In this paper,the King’s type modification of(p,q)-Bleimann-Butzer and Hahn operators is defined.Some results based on Korovkin’s approximation theorem for these new operators are studied.With the help of modulus of...In this paper,the King’s type modification of(p,q)-Bleimann-Butzer and Hahn operators is defined.Some results based on Korovkin’s approximation theorem for these new operators are studied.With the help of modulus of continuity and the Lipschitz type maximal functions,the rate of convergence for these new operators are obtained.It is shown that the King’s type modification have better rate of convergence,flexibility than classical(p,q)-BBH operators on some subintervals.Further,for comparisons of the operators,we presented some graphical examples and the error estimation in the form of tables through MATLAB(R2015a)展开更多
Cation exchange capacity (CEC) is an important characteristic of zeolites, especially when they are used as adsorbents in the aqueous system. However, no international standard method exists for the determination of C...Cation exchange capacity (CEC) is an important characteristic of zeolites, especially when they are used as adsorbents in the aqueous system. However, no international standard method exists for the determination of CEC of zeolites. We determined CEC of Linde-type A and Na-P1 type zeolites at various pH (4 to 10) with a simple method, where Na+-saturated zeolites were prepared, and then various amounts of HCl were added. CEC was simply calculated by subtracting the amount of Na+ in the final supernatant from the content of Na+ of the Na+-saturated zeolites. CEC of the zeolites decreased with decreasing pH and with decreasing Na+ concentration of the final supernatant. The concentration of Na+ of the supernatant, CEC of the zeolites began to decrease at weakly alkaline or neutral pH, and that of the Linde-type A zeolite became about half at pH around 6. When CEC was plotted against pH-pNa;where pNa is negative logarithm of the activity of Na+;CEC of each zeolite was expressed by a curve. It indicates that the CEC or the amount of Na+ retention is univocally determined by the ratio of activities of Na+ and proton.展开更多
以端含氢硅油(PHMS)、烯丙基聚氧乙烯聚氧丙烯环氧基醚(APEE)和三乙胺(TEA)为原料,经硅氢加成反应和季铵化开环反应合成了一种阳-非离子型双子有机硅表面活性剂(QAGS)。用红外光谱对QAGS的结构进行了表征,并对QAGS的临界胶束浓度(cmc)...以端含氢硅油(PHMS)、烯丙基聚氧乙烯聚氧丙烯环氧基醚(APEE)和三乙胺(TEA)为原料,经硅氢加成反应和季铵化开环反应合成了一种阳-非离子型双子有机硅表面活性剂(QAGS)。用红外光谱对QAGS的结构进行了表征,并对QAGS的临界胶束浓度(cmc)、表面张力(γcmc)以及耐硬水稳定性等进行了测试。结果表明,QAGS的cmc为1.0 g/L,γcmc为25.7 m N/m,在硬水中的稳定性达5级。展开更多
The novel class of inorganic nanoclusters, \{\[AlO\-4Al\-\{12\}(OH)\-\{24\}(H\-2O)\-\{12\}\]\}\{\[SiW\-\{11\}O\-\{39\}CoCl\]\}\511H\-2O, \{\[AlO\-4Al\-\{12\}(OH)\-\{24\}(H\-2O)\-\{12\}\]\}\{\[P\-2W\-\{18\}O\-\{62\}\]\...The novel class of inorganic nanoclusters, \{\[AlO\-4Al\-\{12\}(OH)\-\{24\}(H\-2O)\-\{12\}\]\}\{\[SiW\-\{11\}O\-\{39\}CoCl\]\}\511H\-2O, \{\[AlO\-4Al\-\{12\}(OH)\-\{24\}(H\-2O)\-\{12\}\]\}\{\[P\-2W\-\{18\}O\-\{62\}\]\}Cl\533H\-2O and \{\[AlO\-4Al\-\{12\}(OH)\-\{24\}(H\-2O)\-\{12\}\]\}\-2\[NaP\-5W\-\{30\}O\-\{110\}\]\524H\-2O, consisting of Keggin cations and heteropolyoxometalates, has been synthesized and characterized by ICP, IR and NMR. It is proved that the intrinsic identities of Keggin cation and heteropolyanions of the clusters are preserved within the gels.展开更多
To further elucidate interaction of nitroaromatic compounds with mineral surface, the sorption of m-dinitrobenzene （m-DNB） and nitrobenzene to original bentonite in aqueous solution containing different electrolytes...To further elucidate interaction of nitroaromatic compounds with mineral surface, the sorption of m-dinitrobenzene （m-DNB） and nitrobenzene to original bentonite in aqueous solution containing different electrolytes （i.e., KCl, NH4Cl, CaCl2 and Tetramethylammonium bromide （TMAB）） was studied. The sorption of m-DNB was greatly enhanced with the presence of KCl and NH4Cl, while little influence was observed with CaCl2 and TMAB, following the order of KCl 〉 NH4Cl 〉〉 TMAB, CaCl2, or DI water. For nitrobenzene, sorption enhancement only occurred at high nitrobenzene concentrations in the presence of KCl, and the solute equilibrium concentration at inflexion point was lowered with increasing KCl concentration. These sorption enhancements were significantly promoted with the increase of electrolyte concentration. The salting-out effect is insufficient to account for the sorption enhancement by original bentonite with increasing KCI or NH4Cl concentration. X-ray diffraction patterns of bentonite suspensions indicated that the sorption enhancement of m-DNB was attributed to the intercalation of K^＋ or NH4^＋ into bentonite interlayer and then dehydration with m-DNB to form inner-sphere complexes, which caused previously expanded bentonite interlayers to collapse in aqueous suspension, thus further enhanced the interaction of phenyl with siloxane surface. In comparison, the sorption enhancement of NB is attributed to the formation of outer-sphere complexes with K^＋ at high solute-loadings （〉 20（0-400 mg/kg）. The sorption of m-DNB to initially modified TMA^＋-bentonite and K^＋-bentonite was almost the same as respective sorption to original bentonite in solution containing TMA^＋ and K^＋.展开更多
