Study of 1986 and 1987 heavy metal distribution in surface water of the Kuroshio area in the East China Sea showed regional and slight seasonal variations in distribution and concentration . Heavy metal levels in Taiw...Study of 1986 and 1987 heavy metal distribution in surface water of the Kuroshio area in the East China Sea showed regional and slight seasonal variations in distribution and concentration . Heavy metal levels in Taiwan Strait, the sea area north of Taiwan and the continental shelf are higher than those in the main axis of the Kuroshio . Dissolved Cu in summer and winter decreases with the increase of salinity , but dissolved Cd has no obvious change with salinity .展开更多
Color mothball is a daily necessity in Southeast Asia. Mothball contained nearly 100% naphthalene or 100% p-dichlorobenzene. It was used to resist insects, mothproof and mildew with a special odor. In other words, the...Color mothball is a daily necessity in Southeast Asia. Mothball contained nearly 100% naphthalene or 100% p-dichlorobenzene. It was used to resist insects, mothproof and mildew with a special odor. In other words, the odor was thought unpleasant enough to drive animals away in repellent products. This research analyzed color mothball which was manufactured by C and N companies. The mothball was dyed with eight dyes and three essences of fragrance, respectively. The experiment of color fastness with UV-light test is to determine how much the color will fade, when it exposed to a known ultraviolet light source. In the last analysis, the experimental data from the spectrum of GC/MS described all kinds of structure on color mothball after 80 hours phototherapy treatment as shown in the content. This research reveals that color mothball can have better appearance and greater performance, to meet the requirements for customs and various applications.展开更多
Efficient storage and handling facilities play a pivotal role in ensuring the quality and longevity of date palm produce. This study aims to contribute to the assessment of the operation of refrigeration units in the ...Efficient storage and handling facilities play a pivotal role in ensuring the quality and longevity of date palm produce. This study aims to contribute to the assessment of the operation of refrigeration units in the Drâa Tafilalet region through a diagnostic study conducted by surveying 12 date-packing units. Interviews and surveys were conducted among 12 date packaging units provided by the State to Economic Interest Groups (EIG) in the Drâa-Tafilalet region. Data focused on general EIG information, unit identification, a four-year operational overview, and 2021 palm date processing activities. To streamline analysis, units were categorized into two groups based on packaging capacity: Group 1 (≥400 tons) and Group 2 (<400 tons). The assessment revealed that the packaging units had enhanced this crucial link in the dating industry and introduced a new dynamic in the date marketing chain. However, operational expertise and optimal equipment utilization often fall short, with over 50% of the EIG failing to use provided equipment, except for cold storage rooms. The chain involves a series of operations to preserve the stored product’s intrinsic and extrinsic quality. Evaluated practices include fumigation, meticulous sorting to eliminate visually anomalous dates, calibration during packaging, and storage at temperatures ranging from 0 to 4˚C with humidity levels between 50 and 80%, varying based on the date’s nature (soft, dry, or semi-dry). Expertise in this process mitigates the risk of desiccation or excessive rehydration, preventing date fermentation. Finally, to reduce their energy consumption and solve the balance sheet deficit issue, the government has equipped all the date packaging units from Group 1 and one from Group 2 in the Daraa Tafilalet region with photovoltaic energy. The date packaging infrastructure has boosted the value of Moroccan dates, benefiting small-scale agriculture. Despite improved packaging quality and job creation, suboptimal equipment usage by over 50% of EIGs emphasizes the need for enhanced operational efficiency.展开更多
Dissolved organic matter(DOM)contains thousands of molecules and is key for biogeochemical cycles in aquatic and terrestrial ecosystems by interacting with microbes.Over the last decade,the study of DOM has been advan...Dissolved organic matter(DOM)contains thousands of molecules and is key for biogeochemical cycles in aquatic and terrestrial ecosystems by interacting with microbes.Over the last decade,the study of DOM has been advanced and accelerated with the developments of instrumental and statistical approaches.However,it is still challenging in statistical analyses,data visualization,and theoretical interpretations largely due to the complexity of molecular composition and underlying ecological mechanisms.In this study,we developed an R package iDOM with functions for the basic and advanced statistical analyses and the visualization of DOM derived from Fourier transform ion cyclotron resonance mass spectrometer(FT‐ICR MS).The package could handle various data types of DOM,including molecular compositional data,molecular traits,and uncharacterized molecules(i.e.,dark matter).It could integrate explanatory data,such as environmental and microbial data,to explore the relationships between DOM and abiotic or biotic drivers.To illustrate its use,we presented case studies with an example dataset of DOM and microbial communities under experimental warming.We included case studies of basic functions for the calculation of molecular traits,the assignment of molecular classes,and the compositional analyses of chemical diversity and dissimilarity.We further showed the case studies with advanced functions to quantify DOM assembly processes,assess the effects of dark matter on molecular interactions,analyze the ecological networks between DOM and microbes,and explore their response to warming.The source code and example dataset of iDOM are publicly available on https://github.com/jianjunwang/iDOM.We expect that iDOM will serve as a comprehensive pipeline for DOM statistical analyses and bridge the gap between chemical characterization and ecological interpretation in a theoretical framework.展开更多
An alkaline precipitation method was introduced to produce hydrous cerium oxides.The prepared powder was characterized by Brunauer-Emmett-Teller（BET） nitrogen adsorption-desorption,X-ray diffraction（XRD）,Fourier t...An alkaline precipitation method was introduced to produce hydrous cerium oxides.The prepared powder was characterized by Brunauer-Emmett-Teller（BET） nitrogen adsorption-desorption,X-ray diffraction（XRD）,Fourier transform infrared（FTIR） spectrometry,and thermal gravimetry（TG） approaches.The adsorbent has a chemical formula of CeO2·nH2O（n 2） and a cubic fluorite-type structure after high temperature treatment.Adsorption capacity of different temperature treated hydrous cerium oxides does not directly correlate with BET specific surface area.Phosphate adsorption isotherms follow the Langmuir equation below the treatment temperature of 800°C.Phosphate adsorption causes no change on the structure of a hydrous cerium oxides,and no signs of CePO4 precipitates are found.The ion-exchanging structure of hydrous cerium oxide plays a fundamental role in phosphate adsorption.The structure is highly temperature resistant and forms adsorption sites which adsorb both water and some anions.Complete loss of adsorption ability cannot be achieved unless the treatment temperature is higher than 1200°C.Mechanism study shows that the adsorption of phosphates is mainly an anion-exchange process.展开更多
