The monthly mean temperature for October in the Fenglin National Natural Reserve of Wuying, in Heilongjiang province, was reconstructed for the period running from 1796 to 2004 using RES tree ring chronology. The expl...The monthly mean temperature for October in the Fenglin National Natural Reserve of Wuying, in Heilongjiang province, was reconstructed for the period running from 1796 to 2004 using RES tree ring chronology. The explained variance of the reconstruction is 34.8%. In the past 209 years, there are 4 colder and 4 warmer periods according to the reconstructed series. A period of 3.33-year is found significant based on the power spectrum method. Abrupt changes are also detected in the reconstructed series with 30-year time scale based on the smoothing t-test, smoothing F-test and Le Page test methods. Significant abrupt changes in mean value are observed for around 1871 and 1900, and a significant abrupt change in standard deviation is observed for around 1851.展开更多
[ Objective] The aim was to establish a method for the determination of Rhodamine B in food by HPLC-UV. [ Metkod] Rhodamine B was extracted with acetone/hexane from food samples. After concentrated and purified by alu...[ Objective] The aim was to establish a method for the determination of Rhodamine B in food by HPLC-UV. [ Metkod] Rhodamine B was extracted with acetone/hexane from food samples. After concentrated and purified by alumina cartridge, the Rhodamine B content in the food was determined by using high performance liquid chromatography with ultraviolet visible detector. [ Result] Within tile concentration range of 0.005 - 2.000 mg/kg, the peak area of Rhodamine B presented good linear relation with the concentration, and the related coefficient was 0.999 98. With high average recovery rate, the detection limit of the method was 0.005 mg/kg[ Concision] It is a fast and accurate method with high sensitivity to detect Rhodamine B in food.展开更多
Here we propose a method for determination of Avermectin residual content in milk and beef content. After extracting and processing the sample, use high performance liquid chromatography （HPLC） for determination. Mo...Here we propose a method for determination of Avermectin residual content in milk and beef content. After extracting and processing the sample, use high performance liquid chromatography （HPLC） for determination. Mobile phase is： V（Methanol）： V（Water）=90： 10; determination wavelength is 245 nm; flow rate is 0.8 mL/min. Avermectin is completely separated in 17min, linear range is 5 - 0.3 g/L, correlation coefficient is 0.9997, average recovery rates of Avermectin in milk and beef are respectively 91.20 %- 100.32 % and 89.93 %-99.15 %, the relative standard deviations are respectively less than 7% and 4%. This method is simple, sensitive and accurate, so is suitable for determination of Avermectin residues in milk and beef, and it can meet domestic and foreign testing requirements.展开更多
[ Objective] The aim was to study the chemical component of volatile oil of garlic in different districts. [ Method] GC-MS was used to an- alyze the composition of the garlic volatile oil in Guiyang, Guizhou Majiang, ...[ Objective] The aim was to study the chemical component of volatile oil of garlic in different districts. [ Method] GC-MS was used to an- alyze the composition of the garlic volatile oil in Guiyang, Guizhou Majiang, Shandong, Yunnan and Chongqing and the HPLC method was used to assay the content of gadicin. [ Result]Gadicin in different essential oil had the highest content but varied a lot. The sampling amount of garlicin be- tween 0.562 and 2.810 μg was in a good linear relation （R =0.999 2, n = 5 ） with peak area, the average recovery rate was 99.39, RSD = 1.76%. [ Conclusion] GC-MS can be used to analysis the composition of essential oil quickly and effectively. The liquid chromatographic analysis of garlicin was simple, reliable and reproducible. The study provided the theoretical basis for selecting garlic in gadic flavor oil production and improving quality of gadicin oil.展开更多
These problems of nonlinearity, fuzziness and few labeled data were rarely considered in traditional remote sensing image classification. A semi-supervised kernel fuzzy C-means （SSKFCM） algorithm is proposed to over...These problems of nonlinearity, fuzziness and few labeled data were rarely considered in traditional remote sensing image classification. A semi-supervised kernel fuzzy C-means （SSKFCM） algorithm is proposed to overcome these disadvantages of remote sensing image classification in this paper. The SSKFCM algorithm is achieved by introducing a kernel method and semi-supervised learning technique into the standard fuzzy C-means （FCM） algorithm. A set of Beijing-1 micro-satellite＇s multispectral images are adopted to be classified by several algorithms, such as FCM, kernel FCM （KFCM）, semi-supervised FCM （SSFCM） and SSKFCM. The classification results are estimated by corresponding indexes. The results indicate that the SSKFCM algorithm significantly improves the classification accuracy of remote sensing images compared with the others.展开更多
The Erlitou site is located at Yanshi City,Henan Province.This site is a large settlement site of Erlitou culture,and it is dated to 3800-3500 a BP.Five kinds of domestic animals,i.e.,dogs,pigs,sheep,goats,and cattle ...The Erlitou site is located at Yanshi City,Henan Province.This site is a large settlement site of Erlitou culture,and it is dated to 3800-3500 a BP.Five kinds of domestic animals,i.e.,dogs,pigs,sheep,goats,and cattle were found from the site.In this paper,two problems have emerged in studies involving the estimation of local isotope levels and the distinction of migrants from locals.Tooth enamel samples from 17 domestic animals individuals were analyzed for strontium isotope ratio(87Sr/86Sr),by the thermal ionization mass spectrometry,including 10 pigs,5 sheep and 2 cattle.The results show that the mean 87Sr/86Sr ratios of 10 pigs enamel samples were 0.712078,Based on the local strontium isotopes ratio range determined by the mean 87Sr/86Sr ratios ±2 of 10 pig enamel samples(0.712256-0.711900),we found that five sheep and one cattle from the Erlitou site fell well outside the local strontium isotopes ratio range and were considered to be non-local.展开更多
基金supported by the Special Research Program for Public-welfare Forestry(No. 200804001)National Science and Technology Support Program(No.2007BAC29B01)the Natural Science Foundation of China(No.40705032)
文摘The monthly mean temperature for October in the Fenglin National Natural Reserve of Wuying, in Heilongjiang province, was reconstructed for the period running from 1796 to 2004 using RES tree ring chronology. The explained variance of the reconstruction is 34.8%. In the past 209 years, there are 4 colder and 4 warmer periods according to the reconstructed series. A period of 3.33-year is found significant based on the power spectrum method. Abrupt changes are also detected in the reconstructed series with 30-year time scale based on the smoothing t-test, smoothing F-test and Le Page test methods. Significant abrupt changes in mean value are observed for around 1871 and 1900, and a significant abrupt change in standard deviation is observed for around 1851.
