[Characteristics of the Size Distribution of Water-soluble Ions During a Heavy Pollution Episode in the Winter in Tianjin].

To characterize the size distribution of water-soluble inorganic ions (WSⅡ) during a heavy pollution episode, particle samples were collected by an Andersen cascade sampler in Tianjin in January 2014, and the concentrations of eight WSⅡ (Na+, NH4+, K+, Mg2+, Ca2+, Cl-, NO3-, and SO42-) during a typical haze episode were analyzed by ion chromatography. The sources and formation mechanisms of WSⅡ were analyzed based on their size distributions. The results showed that the daily average concentrations of PM2.5 and PM10 were (138±100) µg·m-3 and (227±142) µg·m-3, respectively, and the average concentration of total WSⅡ concentrations (TWSⅡ) in the coarse and fine particles were (34.07+6.16) µg·m-3 and (104.16+51.76) µg·m-3, respectively. The concentrations of SO42-, NO3-, and NH4+ in the fine particles were much higher than concentrations of the other ions, and there were strong correlations between these three ions. The TWSⅡ on clear days, light pollution days, and heavy pollution days were (41.55±12.41) µg·m-3, (94.46±31.19) µg·m-3, and (147.55±27.76) µg·m-3, respectively. On clear days, SO42- showed a unimodal distribution, peaking at 0.43-0.65 µm; and NO3- showed a trimodal distribution, peaking at 0.43-0.65 µm, 2.1-3.3 µm, and 5.8-9.0 µm. NH4+ had a bimodal distribution, peaking at 0.43-0.65 µm and 4.7-5.8 µm. On heavy pollution days, however, the size distributions of these three secondary inorganic ions switched to a unimodal size distribution, peaking at 0.65-1.1 µm. Unimodal NH4+ mainly coexisted with SO42- and NO3-, and the excess NH4+ was found to be combined with Cl- in the fine particles. In the coarse particles, NH4+ completely coexisted with SO42- and NO3-.

[Concentration Characteristics and Sources of Trace Metals in PM2.5 During Wintertime in Beijing].

To study the characteristics and sources of trace metals in PM2.5 during wintertime in Beijing, PM2.5 samples were collected from December 2014 to January 2015 by a middle volume sampler in the urban area of Beijing for 30 consecutive days. The mass concentration of PM2.5 was measured by filter membrane weighting method, and 16 kinds of trace metals were determined by inductively couple plasma-mass spectrometry (ICP-MS). In addition, the pollution characteristics and sources of trace metals were analyzed by enrichment factor (EF) method and factor analysis, respectively. The results showed that the concentrations of five elements (i. e. K, Ca, Fe, Al and Mg) accounted for 90.7% of the total metal elements. The concentrations of the metal elements changed obviously between day and night. Compared with daytime, crustal elements like Mg and Al decreased by more than 30% while anthropogenic elements like Cu and Pb increased by more than 40% in nighttime. Although the concentrations of metal elements increased by nearly one time in heavy pollution days compared with clean days, the mass percent of which in PM2.5 decreased from 10.9% in clean days to 4.6% in heavy pollution days. This result suggested the accumulation of metal elements in heavy pollution days had a minor contribution to the increased mass concentration of PM2.5. As the pollution episode progressed, anthropogenic elements (Cu,Zn,As,Se,Ag and Cd) increased faster than crustal elements (Al,Mg,Ca,Mn and Fe), which showed ratios ranging from 2.9 to 5.3 for anthropogenic elements and ratios ranging from 1.2 to 1.8 for crustal elements, when compared between heavy pollution days and clean days. In addition, the EF value of anthropogenic elements was also increased in the pollution days, indicating the concentrations of these elements was further influenced by the anthropogenic sources. Factor analysis showed that metal elements of PM2.5 during wintertime of Beijing were mainly from coal combustion and biomass burning, motor vehicle and industry emissions, and re-suspension of road dust, with the contributions of 34.2%,25.5% and 17.1%, respectively.

[Characteristics of the Size Distribution of Water Soluble Inorganic Ions During a Typical Haze Pollution in the Autumn in Shijiazhuang].