With outstanding analytical performance and portability, miniature mass spectrometer is one of the most powerful tools for in-situ analysis. The miniaturization of mass spectrometers has lasted for more than ten years...With outstanding analytical performance and portability, miniature mass spectrometer is one of the most powerful tools for in-situ analysis. The miniaturization of mass spectrometers has lasted for more than ten years, during which a number of miniature mass spectrometers employing different techniques have been developed. Small-in-size, working at relatively high pressure region and capable of performing tandem mass spectrometry, ion trap is the most widely used mass analyzer in miniature mass spectrometer systems. The recent development of miniature ion trap mass spectrometer systems in the last ten years was reviewed in this paper. These instruments adopt different atmospheric pressure interfaces （APIs）, which are membrane inlets （MIs）, discontinuous atmospheric pressure interface （DAPI） and continuous atmospheric pressure interface （CAPI）. This review emphasizes on the mini mass spectrometry （MS） system that can be handheld by one person, but not the field-able ones that are too large to be hand-portable.展开更多
A new composition of Portland cement clinker was studied, in which KH, SM and IM was 0.98,2.4 and 2.4 respectively as well as its meal added 1%CuO （in mass）. Fired at 1 200℃,1 350℃,1 400℃ and 1 450℃ for 30 min, ...A new composition of Portland cement clinker was studied, in which KH, SM and IM was 0.98,2.4 and 2.4 respectively as well as its meal added 1%CuO （in mass）. Fired at 1 200℃,1 350℃,1 400℃ and 1 450℃ for 30 min, the resultant mineral phases component and mineral morphology were analyzed. The performances of the cement which was made of clinker burned at 1 450℃ and fly ash were determined. By means of QXRD, XRD and optical microscopy, it is shown that the clinker burnt at 1 450℃ has the larger size crystals and distinct crystal interface, in which the C3S content is 73.37% and the mineral phases is dominantly C3S, following by minor C2S, C3A and tetracalcium aluminoferrite. The results reveal that a new type of high C3S content clinker can completely be made by traditional temperature-time schedule. The performances of the cement produced from this clinker with addtion of 50% fly ash and 5% gupsum were in agreement with the 32.5 strength grade of Portland fly-ash cement. The results also show that the clinker has a significant effect of saving energy and utilizing waste slag.展开更多
To investigate the influence of extractable organic matter （EOM） on pore evolution of lacustrine shales, Soxhlet extraction, using dichloromethane, was performed on a series of Chang 7 shale samples （Ordos Basin, C...To investigate the influence of extractable organic matter （EOM） on pore evolution of lacustrine shales, Soxhlet extraction, using dichloromethane, was performed on a series of Chang 7 shale samples （Ordos Basin, China） with vitrinite reflectance of 0.64% to 1.34%. Low-pressure gas adsorption experiments were conducted on the samples before and after extraction. The pore structure parameters were calculated from the gas adsorption data. The results show complex changes to the pore volumes and surface areas after extraction. The pore development of both the initial and extracted samples is strongly controlled by total organic carbon （TOC） content. Micropores developed mainly in organic matter （OM）, while mesopores and macropores predominantly developed in fractions other than OM. The influence of EOM on micropores is stronger than on mesopores and macropores. Organic solvents with a higher boiling point should be used to explore the effect of EOM on pore structure in the future.展开更多
Most of the structural alloys’applications are under static,dynamic,and cyclic forms of loading.Ti-5553 alloy in the beta phase field is being investigated to confirm the mechanism of deformation and phase transforma...Most of the structural alloys’applications are under static,dynamic,and cyclic forms of loading.Ti-5553 alloy in the beta phase field is being investigated to confirm the mechanism of deformation and phase transformation upon quasi-static and dynamic compression.The Ti-5553 alloy was heat-treated at 900℃ (almost 50℃ above beta transus temperature)for one hour of soaking time followed by air quenching to achieve a fullyβphase field.After that,Dynamic compression(DC)by Split Hopkinson Pressure Bar(SHPB)and Quasi-static compression(QSC)were performed at a strain rate of~10^3)/s and 10^(-3)/s,respectively.Recovered specimens were thoroughly examined by using different tools,such as an Optical microscope(OM),Scanning electron microscope(SEM),High-resolution transmission electron microscope(HRTEM),and Electron backscatter diffraction(EBSD)to get the reliable data for justification of logical conclusions.It is found that the dominating mode of deformation was dislocation slip along with twinning({332}<113>)to some extent in both of QSC and DC,but sliding&spalling of the grain boundary is observed more in the former.Stress-induced phase transformation,i.e.,βtoα"andβtoω,took place in the grains saturated with dislocation slips,where the former transformation occurred simultaneously with{332}<113>twinning,whileβtoωtransformation was completed when a set of two adjacent(110)_(β)planes covered±1/6th of the total separation distance between two(next to each other)(111)_(β)planes,by equal but opposite shear in(111)_(β)direction,and it caused 3%shrinkage of two closed packed(110)_(β)planes after transformation.展开更多
