Synthesis and Characterization of Phosphonates from Methyl Linoleate and Vegetable Oils

Phosphonates were synthesized on a medium scale (~200 g) from three lipids—methyl linoleate (MeLin), high‐oleic sunflower oil (HOSO) and soybean oil (SBO), and three dialkyl phosphites—methyl, ethyl and n‐butyl, using a radical initiator. A staged addition of the lipid and the initiator was used to achieve good yields. Good results were observed with MeLin (94–99% conversions of the double bonds, as determined by NMR, and 83–99% isolated yields) and HOSO (99–100% NMR conversions, 87–96% isolated yields) using tert‐butyl perbenzoate as the initiator. With SBO, benzoyl peroxide was used as the initiator, due to its capability to generate radicals at a higher rate at slightly lower temperatures, and thus to shorten the reaction time. Conversions of 91–93% (by NMR) and isolated yields of 80–94% were achieved. The progress of the reaction was monitored with GC–MS. The products were characterized using ¹H, ¹³C and ³¹P NMR, IR and gel permeation chromatography. A prolonged reaction led to some transesterification between the carboxylic and phosphite ester groups. Conditions favoring higher reaction rates led to the formation of more oligomers and benzoate fatty ester byproducts. The benzoate fatty ester byproducts were formed by the attack of a benzoate radical on a double bond. The more double bonds that were present per lipid molecule, the more oligomers were formed: MeLin 2–8%, HOSO 3–9% and SBO 8–29%.     

天绘一号卫星高分辨、多光谱相机与三线阵正视相机夹角在轨标定方法研究

通过对天绘一号卫星摄影原理的分析,建立了在轨标定高分辨、多光谱相机与三线阵正视相机夹角的几何模型,并利用天绘卫星影像数据进行了相关试验。试验结果表明:该方法可行,精度较高,与可供参考的地面实验室定标结果较为接近,高分辨相机与三线阵正视相机夹角标定的两种结果相差1'左右,多光谱相机与三线阵正视相机夹角标定的两种结果相差5'左右。同时,计算分析了卫星定轨误差和地面控制点精度对夹角的影响。该方法模型简单,易于理解,解决了目前天绘一号卫星高分辨、多光谱相机与三线阵正视相机夹角仅有地面实验室标定结果,缺乏有效在轨标定方法的问题,对于影像的融合、纠正及高级产品的生产具有重要意义。     

Effect of the blooming of chemical curatives on the cyclic fatigue life of natural rubber filled with a silanized silica nanofiller

When partly soluble chemical curatives are mixed with raw rubber, they migrate to the rubber surface, which can be detrimental to the rubber properties. Two rubber compounds with different amounts of curatives were prepared by mixing natural rubber with a high loading of precipitated amorphous white silica nanofiller. The silica surfaces were pretreated with bis(3‐triethoxysilylpropyl)‐tetrasulfide coupling agent to chemically adhere silica to the rubber. The chemical bonding between the filler and rubber was optimized via the tetrasulfane groups of bis(3‐triethoxysilylpropyl)‐tetrasulfide by adding accelerator and activator. The rubber compounds were cured and stored at ambient temperature for up to 65 days. One compound showed extensive blooming as a function of storage time. The cyclic fatigue life of the rubber vulcanizates was subsequently measured at a constant strain amplitude and test frequency at ambient temperature. The blooming of the chemical curatives reduced the cyclic fatigue life of the rubber vulcanizate by more than 100%. The migrated chemical curatives produced a thin layer approximately 15 μm in size beneath the rubber surface. When the rubber was stressed repeatedly in the fatigue test, cracks initiated in this layer and subsequently grew, causing the fatigue life of the vulcanizate to decrease. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Effects of Chlorinated Paraffin and ZDDP Concentrations on Boundary Lubrication Properties of Mineral and Soybean Oils

Concentration effects of chlorinated paraffin and zinc di-ethylhexyl dithio phosphate on boundary lubrication properties were tested in vegetable and mineral base stocks. Solvent refined low sulfur paraffinic mineral oil (150 N oil) and conventional food grade soybean oil (soy oil) with EP additive concentration of 0–20% (w/w) were used in ASTM D2783 four-ball extreme pressure (4-ball EP) and Twist Compression Tribotests (TCT). Weld points in 4-ball EP and times to failure in TCT at 200 MPa showed that 150 N oil needed more than double treat levels of EP additives to achieve similar boundary lubrication performance as their 5% blends in soy oil. Also, incorporation of 20% soy oil into 150 N oil-based EP additive blends improved the performance to nearly the same level as soy oil only blends of corresponding additives. Boundary lubricity of some soy oil samples was similar to that of a commercial straight oil chlorinated metal forming lubricant. Several suggestions are provided to explain such pronounced influence of the base stock type on EP additive response. The findings suggest that soy oil and other farm-based oils may provide strategies for formulating cost effective industrial fluids and other lubricants.     

