A combined method of high performance liquid chromatograph-elecrtrospray-ionization mass spectrometer（HPLC-ESI-MS/MS） coupled with a photodiode array detector（HPLC-DAD） and principal component analysis（PCA） was ...A combined method of high performance liquid chromatograph-elecrtrospray-ionization mass spectrometer（HPLC-ESI-MS/MS） coupled with a photodiode array detector（HPLC-DAD） and principal component analysis（PCA） was applied to the qualitative and quantitative analyses of alkaloids in Cortex Phellodendri（CP） samples, and to the differentiation of two species of CP, Cortex Phellodendri Chinensis（CPC） and Cortex Phellodendri Amurensis（CPA）. Twenty-two peaks appeared in the HPLC-MS base peak chromatogram of CP detected by the HPLC-ESI-MS/MS analysis, and the alkaloids were identified according to the MSn data, the known MS fragmentation rules and the literature data. Five alkaloids including berberine, palmatine, jatrorrhizine, phellodendrine and magnoflorine were simultaneously determinated by the HPLC-DAD. Berberine was the primary component in all CP samples, and the contents of berberine and palmatine were exploited to be two critical parameters for effective discrimination between the two species of CP. The average content of berberine in CPC（58.75 mg/g） was higher than that in CPA（9.16 mg/g）, while the content of palmatine was less, only 0.25 mg/g in CPC and 4.19 mg/g in CPA. With the use of PCA, samples datasets were separated successfully into two different clusters corresponding to the two species, and berberine, pahnatine, phellodendrine and magnoflorine contribute most to the above mentioned calssifying . The proposed method oroved to be a useful tool in the aualitv control of Chinese herbal medicines.展开更多
A detailed landslide-susceptibility map was produced using a data-driven objective bivariate analysis method with datasets developed for a geographic information system （GIS）. Known as one of the most landslide-pron...A detailed landslide-susceptibility map was produced using a data-driven objective bivariate analysis method with datasets developed for a geographic information system （GIS）. Known as one of the most landslide-prone areas in China, the Zhongxian-Shizhu Segment in the Three Gorges Reservoir region of China was selected as a suitable case because of the frequency and distribution of landslides. The site covered an area of 260.93 km^2 with a landslide area of 5.32 km^2. Four data domains were used in this study, including remote sensing products, thematic maps, geological maps, and topographical maps, all with 25 m × 25 m pixels. Statistical relationships for landslide susceptibility were developed using landslide and landslide causative factor databases. All continuous variables were converted to categorical variables according to the percentile divisions of seed cells, and the corresponding class weight values were calculated and summed to create the susceptibility map. According to the map, 3.6% of the study area was identified as high-susceptibility. Extremely low-, very low-, low-, and medium-susceptibility zones covered 19.66%, 31.69%, 27.95%, and 17.1% of the area, respectively. The high- and medium-hazardons zones are along both sides of the Yangtze River, being in agreement with the actual distribution of landslides.展开更多
During hydraulic fracturing operations of low-permeability reservoirs,packers are the key component to ensure the success of multistage fracturing.Packers enable sections of the wellbore to be sealed off and separatel...During hydraulic fracturing operations of low-permeability reservoirs,packers are the key component to ensure the success of multistage fracturing.Packers enable sections of the wellbore to be sealed off and separately fractured by hydraulic pressure,one at a time,while the remainder of the wellbore is not affected.However,reliable sealing properties of the packer rubber are required to meet the high-pressure and high-temperature(HPHT)conditions of reservoirs(such as 70 MPa and 170 ℃).In this study,the structures of the packer rubber with two different materials are optimized numerically by ABAQUS and validated by experiments.The optimization process starts from the packer rubber with a conventional structure,and then,the weakest spots are identified by ABAQUS and improved by slightly varying its structure.This process is iterative,and the final optimized structure of a single rubber barrel with expanding back-up rings is achieved.For the structure of three rubber barrels with metallic protective covers,both HNBR and AFLAS fail under HPHT conditions.For the final optimized structure,the packer rubber made of AFLAS can work better under HPHT than that made of HNBR which ruptures after setting.The results show that the optimized structure of a single rubber barrel with expanding back-up rings and the material AFLAS are a good combination for the packer rubber playing an excellent sealing performance in multistage fracturing in horizontal wells.展开更多