Water regulation of the Xiaolangdi Reservoir of the Yellow River was chosen as a case to investigate variations in concentrations and bioavailability of heavy metals caused by water conservancy projects in rivers. Wat...Water regulation of the Xiaolangdi Reservoir of the Yellow River was chosen as a case to investigate variations in concentrations and bioavailability of heavy metals caused by water conservancy projects in rivers. Water and suspended sediment（SPS） samples were collected at downstream sampling sites along the river during this period. Concentrations and speciation of Zn, Cr, Cu, Ni, and Pb in water and SPS samples were analyzed, and their bioaccumulation was studied with Daphnia magna. This study indicated that the exchangeable and carbonatebound fractions of heavy metals in SPS decreased along the studied stretch, and the dissolved heavy metal concentrations increased along the river with 1.6–15 folds. This is because sediment resuspension increased along the river during water regulation, giving rise to the increase of heavy metal release from SPS. The dissolved Zn, Cu, Ni, and Pb concentrations were significantly positively correlated with SPS concentrations, and their increase along the river was greater than Cr. The body burdens of heavy metals in D. magna exposed into samples collected from the reservoir outlet were 1.3–3.0 times lower than those from downstream stations, suggesting that the heavy metal bioavailability increased during water regulation.This should be considered in the reservoir operation.展开更多
A new paradigm for ship detection in polarimetric synthetic aperture radar(Pol-SAR)image is presented.We firstly utilize the scattering similarity parameters to investigate the differences of scattering mechanism betw...A new paradigm for ship detection in polarimetric synthetic aperture radar(Pol-SAR)image is presented.We firstly utilize the scattering similarity parameters to investigate the differences of scattering mechanism between ships and sea clutter.Based on these differences,we propose a novel ship detection metric,denoted as the scattering similarity based metric(SSM),to conduct ship detection task.The distribution model of SSM metric is investigated and modeled by kernel density estimation(KDE).Based on the statistical distribution,an adaptive constant false alarm rate(CFAR)detection scheme is implemented.We compare the proposed SSM with two classic polarimetric metrics,i.e.,the polarimetric cross-entropy(PCE)and the reflection symmetry metric(RSM).The experimental results conducted on C-band RADARSAT-2 Pol-SAR data demonstrate the feasibility and advantage of the proposed SSM metric both in sea clutter modeling and in ship detection.展开更多
To investigate pore characteristics and the factors controlling lacustrine shales,geochemical,mineralogical and petrophysical experiments were performed on 23 shale samples from the Qingshankou Formation of the Songli...To investigate pore characteristics and the factors controlling lacustrine shales,geochemical,mineralogical and petrophysical experiments were performed on 23 shale samples from the Qingshankou Formation of the Songliao Basin,China.A comparison of mercury injection capillary pressure(MICP)and low-temperature N2 adsorption pore-size distribution showed that MICP has a higher pore-size distribution(PSD)line in its overlapping pore diameter range,which may be elevated by the higher pressure of MICP.Therefore,in the overlapping range,low-temperature N2 adsorption data were preferred in pore characterization.Negative correlations were observed between pore volumes and TOC content,indicating organic matter pores are not well-developed in the studied samples.This may be related to their low grade of maturity and type I kerogens.There existed negative relationships between pore volumes and S1,which illustrated that liquid hydrocarbons occupied some pore space.Micropore volume had a better correlation with S1 than mesopore and macropore volumes,which suggests that liquid hydrocarbons preferentially occur in micropores.No obvious relationships between pore volumes and quartz or feldspar were observed,while pore volumes increased with the increasing clay mineral content.These relationships indicate that intraparticle pores in clay minerals represent the principal pore type.展开更多
[Objectives] The aim of this work was to compare the inhibitory effects of different water-soluble extracts of ginseng on hydroxyl radical. [Methods]The water-soluble effective parts of ginseng were extracted by ortho...[Objectives] The aim of this work was to compare the inhibitory effects of different water-soluble extracts of ginseng on hydroxyl radical. [Methods]The water-soluble effective parts of ginseng were extracted by orthogonal test,the hydroxyl radical scavenging rate of each extract was determined by salicylic acid method,and the extraction process of the optimum hydroxyl radical inhibitor was optimized using variance analysis and cluster analysis. [Results] A total of 16 samples were prepared. Among them,the sample No. 12 had the highest hydroxyl radical scavenging rate,and the inhibition rate reached 105. 08% at the concentration of 1 g/L. [Conclusions] Ginseng water extract contained hydroxyl radical scavenger,of which the optimum extraction process was as follows: p H of 8,solid to liquid ratio of 1∶ 10,extraction temperature of 4℃,extraction time of 12 h and extraction times of 3.展开更多
The adsorption capacities of new humic acids isolated from Yakouren forest （YHA） and Sahara （Tamenrasset： THA） soils （Algeria） and commercial humic acid （PFHA） on polyaniline emeraldine base （PEB） were stud...The adsorption capacities of new humic acids isolated from Yakouren forest （YHA） and Sahara （Tamenrasset： THA） soils （Algeria） and commercial humic acid （PFHA） on polyaniline emeraldine base （PEB） were studied at pH 6.6. Also the adsorption of heavy metals such as Cd 2＋ , Zn 2＋ and Ni 2＋ on humic acid-polyaniline systems （HA-PEB） was investigated at the same conditions. HA-PEB compounds were characterized by scanning electron microscopy （SEM）, infrared spectrometry and cavity microelectrode. In addition, batch adsorption and cavity microelectrode were used in the adsorption study of Cd 2＋ , Zn 2＋ and Ni 2＋ on HA-PEB. To develop biocaptors of polluting metals using a cavity microelectrode modified by HA-PEB systems, the adsorption kinetic and adsorption capacity were investigated. The SEM analysis showed that the presence of humic acid affected the PEB surface and caused the formation of a granular morphology. The maximum adsorption capacities （q max ） of PFHA, THA and YHA determined by adsorption isotherms were 91.31, 132.1 and 151.0 mg/g, respectively. Batch adsorption results showed that q max of Cd 2＋ , Zn 2＋ and Ni 2＋ on HA-PEB followed the order： THA-PEB YHA-PEB PFHA-PEB. The voltammograms obtained with HA-PEB modified cavity microelectrode showed the appearance of new redox couples reflecting the adsorption of HA on PEB. Metal-humic acid-polyaniline voltammograms were characterized by appearance of oxidation-reduction couples or reduction wave corresponding to metal. Finally, the result may be exploited to develop a biocaptor based on the cavity microelectrode amended by THA-PEB and YHA-PEB.展开更多
