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Palladium nanorods (PdNRs) into mesoporous channels of SBA-15 nanocatalyst (PdNRs/SBA-15) were synthesized by a green and surfactant-free ultrasonic method without any surfactants and complex chemical modification and chemical method in absence of ultrasound, respectively. The PdNRs/SBA-15 catalysts were characterized by XRD, TEM, XPS, N2 absorption-desorption and FT-IR analysis. The results showed that PdNRs with 15.96 ± 3.89 nm long and 5.69 nm wide were highly dispersed into mesoporous channels exploiting the confine effect of SBA-15 pore channel, while reunited PdNPs were distributed on the outside surface of SBA-15 in PdNPS/SBA-15 prepared by chemical method. The in-situ ultrasonic reduction of PdNRs/SBA-15 by the reductive radical (induced by ultrasonic process) was good for higher dispersion of Pd species and the formation of Pd species inside the mesoporous channel of SBA-15 without any structure-directing agents or surfactants. The yield of Suzuki coupling reaction between 4-bromotoluene and phenylboronic acid catalyzed by PdNRs (5)/SBA-15 reached 96.4%, which was much higher than that of PdNPs(5)/SBA-15 prepared without ultrasound (76.3%). PdNRs (5)/SBA-15 could be reused up to five times without a significant activity loss due to the strong chemical interaction and the unblocked channel.

A green process for the synthesis of supported Pd nanoparticles (NPs) using poplar leaf extract (PLE) as a reducing agent and the extracted residue of poplar leaf (RPL) as a carrier is reported. The Pd/RPL nanocomposites were characterized by XRD, TEM, SEM, EDS, XPS, FTIR, and ICP-AES. The spherical Pd NPs had a mean particle size of 3.1 nm and were evenly distributed on the RPL surface. More importantly, the Pd/RPL nanocomposites were used as a heterogeneous catalyst, which presented superior catalytic activity for the Suzuki coupling reaction. In addition, only a slight loss in the catalytic activity was observed after six recycles.

Background: Cyclocarya paliurus (Batal.) Iljinskaja is a common endemic tree species. The leaves of C. paliurus are used as a Chinese medicine and the main active components are polysaccharides. However, the temporal pattern of polysaccharide synthesis at different leaf developmental stages has not been reported to date. Results: With the development of leaves, the content of polysaccharides increased first and the highest content was found at the F3 stage (the third larger full expanded leaf). A total of 499710194 clean reads were obtained using C. paliurus genomic data and were assembled into 296593 unigenes. Among 4708 identified DEGs, 429 DEGs were up-regulated and 451 DEGs were down-regulated from F1 stage (the smallest full expanded leaf) to F2 stage (the second larger full expanded leaf), 630 DEGs were up-regulated and 60 DEGs were down-regulated from F2 stage to F3 stage, and 1833 up-regulated and 1816 down-regulated DEGs from F3 stage to F4 stage. Forty DEGs associated with GT belong to 13 GT families. Among them, only one gene was down-regulated from F1 stage to F2 stage, two genes were down-regulated from F2 to F3 stages, and 23 genes were down-regulated and 15 genes were up-regulated from F3 stage to F4 stage, respectively. A significant correlation exists between the five unigenes and the polysaccharide content. UDP-glucose 4-epimerase gene was significantly positively correlated with the polysaccharide content. A pathway map for the biosynthesis of C. paliurus polysaccharide was proposed. Among 150 transcription factors identified from DEGs, the majority was members of the AP2/ERF family (21, 14%), followed by the C2H2 family (14, 9.33%), the MYB family (12, 8%), the C2C2-GATA family (10, 6.67%), the GRAS family (9, 6%), and the zf-HD family (7, 4.67%). Conclusions: These results identified genes involved in the biosynthesis of Cyclocarya paliurus polysaccharides during different leaf developmental stages and provided evidence for the change of polysaccharide content during the development of C. paliurus leaves. Possible synthetic pathways and related transcription factors were suggested. This study provides information for the screening of polysaccharide biosynthesis related genes and elucidates the mechanism underlying polysaccharide biosynthesis in C. paliurus.

