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931.
联图Fn∨Pm的邻点可区别全染色 总被引:6,自引:0,他引:6
设G(V,E)是阶数至少为2的简单连通图,k是正整数,V∪E到{1,2,3,…k}的映射f满足:对任意uv,uw∈E(G),u≠w,有f(uv)≠f(vw);对任意uv∈E(G),有f(u)≠f(v), f(u)≠f(uv),f(v)≠f(uv);那么称f为G的k-正常全染色,若f还满足对任意uv∈E(G),有G(u)≠C(v),其中C(u)={f(u)}∪{f(uv)|uv∈E(G),v∈V(G)}那么称f为G的k-邻点可区别的全染色(简记为k-AVDTC),称min{k|G有k-邻点可区别的全染色}为G的邻点可区别的全色数,记作Xat(G).本文得到了联图Fn∨Pm的全色数. 相似文献
932.
933.
开式和闭式离心泵进口回流的研究 总被引:6,自引:1,他引:5
利用毕托管对闭式和开式不同叶顶间隙的离心泵叶轮进口流场进行了动态测试,另外对开式叶轮吸入盖上的静压分布也进行了动态测试,并对叶轮流道内流场进行了可视化观察,弄清了小流量工况下叶片间的回流分布情况及上述不同叶轮对回流发生的影响及其原因。 相似文献
934.
The femtosecond time-resolved two-photon photoemission (TR-2PP) and the ultra high vacuum (UHV) surface science techniques
are integrated to investigate the electronic structures and the interfacial electron transfer dynamics at the atomically ordered
adsorbate overlayers on TiO2 singlecrystalline surfaces. Our research into the CH3OH/TiO2 system exhibits complex dynamics, providing abundant information with regard to electron transport and solvation processes
in the interfacial solvent structures. These represent the fundamentally physical, photochemical, and photocatalytic reactions
of protic chemicals covered with metal-oxides.
相似文献
935.
936.
937.
Artibano Micali 《代数通讯》2013,41(8):2371-2385
We extend the concept of the “join” to the case of infinitely many weighted algebras. We study the problem of its uniqueness (up to weighted isomorphism) which gives rise to a natural notion of homogeneous weighted algebras. We show that several classes of weighted algebras coming from genetics are homogeneous and that homogeneity is preserved by duplication. Finally, we examine some well-known weighted algebras satisfying identities, as Bernstein, train, and evolution algebras. 相似文献
938.
939.
将N,N′-二甲基乙酰胺(DMAc)作为共试剂添加在间苯二胺水溶液中参与界面聚合反应, 以改善聚酰胺复合反渗透膜(PA-RO-x, x代表添加DMAc的质量分数)的性能. X射线光电子能谱(XPS)和衰减全反射傅里叶红外光谱(ATR-FTIR)分析表明, 随着DMAc含量的增加, 复合膜结构中交联聚酰胺含量相对于线性羧基部分有所增加; 场发射扫描电子显微镜(FE-SEM)和原子力显微镜(AFM)表征结果显示, 随着DMAc含量的增加, 膜表面的粗糙程度逐渐增大; 静态水接触角测试结果表明, 添加DMAc后, 膜的亲水性增强. 结合上述测试结果发现, 添加DMAc可以有效降低水油两相的不相溶性, 提高水相中间苯二胺向正己烷中扩散的速率, 这有助于加快间苯二胺与均苯三甲酰氯反应; 同时, 聚酰胺结构中交联酰胺含量的增加可以提供更多的氢键位点, 有助于水分子快速渗透通过复合膜而不损失截盐率; 膜表面的粗糙程度变大, 有助于提高水通量. 在2 g/L的氯化钠溶液和1.6 MPa测试压力条件下, PA-RO-5.2(DMAc添加质量分数为5.2%)的渗透通量和截盐率分别为66.1 L/(m2·h)和98.7%, 与未添加DMAc的聚酰胺复合反渗透膜相比, 通量增加115%, 截盐率仅下降0.9%. 相似文献
940.
Ahmet Halil Avci Cdric Van Goethem Timon Rijnaarts Sergio Santoro Marco Aquino Gianluca Di Profio Ivo F. J. Vankelecom Wiebe M. De Vos Enrica Fontananova Efrem Curcio 《Molecules (Basel, Switzerland)》2021,26(2)
In this study, novel asymmetric integral cation exchange membranes were prepared by the wet phase inversion of sulfonated polysulfone (SPSf) solutions. SPSf with different degrees of sulfonation (DS) was synthesized by variation in the amount of chlorosulfonic acid utilized as a sulfonating agent. The characterization of SPSf samples was performed using FTIR and 1H-NMR techniques. SPSf with a DS of 0.31 (0.67 meq/g corresponding ion exchange capacity) was chosen to prepare the membranes, as polymers with a higher DS resulted in poor mechanical properties and excessive swelling in water. By a systematic study, the opportunity to tune the properties of SPSf membranes by acting on the composition of the polymeric solution was demonstrated. The effect of two different phase inversion parameters, solvent type and co-solvent ratio, were investigated by morphological and electrochemical characterization. The best properties (permselectivity of 0.86 and electrical resistance of 6.3 Ω∙cm2) were obtained for the membrane prepared with 2-propanol (IPA):1-Methyl-2-pyrrolidinone (NMP) in a 20:80 ratio. This membrane was further characterized in different solution concentrations to estimate its performance in a Reverse Electrodialysis (RED) operation. Although the estimated generated power was less than that of the commercial CMX (Neosepta) membrane, used as a benchmark, the tailor-made membrane can be considered as a cost-effective alternative, as one of the main limitations to the commercialization of RED is the high membrane price. 相似文献