Gaseous peroxides play important roles in atmospheric chemistry. To understand the pathways of the formation and removal of peroxides, atmospheric peroxide concentrations and their controlling factors were measured fr...Gaseous peroxides play important roles in atmospheric chemistry. To understand the pathways of the formation and removal of peroxides, atmospheric peroxide concentrations and their controlling factors were measured from 7：00 to 20：00 in September, October, and November 2013 at a heavily trafficked residential site in Beijing, China, with average concentrations of hydrogen peroxide（H2O2） and methyl hydroperoxide（MHP） at 0.55 ppb and 0.063 ppb, respectively. H2O2 concentrations were higher in the afternoon and lower in the morning and evening, while MHP concentrations did not exhibit a regular diurnal pattern. Both H2O2 and MHP concentrations increased at dusk in most cases. Both peroxides displayed monthly variations with higher concentrations in September. These results suggested that photochemical activity was the main controlling factor on variations of H2O2 concentrations during the measurement period. Increasing concentrations of volatile organic compounds emitted by motor vehicles were important contributors to H2O2 and MHP enrichment. High levels of H2O2 and MHP concentrations which occurred during the measurement period probably resulted from the transport of a polluted air mass with high water vapor content passing over the Bohai Bay, China.展开更多
The frequent haze days around the Chinese capital of Beijing in recent years have aroused great attention owing to the detrimental effects on visibility and public health. To discover the potential health effects of t...The frequent haze days around the Chinese capital of Beijing in recent years have aroused great attention owing to the detrimental effects on visibility and public health. To discover the potential health effects of the haze, oxidative capacities of airborne particles collected in Beijing during haze and clear days were comparably assessed by a plasmid scission assay. Eleven water-soluble trace elements （As, Cd, Cr, Cu, Mn, Ni, Pb, V, Se, T1, and Zn） in the size-segregated airborne particles were quantitatively analyzed by inductively coupled plasma mass spectrometry, and most of the water- soluble trace elements were found to mainly concentrate in the fine particle size of 0.56-1.0 μm. In comparison with clear days, the mass concentrations of 11 analyzed water-soluble trace elements remarkably increased during haze days, and the oxidative capacities determined by the plasmid scission assay were markedly elevated accordingly during the haze days under the same dosage of particles as for those during clear days. Water-soluble trace elements in airborne particles, such as Cu, V, and particularly Zn, were found to have significantly positive correlations with the plasmid DNA damage rates. Because Cu, V, and Zn have been considered as bioavailable elements, the evident increase of these elements during haze days may be greatly harmful to human health.展开更多
A series of cellulose 3,5-dimethylphenylcarbamates （CDMPCs） with different degrees of substitution （DS） and degrees of polymerization （DP） were homogeneously synthesized in 1-allyl-3-methylimidazolium chloride ...A series of cellulose 3,5-dimethylphenylcarbamates （CDMPCs） with different degrees of substitution （DS） and degrees of polymerization （DP） were homogeneously synthesized in 1-allyl-3-methylimidazolium chloride （AmimC1）. Then, the CDMPCs were coated on silica gel and used as chiral stationary phases （CSPs）, and their chiral recognition abilities for seven racemates were evaluated by high performance liquid chromatography. The results showed that DS and DP of CDMPCs had a great influence on chiral recognition abilities of the CSPs. The CSPs with the DS ~ 1 gives a low chiral recognition to most racemates. On the contrast, the CSPs with the DS _〉 2 exhibited high chiral separation abilities. For example, six racemates could be separated on the CSP with CDMPC of DS ~ 2 （CSP-2）. Especially, for the enantioseparation of 1-（2-naphthyl） ethanol and Tr6ger＇s base, CSP-2 gave the highest separation ability in all of CSPs. On the other hand, when the DP of cellulose was in a range from 39 to 220, the chiral separation abilities of CDMPCs increased as the DP increased. This work demonstrates that the structure of cellulose esters such as DS and DP has important effect on their chiral separation ability, and therefore provides a practical method to design and prepare desirable CSPs for different racemates.展开更多
A dust deflation module was developed and coupled with the air quality modeling system RAMS-CMAQ to simultaneously treat all the major tropospheric aerosols（i.e.,organic and black carbons,sulfate,nitrate, ammonia,soi...A dust deflation module was developed and coupled with the air quality modeling system RAMS-CMAQ to simultaneously treat all the major tropospheric aerosols（i.e.,organic and black carbons,sulfate,nitrate, ammonia,soil dust,and sea salt）.Then the coupled system was applied to East Asia to simulate Asian dust aerosol generation,transport and dry/wet removal processes during 14-25 March 2002 when two strong dust storms occurred consecutively.To evaluate model performance and to analyze the observed features of dust aerosols over the East Asian region,model results were compared to concentrations of suspended particulate matter of 10μm or less(PM;;1-h intervals) at four remote Japanese stations and daily air pollution index （API） values for PM;at four large Chinese cities.The modeled values were generally in good agreement with observed data,and the model reasonably reproduced two dust storm outbreaks and generally predicted the dust onset and cessation times at each observation site.In addition,hourly averaged values of aerosol optical thickness（AOT） were calculated and compared with observations at four Aerosol Robotic Network （AERONET） stations to assess the model’s capability of estimating dust aerosol column burden.Analysis shows that modeled and observed AOT values were generally comparable and that the contribution of dust aerosols to AOT was significant only with regard to their source regions and their transport paths.展开更多
A novel 2,6-dimethyl-b-CD bonded and silica based HPLC chiral stationary phase（CSP） was prepared.The diphenylmethane diisocyanate（MDI） was applied for the first time in the immobilization of 2,6-dimethyl-b-CD onto...A novel 2,6-dimethyl-b-CD bonded and silica based HPLC chiral stationary phase（CSP） was prepared.The diphenylmethane diisocyanate（MDI） was applied for the first time in the immobilization of 2,6-dimethyl-b-CD onto the surface of aminized silica gel under mild conditions. The composite materials obtained were used as the CSP for chiral separation processes and this kind of CSP exhibits good enantioselectivity for a variety of chiral compounds under reversed-phase conditions.展开更多
文摘Study of 1986 and 1987 heavy metal distribution in surface water of the Kuroshio area in the East China Sea showed regional and slight seasonal variations in distribution and concentration . Heavy metal levels in Taiwan Strait, the sea area north of Taiwan and the continental shelf are higher than those in the main axis of the Kuroshio . Dissolved Cu in summer and winter decreases with the increase of salinity , but dissolved Cd has no obvious change with salinity .
