碱性溶液中硼氢化钠在铜阳极上的氧化行为

Polarization data of BH^-₄ oxidation on Cu anode in alkaline solution were measured at steady state by a self-made experimental cell. The experimental polarization curve showed three regions：the region at lower over-potential η（below 0.4 V approximately）,the region at higher η（above 0.6 V approximately）and the transitional region at medium η. It was found that the limiting current density is caused by the limiting elemental step rather than the external mass transport. The apparent reaction order with respect to BH^-₄ changes from 0 to 1. The active energy is about 40 kJ·mol^-1 in both regions with lower and higher η,and is higher than 40 kJ·mol^-1 in the transitional region. With the experimental temperatures and NaOH concentration,the hydrogen production rates released by the electrode reaction were measured at ［BH^-₄］/［OH^-］ratios of 1∶40,1∶20,1∶6. 7 and 1∶4,which is strongly dependent on the over-potential. The apparent number of released electron n by the reaction was calculated by using the measured amounts of hydrogen and coulomb. Higher value of n was obtained at lower ［BH^-₄］/［OH^-］ratio,higher temperature as well as higher over-potential. Under the experimental conditions,the value of n varies from 0 to 7,while in the transitional region it is just in the range of 3 to 5. The experimental results indicate that the limiting current density or n value will increase by virtue of proper experimental conditions. However,to considerably increase the current density at lower over-potential requires a modified anode with higher activity.     

可变的分子连接性指数在有机化合物反磁磁化率拓扑研究中的应用

For predicting the molar diamagnetic susceptibilities of organic compounds, a variable molecular connectivity index ^mχ^′ and its converse index ^mχ^″ based on adjacency matrix of molecular graphs and the variable atomic valence connectivity index δ^′I were proposed.The optimal values of parameters a, b, and y included in definition of δ′_i,^mχ^′and ^mχ^″can be found by optimization method.When a=1.10, b=2.8, and y=0.36, a good five-parameter model can be constructed from ^mχ^′and ^mχ^″by using the best subsets regression analysis method for the molar diamagnetic susceptibilities of organic compounds.The results showed that the current method is more effective than literature methods for estimating the molar diamagnetic susceptibility of an organic compound.     

288 K下Li+,K+//CO2-3,B4O2-7-H2O四元体系的相平衡

Solubilities and properties (density, conductivity and pH value) of solutions in the quaternary system Li⁺,K⁺//CO^2-₃,B₄O^2-₇-H₂O at 288 K were experimentally studied with the isothermal equilibrium method. The phase diagram of the system consisted of two invariant points E and F, five univariant curves, and four crystallization fields that belonged to K₂CO₃·3/2H₂O,Li₂B₄O₇·3H₂O,K₂B₄O₇·4H₂O and Li₂CO₃. The composition of the solution corresponding to E was w（CO^2-₃）=2.27 %,w（B₄O^2-₇）=6.05 %,w（K⁺ ）=4.30%,w(Li⁺)=0.30 % and the equilibrium solids were Li₂B₄O₇· 3H₂O+K ₂B₄O₇·4H₂O+Li₂CO₃;The composition of the solution for F was w(CO^2-₃)=22.45%,w(B₄O^2-₇)=1.88%,w(K⁺ )=29.96%,w(Li⁺ )=0.03% and the equilibrium solids were K₂CO₃·3/2H₂O+K ₂B₄O₇·4H₂O+Li₂CO₃. K₂CO₃ possesses strong salting-out effect on K₂B₄O₇,Li₂CO₃ and Li₂B₄O₇.     

