific heat measurements. With spin-dimer analysis, it was shown that the two strongest spin-exchange interactions between Cu sites result from the Cu1-O...O-Cu2 and Cu2-O...O-Cu2 super-superexchange paths with Cu1...Cu2 = 5.861 A and Cu2...Cu2 = 5.251 A, and the superexchange associated with the structural dimer Cu1Cu2O8 is negligible. The magnetic susceptibility data were analyzed in terms of a linear four-spin cluster model, Cu1-Cu2-Cu2-Cu1 with -2J(1)/kB = 82.4 K for Cu1-Cu2 and -2J(2)/k(B) = 59 K for Cu2-Cu2. A spin gap deduced from this model (Delta/kB = 63 K) is in agreement with that obtained from the Cu NQR data (Delta/kB = 65 K). A one-half magnetization plateau was observed between approximately 50 and 63 T at 1.3 K. Specific heat data show that SrCu2(PO4)2 does not undergo a long-range magnetic ordering down to 0.45 K. SrCu2(PO4)2 melts incongruently at 1189 K. We also report its vibrational properties studied with Raman spectroscopy.     

Transient DSC,a Novel and Rapid Method for Assessing Pharmaceutical Powder Compacts

The previously described method involving the use of transient DSC was applied to pharmaceutical powder compacts and to ceramic powder compacts. The samples were prepared by compressing powders of pentaerythritol tetraacetate and two kinds of alumina powder (differing in particle size distribution) up to a pressure of 20 MPa by using a jig. For pentaerythritol tetraacetate, a linear relationship was obtained between the parameter obtained by DSC and the compaction pressure. This revised version was published online in August 2006 with corrections to the Cover Date.     

Mössbauer and NMR studies of iron-carbon martensite

The atomic arrangements in Fe-C martensite, especially the interstitial carbon positions have been discussed utilizing⁵⁷Fe Mössbauer spectroscopy and¹³C and⁵⁷Fe spin-echo NMR measurements. The experimental result is well explained by the model of two interstices occupancy of carbon in the bct martensite. Especially, the spin-echo spectra by¹³C nuclei showed that two main lines first appear and clear satellite lines gradually rise during the aging at 323K, suggesting the carbon jumps from the tetrahedral to the octahedral interstices and further movements to form a local ordered arrangement.     

On some limit theorems of probability distributions

Annals of the Institute of Statistical Mathematics - In Part I the Khintchine’s uniqueness theorem for the class convergence of probability distributions is proved in a natural way by making...     

Sasakian manifolds with vanishing C-Bochner curvature tensor

Supported by TGRC-KOSEF.     

A microporous membrane-based continuous generation system for trace-level standard mixtures of atmospheric gases.

A reliable and convenient system to generate accurate and stable standard gas mixtures of various atmospheric compounds at parts-per-billion levels has been developed. The system is of simple design; the generator is a coil consisting of an inner tube of microporous polytetrafuluoroethylene (PTFE) membrane tubing and an outer tube of silicone tubing. An aqueous solution of the given compound continuously flows through the inner microporous tube and the purge gas flows through the annulus between the inner and outer tubes. In addition to the generation of gas mixtures based on Henry's law, the proposed flow-type system offers generation based on chemical reactions, leading to a distinct advantage of the availability of continuous sources of various compounds. The generation system was tested for preparing standard gas mixtures of HCHO and H2O2 on the basis of Henry's law, and those of HNO2, NO, and SO2 on the basis of chemical reactions. A stable generation of the desired low concentrations of various kinds of gas mixtures can be readily achieved by adjusting the concentration of the solution without the use of high-dilution flow.