There are mainly two kinds of equipment to produce synthetic diamond,namely belt press & cubic press.It has been customary in the industry to regard synthetic diamond produced by cubic press is inferior to that ma...There are mainly two kinds of equipment to produce synthetic diamond,namely belt press & cubic press.It has been customary in the industry to regard synthetic diamond produced by cubic press is inferior to that made by belt press.With the on-going improvement in technology,know-how & accumulated experiences, perhaps it’ s time for us to review the qualities & performances of synthetic diamond made by the cubic press more objectively.Studies were carried out on the performances of the two kinds of diamond by choosing from top brands & top qualities,with coarser mesh sizes 20/30 & 30/40.Comparisons were made on parameters, such as TI,TTI,PPC,bulk density,compact,roughness and arealight.And the diamonds chosen were used to produce the relevant diamond core drill bits and saw blades,their respective cutting performances such as cutting efficiency,segments consumption were measured and reported in this paper.The report demonstrates that producing the high quality diamond does not depend on the type of presses(Belt or Cubic) but rather on the know-how,technology and what it is made.展开更多
The paper outlines the background of the research on control of agriculture tridimensional pollution and its tendency.The new concept of agricultural tridimension pollution (ATriP) with its control theory is initiall...The paper outlines the background of the research on control of agriculture tridimensional pollution and its tendency.The new concept of agricultural tridimension pollution (ATriP) with its control theory is initially proposed as a result ofcontinuously increased agricultural pollution within the systems of hydrosphere, pedosphere, biosphere and atmospheredue to improper use of agricultural management measures. Furthermore, the high priority of the next 5-10 years nationalresearch domains and areas, and techniques for strengthening of ATriP prevention and control is discussed.展开更多
A dicarbonyl precursor of 9-hydroxy-cembrene-C,8-tetrahydropyranoxy-3,7,11,15- tetramethyl-14-oxo-2E,6E,10E-hexdecatrienal,was prepared from farnesyl acetate via four steps.
The two new diarylheptanoids, 1,7-bis(4-hydroxyphenyl)-1,4,6 (l) and aecrogenin G (2) were Synthesized starting from 4-hydroxybenzaldehyde (3) and acetone
Synthetic studies on 4-demethyl-qinghaosu involving preparation of key intermediate olefin 5 and its photooxygenation were described. Experiment showed that rearrangement product 11 was formed predominantly instead of...Synthetic studies on 4-demethyl-qinghaosu involving preparation of key intermediate olefin 5 and its photooxygenation were described. Experiment showed that rearrangement product 11 was formed predominantly instead of the desired allylic peroxide 4 during the photooxygenation.展开更多
This paper reports mainly the preparation of silica supported acetylacetone ligands and their cobalt complexes, the characterization of their chemical structure, and the evaluation of their catalytic activity in the r...This paper reports mainly the preparation of silica supported acetylacetone ligands and their cobalt complexes, the characterization of their chemical structure, and the evaluation of their catalytic activity in the reaction for the preparation of ethers directly from alkanols and benzyl chloride. The results indicate that those silica supported β-diketone cobalt complexes (SACO) not only can simplify the reaction procedure of the ether preparation but also show a much higher catalytic activity in comparison with other homogeneous catalysts. In addition, SACO can be recovered and reused although their catalytic activity descend gradually as a result of the decrease in their cobalt content.展开更多
The double oxidative coupling of methyl 8-bromo-3,4-dihydro- xy-5,7-dimethoxy-2-naphthylacetate and its solvent effect are studied. Demethylation followed by methylation or vice versa of dimethyl-2,11-dihy- droxy-4,6,...The double oxidative coupling of methyl 8-bromo-3,4-dihydro- xy-5,7-dimethoxy-2-naphthylacetate and its solvent effect are studied. Demethylation followed by methylation or vice versa of dimethyl-2,11-dihy- droxy-4,6,7,9-tetramethoxy-3,10-perylenequinone-1,12-diacetate can be effected regioselectively and amenable to natural product synthesis.展开更多
文摘There are mainly two kinds of equipment to produce synthetic diamond,namely belt press & cubic press.It has been customary in the industry to regard synthetic diamond produced by cubic press is inferior to that made by belt press.With the on-going improvement in technology,know-how & accumulated experiences, perhaps it’ s time for us to review the qualities & performances of synthetic diamond made by the cubic press more objectively.Studies were carried out on the performances of the two kinds of diamond by choosing from top brands & top qualities,with coarser mesh sizes 20/30 & 30/40.Comparisons were made on parameters, such as TI,TTI,PPC,bulk density,compact,roughness and arealight.And the diamonds chosen were used to produce the relevant diamond core drill bits and saw blades,their respective cutting performances such as cutting efficiency,segments consumption were measured and reported in this paper.The report demonstrates that producing the high quality diamond does not depend on the type of presses(Belt or Cubic) but rather on the know-how,technology and what it is made.
文摘The paper outlines the background of the research on control of agriculture tridimensional pollution and its tendency.The new concept of agricultural tridimension pollution (ATriP) with its control theory is initially proposed as a result ofcontinuously increased agricultural pollution within the systems of hydrosphere, pedosphere, biosphere and atmospheredue to improper use of agricultural management measures. Furthermore, the high priority of the next 5-10 years nationalresearch domains and areas, and techniques for strengthening of ATriP prevention and control is discussed.
文摘A dicarbonyl precursor of 9-hydroxy-cembrene-C,8-tetrahydropyranoxy-3,7,11,15- tetramethyl-14-oxo-2E,6E,10E-hexdecatrienal,was prepared from farnesyl acetate via four steps.
文摘The two new diarylheptanoids, 1,7-bis(4-hydroxyphenyl)-1,4,6 (l) and aecrogenin G (2) were Synthesized starting from 4-hydroxybenzaldehyde (3) and acetone
文摘Synthetic studies on 4-demethyl-qinghaosu involving preparation of key intermediate olefin 5 and its photooxygenation were described. Experiment showed that rearrangement product 11 was formed predominantly instead of the desired allylic peroxide 4 during the photooxygenation.
文摘This paper reports mainly the preparation of silica supported acetylacetone ligands and their cobalt complexes, the characterization of their chemical structure, and the evaluation of their catalytic activity in the reaction for the preparation of ethers directly from alkanols and benzyl chloride. The results indicate that those silica supported β-diketone cobalt complexes (SACO) not only can simplify the reaction procedure of the ether preparation but also show a much higher catalytic activity in comparison with other homogeneous catalysts. In addition, SACO can be recovered and reused although their catalytic activity descend gradually as a result of the decrease in their cobalt content.
文摘The double oxidative coupling of methyl 8-bromo-3,4-dihydro- xy-5,7-dimethoxy-2-naphthylacetate and its solvent effect are studied. Demethylation followed by methylation or vice versa of dimethyl-2,11-dihy- droxy-4,6,7,9-tetramethoxy-3,10-perylenequinone-1,12-diacetate can be effected regioselectively and amenable to natural product synthesis.