超高温灭菌乳货架期加速试验的研究

In order to estimate the shelf-life of cow milk sterilized by instant treated with Ultra Heat Temperature(UHT) in a relatively short time, the accelerated shelf-life testing (ASLT) was designed and conducted, selecting the histological change of the sterilized milk caused by fat droplets creaming as its criteria.The stability index (SI) and the viscosity variation of the sterilized milk were determined at preservation conditions of 20, 25, 30, 35, 40 and 45℃, using Turbiscan technology.The result showed that the SI was slightly higher for 25℃ than for 20℃, elevating linearly for temperature from 25℃ to 40℃, and decreased for 40℃ to 45℃.The SI data for 25℃ to 40℃ were fitted well with equation SI_t=0.062t-1.382 (R²=0.990).If a ratio SI_t/SI_25℃ called as accelerated ratio (AR) was defined, the AR values calculated from the equation were 3.6,4.3 and 5.0 for 35, 37.5 and 40℃, respectively, which were agreement with the data from ASLT.So, the model could be used for the prediction of the shelf-life of sterilized milk by UHT process.     

利用翅片管束外表面降膜反应脱除烟气中SO2的实验研究

A new wet flue gas desulfurization method by reaction across the falling liquid film on the outside surface of axial finned-tube bundle and its principles of removal of SO₂ are presented in this paper.The effects of different styles of tube bundle,and the pitch of tubes,flue gas velocity,gas-liquid ratio and flue gas temperature on desulphurization efficiency and the moisture content of flue gas are studied.The experiment results show that desulphurization effect is better for flue gas at 65℃,4.0m·s^-1 against the tube bundle of 10 rows with relative pitch of staggered rows S₁/d=2.1,S₂/d=1.8.     

气固流化床混沌动力结构突变分析

A new method called structural catastrophe analysis was applied to the analysis of pressure fluctuation time series with chaotic and fractal characteristics in gas-solids fluidized bed.In every type of fixed bed,bubbling bed,turbulent bed,fast fluidized bed and pneumatic conveying stage,pressure fluctuation signals were sampled and dynamic exponents were solved.The changes of T_mean and T_max in different types of fluidized bed were analyzed and summarized.It was concluded that T_mean and T_max can indicate different types of fluidized,and T_max can also be recognized as a new characteristic parameter in addition to correlation parameters,LE exponent and K entropy.     

同轴双通道喷嘴雾化滴径沿轴向分布特性

Experiments were performed on the breakup of water droplets in a coaxial twin-fluid air-blast atomizer by a high-speed gas stream.With the measurements of Sauter mean diameter（SMD）distributions at a downstream distance of the atomizer,the droplet size was found first to decrease,reaching a minimum,and then to increase monotonically with the downstream distance.Correlation of L_c where the minimum droplet size appeared as a function of aerodynamic Weber number and liquid Reynolds number was analyzed.The growth rate of droplet size passes by L_c downstream increased with increasing water velocity,and the relationship between SMD and x/D_g accurately reflected the increasing trend of droplet size.     

回料流入口高度对循环流化床提升管流动特性的影响

The axial pressure drop profile and the radial solids distribution were measured in a circulating fluidized bed for evaluating the effects of return gas-solids stream position on the riser flow properties.The saturation carrying capacity of gas for Geldart B typed particles and the flow mode of return gas-solids stream in the bed were discussed.It was found that arranging the inlet at a higher position of the riser would make the bottom bed leaner when U₀ was high and G_s was low.When G_s increased,the longer influenced region of return particles and a small air-staging through lifting the loosening air injection position made the bottom bed become denser significantly.The deceleration and residence of return particles caused a relatively denser but asymmetrical region in the vicinity of inlet.But much more symmetrical solids distribution profile was found in the upper and lower regions far away from the inlet.The effects of inlet height on the flow properties of the riser with air-staging also were analyzed.The secondary air injection below the solids inlet could not cut off the solids exchange in the bed.The bed solids concentration increased when the particles inlet moved to a higher position of the bed when air-staging was adopted.Using CO₂ as tracer,the dispersion of the loop-seal-fluidizing air for transmitting the return particles was investigated.It was found that the loop-seal fluidizing air dispersion rate was low but can be enhanced by the secondary air injection.     