Layered double hydroxide (LDH)-supported Pd nanocatalysts (Pd/LDH-OH) were prepared by ultrasonic-assisted reduction at 30 °C using an ultrasonic bath at a frequency of 25 kHz and an input power of 400 W for 30 min without the addition of any stabilizing reagent or chemical reductant, using LDH with a layered structure and interparticle mesoporosity as the reductant and carrier. This kind of pore structure allows ultrasound waves to spread inside the pore and make ultrasound directly act on the surface hydroxyl groups of LDH, producing highly reductive free radicals ( H). The reductive free radicals rapidly reduced Pd2+ to Pd0, forming ultrafine Pd nanoparticles (PdNPs) with a particle size distribution of 1.85 nm–3.45 nm and an average particle size of 2.52 nm. The surface hydroxyl groups were converted to exposed oxygen groups after dissociation of hydrogen radicals, which is beneficial for anchoring and dispersing the resultant PdNPs. The resultant PdNPs were uniformly dispersed on the surface of the LDH carrier. The yield of the Suzuki coupling reaction between 4-bromotoluene and phenylboronic acid catalyzed by Pd/LDH-OH at 60 °C was 95.49% for 5 min and the TOF was 190.98 min−1. After repeated for 5 times, the yield was maintained at 84.59%. The prepared Pd/LDH-OH nanocatalyst and the catalytic system are useful for Suzuki-Miyaura coupling reactions of N- and S-heterocyclic substrates. This provides an efficient and green approach for the preparation of supported nanopalladium catalysts.

The Cu2+doped porous CdIn2S4 microspheres (Cu@CdIn2S4) with better photocatalytic performance were prepared by sodium dodecyl sulphate (SDS)-assisted hydrothermal technology. The Cu@CdIn2S4 were characterized by SEM, XPS, XRD and DRS. The effects of Cu2+ doping amount on the morphology, structure and photocatalytic hydrogen production performance of CdIn2S4 were studied. The porous Cu@CdIn2S4 microspheres were flower shape of a average diameter of 3-5 μm and their maximum absorption edge was up to 700 nm. The Cu2+ doping was good for the improvement of photocatalytic performance. Cu@CdIn2S4 with 0.3wt% Cu2+doping amount possessed the highest hydrogen production rate of 1248.1 μmol/(h·g), much more than that of pure CdIn2S4.

The bio‐synthesis of palladium nanocubes (PdNCs) was realised using pine needle extract as the reducing agent and cetyl trimethyl ammonium bromide as the capping agent. As an eco‐friendly and readily available biomass, pine needle extract avoided the use of highly polluting chemical reducing agents. The growth process of PdNCs was analysed using ultraviolet–vis and Fourier transform infrared spectroscopy. Flavonoids, esters, terpenoids and polyhydric alcohols, which contain reductive groups, were mainly responsible for the transition of Pd(2+) ions to PdNCs. The morphology and structure of PdNCs were characterised using transmission electron microscopy (TEM), high‐resolution TEM, selected area electron diffraction and X‐ray diffraction. It was indicated that the as‐prepared PdNCs displayed a relatively high purity and good crystallinity with a face‐centred cubic structure and exhibited sizes ranging from 6.11 to 29.51 nm with an average particle size of 11.18 nm. In the methanol electro‐oxidation reaction, the PdNCs enclosed by {100} facets exhibited superior electro‐catalytic activity to commercial Pd/C, which was rarely reported in other bio‐synthesis processes for Pd catalysts. Meanwhile, the PdNCs showed excellent anti‐poisoning ability and long‐term stability. This study reveals the possibility of preparing shape‐controlled PdNCs with a specific structure and excellent electro‐catalytic activity.

