Fabrication and characterization of nylon 6/foliated graphite electrically conducting nanocomposite

In this study, the nylon 6/foliated graphite (FG) electrically conducting nanocomposites with a low percolation threshold of less than 0.75 vol % have been prepared via an in situ polymerization approach in the presence of FG nanosheet filler. Based on laser counting, scanning electron microscopy, transmission electron microscopy, and X‐ray diffraction characterization techniques, the structures and morphologies of the nanoscale filling particles and the resulting nanocomposites were examined. Using percolation theory, the conductivity behavior of the nanocomposite samples were modeled and analyzed. Through the use of mean‐field and excluded volume approaches, it was demonstrated that the experimentally observed percolation threshold values could be approximately estimated, and a correlation between the percolation threshold and the aspect ratio of FG particles could be quasi‐quantitatively established. Also, preliminary studies on the effects of FG nanosheets on the thermal properties of the host nylon 6 were performed. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2844–2856, 2004     

Non‐Pyrolytic,Large‐Scale Synthesis of Trichalcogenasumanene: A Two‐Step Approach

Trichalcogenasumanenes were synthesized on a multigram scale through a two‐step approach that takes advantage of non‐pyrolytic cyclization and solventless ring contraction. Solid‐state structure and photophysical investigations demonstrate that these compounds are promising candidates for electronic materials.     

An Adjustable pH‐Responsive Drug Delivery System Based on Self‐Assembly Polypeptide‐Modified Mesoporous Silica

In this study, an adjustable pH‐responsive drug delivery system using mesoporous silica nanoparticles (MSNs) as the host materials and the modified polypeptides as the nanovalves is reported. Since the polypeptide can self‐assemble via electrostatic interaction at pH 7.4 and be disassembled by pH changes, the modified poly(l ‐lysine) and poly(l ‐glutamate) are utilized for pore blocking and opening in the study. Poly(l ‐lysine)‐MSN (PLL‐MSN) and poly(l ‐glutamate)‐MSN (PLG‐MSN) are synthesized via the ring opening polymerization of N‐carboxyanhydrides onto the surface of mesoporous silica nanoparticles. The successful modification of the polypeptide on MSN is proved by Zeta potential change, X‐ray photoelectron spectroscopy (XPS), solid state NMR, and MALDI‐TOF MS. In vitro simulated dye release studies show that PLL‐MSN and PLG‐MSN can successfully load the dye molecules. The release study shows that the controlled release can be constructed at different pH by adjusting the ratio of PLL‐MSN to PLG‐MSN. Cellular uptake study indicates that the drug is detected in both cytoplasm and nucleus, especially in the nucleus. In vitro cytotoxicity assay indicates that DOX loaded mixture nanoparticles (ratio of PLL‐MSN to PLG‐MSN is 1:1) can be triggered for drug release in HeLa cells, resulting in 88% of cell killing.     

Study on a Multiplexer a 40 Gb/s OTDM System

In a 4?0Gb/s OTDM system (optical time-division-multiplication) system, multiplexing devices are key devices. The time interval of four channels of the 40Gb/s OTDM system is 25ps respectively. If the time intervals are no accurate, will induce the system performance to degeneration. In order to make out OTDM device and carry out a transmission experiment in a 40Gb/s OTDM system, a kind of OTDM device is researched. This scheme be used to fabricate multiplex device. Also the device have been used to a 40Gb/s OTDM system. Our experimental results shows that, the multiplex device based on the six 1 optical fiber couplers can be used to multiple at a time domain.That make four 10Gb/s optical signals multiple to 40Gb/s. The time interval error of each of channels is not bigger than 1ps, inserted loss is smaller than 2dB.     

Lightly doping Ca2+ in perovskite PrCoO3 for tailored spin states and electrical properties

A series of Pr(1-x)Ca(x)CoO(3) samples were prepared using a novel molten salt reaction that is convenient to obtain single phases avoiding aggregates compared to conventional solid state reactions. The formation reaction was monitored by X-ray diffraction combined with thermal analysis, and all samples were characterized by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and alternating current impedance. It is demonstrated that all Pr(1-x)Ca(x)CoO(3) samples crystallized in a pure orthorhombic perovskite structure. By increasing the doping level, the symmetry of the orthorhombic structure was enhanced, and is followed by an increase in the population of Co(3+) in the intermediate spin state. All samples exhibited typical semiconducting behavior, showing conductivities highly dependent on the Ca(2+) doping. The conduction for x = 0 shows a simple thermal activated process, which changed into a Mott's variable range hopping mechanism for x > 0. By increasing the Ca(2+) doping level, the relevant activation energy is decreased, while the density of the localized electronic state is increased.     

