四羟甲基硫酸鏻的合成及测定研究

以黄磷、锌粉、硫酸和甲醛为原料,成功合成了四羟甲基硫酸鏻(THPS),详细探讨了不同合成条件对THPS产率的影响,并通过正交实验确定最佳合成工艺为:黄磷∶锌粉∶硫酸∶甲醛=1∶2.5∶7.5∶5(摩尔比),反应温度为85℃,反应时间为6 h。建立了测定其活性物含量的离子交换法,测得THPS的含量为79.20%。用36%乙酸对产品进行重结晶,成功得到了THPS针状晶体。     

高含量2，4’-二羟基二苯砜的合成

以邻二氯苯为溶剂，苯酚、硫酸为原料，通过添加催化剂亚磷酸合成2，4＇-二羟基二苯砜（2，4＇-BPS），确定了较好工艺条件：n苯酯：n100%硫酸=2．2：1，亚磷酸16g，回流时间8．0h，2，4＇-BPS含量为47．42％，粗收率为70．0％，产品为白色的结晶。同时还研究了以较便宜二氯甲苯为溶剂合成2，4＇-BPS的工艺条件：n苯酚：n100％硫酸=2．2：1，不加催化剂，反应时间5．0h，二氯甲苯200g，2，4＇-BPS含量为42．21％，粗收率为91．7％，产品为浅粉色结晶。     

高羟甲基含量甲阶酚醛树脂的合成

利用KOH作催化剂,以甲醛和苯酚为原料合成了一种高痉甲基含量的甲阶酚醛树脂,通过羟甲基含量、可被溴化物含量、固有粘度的测定和甲醛转化率的计算,研究了反应条件对合成的影响。结果表明：随着反应温度的升高、甲醛和KOH用量的增加、反应时间的延长,树脂中的羟甲基含量先增加,后减小,树脂的固有粘度则逐渐增大,其中反应温度和催化剂用量的变化树树脂固有粘度的影响较大。在65℃的条件下,n（甲醛）：n (醛酚）：n（氢氧化钾）为2．5：1：0．1时,反应,甲阶酚醛树脂中的羟甲基质量分数可以达到32．8％,固有粘度达到2．68ml.g^-1。并用红外光谱对树脂的结构进行了表征。     

二（二甲苯基）甲烷合成工艺条件优化研究

通过正交试验和梯度寻优试验,找到了二甲苯与甲醛合成二（二甲苯基）甲烷的优化工艺条件：二甲苯与甲醛的摩尔比８：１,硫酸－二甲基苯磺酸催化剂用量１０．０２５％、反应温度１２０￣１４０℃及反应时间１４０ｍｉｎ,在最优工艺条件下,二（二甲苯基）甲烷收率可达７７．３８％。     

相转移催化法合成2，3，5-三氯吡啶的工艺研究

以五氯吡啶和锌粉为原料，在碱性条件下用相转移催化剂催化还原合成2，3，5-三氯吡啶。确定了最优反应条件：反应温度50℃、时间6个小时、NaOH溶液浓度8mol/L、n（锌粉）：n（五氯吡啶）：n（TMAB）=3．5：1：0．05。在此条件下，收率可达73%以上。     

邻苯二甲酸二异辛酯合成中的催化剂研究

以邻苯二甲酸酐和异辛醇为原料，分别选用对甲苯磺酸、硫酸、磷酸、磷钨酸、SO4^2-／TiO2—A1203等催化剂，合成邻苯二甲酸二异辛酯(简称DOP)，得出DOP合成的最佳催化剂为对甲基苯磺酸。最佳反应条件：原料邻苯二甲酸酐与异辛醇的摩尔比为1：2．2，反应温度130℃，反应时间2．5h，催化剂用量为总量的1．0（W），用环己烷作带水剂，邻苯二甲酸酐的转化率96％（W），产品酯含量98％（W），并研究了具有上述相同功能基的高分子催化剂，含磺酸基的高分子和负载三氯化铝的含磺酸基的高分子，邻苯二甲酸酐酯化转化率达80%（W），产品酯含量98％（W）。     

2，2-二羟甲基庚醛的合成工艺研究

以甲醛和新蒸庚醛为原料，经羟醛缩合反应合成了2,2-二羟甲基庚醛（DMH）．羟醛缩合反应的最佳工艺条件为：反应温度为35℃，n（甲醛）：n（庚醛）：n（NaOH）=4：1：1．3。缩合瘌为w（SaOH）=10％溶液，反应时间为5h．加甲酸中和碱-经精制DMH的收率达到67．8％．2,2-二羟甲基庚醛的结构用红外光谱（IR）表征。     

乙醇胺二甲叉膦酸的合成

以乙醇胺、三氯化磷和甲醛为原料合成了乙醇胺二甲叉膦酸（EODMP）。对其合成条件进行了探讨，确定最佳条件为：甲醛过量50％，反应温度为100℃，回流时间3h。在优化上，产品的收率（以乙醇胺计）为91．2％。     

