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11.
Yoko Masuda Kozue Hirabayashi Keiko Sakuma Tadashi Nakanishi 《Colloid and polymer science》2002,280(5):490-494
The swelling behavior of poly(ethylene oxide) (PEO) gels in aqueous solutions of sodium dodecyl sulfate (SDS) with and without
NaCl was investigated. In the absence of NaCl, PEO gels with different degrees of cross-linking began to swell from a concentration
lower than the critical micelle concentration (cmc) of SDS, then showed sigmoidal enhancements of swelling in a higher SDS
concentration region until the degrees of swelling reached maximum values. The SDS concentration at which the swelling began
to appear was in reasonable agreement with the critical aggregation concentration (cac) value reported for the aqueous PEO
system. For the cases where NaCl was present, the swelling behavior of PEO gel was different from that when NaCl was absent
in the following way. The concentrations where the swelling begins to appear, and hence those where the degree of swelling
rises steeply, decreased with an increase in NaCl concentration. The ultimate degrees of swelling at higher concentration
regions also decreased with an increase in the NaCl concentration. The lowering of the SDS concentrations at which the PEO
gel began to swell is in line with the decreases in the cmc of SDS solutions containing NaCl and also with the decreases in
the cac of PEO solution.
Electronic Publication 相似文献
12.
The ionic conduction of cation substituted CuBrTe, CuxAg1−xBrTe solid solutions, is investigated in the temperature range between 100 and 400 K. The change of electrical conductivities with temperature in the range of 0.94≤x<1 shows the characteristics of second-order rather than first-order phase transitions. The replacement of Cu with the Ag cation in CuxAg1−xBrTe leads to an increase in conductivity especially in the β and γ-phases. 相似文献
13.
Xianglian T. Sakuma K. Basar H. Takahashi 《Journal of Thermal Analysis and Calorimetry》2010,99(1):65-69
New inorganic compounds having the general formula (Bi2O3)1−x
(Lu2O3)
x
(x ranges from 0.1 to 0.5) displaying orange colours have been synthesized by traditional solid-state route, as viable alternatives
to lead, cadmium and chromium based yellow toxic inorganic pigments. The host lattice of these pigments is Bi2O3 that is doped by Lu3+ ions. The goal was to develop conditions for the synthesis of these compounds and to determine the influence of calcination
temperature and lutetium content on their colouring effects. The simultaneous TG-DTA measurements were used for determination
of the temperature region of the pigment formation and thermal stability of pigments. The pigments were also evaluated from
the standpoint of their structure and particle sizes. 相似文献
14.
Mizukami S Wu F Sakuma A Walowski J Watanabe D Kubota T Zhang X Naganuma H Oogane M Ando Y Miyazaki T 《Physical review letters》2011,106(11):117201
Spin precession with frequencies up to 280 GHz is observed in Mn(3-δ)Ga alloy films with a perpendicular magnetic anisotropy constant K(u)~15 M?erg/cm(3). The damping constant α, characterizing macroscopic spin relaxation and being a key factor in spin-transfer-torque systems, is not larger than 0.008 (0.015) for the δ=1.46 (0.88) film. Those are about one-tenth of α values for known materials with large K(u). First-principles calculations well describe both low α and large K(u) for these alloys. 相似文献
15.
Sigfridsson A Haraldsson H Ebbers T Knutsson H Sakuma H 《Magnetic resonance imaging》2011,29(2):202-208
Aim
The influences on the signal-to-noise ratio (SNR) of Displacement ENcoding with Stimulated Echoes (DENSE) MRI of field strength, receiver coil sensitivity and choice of flip angle strategy have been previously investigated individually. In this study, all of these parameters have been investigated in the same setting, and a mutual comparison of their impact on SNR is presented.Materials and methods
Ten healthy volunteers were imaged in a 1.5 T and a 3 T MRI system, using standard five- or six-channel cardiac coils as well as 32-channel coils, with four different excitation patterns. Variation of spatial coil sensitivity was assessed by regional SNR analysis.Results
SNR ranging from 2.8 to 30.5 was found depending on the combination of excitation patterns, coil sensitivity and field strength. The SNR at 3 T was 53±26% higher than at 1.5 T (P<.001), whereas spatial differences of 59±26% were found in the ventricle (P<.001). Thirty-two-channel coils provided 52±29% higher SNR compared to standard five- or six-channel coils (P<.001). A fixed flip angle strategy provided an excess of 50% higher SNR in half of the imaged cardiac cycle compared to a sweeping flip angle strategy, and a single-phase acquisition provided a sixfold increase of SNR compared to a cine acquisition.Conclusion
The effect of field strength and receiver coil sensitivity influences the SNR with the same order of magnitude, whereas flip angle strategy can have a larger effect on SNR. Thus, careful choice of imaging hardware in combination with adaptation of the acquisition protocol is crucial in order to realize sufficient SNR in DENSE MRI. 相似文献16.