Ti-doped LiAlH4 for hydrogen storage: synthesis, catalyst loading and cycling performance

The direct synthesis of LiAlH(4) from commercially available LiH and Al powders in the presence of TiCl(3) and Me(2)O has been achieved for the first time. The effects of TiCl(3) loadings (Ti/Al = 0, 0.01, 0.05, 0.2, 0.5, 1.0 and 2.0%) and various other additives (TiCl(3)/Al(2)O(3), metallic Ti, Nb(2)O(5), and NbCl(5)) on the formation and stability of LiAlH(4) have been systematically investigated. The yield of LiAlH(4) initially increases, and then decreases, with increasing TiCl(3) loadings. LiH + Al → LiAlH(4) yields above 95% were obtained when the molar ratios of Ti/Al were 0.05 and 0.2%. In the presence of a very tiny amount of TiCl(3) (Ti/Al = 0.01%), LiAlH(4) is still generated, but the yield is lower. In the complete absence of TiCl(3), LiAlH(4) does not form. Addition of metallic Ti, Nb(2)O(5), and NbCl(5) to commercial LiH and Al does not result in the formation of LiAlH(4). Preliminary tests show that TiCl(3)-doped LiAlH(4) can be cycled, making it a suitable candidate for hydrogen storage.     

辣椒碱新同系物的合成、表征及辣构关系的初步探讨

合成了两种辣椒碱同系物的新成员:反-N-(4-羟基-3-甲氧基苄基)-8-甲基-4-壬烯酰胺和N-(4-羟基-3-甲氧基苄基)-3,7-二甲基-6-辛烯酰胺,并用元素分析,FT-IR,1H NMR,13C NMR等方法对其结构进行了表征,还用斯科维尔感官评定的方法对其辣度进行了测定,分别为1.2×107和3.0×106SHU.并将它们的结构和辣度与辣椒碱、降辣椒碱和高辣椒碱进行了对比,总结出影响辣椒碱同系物辣度的结构因子为脂酰基双键的位置、脂酰基主链的长度及支链.     

Fe3O4 nanoparticle loaded paclitaxel induce multiple myeloma apoptosis by cell cycle arrest and increase cleavage of caspases in vitro

We experimentally and theoretically characterize back-scattering and extinction of Ag nanoparticle (AgNP) arrays on both Si wafer substrates and optically-thick Ag substrates with and without organic poly(3-hexylthiophene):[6,6]-phenyl C61-butyric acid methyl ester (P3HT:PCBM) bulk-heterojunction thin film coatings. A strong red-shift in back-scattered light wavelength occurs from AgNP arrays on Si as a function of increasing mean nanoparticle diameter (ranging from 30 to 90 nm). Back-scattering from the AgNP array is notably quenched in the wavelength range of strong P3HT absorption when the organic layer is applied. However, back-scattering is enhanced to a degree relative to the uncoated AgNP array on Si at wavelengths greater than the absorption band edge of P3HT. For comparison, the optical properties of AgNPs on an optically-thick Ag substrate are reported with and without P3HT:PCBM thin film coatings. On the reflective Ag substrates, a significant enhancement (by a factor of 7.5) and red-shift of back-scattered light occurred upon coating of the AgNPs with the P3HT:PCBM layer. Additionally, red-edge extinction was enhanced in the P3HT:PCBM layer with the presence of the AgNPs compared to the planar case. Theoretical electromagnetic simulations were carried out to help validate and explain the scattering and extinction changes observed in experiment. Both increasing nanoparticle size and an increasing degree of contact with the Si substrate (i.e., effective index of the nanoparticle environment) are shown to play a role in increasing back- and forward-scattering intensity and wavelength, and in increasing absorption enhancements in both the organic and Si layers. AgNPs placed at the P3HT:PCBM/Si interface give rise to absorption increases in P3HT of up to 18 %, and only enhance Si absorption at wavelengths longer than the absorption band edge of P3HT (by almost 90 % in the 660–1,200 nm wavelength range). These results provide insight into how metal nanoparticles placed near an organic/inorganic interface can be employed for light management in tandem or hybrid organic/inorganic thin-film semiconductor configurations for solar energy harvesting applications or light detection applications.     

Synthesis of high-performance LiFePO4/C composite with a grape bunch structure through the hydrothermal method

The LiFePO₄/C composite with a grape bunch structure was synthesized through the hydrothermal method at 170 °C for 7 h and followed by being fired at 750 °C for 4 h. Commercial Li₂CO₃, (NH₄)₂Fe(SO₄)₂?·?6H₂O, and (NH₄)₂HPO₄ were used as raw materials. Glucose was used as in situ coating carbon source, and the hydroxylated MWCNTs were used as connecting carbon wires which could be embedded into the carbon coating to form a uniform grape bunch structure. The resultant samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), energy dispersive spectrometry (EDS), elementary analysis (EA), Raman spectroscopy, and electrochemical tests. The results show that the grape bunch structure with a low disordered/graphene (D/G) ratio was found to be well dispersed in the LiFePO₄/C composite, and a three-dimensional carbonaceous network was formed which could enhance the electronic conductivity of the LiFePO₄/C composite remarkably. The resultant LiFePO₄/C composite shows a high discharge capacity of 160.3 mAh g^?1 at 0.1 C and 110.9 mAh g^?1 even at 10 C, and the cycling capacity retention rate reaches 99.6 % over 60 cycles. Besides, it also exhibits high conductivity, good reversibility, and excellent stability in EIS and CV tests.     

Trade credit contract with limited liability in the supply chain with budget constraints

The paper investigates the impacts of trade credit (i.e., open account payment) and limited liability on the performance of a two-level supply chain with budget constraints. It shows that limited liability accounts for the reason why the retailer with a lower initial budget initiates a higher ordering level under trade credit contract. Furthermore, this paper finds that trade credit contract could create value in a supply chain with budget constraints, and partly coordinate the supply chain.