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151.
A. Proctor C. Adhikari G. D. Blyholder 《Journal of the American Oil Chemists' Society》1996,73(6):693-698
The structures of and lipid complexes with two commercial silica hydrogels (Trisyl and Sorbsil 40), which contain about 60%
moisture, were examined by diffuse reflectance Fourier transform infrared spectroscopy. The spectra suggested that Trisyl
contained less moisture than Sorbsil 40. However, the silanol groups of Sorbsil 40 were more active in adsorbing oleic acid,
triglyceride, and phosphatidylcholine (PC) from hexane than those of Trisyl. Both adsorbents strongly bound PC through the
PC carbonyl and phosphate groups. Lipid adsorption from hexane solution by Trisyl depended solely on trapped moisture, while
Sorbsil 40 used moisture and silanol groups on the silica surface. Spectra of triglyceride-silica hydrogel complexes, obtained
24 and 72 h after obtaining the initial spectra, showed that Sorbsil 40 adsorption was by Van der Waals forces, but the triglyceride
reoriented over time with an increase in hydrogen bonding. In contrast, Trisyl initially adosorbed triglyceride by hydrogen
bonding which was stable for at least 72 h. 相似文献
152.
153.
在同成分铌酸锂晶体中掺入0.03?2O3和0.1%MnO2(质量分数),分别掺入0,1%,3%,4.5%,6%的MgO(摩尔分数),用提拉法生长了一系列Mg:Mn:Fe:LiNbO3晶体.检测了Mg:Mn:Fe:LiNbO3晶体的红外光谱和抗光损伤能力.掺0,1%,3%,4.5%Mg的Mg:Mn:Fe:LiNbO3晶体的OH-红外振动峰位于3484cm-1,而掺6%Mg的Mg:Mn:Fe:LiNbO3晶体红外振动峰移到3 535gm-1.采用波长为632nm的He-Ne激光器作为光源,通过二波耦合方法测试晶体的全息存储性能.结果表明:Mg:Mn:Fe:LiNbO3晶体的写入时间和动态范围随掺镁量的增加而显著减小,而光折变灵敏度略有上升,抗光损伤性能增强,其中掺镁量为3%Mg:Mn:Fe:LiNbO3晶体更适合作为全息存储介质. 相似文献
154.
The interphase between a polyimide and a metal substrate was modeled by depositing phthalic anhydride (PA) onto a silver substrate pretreated with meta-aminothiophenol (m-ATP) and then curing in a mixture of acetic anhydride and pyridine or triethylamine. Surface-enhanced Raman scattering (SERS) and reflection-absorption infrared spectroscopy (RAIR) were used to determine the molecular structure of the interphase. It was found that m-ATP was adsorbed dissociatively onto silver substrates through the thiol groups. The tilt angle for m-ATP molecules adsorbed on silver substrates was determined using RAIR to be approximately 39°. However, there was no preferred rotational angle of the adsorbed APDS molecules about the molecular axes. When PA was deposited onto m-ATP pretreated silver substrates, anhydride groups of PA reacted with amino groups of m-ATP to form amic acids. When PA/m-ATP/Ag samples were chemically cured in acetic anhydride and pyridine or triethylamine, isoimide was the predominant product regardless of the use of pyridine or triethylamine as catalyst. These results were different from those obtained from PA/APDS/Au systems in which imide was the major product in the presence of triethylamine. These differences in the relative composition of cured products between two model systems were explained by the effect of substituents attached to APDS and m-ATP benzene rings. 相似文献
155.
A. Proctor C. Adhikari G. D. Blyholder 《Journal of the American Oil Chemists' Society》1995,72(3):331-335
Fourier transform infrared spectroscopy was used to investigate the adsorption of oleic acid (OA) onto dry rice hull ash (RHA)
silica. Adsorption partially occurred by surface hydrogen bonding of the carboxylic acid. There was also formation of carboxylate
ions by reaction of OA with residual potassium oxide. These ions were strongly bound by the ash. Isopropanol inhibited OA
adsorption by H-bonding and encouraged desorption of H-bonded OA, but without itself being significantly bound. RHA with 40%
moisture also adsorbed a small amount of OA by H-bonding and reacted with OA to form and adsorb carboxylate ions. 相似文献
156.
