China is lack of bromine and potassium seriously.Oilfield brines is the headline goal of bromine and potassium resources exploration.Applicants grab 24oilfield brines samples from various wells of Ordovician
GB/T 13245-91 1 Theme and Scope This standard specifies the method abstract, reagents, apparatus, specimen, analyzing procedure, result calculation and permissible tolerance used for determination of the total carbon ...GB/T 13245-91 1 Theme and Scope This standard specifies the method abstract, reagents, apparatus, specimen, analyzing procedure, result calculation and permissible tolerance used for determination of the total carbon with combustion gravimetric method.展开更多
Fingerprints of two varieties of rice and their mixtures were investigated by a nonlinear chemical reaction system consisting of rice components,sodium bromate,manganese sulfate,sulfuric acid and acetone.The variety o...Fingerprints of two varieties of rice and their mixtures were investigated by a nonlinear chemical reaction system consisting of rice components,sodium bromate,manganese sulfate,sulfuric acid and acetone.The variety of rice was identified by the visual characteristic of fingerprint and system similarity pattern recognition,and the content of each variety of rice in the mixture was determined by the quantitative information of fingerprint.The results show that nonlinear chemical analysis may be used to exactly identify the variety of pure rice and to accurately determine the content of each variety of rice in the mixture,indicating the method is simple and convenient.展开更多
This standard specifies the method summary, reagents, apparatus, sampling, procedure, test results calculation and permissible tolerance of the determination of magnesium oxide by CyDTA volumetric method.
Present study is carried out in the bone samples collected from Roopkund Lake in district Chamoli Garhwal, Uttarakhand which is located at 5,029 meters from main sea level in between Nanda Ghunghti and Trishuli peak. ...Present study is carried out in the bone samples collected from Roopkund Lake in district Chamoli Garhwal, Uttarakhand which is located at 5,029 meters from main sea level in between Nanda Ghunghti and Trishuli peak. This historical site belongs to 9th century A.D. All the samples selected for the study were dried in room temperature as well as hot air oven at 32 ~C. Cleaning, pretreatment and digestion process of faunal remains was followed through established scientific methods. Chemical analysis i.e. concentration of different elements such as calcium, strontium, barium, magnesium and zinc as well as isotopic ratios of Carbon and Nitrogen was estimated with the help of ICP （inductively coupled plasma spectroscopy） and AAS （atomic absorption spectrophotometer）. The results obtained from the chemical analysis are significant. On the basis of concentration of different elements and ratios of Nitrogen and Carbon isotopes, the dietary habits of the peoples buried in the Roopkund Lake are identified, which is different from sample to sample person to person. Besides this, the results are also significantly helpful for knowing the preservation status of faunal remains in Roopkund Lake. Finally this study also indicated the potentiality of chemical analysis for reconstructing the palaeodiet behaviour and preservation status of bone remains.展开更多
The integrated steelmaking cycle based on the blast furnace-basic oxygen furnace（BOF）route plays an important role in the production of plain and ultra-low carbon steel,especially for deep drawing operations.BOF ste...The integrated steelmaking cycle based on the blast furnace-basic oxygen furnace（BOF）route plays an important role in the production of plain and ultra-low carbon steel,especially for deep drawing operations.BOF steelmaking is based on the conversion of cast iron in steel by impinging oxygen on the metal bath at supersonic speed.In order to avoid the addition of detrimental chemical elements owing to the introduction of uncontrolled scrap and in order to decrease environmental impact caused by the intensive use of coke for the production of cast iron,HBI（hot briquetted iron）can be used as a source of metal and a fraction of cast iron.Forty industrial experimental tests were performed to evaluate the viability of the use of HBI in BOF.The experimental campaign was supported by a thermal prediction model and realized through the estimation of the oxidation enthalpy.Furthermore,the process was thermodynamically analyzed based on oxygen potentials using the off-gas composition and the bath temperature evolution during the conversion as reference data.展开更多
A problem in chemical analysis in connection with measurements of a substance normally occurring in a sample, or identification of a substance which should not exist in a sample, is insufficient selectivity. In this a...A problem in chemical analysis in connection with measurements of a substance normally occurring in a sample, or identification of a substance which should not exist in a sample, is insufficient selectivity. In this article, we analyze this problem and propose remedies. We use a real doping case to illustrate how chemical noise causes a serious selectivity problem, probably causing a false positive outcome.展开更多