This paper proposes an analytical model for the asymmetric double-gate (ADG) TFET operation. Two-dimensional Poisson equation is solved based on the depletion approximation [1,2]. The two-dimensional potential function is given by appropriate boundary conditions. Internal electric field is calculated from the potential model and tunnel current is numerically calculated using the Kane’s tunnel current generation model [3,4]. We used the commercial TCAD simulator in order to examine the analytical model [5]. Schematic of ADG-TFET device structure is shown in Fig. 1. It is assumed that p-type source and n-type drain regions are highly doped. Channel region is a p-type with the doping level of Na . tox denotes the gate oxide thickness and tsi denotes the semiconductor film thickness. Hereafter, we call the top gate “front gate” and the bottom gate “back gate”. Potential profile of the channel region is derived from the following two-dimensional Poisson equation based on the depletion approximation. Equation (1) where q denotes the elemental charge and εsi denotes the permittivity of semiconductor. Here, we assume the following potential function with the cubic function of coordinate y [1]. Equation (2) where four factors a(x), b(x), c(x), and d(x) are functions of coordinate x. We introduce the following boundary conditions for the potential in solving eq. (1). Equation (3) where ψf(x) and ψb(x) stand for front and back surface potentials at y=0 and y=t si, respectively. Vfg,fb and Vbg,fb are the front-gate and the back-gate flat-band voltages, respectively. Vfg and Vbg are the front- and back-gate voltages, respectively. εox is the permittivity of gate insulator. Drain current of ADG TFET is numerically calculated by integrating carriers tunneling from the valence band of the source region to the conduction band of the channel region. We can calculate the drain current (IDS ) using the carrier generation rate (G) due to the band-to-band tunnel process. Equation (4) where we use the Kane’s model for the carrier generation rate (G) [3,4]. Equation (5) where |E| (=(Ex 2+Ey 2)1/2 ) is the electric field strength, A and B are constants given by Equation (Si) Equation (Ge) We perform the TCAD simulation [5] in order to examine the validity of the analytical model. In device simulations for Si-based TFETs, we assume the gate material with the work function of 4.1 eV for the front- and the back-gate electrodes. Figure 2 shows the calculated potential profiles at y=0nm, 2.5nm, and 5.0nm for tsi =10nm. Using the potential function revealed in Fig. 2, local electric field values are calculated along with the x direction and the y direction separately. The potential function analytically given and resulting electric fields successfully reproduced those given by TCAD simulations (not shown here). We found a slight difference of potential profile near the surface around the source junction for a relatively low-doping source region because of the depletion in the source region [6]. We also calculated drain current characteristics. Figure 3 demonstrates ID-Vfg characteristics for tsi =10nm and 20nm, where the condition of Lg >2ts is satisfied. In Fig. 5, the model basically reproduces the TCAD result. On the other hand, the model doesn’t well reproduce TCAD-based ID-Vgf characteristics for tsi =30nm and 100nm (not shown here), where Lg tsi . This difference stems from the linear approximation of the in-depth electric field in the model. As the condition of Lg >2tsi is important in the future, this is not a crucial issue of the model. In addition, we confirmed the model proposed here is available for Ge-based TFET (not shown here). References [1] J.-W. Han, C.-J. Kim, and Y.-K. Choi, “Universal potential model in tied and separated double gate mosfets with consideration of symmetric and asymmetric structure,” IEEE Trans. Electron Devices, Vol. 55, pp. 1472-1479, 2008. [2] K. Suzuki and T. Sugii, “Analytical model for n+ -p+ double-gate SOI MOSFETs,” IEEE Trans. Electron Devices, Vol. 42, pp. 1940-1948, 1995. [3] E. O. Kane, “Zener tunneling in semiconductors,” J. Phys. Chem. Solids, Vol. 12, pp. 181-188, 1960. [4] E. O. Kane, “Theory of tunneling,” J. Appl. Phys, Vol. 32, pp. 83-91, 1961. [5] Sentaurus TCAD Manual ver.G-2012.06. [6] F. Villani, E. Gnani, A. Gnani, S. Reggiani, and G. Baccarani, “A quasi 2D semianalytical model for the potential profile in hetero and homojunction tunnel FETs”, Tech. Dig., 44th ESSDERC (Venice, 2014), pp. 262-265. Figure 1

