The chemical compositions of volatile oil from fruiting body of Armillaria luteo-virens in Qinghai Province were firstly analyzed with GC-MS and its relevant compositions were detected by calculating chromatographic p...The chemical compositions of volatile oil from fruiting body of Armillaria luteo-virens in Qinghai Province were firstly analyzed with GC-MS and its relevant compositions were detected by calculating chromatographic peak area with normalized method. 21 peaks were separated and 13 compositions were identified which were mainly unsaturated fatty acids, taking 97.1% of the total volatile oil.展开更多
Aim To investigate the chemical constituents from Potentilla multifida L..Methods Chromatographic technique was employed for the isolation and purification of theconstituents, and the structures were identified by spe...Aim To investigate the chemical constituents from Potentilla multifida L..Methods Chromatographic technique was employed for the isolation and purification of theconstituents, and the structures were identified by spectral evidence. Results Four compounds wereisolated involving ade-nosine (1), apigenin-6-C-arabinopyranosyl-8-C-glucopyranoside (2),apigenin-7-O-β-D-glucuronide (3) and luteolin-7-O-β-D-glucuronide (4). Conclusion The fourcompounds were obtained from the genus Potentilla for the first time.展开更多
The resonator fiber optic gyro （R-FOG） ,which utilizes a resonance frequency change due to the Sagnac effect,is a promising candidate for the next generation inertial rotation sensor. In this study, an open-loop R-F...The resonator fiber optic gyro （R-FOG） ,which utilizes a resonance frequency change due to the Sagnac effect,is a promising candidate for the next generation inertial rotation sensor. In this study, an open-loop R-FOG is set up using phase modulation spectroscopy. First,the demodulation curve is obtained using a lock-in amplifier. From the demodulation signal,a gyro dynamic range of ± 4.2rad/s is obtained. Then,using different phase modulation frequencies,the open-loop gyro output signal is measured when the gyro is rotated clockwise or counterclockwise. The bias drift as a function of time is also measured. The fluctuation of the output over 5s is about 0.02rad/s. The drift can be reduced by taking countermeasures against system noise.展开更多
We develop a system to measure the elemental composition of unprepared samples using laser-induced breakdown spec-troscopy (LIBS) in our laboratory,which can be used for the determination of elements in solids,liquids...We develop a system to measure the elemental composition of unprepared samples using laser-induced breakdown spec-troscopy (LIBS) in our laboratory,which can be used for the determination of elements in solids,liquids and aerosols. A description of the instrumentation,including laser,sample chamber and detection,is followed by a brief discussion. The time-resolved LIBS of aluminum at atmospheric pressure is presented. At the end,the possibilities and later uses of this technique are briefly discussed.展开更多
A new method to detect multiple outliers in multivariate data is proposed. It is a combination of minimum subsets, resampling and self-organizing map (SOM) algorithm introduced by Kohonen,which provides a robust way w...A new method to detect multiple outliers in multivariate data is proposed. It is a combination of minimum subsets, resampling and self-organizing map (SOM) algorithm introduced by Kohonen,which provides a robust way with neural network. In this method, the number and organization of the neurons are selected by the characteristics of the spectra, e.g., the spectra data are often changed linearly with the concentration of the components and are often measured repeatedly, etc. So the spatial distribution of the neurons can be arranged by this characteristic. With this method, all the outliers in the spectra can be detected, which cannot be solved by the traditional method, and the speed of computation is higher than that of the traditional neural network method. The results of the simulation and the experiment show that this method is simple, effective, intuitionistic and all the outliers in the spectra can be detected in a short time. It is useful when associated with the regression model in the near infra-red research.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
Disaccharides are a very important group of carbohydrates, being main components of many daily food products. The heating of these biomolecule causes the formation of caramel, an extremely complex material. The domina...Disaccharides are a very important group of carbohydrates, being main components of many daily food products. The heating of these biomolecule causes the formation of caramel, an extremely complex material. The dominant fraction of non-volatile compounds, responsible for both color and flavor of food products, has been studied on a few occasions. Herein, the composition of caramels obtained by heating of sucrose, lactose and maltose were studied using combined mass spectrometry techniques. High resolution electrospray mass spectrometry was applied followed by targeted multi-stage LC-tandem mass spectrometry （ESI-MSn） and MALDI-MS. Novel graphical interpretation strategies such as van Krevelen and Kendrick mass analysis have been applied to study the composition of caramels. Products of caramel include oligomerization, depolymerization, hydration and dehydration products. Oligomers with up to eight carbohydrate units and dehydrated oligomers losing up to eight water molecules have been identified.展开更多
