针对直流微电网中多个储能单元在补充或吸收系统功率的过程中,由于自身初始荷电状态(SOC)不同而出现的过充过放问题以及传统下垂控制法不能实时合理分配储能系统负荷电流的不足,为此研究开发一种新的基于蓄电池SOC幂指数的下垂控制方法.与传统方法的不同在于该方法能够根据SOC幂指数的变化实时改变下垂系数,使蓄电池SOC和负荷电流达到均衡状态.通过对SOC控制特性进行分析选出SOC幂指数控制算法的合理参数n=2、p=7.蓄电池充、放电以及负载波动时的自动充放电过程Matlab/Simulink仿真计算结果显示,所提方法能够有效均衡2组蓄电池的负荷电流与SOC,且电压波动幅度控制在允许范围内.

Arsenic (As) contamination of environmental water has attracted much attention in recent years, due to its high mobility and various species. In this work, water samples collected from Chenjiang, Liuyang, and Xiangjiang River, the most heavily As‐contaminated rivers in China, were investigated using size exclusion chromatography (SEC), combined with inductively coupled plasma mass spectrometry (ICP‐MS), as well as three‐dimensional excitation‐emission matrix (3DEEM) fluorescence spectroscopy coupled with parallel factor analysis (PARAFAC). By EEM‐PARAFAC modeling, all EEM peaks could be decomposed into a five‐component model including: one fulvic acid‐like component, one tryptophan‐like component, and three humic‐like components. Using SEC‐ICP‐MS, arsenite, arsenate, arsenobetaine, and DOM‐bound As were eluted and detected according to different molecular weights, and the co‐elution of 56Fe and DOM‐bound As under the same elution condition indicated the complexation between DOM and As through Fe ions. Furthermore, obvious quenching effects of fluorescent DOM components in the presence of As(III) were observed, suggesting that strong complexation or adsorption occurred between As(III) and different DOM components. Among five DOM components identified by PARAFAC, the humic‐like components played a key role in forming complexes with As(III), thus leading to the changes of As species in natural water. The results exhibited considerable implications for the role of DOM components on the mobilization and speciation of As, which could be applied to the As removal in natural water and act as an indicator to evaluate the capacity of As complexation or adsorption in the environment.

A quick and simple ultra-high performance supercritical fluid chromatography-photodiode array detector method was developed and validated for the simultaneous determination of 9 carotenoids in dietary supplements. The influences of stationary phase, co-solvent, pressure, temperature and flow rate on the separation of carotenoids were evaluated. The separation of the carotenoids was carried out using an Acquity UPC(2) HSS C18 SB column (150mm×3.0mm, 1.8μm) by gradient elution with carbon dioxide and a 1:2 (v:v) methanol/ethanol mixture. The column temperature was set to 35°C and the backpressure was 15.2MPa. Under these conditions, 9 carotenoids and the internal standard, β-apo-8'-carotenal, were successfully separated within 10min. The correlation coefficients (R(2)) of the calibration curves were all above 0.997, the limits of detection for the 9 carotenoids were in the range of 0.33-1.08μg/mL, and the limits of quantification were in the range of 1.09-3.58μg/mL. The mean recoveries were from 93.4% to 109.5% at different spiking levels, and the relative standard deviations were between 0.8% and 6.0%. This method was successfully applied to the determination of 9 carotenoids in commercial dietary supplements.

An ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method has been developed to identify and determine 11 industrial antioxidants in the aqueous simulants. A ProElut PLS SPE column was used for the enrichment, and an ACQUITY UPLC BEH C18 UPLC column (100 mm x 2.1 mm, 1.7 μm) was used for separation by the gradient elution with pure water and acetonitrile as the mobile phases. The MS/MS detection was performed with an electrospray ionization (ESI) source in negative mode. The external standard method was used for quantitation in the present study. The linear ranges of the 11 analytes were from 5.0 to 100 μg/L. The coefficients of correlation were greater than 0.995. The recoveries of blank aqueous simulants fortified with the 11 analytes at the levels of 5.0, 10.0 and 20.0 μg/L were 61.4% to 109.4% with the relative standard deviations varied from 3.9% to 18.2% (n = 6). The LODs and LOQs of the 11 analytes in aqueous simulants were 0.2-1.0 μg/L and 0.5-3.0 μg/L, respectively. This method is highly sensitive and accurate, and can be applied to the determination of the 11 trace industrial antioxidants in the aqueous simulants.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