高颗粒通量循环流化床的构型作用

In order to achieve high solids circulation rate (G_s),an idea of coupling a moving bed to the bottom section of the riser of a circulating fluidized bed (CFB) was proposed and tested.The results from the preliminary study demonstrated that the solids circulation rate in the new-structure bed approached 370 kg·m^-2·s^-1 at superficial gas velocities around 10.5 m·s^-1 for sand particles with an average Sauter mean size of 378 μm.This study was devoted to further justifying the effects of the coupled moving bed by performing comparative studies in two CFBs with conventional configurations.It was shown that the pressure at the riser bottom and the realized solid circulation rate were only about 15 kPa and 230 kg·m^-2·s^-1 in the two conventionally configured CFBs,obviously lower than 25 kPa and 370 kg·m^-2·s^-1 in the moving bed coupled CFB.These verified that the coupled moving bed increased the force driving particles form the particle recycling side into the riser.The study further tested the effect of a few specially designed riser exit configurations,revealing that a smooth riser exit could facilitate solids circulation to increase the solids circulation rate.     

纳米CeO2搀杂对Ni-P化学镀层微观结构与耐蚀性能的影响

Ni-P and its nano-CeO₂ doped coating were electrolessly prepared in acidic condition,and their microstructure and anti-corrosion property were studied and compared.Scanning electronic microscopy（SEM）,transmission electronic microscopy（TEM）,X-ray diffraction spectrometer（XRD）and differential scanning calorimeter（DSC）were used to examine surface morphology and microstructure of coatings.The results showed that Ni-P coating had partial amorphous structure mixed with nano-crystals,while the Ni-P/CeO₂ coating had perfect amorphous structure.Upon heating,Ni₃P precipitation and Ni crystallization took place in both coatings but at different temperatures of phase change.In addition,the Ni-P/CeO₂ coating had sintered phase of NiCe₂O₄ spinels.The anti-corrosion property and passivity were improved in the CeO₂-doped coating because it was less liable to undergo localized corrosion and had a slower corroding rate than its CeO₂-free counterpart.During the co-deposition process,some Ceⁿ⁺（n=3,4）ions might be adsorbed to the metal/solution electrical double layer and hinder nickel deposition.Ni-P/CeO₂ coating’s perfect amorphous structure was probably due to the hindered crystal-typed deposition of nickel and the promoted deposition of phosphorous.     

AIBA·2HCl-NaHSO3引发下DMDAAC-AM共聚物的合成与表征

采用偶氮二异丁脒二盐酸盐(AIBA·2HCl)和NaHSO₃(RH)组成的引发体系，研究了引发剂浓度、溶液的pH值、引发剂复配和加料方式等因素对二甲基二烯丙基氯化铵(DMDAAC)-丙烯酰胺(AM)共聚合反应规律的影响.结果表明：在30 ℃、n_AM∶n_DMDAAC=4∶1、ω(monomer) =30％和引发剂AIBA·2HCl-RH的浓度为1.0×10^-4 mol·L^-1的条件下， pH=7.0时， DMDAAC-AM共聚物的特性黏数达11.56 dl·g^-1;pH=10.0时，特性黏数最高达13.60 dl·g^-1.采取连续加料方式，可获得阳离子度38.8％，特性黏数达11.61 dl·g^-1的共聚物.进一步测得该引发体系30 ℃下，聚合反应的表观活化能为33.25 kJ·mol^-1，单体的竞聚率为γ_AM=6.800，γ_DMDAAC=0.174.     

反相悬浮共聚法合成耐盐快吸水性树脂

以AA(丙烯酸)、AMPS(2-丙烯酰胺-2-甲基丙烷磺酸)为单体,APS(过硫酸铵)为引发剂,MBAM(N,N-亚甲基双丙烯酰胺)为交联剂,十八醇磷酸单酯为分散稳定剂,环己烷为连续相,采用反相悬浮法合成吸盐水率高、吸水速率快的共聚型吸水树脂.研究了单体组成、交联剂浓度、AA中和度（Dn）、引发剂浓度、共聚温度(T)、油水相体积比对树脂吸盐水率和吸水率、吸水速率及物理性状的影响.当w(AMPS)=40%、c(MBAM)=1.62mmol• L^-1、Dn=75％、c(APS)=24.70mmol•L^-1、T=65℃、V(油)∶V(水)=1.5∶1.0时,共聚物的吸盐水率和吸水率分别为：A_生理盐水=264ml• g^-1,A_蒸馏水=1200ml•g^-1,15min可吸水饱和.通过热分析发现,提高共聚物的交联密度利于改进共聚物的保水性.     

