Pesticides play an irreplaceable role in ensuring increased food production and income, but the overuse of pesticides can also pose a threat to food and environmental safety. A novel dual-emission fluorescent probe was developed for the facile and accurate detection of sulfonylurea herbicides. A Fo center dot rster resonance energy transfer system, based on N-doped carbon dots (N-CDs) and thioglycolic acid-capped cadmium telluride quantum dots (TGA-CdTe QDs) as energy donor-acceptor pairs, was established using graphitic carbon nitride (g-C3N4) as a substrate and successfully applied for the micro-detection of mesosulfuron-methyl (Mes). The CDs-CdTe/C3N4 probe exhibits emission peaks at 445 and 593 nm with strong fluorescence intensity under single-wavelength excitation. Mes was shown to significantly decrease the fluorescence intensity of each emission peak via different quenching mechanisms, and the degree of quenching was proportional to Mes concentration. The linear range of fluorescence measurement was 0-90 mu M, with limits of detection at 1.3 mu M (445 nm) and 0.8 mu M (593 nm). The dual-emission fluorescent probe exhibited excellent selectivity for Mes compared with the other eleven herbicides. The fluorescent probe has a satisfying detection performance in environmental water samples and wheat samples, and has potential application in the portable detection of pesticide residues.

In this study, we synthesized simple, cheap, and stable nitrogen (N)-doped carbon quantum dots (N-CQDs) from Moringa oleifera roots. The N-CQDs exhibited an intense blue fluorescence and a quantum yield (QY) of up to 43.4%. When excited at 350 nm, the highest generated wavelength was observed at 445 nm. These N-CQDs were then successfully used to detect sulcotrione (limit of detection = 2 μg/mL); the method was reliable and exhibited good feasibility for measurements in real samples. When the N-CQDs concentration was 11.0 μL/mL, inhibitory rates against the pathogens, Corynespora cassiicola and Phytophtora nicotianae were 82.8% and 75.3%, respectively. To investigate N-CQDs safety for plant growth, different concentrations were investigated using sorghum seedlings, with N-CQDs exhibiting very low toxicity toward plant growth. Thus, these findings provide a basis for the development of N-CQDs as green pesticides.

Derivatives of oxazine dyes were synthesized on mulitigram scales via efficient synthetic strategies. One practical route was selected to prepare compounds 6, 9 and 10, especially water-soluble compound 6 was obtained in better yield than reported, and compound 10 was insoluble in aqueous media in absence of phenolic-OH. Compounds 3 and 9 were found to be clear pH-dependent between pH = 4.0 and 10.0, and could be used as acid-base indicators to measure intracellular pH. Compounds 6, 9, 10 all have carboxylic acid functionalities, which could be activated and used to conjugate the dyes to biomolecules. In addition, compounds 6 and 9 with good solubility in aqueous media were used to develop a simple, quick, safe, highly sensitive staining method to detect PHAs-producing bacteria on heat-fixed smears, which was confirmed by fluorescence images of PHAs granules of bacteria.

Two new double-sided and multi-layered network porous compound named 1 [Ni-2(BTC)(2)(DABCO)(DEA)(2)] have been synthesized by solvent thermal synthesis method. Which, for the first time, exhibit an unusual double-sided and multi-layered MOF. The double-sided MOF structure extended to regular hexagon morphology in accordance with schematic representation of the 2D topological net of 1 and also confirmed by the SEM images. The N-2 and H-2 sorption certified it can be used as gas absorption.

Presented here is a metastable MOF built from the alternating connection of dodecahedral and cubic cages. Three different activation treatments, vacuum-drying, freeze-benzene drying and SCD activation, were performed to optimize the porosity and gas uptakes of the metastable MOF.

聚乙二醇以其优异的相变储能特性成为相变材料领域的研究热点.讨论了聚乙二醇相变温度、相变焓特点,综述了用于制备聚乙二醇基储能相变材料的可行方法,并对聚乙二醇基储能相变材料制备方法的发展前景进行了展望.

Monodisperse fluorescent poly(N-isopropyl acrylamide-co-acrylic acid) microgels doped with quantum dots (QDs) were fabricated as follows. First, cysteamine-capped cadmium telluride (CA-CdTe) QDs were introduced into the microgels at pH 7 by electrostatic interactions. Afterward, the CA-CdTe QDs were further immobilized in the microgels by the collapse of the polymer network when the pH of solution was adjusted to 4. In this system, there existed multiple interactions between the CA-CdTe QDs and the microgels, including hydrogen bonds, electrostatic interactions, and coordination bonds. The photoluminescence intensity and maximum emission wavelength of the resulting microgels could be easily adjusted by changes in the content of the CA-CdTe QDs in the hybrid microgels (HMs) and with differently sized QDs, respectively. We found that the lower the addition of CA-CdTe QDs was, the bigger the blueshift of the photoluminescence spectra of the HMs was and the weaker the photoluminescence intensity was. Finally, temperature-responsive emission of the HMs was examined. (c) 2015 Wiley Periodicals, Inc.