A method was established for the determination of six compounds of zearalanol and related mycotoxins in pork and its products. After hydrolysis of the target compounds in the pork by beta-glucosidase/sulfatase, they were extracted with methanol aqueous solution and further purified by an HLB column. The separation was performed on a BEH C18 column with gradient elution using acetonitrile-water as mobile phases. The analytes were determined by mass spectrometry using electrospray ionization (ESI) in negative scan mode and multiple reaction monitoring (MRM) mode. alpha-Zearalenol-D7 and beta-zearalenol-D7 were used as internal standards. The good linearities (r > 0. 999) were achieved for the six compounds over the range of 1. 0 - 100 microg/L based on the internal standard calibration. The detection limits of the method were 0.03 -0.09 microg/kg. The mean recoveries of the six target compounds spiked at three levels from 1. 0 - 10. 0 microg/kg ranged from 76. 7% to 100. 5% with the relative standard deviations (RSDs) less than 20%. The proposed method is simple, sensitive, reproducible, and complies with the regulations for the determination of trace contaminant residues in food matrice.

Ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/ MS) combined with solid phase extraction (SPE) has been developed for the determination of 7 microcystins (MCs) in Spirulina health food products. The sample was extracted by 70% (v/v) methanol. The lipid substances were isolated by centrifugation under freezing condition, and then followed by clean-up with a Waters Oasis HLB solid phase extraction cartridge. The separation was performed on a Waters ACQUITY UPLC BEH C18 column with gradient elution using acetonitrile and 0.2 mmol/L ammonium acetate. The electrospray ionization (ESI) source in positive ion mode was used for multiple reaction monitoring (MRM). The external standard method was used for the quantification. The linear ranges for 7 MCs were 20 - 400 microg/kg, and the correlation coefficients were not less than 0.995. The limits of detection were 6.7 - 33.3 microg/kg. The limits of quantification were 20.0 - 100.0 microg/kg. The recoveries of the 7 MCs spiked in blank Spirulina samples ranged from 87.5% to 97.9% with the relative standard deviations of 1.6% - 6.9%. The results demonstrated that the method is easy, fast, sensitive, and suitable for the confirmation and quantification of the 7 MCs in Spirulina samples.

A validated method based on solid-phase extraction and ultra high-performance liquid chromatography–triple quadrupole tandem mass spectrometry, with electrospray ionization operated in the positive ion mode and multiple reaction monitoring, was developed for the determination of nicotine in Solanaceae vegetables. Sample preparation involved liquid–solid extraction, centrifugation, filtration, and solid-phase extraction. Two kinds of solid-phase extraction adsorbents, based on different retention mechanisms, were investigated. Relatively higher recoveries were obtained with a hydrophilic–lipophilic-balanced cartridge. A deuterated internal standard was used for quantification. The limit of quantification (LOQ) of nicotine in different vegetables was found to be between 0.07 and 0.5 μg/kg. The nicotine levels in the vegetable samples were above the LOQs. The method described here is thus suitable for the analysis of large sample batches, because it provides accurate quantification, high sensitivity and rapid chromatographic separation with facile preparation. The solid-phase extraction cartridges and organic solvents used in this work are easy to obtain, enabling the application of this method in most analytical laboratories.

Cerium(Ce),lanthanum(La),praseodymium(Pr) and neodymium(Nd) of rare earth ferrosilicon and rare earth ferrosilicon magnesium alloy were determined by inductively coupled plasma atomic emission spectrometric method(ICP-AES).The recoveries of each element were in the range of 88.0%—106.8%.The method is fast and simple with high sensitivity,and the repeatability and reproducibility can meet the detection requirement of each element.

Microcystins (MCs) produced by blue-green algae, is one of the algal toxins with features of highest frequency and production. MCs could cause serious multi-organ toxicity, genetic toxicity and carcinogenicity. Monitoring of MCs residue in aquatic products is important for evaluating the potential risk for human beings. Therefore, the trace analytical technique of MCs is needed. In this paper, the progress of the microcystins extraction, purification and analytical techniques is reviewed.