Trans-sobrerol （Sob） and 8-p-menthen-1,2-diol （Limo-diol） are the primary products in the atmospheric oxidation of α-pinene and limonene, respectively. Because of their low volatility, they associate more likely ...Trans-sobrerol （Sob） and 8-p-menthen-1,2-diol （Limo-diol） are the primary products in the atmospheric oxidation of α-pinene and limonene, respectively. Because of their low volatility, they associate more likely to the liquid particles in the atmosphere, where they are subject to the aqueous phase oxidation by the atmospheric oxidants. In this work, through experimental and theoretical study, we first provide the rate constants of Sob and Limo-diol reacting with hydroxyl radical （.OH） in aqueous solution at room temperature of 3044-3 K and 1 atm pressure, which are （3.05±0.5）×10 9 and （4.57±0.2）×10 9 L/（mol.s）, respectively. Quantum chemistry calculations have also been employed to demonstrate the solvent effect on the rate constants in aqueous phase and the calculated results agree well with the measurements. Some reaction products have been identified based on liquid chromatography combined with mass spectroscopy and theoretical calculations.展开更多
A three-tip array is used in the HL-2A tokamak to investigate the spectral characteristics of electrostatic turbulence inside the last closed flux surface （LCFS） about 5 cm. Two-point correlation techniques are used...A three-tip array is used in the HL-2A tokamak to investigate the spectral characteristics of electrostatic turbulence inside the last closed flux surface （LCFS） about 5 cm. Two-point correlation techniques are used to analysis the turbulence structure. It is found that the drift wave turbulence mainly is composed of low-frequency and long wavelength wave packets. The poloidal propagation is mainly in electron-diamagnetic direction, sometimes it propagates in ion-diamagnetic direction, which is influenced by Doppler-frequency shift. The radial propagation velocity is outward and the sizeable fraction of the poloidal velocity, implying that the radial mode plays an important role in the cross field transport.展开更多
Silver nanoparticles （Ag-NPs） were prepared using an electrochemical technique. The optical properties were measured by absorption spectroscopy. The dimension of the prepared nanoparticles as estimated by the Atomic...Silver nanoparticles （Ag-NPs） were prepared using an electrochemical technique. The optical properties were measured by absorption spectroscopy. The dimension of the prepared nanoparticles as estimated by the Atomic Force Microscope （AFM）, was 91.57 nm. This reaserch effort proposes a mechanism for reducing the size of silver nanoparticles by adding the hydrogen peroxide （H202）, and protecting the silver nanoparticle to inhibit agglomeration by adding PVP polymer.展开更多
The miRNA expression profile was initially established to investigate its corresponding function in human uveal melanoma. The miRNA expression profile in human uveal melanoma was analyzed by a micro chip technique.The...The miRNA expression profile was initially established to investigate its corresponding function in human uveal melanoma. The miRNA expression profile in human uveal melanoma was analyzed by a micro chip technique.The hsa-miRNA expression between four uveal melanomas and four normal uveal tissues was compared.Based on the bioinformatic approach,chip data was analyzed to select out differentially expressed candidate hsa-miRNAs.Real-time quantitative PCR(RT-PCR) was used to confirm the candidate hsa-miRNAs expression in all samples.The results of miRNA microarray chips that matched with RT-PCR were considered as the miRNA expression which was significantly different between normal tissue and uveal melanomas.In four uveal melanomas,expressions of miRNA-20a,miRNA-106a,miRNA-17,miRNA-21,and miRNA-34a were significantly up-regulated,while miRNA-145 and miRNA-204 expression were significantly down-regulated.We used miRNA microarray analysis as a fast,efficient technology to study biological information.The differentially expressed miRNAs may be involved in uveal melanoma pathogenesis,and may help promote the diagnosis and treatment for uveal melanoma.展开更多
Fingerprints have been used as an indispensable tool for personal identification in forensic investigations since the late 19 th century. At present, fingerprinting technology has moved away from its forensic roots an...Fingerprints have been used as an indispensable tool for personal identification in forensic investigations since the late 19 th century. At present, fingerprinting technology has moved away from its forensic roots and is incorporating a broader scientific range, e.g., material science, spectroscopy and spectral analysis, and even in vitro diagnosis. After a brief introduction to latent fingerprints, this mini-review presents the pioneering progresses of fingerprinting technologies including(i) material and electrochemical techniques, and(ii) spectral and spectroscopy imaging techniques and immunological techniques capable of both the visualization of a fingerprint and the detection of chemicals present in it. Finally, perspectives on this rapidly developing field are discussed.展开更多
基金supported by the National Key Research and Development Program of China(2017YFA0402800)the National Natural Science Foundation of China(11475176,U1632263,21533007,and 11621063)~~
基金the National Natural Science Foundation of China (30460083)the Key Science and Technology Project of Chinese Ministry of Education (205164)~~
文摘The chemical compositions of volatile oil from fruiting body of Armillaria luteo-virens in Qinghai Province were firstly analyzed with GC-MS and its relevant compositions were detected by calculating chromatographic peak area with normalized method. 21 peaks were separated and 13 compositions were identified which were mainly unsaturated fatty acids, taking 97.1% of the total volatile oil.