The purpose of this paper is to develop maleate improvers and additive,based on the mechanisms improving cold flow property of diesel fuel and the characteristics of biodiesel.The terpolymer AAS was prepared by copolymerizing maleic anhydride(MA),acrylamide(AM) and styrene and the preparation conditions were optimized using orthogonal experiments.CF was prepared with cyclohexanol and fatty acids.The products obtained were identified by IR,and its cold flow property evaluated.The best preparation conditions:n(MA):n(AM):n(S)=2:1.5:0.75,initiator BPO 1.5%(based on total mass of monomers,mass),copolymerization temperature 75℃,copolymerization time 5 h,catalyst dosage 1.0%(base on total mass of alcohol,mass),n(MA):n(alcohol)= 7:12,alcoholysis time 3 h.When AAS dosage was 0.3%(base on based oil,mass),the CFPP drop of biodiesel from soybean oil was 4℃.When AAS mixed with CF in mass ratio of 1:1,the CFPP of biodiesel from soybean oil and biodiesel from rapeseed oil could be reduced by 6℃and 5℃ respectively.

A kind of solid–solid phase change materials (SSPCMs), melamine/formaldehyde/polyethylene glycols (MFPEG) crosslinking copolymers, was synthesized referring to the reaction mechanism and conditions of amine–aldehyde condensation reaction and aldolization. The composition and chemical structure, thermophysical and crystallographic properties of MFPEG crosslinking copolymers were investigated by Fourier transform infrared spectroscopy (FT-IR), 1H nuclear magnetic resonance spectrometer (1H NMR), differential scanning calorimetry (DSC), thermogravimetry analysis system (TGA), wide-angle X-ray diffraction (WXRD) and polarization optical microscopy (POM). The results indicate that MFPEGs crosslinking copolymers possess excellent phase change properties and an applicable temperature range. The maximal latent heat enthalpies of heating and cooling cycle are 109.4 and 103.9 J/g, respectively. The decomposing temperature range of MFPEGs is about 340–455 °C in nitrogen atmosphere.

Ethylene-vinyl acetate copolymer is widely used as commercial pour point depressants (PPDs) all over the world. The authors describe four commercial PPDs for evaluating the sensitivity of Daqing diesel fuels. The content and carbon number distribution of n-alkanes in the Daqing diesel fuels were analyzed by high-temperature gas-phase chromatography. The structures of the commercial PPDs were confirmed by IR spectra. The results indicate that the n-alkanes carbon distributions display an obvious normal distribution in the Daqing diesel fuels. Commercial PPDs can maximumly depress cold filter plugging point of the tested diesel samples by 7 degrees C, 3 degrees C, 5 degrees C, and 0 degrees C, respectively. The distributions of high carbon n-alkanes are all narrow so that wax crystals precipitate more easily at low temperatures, and as a result, the interaction between PPD molecules and wax crystal molecules is not good.

The polyethylene glycol is a kind of phase change energy storage material with small thermal hysteresis effect, the phase change enthalpy and phase transition temperature varies with its different molecular weight. This article summarizes polyethylene glycol as research progress of phase change energy storage material, which mainly discusses the preparation methods and outlook about form-stable phase change materials.

Polyethylene glycol(PEG)/methyl cellulose(MC) form-stable phase change materials (PCMs) were prepared by solution-casting method with PEG as the energy storage material and MC as the support. The PEG leaking performance, crystal morphology, molecular structure and thermal properties of PEG/MC were characterized by means of constant temperature heating, polarized light microscopy (PLM), ATR-FTIR and DSC. The results indicated that the PEG/MC form-stable PCMs with PEG content less than 80.0% (w) didn't leak PEG when the environmental temperature was higher than the melting point of PEG and lower than 80°C; MC and PEG were well compatible because of hydrogen-bond action; when heating or cooling PEG/MC form-stable PCMs, it could store or release latent heat through the melting or crystallizing of PEG crystals.

The authors synthesized methacrylic acid ester (AE) monomers by direct esterification of methacrylic acid and fatty alcohols using paratoluene sulfonic acid as catalyst, hydroquinone as polymerization inhibitor, and toluene as solvent. Then, methacrylic acid ester-maleic anhydride (AM) copolymers were prepared by solution free radical copolymerization with benzoyl peroxide as initiator. The structures of the monomer and copolymer were confirmed by IR. Differential scanning calorimetry (DSC) was selected as the research method to investigate the wax formation process in the lube oils without and with adding AM. The results show that it possess the best solidification point depression (Delta SP) when the molar ratio of the reaction materials is 3:1 and the polydispersity is 1.81. It can execute a maximum depression of solidification point (SP) of the tested lube oils by 29, 21, and 20 degrees C, respectively. The AM additive has little effect on the total amount of wax, but just shift the precipitation toward lower temperature.