羽毛蛋白接枝聚丙烯酸-丙烯酰胺树脂的合成与吸水性能

以改性羽毛蛋白(MFP)、丙烯酸（AA）和丙烯酰胺(AM)为主要原料,N,N′-亚甲基双丙烯酰胺为交联剂,硫酸钾-亚硫酸氢钠为引发剂,采用溶液聚合法制备了羽毛蛋白接枝聚丙烯酸-丙烯酰胺高吸水树脂［P(MFP-g-AA/AM)］,并对其吸水性能及其影响因素进行了考察。结果表明,P(MFP-g-AA/AM)制备的最适宜工艺条件为W_AA∶W_AM=70∶30,丙烯酸的中和度为90％,W_MFP∶W_AA+AM=10%,W_initiator∶W_AA+AM=0.8%,W_crosslinker∶W_AA+AM=0.10%,反应温度为60℃,反应时间为2 h。在此条件下合成的P(MFP-g-AA/AM)树脂在去离子水中的饱和吸水倍率为578.0 g•g^-1,吸盐水（0.9％NaCl）倍率为78.6 g•g^-1,吸人工尿液倍率为75.1 g•g^-1,均高于羽毛蛋白接枝丙烯酸树脂。     

降解淀粉/DMDAAC-AM接枝共聚物复鞣剂的合成及应用

酶降解淀粉与二甲基二烯丙基氯化铵(DMDAAC)和丙烯酰胺(AM)在引发剂(NH4)2S2O8(APS)作用下进行了接枝共聚合反应,制得阳离子型淀粉复鞣剂。第一步酶降解条件为m(蒸馏水)∶m(淀粉)∶m(α 淀粉酶)=180∶20∶0 2,在60℃降解1h。第二步接枝聚合反应条件为m(DMDAAC)∶m(AM)∶m(APS)=40∶20∶1 5,在75℃保温反应2h。接枝共聚物的接枝率及接枝效率分别为150%和78%,单体转化率及阳离子度分别为98 5%和37%,复鞣革对于染料及加脂剂的吸收率分别为97 3%和96 2%,用红外光谱(FTIR)对复鞣剂的结构进行了表征。     

季铵型淀粉基强阳离子高分子聚合物的制备及应用

用自制的引发剂,通过溶液聚合反应合成了淀粉、丙烯酰胺(AM)、二甲基二烯丙基氯化铵(DMDAAC)季铵型淀粉基强阳离子高分子聚合物,并通过红外光谱对其进行了表征。最佳反应条件为:接枝共聚反应引发剂用量为0.15%,m(淀粉)∶m(AM+DMDAAC)=3∶7,m(AM)∶m(DMDAAC)=7∶3,反应时间4 h,反应温度50℃。产物对油田污水中油和固体悬浮物的去除率优于阳离子聚丙烯酰胺(CPAM)。     

油酸盐用于淀粉接枝AM-AA反相乳液共聚反应乳化剂

引　言淀粉是一类重要的天然高分子 ,在造纸、食品、纺织等工业领域中具有广阔的应用前景[1] .淀粉的接枝共聚物是一类新型的高分子材料 ,在高分子絮凝剂、高吸水材料、造纸工业助剂、油田化学材料、可降解地膜和塑料等多方面的实际应用中具有优异的性能[2 ] .部分水解聚丙烯酰     