Casing corrosion during CO2 injection or storage results in significant economic loss and increased production risks.Therefore,in this paper,a corroded casing risk assessment model based on analytic hierarchy process ...Casing corrosion during CO2 injection or storage results in significant economic loss and increased production risks.Therefore,in this paper,a corroded casing risk assessment model based on analytic hierarchy process and fuzzy comprehensive evaluation is established to identify potential risks in time.First,the corrosion rate and residual strength characteristics are analyzed through corrosion tests and numerical simulations,respectively,to determine the risk factors that may lead to an accident.Then,an index system for corroded casing risk evaluation is established based on six important factors:temperature,CO2 partial pressure,flow velocity,corrosion radius,corrosion depth and wellhead pressure.Subsequently,the index weights are calculated via the analytic hierarchy process.Finally,the risk level of corroded casing is obtained via the fuzzy comprehensive evaluation.The corroded casing risk assessment model has been verified by a case well,which shows that the model is valuable and feasible.It provides an effective decision-making method for the risk evaluation of corroded casing in CO2 injection well,which is conductive to improve the wellbore operation efficiency.展开更多
For quality control purpose, an approach of fingerprinting and simultaneous quantification of five major bioactive constituents of Rhizoma Coptidis was established via a high-performance liquid chromatograph coupled w...For quality control purpose, an approach of fingerprinting and simultaneous quantification of five major bioactive constituents of Rhizoma Coptidis was established via a high-performance liquid chromatograph coupled with a photodiode array UV detector（HPLC-DAD） and an electrospray ionization mass spectrometer（HPLC-ESI/MS） The compounds were identified on the basis of the comparison of their mass spectra with literature data and those of standard samples and quantified by the HPLC-DAD method. Baseline separation was achieved on an XTerra C18 column（5 μm, 250 mm×4.6 mm i. d.） with linear gradient elution of formate buffer（consisting of 0.5% formic acid, adjusted to pH=4.5 with ammonia） and acetonitrile（consisting of 0.2% formic acid and 0.2% triethylamine）. The me- thod was validated for linearity（r^2〉0.9995）, repeatability（RSD〈3.1%）, intra- and inter-day precision（RSD〈1.8%） with recovery（99.9%-105.1%）, limits of detection（0.15-0.35 μg/mL）, and limits of quantification（0.53-0.82 μg/mL）. The similarities of 32 batches of Rhizoma Coptidis and their classification according to their manufacturers were based on the retention time and peak areas of the characteristic compounds. The five compounds were selected for quality assessment ofRhizoma coptidis via partial least squares analysis（PLS）.展开更多
Taking into account the squat silos with high grain line and large-volume storage characteristics, to ensure that the stored grain secu rity, we compared phosphine RECIRCULATION FUMIGATION OF PHOSPHINE with the conven...Taking into account the squat silos with high grain line and large-volume storage characteristics, to ensure that the stored grain secu rity, we compared phosphine RECIRCULATION FUMIGATION OF PHOSPHINE with the conventional circulation fumigation method and compared with test data which measured by the analysis and research. Squat Silos taken positions on the circulation phosphine fumigation insecticidal methods, not only to achieve the purpose of the pesticide control, and effectively reduce the cost of fumigation, a decrease of gas in the fight against the occu pational hazards, and have achieved good results.展开更多
基金Supported by the National Natural Science Foundation of China(No30725045)the Foundation of Eleventh Five-Year-Plan of China(No2008ZX09202-002)+1 种基金the Shanghai Leading Academic Discipline Project, China(NoB906)the Scientific Foundation of Shanghai City, China(No07DZ19702)