A method based on high performance liquid chromatography coupled with inductively coupled plasma mass spectrometry ( HPLC-ICP-MS) for simultaneous determination of organotin complexes (dibutyitin (DBT), tributyitin (TBT), diphenyitin (DPhT) and triphenyitin (TPhT) in marine sediments was established. After evaluation of different additives in the mobile phase, the use of 0.05% (V/V) of triethylamine (TEA) in a mobile phase of acetonitrile-water-acetic acid (50:38: 12) allowed the best chromatographic separation of the four compounds. The analytes were extracted into an extractant (V(acetonitrile):V (water):V (acetic acid) =55:33:12) with 5% TEA by using an ultrasonic bath (30 min). The extracted efficiency of organotin compounds in PACS-2 certified reference material was found the highest (>91.5%) and its recoveries were over 96%. The detection limits for DBT, TBT, DPhT and TPhT were 0.7, 0.75, 0.45 and 0.4 mu g/kg, respectively. Four mixed organotin standards ranging from 0.5 to 100 mu g/kg were used for the method evaluation. The experimental results indicated that the regression coefficient for each compound was over 0.998. Organotin compounds in marine sediments and aquatic products were analyzed via the new established method. It was found that the dominate species in marine sediments were DBT and TBT, while TBT and TPhT were detected in aquatic products.

A specific method for the determination of bromine and iodine species in drinking water was developed by using high performance liquid chromatography‐ICP‐MS. An ICS‐A23 ion chromatography column was chosen for the separation of species, with the mobile phase being 0.03 mol l−1 ammonium carbonate at a flow rate of 0.8 ml min−1. The detection limits for BrO3−, Br−, IO3− and I− were 0.032, 0.063, 0.008 and 0.012 μg l−1, respectively. Spectroscopic interferences were only observed in blank samples and mainly resulted from the argon‐potassium polyatomic ion (40Ar39K+). However, this interference was negligible because of the elution and complete separation from that of iodinate under optimised conditions. The method developed was successfully applied to twenty‐two samples of drinking water obtained from a supermarket. Results indicated that 36.4% of the samples had BrO3− concentrations exceeding the Chinese national limit for drinking water of 10 μg l−1.

Environmental context.Iodine in the atmosphere plays an important role in troposphere ozone destruction and climate change. However, cycling of atmospheric iodine is still poorly understood because of uncertainties in iodine speciation in aerosols. Here we report iodine levels and speciation in marine aerosols collected along a cruise path from Shanghai to the Arctic Ocean. Abstract.Total iodine (TI) and water-soluble iodine species in the total suspended particle samples collected onboard a round-trip cruise from Shanghai, China to the Arctic Ocean were measured using inductively coupled plasma mass spectrometry and ion chromatography–inductively coupled plasma mass spectrometry respectively. TI and total soluble iodine (TSI) levels varied considerably both spatially and temporally over the length of the voyage. The maximum iodine levels occurred in the Arctic Ocean in September, whereas the minimum levels occurred in the Western and Northern Pacific Ocean in July. Iodate (IO3 –) was found to be the dominant species in most samples, accounting for 57.8% of TSI on average, whereas iodide and soluble organic iodine only accounted for 16.8% of TSI on average. There was also a significant fraction of insoluble iodine. This finding confirms model predictions of atmospheric iodine speciation, i.e. the predominant iodine species is iodate rather than iodide.

The bromine and iodine species in aerosol samples were extracted using ultrapure water ultrasonic method with different extraction time and using pressurizing decomposition with dilute ammonia. The efficiency of the extraction and the stability of bromine and iodine species were compared under different extraction conditions. The results showed that (1) the efficiency of extraction using pressurizing decomposition, which might destroy some unknown form of organic iodine, was relatively higher than those using ultrasonic method; (2) I− was unstable in added standard cellular blank filter during ultrasonic-assisted extraction for long time; and (3) the optimum condition was ultrapure water ultrasonic-assisted extraction for 5 min. Moreover, the suitability of glass microfiber filter (GF) and cellular filter (CF) during extraction for bromine and iodine species in aerosol was also compared, which indicated that GF is favorable for species analysis compared with CF under different kinds of extraction conditions. Based on the extraction results, HPLC-ICPMS approach was developed to analyze bromine and iodine species in atmospheric aerosol. The total iodine, bromine, and their species in the aerosol samples collected from Hefei were then determined accordingly. The levels of total bromine and iodine in Hefei aerosols were 883 and 231 pmol m−3, respectively. Br−was found to be dominant species with 68%, while BrO3− was undetectable. 70% of total iodine occurred as unidentified forms including soluble organic iodine and insoluble iodine.

Iodine in the atmosphere directly influences on many kinds of photochemical reactions in troposphere, and indirectly poses impact on global climate change. It is thus that the research on the mechanism of atmospheric chemistry of iodine has attracted more and more attention. Iodine compounds in the aerosol are the final product of atmospheric chemistry reactions of iodine, which can be inferred and known via investigating the iodine speciation in aerosol. IO3- is often considered to be the dominant form of iodine precipitation. But field measurement in recent years showed that soluble organic iodine or I- were mostly the dominant forms in atmospheric aerosol. This implies that atmospheric chemistry mechanism of iodine still remain to perfect further. Here we focus on the research progress of atmospheric chemistry of iodine and its speciation in aerosols up to date.