The application of gas chromatography technology in the chemical industry is more prominent, which can realize the detection of gas in an efficient and convenient way, provide a more reasonable choice for the producti...The application of gas chromatography technology in the chemical industry is more prominent, which can realize the detection of gas in an efficient and convenient way, provide a more reasonable choice for the production of chemical enterprises, improve the development quality of the entire industry, and also provide support for related technologies. Relevant scientific researchers should continuously and deeply explore the advantages of chromatographic analysis technology, intensify the research on chromatographic analysis technology, so as to maximize the application level of chromatographic analysis technology in China and promote the development of chemical analysis field in China.展开更多
The main proteases(M^(pro)s)are hydrolases playing essential roles in the replication ofβ-coronaviruses including SARS-CoV-2.Herein,a highly efficient strategy was developed for discovering the M^(pro)inactivators fr...The main proteases(M^(pro)s)are hydrolases playing essential roles in the replication ofβ-coronaviruses including SARS-CoV-2.Herein,a highly efficient strategy was developed for discovering the M^(pro)inactivators from crude plant extract integrating target-based biochemical assay and chemoproteomic approaches.Firstly,Pu-erh tea was found to potently suppress SARS-CoV-2 M^(pro)in a time-dependent manner.Next,global chemical analysis coupling with peptide-modification profiling were used to identify the cysteine-modified constituents in Pu-erh tea.The results suggested that seven constituents in Pu-erh tea could modify SARSCoV-2 M^(pro),which turned out that epigallocatechin,gallocatechin and gallic acid were the most efficacious M^(pro)inactivators.Further investigations demonstrated that epigallocatechin and gallocatechin could inactivate S ARS-CoV-2 M^(pro)via blocking the formation of the homodimers.Collectively,this work proposed a novel and practical strategy for highly efficient discovery of time-dependent inhibitors of SARS-CoV-2 M^(pro)from plant extracts,while 3 constituents in Pu-erh tea have emerged as robust SARS-CoV-2 M^(pro)inactivators.展开更多
This study explored the thermo-chemical properties of industrial hemp hurd with different provenances,maturity stages,and retting protocols.The findings were then compared to hemp hurd used in the fabrication of citri...This study explored the thermo-chemical properties of industrial hemp hurd with different provenances,maturity stages,and retting protocols.The findings were then compared to hemp hurd used in the fabrication of citric acid-bonded ultra-low-density hemp hurd particleboard.Pyrolysis-gas chromatography-mass spectrometry(Py-GC/MS),Fourier-transform infrared spectroscopy(FTIR),and thermogravimetric analysis(TGA)were employed to document the variability of the hurd and comprehend the potential impact on biobased composite applications.The choice of cultivar,maturity stage,and processing modality significantly influenced the chemical composition,presence of functional groups,and thermal stability of the hurd.Py-GC/MS revealed substantial variations in the lignin-to-carbohydrate(L/C)ratio,along with the absence of fatty acids in certain cultivars.While FTIR signals confirmed consistent functional groups,differences in peak intensities were indicative of carbohydrate variations associated with maturity and retting duration,impacting the availability of hydroxyl groups for,i.e.,interparticle bonding in citric acid-based bio-composites.Furthermore,it was observed that shorter retting durations initially enhanced the thermal resistance,but prolonged retting led to accelerated degradation,significantly reducing the hurd’s residual mass.The findings indicated notable differences among the samples,emphasizing the importance of investigating variables such as provenance/cultivar,maturity,and processing modality.This assessment is essential to ensure effective agronomic practices that align the raw material characteristics with the specific requirements of intended applications,such as the fabrication of biobased hemp hurd composites.展开更多
Ozonolysis products of four lepidopteral pheromone were identified by methane CI-MS.The spectra obtained were notably simpler than those of EI-MS,the peak of molecular ion was normally close to the base peak,and the c...Ozonolysis products of four lepidopteral pheromone were identified by methane CI-MS.The spectra obtained were notably simpler than those of EI-MS,the peak of molecular ion was normally close to the base peak,and the characteristic fragment ions were high in m/z,thereby the interpretation was facilitated.展开更多
