基于Rosin-Rammler的离散元扩大头抗浮锚杆抗拔力学特性影响研究

目前,抗浮锚固技术已被广泛应用于工程建设中。然而,学界对扩大头抗浮锚杆与不同级配土体相互作用的力学机制的研究尚不充分。因此,文章针对扩大头抗浮锚杆与土体级配的相互作用展开了研究。首先通过Rosin-Rammler函数构建级配曲线,并以曲线形状参数m值表征土体颗粒的不均匀性,然后进行拉拔数值模拟。结果表明,在拉拔过程中,m值越大,土体颗粒越不均匀,并且拉拔承载力随着m值的增大而减小。同时,速度传递区域由类锥形转为类矩形分布,接触力链由粗支网状转为细支网状。

Synthesis and Properties of Rosin-Based Composite Acrylamide Hydrogels

Hydrogels have been widely applied in agricultural drought-resistance,pollution regulation,drug delivery and so on.Acrylamide(AM)is usually used as raw material to synthesize acrylamide hydrogels.However,inherently low mechanical strength greatly limits their applications in some special areas.Therefore,it is necessary to choose suitable functional monomers to optimize acrylamide hydrogels and improve their mechanical performances.In this paper,a novel acrylamide monomer modified by rosin was synthesized,and then polyacrylamide/rosinbased acrylamide(RAM)composite hydrogels were prepared via free radical polymerization using potassium persulfate as initiator,N,N′-methylene-bisacrylamide(MBA)as a crosslinker.The influence of RAM monomer was investigated in detail.The chemical structure,pore structure,swelling properties,thermal performances and mechanical properties of composite hydrogels were characterized by Fourier Transform Infrared spectrometer(FT-IR),thermogravimetric analysis(TG),scanning electron microscope(SEM),and universal testing,respectively.The results showed that the thermal stability and mechanical property of RAM hydrogels were improved significantly.The compressive strength of RAM hydrogels was increased to 3.5 times than that of AM hydrogels,and the tensile strength was 5.1 times compared with AM hydrogels as well.Moreover,RAM hydrogels exhibited a faster initial swelling rate due to the new pore structure formed after introducing the RAM monomer.

运用Rosin-Rammler分布函数研究煤尘粒径分布规律

运用Rosin-Rammler分布函数对伯方煤矿3#煤层煤样进行粒径分布情况的分析,得出结论:在双对数lnd-ln{-ln[1-F(d)]}坐标系下,所研究的材料颗粒分布的回归曲线为一条直线,R2=0.9672,线性回归良好。并得到了所研究粒径分布的具体函数表达式。由此可以对该煤层的冲击产尘的粒径分布有一个总体上的量化认识,为指导实际生产降尘、除尘提供了理论上的依据。

Rosin-Rammler分布的实验拟合曲线优化

基于Rosin-Rammler分布函数,提出一种新的实验拟合曲线优化方法,以二氧化硅、钾长石粉、矿石粉和石英砂四种材料为例,对激光粒度仪实验测量数据进行分析和处理,并应用Matlab软件编程实现实验数据分析和处理自动化。拟合曲线、误差分析和文献对比结果表明,优化方法正确、合理,优化后的拟合曲线更接近实验测量曲线。该方法对于准确计算平均粒径和方差、客观评价粉体材料性能等实际应用具有重要意义。

基于Rosin-Rammler的海水冷却塔收水器流体力学性能研究

收水器是控制海水冷却塔性能及环境影响的重要塔内件。为探索其内部流动特征对性能的影响,采用试验与计算流体力学(CFD)方法,对海水冷却塔收水器流体力学特性进行研究。文中设计了海水冷却塔收水器压降性能的测试装置并对BO-45/160型收水器进行测试,运用Rosin-Rammler函数描述收水器内部液滴群的粒径分布,通过SST k-ω湍流模型及离散相(DPM)模型,建立CFD计算模型,与试验测试结果对比,模拟值与试验值达到较好的吻合效果,证明了CFD模型的准确性。随后,通过CFD方法考察波形、双波形、折线形收水器基本流道片型在多间距多高度条件下的流动形式,分析不同收水器型式在不同间距和高度下收水效率与压力降的影响因素,为新结构的开发提供数据支撑。

用双 Rosin-Rammler 函数求颗粒尺寸分布

用双Ｒｏｓｉｎ－Ｒａｍｍｌｅｒ分布函数不但可以求解具有双峰形式的颗粒尺寸分布，而且也可以求解具有单峰形式的实际颗粒系．模拟计算和实测表明，即便是求解单峰分布的颗粒尺寸，用双Ｒｏｓｉｎ－Ｒａｍｍｌｅｒ分布函数也明显比常用的单Ｒｏｓｉｎ－Ｒａｍｍｌｅｒ函数具有更高的反演算精度．

Sonochemical Synthesis of Maleated Rosin

The cycloaddition reaction of rosin and maleic anhydride under ultrasonic irradiation has been investigated. The results show that both isomerization and Diels-Alder cycloaddition reactions were accelerated remarkably. The sonochemical reaction reached equilibrium in 5-10 min at 110℃, comparing with regular synthesis of 4-5 h over 180℃.

