碳改性对SAPO-5结构和吸附CH4性能的影响

以三乙胺为结构导向剂,在高温水热条件下合成了SAPO-5分子筛材料,并将之分别置于空气和氮气氛下823K焙烧。用XRD、RAMAN、TG及水和甲烷吸附实验考察了氮气氛下分子筛表面碳改性前后对材料结构稳定性及吸水和甲烷性能的影响。结果表明：碳改性后SAPO-5在孔道内生成了纳米碳材料,晶体衍射强度减弱,结构稳定性提高。与SAPO-5样品相比,碳改性后SAPO-5吸水量略微降低：CH4常压吸附量从0．138％提高到0．253％。     

基于CH395的跨平台远程文件管理系统

基于FTP应用协议,通过CH395实现跨平台远程文件管理系统。CH563作为主控制芯片,负责处理所有的事务;CH395作为以太网协议栈芯片,提供以太网数据传输通道。该系统硬件简单,遵循熟悉的文件操作方式,很好地实现了文件共享和数据管理。     

NIOS-Ⅱ处理器的大容量数据采集存储系统设计

以NIOS-Ⅱ处理器为核心,构建一个SOPC系统,控制CH376文件管理芯片,将采集的数据以文件形式写入U盘中,以满足现场大容量数据的快速采样存储的需要。由于FPGA具有输入输出引脚多、运行速度快和可编程的特点,只要软件稍作修改,即可将数据存入SD卡中。经过软硬件的综合测试,能成功实现系统各项功能。     

基于C8051f040与传感器阵列的瓦斯浓度实时监测系统

利用高性能、低功耗C8051f040单片机设计一种新型信号采集、处理电路,通过多通道模拟多路开关CD4067实现传感器阵列中的多个传感器分时工作,并使用上位机显示程序实现瓦斯浓度的实时监测.实验表明：该系统可以实现多个传感器分时工作,并具有较高的精度,在保证每个传感器标定周期为2星期的条件下,8个传感器组成的传感器阵列的标定周期达到16个星期.     

单片机在温湿度测量系统中的应用

从硬件和软件两个方面介绍以MCS-51单片机为核心的温湿度测量系统的组成,重点给出了硬件和软件系统,该系统由传感器、下位机、接口组成,具有多点测量、数据掉电保护和与PC机通讯等多种功能.用户可通过键盘设置需要的温、湿度值以及报警的上下限值,并通过数码管即时显示.该测量系统具有成本较低、使用简单、工作可靠等特点,具有一定应用前景.     

Bond strength of steel bars embedded in high-performance fiber-reinforced cementitious composite before and after exposure to elevated temperatures

Interfacial bond strengths of steel reinforcing bars embedded in a high-performance fiber-reinforced cementitious composite (HPFRCC) are investigated in this paper. Out of 303 pullout specimens, 48 HPFRCC and 3 normal concrete specimens were tested without any heat treatment, and 240 HPFRCC and 12 normal concrete specimens were heated at 200, 400, 600, or 800 °C in a furnace for 2 h prior to testing. The effects of bar shape, diameter, and length embedded in HPFRCC on the bond strength of HPFRCC specimens were investigated. The bond strength decreased with the heating temperature and with the size and embedded length of steel bars. It was reduced further when the heated specimens were cooled in water instead of air. It was disaggregated into chemical adhesion and mechanical interlock from a comparative study of plain and deformed bars. The mechanical properties and microstructures of HPFRCC specimens before and after heat treatment were compared to understand the mechanisms of interfacial bonding degradation due to heat treatment.     

Peptide‐Passivated Lead Halide Perovskite Nanocrystals Based on Synergistic Effect between Amino and Carboxylic Functional Groups

A new strategy has been developed using peptides with amino and carboxylic functional groups as passivating ligands to produce methyl ammonium lead bromide (CH₃NH₃PbBr₃) perovskite nanocrystals (PNCs) with excellent optical properties. The well‐passivated PNCs can only be obtained when both amino and carboxylic groups are involved, and this is attributed to the protonation reaction between ? NH₂ and ? COOH that is essential for successful passivation of the PNCs. To better understand this synergistic effect, peptides with different lengths have been studied and compared. Due to the polar nature of peptides, peptide‐passivated PNCs (denoted as PNCs_peptide) aggregate and precipitate from nonpolar toluene solvent, resulting in a high product yield (≈44%). Furthermore, the size of PNCs_peptide can be varied from ≈3.9 to 8.6 nm by adjusting the concentration of the peptide, resulting in tunable optical properties due to the quantum confinement effect. In addition, CsPbBr₃ PNCs are also synthesized with peptides as capping ligands, further demonstrating the generality and versatility of this strategy, which is important for generating high quality PNCs for photonics applications including light‐emitting diodes, optical sensing, and imaging.     

低浓度甲烷流向变换催化燃烧反应研究

将制备的整体式催化剂应用于小型流向变换催化燃烧反应系统上,在甲烷初始浓度为0.2%,气量为30 L·min-1,换向半周期为10 min的工况条件下考察了不同预热温度对甲烷催化燃烧活性的影响以及反应系统床层轴向温度分布情况。结果表明,随着预热温度升高,甲烷催化燃烧活性呈现升高的趋势,同时,在催化剂中添加助剂元素Pt可以提高催化剂催化活性;催化剂的预热温度对反应器床层温度分布影响较大,特别是反应系统的催化段。     

Isomerization and anti-Markovnikov arylation of olefin catalyzed by an iridium complex

An iridium acetylacetonato complex, a catalyst for anti-Markovnikov arylation of olefins, was found to work as a catalyst for olefin isomerization. 2-butene was obtained with 0.55 cis/trans ratio in isomerization of 1-butene. Moreover, in 1-hexene/benzene solution, isomerization and arylation of 1-hexene were simultaneously catalyzed by the iridium complex.     

Combined CO/CH4 oxidation tests over Pd/Co3O4 monolithic catalyst: Effects of high reaction temperature and SO2 exposure on the deactivation process

CO and CH₄ combined oxidation tests were performed over a Pd (70 g/ft³)/Co₃O₄ monolithic catalyst in conditions of GHSV = 100,000 h⁻¹ and feed composition close to that of emission from bi-fuel vehicles. The effect of SO₂ (5 ppm) on CO and CH₄ oxidation activity under lean condition (λ = 2) was investigated. The presence of sulphur strongly deactivated the catalyst towards methane oxidation, while the poisoning effect was less drastic in the oxidation of CO. Saturation of the Pd/Co₃O₄ catalytic sites via chemisorbed SO₃ and/or sulphates occurred upon exposure to SO₂. A treatment of regeneration to remove sulphate species was attempted by performing a heating/cooling cycle up to 900 °C in oxidizing atmosphere. Decomposition of PdO and Co₃O₄ phases at high temperature, above 750 °C, was observed. Moreover, sintering of Pd⁰ and PdO particles along with of CoO crystallites takes place.