The pyrolysis characteristics of PVC were systematically investigated using a Netzschne TG thermo-balance coupled to a quadrupole mass spectrometer. The pyrolysis conditions were 0.1 MPa of Ar, a heating rate of 10 ℃...The pyrolysis characteristics of PVC were systematically investigated using a Netzschne TG thermo-balance coupled to a quadrupole mass spectrometer. The pyrolysis conditions were 0.1 MPa of Ar, a heating rate of 10 ℃/min and a final temperature of 1000℃. Both the thermogravimetric properties and the simultaneous evolution of gaseous products during pyrolysis were studied. The TG/DTG results showed that as the pyrolysis temperature increases the weight loss and weight loss rate of PVC increases. Near 412℃ the weight loss rate attained its peak value. At higher temperatures the rate of loss gradually decreases. The gases evolved during thermogravimetric analysis were analyzed by a mass spectrometer, monitoring the relative intensity of HC1, C6H6, light hydrocarbon and chlorine-containing gases The evolution curves showed that HC1, C6H6, light hydrocarbon and chlorine-containing gases all peak at about 416℃. This is consistent with the fact that the weight loss curves also peak at about 412℃. The extensive HCl evolution is consistent with the high chlorine content of PVC. The formation of these gases can be explained by considering these reactions： dehydrochlorination, intramolecular cyclization and the addition of HCl to unsaturated hydrocarbons.展开更多
The validation and assessment of Envisat advanced synthetic aperture radar (ASAR) ocean wave spectra products are important to their application in ocean wave numerical predictions. Six-year ASAR wave spectra data are...The validation and assessment of Envisat advanced synthetic aperture radar (ASAR) ocean wave spectra products are important to their application in ocean wave numerical predictions. Six-year ASAR wave spectra data are compared with one-dimensional (1D) wave spectra of 55 co-located moored buoy observations in the northern Pacific Ocean. The ASAR wave spectra data are firstly quality control filtered and spatio-temporal matched with buoy data. The comparisons are then performed in terms of 1D wave spectra, significant wave height (SWH) and mean wave period (MWP) in different spatio-temporal offsets respectively. SWH comparison results show the evident dependence of SWH biases on wind speed and the ASAR SWH saturation effect. The ASAR wave spectra tend to underestimate SWH at high wind speeds and overestimate SWH at low wind speeds. MWP comparison results show that MWP has a systematic bias and therefore it should be bias-modified before used. The comparisons of 1D wave spectra show that both wave spectra agree better at low frequencies than at high frequencies, which indicates the ASAR data cannot resolve the high frequency waves.展开更多
Sweetpotato starch thermal properties and its noodle quality were analyzed using a rapid predictive method based on near-infrared spectroscopy （NIRS）. This method was established based on a total of 93 sweetpotato g...Sweetpotato starch thermal properties and its noodle quality were analyzed using a rapid predictive method based on near-infrared spectroscopy （NIRS）. This method was established based on a total of 93 sweetpotato genotypes with diverse genetic background. Starch samples were scanned by NIRS and analyzed for quality properties by reference methods. Results of statistical modelling indicated that NIRS was reasonably accurate in predicting gelatinization onset temperature （To） （standard error of prediction SEP=2.014 ℃, coefficient of determination RSQ=0.85）, gelatinization peak temperature （Tp） （SEP=-1.371 ℃, RSQ=0.89）, gelatinization temperature range （Tr） （SEP=2.234 ℃, RSQ=0.86）, and cooling resistance （CR） （SEP=0.528, RSQ=0.89）. Gelatinization completion temperature （To）, enthalpy of gelatinization （△H）, cooling loss （CL） and swelling degree （SWD）, were modelled less well with RSQ between 0.63 and 0.84. The present results suggested that the NIRS based method was sufficiently accurate and practical for routine analysis of sweetpotato starch and its noodle quality.展开更多
Using the method of Singular Spectrum Analysis (SSA), the evolution regularity of tropical cyclo- nes landing in Guangdong are analyzed. The main periods of yearly topical cyclones landing in Guangdong are found at 8 ...Using the method of Singular Spectrum Analysis (SSA), the evolution regularity of tropical cyclo- nes landing in Guangdong are analyzed. The main periods of yearly topical cyclones landing in Guangdong are found at 8 and quasi-3 years, and in the west of Pearl River Mouth are 12 and quasi-2 years to the west of Pearl River Mouth. The northwest Pacific that topical cyclones are generated is divided into 8 areas, and the SeaSur- face Temperature (SST) in each area is analyzed using SSA. The main periods of NINO-west are 8 and 3 years, and those of the warm pool are 12 and 2 years, respectively. This may be the physical reason for the generation tropical cyclones landing in Guangdong. By combining the Maximum Entropy Method (MEM) with SSA (SSA- MEM), the yearly variation trend of tropical cyclones landing in Guangdong and the Pearl River Mouth are force- ast, and the results are good. The method can be used in operational short-range climate forecast.展开更多
基金Project 2005BS09003 supported by Shandong Province Foundation for Distinguished Young Scholars
文摘The pyrolysis characteristics of PVC were systematically investigated using a Netzschne TG thermo-balance coupled to a quadrupole mass spectrometer. The pyrolysis conditions were 0.1 MPa of Ar, a heating rate of 10 ℃/min and a final temperature of 1000℃. Both the thermogravimetric properties and the simultaneous evolution of gaseous products during pyrolysis were studied. The TG/DTG results showed that as the pyrolysis temperature increases the weight loss and weight loss rate of PVC increases. Near 412℃ the weight loss rate attained its peak value. At higher temperatures the rate of loss gradually decreases. The gases evolved during thermogravimetric analysis were analyzed by a mass spectrometer, monitoring the relative intensity of HC1, C6H6, light hydrocarbon and chlorine-containing gases The evolution curves showed that HC1, C6H6, light hydrocarbon and chlorine-containing gases all peak at about 416℃. This is consistent with the fact that the weight loss curves also peak at about 412℃. The extensive HCl evolution is consistent with the high chlorine content of PVC. The formation of these gases can be explained by considering these reactions： dehydrochlorination, intramolecular cyclization and the addition of HCl to unsaturated hydrocarbons.