Synthesis and Kinetics of Hydrogenated Rosin Dodecyl Ester as an Environmentally Friendly Plasticizer

The plasticizer is an important polymer material additive.Non-toxic and environmentally friendly plasticizers are developed recently in order to decrease fossil fuel reserves,serious environmental pollution and the toxicity of phthalate esters.In this study,a new,efficient and environmentally friendly plasticizer of hydrogenated rosin dodecyl ester was prepared by an esterification reaction of hydrogenated rosin and dodecanol.The influences of different reaction conditions(including different catalysts,the catalyst concentration,the ratio of the reactants,reaction temperature,and reaction time)on the esterification yield are examined and discussed.Hydrogenated rosin dodecyl ester with 71.8%yield was synthesized under the optimized reaction conditions(1:0.8 molar ratio of rosin to dodecanol,1 mol%tetrabutyl titanate concentration,and 210℃for 6 h).The esterification reaction is a second-order reaction,and kinetic calculations showed that the activation energy is 39.77 KJ·mol^(−1).The structure of the hydrogenated rosin dodecyl ester was confirmed by FT-IR spectroscopy and^(13)C NMR spectrum.Besides,the thermal stability of target product(hydrogenated rosin dodecyl ester)was also tested by thermal gravimetric analysis(TGA),which showed a good thermal stability.

Synthesis, characterization and application of a dispersant based on rosin for coal-water slurry

A rosin derivative and maleopimaric acid diethanolamide(MAD), was synthesized, characterized by FTIR and1 H NMR, and applied as dispersant for the coal-water slurry(CWS) prepared from Chinese Shenfu coal. The CWS application performance investigation shows that the MAD dispersant has better abilities in reducing CWS viscosity and stabilizing the slurry than a commercial dispersant—sulfonated naphthalene-formaldehyde condensate(SNF). The physicochemical property investigation of the two tested dispersants shows that the adsorption amount of the MAD at coal-water interface is much larger than that of SNF, and the MAD has better wetting property than the SNF on the coal surface. It indicated that the excellent capabilities of MAD are related to the adsorption mode of standing upright on the coal surface. Based on the above, the mechanism of dispersion and stabilization of the CWS prepared from MAD dispersant is presented.

FUNCTIONS OF POLYAMINES IN ROSIN SIZING UNDER NEUTRAL PAPERMAKING CONDITIONS

Functions of the polyamines in neutral rosin sizing were investigated using X-ray photoelectron spectroscopy (XPS) and laser diffraction particle analysis. The polyamine with a higher charge density and a smaller unite size could retain more rosin and cover larger fiber surfaces. The XPS spectra demonstrated that polyallylamine (PAAm) and polyvinylamine (PVAm) could react with a rosin size to form a -OC-N-CO- structure, but polydimethylamino ethyl methacrylate (PDMAEMA) could not. The formation of this structure may be a key step for effective sizing.

Development and Characterization of an Electrochemical Sensor for Cinchonidine Detection Based on Molecularly Imprinted Polymer with Modified Rosin as Cross-linker

Molecularly imprinted polymers（MIPs） were applied as molecular recognition elements to an electro- chemical sensor for cinchonidine（CD）. A kind of MIP was synthesized with cinchonidine as template, modified ro- sin（ethylene glycol maleic rosinate acrylate） containing the skeleton of phenanthrene rings as cross-linker and me- thylacrylic acid as functional monomer. MIP membrane was prepared on a glassy carbon electrode for the determina- tion of CD via free radical polymerization method. Electrochemical impedance spectroscopy（EIS） and cyclic vol- tammetry（CV） were used to characterize the membrane electrochemical behavior in electrode fabrication process. The experimental conditions were discussed. Under optimum conditions, it was found that the response of peak cur- rents was linear to the concentration of CD in a range of 0.013-2.26 mmol/L. The detection limit for CD is 1 μmol/L the relative standard deviation for 100 μmol/L CD is 1.34% and the incubation time is 2 min. The sensor was applied to the determination of CD in urine samples with satisfactory results.