文摘[ Objective] The aim was to establish a method for the determination of Rhodamine B in food by HPLC-UV. [ Metkod] Rhodamine B was extracted with acetone/hexane from food samples. After concentrated and purified by alumina cartridge, the Rhodamine B content in the food was determined by using high performance liquid chromatography with ultraviolet visible detector. [ Result] Within tile concentration range of 0.005 - 2.000 mg/kg, the peak area of Rhodamine B presented good linear relation with the concentration, and the related coefficient was 0.999 98. With high average recovery rate, the detection limit of the method was 0.005 mg/kg[ Concision] It is a fast and accurate method with high sensitivity to detect Rhodamine B in food.
文摘Here we propose a method for determination of Avermectin residual content in milk and beef content. After extracting and processing the sample, use high performance liquid chromatography （HPLC） for determination. Mobile phase is： V（Methanol）： V（Water）=90： 10; determination wavelength is 245 nm; flow rate is 0.8 mL/min. Avermectin is completely separated in 17min, linear range is 5 - 0.3 g/L, correlation coefficient is 0.9997, average recovery rates of Avermectin in milk and beef are respectively 91.20 %- 100.32 % and 89.93 %-99.15 %, the relative standard deviations are respectively less than 7% and 4%. This method is simple, sensitive and accurate, so is suitable for determination of Avermectin residues in milk and beef, and it can meet domestic and foreign testing requirements.
基金Supported by Industrial Development Plan of Science and Technology Bureau in Guizhou Province[Guizhou Science GY(20103043)]
文摘[ Objective] The aim was to study the chemical component of volatile oil of garlic in different districts. [ Method] GC-MS was used to an- alyze the composition of the garlic volatile oil in Guiyang, Guizhou Majiang, Shandong, Yunnan and Chongqing and the HPLC method was used to assay the content of gadicin. [ Result]Gadicin in different essential oil had the highest content but varied a lot. The sampling amount of garlicin be- tween 0.562 and 2.810 μg was in a good linear relation （R =0.999 2, n = 5 ） with peak area, the average recovery rate was 99.39, RSD = 1.76%. [ Conclusion] GC-MS can be used to analysis the composition of essential oil quickly and effectively. The liquid chromatographic analysis of garlicin was simple, reliable and reproducible. The study provided the theoretical basis for selecting garlic in gadic flavor oil production and improving quality of gadicin oil.
基金Supported by the National High Technology Research and Development Programme （No.2007AA12Z227） and the National Natural Science Foundation of China （No.40701146）.
文摘These problems of nonlinearity, fuzziness and few labeled data were rarely considered in traditional remote sensing image classification. A semi-supervised kernel fuzzy C-means （SSKFCM） algorithm is proposed to overcome these disadvantages of remote sensing image classification in this paper. The SSKFCM algorithm is achieved by introducing a kernel method and semi-supervised learning technique into the standard fuzzy C-means （FCM） algorithm. A set of Beijing-1 micro-satellite＇s multispectral images are adopted to be classified by several algorithms, such as FCM, kernel FCM （KFCM）, semi-supervised FCM （SSFCM） and SSKFCM. The classification results are estimated by corresponding indexes. The results indicate that the SSKFCM algorithm significantly improves the classification accuracy of remote sensing images compared with the others.
基金supported by National Science and Tech-nology Program of China (Grant No.2006BAK21B03)
文摘The Erlitou site is located at Yanshi City,Henan Province.This site is a large settlement site of Erlitou culture,and it is dated to 3800-3500 a BP.Five kinds of domestic animals,i.e.,dogs,pigs,sheep,goats,and cattle were found from the site.In this paper,two problems have emerged in studies involving the estimation of local isotope levels and the distinction of migrants from locals.Tooth enamel samples from 17 domestic animals individuals were analyzed for strontium isotope ratio(87Sr/86Sr),by the thermal ionization mass spectrometry,including 10 pigs,5 sheep and 2 cattle.The results show that the mean 87Sr/86Sr ratios of 10 pigs enamel samples were 0.712078,Based on the local strontium isotopes ratio range determined by the mean 87Sr/86Sr ratios ±2 of 10 pig enamel samples(0.712256-0.711900),we found that five sheep and one cattle from the Erlitou site fell well outside the local strontium isotopes ratio range and were considered to be non-local.