文摘Aim To investigate the chemical constituents from Potentilla multifida L..Methods Chromatographic technique was employed for the isolation and purification of theconstituents, and the structures were identified by spectral evidence. Results Four compounds wereisolated involving ade-nosine (1), apigenin-6-C-arabinopyranosyl-8-C-glucopyranoside (2),apigenin-7-O-β-D-glucuronide (3) and luteolin-7-O-β-D-glucuronide (4). Conclusion The fourcompounds were obtained from the genus Potentilla for the first time.
文摘The resonator fiber optic gyro （R-FOG） ,which utilizes a resonance frequency change due to the Sagnac effect,is a promising candidate for the next generation inertial rotation sensor. In this study, an open-loop R-FOG is set up using phase modulation spectroscopy. First,the demodulation curve is obtained using a lock-in amplifier. From the demodulation signal,a gyro dynamic range of ± 4.2rad/s is obtained. Then,using different phase modulation frequencies,the open-loop gyro output signal is measured when the gyro is rotated clockwise or counterclockwise. The bias drift as a function of time is also measured. The fluctuation of the output over 5s is about 0.02rad/s. The drift can be reduced by taking countermeasures against system noise.
文摘We develop a system to measure the elemental composition of unprepared samples using laser-induced breakdown spec-troscopy (LIBS) in our laboratory,which can be used for the determination of elements in solids,liquids and aerosols. A description of the instrumentation,including laser,sample chamber and detection,is followed by a brief discussion. The time-resolved LIBS of aluminum at atmospheric pressure is presented. At the end,the possibilities and later uses of this technique are briefly discussed.
文摘A new method to detect multiple outliers in multivariate data is proposed. It is a combination of minimum subsets, resampling and self-organizing map (SOM) algorithm introduced by Kohonen,which provides a robust way with neural network. In this method, the number and organization of the neurons are selected by the characteristics of the spectra, e.g., the spectra data are often changed linearly with the concentration of the components and are often measured repeatedly, etc. So the spatial distribution of the neurons can be arranged by this characteristic. With this method, all the outliers in the spectra can be detected, which cannot be solved by the traditional method, and the speed of computation is higher than that of the traditional neural network method. The results of the simulation and the experiment show that this method is simple, effective, intuitionistic and all the outliers in the spectra can be detected in a short time. It is useful when associated with the regression model in the near infra-red research.
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.
文摘Disaccharides are a very important group of carbohydrates, being main components of many daily food products. The heating of these biomolecule causes the formation of caramel, an extremely complex material. The dominant fraction of non-volatile compounds, responsible for both color and flavor of food products, has been studied on a few occasions. Herein, the composition of caramels obtained by heating of sucrose, lactose and maltose were studied using combined mass spectrometry techniques. High resolution electrospray mass spectrometry was applied followed by targeted multi-stage LC-tandem mass spectrometry （ESI-MSn） and MALDI-MS. Novel graphical interpretation strategies such as van Krevelen and Kendrick mass analysis have been applied to study the composition of caramels. Products of caramel include oligomerization, depolymerization, hydration and dehydration products. Oligomers with up to eight carbohydrate units and dehydrated oligomers losing up to eight water molecules have been identified.
基金This work was supported by the National Natural Science Foundation of China （No.21177041 and No.21107026）, the Fundamental Research Funds for the Central Universities （No.2013ZZ0073）, and the Scientific Research Foundation for Returned Overseas Chinese Scholars, State Education Ministry.