The effect of rosin acid on hydrodeoxygenation of fatty acid

In this study, inhibition of tall oil fatty acid hydrodeoxygenation(HDO) activity due to addition of rosin acid over sulfided Ni Mo/Al_2O_3 was investigated. Oleic acid and abietic acid were used as model compounds for fatty acid and rosin acid respectively in tall oil. After completion of each HDO experiment,the Ni Mo catalysts were recovered and used again under the same conditions. The results showed that the oleic acid HDO activity of sulfided catalysts was inhibited by addition of abietic acid due to competitive adsorption and increased coke deposition. The rate of carbon deposition on the catalysts increased when abietic acid was added to oleic acid feed. Moreover, the coke was in a more advanced form with higher stability for the catalysts exposed to both oleic acid and abietic acid. Furthermore, a clear correlation between the rate of coke formation and concentration of abietic acid was observed.

Rosin side chain type catalyst-free vitrimers with high cross-link density,mechanical strength,and thermal stability

The emergence of vitrimer,a new class of polymer materials can address the problem of recyclability,reprocess ability and recyclability of thermosetting plastics.Rosin,a natural product,is an ideal raw material for the preparation of polymers in a more sustainable way.Nevertheless,due to the huge steric hindrance caused by the hydrogenated phenanthrene ring structure,the cross-link density of materials is frequently lowered.In this study,hydrogenated rosin was adopted for preparing hydrogenated rosin side-chain type diacids,which were reacted with mixed epoxy to obtain rosin side-chain type vitrimers.It was completely characterized by differential scanning calorimetry test,thermogravimetric analysis,shape memory test and self-healing test.The prepared vitrimers exhibited good self-healing properties,excellent heat resistance(T_(d)=352℃)as well as high mechanical properties(tensile strength of 46.75 MPa).The tricyclic diterpene structure of rosin was introduced into the side chain in order to avoid the reduction of cross-link density resulting from the huge steric hindrance of the rigid tricyclic hydrophenylene skeleton.Vitrimers can undergo dynamic transesterification reaction without external catalysts due to the autocatalytic effect of tertiary amines from epoxy.Moreover,our work expanded the application field of rosin,increased the added value of rosin,and provided a novel method for preparing rosin-based vitrimers with ideal properties.

利用改进的亮温日较差法探测格陵兰冰盖表面融化

格陵兰冰盖是全球海平面上升的主要贡献源之一,其表面融化和融水径流引发的物质损失约占冰盖总物质损失的60%,研究格陵兰冰盖的表面融化具有重要意义。采用2019年增强分辨率的专用微波成像仪37 GHz垂直极化被动微波数据,提出改进的亮温日较差(advanced diurnal amplitude variations,ADAV)方法,并利用该方法探测格陵兰冰盖的表面融化。与自动气象站的气温数据对比,ADAV方法使用动态阈值探测结果的平均精度高于使用固定阈值的传统日较差方法,且被动微波数据时间对探测精度无明显影响。采用该方法分析格陵兰冰盖冻融发现,2019年冰盖融化天数最多达165 d,7月31日融化面积达到最大,占冰盖总面积的67%;夏季3次出现融化峰值,且南部沿岸发生了冬季融化事件。

紫外分光光度法测定歧化松香中去氢枞酸含量的干扰因素研究

利用液相色谱仪、制备液相色谱仪、气相色谱质谱联用仪,对歧化松香(DR)中去氢枞酸(DA)紫外光谱测定方法的干扰因素进行了详细研究。测定的市售不同省份的5个样品中有2个主要干扰物质,进一步定性,确定干扰物质1为6,8,11,13-枞四烯酸(ATA),干扰物质2为混合物,主要检出物为去氢枞醛(D)和枞酸(AA)。采用二阶导数光谱法和偏最小二乘(PLS)法对紫外光谱数据进行分析,以消除去氢枞酸紫外分光光度法的干扰,结果表明:PLS法比二阶导数光谱法误差更小,能够同时消除多种干扰因素,使测试结果更加接近真实值。

马来海松基环氧树脂的制备与性能研究

在“双碳”发展战略目标的背景下,为探索绿色环保型生物基环氧树脂在电工设备上的应用前景,本文以可再生资源松香为原料,制备了一种生物基树脂——马来海松基环氧树脂(MPAER)。以甲基六氢邻苯二甲酸酐(MHHPA)为固化剂,对MPAER/MHHPA体系的固化特性、热性能、力学性能和电气性能进行了系统研究,并和商用双酚A二缩水甘油醚(DGEBA)组成的DGEBA/MHHPA体系进行对比。结果表明:MPAER/MHHPA和DGEBA/MHHPA体系的固化反应活性相当,MPAER/MHHPA体系的玻璃化转变温度为112.8℃,其力学性能和电气性能均稍弱于DGEBA/MHHPA体系,其中MPAER/MHHPA体系的电气强度比DGEBA/MHHPA体系低9.4%。但MPAER/MHHPA体系的综合性能仍较好,可以通过对MPAER进行结构优化或者与其他类型的环氧树脂共混来进一步提高其性能。