This work aims to elucidate the chemical constituents of Kai-Xin-San（KXS） and its metabolites in rat plasma.KXS extracts were separated on an Agilent HPLC SB-C 18 column,analyzed by ion-trap tandem mass spectrometry...This work aims to elucidate the chemical constituents of Kai-Xin-San（KXS） and its metabolites in rat plasma.KXS extracts were separated on an Agilent HPLC SB-C 18 column,analyzed by ion-trap tandem mass spectrometry and high-accuracy qTOF mass spectrometry in negative ion mode.A total of 39 compounds,including 11 ginsenosides,14 Polygala saponins,5 sucrose esters,8 oligosaccharide esters and 1 xanthone were characterized from KXS.Fifteen of them were confirmed by reference standards.No constituents were detected from Poria or Acori Tatarinowii Rhizoma.After oral administration of KXS（7 g/kg）,10 ginsenosides and 18 Polygala compounds were detected in rat plasma.This study indicates that ginseng saponins,Polygala saponins and saccharide esters could be the major effective components of KXS prescription.展开更多
An ultra high performance liquid chromatography coupled with hybrid quadrupole-orbitrap mass spectrometry （UHPLC-quadrupole-orbitrap MS） method was developed to systematically analyze chemical constituents of Scutel...An ultra high performance liquid chromatography coupled with hybrid quadrupole-orbitrap mass spectrometry （UHPLC-quadrupole-orbitrap MS） method was developed to systematically analyze chemical constituents of Scutellaria barbata D. Don. The 70% methanol extract was separated on an Agilent Eclipse Plus Cl8 column （1.8μm, 150 mm×2.1 mm）, and eluted with a gradient of methanol-acetonitrile-water containing 0.1% formic acid at a flow rate of 0.25 mL/min. Constituents were identified by HRMS in the negative ion mode using both full scan and two-stage threshold-triggered mass modes. A total of 56 compounds, including 20 free flavonoids, 20 flavonoid O-glycosides, 2 flavonoid C-glycosides, 4 phenylethanoid glycosides, and 10 phenolic compounds were identified by analyzing their high resolution mass spectral data. Among them, 8 flavonoids and 2 phenylethanoid glycosides were unambiguously identified by comparing with reference standards. This study demonstrates that hybrid quadrupole-orbitrap mass spectrometry is a powerful tool in structural identification of unknown compounds in comolicated herbal extracts.展开更多
The project consists in the implementation of a biocomposite based on tannin resin and natural rubber matrices with the bast fibres of <i>Triumfetta cordifolia </i>A.Rich.“<i>Okong</i>” from ...The project consists in the implementation of a biocomposite based on tannin resin and natural rubber matrices with the bast fibres of <i>Triumfetta cordifolia </i>A.Rich.“<i>Okong</i>” from the equatorial region of Cameroon as reinforcement. A study of this still little known fibre is necessary. This paper evaluates the physico-chemical and mechanical characteristics of the fibers. The fibers are extracted by us. A series of experiments is conducted for this purpose: morphological observation with a scanning electron microscope (SEM);density evaluation with a helium pycnometer;absorption rate evaluation according to the protocol available in the literature, Fourier Transform Infrared Spectrometry (FT-IR), chemical composition evaluation according to ASTM 1972 and ASTM 1977 standards, thermogravimetric analysis (TGA) and tensile tests on fiber bundles according to NF T25-501-3. The results show that the fiber is made up of several elementary fibers with oval cross-sections. A density of 1.477g/cm<sup>3</sup> close to that of hemp. These fibers have a water absorption rate of 342.5%, which correlates with the presence of free hydroxyl functional groups obtained from the spectrometry study (FT-IR). Chemical analysis reveals that the fiber is made up of celluloses (44.4%), hemicelluloses (30.8%), lignins (18.9%), pectins (3.3%), waxes (0.5%) and minerals (2.1%). In addition, we learn that the fibers studied dehydrate at 11.49%, showinga notable thermal stability around 235°C with a peak thermal decomposition of cellulose located at 420°C. In terms of mechanical behaviour, the results reveal that the fibers offer a Young’s modulus in traction of 12.4 ± 6.9 GPa, a tensile strength of 526 ± 128 MPa and an elongation at break of 2.25%. The information thus obtained makes it possible to place these fibers in the same fiber group as flax and jute. They could therefore be used for the same types of applications. They also inform us that these fibers can withstand the temperatures of composite shaping by thermocompression.展开更多
