人生长激素和转移的人生长激素基因对去垂体鱼的生长代偿效应

通过显微注射技术,将小鼠重金属螯合蛋白(MT-1)基因启动顺序与人生长激素基因顺序的重组体pMThGH注入鲤鱼(Cyprinus carpio)的受精卵内,由此发育的转基因鱼及其后代F1和F2均显示出快速生长效应。去垂体后,转基因鲤鱼F2持续生长,而非转基因鲤鱼和鲫鱼(Carassius auratus)的生长停止。给去垂体的鲫鱼腹腔注射生物合成的人生长激素(hGH),可恢复其生长。实验结果表明,转基因鱼体内表达和体外生物合成的hGH均能代偿鲤鱼和鲫鱼的内源生长激素并刺激去垂体鱼的生长。

Gate commutated thyristor with voltage independent maximum controllable current

In this letter, we use a novel 3-D model, earlier calibrated with experimental results on standard gate commutated thyristors (GCTs), with the aim to explain the physics behind the high-power technology (HPT) GCT, to investigate what impact this design would have on 24 mm diameter GCTs, and to clarify the mechanisms that limit safe switching at different dc-link voltages. The 3-D simulation results show that the HPT design can increase the maximum controllable current in 24 mm diameter devices beyond the realm of GCT switching, known as the hard-drive limit. It is proposed that the maximum controllable current becomes independent of the dc-link voltage for the complete range of operating voltage. © 1980-2012 IEEE.

Compressive response of glass fiber composite sandwich structures

Sandwich panels with crushable foam cores have attracted significant interest for impulsive load mitigation. We describe a method for making a lightweight, energy absorbing, glass fiber composite sandwich structure and explore it is through thickness (out-of-plane) compressive response. The sandwich structure utilized corrugated composite cores constructed from delamination resistant 3D woven E-glass fiber textiles folded over triangular cross section prismatic closed cell, PVC foam inserts. The corrugated structure was stitched to 3D woven S2-glass fiber face sheets and infiltrated with a rubber toughened, impact resistant epoxy. The quasi-static compressive stress-strain response of the panels was experimentally investigated as a function of the strut width to length ratio and compared to micromechanical predictions. Slender struts failed by elastic (Euler) buckling which transitioned to plastic microbuckling as the strut aspect ratio increased. Good agreement was observed between experimental results and micromechanical predictions over the wide range of core densities investigated in the study.

转基因鱼模型的建立

本研究运用显微注射方法,把带有小鼠重金属螯合蛋白(MT-1)基因启动顺序与人生长激素基因顺序的重组DNA片段,注入鲤鱼、鲫鱼和泥鳅等的受精卵内,在由此发育的受体中,50％以上整合了外源基因,成为转基因鱼。其中约有一半左右的转基因个体具有表达外源基因、合成人生长激素的能力,并显示出不同程度的快速生长效应。转基因鱼已通过有性生殖将外源基因传递给子代,后者亦具有表达人生长激素的能力。至此,本研究首次建立了一个高效、简洁而且完整的转基因鱼模型,它为鱼类基因工程定向育种新技术奠定了实验基础。同时,本文还就鱼类基因转

Novel field emission from graphene sheets supported by CNTs arrays

A good quality graphene is transferred onto honeycomb-like CNTs arrays with inner supporting CNTs. The efficient field emission is demonstrated due to a high aspect ratio protrusions and graphene crack edges. A high efficient current density about 1.2 mA/cm2 at threshold electric field of 7.8 V/μm with a turn-on electric field of 1.8 V/μm at the current density of 10 μA/cm2 is observed due to high localized electric field. Stable field emission is tested in a vacuum chamber. The results are of significance to the development of Graphene based field emitters. © 2013 IEEE.

Novel nanostructured carbon nanotube electron sources

In this chapter, we present a review of our continuing efforts toward the development of discrete, low-dimensional nanostructured carbon-based electron emitters. Carbon nanotubes and nanofibers, herein referred to simply as CNTs, are one-dimensional carbon allotropes formed from cylindrically rolled and nested graphene sheets, have diameters between 1 and 500 nm and lengths of up to several millimeters, and are perfect candidates for field emission (FE) applications. By virtue of their extremely strong sp2 C-C bonding, intrinsic to the graphene hexagonal lattice, CNTs have demonstrated impressive chemical inertness, unprecedented thermal stabilities, significant resistance to electromigration, and exceptionally high axial current carrying capacities, even at elevated temperatures. These near ideal cold cathode electron emitters have incredibly high electric field enhancing aspect ratios combined with virtual point sources of the order of a few nanometers in size. The correct integration and judicious development of suitable FE platforms based on these extraordinary molecules is critical and will ultimately enable enhanced technologies. This chapter will review some of the more recent platforms, devices and structures developed by our group, as well as our contributions towards the development of industry-scalable technologies for ultra-high-resolution electron microscopy, portable x-ray sources, and flexible environmental lighting technologies. © 2012 by Pan Stanford Publishing Pte. Ltd. All rights reserved.