为了能在人口集中的公共场所快速、准确测量大批量人群体温,系统采用RE200B红外传感器作为温度采集器件,以STC89C52为核心,DS18B20传感器采集环境温度作为补偿温度,设计了一种电子红外测温仪.系统主要包括硬件和软件两大部分,红外信号经过光学系统聚焦在RE200B热释电探测器上并转变为相应的电信号,此信号经过放大、A/D转换,再送到单片机中进行数据的处理、补偿,最后送到液晶显示结果.软件采用C语言来编写.经实验测试:设计红外体温仪平均相对误差小于0.3%,符合系统设计的预期要求. 相似文献
157.
本文阐述了红外通讯的原理,介绍了一种基于51单片机的红外通讯实现方法,包括硬件电路和C程序设计,程序通用性好,易于移植于其它控制器.通过实验测试,实现了数据可靠发送和接收,表明了此方法的有效性. 相似文献
158.
Blends of sulfonated phenylated polytriphenylene oxide and poly(methyl methacrylate‐co‐4‐vinyl pyridine) were examined by dynamic mechanical, Fourier transform infrared, and NMR techniques. A high degree of miscibility was evident from a single drop in a plot of the storage modulus versus the temperature. The presence of ionic moieties due to proton transfer from sulfonic acid to 4‐vinyl pyridine was confirmed by both NMR and IR spectroscopy studies. The coils were found to be close to one another in dimethyl sulfoxide‐d6 because the aromatic shielding effect of the phenyl rings of the phenylated polytriphenylene oxide units was observed from the upfield shift of most of the protons of poly(methyl methacrylate) in the NMR spectrum. However, the absence of cross peaks in the nuclear Overhauser and exchange spectroscopy experiments suggested that the intermolecular distance between the chains had to be larger than 4 Å. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 728–733, 2003 相似文献
159.
何乃味 《单片机与嵌入式系统应用》2014,(5):66-69
介绍一种以低功耗单片机ATmega8L为控制核心,以RDA5807P芯片作为FM接收器的调频收音机。该收音机通过单片机ATmega8L的I2 C总线接口读写RDA5807P收音模块的数据,用按键及红外遥控器进行搜台、音量调节等操作。用LCD显示接收频道的频率,当前音量大小等信息。设计中给出了实现FM调频收音机的硬件电路、读/写RDA5807P收音模块及红外遥控解码程序的思路。经多次比对测试,该收音机可以清晰、稳定地收听省府及本地发射的所有调频电台。 相似文献
160.
Rheo-optical Fourier-transform infrared (FTIR) spectroscopy is based on the simultaneous acquisition of stress-strain data and FTIR spectra on-line to the mechanical treatment of polymers and is frequently applied for the characterization of transient structural changes during deformation and stress-relaxation. In the present communication, this technique has been employed in order to investigate the distribution of molecular orientation and its relaxation in uniaxially drawn solution-cast films of semicrystalline partial miscible blends of poly(butylene terephthalate) (PBT) with polycarbonate (PC) containing 10, 30 and 50 wt% PC. The uniaxial deformation of these blend films having a PBT-crystallinity degree ranging from 31 to 12%, in unstretched blends, leads to a appreciable high segmental orientation for the crystalline PBT due to a structural transformation from lamellae to microfibrils. The formation of this fibrillar structure is attributed to non-reversibility of an extended phase with all-trans conformational sequence of the aliphatic segments of PBT, occurring during elongation. The rate of relaxation of this conformational transition, however, increases with increasing amorphous content in the blends. Also it is observed that even with increasing amorphous content in the PBT/PC blends the crystalline PBT shows significant orientation. In such cases, apart from the few lamellae which transform to microfibrils, it is suggested that a stress induced transformation of PBT chains in amorphous PBT-component to irreversible all-trans extended crystalline form also contributes to PBT crystalline orientation. In contrast with this high crystalline orientation, the amorphous PBT located in the interlamellar regions inside the PBT-spherulites show a lower orientation in blends as compared in pure PBT.On the other hand, an overall segmental orientation of PC chains in blends is of lower order which is attributed mainly to low stretching temperature compared to Tg of pure PC. The results are discussed in terms of the resulting spherulitic morphology and the temporary network formed by the elongated PBT and PC chains inside the interlamellar regions, in blends. 相似文献