Intumescent flame retardant thermoplastic polyolefin (TPO) composites were prepared to study the relationships between their structure of charred layer (including of the multicellular intumescent layer and the charry layer) and flame retardant properties. They were characterized using the LOI and UL-94 test, which indicated that the best fire retardant behavior (V-0 rating and LOI reach to 28.1%) was obtained at the formulation of TPO/ammonium dihydrogen phosphate/starch (100/60/20). Thermal gravimetric analysis demonstrated that the presence of ammonium dihydrogen phosphate/starch promoted the esterification and carbonization process in lower temperature range while enhancing the thermal stability of intumescent flame retardant TPO in high-temperature range. Scanning electron microscope and optical microscope were shown that, with combustion time prolonged, the intumescent layers obtained greater number of cells, and the charry layer became more compact while the size of the carbon granules became smaller on the surface. Introduction of starch had an obvious effect on the structure of the intumescent and charry layers. The charry layer of the composites with the content of 20 phr starch was more compact and uniform than that of the composites with 50 phr. The weight ratio of ammonium dihydrogen phosphate to starch in the intumescent flame retardant was fixed as 3 : 1 which cooperated with each other well to promote a compact charry layer and to obtain the better flame retardancy performance. Therefore, the better the charred layers produced, and the better flame retardant properties they obtained. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

This paper presents a 2-D potential model for the asymmetric double-gate tunnel FET (ADG-TFET) that well considers the source-channel junction depletion region. The model derives a closed and analytical form derived from the 2D Poisson equation by using the conformal mapping technique. Potential function and electric field function are given by appropriate boundary conditions. We use a commercial TCAD simulator to verify the model.

A novel coordination polymer, {[Eu2(L)3(CH3OH)(H2O)]·(CH3OH)(H2O)}n ( 1 ), has been synthesized by solvothermal reaction of Eu(NO3)3·6H2O and 9,9-diethylfluorene-2,7-dicarboxylic acid in a mixture solution of CH3OH and H2O. Single crystal X-ray structural analysis reveals that complex 1 crystallizes in an orthorhombic, space group P2(1)2(1)2(1), holding the unusual (2,3,8)-connected 3D topological network. Thermogravimetric analysis shows remarkable thermal stability of the structural framework of compound 1 , the photoluminescence properties are also discussed.

A green method for the synthesis of supported Pd nanoparticles (NPs) using pine needle extract as the reducing agent and the extracted residue of pine needle (RPN) as the carrier is described. The Pd/RPN nanocomposites were characterized using Fourier transform infrared, UV–visible, inductively coupled plasma atomic emission and X-ray photoelectron spectroscopies, transmission electron microscopy and X-ray diffraction. The spherical Pd NPs had a mean particle size of 3.25 nm and were evenly distributed on the RPN surface. More importantly, the Pd/RPN nanocomposite, as a heterogeneous catalyst, presented superior catalytic activity for the Suzuki coupling reaction. The yield of the reaction of 4-bromotoluene with phenylboronic acid catalyzed by Pd0.03/RPN reached 98% with low Pd loading (0.1 mmol%) at room temperature for 30 min. In addition, the catalyst could be easily separated by centrifugation and reused at least six times without significant loss of activity.

A series of CdxIn2S4-Zn1-xIn2S4 composite photocatalysts has been synthesized by hydrothermal method. The physical and photophysical properties of the CdxIn2S4-Zn1-xIn2S4 photocatalysts were characterized by X-ray diffraction, UV-Vis diffuse reflectance spectrum, X-ray photoelectron spectroscopy and scanning electron microscopy. CdxIn2S4-Zn1-xIn2S4 could form composite semiconductors with cubic spinel phase in agreement with CdIn2S4. The absorption edges of CdxIn2S4-Zn1-xIn2S4 were red-shifted and the band gaps energy gradually reduced with the increasing of x value in CdxIn2S4-Zn1-xIn2S4. CdxIn2S4-Zn1-xIn2S4 series photocatalysts were used in the photodecomposition of H2S to H2. The results indicated that the photocatalyst of Cd0.3In2S4-Zn0.7In2S4 exhibited the highest photocatalytic activity with the rate of H2 evolution to be 590 imol/(h•g) under visible light irradiation.