文摘In this paper,the King’s type modification of(p,q)-Bleimann-Butzer and Hahn operators is defined.Some results based on Korovkin’s approximation theorem for these new operators are studied.With the help of modulus of continuity and the Lipschitz type maximal functions,the rate of convergence for these new operators are obtained.It is shown that the King’s type modification have better rate of convergence,flexibility than classical(p,q)-BBH operators on some subintervals.Further,for comparisons of the operators,we presented some graphical examples and the error estimation in the form of tables through MATLAB(R2015a)
文摘Cation exchange capacity (CEC) is an important characteristic of zeolites, especially when they are used as adsorbents in the aqueous system. However, no international standard method exists for the determination of CEC of zeolites. We determined CEC of Linde-type A and Na-P1 type zeolites at various pH (4 to 10) with a simple method, where Na+-saturated zeolites were prepared, and then various amounts of HCl were added. CEC was simply calculated by subtracting the amount of Na+ in the final supernatant from the content of Na+ of the Na+-saturated zeolites. CEC of the zeolites decreased with decreasing pH and with decreasing Na+ concentration of the final supernatant. The concentration of Na+ of the supernatant, CEC of the zeolites began to decrease at weakly alkaline or neutral pH, and that of the Linde-type A zeolite became about half at pH around 6. When CEC was plotted against pH-pNa;where pNa is negative logarithm of the activity of Na+;CEC of each zeolite was expressed by a curve. It indicates that the CEC or the amount of Na+ retention is univocally determined by the ratio of activities of Na+ and proton.
文摘以端含氢硅油(PHMS)、烯丙基聚氧乙烯聚氧丙烯环氧基醚(APEE)和三乙胺(TEA)为原料,经硅氢加成反应和季铵化开环反应合成了一种阳-非离子型双子有机硅表面活性剂(QAGS)。用红外光谱对QAGS的结构进行了表征,并对QAGS的临界胶束浓度(cmc)、表面张力(γcmc)以及耐硬水稳定性等进行了测试。结果表明,QAGS的cmc为1.0 g/L,γcmc为25.7 m N/m,在硬水中的稳定性达5级。
文摘The novel class of inorganic nanoclusters, \{\[AlO\-4Al\-\{12\}(OH)\-\{24\}(H\-2O)\-\{12\}\]\}\{\[SiW\-\{11\}O\-\{39\}CoCl\]\}\511H\-2O, \{\[AlO\-4Al\-\{12\}(OH)\-\{24\}(H\-2O)\-\{12\}\]\}\{\[P\-2W\-\{18\}O\-\{62\}\]\}Cl\533H\-2O and \{\[AlO\-4Al\-\{12\}(OH)\-\{24\}(H\-2O)\-\{12\}\]\}\-2\[NaP\-5W\-\{30\}O\-\{110\}\]\524H\-2O, consisting of Keggin cations and heteropolyoxometalates, has been synthesized and characterized by ICP, IR and NMR. It is proved that the intrinsic identities of Keggin cation and heteropolyanions of the clusters are preserved within the gels.
基金supported by the National Natural Science Foundation of China (No. 20577041)the New Century Educational Talents Plan of Chinese Education Ministry (No. NCET-05-0525)+1 种基金the Foundation for the Author of National Excellent Doctoral Dissertation of PR China(No.200765)the Program of Provincial Science and Technology of Zhejiang (No. 2006C33050)
文摘To further elucidate interaction of nitroaromatic compounds with mineral surface, the sorption of m-dinitrobenzene （m-DNB） and nitrobenzene to original bentonite in aqueous solution containing different electrolytes （i.e., KCl, NH4Cl, CaCl2 and Tetramethylammonium bromide （TMAB）） was studied. The sorption of m-DNB was greatly enhanced with the presence of KCl and NH4Cl, while little influence was observed with CaCl2 and TMAB, following the order of KCl 〉 NH4Cl 〉〉 TMAB, CaCl2, or DI water. For nitrobenzene, sorption enhancement only occurred at high nitrobenzene concentrations in the presence of KCl, and the solute equilibrium concentration at inflexion point was lowered with increasing KCl concentration. These sorption enhancements were significantly promoted with the increase of electrolyte concentration. The salting-out effect is insufficient to account for the sorption enhancement by original bentonite with increasing KCI or NH4Cl concentration. X-ray diffraction patterns of bentonite suspensions indicated that the sorption enhancement of m-DNB was attributed to the intercalation of K^＋ or NH4^＋ into bentonite interlayer and then dehydration with m-DNB to form inner-sphere complexes, which caused previously expanded bentonite interlayers to collapse in aqueous suspension, thus further enhanced the interaction of phenyl with siloxane surface. In comparison, the sorption enhancement of NB is attributed to the formation of outer-sphere complexes with K^＋ at high solute-loadings （〉 20（0-400 mg/kg）. The sorption of m-DNB to initially modified TMA^＋-bentonite and K^＋-bentonite was almost the same as respective sorption to original bentonite in solution containing TMA^＋ and K^＋.