To characterize the size distribution of water soluble inorganic ions (WSⅡ) in haze days, particle samples were collected by an Andersen cascade impactor in Shijiazhuang from October 15 to November 14 in 2013, and the concentrations of eight kinds of WSⅡ (Na+, NH4+, K+, Mg2+, Ca2+, Cl-, NO3-and SO42-) during a typical haze episode were analyzed by ion chromatography. Sources and formation mechanism of WSⅡ were analyzed based on their size distributions. The results showed that Shijiazhuang suffers serious air pollution during the autumn season. The daily average concentrations of PM10and PM2.5were (361.2±138.7) µg·m-3 and (175.6±87.2) µg·m-3 and the daily average concentration of PM2.5was 2.3 times as high as the national secondary standard. The total water soluble inorganic ion concentrations (TWSⅡ) in clean days, light haze days and heavy haze days were(64.4±4.6)µg·m-3, (109.9±22.0)µg·m-3 and (212.9±50.1) µg·m-3 respectively. In addition, the ratio of secondary inorganic ions (SNA:SO42-, NO3- and NH4+) in TWSⅡ increased from 44.9% to 77.6% as changed from clean days to the heavy haze days, suggesting the evolution of haze episodes mainly originated from the formation and accumulation of SNA. The size distributions of SO42-, NO3- and NH4+ were bimodal in clean days, peaking at 0.43 -0.65 µm and 4.7-5.8 µm, respectively, which changed to unimodal distribution in both the light and heavy haze days, peaking at 0.65-1.1 µm. Owing to high humidity during the heavy haze days, the aqueous phase reactions of SO42- and NO3- were likely promoted, which led to the transformation of condensation mode in clean days to the droplet mode in haze days. The size distributions of Na+, Mg2+ and Ca2+ were different with that of SNA, which showed a coarse mode peaking at 4.7-5.8 µm both in clean and haze days, whereas K+and Cl- showed a bimodal distribution both in clean and haze days, although the modal size was different in clean and haze days.

Near-infrared fluorescence of π-conjugation extended benzothiazole and its application for biothiol imaging in living cells.

Two new π-conjugation extended benzothiazole derivatives bearing single (2) or double (3) vinyl groups between benzothiazolyl and 4-methylphenol moieties in 2,6-dibenzothiazolyl-4-methylphenol (1) have been synthesized and their photophysical properties were studied. In nonpolar solvents, 2 showed a keto tautomer emission from the excited state intramolecular proton transfer (ESIPT) at 626 nm, remarkably red-shifted compared to the keto tautomer fluorescence of 1 (568 nm), whereas 3 only exhibited an enol emission at 420 nm. However, a near-infrared (NIR) emission at 616/688 nm for 2/3 from the deprotonated anionic species was observed in polar solvents, which is farther red-shifted compared to that for deprotonated 1 (516 nm). With the aid of computational studies, the experimental observations were rationalized according to the efficient extension of π-conjugation of the molecular backbones in 2 and 3. Furthermore, a white emission with a broad band between 400 and 800 nm from 3 was also observed in a polar-nonpolar solvent mixture, where nearly pure white coordinates (0.33, 0.35) from the CIE chromaticity diagram were successfully achieved. By masking the phenol group in 3, a NIR fluorescent probe (4) for biothiols was constructed, which allows for imaging applications in living cells.

[The decipher, annotation and textual researches of 7 anti-dysentery prescriptions in the Tangut medical documents unearthed in Khara-Khoto].

There were 7 anti-dysentery prescriptions in the Tangut medical documents unearthed in Khara-Khoto, preserved in Russia, which were deciphered, annotated and textually researched based on the Tangut tool books like Wenhai (Word Ocean), Tongyin (Homophones), and Fan han he shi zhang zhong zhu (A Tangut-Chinese Timely Gem Dictionary), combining with classical medical documents and application of knowledge of ancient Chinese language. It can be sure that these prescriptions came from the central plains of China during the Song Dynasty, which were made use of by the prescriptions as they were by the physicians of the Western Xia regime, either made modifications and adjustments or without any change. For example, local foods like local sugar and cheese were added. As for the administration and dosage, again, they were applied by following the original one or changing a little according to the local diet customs.