文摘Trans-sobrerol （Sob） and 8-p-menthen-1,2-diol （Limo-diol） are the primary products in the atmospheric oxidation of α-pinene and limonene, respectively. Because of their low volatility, they associate more likely to the liquid particles in the atmosphere, where they are subject to the aqueous phase oxidation by the atmospheric oxidants. In this work, through experimental and theoretical study, we first provide the rate constants of Sob and Limo-diol reacting with hydroxyl radical （.OH） in aqueous solution at room temperature of 3044-3 K and 1 atm pressure, which are （3.05±0.5）×10 9 and （4.57±0.2）×10 9 L/（mol.s）, respectively. Quantum chemistry calculations have also been employed to demonstrate the solvent effect on the rate constants in aqueous phase and the calculated results agree well with the measurements. Some reaction products have been identified based on liquid chromatography combined with mass spectroscopy and theoretical calculations.
基金Supported by National Natural Science Foundation of China （10675041） First authors would give thanks to the HL-2A team for steady state discharges.
文摘A three-tip array is used in the HL-2A tokamak to investigate the spectral characteristics of electrostatic turbulence inside the last closed flux surface （LCFS） about 5 cm. Two-point correlation techniques are used to analysis the turbulence structure. It is found that the drift wave turbulence mainly is composed of low-frequency and long wavelength wave packets. The poloidal propagation is mainly in electron-diamagnetic direction, sometimes it propagates in ion-diamagnetic direction, which is influenced by Doppler-frequency shift. The radial propagation velocity is outward and the sizeable fraction of the poloidal velocity, implying that the radial mode plays an important role in the cross field transport.
文摘Silver nanoparticles （Ag-NPs） were prepared using an electrochemical technique. The optical properties were measured by absorption spectroscopy. The dimension of the prepared nanoparticles as estimated by the Atomic Force Microscope （AFM）, was 91.57 nm. This reaserch effort proposes a mechanism for reducing the size of silver nanoparticles by adding the hydrogen peroxide （H202）, and protecting the silver nanoparticle to inhibit agglomeration by adding PVP polymer.
基金supported by the Beijing Municipal Natural Science Foundation(Grant Nos.7092021 and 7072019)the Beijing Science and Technology Support(Grant No.Z08050703080882)the National Natural Science Foundation of China(Grant No.30571988)
文摘The miRNA expression profile was initially established to investigate its corresponding function in human uveal melanoma. The miRNA expression profile in human uveal melanoma was analyzed by a micro chip technique.The hsa-miRNA expression between four uveal melanomas and four normal uveal tissues was compared.Based on the bioinformatic approach,chip data was analyzed to select out differentially expressed candidate hsa-miRNAs.Real-time quantitative PCR(RT-PCR) was used to confirm the candidate hsa-miRNAs expression in all samples.The results of miRNA microarray chips that matched with RT-PCR were considered as the miRNA expression which was significantly different between normal tissue and uveal melanomas.In four uveal melanomas,expressions of miRNA-20a,miRNA-106a,miRNA-17,miRNA-21,and miRNA-34a were significantly up-regulated,while miRNA-145 and miRNA-204 expression were significantly down-regulated.We used miRNA microarray analysis as a fast,efficient technology to study biological information.The differentially expressed miRNAs may be involved in uveal melanoma pathogenesis,and may help promote the diagnosis and treatment for uveal melanoma.
基金supported by the National Natural Science Foundation of China(21222504,21335001)the Program for New Century Excellent Talents in University+2 种基金the Scholarship Award for Excellent Doctoral Student granted by the Ministry of Educationthe Nature Science Foundation of Zhejiang Province(R14B050003)the Fundamental Research Funds for Central Universities(2014XZZX003-04)
文摘Fingerprints have been used as an indispensable tool for personal identification in forensic investigations since the late 19 th century. At present, fingerprinting technology has moved away from its forensic roots and is incorporating a broader scientific range, e.g., material science, spectroscopy and spectral analysis, and even in vitro diagnosis. After a brief introduction to latent fingerprints, this mini-review presents the pioneering progresses of fingerprinting technologies including(i) material and electrochemical techniques, and(ii) spectral and spectroscopy imaging techniques and immunological techniques capable of both the visualization of a fingerprint and the detection of chemicals present in it. Finally, perspectives on this rapidly developing field are discussed.