This is the second of a series of papers which give a necessary and sufficient condition for two essential simple loops on a 2-bridge sphere in a 2-bridge link complement to be homotopic in the link complement. The first paper of the series treated the case of the \(2\) -bridge torus links. In this paper, we treat the case of \(2\) -bridge links of slope \(n/(2n+1)\) and \((n+1)/(3n+2)\) , where \(n \ge 2\) is an arbitrary integer. 相似文献
17.
Ichiro Tsunenari Jyoji Yamate Masae Iwaki Mitsuru Kuwamura Takao Kotani Sadashige Sakuma 《Microscopy and microanalysis》2003,9(6):532-541
Angiogenesis, a biologic process whereby endothelial cells divide and migrate to form new blood vessels, is a key step in tumor growth, invasion, and metastasis. In the present study, we investigated the differences in angioarchitecture between two different tumors induced by cloned cell lines (MT-8 and MT-9), derived from a transplantable rat malignant fibrous histiocytoma, by scanning electron microscopy of vascular corrosion casts. During a 3-week observation period after implantation, the growth of MT-8 tumors appeared to be faster than that of MT-9 tumors. Histologically, MT-8 tumors were of the uniformly undifferentiated sarcoma type arranged in characteristic organoid structures, and MT-9 tumors showed a storiform growth pattern. In MT-8 tumors, neovascularization occurred by sprouting at postimplantation (PI) week 1, and the newly formed capillaries gradually became more tortuous. In MT-9 tumors, at PI week 1, the corrosion casts of newly formed capillaries mainly showed a wavy course but no finger-like outgrowths of capillaries were seen. At PI weeks 2 and 3, the sprouting was seen specifically in MT-9 tumors, forming basket-like structures and glomeruloid structures of capillaries. These results indicate that angiogenesis or angioarchitecture of MT-8 tumors is different from that of MT-9 tumors, depending on the differences in their tumor histology and by the features like absence or presence of basket-like structures and glomeruloid structures of capillaries. 相似文献
18.
Yokoi T Sakuma J Maeda K Domen K Tatsumi T Kondo JN 《Physical chemistry chemical physics : PCCP》2011,13(7):2563-2570
The confined space synthesis method has been applied to the preparation of sodium tantalate (NaTaO(3)); hydrothermal reaction of NaOH and Ta(2)O(5) was carried out in the pores of a three-dimensional mesoporous carbon, which was replicated by the colloidal array of silica nanospheres (SNSs) 20 nm in size. This approach led to the formation of a colloidal array of NaTaO(3) nanoparticles 20 nm in size with a surface area of 34 m(2) g(-1). The photocatalytic performance of the colloidal array of NaTaO(3) nanoparticles for overall water splitting under UV irradiation (λ > 200 nm) was evaluated after loading a NiO cocatalyst onto NaTaO(3) samples. The NiO-loaded NaTaO(3) nanoparticles showed photocatalytic activity for overall water splitting more than three times as high as non-structured bulk NaTaO(3) particles. 相似文献
19.
The X-ray diffraction measurement for superionic conducting glass 5Agl–3Ag2O–2V2O5 was carried out at 12, 100, 200 and 290 K. The temperature dependence of structure factor S(Q) of 5Agl–3Ag2O–2V2O5 has been discussed based on the theoretical treatment that includes thermal vibration of atoms in noncrystalline materials. The effective overall Debye–Waller temperature parameter B increases with the increase of temperature. 相似文献
20.
Arai M. Sakuma T. Atake T. Kawaji H. 《Journal of Thermal Analysis and Calorimetry》2002,69(3):905-908
The phase transition and the crystal structures of CuITe were investigated by differential thermal analysis and X-ray powder
diffraction measurements in the temperature range between 300 and 683 K. The new phase transition in CuITe was observed at
592 K. The enthalpy of transition is ΔH=0.125 kJ mol-1. The new phase above 592 K belongs to tetragonal system with the space group I41
/amd.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献