Concretes on the basis of the alumosilicate polymer can be prepared by alkali activation （NaOH, sodium water glass） of waste brown coal fly ash. The preparation is possible： （1） by using a short-term heating of t...Concretes on the basis of the alumosilicate polymer can be prepared by alkali activation （NaOH, sodium water glass） of waste brown coal fly ash. The preparation is possible： （1） by using a short-term heating of the concrete mix （to 80 ℃）; or （2） by allowing the mix to harden spontaneously at a temperature of 20 ℃. The concretes prepared by short-time heating attain high strength values after their preparation; the values are comparable to those characterizing concretes obtained on the basis of Portland cement. The strength development of concretes hardening at 20 ℃ is substantially less steep but, nevertheless, the strength attained after about 60 days is practically identical with that of the concretes exposed to a short-time heating. The shrinkage of concretes prepared by short-time heating is very small as compared with the concretes allowed to harden spontaneously; the shrinkage of latter concretes is larger than that of the concretes on the basis of Portland cement. The concretes on the basis of alumosilicate polymer exhibit much better resistance to the corrosive action of the environment as compared with those prepared on the basis of Portland cement.展开更多
An octameric water moiety which consists of a chairlike water hexamer and two pendent water molecules in the 1,4-diaxial positions and shows a similar structure to the hydrocarbon （lr,4r）-1,4-dimethylcyclohexane, is...An octameric water moiety which consists of a chairlike water hexamer and two pendent water molecules in the 1,4-diaxial positions and shows a similar structure to the hydrocarbon （lr,4r）-1,4-dimethylcyclohexane, is unambiguously trapped in a 2D Cu（II） mixed-ligand coordination polymer, {[Cu2（bpp）2（HzO）2（bpda）2]＇6H2O}n （1） （bpp = 1,3-bis（4-pyridyl）propane and H2bpda = 2,2＇-biphenyldicarboxylic acid）. The water octamer can be extended into a hybrid carboxylate-water decamer when carboxylic oxygen atoms from bpda2- are involved. Interestingly, the present hybrid decamer bears a similar structural topology to a butterfly （H2O）10 cluster. The reversible dehydration/hydration of 1 is determined by X-ray powder diffraction studies.展开更多
Orthogonal arrays (OAs), mixed level or fixed level (asymmetric or symmetric), are useful in the design of various experiments. They are also a fundamental tool in the construction of various combinatorial configurati...Orthogonal arrays (OAs), mixed level or fixed level (asymmetric or symmetric), are useful in the design of various experiments. They are also a fundamental tool in the construction of various combinatorial configurations. In this paper, we establish a general "expansive replacement method" for constructing mixedlevel OAs of an arbitrary strength. As a consequence, a positive answer to the question about orthogonal arrays posed by Hedayat, Sloane and Stufken is given. Some series of mixed level OAs of strength ≥3 are produced.展开更多
基金This study was part of the research project CEZ：MSM 6046137302： ＂Preparation and research of functional materials and material technologies using micro-and nanoscopic methods＂ and Czech Science Foundation Grant 103/08/1639 ＂Microstructure of inorganic alumosilicate polymers＂.
文摘Concretes on the basis of the alumosilicate polymer can be prepared by alkali activation （NaOH, sodium water glass） of waste brown coal fly ash. The preparation is possible： （1） by using a short-term heating of the concrete mix （to 80 ℃）; or （2） by allowing the mix to harden spontaneously at a temperature of 20 ℃. The concretes prepared by short-time heating attain high strength values after their preparation; the values are comparable to those characterizing concretes obtained on the basis of Portland cement. The strength development of concretes hardening at 20 ℃ is substantially less steep but, nevertheless, the strength attained after about 60 days is practically identical with that of the concretes exposed to a short-time heating. The shrinkage of concretes prepared by short-time heating is very small as compared with the concretes allowed to harden spontaneously; the shrinkage of latter concretes is larger than that of the concretes on the basis of Portland cement. The concretes on the basis of alumosilicate polymer exhibit much better resistance to the corrosive action of the environment as compared with those prepared on the basis of Portland cement.
基金supported by the National Natural Science Foundation of China (50971063,21053001)the Natural Science Foundation of Fujian Province (2011J01047,2003F006,2010J01042)+1 种基金the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry of Chinathe Startup Package Funding of Huaqiao University (10BS210 and 11BS102)
文摘An octameric water moiety which consists of a chairlike water hexamer and two pendent water molecules in the 1,4-diaxial positions and shows a similar structure to the hydrocarbon （lr,4r）-1,4-dimethylcyclohexane, is unambiguously trapped in a 2D Cu（II） mixed-ligand coordination polymer, {[Cu2（bpp）2（HzO）2（bpda）2]＇6H2O}n （1） （bpp = 1,3-bis（4-pyridyl）propane and H2bpda = 2,2＇-biphenyldicarboxylic acid）. The water octamer can be extended into a hybrid carboxylate-water decamer when carboxylic oxygen atoms from bpda2- are involved. Interestingly, the present hybrid decamer bears a similar structural topology to a butterfly （H2O）10 cluster. The reversible dehydration/hydration of 1 is determined by X-ray powder diffraction studies.
基金supported by National Natural Science Foundation of China (Grant Nos.11271280 and 10831002)
文摘Orthogonal arrays (OAs), mixed level or fixed level (asymmetric or symmetric), are useful in the design of various experiments. They are also a fundamental tool in the construction of various combinatorial configurations. In this paper, we establish a general "expansive replacement method" for constructing mixedlevel OAs of an arbitrary strength. As a consequence, a positive answer to the question about orthogonal arrays posed by Hedayat, Sloane and Stufken is given. Some series of mixed level OAs of strength ≥3 are produced.
