无线传感器网络中带粒子群优化的分簇节点睡眠调度算法

为延长无线传感器网络的生命周期,提高节点能量利用率,将分簇算法与睡眠调度算法相结合,提出一种无线传感器网络中带粒子群优化的分簇节点睡眠调度算法.该算法采用二进制编码机制,引入遗传算法的变异和交叉算子,同时考虑网络覆盖保持和能量消耗减少优化目标,构造一个相应的离散粒子群优化方法.仿真实验结果表明,文中算法能较好地减少能耗和保持网络覆盖,有效延长网络的生命周期.     

Suksdorfin Promotes Adipocyte Differentiation and Improves Abnormalities in Glucose Metabolism via PPARγ Activation

Although the Apiaceae herb family has been traditionally used for the management of type 2 diabetes, its molecular mechanism has not been clarified. Coumarin derivatives, which are abundant in plants of the Apiaceae family, were evaluated for their effects on adipogenesis. We found that suksdorfin significantly promoted adipocyte differentiation and enhanced production of adiponectin, an anti-diabetic adipokine. We also demonstrated that suksdorfin activates peroxisome proliferator-activated receptor gamma (PPARγ), a master regulator of adipogenesis. Furthermore, we showed metabolic disorders in obese diabetic KK-A^y mice were attenuated by suksdorfin feeding. Suksdorfin intake induced adipocyte miniaturization and increased expression levels of PPARγ target genes related to adipocyte differentiation. These results indicated that suksdorfin induces adipogenesis in white adipose tissue (WAT) via the activation of PPARγ, leading to improvement of obesity-induced metabolic disorders. Therefore, suksdorfin-mediated amelioration of WAT dysfunctions might be responsible for the anti-diabetic effects of traditional herbal medicine therapy with Apiaceae.     

Preparation, characterization, and properties of new crosslinked proton-conducting membranes with polyoxyalkylene moieties

A new class of crosslinked proton-conducting membranes (CPMs) with polyoxyalkylene moieties was designed and prepared based on poly(styrene-co-maleic anhydride) modified with 2-aminoethanesulfonic acid sodium salt (AESA-Na) and polyoxyalkylenediamines (PEGDAs). The number density of the pendant of sulfonate group was controlled by the ratio of AESA-Na to PEGDA. The resulted membranes possess good mechanical strength and excellent flexibility. The structural characterizations of these membranes were confirmed by FT-IR and solid-state ¹³C NMR spectra. All these membranes exhibit a wholly amorphous morphology, and show a one-step weight loss from 350 °C, indicating their good thermal stability. The CPM sample with 1.25 mequiv SO₃H per gram reaches the proton conductivity of 0.21 S cm⁻¹ at 30 °C and 0.49 S cm⁻¹ at 95 °C, respectively. Moreover, these protonated membranes show adequate oxidative stability in Fenton's reagent at 30 °C.     

悬浮区域熔炼法制备Ce1-xPrxB6单晶体及其热发射性能研究

以CeB₆和PrB₆粉末为原料, 采用放电等离子烧结结合悬浮区域熔炼法成功制备了晶体质量良好的多元稀土六硼化物Ce_1-xPr_xB₆(x=0.1、0.2、0.4)单晶体, 并系统研究了该系列单晶体(100)晶面热电子发射性能。结果表明: Ce_0.8Pr_0.2B₆单晶(100)晶面具有最好的热发射性能, 在1873 K, 最大电流发射密度达到66.07 A/cm², 比CeB₆单晶的电流发射密度提高约20%。此外, Ce_0.9Pr_0.1B₆、Ce_0.6Pr_0.4B₆单晶(100)晶面的热发射电流密度分别为65.81 A/cm²和65.31 A/cm²。Ce_0.8Pr_0.2B₆单晶(100)晶面的逸出功最低, 为2.61 eV, 其它单晶(100)晶面的逸出功在2.64~2.753 eV范围内。因此, Ce_1-xPr_xB₆多元稀土六硼化物单晶具有良好的发射性能和低的逸出功, 作为热阴极材料有很好的应用前景。     

4-Hydroxyderricin,as a PPARγ Agonist,Promotes Adipogenesis,Adiponectin Secretion,and Glucose Uptake in 3T3-L1 Cells

Adipocyte differentiation plays a pivotal role in maintaining the production of small‐size adipocytes with insulin sensitivity, and impaired adipogenesis is implicated in insulin resistance. 4‐Hydroxyderricin (4‐HD), a phytochemical component of Angelica keiskei, possesses diverse biological properties such as anti‐inflammatory, antidiabetic, and antitumor. In the present study, we investigated the effects of 4‐HD on adipocyte differentiation. 4‐HD promoted lipid accumulation in 3T3‐L1 cells, upregulated both peroxisome proliferator‐activated receptor (PPAR)‐γ mRNA and protein expression, and acted as a ligand for PPARγ in the luciferase assay. Moreover, 4‐HD increased the mRNA and protein expression levels of adiponectin. Additionally, it promoted insulin‐dependent glucose uptake into 3T3‐L1 adipocytes and increased Akt phosphorylation and glucose transporter (GLUT) 4 mRNA expression. In summary, these findings suggest that 4‐HD, which promoted adipogenesis and insulin sensitivity in 3T3‐L1 cells, might be a phytochemical with potent insulin‐sensitizing effects.     

