夯筑土遗址中基于PS-(F+C)浆液的木锚杆锚固性能

基于室内物理模型试验和原位锚固试验,对基于PS-(F+C)（高模数硅酸钾溶液-（粉煤灰+粉土））浆液的木锚杆锚固系统在夯土介质中进行了拉拔测试与杆体-浆体界面应变监测,研究了该锚固系统的锚固性能与破坏模式、杆体-浆体界面剪应力分布与传递特征。试验结果表明该锚固系统室内试验极限锚固力（24KN~33.49KN）远大于现场试验值（2.54KN~8KN）;锚固系统具有低弹性强塑性的特征,表现出极强的延性;在荷载进程中杆体-浆体界面的应力分布与传递特征具有多峰值分布、高值往往出现在锚固末端、压应力出现等特征,表明本锚固系统兼有拉力型和压力型全长黏结性锚固系统的特点。该系统适合于夯筑土遗址锚固,与遗址具有良好的物理力学兼容性。     

基于C8051F350三线制热电阻测温仪表的设计

详细阐述了基于C8051F350片上系统的热电阻测温仪表的工作原理与校准方案,并对测量误差进行了详细的分析,从整体上简化了传统测温仪表的电路结构,降低了仪表电路成本,同时也提高了的可靠性.     

关于电磁场对单摆运动控制的研究

电磁控制单摆运动系统主要由控制模块、驱动模块、输入模块和显示模块四部分组成。控制模块采用STM32F103单片机作为核心元件,根据检测到的摆杆运动方向和位置判断出摆杆当前运动状态,采用PID算法控制驱动模块中的直流电磁铁,给摆杆输入相应动能,实现对摆杆摆动角度和摆动周期的综合控制。驱动模块主要利用L298N芯片实现对线圈电流的大小和方向的设定,进而产生相应大小的吸引力和斥力。同时该系统的输入和显示模块采用了彩色TFT触摸屏。利用触摸屏制作出的输入及显示界面,不但功能丰富、操作简便而且具有良好的视觉效果。     

基于 MSP430单片机的智能照明控制系统的设计

为了解决生活中“长明灯”的浪费现象,设计了低功耗、低成本的智能照明系统。采用单片机MSP430 F149为主控制器,以热释电红外传感器来探测室内是否有人,并根据光照度传感器探测的环境亮度,来实时调节和控制室内LED的照明情况,最终达到智能照明以及节能的效果。     

Synthesis and characterization of triclinic structural LiVPO4F as possible 4.2 V cathode materials for lithium ion batteries

A potential 4.2 V cathode material LiVPO4F for lithium batteries was prepared by two-step reaction method based on a carbon-thermal reduction （CTR） process. Firstly, V2O5, NH4H2PO4 and acetylene black are reacted under an Ar atmosphere to yield VPO4. The transition-metal reduction is facilitated by the CTR based on C→CO transition. These CTR conditions favor stabilization of the vanadium as V^3＋ as well as leaving residual carbon, which is useful in the subsequent electrode processing. Secondly, VPO4 reacts with ElF to yield LiVPO4F product. The property of the LiVPO4F was investigated by X-ray diffractometry （XRD）, scanning electron microscopy （SEM） and electrochemical measurement. XRD studies show that LiVPO4F synthesized has triclinic structure（space group p I ）, isostructural with the naturally occurring mineral tavorite, EiFePO4-OH. SEM image exhibits that the particle size is about 2μm together with homogenous distribution. Electrochemical test shows that the initial discharge capacity of LiVPO4F powder is 119 mA·h/g at the rate of 0.2C with an average discharge voltage of 4.2V （vs Ei/Li^＋）, and the capacity retains 89 mA·h/g after 30 cycles.     

