利用火焰枪对超弹性形状记忆合金进行局部热处理的初步研究

构建了基于火焰枪的局部热处理系统,对消除超弹性镍钛形状记忆合金(SMA)弹簧端部目标部位的超弹性开展了初步实验研究,并结合温度与硬度测试,探讨了热处理温度、保温时间、加热方式对超弹性消除效果、处理部位颜色的影响。结果表明,该系统可在770℃以上、极短的保温时间内有效消除镍钛SMA弹簧目标部位的超弹性而主体几乎不受影响。热处理温度是目标部位超弹性能否消除的决定性因素,而保温时间的影响不大。灼烧方式比热传导方式更易引起目标部位的颜色变化。     

岩石热破裂与渗透性相关规律的试验研究

岩石热破裂是一类极为普遍的自然与工程现象。利用"600℃20MN伺服控制高温高压岩体三轴试验机系统"进行砂岩和花岗岩在常温至600℃范围内的声发射特征和渗透性演化规律的试验研究,揭示岩石的热破裂规律与渗透性的相关特征,其结果如下:(1)花岗岩和砂岩受热作用,在常温到600℃区间,其热破裂存在一个清晰的门槛值。从声发射特征来看,永城细砂岩与鲁灰花岗岩的热破裂门槛值分别为170℃和65℃。(2)岩石热破裂门槛值之后,随温度升高,热破裂呈间断性与多期性变化特征,从常温到600℃,既非单调增加,也非单调减少,一般存在2个以上的峰值区间。(3)随着温度的升高,伴随岩石峰值破裂段的发生,岩石的渗透率也呈现出同步的多个峰值段,伴随着声发射平静期滞后出现渗透率相对降低区,但渗透率仍然维持在一个较高水平,而且随着声发射剧烈期出现次数的增加,渗透率愈来愈大。     

Ag-polyaniline nanocomposite cladded planar optical waveguide based humidity sensor

The paper reports synthesis of Ag-polyaniline nanocomposite and its evaluation as an active optical cladding on a planar optical waveguide (POW) as a humidity sensor with variable concentration of the composite. The nanocomposite is dispersed in acetonitrile, and spin coated on the planar waveguide to form a clad. The system shows response to humidity, when tested in the range of 20–92% relative humidity (RH). A prism film coupling is used to characterize the cladded waveguide. The maximum sensitivity is seen for 47% concentration of the nanocomposite in acetonitrile. The response and recovery of the sensor are 8 and 55 s respectively. The low hysteresis is exhibited by the sensor. The sensor has repeatability and reproducibility. Material characterization is done using Scanning Electron Micrograph (SEM), X-Ray Diffraction (XRD), Ultraviolet Spectroscopy (UV) and Fourier Transform Infrared Spectroscopy (FTIR).     

Systematic evaluation on the effectiveness of conjugated linoleic acid in human health

The term CLA (conjugated linoleic acid) corresponds to a mixture of positional and geometric isomers of linoleic acid. Two of these isomers (9c, 11t and 10t, 12c) have biological activity. The milk and dairy products are the most abundant source of conjugated linoleic acid, which refers to a group of positional and geometric isomers of CLA (CLA 18:2 cis-9, cis-12). The following research aims to approach aspects regarding the CLA, as well as its relationship with diseases. Conjugated linoleic acids have been studied for their beneficial effects in the prevention and treatment of many diseases, including obesity, cancer, diabetes, and cardiovascular diseases. Scientific information put together the physiological properties of CLA, which serves as inputs to claim their potential as functional ingredients to be used in the prevention and control of several chronic metabolic disorders.     

Genetically Modifiable Flagella as Templates for Silica Fibers: From Hybrid Nanotubes to 1D Periodic Nanohole Arrays

Bacterial flagellum is a protein nanotube that is helically self‐assembled from thousands of a protein subunit called flagellin. The solvent‐exposed domain of each flagellin on the flagella is genetically modifiable, in that a foreign peptide can be genetically inserted into this domain, leading to the high‐density display of this foreign peptide on the surface of flagella. In this work, wild‐type and genetically engineered flagella (inner diameter of ～2 nm and outer diameter of ～14 nm) detached from the surface of Salmonella bacterial cells are used as templates to site‐specifically form silica sheaths on the flagellar surface, resulting in the formation of double‐layered silica/flagella nanotubes. The flagella templates inside the silica/flagella nanotubes can be removed to obtain silica nanotubes by calcining the nanotubes at high temperature (550°C). Further calcination of the silica nanotubes at a higher temperature (800 °C) leads to the formation of a periodic nanohole array along the silica fibers with a center‐to‐center nanohole spacing of ～79 nm. It is demonstrated that the double‐layered silica‐flagella nanotubes can be used for selective CdTe quantum dot uptake into the inner channels or selective Au nanoparticle coating on the outer wall of the nanotubes due to the different chemistry between inner flagellum core (protein) and outer silica wall of the nanotubes. It is also found that flagella displaying different peptides result in different morphologies of the silica nanotubes. This work suggests that the monodisperse diameter and genetically tunable surface chemistry of the flagella can be exploited for the fabrication of silica nanotubes with uniform diameter and controllable morphologies as well as silica nanofibers decorated with periodic nanohole arrays.     

