Coalification temperatures are often considered to be approximately 100-170 ℃ for bituminous coal and 170-275 ℃ for anthracite. However, our micropetrographic observations, solid state ^27Al magic-angle spinning nuc...Coalification temperatures are often considered to be approximately 100-170 ℃ for bituminous coal and 170-275 ℃ for anthracite. However, our micropetrographic observations, solid state ^27Al magic-angle spinning nuclear magnetic resonance measurements, interpretation of δ^13C values for whewellite in pelosiderite concretions from Carboniferous sediments, and assessment of whewellite thermal stability show that coalification temperatures can be significantly lower. Also the temperatures of coal alteration may be substantially lower than is stated. Ordinarily, high- temperature alteration is reported, but microthermometric measurements of fluids temperatures and micropetrographic observations show that the coal alteration can take place at low temperatures. For this reason, coals from the Kladno- Rakovnik Basin, part of Late Paleozoic continental basins of the Czech Republic, were analyzed. Regarding coalification, micropetrographic characterizations of unaltered coals, the presence of thermally unstable Al complexes in the coal organic mass documented using ^27Al MAS NMR method, and proven occurrence of whewellite in pelosiderite concretions suggest a lower coalification temperature, max. -70 ℃. Regarding coal alteration, micropetrographic observations revealed （a） the weaker intensity of fluorescence of liptinite, （b） mylonitic structures and microbreccia with carbonate fluid penetration, and （c） high oxygen content in coals （37-38 wt.%）. These phenomena are typical for thermal and oxidative alteration of coal. As the temperature of carbonate fluids inferred from fluid inclusion analysis was evaluated as -100-113 ℃, the temperature of coal alteration was suggested as -113℃; the alteration was caused by hot hydrothermal fluids.展开更多
In this paper, turbulent data obtained from the Damxung site during the Secondary Tibetan Plateau Science Experiment (TIPEX) in 1998 are used to study the characteristics of the turbulent spectra, turbulence transport...In this paper, turbulent data obtained from the Damxung site during the Secondary Tibetan Plateau Science Experiment (TIPEX) in 1998 are used to study the characteristics of the turbulent spectra, turbulence transport, and the dissipation rates of turbulent kinetic energy, temperature variance, and humidity variance in the middle area of the Tibetan Plateau. The turbulent spectra of wind velocity, potential temperature, and humidity satisfy the-2/3 power law in the high frequency range. Horizontal transportation of heat and water vapor is negligible compared with vertical transportation under strong unstable conditions, and as the stability parameter z/L increases (where z is the observational height, and L is the Monin Obukhov length), horizontal transportation becomes dominant under near-neutral, neutral, and stable conditions. The non-dimensional temperature and humidity variances are 20% less than the temperature and humidity gradient variances. These deficits appear to increase as the absolute stability parameter increases. Moreover, the effects of turbulence transportation and pressure variance exist throughout the entire stability region.展开更多
The authors examined the thermal change in the aroma profile of myrrh. The fresh odor of raw myrrh and its hexane extract depended on the amount of （E）-13-ocimene. Myrrh was extracted with hexane to avoid inducing c...The authors examined the thermal change in the aroma profile of myrrh. The fresh odor of raw myrrh and its hexane extract depended on the amount of （E）-13-ocimene. Myrrh was extracted with hexane to avoid inducing changes in the constituents and odor. The main constituent, （E）-L3-ocimene （group A; low boiling point）, and the other constituents （group B; high boiling point） of the hexane extract were separated by bulb-to-bulb distillation. The constituents of groups A and B were analyzed over time by nuclear magnetic resonance analysis and the odors were evaluated. Myrrh＇s odor depended on both the amount of thermally unstable （E）-[3-ocimene, which contributed to the fresh odor, and the constituents of group B （thermally stable）, which contributed to the myrrh-like odor. Six compounds （c^-santalene, （Z）-a-bisabolene, c^-bergamotene, （E）-ct-santalal, c^-photosantalol and campherenol） were isolated from group B. No individual group B component had a myrrh-like odor, although the combined odor of group B was myrrh like. The authors demonstrated that the aroma profile of myrrh depends on the thermal instability of （E）-^-ocimene and a combination of six thermally stable terpenes with similar molecular structures.展开更多