Preparation and Characterization of Biobased Dehydroabietyl Polyethylene Glycol Glycidyl Ether-Grafted Hydroxyethyl Cellulose with High Emulsifying Property

Dehydroabietyl polyethylene glycol glycidyl ether-grafted hydroxyethyl cellulose(HEC)polymer surfactant(DA(EO)5GE-g-HEC)was prepared using ring-opening polymerization with biobased rosin and hydroxyethyl cellulose as feedstocks.Dehydroabietyl polyethylene glycol glycidyl ether(DA(EO)5GE)was formed by condensation of dehydroabietyl alcohol polyoxyethylene ether(Rosin derivative:DA(EO)5H)and epichlorohydrin.The grafting degree of DA(EO)5GE-g-HEC was manipulated by adjusting the mass ratio of HEC and DA(EO)5GE and confirmed by EA.According to the formula,when m(HEC)/m(DA(EO)2GE)was 1:1~1:5,the grafting rate of DA(EO)5GE in DA(EO)5GE-g-HEC varied from 34.43%to 38.33%.The surface activity and foam properties of DA(EO)5GE-g-HEC aqueous solution were studied.The results showed that with the increase in grafting rate,the critical micellar concentration(CMC)in aqueous solution changed from 1.28 to 0.96 g/L.The results of the thermogravimetric analysis showed that the temperature range of the main stage of mass loss of DA(EO)5GE-g-HEC was 310°C~410°C,and the thermal decomposition processes of the samples with five mass ratios were similar.An oil in water emulsion was prepared by choosing cyclohexane as the oil phase and DA(EO)5GE-g-HEC as the emulsifier.The effect of DA(EO)5GE-g-HEC mass fraction on emulsion particle size and stability was analyzed.The results suggested that when the oil-water ratio was 8:2 with 0.4%emulsifier,the emulsion droplets were the smallest in terms of particle size and were the most stable.The rheological test results showed that the apparent viscosity decreased with the increase in shear rate and showed a typical elastic gel phenomenon.

两种添加剂对石蜡-硬脂酸蜡料性能的影响

为探究改性松香和聚乙烯对中温模料组织性能的影响,本研究以石蜡-硬脂酸二元系模料为基体,在此基础上逐步添加改性松香和聚乙烯,探究二元基体配比、改性松香及聚乙烯含量对模料熔点、抗弯强度、针入度和融合均匀性等物理特性的影响,在此基础上研制出一种针入度达1.06 mm、强度达6.02 MPa、熔点在58℃附近的综合性能良好的中温模料,为中温模料改良优化提供理论支持。

CO_(2)高速卸荷粉碎磁铁矿石产品的粒度分布与分形维数研究

针对矿石的高压气体高速卸荷粉化产品的整体粒径分布缺乏系统科学的表征,以某超贫磁铁矿石为原料、液态二氧化碳为工作物质,引入Rosin-Rammler分布函数和分形维数,系统地分析了不同液态二氧化碳渗透压力下所得产品的粒度分布特性。结果表明:粉化产品颗粒粒径分布不均匀,提高二氧化碳压力可以提高细颗粒产率。Rosin-Rammler分布函数可较好地拟合粉化产品的粒径分布,拟合结果表明,粒径分布的均匀性指数随着二氧化碳压力的提高而减小,粉体粒径更不均匀。针对粗颗粒产率较大情况下Rosin-Rammler分布函数表现出的不足,引入分形维数进行了分析。结果表明,随二氧化碳压力的增大,粉化产物的分形维数增大,粉体整体趋于细化。本研究结果可为后续科学系统评价二氧化碳高速卸荷粉化各类矿石的整体效果提供参考。

基于二维Rosin阈值方法的道路裂纹边缘检测

为了在道路裂纹图像边缘检测时选择准确的区分噪声与边缘阈值,针对一维Rosin算法不能充分利用图像局部结构信息的缺陷,将传统Rosin方法推广至二维,联合Canny边缘检测算法和Rosin算法,利用像素点本身及其邻域的局部结构信息建立图像二维直方图;利用直方图的最高点和最低点构造全角旋转阈值选取平面,以搜索直方图与各阈值平面的空间距离最大值确定阈值点,获得一种自适应的Canny算法中的阈值选取方法。研究结果表明:该算法可对道路裂纹边缘进行有效检测,并扩展Canny算法的应用范围。