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排序方式: 共有510条查询结果,搜索用时 31 毫秒
1.
Using the SiO2 and Al2O3 components of the amorphous phase in coal fly ash (Fa), Fa was converted to Na-X zeolites in NaOH-NaAlO2 solutions by stirring at 35°C for 72 hr and then aging at 85°C for a given period. The molar ratio SiO2/Al2O3 of the starting materials was controlled from 2.0 to 13.2. The resulting materials were characterized by various means. Increasing the SiO2/Al2O3 ratio of the starting material increased the degree of crystallinity of faujasite, exhibiting a maximum at SiO2/Al2O3 = 8.0. The faujasite formed was identified as Na-X zeolite with Si/Al = 1.20. The amorphous phase in Fa was dissolved during the stirring to form a precursor of zeolite, such as amorphous aluminosilicate. The Na-X zeolite was formed by aging for 24 hr, and the degree of crystallinity of this material was increased with the increasing aging period. The cation exchange capacity and specific surface area were increased with the increasing degree of crystallinity of the Na-X zeolites. 相似文献
2.
A mass spectrometric technique combined with a double Knudsen cell was used to determine the antimony and copper activities
in the Cu-Sb binary system at 1373 K and in the two-melt composition range of the Cu−S−Sb ternary system at 1423 K. The antimony
and copper activities were calculated based on the intensity ration of the gaseous Sb and Cu species, over the unknown and
known activity samples, respectively. γ
Sb
o
were found to be 1.1×10−2 in molten copper at 1373 K, and 1.8×10−2 and 0.44 in a copper-rich phase and in a matter phase, of the Cu−S−Sb ternary system at 1423 K, respectively. These values
indicate, that antimony can be removed during the matte smelting and slagging stage of the copper smelting process. Interaction
parameters of antimony in molten copper slagging stage of the copper smelting process. Interaction parameters of antimony
in molten copper at 1423 K were calculated and found to be 10.7, −5.4, and 6.3 for ε
Sb
Sb
· ρSb
Sb, and ε
Sb
S
, respectively.
M. HINO, formerly Visiting Scientist at the University of Toronto 相似文献
3.
The distribution ratios of Fe and B between molten Fe–B alloy and molten Ag were measured at temperatures between 1573 and 1923 K. Also, distribution ratios of Fe and B between molten Fe–B–Csatd. alloys and molten Ag were measured at 1873 K. It was found that the excess Gibbs free energy of mixing in molten Fe–B and Fe–B–C alloys can be expressed by utilizing the Redlich–Kister polynomial. The activity curves of the elements in molten Fe–B alloy and Fe–B–C alloy were estimated. 相似文献
4.
Makoto Hino Minoru Hiramatsu Koichi Akiyama Hitoshi Kawasaki Masato Tsujikawa Makoto Kawamoto 《Materials and Manufacturing Processes》1997,12(1):37-46
A high powered YAG laser with kaleidoscope for surface modification was applied to the surface hardening of carbon steels containing 0. 18-0.54 wt% C without the absorbents, and the relationships between laser processing and surface hardening were investigated by hardness and microstructure. The structure of the hardened zone underwent complete martensitic transformation in all of the carbon steels tested, and its hardness increased with greater carbon content. Under identical irradiated conditions, the hardened zone expanded with increasing carbon content. A hardened zone extending from the surface to a depth of 1.0 mm was obtained at a laser power of 1.0 kW and a scanning speed of 1 mm/sec. It was found that in the surface hardening of carbon steels, a high powered YAG laser can be used to control the hardened zone by selecting the appropriate irradiation conditions, however, the hardened zone was affected by the assistant gas and the flow rate. 相似文献
5.
Araki K. Saito H. Yuasa N. Rei T. Itozaki H. Higaki K. 《IEEE transactions on magnetics》1992,28(3):1805-1809
Broadband measurements have been done on high T c superconducting coplanar lines of YBa2Cu3O 7 on [100]MgO substrates. From the transmission and reflection coefficients of coplanar lines, the characteristic impedance, attenuation constant, phase constant, group velocity, and London penetration depth of the film are derived, based on the circuit models 相似文献
6.
Y Mazaki H Uchida O Hino S Hashimoto H Sabe 《Canadian Metallurgical Quarterly》1998,273(35):22435-22441
Paxillin, a focal adhesion protein, exists as multiple isoforms in humans (alpha, beta, and gamma). To understand more about the physiological role of each isoform, we have employed the mouse system. We found that although the alpha and beta isoforms are present in the mouse, the gamma isoform is not. The alpha isoform protein was detected clearly in most adult tissues, whereas the beta isoform protein was almost undetectable except in spleen, testis, thymus, and lung. On the other hand, mRNAs of both isoforms were detectable in all tissues we examined. High levels of the beta isoform protein was detected in peritoneal exudate macrophage cells in adult mouse as well as in cultured fibroblasts, together with the alpha isoform. The alpha isoform was expressed at a constant level throughout the embryonic stages we examined, whereas the beta isoform protein was detected at the mid-stages of development and increased to levels almost equal to those of the alpha isoform during the late stages of embryogenesis. Therefore, unlike the alpha isoform, expression of the beta isoform protein is restricted in adult tissues. Moreover, we showed that alpha and beta isoforms were colocalized within the same focal adhesion plaques, and cytoplasmic pools of both isoforms exist in the perinuclear area, colocalized with the Golgi apparatus. 相似文献
7.