文摘Color mothball is a daily necessity in Southeast Asia. Mothball contained nearly 100% naphthalene or 100% p-dichlorobenzene. It was used to resist insects, mothproof and mildew with a special odor. In other words, the odor was thought unpleasant enough to drive animals away in repellent products. This research analyzed color mothball which was manufactured by C and N companies. The mothball was dyed with eight dyes and three essences of fragrance, respectively. The experiment of color fastness with UV-light test is to determine how much the color will fade, when it exposed to a known ultraviolet light source. In the last analysis, the experimental data from the spectrum of GC/MS described all kinds of structure on color mothball after 80 hours phototherapy treatment as shown in the content. This research reveals that color mothball can have better appearance and greater performance, to meet the requirements for customs and various applications.
文摘Efficient storage and handling facilities play a pivotal role in ensuring the quality and longevity of date palm produce. This study aims to contribute to the assessment of the operation of refrigeration units in the Drâa Tafilalet region through a diagnostic study conducted by surveying 12 date-packing units. Interviews and surveys were conducted among 12 date packaging units provided by the State to Economic Interest Groups (EIG) in the Drâa-Tafilalet region. Data focused on general EIG information, unit identification, a four-year operational overview, and 2021 palm date processing activities. To streamline analysis, units were categorized into two groups based on packaging capacity: Group 1 (≥400 tons) and Group 2 (<400 tons). The assessment revealed that the packaging units had enhanced this crucial link in the dating industry and introduced a new dynamic in the date marketing chain. However, operational expertise and optimal equipment utilization often fall short, with over 50% of the EIG failing to use provided equipment, except for cold storage rooms. The chain involves a series of operations to preserve the stored product’s intrinsic and extrinsic quality. Evaluated practices include fumigation, meticulous sorting to eliminate visually anomalous dates, calibration during packaging, and storage at temperatures ranging from 0 to 4˚C with humidity levels between 50 and 80%, varying based on the date’s nature (soft, dry, or semi-dry). Expertise in this process mitigates the risk of desiccation or excessive rehydration, preventing date fermentation. Finally, to reduce their energy consumption and solve the balance sheet deficit issue, the government has equipped all the date packaging units from Group 1 and one from Group 2 in the Daraa Tafilalet region with photovoltaic energy. The date packaging infrastructure has boosted the value of Moroccan dates, benefiting small-scale agriculture. Despite improved packaging quality and job creation, suboptimal equipment usage by over 50% of EIGs emphasizes the need for enhanced operational efficiency.
基金supported by the National Natural Science Foundation of China(42225708,U24A20578,42377122,92251304,and 42077052)Basic Research Program of Jiangsu Province(BK20240111)+2 种基金the Research Program of Sino‐Africa Joint Research Center,Chinese Academy of Sciences(151542KYSB20210007)Science and Technology Planning Project of NIGLAS(NIGLAS2022GS09)Key Laboratory of Lake and Watershed Science for Water Security(NKL2023‐QN04).
文摘Dissolved organic matter(DOM)contains thousands of molecules and is key for biogeochemical cycles in aquatic and terrestrial ecosystems by interacting with microbes.Over the last decade,the study of DOM has been advanced and accelerated with the developments of instrumental and statistical approaches.However,it is still challenging in statistical analyses,data visualization,and theoretical interpretations largely due to the complexity of molecular composition and underlying ecological mechanisms.In this study,we developed an R package iDOM with functions for the basic and advanced statistical analyses and the visualization of DOM derived from Fourier transform ion cyclotron resonance mass spectrometer(FT‐ICR MS).The package could handle various data types of DOM,including molecular compositional data,molecular traits,and uncharacterized molecules(i.e.,dark matter).It could integrate explanatory data,such as environmental and microbial data,to explore the relationships between DOM and abiotic or biotic drivers.To illustrate its use,we presented case studies with an example dataset of DOM and microbial communities under experimental warming.We included case studies of basic functions for the calculation of molecular traits,the assignment of molecular classes,and the compositional analyses of chemical diversity and dissimilarity.We further showed the case studies with advanced functions to quantify DOM assembly processes,assess the effects of dark matter on molecular interactions,analyze the ecological networks between DOM and microbes,and explore their response to warming.The source code and example dataset of iDOM are publicly available on https://github.com/jianjunwang/iDOM.We expect that iDOM will serve as a comprehensive pipeline for DOM statistical analyses and bridge the gap between chemical characterization and ecological interpretation in a theoretical framework.
基金support from the National Natural Science Foundation of China (No.20876157)
文摘An alkaline precipitation method was introduced to produce hydrous cerium oxides.The prepared powder was characterized by Brunauer-Emmett-Teller（BET） nitrogen adsorption-desorption,X-ray diffraction（XRD）,Fourier transform infrared（FTIR） spectrometry,and thermal gravimetry（TG） approaches.The adsorbent has a chemical formula of CeO2·nH2O（n 2） and a cubic fluorite-type structure after high temperature treatment.Adsorption capacity of different temperature treated hydrous cerium oxides does not directly correlate with BET specific surface area.Phosphate adsorption isotherms follow the Langmuir equation below the treatment temperature of 800°C.Phosphate adsorption causes no change on the structure of a hydrous cerium oxides,and no signs of CePO4 precipitates are found.The ion-exchanging structure of hydrous cerium oxide plays a fundamental role in phosphate adsorption.The structure is highly temperature resistant and forms adsorption sites which adsorb both water and some anions.Complete loss of adsorption ability cannot be achieved unless the treatment temperature is higher than 1200°C.Mechanism study shows that the adsorption of phosphates is mainly an anion-exchange process.
