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111.
112.
Unsymmetrical diphosphenes carrying bulky aryl and phenoxy groups were prepared by the reaction of lithium 2,4,6-tri-t-butylphenylphosphide with the corresponding phenyl phosphorodichloridites, followed by the dehydrochlorination reaction with 1,8-diazabicyclo[5.4.0]undec-7-ene. The diphosphenes were isolated as stable compounds. The reactions of these diphosphenes with elemental sulfur or selenium afforded the corresponding thiadiphosphiranes or selenadiphosphiranes, respectively. The diphosphenes also reacted with dichlorocarbene to give dichlorodiphosphiranes.  相似文献   
113.
应用XPS,XAES和紫外漫反射光谱法研究了CuO-ZnO/氧化物上CO2/H2合成甲醇的反应活性中心.CuO-ZnO/氧化物催化剂上的反应活性中心是存在于CuO-ZnO固溶体中的Cu-Zn-O("□"为氧空位),活性中心的Cu价态为Cu-和Cu0.反应活性中心在CuOZnO-ZrO2催化剂上比在其它CuO-ZnO/氧化物催化剂如CuO-ZnO,CuO-ZnO-MgO,CuOZnO-Al2O3和CuO-ZnO-r2O3上更加稳定.  相似文献   
114.
A new apparatus has been built that annexes a normal electrocardiograph, ECG, with the aim to enhance its capacity. It adds the normal ECG power to superpose multiple records of ECG altogether and averages out them and, further, makes sophisticated analysis, such as normalizing the peak heights, evaluating the half-line widths of the peaks, or that of the standard deviations of measurements like the inter peak distances. The results of the said calculations have not been obtainable using the former instruments, and are expected to be useful for clinicians.  相似文献   
115.
In the secondary ion mass spectrometry (SIMS) of organic substances, the molecular weight of the intact ions currently detectable is at best only as high as 1000 Da, which for all practical purposes prevents the technique from being applied to biomaterials of higher mass. We have developed SIMS instrumentation in which the primary ions were argon cluster ions having a kinetic energy per atom, controlled down to 1 eV. On applying this instrumentation to several peptides and proteins, the signal intensity of fragment ions was decreased by a factor of 102 when the kinetic energy per atom was decreased below 5 eV; moreover, intact ions of insulin (molecular weight (MW): 5808) and cytochrome C (MW: 12 327) were detected without using any matrix. These results indicate that fragmentation can be substantially suppressed without sacrificing the sputter yield of intact ions when the kinetic energy per atom is decreased to the level of the target's dissociation energy. This principle is fully applicable to other biomolecules, and it can thus be expected to contribute to applications of SIMS to biomaterials in the future. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   
116.
A carpetlike dense‐layer formation between a hydrophobic layer and a polyelectrolyte brush layer has been found in the monolayers of an ionic amphiphilic diblock copolymer, poly(1,1‐diethylsilacyclobutane)mblock‐poly(methacrylic acid)n, on a water surface by an X‐ray reflectivity technique. By detailed analysis, we have found that the hydrophilic layer under the water is not a simple layer but is divided into two layers, that is, a carpetlike dense methacrylic acid (MAA) layer near the hydrophobic layer and a polyelectrolyte brush layer. We have also confirmed that a well‐established polyelectrolyte brush is formed only for the m:n = 43:81 polymer monolayer: For m:n = 40:10 and m:n = 45:60 polymer monolayers, only a dense MAA layer is formed. This dense‐layer formation should be the origin of the interesting hydrophobic‐layer thickness variation previously reported; The hydrophobic‐layer thickness takes a minimum as a function of the hydrophilic chain length at any surface pressure studied. An overview of the data for three samples with different chain lengths (m:n = 40:10, 45:60, or 43:81) has shown that the thickness of this dense layer is 10–20 Å and is independent of the surface pressure and polymerization degree of poly(methacrylic acid) (PMAA) in the range studied. This dense‐layer formation is explained by the reasonable speculation that contact with PMAA is thermodynamically more stable than direct contact with water for the diethylsilacyclobutane (Et2SB) layer on water. In this sense, the dense layer acts like a carpet for the hydrophobic Et2SB layer, and a 10–20‐Å thickness could be a critical value for the carpet. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1921–1928, 2003  相似文献   
117.
Several episodes, never printed except in Japanese, related to the young days of Yonezo Morino are documented. Stories highlight how his personal contacts with his teachers and colleagues and his studies and experiences in spectroscopy, quantum theory etc. had influenced his early works on gas-phase electron diffraction (GED).  相似文献   
118.
The permutation-inversion group developed by Longuet-Higgins is extended to a classification of the vibronic, torsional, and rotational wavefunctions of a nonrigid X2Y2 molecule by introducing a symmetry operation T?, which rotates the top half of the molecule by 2π and, accordingly, the molecule-fixed x axis by π. Since the energy levels of linear (Dh) and bent (C2h, C2h, and C2) forms of X2Y2 are classified according to a set of common symmetry operations of this extended permutation-inversion group, their energy levels can be correlated, including those of nonrigid forms such as a quasilinear system or a free internal rotor. Nuclear spin weights and selection rules are derived.  相似文献   
119.
The semiconductor-to-metal transition was observed in GaP under very high pressure exceeding 500 kbar. At the transition the electrical resistance decreased almost instantaneously by five orders of magnitude. This study was also carried out on BP and SiC and no drastic change was observed in their electrical resistance.  相似文献   
120.
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