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Based on 5-nitroisophthalic acid (5-H2nip) and bis(4-pyridyl)amine (dpa), the complexes {[Cd6(5-nip)6(dpa)4]·EtOH}n (1) and [Co5(5-nip)2(dpa)2(OH)2(SO4)2(H2O)2]n (2) have been synthesized and characterized by elemental analysis, single-crystal X-ray diffraction, IR spectroscopy, thermal gravimetry analysis, fluorescence and magnetic susceptibility. The carboxylate groups of the 5-nip2− adopt three different bridging modes [bis(chelate-bidentate), bis(bidentate) and bis(monodentate)]. The 5-nip2− anions and dpa play as linkers, which connect Cd(II) or Co(II) ions to form the three-dimensional structures of 1 and 2. Moreover, 1 exhibits intense solid-state luminescence emissions centered at 402 nm at room temperature, which mainly originates from the intraligand π–π* transitions of 5-nip2−. Magnetic susceptibility measurement indicates that 2 shows antiferromagnetic interactions between the Co(II) ions.

Four new coordination polymers, {[Mn3(BTC)2(4-pp)6(H2O)2]·(4-pp)2(H2O)2}n 1, [Cu3(BTC)2(dpa)2]n 2, {[Zn3(BTC)2(4-pp)6]·(H2O)}n 3, and [Ag2(HBTC)(Pz)1/2]n 4, were synthesized under pH-controlled sol...

Porous carbons (PCS) derived from sodium lignin sulfonate were activated by four common metal salts. The samples exhibit distinct characteristics of irregular, sunflower-like, interconnected sheet, and tine block morphologies under the impact of NaCl, CaCl2, ZnCl2, and FeCl3, respectively (PCS-MClx). Surprisingly, the maximum and minimum specific surface areas are 1524 and 44 m2/g corresponding to PCS-ZnCl2 and PCS-NaCl. All of the samples have plentiful functional groups; herein, PCS-NaCl and PCS-FeCl3 are detected with the highest O and S contents (11.85, 1.08%), respectively, which signifies sufficient active sites for adsorption. These porous materials were applied in toluene adsorption from paraffin liquid and matched the Langmuir isotherm models well. Thus, the activation mechanism was discussed in detail. PCS-MClx has a completely different pyrolysis behavior according to thermogravimetry/derivative thermogravimetry (TG/DTG) analysis. It is speculated that H[ZnCl2(OH)] would have an etching effect on the carbon structure of PCS-ZnCl2, and HCl or H2SO4, resulting from FeCl3 hydrolysis and a reduction reaction, would be corrosive to the sodium lignin sulfonate (SLS) surface. Each metal salt plays a different role in activation. The devised method for the synthesis of porous carbons is green and economical, which is suited to mass production.

Herein, polypyrrole-based porous carbon (PPC) was prepared by ZnCl2 activation for toluene adsorption from paraffin liquid. The structure properties were adjusted by a dosage of activating agents and carbonization temperature. The result with a 3:1 mass ratio of ZnCl2/PPy at 600 °C showed the highest micropore area and percentage of micropore volume of 1105 m2/g and 86.26%, respectively. In addition, the PPC surface was rich in functional groups and obtained a high N-doped content from 7.00 to 8.82%. The toluene adsorption behavior onto the PPC was comprehensively investigated including isotherms, kinetics, and thermodynamics. The adsorption isotherm accorded with the Freundlich model well, and the kinetic model was fitted more closely to the pseudo-second-order chemisorption. The thermodynamic research uncovered that the adsorption was spontaneous and an endothermic process in essence. The ZnCl2 activation mechanism is discussed based on TG/TGA curves and pore structure analysis at last. The devised way of synthesized microporous carbon is green and simple, which is suited to mass production for the adsorption of toluene from paraffin liquid and reducing environmental pollution.

Liquid paraffin oil is harmful to organisms as it contains noxious substances such as aromatic hydrocarbons. Since liquid paraffin oil is difficult to be decomposed in organisms, liquid paraffin oil will eventually reach the human body through the food chain. Besides, the presence of aromatic hydrocarbons in liquid paraffin oil also debases the downstream products. Therefore, it is of great practical value to remove aromatic hydrocarbons in liquid paraffin oil. In this study, pinecone-based activated carbon was prepared to adsorb naphthalene, which is a typical aromatic hydrocarbon in liquid paraffin oil. The prepared adsorbents were characterized by Scanning Electron Microscopy (SEM), N2 adsorption-desorption isotherms, X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). N2 adsorption-desorption isotherms manifested that the specific surface area (SSA) amplified with the KOH/precursor proportion. Although the highest SSA (1191 m2/g) was achieve in the adsorbent with an impregnation rate of 1:4 (KOH/precursor), the sample with an impregnation rate of 1:2 showed the largest adsorption capacity (435 mg/g) of naphthalene. This indicated that the SSA was not directly proportional to the adsorption capacity of naphthalene and the existence of mesoporous was also favorable for adsorption. The adsorption kinetic parameters were fitted with the pseudo-first-order, pseudo-second-order, and intra-particle diffusion models. The adsorption isotherms were fitted by Langmuir and Freundlich models. Finally, the KOH activation mechanism was also discussed.