棉花裸苗移栽机苗夹有限元分析

用ANSYS软件对棉花裸苗移栽机苗夹中的橡胶夹进行有限元分析,得到了橡胶夹只需4.7N就可以将棉苗夹住进行送苗及投苗,且不会造成伤苗的结果。根据分析结果可对橡胶夹施加力的位置、大小进行调整,对防止伤苗起到十分重要的作用。     

Inorganic-organic hybrid polymer electrolyte based on polysiloxane/poly(maleic imide-co-styrene) network

Covalently cross-linked nonfluorinated hydrocarbon ionomers are synthesized by introducing sulfonate groups and a siloxane cross-linker through thermally and chemically stable imide bonding on poly(styrene-co-maleic anhydride). The three-dimensional polysiloxane framework, which does not only act as a robust scaffold but also provide sites for the hydrogen bonding with water, contribute to the increase in bound water degree, higher proton conductivity at lower ion exchange capacity, and greatly decreased methanol permeability. The spherical-shaped ionic clusters produce a comparable proton conductivity (10⁻¹ S cm⁻¹ above 60 °C) to Nafion-117. The conductivity of the hybrid ionomer does not decrease to gain its selectivity, but instead increased. Methanol permeability is ∼70% lower than that of Nafion-117, but has a higher water uptake and IEC. The membrane with IEC values of 1.1 mequiv. g⁻¹ exhibits a constant conductivity for 200 h in hydrolytic stability test, and produce a power density 20% higher than Nafion-117 in single DMFC operation.     

Alignment under Magnetic Field of Mixed Fe2O3/SiO2 Colloidal Mesoporous Particles Induced by Shape Anisotropy

When using the bottom‐up approach with anisotropic building‐blocks, an important goal is to find simple methods to elaborate nanocomposite materials with a truly macroscopic anisotropy. Here, micrometer size colloidal mesoporous particles with a highly anisotropic rod‐like shape (aspect ratio ≈ 10) have been fabricated from silica (SiO₂) and iron oxide (Fe₂O₃). When dispersed in a solvent, these particles can be easily oriented using a magnetic field (≈200 mT). A macroscopic orientation of the particles is achieved, with their long axis parallel to the field, due to the shape anisotropy of the magnetic component of the particles. The iron oxide nanocrystals are confined inside the porosity and they form columns in the nanochannels. Two different polymorphs of Fe₂O₃ iron oxide have been stabilized, the superparamagnetic γ‐phase and the rarest multiferroic ε‐phase. The phase transformation between these two polymorphs occurs around 900 °C. Because growth occurs under confinement, a preferred crystallographic orientation of iron oxide is obtained, and structural relationships between the two polymorphs are revealed. These findings open completely new possibilities for the design of macroscopically oriented mesoporous nanocomposites, using such strongly anisotropic Fe₂O₃/silica particles. Moreover, in the case of the ε‐phase, nanocomposites with original anisotropic magnetic properties are in view.     

Formation of mesomorphic domains associated with dimer aggregates of phenyl rings in cold crystallization of poly(trimethylene terephthalate)

During the cold crystallization of poly(trimethylene terephthalate), PTT, multistage preordering activities associated with hierarchically structural evolution and origin of mesomorphic domains were investigated with time-resolved Fourier transform infrared (FTIR), photoluminescence (PL) and dielectric spectra (DS), and simultaneous small- and wide-angle X-ray scattering (SAXS/WAXS). The observed fluorescent emission at 390 nm and an absorption band at 874 cm⁻¹ associated with the CH out-of-plane bending mode of the phenyl rings indicate that the ground-state dimers resulting from the phenyl rings of PTT chains via π–π interactions are formed in supercooled amorphous liquids. The time dependences of the increase of the fluorescent intensities, the wavenumber shift from 874 to 872 cm⁻¹, the conformational transformation of the trimethylene glycol units from trans to gauche, the dynamic α-to-α′ transition of the dielectric loss and the structural parameters reveal that the dimer aggregation accompanying a locally nematic-like orientation induced large phase-separated mesomorphic domains (over several tens of nanometers); nucleations of nanograin type (over several nm) subsequently formed within the mesomorphic domains after the conformational transformation form trans to gauche for the cold crystallization at 50 °C. Herein, we propose a preordering mechanism of cold crystallization in which the π–π interactions among the dimers serve as ordering bonding forces to drive intermolecular cooperativity before intramolecular changes of conformation, and the dimer aggregation triggers the phase-separated mesomorphic domains before the growth of crystalline nanograins (non-lamellar crystals). As distinct from the hierarchical structure of nanograins within mesomorphic domains, the formation of lamellar crystallites within spherulites without undergoing the dimer aggregation were observed form the melt crystallization at 200 °C.