基金Supported by the Special Fund for Marine Commonweal Scientific Research of China (No.200705027)
文摘The validation and assessment of Envisat advanced synthetic aperture radar (ASAR) ocean wave spectra products are important to their application in ocean wave numerical predictions. Six-year ASAR wave spectra data are compared with one-dimensional (1D) wave spectra of 55 co-located moored buoy observations in the northern Pacific Ocean. The ASAR wave spectra data are firstly quality control filtered and spatio-temporal matched with buoy data. The comparisons are then performed in terms of 1D wave spectra, significant wave height (SWH) and mean wave period (MWP) in different spatio-temporal offsets respectively. SWH comparison results show the evident dependence of SWH biases on wind speed and the ASAR SWH saturation effect. The ASAR wave spectra tend to underestimate SWH at high wind speeds and overestimate SWH at low wind speeds. MWP comparison results show that MWP has a systematic bias and therefore it should be bias-modified before used. The comparisons of 1D wave spectra show that both wave spectra agree better at low frequencies than at high frequencies, which indicates the ASAR data cannot resolve the high frequency waves.
基金Project supported by the Hi-Tech Research and Development Pro-gram (863) of China (No. 2004AA241180), and the Scientific Re-search Foundation for the Returned Overseas Chinese Scholars of State Education Ministry, and the Science and Technology Depart-ment of Zhejiang Province, China
文摘Sweetpotato starch thermal properties and its noodle quality were analyzed using a rapid predictive method based on near-infrared spectroscopy （NIRS）. This method was established based on a total of 93 sweetpotato genotypes with diverse genetic background. Starch samples were scanned by NIRS and analyzed for quality properties by reference methods. Results of statistical modelling indicated that NIRS was reasonably accurate in predicting gelatinization onset temperature （To） （standard error of prediction SEP=2.014 ℃, coefficient of determination RSQ=0.85）, gelatinization peak temperature （Tp） （SEP=-1.371 ℃, RSQ=0.89）, gelatinization temperature range （Tr） （SEP=2.234 ℃, RSQ=0.86）, and cooling resistance （CR） （SEP=0.528, RSQ=0.89）. Gelatinization completion temperature （To）, enthalpy of gelatinization （△H）, cooling loss （CL） and swelling degree （SWD）, were modelled less well with RSQ between 0.63 and 0.84. The present results suggested that the NIRS based method was sufficiently accurate and practical for routine analysis of sweetpotato starch and its noodle quality.
基金Research on Short-Term Climate Systems--a key project in the 9th -five year economic de- velopment plan (96-908-05-07)
文摘Using the method of Singular Spectrum Analysis (SSA), the evolution regularity of tropical cyclo- nes landing in Guangdong are analyzed. The main periods of yearly topical cyclones landing in Guangdong are found at 8 and quasi-3 years, and in the west of Pearl River Mouth are 12 and quasi-2 years to the west of Pearl River Mouth. The northwest Pacific that topical cyclones are generated is divided into 8 areas, and the SeaSur- face Temperature (SST) in each area is analyzed using SSA. The main periods of NINO-west are 8 and 3 years, and those of the warm pool are 12 and 2 years, respectively. This may be the physical reason for the generation tropical cyclones landing in Guangdong. By combining the Maximum Entropy Method (MEM) with SSA (SSA- MEM), the yearly variation trend of tropical cyclones landing in Guangdong and the Pearl River Mouth are force- ast, and the results are good. The method can be used in operational short-range climate forecast.