Rei Endo Kei Matsumoto Hiroshi Shigeno 《Journal of Network and Systems Management》2012,20(3):353-371
Massively Multiplayer Online (MMO) games have large-scale virtual environments. Here, we propose a load distribution technique called the Group Based Load-distribution Technique with Virtual Group (GBLT-VG) that utilizes Peer-to-Peer (P2P) communication to maintain scalability under high user density conditions in MMO virtual environments. A common problem of P2P virtual environments is that user group behavior frequently generates high user density conditions. Existing techniques to manage the virtual environment cannot maintain performance in such high user density situations. The proposed technique, GBLT-VG, reduces area management loads of manager peers by introducing a new manager who manages a user neighbor group. GBLT-VG forms the user neighbor group efficiently by using party function under high user density conditions caused by users?? cooperative behaviors. In addition, GBLT-VG reduce the management load by using a virtual group when a number of parties is small, thereby decreasing the existing managers?? loads dynamically. This paper also presents simulation results demonstrating how GBLT-VG can reduce the average number of users managed by the server. 相似文献
8.
Regulation of lactate production in Streptococcus bovis: A spiraling effect that contributes to rumen acidosis 总被引:1,自引:0,他引:1
When Streptococcus bovis was grown in batch culture with 6 g/L glucose at pH 6.7, maximum specific growth rate was 1.47 h(-1), and lactate was the primary fermentation product. In continuous culture at pH 6.7 and growth rate equal to .10 h(-1), little lactate was formed, and formate, acetate, and ethanol accounted for most of the product. When extra-cellular pH decreased to 4.7, intra-cellular pH declined to 5.4, and organisms switched back to lactate production. Intracellular concentration of fructose 1,6-diphosphate of batch culture cells was greater than 12 mM, a concentration that allowed maximal lactate dehydrogenase activity. When Streptococcus bovis was grown in continuous culture at pH 6.7, intracellular fructose-l,6-diphosphate declined to .4 mM, a concentration which gave little lactate dehydrogenase activity at pH 6.5 or greater. Decreasing pH of continuous culture to 4.7 increased intracellular fructose-1,6-diphosphate concentration to .8 mM. This concentration was still limiting if lactate dehydrogenase was assayed at pH 6.5, but nearly maximal activity was obtained when enzyme was assayed at pH 5.5. The small increase in fructose-l,6-diphosphate and decreased requirement of lactate dehydrogenase for fructose-l,6-diphosphate under acidic assay conditions, accounted for increased lactate production during low pH (4.7) continuous culture. These and other aspects of lactate regulation by Streptococcus bovis are discussed as factors leading to rumen acidosis. This pattern of regulation also helps to explain why rumen acidosis is difficult to reverse. 相似文献
9.
Sean R. Tachibana Longteng Tang Liangdong Zhu Yuka Takeda Keiji Fushimi Yoshibumi Ueda Takahiro Nakajima Yuto Kuwasaki Moritoshi Sato Rei Narikawa Chong Fang 《International journal of molecular sciences》2021,22(10)
Cyanobacteriochromes (CBCRs) are promising optogenetic tools for their diverse absorption properties with a single compact cofactor-binding domain. We previously uncovered the ultrafast reversible photoswitching dynamics of a red/green photoreceptor AnPixJg2, which binds phycocyanobilin (PCB) that is unavailable in mammalian cells. Biliverdin (BV) is a mammalian cofactor with a similar structure to PCB but exhibits redder absorption. To improve the AnPixJg2 feasibility in mammalian applications, AnPixJg2_BV4 with only four mutations has been engineered to incorporate BV. Herein, we implemented femtosecond transient absorption (fs-TA) and ground state femtosecond stimulated Raman spectroscopy (GS-FSRS) to uncover transient electronic dynamics on molecular time scales and key structural motions responsible for the photoconversion of AnPixJg2_BV4 with PCB (Bpcb) and BV (Bbv) cofactors in comparison with the parent AnPixJg2 (Apcb). Bpcb adopts the same photoconversion scheme as Apcb, while BV4 mutations create a less bulky environment around the cofactor D ring that promotes a faster twist. The engineered Bbv employs a reversible clockwise/counterclockwise photoswitching that requires a two-step twist on ~5 and 35 picosecond (ps) time scales. The primary forward Pfr → Po transition displays equal amplitude weights between the two processes before reaching a conical intersection. In contrast, the primary reverse Po → Pfr transition shows a 2:1 weight ratio of the ~35 ps over 5 ps component, implying notable changes to the D-ring-twisting pathway. Moreover, we performed pre-resonance GS-FSRS and quantum calculations to identify the Bbv vibrational marker bands at ~659,797, and 1225 cm−1. These modes reveal a stronger H-bonding network around the BV cofactor A ring with BV4 mutations, corroborating the D-ring-dominant reversible photoswitching pathway in the excited state. Implementation of BV4 mutations in other PCB-binding GAF domains like AnPixJg4, AM1_1870g3, and NpF2164g5 could promote similar efficient reversible photoswitching for more directional bioimaging and optogenetic applications, and inspire other bioengineering advances. 相似文献
10.