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71.
Synthetic polymers have recently drawn increasing attention to chemical sand stabilization (CSS). The relationship between the molecular structure and the fixing effect, however, is rarely reported aside from the performance. In this article, different segments of waterborne polyurethane dispersions (PUDs) are discussed with respect to their influence on stabilizing sand. We prepared five PUDs by controlling parameters including the diisocyanate-to-polyol ratio (R) and the molecular weight and characterized them with Fourier transform infrared spectroscopy and laser particle analysis. The unconfined compressive strength (UCS), a key criterion in CSS, was used to evaluate the performance of the PUDs. We found that a bigger R gave the polyurethane (PU) film a higher strength than the smaller R but did not do the same to the sand mold. This indicated that homogeneity was a primary property of the sand mold. Taking the details of the crushed sand molds and the PU films into account, we concluded that the soft segments played a major role in the homogeneity. Force analysis showed that four modes of breaking occurred at the interface of the sand and cured PU. We concluded that whereas the hard segments in PU determined the ceiling of the UCS, the soft segments determined the floor by benefiting adsorption. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47267.  相似文献   
72.
Li4SiO4 has been widely studied as attractive tritium breeding materials due to its innate merits. Considering the potential advantages of nanostructure in tritium breeding materials, a distinctive process was developed to obtain nanostructured Li4SiO4 pebbles. In brief, ultrafine precursor powders were synthesized by solvothermal method without using surfactants, and then indirect wet method was adopted to generate the green spheres with homogeneous microstructure. After that, the suitable sintering conditions were defined by studying the effects of sintering parameters on the grain size evolution, and nanostructured Ti-doped Li4SiO4 pebbles were first obtained by two-step sintering method. This study will be expected to provide references for fabricating other Li-based tritium breeding materials.  相似文献   
73.
LHWC水泥厂余热发电项目热工检测和效益评估   总被引:1,自引:0,他引:1  
对LHWC水泥厂2500t/d新型干法窑的热工标定数据分析,熟料产量超过3000t/d以上,已经超过设计产量指标20%,产量指标达到了国内先进水平。C1筒出口废气温度降低到300℃左右,显著降低了预热器废气热损失;各级预热器的换热效率比较高,但是其阻力损失也比较大。篦冷机的热回收效率比较低,高温风机也没有多少富余。若增加余热发电系统,必须更换高温风机或者对系统进行优化以降低系统的阻力。从余热发电的效益评估来看增加余热发电系统,只需两年半到三年半就可回收成本。  相似文献   
74.
Amino-modified silica hydrogel (N-MSHG) was prepared by a simple sol-gel processing via the co-condensation of commercial silica sol with 3-aminopropyltrieoxysilane. Penicillin G acylase (PGA), a model enzyme, was covalently immobilized onto the N-MSHG and then was used for the enzymatic synthesis of amoxicillin. The samples were characterized by Nitrogen sorption analysis, FT-IR and thermal gravimetric analysis (TGA). The results showed that the amino-modified gel was a mesoporous material with an average pore size of 12.64±0.17 nm. The immobilization process was efficient and the immobilized enzyme showed high catalytic efficiency. The yield of the synthesis of amoxicillin in aqueous media was 38% for 2.5 h. This sol-gel preparation is simple and shows prominent potential value in industrial processing.  相似文献   
75.
A new pillar-layered coordination framework [Er(H2O)(C5H2N2O4)(TA)0.5]n (1) has been hydrothermally synthesized by employing imidazole-4,5-dicarboxlylate (H3IDC) and terephthalate (H2TA) and structurally characterized. Single crystal X-ray diffraction analysis reveals that compound 1 exhibits the 2D pillar-layered coordination framework with meso-helical character constructed from auxiliary ligand TA2? (that is, pillar) bridging two [Er(HIDC2?)]n layers (namely, Δ- and Λ-layers), which is the first example of lanthanide coordination framework including imidazole-4,5-dicarboxlylate and terephthalate. Meanwhile, the thermogravimetric analysis shows compound 1 has high thermal stability.  相似文献   
76.
The discharging process of polyvinyl pyrrolidone electret under two different heating rates 3.5 and 2 °C/min has been investigated by the measurement of thermally stimulated depolarization current (TSDC) in the temperature range from 30 to 250 °C. The TSDC spectra of PVP shows three peaks located at 70 ± 10, 150 ± 10, and 230 ± 10 °C, respectively. When explaining the TSDC spectra, this thesis deduced that the first peak, β peak, originates from side group relaxation; the second peak, α peak, corresponds to the relaxation of the frozen dipoles on the molecule chain segments during glass transition; the third peak, ρ peak, is attributed to the detrapping of the trapped space charge under thermal stimulation. The current of the ρ peak is remarkably strong due to the fact that PVP molecules’ side groups—the pyrrolidone rings containing lactam structure—are strong polar groups which cause the great increase in the number of bulk traps, trapped space charge, as well as detrapped space charge under thermal stimulation.  相似文献   
77.
齿轮接触斑点可以作为评价齿轮承载能力的一项重要指标.迄今为上,接触斑点的测量仅限于目视观察,所以精度很低.本文介绍一种全新的、基于激光扫描的接触斑点自动测量装置。并对该装置的测量原理作了简要讨论。  相似文献   
78.
长弓 《包装世界》2006,(4):14-14
在最近召开的"建设节约型社会与交通节能国际柴油发展论坛"会议上,国家发展改革委能源局徐锭明局长在报告中指出:加快建设资源节约型社会,我国将采取四大节约能源的政策措施.  相似文献   
79.
Gong M  Lu F  Liu Q  Gong W  Li C 《Applied optics》2006,45(16):3806-3810
A high efficiency Yb:YAG/YAG composite slab laser is presented, in which the corner-pumped scheme is adopted. The slab is a composite crystal of Yb:YAG bonded thermally with undoped YAG at both edges. The pump light from diode arrays is coupled into the slab through four chamfers at the four corners independently. The pump absorption efficiency is studied, and an analysis method has been developed as a guide to optimize the geometric parameters of the composite slab, to obtain higher pump absorption efficiency and uniformity. The influence of the internal thermal lens on the laser resonator is analyzed. A 1016 W continuous-wave output has been obtained with the slope efficiency and optical-to-optical efficiency of 42.8% and 34.4%, respectively.  相似文献   
80.
介绍了齐鲁石油化工公司 0 .6Mt/a连续重整装置的设计和满负荷标定情况以及装置尚需解决的问题。该装置采用法国石油研究院的连续重整第二代再生技术 ,与以往的引进方式不同 ,这次引进只付专利费 ,不购买与专利有关的工艺包 ,全部技术方面工作由国内负责。该装置设计在充分消化吸收引进技术的基础上 ,开发了并列式连续再生控制系统 ,改进了再生系统关键设备及催化剂粉尘收集系统的设计及采用了国内多项先进技术。运行和标定结果表明 ,设计达到国际先进水平  相似文献   
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