基金supported by the National Natural Science Foundation of China (Nos. 21475010, 61635003)Beijing Natural Science Foundation (No. 16L00065)State Key Laboratory Explosion Science and Technology (No. YBKT16-17)
文摘With outstanding analytical performance and portability, miniature mass spectrometer is one of the most powerful tools for in-situ analysis. The miniaturization of mass spectrometers has lasted for more than ten years, during which a number of miniature mass spectrometers employing different techniques have been developed. Small-in-size, working at relatively high pressure region and capable of performing tandem mass spectrometry, ion trap is the most widely used mass analyzer in miniature mass spectrometer systems. The recent development of miniature ion trap mass spectrometer systems in the last ten years was reviewed in this paper. These instruments adopt different atmospheric pressure interfaces （APIs）, which are membrane inlets （MIs）, discontinuous atmospheric pressure interface （DAPI） and continuous atmospheric pressure interface （CAPI）. This review emphasizes on the mini mass spectrometry （MS） system that can be handheld by one person, but not the field-able ones that are too large to be hand-portable.
基金Funded by 973 National Key Scientific Project Foundation (No.001CB610701) the University Key Laboratoty Foundation of Jiangshu Province (No.KJS03021)the Sixth Outstanding Talents Foundation.
文摘A new composition of Portland cement clinker was studied, in which KH, SM and IM was 0.98,2.4 and 2.4 respectively as well as its meal added 1%CuO （in mass）. Fired at 1 200℃,1 350℃,1 400℃ and 1 450℃ for 30 min, the resultant mineral phases component and mineral morphology were analyzed. The performances of the cement which was made of clinker burned at 1 450℃ and fly ash were determined. By means of QXRD, XRD and optical microscopy, it is shown that the clinker burnt at 1 450℃ has the larger size crystals and distinct crystal interface, in which the C3S content is 73.37% and the mineral phases is dominantly C3S, following by minor C2S, C3A and tetracalcium aluminoferrite. The results reveal that a new type of high C3S content clinker can completely be made by traditional temperature-time schedule. The performances of the cement produced from this clinker with addtion of 50% fly ash and 5% gupsum were in agreement with the 32.5 strength grade of Portland fly-ash cement. The results also show that the clinker has a significant effect of saving energy and utilizing waste slag.
基金funded by the National Science Foundation of China(41502144,41503034)the Foundation of the State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum,Beijing(No.PRP/open-1612)+2 种基金the Fund of the Education Department of Sichuan Province(16ZA0075)the Youth Scientific Innovation Team of Hydrocarbon Accumulation and Geochemistry,Southwest Petroleum University(2015CXTD02)the Sichuan Province University Scientific Innovation Team Construction Project(USITCP)
文摘To investigate the influence of extractable organic matter （EOM） on pore evolution of lacustrine shales, Soxhlet extraction, using dichloromethane, was performed on a series of Chang 7 shale samples （Ordos Basin, China） with vitrinite reflectance of 0.64% to 1.34%. Low-pressure gas adsorption experiments were conducted on the samples before and after extraction. The pore structure parameters were calculated from the gas adsorption data. The results show complex changes to the pore volumes and surface areas after extraction. The pore development of both the initial and extracted samples is strongly controlled by total organic carbon （TOC） content. Micropores developed mainly in organic matter （OM）, while mesopores and macropores predominantly developed in fractions other than OM. The influence of EOM on micropores is stronger than on mesopores and macropores. Organic solvents with a higher boiling point should be used to explore the effect of EOM on pore structure in the future.
基金the financial assistance of the State Key Laboratory of explosion science and technology China (Grant No.YBKT17-06)
文摘Most of the structural alloys’applications are under static,dynamic,and cyclic forms of loading.Ti-5553 alloy in the beta phase field is being investigated to confirm the mechanism of deformation and phase transformation upon quasi-static and dynamic compression.The Ti-5553 alloy was heat-treated at 900℃ (almost 50℃ above beta transus temperature)for one hour of soaking time followed by air quenching to achieve a fullyβphase field.After that,Dynamic compression(DC)by Split Hopkinson Pressure Bar(SHPB)and Quasi-static compression(QSC)were performed at a strain rate of~10^3)/s and 10^(-3)/s,respectively.Recovered specimens were thoroughly examined by using different tools,such as an Optical microscope(OM),Scanning electron microscope(SEM),High-resolution transmission electron microscope(HRTEM),and Electron backscatter diffraction(EBSD)to get the reliable data for justification of logical conclusions.It is found that the dominating mode of deformation was dislocation slip along with twinning({332}<113>)to some extent in both of QSC and DC,but sliding&spalling of the grain boundary is observed more in the former.Stress-induced phase transformation,i.e.,βtoα"andβtoω,took place in the grains saturated with dislocation slips,where the former transformation occurred simultaneously with{332}<113>twinning,whileβtoωtransformation was completed when a set of two adjacent(110)_(β)planes covered±1/6th of the total separation distance between two(next to each other)(111)_(β)planes,by equal but opposite shear in(111)_(β)direction,and it caused 3%shrinkage of two closed packed(110)_(β)planes after transformation.