文摘A combined method of high performance liquid chromatograph-elecrtrospray-ionization mass spectrometer（HPLC-ESI-MS/MS） coupled with a photodiode array detector（HPLC-DAD） and principal component analysis（PCA） was applied to the qualitative and quantitative analyses of alkaloids in Cortex Phellodendri（CP） samples, and to the differentiation of two species of CP, Cortex Phellodendri Chinensis（CPC） and Cortex Phellodendri Amurensis（CPA）. Twenty-two peaks appeared in the HPLC-MS base peak chromatogram of CP detected by the HPLC-ESI-MS/MS analysis, and the alkaloids were identified according to the MSn data, the known MS fragmentation rules and the literature data. Five alkaloids including berberine, palmatine, jatrorrhizine, phellodendrine and magnoflorine were simultaneously determinated by the HPLC-DAD. Berberine was the primary component in all CP samples, and the contents of berberine and palmatine were exploited to be two critical parameters for effective discrimination between the two species of CP. The average content of berberine in CPC（58.75 mg/g） was higher than that in CPA（9.16 mg/g）, while the content of palmatine was less, only 0.25 mg/g in CPC and 4.19 mg/g in CPA. With the use of PCA, samples datasets were separated successfully into two different clusters corresponding to the two species, and berberine, pahnatine, phellodendrine and magnoflorine contribute most to the above mentioned calssifying . The proposed method oroved to be a useful tool in the aualitv control of Chinese herbal medicines.
基金supported by the National Natural Science Foundation of China (Nos.40801212 and 49971064)the Foun-dation for China Geological Survey (No.200316000035)+1 种基金the Natural Science Foundation of Jiangsu Higher Education Institutions of China (No.06KJB170063)the Opening Fund of State Key Laboratory of Geohazard Prevention and Geoenvironment Protection of Chendu University of Technology, China (No.GZ2007-11).
文摘A detailed landslide-susceptibility map was produced using a data-driven objective bivariate analysis method with datasets developed for a geographic information system （GIS）. Known as one of the most landslide-prone areas in China, the Zhongxian-Shizhu Segment in the Three Gorges Reservoir region of China was selected as a suitable case because of the frequency and distribution of landslides. The site covered an area of 260.93 km^2 with a landslide area of 5.32 km^2. Four data domains were used in this study, including remote sensing products, thematic maps, geological maps, and topographical maps, all with 25 m × 25 m pixels. Statistical relationships for landslide susceptibility were developed using landslide and landslide causative factor databases. All continuous variables were converted to categorical variables according to the percentile divisions of seed cells, and the corresponding class weight values were calculated and summed to create the susceptibility map. According to the map, 3.6% of the study area was identified as high-susceptibility. Extremely low-, very low-, low-, and medium-susceptibility zones covered 19.66%, 31.69%, 27.95%, and 17.1% of the area, respectively. The high- and medium-hazardons zones are along both sides of the Yangtze River, being in agreement with the actual distribution of landslides.
基金financial support from the Fundamental Research Funds for the Central Universities under Grant nos. 17CX05020 and 17CX06002the Research Funds for Introducing Talent (PhD) of China University of Petroleum under Grant no. YJ20170026+1 种基金the National Science and Technology Major Project under Grant no. 2016ZX05042004the Joint Funds of the National Natural Science Foundation of China under Grant no. U1762104
文摘During hydraulic fracturing operations of low-permeability reservoirs,packers are the key component to ensure the success of multistage fracturing.Packers enable sections of the wellbore to be sealed off and separately fractured by hydraulic pressure,one at a time,while the remainder of the wellbore is not affected.However,reliable sealing properties of the packer rubber are required to meet the high-pressure and high-temperature(HPHT)conditions of reservoirs(such as 70 MPa and 170 ℃).In this study,the structures of the packer rubber with two different materials are optimized numerically by ABAQUS and validated by experiments.The optimization process starts from the packer rubber with a conventional structure,and then,the weakest spots are identified by ABAQUS and improved by slightly varying its structure.This process is iterative,and the final optimized structure of a single rubber barrel with expanding back-up rings is achieved.For the structure of three rubber barrels with metallic protective covers,both HNBR and AFLAS fail under HPHT conditions.For the final optimized structure,the packer rubber made of AFLAS can work better under HPHT than that made of HNBR which ruptures after setting.The results show that the optimized structure of a single rubber barrel with expanding back-up rings and the material AFLAS are a good combination for the packer rubber playing an excellent sealing performance in multistage fracturing in horizontal wells.