For the handling, treatment and utilization of fly ash from biomass combustion its chemical composition and physical properties are important. In this study eight filter fly ashes from different grate-fired biomass co...For the handling, treatment and utilization of fly ash from biomass combustion its chemical composition and physical properties are important. In this study eight filter fly ashes from different grate-fired biomass combustion plants were investigated. In fly ash from straw combustion high concentrations of（K） were found, whereas in the fly ash from wood combustion the concentrations of Ca and Mg were higher. The average concentration of PO3-4was similar in both types of fly ashes. In all wood fly ashes some measured heavy metal concentrations were above the limits for utilization. The straw fly ashes were much less contaminated and can be utilized. For wood fly ash most parameters showed little variation, except from one fly ash where the dust pre-separator is in poor condition. The average values were： mass median diameter 4.3 ± 0.8 μm, spread of particle size distribution19 ± 11, particle density 2620 ± 80 kg/m^3 and angle of repose 50°± 1°. The density of the straw fly ashes is lower（2260 ± 80 kg/m^3） and the spread of the size distribution is higher（72 ± 24）.For one straw combustion fly ash the values of the mass median diameter and the angle of repose were similar to the values of wood combustion fly ash, for the other straw fly ash the values differed considerably. While the particle size of this fly ash was much smaller,surprisingly the angle of repose was also lower. This can be attributed to the formation of small agglomerates in this fly ash, which were not disintegrated without a certain stress.展开更多
SBS(styrene-butadiene-styrene block copolymer)has been widely used in pavement industry as an asphalt modifier.Nanomaterials can further enhance the performance of SBS modified asphalt.However,rare studies investigate...SBS(styrene-butadiene-styrene block copolymer)has been widely used in pavement industry as an asphalt modifier.Nanomaterials can further enhance the performance of SBS modified asphalt.However,rare studies investigate the feasibility of using graphene as a performance enhancer of SBS modified asphalt.To fill this gap,comprehensive experimental tests including chemical and mechanical test were carried out on SBS-graphene modified asphalt and SEBS(styrene-ethylene-butylene-styrene block copolymer,which is a hydrogenated polymer of SBS)modified asphalt.Graphene with different dimensions and contents was taken into consideration in this study.Based on the experimental work,it can be concluded that graphene improves the mid-temperature performance of SBS modified asphalt.Compared with two-dimensional graphene,three-dimensional graphene has a greater advantage and the enhancement effect increases with the increase of its dosage.In addition,the cross-linked structure of SBS-graphene composite improves the distribution of SBS in asphalt,which improves the overall performance of SBS modified asphalt.展开更多
To our knowledge,precise data concerning the pollution in terms of qualitative and quantitative fluctuations in discharge water from the laundry sector have seldom been reported.This study investigated the chemical co...To our knowledge,precise data concerning the pollution in terms of qualitative and quantitative fluctuations in discharge water from the laundry sector have seldom been reported.This study investigated the chemical composition of the discharge water from a laundry industry.Over 160 chemical substances and 15 standard water parameters were monitored.The results showed that the discharge water presented both inorganic and organic polycontamination with a high degree of qualitative and quantitative variability.However,of all monitored substances,only five metals(Al,Cu,Fe,Sr,and Zn),five minerals(P,Ca,K,Na,and S),and alkylphenols were systematically present and quantifiable.For a daily average water flow of 129 m^(3),the released metal flux was 356 g/d.Substances,such as trichloromethane,brominated diphenyl ether(BDE)47,and fluorides,were occasionally found and quantified.Other substances,such as chlorophenols,organo-tins,and pesticides were never identified.All the samples had quantifiable levels in the chemical oxygen demand(COD),biological oxygen demand(BOD),and hydrocarbons.Only the concentrations of Zn(8.3 g/d),Cu(21.4 g/d),and BOD(57.4 g/d)were close to or above the regulatory values:74.0 g/d for Zn,9.0 g/d for Cu,and 57.0 kg/d for BOD.The data obtained from this study are useful to the choice of additional treatments for the reduction of pollutant fluxes.展开更多
基金supported by Geological survey project (Project Number: 12120113078500)
文摘China is lack of bromine and potassium seriously.Oilfield brines is the headline goal of bromine and potassium resources exploration.Applicants grab 24oilfield brines samples from various wells of Ordovician
文摘GB/T 13245-91 1 Theme and Scope This standard specifies the method abstract, reagents, apparatus, specimen, analyzing procedure, result calculation and permissible tolerance used for determination of the total carbon with combustion gravimetric method.