燃烧离子色谱法测定α-烯烃齐聚反应体系中催化剂BF3的含量

BF₃作为α-烯烃齐聚反应催化剂,其含量控制对催化反应的调控与产品质量的把控至关重要。通过建立样品前处理方法、优化仪器测试条件与标准溶液配制方法,建立利用燃烧离子色谱测定BF₃·醇催化的α-烯烃齐聚反应体系中F元素含量,进而计算出BF₃含量的方法,并考察了方法的重复性和准确性。结果表明：利用该方法可测定BF₃质量分数范围为2.68～53.50 g/kg的样品,前处理时适量的正丁醇和白油可有效稳定和稀释样品;测定稀释样品中F元素含量的标准曲线分为2段,线性范围分别为300～2000 mg/L和2000～3000 mg/L,线性相关系数R²分别为0.9992和0.9940;测定5次BF₃质量分数结果相对标准偏差均小于5%,方法加标回收率在95.0%～105.0%之间,方法检出限取决于前处理时的取样量,当取样量为5 g时,检出限为1 mg/kg。     

Self-assembly of telechelic polymers bearing adamantane groups via host-guest inclusion complexes with cyclodextrin polymer

Self-assembly and supramolecular inclusion complexations between telechelic polymers bearing one or double adamantane groups and linear poly(β-cyclodextrin) (P(β-CD)) were investigated in water. An adamantane (Ada) attached to poly (acrylic acid) (PAA) was prepared by reversible addition-fragmentation chain transfer polymerization using s-1-dodecyl-s″ -(α,α′-dimethyl-α″-acetic acid) trithio-carbonate functionalized Ada with tert-butyl acrylate, followed by functional modification. Additionally, two Ada groups capped triblock copolymer F127 were obtained via an esterification reaction. The dynamic light scattering, transmission electron microscope and ¹H 2D NOSEY NMR spectroscopy were conducted to characterize the self-assembly behaviors. With the inclusion complexation of Ada/CD in 1:1 M ratio in water, the spherical micelles were enlarged at 25°C than that of the adamantyl polymer precursors. Due to the PPO segment of Ada-F127-Ada, the micelles aggregation showed temperature dependence from 4 to 37°C for precursor and corresponding inclusion complexation; while in Ada-PAA/P(β-CD) system, the hydrodynamic diameters decreased with pH decreasing.     

Competent F18 bioglass-Biosilicate® bone graft scaffold substitutes

Biosilicate® glass-ceramic (BioS) offers an attractive choice for the manufacturing of scaffolds because of their high bioactivity, non-toxicity, bactericidal activity and biodegradability. Despite these positive properties, Biosilicate® scaffolds that have been developed so far show low fracture strength, limiting their clinical application. For this reason, our aim was to increase their strength through vacuum infiltration of F18 bioactive glass. First, we calculated the maximum attainable theoretical compressive strength of a scaffold using the Ryshkewitch and Ashby-Gibson models. We show that for a total porosity of 80 %, σ₀ = 250 MPa, and n = 5 the compressive strength estimated by both models is approximately 4.5 MPa. Afterward, the Biosilicate scaffolds were prepared using the foam replica technique and recoated several times with a F18 glass slurry to eliminate surface defects. Scanning Electron Microscopy examination showed that the F18 indeed helped to remove surface defects and partially infiltrated the hollow struts, significantly increasing their mechanical integrity. The F18-BioS scaffolds exhibited a total porosity of 82 %, an average cell size of 525 μm, and compressive strength of 3.3 ± 0.3 MPa, which is close to the predicted value and significantly higher than those of sole BioS scaffolds of a similar structure (< 0.1 MPa). These values are within the range of commercial scaffolds based on Hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP), having a considerable advantage of being more osteoinductive, angiogenic, and highly bactericidal. The F18-BioS scaffolds developed in this work thus have high potential for odontology or craniofacial surgeries that do not involve high load–bearing conditions.     

Nanocrystallization of Pd74Si18Au8 metallic glass

The crystallization process of Pd₇₄Si₁₈Au₈ amorphous alloy has been investigated by transmission electron microscopy, small angle X-ray scattering and three-dimensional atom probe techniques. Although literature suggests that the alloy decomposes into two glassy phases prior to the crystallization, we found that the crystallization occurs directly from a single amorphous phase by the primary crystallization of fcc Pd–Au solid solution, followed by the polymorphous crystallization of the remaining amorphous phase to a Pd₃Si phase.     

F/B复相钢JB800的焊接冷裂纹敏感性

采用斜Y坡口对接裂纹试验对F／B复相钢板JB800进行了抗冷裂试验，对不同预测止裂温度的碳当量公式进行了对比。结果表明,钢材的碳含量低时，可以在较高的碳当量条件下，具有较低的冷裂纹敏感性。对F／B复相钢采用CET公式预测止裂温度较为准确。同时采用计算机测定了焊接热循环，根据t100预测不同板厚的焊接止裂温度。