基金This work was supported by the National Natural Science Foundation of China(Grant No.2016ZX05042004)the Joint Funds of the National Natural Science Foundation of China(Grant no.U1762104)+3 种基金the Major Scientific and Technological Projects of CNPC(Grant No.ZD2019-184-004)the Fundamental Research Funds for the Central Universities(20CX02306A)the Opening Fund of National Engineering Laboratory of Offshore Geophysical and Exploration EquipmentThe authors also would like to express their sincere gratitude to Dr.Zhang Dalei for his assistance in corrosion tests.
文摘Casing corrosion during CO2 injection or storage results in significant economic loss and increased production risks.Therefore,in this paper,a corroded casing risk assessment model based on analytic hierarchy process and fuzzy comprehensive evaluation is established to identify potential risks in time.First,the corrosion rate and residual strength characteristics are analyzed through corrosion tests and numerical simulations,respectively,to determine the risk factors that may lead to an accident.Then,an index system for corroded casing risk evaluation is established based on six important factors:temperature,CO2 partial pressure,flow velocity,corrosion radius,corrosion depth and wellhead pressure.Subsequently,the index weights are calculated via the analytic hierarchy process.Finally,the risk level of corroded casing is obtained via the fuzzy comprehensive evaluation.The corroded casing risk assessment model has been verified by a case well,which shows that the model is valuable and feasible.It provides an effective decision-making method for the risk evaluation of corroded casing in CO2 injection well,which is conductive to improve the wellbore operation efficiency.
基金Supported by the National Natural Science Foundation of China(No.30725045)Shanghai Leading Academic Discipline Project (No.B906)in part by the Scientific Foundation of Shanghai China(Nos.07DZ19728, 06DZ19717 and 06DZ19005)
文摘For quality control purpose, an approach of fingerprinting and simultaneous quantification of five major bioactive constituents of Rhizoma Coptidis was established via a high-performance liquid chromatograph coupled with a photodiode array UV detector（HPLC-DAD） and an electrospray ionization mass spectrometer（HPLC-ESI/MS） The compounds were identified on the basis of the comparison of their mass spectra with literature data and those of standard samples and quantified by the HPLC-DAD method. Baseline separation was achieved on an XTerra C18 column（5 μm, 250 mm×4.6 mm i. d.） with linear gradient elution of formate buffer（consisting of 0.5% formic acid, adjusted to pH=4.5 with ammonia） and acetonitrile（consisting of 0.2% formic acid and 0.2% triethylamine）. The me- thod was validated for linearity（r^2〉0.9995）, repeatability（RSD〈3.1%）, intra- and inter-day precision（RSD〈1.8%） with recovery（99.9%-105.1%）, limits of detection（0.15-0.35 μg/mL）, and limits of quantification（0.53-0.82 μg/mL）. The similarities of 32 batches of Rhizoma Coptidis and their classification according to their manufacturers were based on the retention time and peak areas of the characteristic compounds. The five compounds were selected for quality assessment ofRhizoma coptidis via partial least squares analysis（PLS）.
文摘Taking into account the squat silos with high grain line and large-volume storage characteristics, to ensure that the stored grain secu rity, we compared phosphine RECIRCULATION FUMIGATION OF PHOSPHINE with the conventional circulation fumigation method and compared with test data which measured by the analysis and research. Squat Silos taken positions on the circulation phosphine fumigation insecticidal methods, not only to achieve the purpose of the pesticide control, and effectively reduce the cost of fumigation, a decrease of gas in the fight against the occu pational hazards, and have achieved good results.
