Open-celled porous NiAl intermetallics with adjustable pore characteristics and mechanical properties were successfully prepared by using spherical carbamide as space-holders via combustion synthesis.Examinations of m...Open-celled porous NiAl intermetallics with adjustable pore characteristics and mechanical properties were successfully prepared by using spherical carbamide as space-holders via combustion synthesis.Examinations of macroscopic and microscopic morphologies as well as the quasi-static compressive test for the resultant materials were carried out.Depending on the volume fraction and particle size of the carbamide,the porosity and pore size of the porous NiAl intermetallics can be controlled freely in a range of 57.57%-84.58% and 0.4-2.0 mm,respectively.Furthermore,quasi-static compressive tests indicate that the mechanical behavior of the present porous materials is in good agreement with the Gibson-Ashby model.展开更多
Nitrogenous fertilizers of prolonged action were developed on the basis of carbamide （urea）. Technological schemes and parameters are offered to obtain restructured carbamide. Possible versions of degradation of dif...Nitrogenous fertilizers of prolonged action were developed on the basis of carbamide （urea）. Technological schemes and parameters are offered to obtain restructured carbamide. Possible versions of degradation of different structure prolonged action fertilizers are considered. It was shown that the most favorable conditions for degradation of polymer molecules are created when molar ratio of the initial carbamide and aldehyde is within 1：1-1.3, correspondingly. At such terms the linear structure molecules with rare cross-links are formed. Such structure is more accessible for penetration of ureasive ferments into polymer molecules.展开更多
Nitrogen-15 isotope-modified compounds are widely used in medicine, pharmacology, agriculture and various fields of science and their nomenclature is gradually increasing. Their widespread use depends on the availabil...Nitrogen-15 isotope-modified compounds are widely used in medicine, pharmacology, agriculture and various fields of science and their nomenclature is gradually increasing. Their widespread use depends on the availability of inexpensive and simple isotope analysis methods. The present article is an attempt to determine the nitrogen-15 isotope content directly in organic compounds without their conversion. The general principle of possibility of determination of the isotopes of nitrogen directly in organic compounds is proposed. Based on the study of mass-spectra of Carbamide Carbonyldiamide, isocyanic acid and nitrobenzene the mass peaks are selected, by which it is possible to determine the atomic fraction of the isotopes of nitrogen. The respective formulas are proposed.展开更多
基金Project (51072104) supported by the National Natural Science Foundation of ChinaProject (BS2010CL038) supported by the Research Award Fund for Outstanding Young and Middle-aged Scientists of Shandong Province,China
文摘Open-celled porous NiAl intermetallics with adjustable pore characteristics and mechanical properties were successfully prepared by using spherical carbamide as space-holders via combustion synthesis.Examinations of macroscopic and microscopic morphologies as well as the quasi-static compressive test for the resultant materials were carried out.Depending on the volume fraction and particle size of the carbamide,the porosity and pore size of the porous NiAl intermetallics can be controlled freely in a range of 57.57%-84.58% and 0.4-2.0 mm,respectively.Furthermore,quasi-static compressive tests indicate that the mechanical behavior of the present porous materials is in good agreement with the Gibson-Ashby model.
文摘Nitrogenous fertilizers of prolonged action were developed on the basis of carbamide （urea）. Technological schemes and parameters are offered to obtain restructured carbamide. Possible versions of degradation of different structure prolonged action fertilizers are considered. It was shown that the most favorable conditions for degradation of polymer molecules are created when molar ratio of the initial carbamide and aldehyde is within 1：1-1.3, correspondingly. At such terms the linear structure molecules with rare cross-links are formed. Such structure is more accessible for penetration of ureasive ferments into polymer molecules.
文摘Nitrogen-15 isotope-modified compounds are widely used in medicine, pharmacology, agriculture and various fields of science and their nomenclature is gradually increasing. Their widespread use depends on the availability of inexpensive and simple isotope analysis methods. The present article is an attempt to determine the nitrogen-15 isotope content directly in organic compounds without their conversion. The general principle of possibility of determination of the isotopes of nitrogen directly in organic compounds is proposed. Based on the study of mass-spectra of Carbamide Carbonyldiamide, isocyanic acid and nitrobenzene the mass peaks are selected, by which it is possible to determine the atomic fraction of the isotopes of nitrogen. The respective formulas are proposed.