基金supported by the National Key R&D Program of China(No.2017YFA0605001)the National Natural Science Foundation of China(No.91547207)the Fund for Innovative Research Group of the National Natural Science Foundation of China(No.51721093)
文摘Water regulation of the Xiaolangdi Reservoir of the Yellow River was chosen as a case to investigate variations in concentrations and bioavailability of heavy metals caused by water conservancy projects in rivers. Water and suspended sediment（SPS） samples were collected at downstream sampling sites along the river during this period. Concentrations and speciation of Zn, Cr, Cu, Ni, and Pb in water and SPS samples were analyzed, and their bioaccumulation was studied with Daphnia magna. This study indicated that the exchangeable and carbonatebound fractions of heavy metals in SPS decreased along the studied stretch, and the dissolved heavy metal concentrations increased along the river with 1.6–15 folds. This is because sediment resuspension increased along the river during water regulation, giving rise to the increase of heavy metal release from SPS. The dissolved Zn, Cu, Ni, and Pb concentrations were significantly positively correlated with SPS concentrations, and their increase along the river was greater than Cr. The body burdens of heavy metals in D. magna exposed into samples collected from the reservoir outlet were 1.3–3.0 times lower than those from downstream stations, suggesting that the heavy metal bioavailability increased during water regulation.This should be considered in the reservoir operation.
基金The National Natural Science Foundation of China under contract No.61471024the National Marine Technology Program for Public Welfare under contract No.201505002。
文摘A new paradigm for ship detection in polarimetric synthetic aperture radar(Pol-SAR)image is presented.We firstly utilize the scattering similarity parameters to investigate the differences of scattering mechanism between ships and sea clutter.Based on these differences,we propose a novel ship detection metric,denoted as the scattering similarity based metric(SSM),to conduct ship detection task.The distribution model of SSM metric is investigated and modeled by kernel density estimation(KDE).Based on the statistical distribution,an adaptive constant false alarm rate(CFAR)detection scheme is implemented.We compare the proposed SSM with two classic polarimetric metrics,i.e.,the polarimetric cross-entropy(PCE)and the reflection symmetry metric(RSM).The experimental results conducted on C-band RADARSAT-2 Pol-SAR data demonstrate the feasibility and advantage of the proposed SSM metric both in sea clutter modeling and in ship detection.
基金co-funded by the National Science Foundation of China(41972161,41502144)the Petro China Science and Technology Special Project(2011A-0203)。
文摘To investigate pore characteristics and the factors controlling lacustrine shales,geochemical,mineralogical and petrophysical experiments were performed on 23 shale samples from the Qingshankou Formation of the Songliao Basin,China.A comparison of mercury injection capillary pressure(MICP)and low-temperature N2 adsorption pore-size distribution showed that MICP has a higher pore-size distribution(PSD)line in its overlapping pore diameter range,which may be elevated by the higher pressure of MICP.Therefore,in the overlapping range,low-temperature N2 adsorption data were preferred in pore characterization.Negative correlations were observed between pore volumes and TOC content,indicating organic matter pores are not well-developed in the studied samples.This may be related to their low grade of maturity and type I kerogens.There existed negative relationships between pore volumes and S1,which illustrated that liquid hydrocarbons occupied some pore space.Micropore volume had a better correlation with S1 than mesopore and macropore volumes,which suggests that liquid hydrocarbons preferentially occur in micropores.No obvious relationships between pore volumes and quartz or feldspar were observed,while pore volumes increased with the increasing clay mineral content.These relationships indicate that intraparticle pores in clay minerals represent the principal pore type.
基金Supported by Open Foundation of Key Laboratory of Ministry of Education for TCM Viscera-State Theory and Applications,Liaoning University of Traditional Chinese Medicine(ZYZX1709)Project of Education Department of Liaoning Province(L201606)China Postdoctoral Science Foundation(2013M530945)
文摘[Objectives] The aim of this work was to compare the inhibitory effects of different water-soluble extracts of ginseng on hydroxyl radical. [Methods]The water-soluble effective parts of ginseng were extracted by orthogonal test,the hydroxyl radical scavenging rate of each extract was determined by salicylic acid method,and the extraction process of the optimum hydroxyl radical inhibitor was optimized using variance analysis and cluster analysis. [Results] A total of 16 samples were prepared. Among them,the sample No. 12 had the highest hydroxyl radical scavenging rate,and the inhibition rate reached 105. 08% at the concentration of 1 g/L. [Conclusions] Ginseng water extract contained hydroxyl radical scavenger,of which the optimum extraction process was as follows: p H of 8,solid to liquid ratio of 1∶ 10,extraction temperature of 4℃,extraction time of 12 h and extraction times of 3.
文摘The adsorption capacities of new humic acids isolated from Yakouren forest （YHA） and Sahara （Tamenrasset： THA） soils （Algeria） and commercial humic acid （PFHA） on polyaniline emeraldine base （PEB） were studied at pH 6.6. Also the adsorption of heavy metals such as Cd 2＋ , Zn 2＋ and Ni 2＋ on humic acid-polyaniline systems （HA-PEB） was investigated at the same conditions. HA-PEB compounds were characterized by scanning electron microscopy （SEM）, infrared spectrometry and cavity microelectrode. In addition, batch adsorption and cavity microelectrode were used in the adsorption study of Cd 2＋ , Zn 2＋ and Ni 2＋ on HA-PEB. To develop biocaptors of polluting metals using a cavity microelectrode modified by HA-PEB systems, the adsorption kinetic and adsorption capacity were investigated. The SEM analysis showed that the presence of humic acid affected the PEB surface and caused the formation of a granular morphology. The maximum adsorption capacities （q max ） of PFHA, THA and YHA determined by adsorption isotherms were 91.31, 132.1 and 151.0 mg/g, respectively. Batch adsorption results showed that q max of Cd 2＋ , Zn 2＋ and Ni 2＋ on HA-PEB followed the order： THA-PEB YHA-PEB PFHA-PEB. The voltammograms obtained with HA-PEB modified cavity microelectrode showed the appearance of new redox couples reflecting the adsorption of HA on PEB. Metal-humic acid-polyaniline voltammograms were characterized by appearance of oxidation-reduction couples or reduction wave corresponding to metal. Finally, the result may be exploited to develop a biocaptor based on the cavity microelectrode amended by THA-PEB and YHA-PEB.