Elastohydrodynamic Study of Blends of Bio-Based Esters with Polyalphaolefin in the Low Film Thickness Regime

The film thickness in elastohydrodynamic (EHD) conditions for soybean oil (SBO), oleic estolide ester (EST) and their binary blends with polyalphaolefins (PAO2 or PAO40) were studied at 30 and 100 °C. Changes with time, for up to 200 min, were monitored. SBO and its blends with the lower viscosity PAO2 showed initially good agreement with the Hamrock–Dowson (H–D) equation down to 1–3 nm film thickness. 60 min or more after the start of the measurements, boundary layers with thickness up to 4.7 nm were observed. The blend of SBO with the more viscous PAO40 showed initially a good agreement with H–D at 100 °C. Negative deviations in film thickness were observed 15 min after the start of the measurements. At extended periods of time, up to 200 min, they were less pronounced but still detectable. EST–PAO2 blend showed initially formation of boundary layers with thickness around 2 nm. The boundary layer at 30 °C did not change for 200 min, while at 100 °C showed a decrease in thickness and/or viscosity with time. The EST and the EST–PAO40 blends showed good agreement with the H–D equation and did not display a boundary or fractionation layer within 200 min.     

用Monte-Carlo方法计算正电子湮没寿命谱中的衬底效应

用Ｍｏｎｔｅ－Ｃａｒｌｏ方法模拟计算了＾３２Ｎａ源的正电子在不同厚度Ｍｙｌａｒ膜,Ｎｉ膜衬底中的湮没几率,得出Ｓｉ,Ｆｅ、ＰＥ,ＰＰ４种样品在不同Ｍｙｌａｒ膜厚度下的衬底效应。结果,对ＰＥ、ＰＰ样品衬底铲应较Ｓｉ、Ｆｅ等样品强,表明用Ｍｏｎｔｅ－Ｃａｒｌｏ方法计算衬底效应是可行的。     

超声降解条斑紫菜多糖的反应动力学

针对多糖化学降解、热裂解和生物降解存在的一些不足,采用超声波技术研究了紫菜多糖（PYPS）的降解问题。研究了以下几个基础问题：（1）PYPS浓度、超声功率和溶液温度对降解过程中反应产物特性粘度随处理时间变化的影响;（2）用于描述PYPS分子量与特性粘度之间关系的Mark-Houwink方程的建立;（3）超声降解反应动力学方程的建立;（4）超声降解反应活化能的计算。结果表明,超声功率和溶液温度的增加有利于PYPS超声降解作用的增强,浓度的影响不是单调变化的,在0.75g/dL时降解较快;PYPS在水溶液中25℃下的Mark-Houwink方程参数为KMH＝7.86×10-3和α＝0.626;超声降解动力学研究发现,反应速率常数与反应时间之间呈显著的指数关系;超声降解反应的活化能为52.13kJ/mol。超声降解反应的活化能的数值小于两例发表的酶解法活化能,初步认为超声降解法优于酶解法。     

电池托架有限元分析与轻量化研究

以8 t平台纯电底盘电池托架为研究对象,基于有限元分析,对其强度性能进行了评估,研究了使用高强钢和结构优化等轻量化方法.结果表明:该轻量化方法实现了降重54 kg,经过强度评估后满足设计要求,为纯电底盘的轻量化设计提供了一条可行的途径.     

Improving time-domain measurements with a network analyzer using arobust rational interpolation technique

A method to efficiently and accurately compute a time-domain waveform from a network-analyzer frequency-domain measurement is presented in this paper. The method is based on a robust interpolation technique to construct a pole-residue representation of the response of the device-under-test. First, the rational function is expressed in terms of Chebyshev polynomials, instead of the usual power series, to accurately determine the poles of the network over a wide frequency range. The properties of a passive system are then utilized to efficiently calculate the residues. The resulting pole-residue model is analytically transformed to obtain the time-domain response in any time window, beyond the limitations of the discrete Fourier transform (DFT) technique. Unlike the DFT technique, the method does not require a large number of equally spaced harmonically related frequency points. The parametric model can also be used to economically store large measurement data. The proposed procedure is computationally inexpensive and less sensitive to numerical instability. To illustrate the validity of the method, examples of frequency- and time-domain measurements of a Beatty structure and simulation data of a low-pass Butterworth filter are given     

Radical-Initiated Reaction of Methyl Linoleate with Dialkyl Phosphites

The addition of dialkyl phosphite (methyl, ethyl and n‐butyl) to methyl linoleate (MeLin) double bonds was investigated. The reaction proved to be more challenging than the analogous reaction with methyl oleate (MeOl), due to inhibition of the radical reaction by the bis‐allylic hydrogens of MeLin and the lower reactivity of MeLin double bonds. However, we demonstrated that this self‐inhibition problem can be solved by simply keeping the MeLin reagent at low concentrations, while keeping the dialkyl phosphite at high concentrations. For optimization of the reaction, four different radical initiators were investigated: dilauroyl peroxide (LP), 2,2′‐azobis(2‐methylpropionitrile) (AIBN), tert‐butyl perbenzoate (t‐BP), and tert‐butyl peroxide (TOOT). The initiators were used at temperatures that provided a half‐life of 10 h: 64, 64, 104, and 125 °C respectively for LP, AIBN, t‐BP, and TOOT. The tests showed the reaction to be faster at higher temperatures, but transesterification of the ester groups was also observed at elevated temperatures. t‐BP was chosen as an optimal initiator for carrying the reaction. The apparent order of reactivity of the dimethyl, diethyl and di‐n‐butyl phosphites (Me >Et >n‐Bu) towards MeLin was due to differences in their molar volumes. When the concentrations of dialkyl phosphite were kept the same, the order reversed (n‐Bu > Et~Me). GC–MS spectra of the resulting phosphonates are reported and the main fragments assigned.