Growth kinetics and uniform scaling-up of graphene synthesis

Chemical vapor deposition on copper is the most widely used method to synthesize graphene at large scale. However, the clear understanding of the fundamental mechanisms that govern this synthesis is lacking. Using a vertical-flow, cold-wall reactor with short gas residence time we observe the early growths to study the kinetics of chemical vapor deposition of graphene on copper foils and demonstrate uniform synthesis at wafer scale. Our results indicate that the growth is limited by the catalytic dissociative dehydrogenation on the surface and copper sublimation hinders the graphene growth. We report an activation energy of 3.1 eV for ethylene-based graphene synthesis. © The Electrochemical Society.

All-chemical vapor deposited graphene/silicon nitride TFTs

All-chemical vapor deposited silicon nitride / monolayer graphene TFTs have been fabricated. Polychromatic Raman spectroscopy shows high quality monolayer graphene channels with uniform coverage and significant interfacial doping at the source-drain contacts. Nominal mobilities of approximately 1900 cm 2V-1s-1 have been measured opening up a potentially useful platform for analogue and RFR-based applications fabricated through allchemical vapor deposition processes. © The Electrochemical Society.

CNTs & graphene for field emission applications

This paper details the use of carbon nanotubes and graphene for key field emission applications. Herein we describe the growth of nanotubes and their optimization for use in electron microscopes, field emission displays and x-ray sources. We also present a novel edge-emitting graphene based structure for large area electron emission displays.

A highly conductive and transparent solution processed AZO/MWCNT nanocomposite

A solution processed aluminum-doped zinc oxide (AZO)/multi-walled carbon nanotube (MWCNT) nanocomposite thin film has been developed offering simultaneously high optical transparency and low electrical resistivity, with a conductivity figure of merit (σDC/σopt) of ~75-better than PEDOT:PSS and many graphene derivatives. The reduction in sheet resistance of thin films of pristine MWCNTs is attributed to an increase in the conduction pathways within the sol-gel derived AZO matrix and reduced inter-MWCNT contact resistance. Films have been extensively characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), X-ray diffractometry (XRD), photoluminescence (PL), and ultraviolet-visible (UV-vis) spectroscopy. © 2013 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Graphene SOI CMOS sensors for detection of PPB levels of NO2 in air

There is considerable demand for sensors that are capable of detecting ultra-low concentrations (sub-PPM) of toxic gases in air. Of particular interest are NO2 and CO that are exhaust products of internal combustion engines. Electrochemical (EC) sensors are widely used to detect these gases and offer the advantages of low power, good selectivity and temporal stability. However, EC sensors are large (1 cm3), hand-made and thus expensive ($25). Consequently, they are unsuitable for the low-cost automotive market that demands units for less than $10. One alternative technology is SnO2 or WO3 resistive gas sensors that are fabricated in volume today using screen-printed films on alumina substrates and operate at 400°C. Unfortunately, they suffer from several disadvantages: power consumption is high 200 mW; reproducibility of the sensing element is poor; and cross-sensitivity is high. © 2013 IEEE.

Fridericia liangi sp nov (Enchytraeidae, Oligochaeta) from Changbaishan Mountain, China

We describe one new enchytraeid species, Fridericia liangi sp. nov., from Mt. Changbaishan, Jilin Province, northeastern China. It was collected from soils at the foot of Changbaishan Mountain and is distinguished from all known congeners by the following combination of characters: 1) no lateral chaetae, only ventral chaetae throughout, 2) a maximum of four chaetae in ventral preclitellar bundles, 3) one chaeta in ventral postclitellar bundles, 4) dorsal pores from VII on, 5) esophageal appendages unbranched, 6) coelomocytes without refractile vesicles, 7) clitellum girdle shaped, well developed, 8) no subneural glands, and 9) spermathecae simple.