反相乳液五元体系淀粉接枝共聚反应动力学

研究了在淀粉/单体/乳化剂/油/水五元反相乳液体系中引发淀粉和丙烯酰胺接枝共聚反应的动力学,考察了引发剂和乳化剂浓度、单体和淀粉浓度、反应温度等因素对表观聚合速率的影响.结果表明：在本实验考察范围内单体浓度和淀粉浓度对聚合速率影响明显,聚合过程中快速链终止和慢速链终止反应同时存在,动力学关系式为：R_p∝［I］^0.93［M］^1.28［St］^1.47［E］^0.61,聚合速率随体系温度的升高而加快,在35～55℃范围内,聚合反应的表观活化能为82.01 kJ•mol^-1.     

水溶性两性高分子的合成和溶液性质

等物质的量的二甲胺和氯丙烯在碱性条件下反应生成烯丙基二甲胺 ,转化率为 6 8 7%;烯丙基二甲胺与氯乙酸钠〔n(烯丙基二甲胺 )∶n(氯乙酸钠 ) =1∶0 8〕在 6 0～ 70℃进行季铵化反应 ,合成了两性离子单体N 羧甲基 N ,N 二甲基 N 烯丙基氢氧化铵内盐 (CDAH) ,转化率 96 5 %(以氯乙酸钠计 )。以水为溶剂 ,亚硫酸氢钠和过硫酸钾为引发剂 ,合成了N 羧甲基 N ,N 二甲基 N 烯丙基氢氧化铵内盐—丙烯酰胺 (AA)两性共聚物 ;聚合条件为 :聚合温度 6 0～ 80℃ ,单体量比n(CDAH)∶n(AA) =3∶7,单体的质量分数w (CDAH +AA) =30 %,引发剂NaHSO3 和K2 S2 O8的质量均为单体总质量的 0 2 %。研究了两性高分子在不同介质中的黏度特性。结果表明 ,两性共聚物的等电区 (pH值 )为 5 5～ 7 5 ;非等电区时共聚物在纯水中具有典型的聚电解质黏度特性 ,随外加盐阴离子半径的增大 ,或随盐溶液浓度的增大 ,比浓黏度和特性黏度减小 ,Huggins常数增大 ;等电区时共聚物在纯水中的黏性行为符合Mark Huggins方程 ,外加盐的影响与非等电区时相反。     

MA-AM-AA三元共聚物的制备及阻垢性能

以马来酸酐(MA)、丙烯酸(AA)和丙烯酰胺(AM)为原料,研制出环保型三元共聚阻垢剂PMAA,并通过研究其阻垢性能确定了产品的最佳工艺配方。实验结果表明,当单体的质量配比m(AA)∶m(AM)∶m(MA)=2∶3∶0·5,引发剂用量为单体总质量的1.5%,反应温度为80℃,单体质量分数为15%时,得到的聚合物PMAA的用量为5mg/L时,用国标法测得其对碳酸钙的阻垢率达94·15%,对磷酸钙的阻垢率达80·93%。     

Fenton处理对氯酚过程中间产物对Fe3+的还原作用

为探明Fenton处理对氯酚（4-CP）过程中Fe²⁺再生的途径,考察了反应过程Fe²⁺的浓度变化,同时对4-CP降解中间产物和Fe³⁺之间的氧化还原反应进行了研究.Fenton氧化对氯酚过程中Fe²⁺的浓度基本不变;而在•OH捕获剂丙醇的存在下,反应开始后1 min Fe²⁺的浓度急剧下降到10％.研究结果表明：H₂O₂、•OH、HO₂•与O^-₂•等自由基对Fe²⁺的再生净贡献较小,4-CP降解的中间产物对Fe³⁺的还原是Fe²⁺再生的主要途径.Fenton处理4-CP产生的中间产物有对苯二酚和对苯醌.对苯二酚能够快速还原Fe³⁺,使Fe²⁺得到再生;而对苯醌还原Fe³⁺的作用很微弱.这一研究有助于更好地了解Fenton氧化过程中Fe²⁺的再生.