基金supported by the International Cooperation Project of MOST(No.2012DFG90290)the National Natural Science Foundation of China(No.4225001046)+1 种基金National Department Public Benefit Research Foundation(No.201509014)the Basic Foundation for Public Benefit-Research Academies from Centre Government(No.2010KYYW02)
文摘Gaseous peroxides play important roles in atmospheric chemistry. To understand the pathways of the formation and removal of peroxides, atmospheric peroxide concentrations and their controlling factors were measured from 7：00 to 20：00 in September, October, and November 2013 at a heavily trafficked residential site in Beijing, China, with average concentrations of hydrogen peroxide（H2O2） and methyl hydroperoxide（MHP） at 0.55 ppb and 0.063 ppb, respectively. H2O2 concentrations were higher in the afternoon and lower in the morning and evening, while MHP concentrations did not exhibit a regular diurnal pattern. Both H2O2 and MHP concentrations increased at dusk in most cases. Both peroxides displayed monthly variations with higher concentrations in September. These results suggested that photochemical activity was the main controlling factor on variations of H2O2 concentrations during the measurement period. Increasing concentrations of volatile organic compounds emitted by motor vehicles were important contributors to H2O2 and MHP enrichment. High levels of H2O2 and MHP concentrations which occurred during the measurement period probably resulted from the transport of a polluted air mass with high water vapor content passing over the Bohai Bay, China.
基金supported by the"Strategic Priority Research Program-Formation Mechanism and Control Strategies of Haze in China"of the Chinese Academy of Sciences(No.XDB05010100),the National Basic Research Program(973)of China(No.2013CB228503,2010CB732304)
文摘The frequent haze days around the Chinese capital of Beijing in recent years have aroused great attention owing to the detrimental effects on visibility and public health. To discover the potential health effects of the haze, oxidative capacities of airborne particles collected in Beijing during haze and clear days were comparably assessed by a plasmid scission assay. Eleven water-soluble trace elements （As, Cd, Cr, Cu, Mn, Ni, Pb, V, Se, T1, and Zn） in the size-segregated airborne particles were quantitatively analyzed by inductively coupled plasma mass spectrometry, and most of the water- soluble trace elements were found to mainly concentrate in the fine particle size of 0.56-1.0 μm. In comparison with clear days, the mass concentrations of 11 analyzed water-soluble trace elements remarkably increased during haze days, and the oxidative capacities determined by the plasmid scission assay were markedly elevated accordingly during the haze days under the same dosage of particles as for those during clear days. Water-soluble trace elements in airborne particles, such as Cu, V, and particularly Zn, were found to have significantly positive correlations with the plasmid DNA damage rates. Because Cu, V, and Zn have been considered as bioavailable elements, the evident increase of these elements during haze days may be greatly harmful to human health.
基金financially supported by the National Natural Science Foundation of China(Nos.5110316721174151 and 51425307)
文摘A series of cellulose 3,5-dimethylphenylcarbamates （CDMPCs） with different degrees of substitution （DS） and degrees of polymerization （DP） were homogeneously synthesized in 1-allyl-3-methylimidazolium chloride （AmimC1）. Then, the CDMPCs were coated on silica gel and used as chiral stationary phases （CSPs）, and their chiral recognition abilities for seven racemates were evaluated by high performance liquid chromatography. The results showed that DS and DP of CDMPCs had a great influence on chiral recognition abilities of the CSPs. The CSPs with the DS ~ 1 gives a low chiral recognition to most racemates. On the contrast, the CSPs with the DS _〉 2 exhibited high chiral separation abilities. For example, six racemates could be separated on the CSP with CDMPC of DS ~ 2 （CSP-2）. Especially, for the enantioseparation of 1-（2-naphthyl） ethanol and Tr6ger＇s base, CSP-2 gave the highest separation ability in all of CSPs. On the other hand, when the DP of cellulose was in a range from 39 to 220, the chiral separation abilities of CDMPCs increased as the DP increased. This work demonstrates that the structure of cellulose esters such as DS and DP has important effect on their chiral separation ability, and therefore provides a practical method to design and prepare desirable CSPs for different racemates.
基金supported by the National Basic Research Program of China(2007CB407303)the Knowledge Innovation Program of the Chinese Academy of Sciences (KZCX2-YW-Q11-04)the National Natural Science Foundation of China(Grant No.41005064).
文摘A dust deflation module was developed and coupled with the air quality modeling system RAMS-CMAQ to simultaneously treat all the major tropospheric aerosols（i.e.,organic and black carbons,sulfate,nitrate, ammonia,soil dust,and sea salt）.Then the coupled system was applied to East Asia to simulate Asian dust aerosol generation,transport and dry/wet removal processes during 14-25 March 2002 when two strong dust storms occurred consecutively.To evaluate model performance and to analyze the observed features of dust aerosols over the East Asian region,model results were compared to concentrations of suspended particulate matter of 10μm or less(PM;;1-h intervals) at four remote Japanese stations and daily air pollution index （API） values for PM;at four large Chinese cities.The modeled values were generally in good agreement with observed data,and the model reasonably reproduced two dust storm outbreaks and generally predicted the dust onset and cessation times at each observation site.In addition,hourly averaged values of aerosol optical thickness（AOT） were calculated and compared with observations at four Aerosol Robotic Network （AERONET） stations to assess the model’s capability of estimating dust aerosol column burden.Analysis shows that modeled and observed AOT values were generally comparable and that the contribution of dust aerosols to AOT was significant only with regard to their source regions and their transport paths.
文摘A novel 2,6-dimethyl-b-CD bonded and silica based HPLC chiral stationary phase（CSP） was prepared.The diphenylmethane diisocyanate（MDI） was applied for the first time in the immobilization of 2,6-dimethyl-b-CD onto the surface of aminized silica gel under mild conditions. The composite materials obtained were used as the CSP for chiral separation processes and this kind of CSP exhibits good enantioselectivity for a variety of chiral compounds under reversed-phase conditions.