基金Project(61533021) supported by the National Natural Science Foundation of China
文摘Fingerprints of two varieties of rice and their mixtures were investigated by a nonlinear chemical reaction system consisting of rice components,sodium bromate,manganese sulfate,sulfuric acid and acetone.The variety of rice was identified by the visual characteristic of fingerprint and system similarity pattern recognition,and the content of each variety of rice in the mixture was determined by the quantitative information of fingerprint.The results show that nonlinear chemical analysis may be used to exactly identify the variety of pure rice and to accurately determine the content of each variety of rice in the mixture,indicating the method is simple and convenient.
文摘This standard specifies the method summary, reagents, apparatus, sampling, procedure, test results calculation and permissible tolerance of the determination of magnesium oxide by CyDTA volumetric method.
文摘Present study is carried out in the bone samples collected from Roopkund Lake in district Chamoli Garhwal, Uttarakhand which is located at 5,029 meters from main sea level in between Nanda Ghunghti and Trishuli peak. This historical site belongs to 9th century A.D. All the samples selected for the study were dried in room temperature as well as hot air oven at 32 ~C. Cleaning, pretreatment and digestion process of faunal remains was followed through established scientific methods. Chemical analysis i.e. concentration of different elements such as calcium, strontium, barium, magnesium and zinc as well as isotopic ratios of Carbon and Nitrogen was estimated with the help of ICP （inductively coupled plasma spectroscopy） and AAS （atomic absorption spectrophotometer）. The results obtained from the chemical analysis are significant. On the basis of concentration of different elements and ratios of Nitrogen and Carbon isotopes, the dietary habits of the peoples buried in the Roopkund Lake are identified, which is different from sample to sample person to person. Besides this, the results are also significantly helpful for knowing the preservation status of faunal remains in Roopkund Lake. Finally this study also indicated the potentiality of chemical analysis for reconstructing the palaeodiet behaviour and preservation status of bone remains.
文摘The integrated steelmaking cycle based on the blast furnace-basic oxygen furnace（BOF）route plays an important role in the production of plain and ultra-low carbon steel,especially for deep drawing operations.BOF steelmaking is based on the conversion of cast iron in steel by impinging oxygen on the metal bath at supersonic speed.In order to avoid the addition of detrimental chemical elements owing to the introduction of uncontrolled scrap and in order to decrease environmental impact caused by the intensive use of coke for the production of cast iron,HBI（hot briquetted iron）can be used as a source of metal and a fraction of cast iron.Forty industrial experimental tests were performed to evaluate the viability of the use of HBI in BOF.The experimental campaign was supported by a thermal prediction model and realized through the estimation of the oxidation enthalpy.Furthermore,the process was thermodynamically analyzed based on oxygen potentials using the off-gas composition and the bath temperature evolution during the conversion as reference data.
文摘A problem in chemical analysis in connection with measurements of a substance normally occurring in a sample, or identification of a substance which should not exist in a sample, is insufficient selectivity. In this article, we analyze this problem and propose remedies. We use a real doping case to illustrate how chemical noise causes a serious selectivity problem, probably causing a false positive outcome.
