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排序方式: 共有370条查询结果,搜索用时 15 毫秒
21.
Natsuki Yamashita Atsuhito Tadokoro Eiichiozu Toshihisa Maeshima Ion C. Baianu Lun-Shin Wei 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(10):1223-1239
The anionic polymerization of acrolein (AL) with N, N-dimethylamino-propylacrylamide (DMAPA) in the presence of water was investigated in tetrahydrofuran, benzene, and ethanol at 0°C in a nitrogen atmosphere. The resulting polymers were found to be essentially vinyl polymers with one DMAPA attached and an aldehyde side chain. From observations of the polymerization process by 1H NMR, we find that polymerization was initiated by the hydroxyl anion formed in the thermodynamic equilibrium between the amine of DMAPA and water. The hydrogen transfer reaction of DMAPA was caused by the propagating poly-AL anion. On the other hand, the monomer reactivity ratios and the Q2-e2values of DMAPA were determined by the free-radical copolymerization of styrene (St, M1) with DMAPA and AIBN as initiator. 相似文献
22.
Based on the fact that anthracene (Anth) possesses much higher similarity in electron-releasing ability to porphyrin nucleus than the other polyacenes, the dimeric octaethylporphyrin (OEP) derivatives 4 and 5 (OEP–Anth–OEP) were synthesized and their structure–property relationships were examined, as compared with related OEP dimers 1–3. Among them, the derivative 4 showed enormously high electronic communication between two terminal OEP rings, potentially providing a suitable unit of the electronic structure for molecular design of the OEP devices operating with less energy and with higher sensitivity to outside stimuli. 相似文献
23.
Satoshi Nagao Ayaka Suda Hisashi Kobayashi Naoki Shibata Yoshiki Higuchi Shun Hirota 《化学:亚洲杂志》2020,15(11):1743-1749
Domain swapping is an exception to Anfinsen's dogma, and more than one structure can be produced from the same amino acid sequence by domain swapping. We have previously shown that myoglobin (Mb) can form a domain‐swapped dimer in which the hinge region is converted to a helical structure. In this study, we showed that domain‐swapped dimerization of Mb was achieved by a single Ala mutation of Gly at position 80. Multiple Ala mutations at positions 81 and 82 in addition to position 80 facilitated dimerization of Mb by stabilization of the dimeric states. Domain swapping tendencies correlated well with the helical propensity of the mutated residue in a series of Mb mutants with amino acids introduced to the hinge region. These findings demonstrate that a single mutation in the hinge loop to modify helical propensity can control oligomer formation, providing new ideas to create high‐order protein oligomers using domain swapping. 相似文献
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Sekiguchi K Sakai H Witała H Glöckle W Golak J Hatanaka K Hatano M Itoh K Kamada H Kuboki H Maeda Y Nogga A Okamura H Saito T Sakamoto N Sakemi Y Sasano M Shimizu Y Suda K Tamii A Uesaka T Wakasa T Yako K 《Physical review letters》2005,95(16):162301
Three precise measurements for elastic pd scattering at 135 MeV/A have been performed with the three different experimental setups. The cross sections are described well by the theoretical predictions based on modern nucleon-nucleon forces combined with three-nucleon forces. Relativistic Faddeev calculations show that relativistic effects are restricted to backward angles. This result supports the two measurements recently reported by RIKEN and contradicts the KVI data. 相似文献
27.
M. Nurhuda A. Suda M. Kaku K. Midorikawa 《Applied physics. B, Lasers and optics》2007,89(2-3):209-215
We present a study on the optimization of multi-mJ spectral broadening in neon-filled hollow fibers using pressure gradients.
It is found that the intensity of the laser pulse at the entrance of the hollow fiber should be below or at the level where
multi-photon ionization (MPI) starts to occur. If the intensity is higher than the threshold value for MPI, ionization can
significantly reduce the throughput efficiency. The extension of the scheme to a terawatt power level is also addressed.
PACS 42.65.Re; 42.65.Jx; 42.65.k 相似文献
28.
H. Mardanpour H. R. Amir-Ahmadi A. Deltuva K. Itoh N. Kalantar-Nayestanaki T. Kawabata H. Kuboki Y. Maeda J. G. Messchendorp S. Sakaguchi H. Sakai N. Sakamoto Y. Sasamoto M. Sasano K. Sekiguchi K. Suda Y. Takahashi T. Uesaka H. Witała K. Yako 《The European Physical Journal A - Hadrons and Nuclei》2007,31(3):383-391
High-precision vector and tensor analyzing powers of elastic deuteron-proton ( d + p) scattering have been measured at intermediate energies to investigate effects of three-nucleon forces. Angular distributions
in the range of 70°-120° in the center-of mass frame for incident-deuteron energies E
d
lab = 130 and 180 MeV were obtained using the RIKEN facility. The beam polarization was unambiguously determined by measuring
the ^12C (d, α)^10B(2+) reaction at 0°. Results of the measurements are compared with state-of-the-art three-nucleon calculations. The present modeling of nucleon-nucleon
forces and its extension to the three-nucleon system is not sufficient to describe the high-precision data consistently and
requires, therefore, further investigation. 相似文献
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