In this study, 75% and 96% argon diluent conditions were selected to determine the ignition delay time of stoichiometric mixture of C2H4/O2/Ar within a range of pressures (1.3-3.0 atm) and temperatures (1092-1743 K). Results showed a logarithmic linear relationship of the ignition delay time with the reciprocal of temperatures. Under both two diluent conditions, ignition delay time decreased with increased temperature. By multiple linear regression analysis, the ignition delay correlation was deduced. According to this correlation, the calculated ignition delay time in 96% diluent was found to be nearly five times that in 75% diluent. To explain this discrepancy, the hard-sphere collision theory was adopted, and the collision numbers of ethylene to oxygen were calculated. The total collision numbers of ethylene to oxygen were 5.99×1030 s-1cm-3 in 75% diluent and 1.53×1029 s-1cm-3 in 96% diluent (about 40 times that in 75% diluent). According to the discrepancy between ignition delay time and collision numbers, viz. 5 times corresponds to 40 times, the steric factor can be estimated.

Nonmagnetic semiconductor based magnetoresistance (MR) devices combining high performance and low cost have attracted a lot of attention. However, it has been a great challenge to separate the interface MR from the bulk MR in the devices composed of Schottky heterojunctions. In this paper, the MR effect of a silicon-based Schottky heterojunction device had been studied, and its mechanisms were investigated by separating the interface MR effects from the bulk MR effects through combining two-probe and four-probe methods. We find that the bulk MR value is significantly smaller than the total MR value in the avalanche breakdown region in the temperature range of 150 K to 300 K, indicating that the total MR effect mainly originates from the interface MR effect. Theoretical analysis shows that the bulk MR effect is a normal one due to the existence of the Lorentz force on the carriers, and the interface MR effect relates to the suppression of the local plasmas by applying magnetic fields, where the local plasmas form due to the avalanche breakdown in the Ag/SiO2/p-Si Schottky heterojunctions. The total MR effect at room temperature can be further enhanced by reducing the distance between electrodes, and the total MR reaches about 1847% under a magnetic field of 1 T and the MR sensitivity is as large as 118.5 T−1 under 0.1 T.

A rapid, sensitive, reproducible, and inexpensive method of high-performance liquid chromatography with fluorescence detection after an anion-exchange solid-phase extraction cleanup step for the analysis of ochratoxin A (OTA) in Chinese wine was developed. The average recovery rate and the average RSD of recovery were 97.47% and about 4%. The relative standard deviations of both the interday and intraday precision were 6.7 and 12.6%, respectively. The limits of detection and quantitation were determined to be 0.01 and 0.03 μg/L, respectively. A total of 223 samples from the major wine-producing areas of China were analyzed for OTA. OTA was detected at levels of 0.01-0.98 μg/L. The mean was 0.15 μg/L. Then, participants as representative inhabitants were invited to answer the designed questionnaire about the quantity and frequency of wine consumption. All data were simulated by the point evaluation for the risk assessment of OTA contamination from wine. Those results indicated that daily intake (DI) of OTA for the average adult consumer varies between 0.86 and 1.08 ng/kg bw per week, which was lower than all the reference standards. However, the DI value (4.38-5.54 ng/kg bw per week) in the high percentile (97.5) was slightly above 5% PTWI (100 ng kg(-1) week(-1)) of the JECFA. In conclusion, OTA exposure from Chinese wine has no risk of harm. This research will provide the scientific basis for determining the maximum limit of OTA content in Chinese wine.

C15H24O3, monoclinic, P21 (no. 4), a = 6.83(1) Å, b = 9.29(1) Å, c = 12.81(2) Å, β = 103.29(2)°, V = 790.8 Å3, Z = 2, Rgt(F) = 0.0869, wRref(F2) = 0.2471, T = 296 K.

A modified form of Tung's integral equation allows the variance M 2p of the observed polymer chromatogram to be expanded as the sum of the main contribution due to molecular weight distribution plus the band spreading contribution μ2 (the variance of a single component chromatogram being eluted, at the same average elution volume) and a series of correction terms negligible for narrow molecular weight distribution. A model of the chromatographic separation taking into account hydrodynamical and diffusional spreading effects in each of the different columns in the apparatus leads to a Van Deemter's relationship relating μ2 to solvent flowrate. The coupling of the two above quoted relationships was used to exploit experimental measurements of M 2p for anionically polymerized polystyrene samples vs. solvent flowrate in a set of 3 μ-styragel R columns having nominal pores sizes 103, 104 and 105 A. These measurements, as well as previous work (where methods of treatment of data are discussed) were used to brin...