Synthesis of PNIPAAm-g-P4VP Microgel as Draw Agent in Forward Osmosis by RAFT Polymerization and Reverse Suspension Polymerization to Improve Water Flux

Microgels have unique and versatile properties allowing their use in forward osmosis areas as a draw agent. In this contribution, poly(4-vinylpyridine) (P4VP) was synthesized via RAFT polymerization and then grafted to a poly(N-Isopropylacrylamide) (PNIPAAm) crosslinking network by reverse suspension polymerization. P4VP was successfully obtained by the quasiliving polymerization with the result of nuclear magnetic resonance and gel permeation chromatography characterization. The particle size and particle size distribution of the PNIPAAm-g-P4VP microgels containing 0, 5, 10, 15 and 20 wt% P4VP were measured by means of a laser particle size analyzer. It was found that all the microgels were of micrometer scale and the particle size was increased with the P4VP load. Inter/intra-molecular-specific interactions, i.e., hydrogen bond interactions were then investigated by Fourier infrared spectroscopy. In addition, the water flux measurements showed that all the PNIPAAm-g-P4VP microgels can draw water more effectively than a blank PNIPAAm microgel. For the copolymer microgel incorporating 20 wt% P4VP, the water flux was measured to be 7.48 L∙m⁻²∙h⁻¹.     

Flavonoids from Lycium barbarum Leaves Exhibit Anti-Aging Effects through the Redox-Modulation

Lycium barbarum leaves are a kind of vegetable, and modern nutrition studies have found that they have an anti-aging function. Our study aims to investigate the anti-aging effects of Lycium barbarum leaf flavonoid (LBLF) extracts and its underlying molecular mechanism. LBLFs were purified using D101 and polyamide resin, characterized by ultraperformance liquid chromatography coupled with mass spectrometry, and administered to hydrogen peroxide (H₂O₂)-treated human umbilical vein endothelial cells (HUVECs) and Caenorhabditis elegans. Appropriate enrichment conditions were optimized through dynamic adsorption and desorption experiments, the content of flavonoids reached 909.84 mg/g, rutin and kaempferol being the main ones. LBLFs attenuated H₂O₂-induced HUVEC apoptosis, decreased reactive oxygen species and malondialdehyde production levels, increased superoxide dismutase, glutathione peroxidase and catalase activities. Furthermore, pre-treatment with LBLF increased mRNA expression of erythropoietin (EPO) and heme oxygenase-1 (HO-1) via the mitogen-activated protein kinase (MAPK) signaling pathway in HUVECs. Compared with 100 µM rutin monomer, LBLF prolonged the lifespan of Caenorhabditis elegans, enhanced their mobility in middle life stages and upregulated expression of sod-2, gcs-1 and skn-1 genes, which indicated that the anti-aging effects of LBLF were due to its redox-modulation.     

颜色视觉匹配中显示器颜色色差阈值的评价

为了对阴极射线管(Cathode ray tube,CRT)显示器颜色恰可辨别的小色差阈值进行评价,在中性灰背景下,用编制的颜色匹配程序,在CRT显示器上随机产生颜色,分别调节程序中R、G、B通道的值,使匹配色与随机色达到视觉上的一致,进行颜色视觉匹配实验,测量CRT显示器上随机色和匹配色的L*a*b*值.用不同的色差公式对实验数据分别从明度、色调、饱和度进行比较分析,色差公式评价小色差的性能是CIEDE2000优于CMC(2∶1)和CIEL*a*b*.在a*b*图上绘制实验颜色恰可辨别图.不同色差公式计算的CRT显示器恰可辨别小色差阈值不同.     

双偏振结构保偏光纤偏振器的研制

提出了保偏光纤偏振器的一种串联结构,即双偏振结构,报道了研制的结果。并通过对单偏振结构和双偏振结构器件测试结果的比较,得出双偏振结构的保偏光纤偏振器可使器件达到高消光比,并且有稳定的温度特性。     

Perturbative Power Counting,Lowest-Index Operators and Their Renormalization in Standard Model Effective Field Theory

We study two aspects of higher dimensional operators in standard model effective field theory.We first introduce a perturbative power counting rule for the entries in the anomalous dimension matrix of operators with equal mass dimension.The power counting is determined by the number of loops and the difference of the indices of the two operators involved,which in turn is defined by assuming that all terms in the standard model Lagrangian have an equal perturbative power.Then we show that the operators with the lowest index are unique at each mass dimension d,i.e.,(H~?H)~(d/2)for even d≥4,and(L~TεH)C(L~TεH)~T(H~?H)~((d-5)/2)for odd d≥5.Here H,L are the Higgs and lepton doublet,andε,C the antisymmetric matrix of rank two and the charge conjugation matrix,respectively.The renormalization group running of these operators can be studied separately from other operators of equal mass dimension at the leading order in power counting.We compute their anomalous dimensions at one loop for general d and find that they are enhanced quadratically in d due to combinatorics.We also make connections with classification of operators in terms of their holomorphic and anti-holomorphic weights.     