Total iodine (TI) and water-soluble iodine species in the total suspended particle samples collected onboard a round-trip cruise from Shanghai, China to the Arctic Ocean were measured using inductively coupled plasma mass spectrometry and ion chromatography-inductively coupled plasma mass spectrometry respectively. TI and total soluble iodine (TSI) levels varied considerably both spatially and temporally over the length of the voyage. The maximum iodine levels occurred in the Arctic Ocean in September, whereas the minimum levels occurred in the Western and Northern Pacific Ocean in July. Iodate (IO3-) was found to be the dominant species in most samples, accounting for 57.8% of TSI on average, whereas iodide and soluble organic iodine only accounted for 16.8% of TSI on average. There was also a significant fraction of insoluble iodine. This finding confirms model predictions of atmospheric iodine speciation, i.e. the predominant iodine species is iodate rather than iodide.

A simple quantitative method was established for the determination of BrO3- and Br- in flour using high performance liquid chromatography-inductively coupled plasma mass spectrometry. ICS-A23 ion chromatography column was selected as separation column and the mobile phase was 0.03 mol/L ammonium carbonate at flow rate of 0.8 mL/min. The detection limits for BrO3- and Br- were 0.052 mu g/L and 0.048 mu g/L, respectively. Three sample preparation methods had been compared including ultrasonic, bathing, and oscillation extraction method. Oscillation method was selected finally. The recoveries of BrO3- and Br- were between 93% and 111%. The sum of bromine speciation was in accordance with the standard reference. The bromine speciation of 10 kinds of flour bought from the local supermarket was detected using this method.

The method based on the coupling of size-exclusion high-performance liquid chromatography with inductively coupled plasma-mass spectrometry was used for speciation analysis of cadmium binding nonprotein thiols in extracts of Indian mustard (Brassica Juncea). In the presence of Cd stress, Phytochelatins (PCs) were induced, and Cd ions in extracts were associated with the induced PCs. Four different Cd species of PC3-Cd, PC2-Cd, GSH-Cd, and Cys-Cd were detected in samples, which demonstrated that PCs were enzymatically synthesized from glutathione (GSH, Glu-Cys-Gly) by the constitutive enzyme PC syntheses. The results indicated that GSH-Cd exists as the main specie in leaf samples, whereas PC2-Cd is the main specie in root samples. A nonoxidizing (Nitrogen) preparation environment and a −70°C preservation condition were used to avoid the oxidation of sulfhydryl groups.

Objective:To establish a real-time fluorescent quantitative reverse transcription polymerase chain reaction(RT-PCR)to detect FOXP3 mRNA expression in human peripheral blood mononuclear cells(PBMCs)and to investigate the correlations between activity of CD4+CD25+ regulatory T cells and expression of FOXP3 mRNA.Methods:Total RNA was extracted with Trizol from human PBMCs and mRNA was transcribed reversely into cDNA.Real-time fluorescent quantitative RT-PCR with β-actin as the internal control gene was used to detect the expression levels of FOXP3 mRNA in 29 pediatric patients with asthma and 24 age-matched healthy children.The specificity of PCR productions was identified with the dissociation curves and agarose gel electrophoresis.Flow cytometry analysis was used to assess the percentage of CD4+CD25+regulatory T cells.The correlation between the expression and activity was analyzed.Results:The percentages of CD4+CD25+ regulatory T cells in group of asthma were significantly lower than those in group of control(P0.01),so did the expressions of FOXP3 mRNA(P0.05).The analysis of dissociation curves on FOXP3 and β-actin showed that both of them had only one simple spike and the Tm values were 82.4 ℃ and 87.8 ℃,respectively.The agarose gel electrophoresis of them showed only single PCR product each.Conclusion:It is an easy and reliable test to detect the expression level of FOXP3 mRNA by SYBR GreenⅠreal-time fluorescence quantitative RT-PCR and the preliminary experimental result shows that the percentages of CD4+CD25+ regulatory T cells and the expressions of FOXP3 mRNA have the same trend and confirms the correlation between them.

微型蒸渗仪作为测量土壤蒸发的有效手段之一,因其成本低、操作简便、应用广泛等优点得到广大研究人员的青睐。而微型蒸渗仪的制作材料、长度、直径、封底等都会影响测量结果的精确度,通过参阅多年来国内外学者对微型蒸渗仪的研究与使用进展状况,对影响微型蒸渗仪精度的一些因素作了简要分析。