文摘The application of gas chromatography technology in the chemical industry is more prominent, which can realize the detection of gas in an efficient and convenient way, provide a more reasonable choice for the production of chemical enterprises, improve the development quality of the entire industry, and also provide support for related technologies. Relevant scientific researchers should continuously and deeply explore the advantages of chromatographic analysis technology, intensify the research on chromatographic analysis technology, so as to maximize the application level of chromatographic analysis technology in China and promote the development of chemical analysis field in China.
基金the supporting of Shanghai Science and Technology Innovation Action Plans(21S21900600,20S21901500,20S21900900)supported by Shanghai Science and Technology Committee+5 种基金the NSF of China(82273897,81922070,81973286,82104281,82173798)the Innovation Team and Talents Cultivation Program of National Administration of Traditional Chinese Medicine(ZYYCXTDD-202004)the Three-year Action Plan for Shanghai TCM Development and Inheritance Program(ZY(2021-2023)-0401)Shanghai Municipal Health Commission’s TCM Research Project(2022CX005)Shanghai Municipal Science and Technology Major Project(ZD2021CY001)Excellent Doctoral Student Cultivation Projects in Key Fields(GJ2022012)。
文摘The main proteases(M^(pro)s)are hydrolases playing essential roles in the replication ofβ-coronaviruses including SARS-CoV-2.Herein,a highly efficient strategy was developed for discovering the M^(pro)inactivators from crude plant extract integrating target-based biochemical assay and chemoproteomic approaches.Firstly,Pu-erh tea was found to potently suppress SARS-CoV-2 M^(pro)in a time-dependent manner.Next,global chemical analysis coupling with peptide-modification profiling were used to identify the cysteine-modified constituents in Pu-erh tea.The results suggested that seven constituents in Pu-erh tea could modify SARSCoV-2 M^(pro),which turned out that epigallocatechin,gallocatechin and gallic acid were the most efficacious M^(pro)inactivators.Further investigations demonstrated that epigallocatechin and gallocatechin could inactivate S ARS-CoV-2 M^(pro)via blocking the formation of the homodimers.Collectively,this work proposed a novel and practical strategy for highly efficient discovery of time-dependent inhibitors of SARS-CoV-2 M^(pro)from plant extracts,while 3 constituents in Pu-erh tea have emerged as robust SARS-CoV-2 M^(pro)inactivators.
文摘This study explored the thermo-chemical properties of industrial hemp hurd with different provenances,maturity stages,and retting protocols.The findings were then compared to hemp hurd used in the fabrication of citric acid-bonded ultra-low-density hemp hurd particleboard.Pyrolysis-gas chromatography-mass spectrometry(Py-GC/MS),Fourier-transform infrared spectroscopy(FTIR),and thermogravimetric analysis(TGA)were employed to document the variability of the hurd and comprehend the potential impact on biobased composite applications.The choice of cultivar,maturity stage,and processing modality significantly influenced the chemical composition,presence of functional groups,and thermal stability of the hurd.Py-GC/MS revealed substantial variations in the lignin-to-carbohydrate(L/C)ratio,along with the absence of fatty acids in certain cultivars.While FTIR signals confirmed consistent functional groups,differences in peak intensities were indicative of carbohydrate variations associated with maturity and retting duration,impacting the availability of hydroxyl groups for,i.e.,interparticle bonding in citric acid-based bio-composites.Furthermore,it was observed that shorter retting durations initially enhanced the thermal resistance,but prolonged retting led to accelerated degradation,significantly reducing the hurd’s residual mass.The findings indicated notable differences among the samples,emphasizing the importance of investigating variables such as provenance/cultivar,maturity,and processing modality.This assessment is essential to ensure effective agronomic practices that align the raw material characteristics with the specific requirements of intended applications,such as the fabrication of biobased hemp hurd composites.