Adding pour point depressants (PPDs) to depress the cold filter plugging point (CFPP) of diesel has been widely used in the petroleum industry. This article describes the synthesis and evaluation of the performance of dialkylfumarate-styrene-vinyl acetate terpolymer (FSV) for improving the cold flow performance of the tested diesel fuels. The n-alkanes carbon distribution in the tested diesel samples was analyzed by gas-phase chromatography. The structures of the monomer and terpolymer were confirmed by infrared (IR) and H-1 nuclear magnetic resonance (NMR). In order to investigate the wax formation process in diesel fuels before and after adding FSV, differential scanning calorimetry was selected as research method. The results indicate that the cold flow performance is the best using a mixture of higher carbon alcohols in the esterification reaction and the molar ratio of the reaction materials should be 1:2:1. When the dosage of FSV is 0.08 wt%, it can depress CFPP of the two diesel samples by 1 degrees C and 4 degrees C, respectively.

The amidolysis derivatives (AMV-a) of the terpolymers (AMV) made by methacrylate ester, maleic anhydride and vinyl acetate were synthesized and used as cold flow improver for diesel fuels. The effects of chain length of fatty amine used in amidolysis on the cold filter plugging point depression (ACFPP) were discussed. The sensitivity of different kinds of diesel fuels to AMV-a, the synergism of AMV-a with typically commercial pour point depressants and the mechanism of ACFPP were investigated. It was shown that the ACFPP of Zhangjiagang 0~# diesel was 6℃ and the ACFPP of Shengli haike 5~# diesel was 4℃ both with addition of 0.08% AMV-a. The AMV-a showed favorable sensitivity to diesel fuels from different production areas, and the synergism of AMV-a with three typically commercial pour point depressants, respectively, could improve the low temperature performance of diesel fuels significantly.

In the practice of petroleum industry, adding cold flow improver (CFI) to lower the fuel's cold filter plugging point (CFPP) is an effective and economic way for improving the cold flow performance of diesel fuel. This paper described the synthesis and evaluation of the performance of dibehenyl fumarate-vinyl acetate (FV) copolymer for improving the cold flow performance of the tested diesel fuels. The carbon distribution in n-alkanes of the tested diesel samples were analyzed by gas phase chromatography. The structure of the copolymer was confirmed by the H-1 NMR spectroscopy. The wax crystals morphologies with and without adding the FV additive were investigated by means of polarizing microscope. The test results indicated that the FV additive could depress CFPP of the tested diesel samples by 2 degrees C and 4 degrees C, respectively, when dosage of the additive was 0.08 m%. The additive can modify the size and shape of the wax crystals and inhibit the formation of larger wax crystal lattices.

采用自由基溶液聚合法合成了α-甲基丙烯酸混合醇酯（AE）-马来酸酐（MA）-苯乙烯（St）三元共聚物（AMS）降凝剂;考察了AMS的最佳聚合条件及其对中原0#柴油和燕化0#柴油的降滤效果;用GC技术分析了中原0#柴油和燕化0#柴油中正构烷烃碳数的分布;用1HNMR技术表征了AE和AMS的结构。AMS的最佳聚合条件为:n（AE）∶n（MA）∶n（St）=3∶1∶1,时间5h,温度80℃;AMS降凝剂的适宜添加量（占柴油的质量分数）为0.08%,此时中原0#柴油和燕化0#柴油的冷滤点降幅分别为4℃和6℃。对于正构烷烃含量较低、正构烷烃碳数分布较宽且较均匀的柴油,使用AMS降凝剂时,降滤效果较好。

The mechanism of maleic anhydride-vinyl acetate-higher amine terpolymer (MV-a) as the pour point depressant for diesel oil was explored preliminarily by using infrared spectrometry(IR),differential scanning calorimeter(DSC) and dynamic light scattering(DLS) methods.The IR adsorption peak area ratios of A1363/A1377 and A722/A733 were increased remarkably for the wax sample separated from diesel oil with MV-a added,compared with that of wax sample without MV-a,showing that the structure of wax crystal was varied obviously.The co-crystallization of wax crystal and MV-a molecules might be the mechanism of cold filter plugging point reduction for diesel oil.If the peak areas and slopes of DSC curves reduced obviously for the diesel oil with MV-a added compared with that without MV-a,it will be better for the cold filter plugging point reduction of diesel oil.The colloidal dispersion was formed when the grain diameter of MV-a in diesel oil was less than 1000 nm,and the cold filter plugging point depression was better,too.