Discrete Boltzmann Method with Maxwell-Type Boundary Condition for Slip Flow

The rarefied effect of gas flow in microchannel is significant and cannot be well described by traditional hydrodynamic models. It has been known that discrete Boltzmann model(DBM) has the potential to investigate flows in a relatively wider range of Knudsen number because of its intrinsic kinetic nature inherited from Boltzmann equation.It is crucial to have a proper kinetic boundary condition for DBM to capture the velocity slip and the flow characteristics in the Knudsen layer. In this paper, we present a DBM combined with Maxwell-type boundary condition model for slip flow. The tangential momentum accommodation coefficient is introduced to implement a gas-surface interaction model.Both the velocity slip and the Knudsen layer under various Knudsen numbers and accommodation coefficients can be well described. Two kinds of slip flows, including Couette flow and Poiseuille flow, are simulated to verify the model.To dynamically compare results from different models, the relation between the definition of Knudsen number in hard sphere model and that in BGK model is clarified.     

干涉型光纤传感器相位生成载波解调方法改进与研究

提出了基于干涉型光纤传感器的相位生成载波解调方法（PGC）的改进方法,通过算法上的改进和增加抗混叠滤波器,有效地改善了解调结果,并大大降低了系统的采样频率,结论对设计干涉型光纤传感器解调系统有重要的参考意义     

Investigation of the Interaction Between N-benzyl Piperidones and Bovine Serum Albumin by Spectroscopic Approaches

Fluorescence and ultraviolet spectroscopies were applied to investigate the interaction between five N-benzyl piperidones (NBP) and bovine serum albumin (BSA) under imitated physiological conditions. The experimental results show that these NBPs have a static fluorescence quenching effect on the endogenous fluorescence of BSA at the temperatures 302 and 310?K. According to the fluorescence quenching theory, the Stern?CVolmer quenching constant (K _SV), the binding constant (K _a), and the number of binding sites (n) were obtained. Also, the effect of substituents on the binding capacity between NBP and BSA is in the order: C₆H₅?<?4-CH₃OC₆H₄?<?4-CH₃C₆H₄?<?2,4-Cl₂C₆H₃?<?4-ClC₆H₄. The corresponding thermodynamic parameters (??G, ??H, and ??S) were obtained at two different temperatures and indicate that hydrogen bonding and van der Waals forces play main roles in stabilizing the BSA?CNBP complex. The binding distance between the tryptophan residue in BSA and NBP was found to be much <7?nm based on the F?rster theory of non-radiation energy transfer. The effect of NBP on the conformation of BSA was analyzed as well by synchronous fluorescence spectroscopy.     

New correlation equations for predicting filter coefficient ratio of submicron particles at high ionic strength when the diffusiophoretic effect is considered

New correlation equations for the deep-bed filtration, including the term of diffusiophoresis, in addition to the Derjaguin and Landau, Verwey and Overbeek interactions, the Brownian diffusion and the interception, for predicting the initial collection efficiency under the favorable deposition condition and the filter coefficient ratio under the unfavorable deposition condition are derived by using the Brownian dynamics-simulation method. These new correlation equations for predicting the filter coefficient ratio are able to describe previous experimental results especially well for those submicron particles that are at high ionic strength.     

Syntheses and Crystal Structures of Two One-dimensional Cobalt(Ⅱ) Compounds with the Flexible Dipyridyl Ligan

Two one-dimensional cobalt(Ⅱ) compounds {[Co(Hbpma)(H2O)4 ] 2 ·3SO 4 ·4.5H2O} n1 and {[Co(Hbpma)(NCS) 3 (H2O)]·2.85H2O}n2 (bpma = N,N -bis(3-pyridylmethyl)amine) have been synthesized and structurally characterized by single-crystal X-ray diffraction. Complex 1 crystallizes in triclinic, space group P1 with a = 15.8780(5), b = 16.2187(5), c = 16.4858(5) , α = 91.0420(10), β = 94.5190(10), γ = 101.4360(10)°, V = 4145.7(2) 3 , C 24 H 53 Co 2 N 6 O 24.50 S 3 , M r = 1031.76, Z = 4, D c = 1.653 g/cm 3 , μ(MoKα) = 1.046 mm -1 , F(000) = 2148, S = 1.017, the final R = 0.0269 and wR = 0.0644 for 13032 observed reflections (I > 2σ(I)). For complex 2, it belongs to triclinic, space group P1 with a = 9.3761(11), b = 10.5814(13), c = 11.2972(14) , α = 85.472(2), β = 88.058(2), γ = 76.203(2)°, V = 1085.0(2) 3 , C 15 H 21.70 CoN 6 O 3.85 S 3 , M r = 502.79, Z = 2, D c = 1.539 g/cm 3 , μ(MoKα) = 1.112 mm -1 , F(000) = 519, S = 1.070, the final R = 0.0358 and wR = 0.0899 for 3466 observed reflections (I > 2σ(I)). Two complexes 1 and 2 are both found to be one-dimensional coordination polymers bridged by the protonated bpma ligands, which are assembled into three-dimensional supramolecular structures through the hydrogen bonding interactions and π-π packing interactions.