文摘Ozonolysis products of four lepidopteral pheromone were identified by methane CI-MS.The spectra obtained were notably simpler than those of EI-MS,the peak of molecular ion was normally close to the base peak,and the characteristic fragment ions were high in m/z,thereby the interpretation was facilitated.
基金National Science & Technology Mega Project forPrimary Drug Innovation from Ministry of Science and Technologyof China (Grant No. 2009ZX09502-006)
文摘This work aims to elucidate the chemical constituents of Kai-Xin-San（KXS） and its metabolites in rat plasma.KXS extracts were separated on an Agilent HPLC SB-C 18 column,analyzed by ion-trap tandem mass spectrometry and high-accuracy qTOF mass spectrometry in negative ion mode.A total of 39 compounds,including 11 ginsenosides,14 Polygala saponins,5 sucrose esters,8 oligosaccharide esters and 1 xanthone were characterized from KXS.Fifteen of them were confirmed by reference standards.No constituents were detected from Poria or Acori Tatarinowii Rhizoma.After oral administration of KXS（7 g/kg）,10 ginsenosides and 18 Polygala compounds were detected in rat plasma.This study indicates that ginseng saponins,Polygala saponins and saccharide esters could be the major effective components of KXS prescription.
基金National Natural Science Foundation of China(Grant No.81222054 and 21305005)the Program for New Century Excellent Talents in University from Chinese Ministry of Education(Grant No.NCET-11--0019)National Science and Technology Mega Project for Primary Drug Innovation of China(Grant No.2014ZX09304--307)
文摘An ultra high performance liquid chromatography coupled with hybrid quadrupole-orbitrap mass spectrometry （UHPLC-quadrupole-orbitrap MS） method was developed to systematically analyze chemical constituents of Scutellaria barbata D. Don. The 70% methanol extract was separated on an Agilent Eclipse Plus Cl8 column （1.8μm, 150 mm×2.1 mm）, and eluted with a gradient of methanol-acetonitrile-water containing 0.1% formic acid at a flow rate of 0.25 mL/min. Constituents were identified by HRMS in the negative ion mode using both full scan and two-stage threshold-triggered mass modes. A total of 56 compounds, including 20 free flavonoids, 20 flavonoid O-glycosides, 2 flavonoid C-glycosides, 4 phenylethanoid glycosides, and 10 phenolic compounds were identified by analyzing their high resolution mass spectral data. Among them, 8 flavonoids and 2 phenylethanoid glycosides were unambiguously identified by comparing with reference standards. This study demonstrates that hybrid quadrupole-orbitrap mass spectrometry is a powerful tool in structural identification of unknown compounds in comolicated herbal extracts.
文摘The project consists in the implementation of a biocomposite based on tannin resin and natural rubber matrices with the bast fibres of <i>Triumfetta cordifolia </i>A.Rich.“<i>Okong</i>” from the equatorial region of Cameroon as reinforcement. A study of this still little known fibre is necessary. This paper evaluates the physico-chemical and mechanical characteristics of the fibers. The fibers are extracted by us. A series of experiments is conducted for this purpose: morphological observation with a scanning electron microscope (SEM);density evaluation with a helium pycnometer;absorption rate evaluation according to the protocol available in the literature, Fourier Transform Infrared Spectrometry (FT-IR), chemical composition evaluation according to ASTM 1972 and ASTM 1977 standards, thermogravimetric analysis (TGA) and tensile tests on fiber bundles according to NF T25-501-3. The results show that the fiber is made up of several elementary fibers with oval cross-sections. A density of 1.477g/cm<sup>3</sup> close to that of hemp. These fibers have a water absorption rate of 342.5%, which correlates with the presence of free hydroxyl functional groups obtained from the spectrometry study (FT-IR). Chemical analysis reveals that the fiber is made up of celluloses (44.4%), hemicelluloses (30.8%), lignins (18.9%), pectins (3.3%), waxes (0.5%) and minerals (2.1%). In addition, we learn that the fibers studied dehydrate at 11.49%, showinga notable thermal stability around 235°C with a peak thermal decomposition of cellulose located at 420°C. In terms of mechanical behaviour, the results reveal that the fibers offer a Young’s modulus in traction of 12.4 ± 6.9 GPa, a tensile strength of 526 ± 128 MPa and an elongation at break of 2.25%. The information thus obtained makes it possible to place these fibers in the same fiber group as flax and jute. They could therefore be used for the same types of applications. They also inform us that these fibers can withstand the temperatures of composite shaping by thermocompression.