High Level Oscillations With Narrow Linewidth in Magnetic Nano-Contact Spin Torque Oscillator With Synthetic AF Spin-Valve Structure

We investigated the current induced magnetization dynamics, so called spin torque oscillation, in magnetic nano-contact MR element with a synthetic antiferromagnetic type spin-valve structure under high in-plane applied magnetic field of 0.9-1 kOe. Very high level oscillation of 18 nVHz^-1/2 with narrow FWHM of 12 MHz was observed in the condition of negative applied current where electron-spin is injected from free layer to reference one. Applied current dependency on an oscillation frequency is a blueshift with good linearlity, and same dependency on level and FWHM is almost constant in the range of -10 to -14 mA, while applied field dependency on frequency shows redshift with two different slopes, -2.5 MHz/Oe in less than 1 kOe and -8.7 MHz/Oe in more than 1 kOe which field is smaller than the spin-flop field for the synthetic antiferromagnet, besides very clear and reasonable peak and bottom for oscillation level and FWHM are observed, respectively. It is thought that these magnetization dynamics are originated from synthetic antiferromagnet.     

多协议标签交换的合并组播研究

本文首先引入一种新的基于MPLS的合并组播树,然后主要讨论了采用MPLS合并组播树在减少MPLS容错组播的备份树与标签消耗方面的高效性,最后的模拟分析表明在组播中采用MPLS合并组播树是有效的。     

Resistance of chylomicron and VLDL remnants to post-heparin lipolysis in ApoE-deficient mice: the role of apoE in lipoprotein lipase-mediated lipolysis in vivo and in vitro

The interaction of lipoprotein lipase (LPL) with triglyceride-rich lipoproteins is governed by a number of factors, such as apolipoprotein (apo) C-II. The role of apoE in lipolysis is controversial. We made the unexpected observation that apoE-deficient mice were resistant to heparin-induced lipolysis; this study aims at examining the underlying mechanism for this observation. Compared to wild-type mice, apoE-deficient mice had significantly higher very low density lipoprotein (VLDL) and chylomicron remnant (VLDL/CMR) concentrations and moderately lower lipase activity (15.5 +/- 1.3 mU/ml vs. 22.9 +/- 2.5 mU/ml). Unlike in wild-type mice where the injection of heparin reduced total plasma triglycerides by 50% and VLDL/CMR triglycerides by over 95%, the injection of heparin into apoE-deficient mice did not significantly affect plasma lipids. Similarly, in vitro, purified human LPL (hLPL) almost completely hydrolyzed VLDL/CMR isolated from wild-type mice, but had no effect on VLDL/CMR from apoE-deficient mice. However, when the amount of apoE-deficient VLDL/CMR was reduced to an equivalent level as in wild-type mice, LPL hydrolyzed 94% of VLDL/CMR triglycerides. In order to increase the ratio of LPL to VLDL/CMR in vivo, we injected an adenovirus containing the human LPL cDNA into apoE-deficient mice, which produced marked liver-specific overexpression of LPL and significant reduction of VLDL/CMR (93%) and total plasma triglyceride concentrations (87%). Thus, apoE is not required for LPL activity in vivo or in vitro. Under certain pathological conditions, such as severe hyperlipidemia, the LPL pathway may be saturated and efficient lipolysis can proceed only if the ratio of substrate particles to LPL is adjusted to a more normal range.     

Robustness of general decay stability of nonlinear neutral stochastic functional differential equations with infinite delay

This paper establishes the existence-and-uniqueness theorem of neutral stochastic functional differential equations with infinite delay and examines the almost sure stability of this solution with general decay rate. This result may be used to examine almost sure robust stability. To illustrate our idea more carefully, we carefully discuss a scalar stochastic integro-differential equation with neutral type and its asymptotic stability, including the exponential stability and the polynomial stability.     

不同温度条件下孔隙压力对长石细砂岩渗透率影响试验研究

为探讨温度和孔隙压力对岩石渗透率的影响规律,采用中国矿业大学211工程建设项目"20 MN伺服控制高温高压岩体三轴试验机",在不同温度和恒定压力条件下,对长石细砂岩进行大试样的实时渗透率研究,试样为圆柱体,外观尺寸为φ200 mm×400 mm.加温试验发现,长石细砂岩渗透率存在门槛值温度,当温度达到门槛值后,其渗透率出现大幅度增加,与室温状态相比,渗透率增加65倍.在长石细砂岩热破裂的门槛值温度区域,长石细砂岩渗透率同时具有孔隙压力门槛值,其渗透率在孔隙压力门槛值发生剧烈变化,大幅度增加;继续增加温度脱离温度门槛值后,孔隙压力对于渗透率的影响随之减弱.