文摘Coalification temperatures are often considered to be approximately 100-170 ℃ for bituminous coal and 170-275 ℃ for anthracite. However, our micropetrographic observations, solid state ^27Al magic-angle spinning nuclear magnetic resonance measurements, interpretation of δ^13C values for whewellite in pelosiderite concretions from Carboniferous sediments, and assessment of whewellite thermal stability show that coalification temperatures can be significantly lower. Also the temperatures of coal alteration may be substantially lower than is stated. Ordinarily, high- temperature alteration is reported, but microthermometric measurements of fluids temperatures and micropetrographic observations show that the coal alteration can take place at low temperatures. For this reason, coals from the Kladno- Rakovnik Basin, part of Late Paleozoic continental basins of the Czech Republic, were analyzed. Regarding coalification, micropetrographic characterizations of unaltered coals, the presence of thermally unstable Al complexes in the coal organic mass documented using ^27Al MAS NMR method, and proven occurrence of whewellite in pelosiderite concretions suggest a lower coalification temperature, max. -70 ℃. Regarding coal alteration, micropetrographic observations revealed （a） the weaker intensity of fluorescence of liptinite, （b） mylonitic structures and microbreccia with carbonate fluid penetration, and （c） high oxygen content in coals （37-38 wt.%）. These phenomena are typical for thermal and oxidative alteration of coal. As the temperature of carbonate fluids inferred from fluid inclusion analysis was evaluated as -100-113 ℃, the temperature of coal alteration was suggested as -113℃; the alteration was caused by hot hydrothermal fluids.
基金support of the National Natural Science Foundation of China(41075005)the Research Fund for the Doctoral Program of Higher Education(20110001130010)R&D Special Fund for Public Welfare Industry (Meteorology) by Ministry of Finance and Ministry of Science and Technology(GYHY201006014) in the present study
文摘In this paper, turbulent data obtained from the Damxung site during the Secondary Tibetan Plateau Science Experiment (TIPEX) in 1998 are used to study the characteristics of the turbulent spectra, turbulence transport, and the dissipation rates of turbulent kinetic energy, temperature variance, and humidity variance in the middle area of the Tibetan Plateau. The turbulent spectra of wind velocity, potential temperature, and humidity satisfy the-2/3 power law in the high frequency range. Horizontal transportation of heat and water vapor is negligible compared with vertical transportation under strong unstable conditions, and as the stability parameter z/L increases (where z is the observational height, and L is the Monin Obukhov length), horizontal transportation becomes dominant under near-neutral, neutral, and stable conditions. The non-dimensional temperature and humidity variances are 20% less than the temperature and humidity gradient variances. These deficits appear to increase as the absolute stability parameter increases. Moreover, the effects of turbulence transportation and pressure variance exist throughout the entire stability region.
文摘The authors examined the thermal change in the aroma profile of myrrh. The fresh odor of raw myrrh and its hexane extract depended on the amount of （E）-13-ocimene. Myrrh was extracted with hexane to avoid inducing changes in the constituents and odor. The main constituent, （E）-L3-ocimene （group A; low boiling point）, and the other constituents （group B; high boiling point） of the hexane extract were separated by bulb-to-bulb distillation. The constituents of groups A and B were analyzed over time by nuclear magnetic resonance analysis and the odors were evaluated. Myrrh＇s odor depended on both the amount of thermally unstable （E）-[3-ocimene, which contributed to the fresh odor, and the constituents of group B （thermally stable）, which contributed to the myrrh-like odor. Six compounds （c^-santalene, （Z）-a-bisabolene, c^-bergamotene, （E）-ct-santalal, c^-photosantalol and campherenol） were isolated from group B. No individual group B component had a myrrh-like odor, although the combined odor of group B was myrrh like. The authors demonstrated that the aroma profile of myrrh depends on the thermal instability of （E）-^-ocimene and a combination of six thermally stable terpenes with similar molecular structures.