文摘For the handling, treatment and utilization of fly ash from biomass combustion its chemical composition and physical properties are important. In this study eight filter fly ashes from different grate-fired biomass combustion plants were investigated. In fly ash from straw combustion high concentrations of（K） were found, whereas in the fly ash from wood combustion the concentrations of Ca and Mg were higher. The average concentration of PO3-4was similar in both types of fly ashes. In all wood fly ashes some measured heavy metal concentrations were above the limits for utilization. The straw fly ashes were much less contaminated and can be utilized. For wood fly ash most parameters showed little variation, except from one fly ash where the dust pre-separator is in poor condition. The average values were： mass median diameter 4.3 ± 0.8 μm, spread of particle size distribution19 ± 11, particle density 2620 ± 80 kg/m^3 and angle of repose 50°± 1°. The density of the straw fly ashes is lower（2260 ± 80 kg/m^3） and the spread of the size distribution is higher（72 ± 24）.For one straw combustion fly ash the values of the mass median diameter and the angle of repose were similar to the values of wood combustion fly ash, for the other straw fly ash the values differed considerably. While the particle size of this fly ash was much smaller,surprisingly the angle of repose was also lower. This can be attributed to the formation of small agglomerates in this fly ash, which were not disintegrated without a certain stress.
基金The authors sincerely acknowledge the funding support from National Natural Science Foundation of China(51678251)Central University's Basic Research Business Fees Transformation and Cultivation Project(2018KZ001)Trademark or manufacturers'names appear in this paper only because they are considered essential to the object of this paper.
文摘SBS(styrene-butadiene-styrene block copolymer)has been widely used in pavement industry as an asphalt modifier.Nanomaterials can further enhance the performance of SBS modified asphalt.However,rare studies investigate the feasibility of using graphene as a performance enhancer of SBS modified asphalt.To fill this gap,comprehensive experimental tests including chemical and mechanical test were carried out on SBS-graphene modified asphalt and SEBS(styrene-ethylene-butylene-styrene block copolymer,which is a hydrogenated polymer of SBS)modified asphalt.Graphene with different dimensions and contents was taken into consideration in this study.Based on the experimental work,it can be concluded that graphene improves the mid-temperature performance of SBS modified asphalt.Compared with two-dimensional graphene,three-dimensional graphene has a greater advantage and the enhancement effect increases with the increase of its dosage.In addition,the cross-linked structure of SBS-graphene composite improves the distribution of SBS in asphalt,which improves the overall performance of SBS modified asphalt.
文摘To our knowledge,precise data concerning the pollution in terms of qualitative and quantitative fluctuations in discharge water from the laundry sector have seldom been reported.This study investigated the chemical composition of the discharge water from a laundry industry.Over 160 chemical substances and 15 standard water parameters were monitored.The results showed that the discharge water presented both inorganic and organic polycontamination with a high degree of qualitative and quantitative variability.However,of all monitored substances,only five metals(Al,Cu,Fe,Sr,and Zn),five minerals(P,Ca,K,Na,and S),and alkylphenols were systematically present and quantifiable.For a daily average water flow of 129 m^(3),the released metal flux was 356 g/d.Substances,such as trichloromethane,brominated diphenyl ether(BDE)47,and fluorides,were occasionally found and quantified.Other substances,such as chlorophenols,organo-tins,and pesticides were never identified.All the samples had quantifiable levels in the chemical oxygen demand(COD),biological oxygen demand(BOD),and hydrocarbons.Only the concentrations of Zn(8.3 g/d),Cu(21.4 g/d),and BOD(57.4 g/d)were close to or above the regulatory values:74.0 g/d for Zn,9.0 g/d for Cu,and 57.0 kg/d for BOD.The data obtained from this study are useful to the choice of additional treatments for the reduction of pollutant fluxes.