苯酚-尿素-甲醛三元共缩聚树脂合成工艺的研究

针对脲醛树脂在制板过程以及人造板材在使用过程中不断释放甲醛。危害人体健康的环保问题,以及耐水、耐老化性能差的缺点。以苯酚、尿素和甲醛为原料,采用高温（90℃）缩聚反应合成苯酚-尿素-甲醛共缩聚树脂（PUF胶黏剂）,缩短了反应时间,提高了耐水、耐老化性能,且游离甲醛含量〈O．3％,游离苯酚含量〈0．5％。对树脂的结构和性能进行全面的分析,得出当甲醛、尿素、苯酚摩尔比为10：8：1时树脂性能最佳,压制的胶合板力学性能好,板材甲醛释放量达到GB18580—2001中E2级水平。     

2,2-二羟甲基庚醛的合成工艺研究

以甲醛和新蒸庚醛为原料，经羟醛缩合反应合成J，2,2-二羟甲基庚醛（DMH）。羟醛缩合反应的最佳工艺条件为：反应温度35℃，n（甲醛）：n（庚醛）：n（NaOH）=4：1：1．3，缩合剂为WNaOH=10％溶液，反应时间为5h。加甲酸中和碱，经精制DMH的收率达到67．8％。2,2-二羟甲基庚醛的结构用红外光谱（IR）表征。     

Interactions between shrinkage reducing admixtures (SRA) and cement paste's pore solution

Shrinkage reducing admixtures (SRA) have been developed to combat shrinkage cracking in concrete elements. While SRA has been shown to have significant benefits in reducing the magnitude of drying and autogenous shrinkage, it has been reported that SRA may cause a negative side effect as it reduces the rate of cement hydration and strength development in concrete. To examine the influence of SRA on cement hydration, this study explores the interactions between SRA and cement paste's pore solution. It is described that SRA is mainly composed of amphiphilic (i.e., surfactant) molecules that when added to an aqueous solution, accumulate at the solution-air interface and can significantly reduce the interfacial tension. However, these surfactants can also self-aggregate in the bulk solution (i.e., micellation) and this may limit the surface tension reduction capacity of SRA. In synthetic pore solutions, SRA is observed to form an oil-water-surfactant emulsion that may or may not be stable. Specifically, at concentrations above a critical threshold, the mixture of SRA and pore fluid is unstable and can separate into two distinct phases (an SRA-rich phase and an SRA-dilute phase). Further, chemical analysis of extracted pore solutions shows that addition of SRA to the mixing water depresses the dissolution of alkalis in the pore fluid. This results in a pore fluid with lower alkalinity which causes a reduction in the rate of cement hydration. This may explain why concrete containing SRA shows a delayed setting and a slower strength development.     

Influence of bleed water reabsorption on cement paste autogenous deformation

The effects of bleed water reabsorption and subsequent early age expansion on observed autogenous deformation are investigated in this research. Bleeding was induced by varying superplasticizer and shrinkage-reducing admixture dosages and by increasing the water-to-cement ratio. This research revealed that significant early age expansion occurs with increasing chemical admixture dosages and higher water-to-cement ratios, as expected, due to increasing bleeding of those samples. When samples were rotated, negligible early age expansion was observed. Thus, bleed water reabsorption is shown to be the primary mechanism causing initial expansion in sealed autogenous deformation samples. Thermal dilation and ettringite growth appear to have a minimal influence on the observed expansion. Rotating the samples during setting eliminates the potential for bleed water reabsorption and is recommended for all autogenous deformation testing.     

La掺杂(Na0.5Bi0.5)0.82(K0.5Bi0.5)0.18TiO3系统无铅压电陶瓷的制备工艺探讨

采用传统陶瓷工艺，研究了制备[（Na0.5Bi0.5）0.82（K0.5Bi0.5）0.18]1-xLaxTiO3（x=0．00，0．01，0．03，0．05，0．10）无铅压电陶瓷的工艺条件对陶瓷的物相组成、显微结构和压电性能的影响。利用XRD、SEM等技术分析结果表明，合成温度的提高有利于主晶相的形成，且此系统烧成温度范围较窄，故需控制在合适的烧成温度下才能得到高致密度的陶瓷。同时，研究了极化工艺条件对材料压电性能的影响，结果表明，提高极化电场强度、控制适当的极化温度有利于提高材料的压电性能。     

La掺杂(Na_(0.5)Bi_(0.5))_(0.82)(K_(0.5)Bi_(0.5))_(0.18)TiO_3系统无铅压电陶瓷的制备工艺探讨

采用传统陶瓷工艺,研究了制备[(Na0.5Bi0.5)0.82(K0.5Bi0.5)0.18]1-xLaxTiO3(x=0.00,0.01,0.03,0.05,0.10)无铅压电陶瓷的工艺条件对陶瓷的物相组成、显微结构和压电性能的影响。利用XRD、SEM等技术分析结果表明,合成温度的提高有利于主晶相的形成,且此系统烧成温度范围较窄,故需控制在合适的烧成温度下才能得到高致密度的陶瓷。同时,研究了极化工艺条件对材料压电性能的影响,结果表明,提高极化电场强度、控制适当的极化温度有利于提高材料的压电性能。     

Chemical model for cement-based materials: Thermodynamic data assessment for phases other than C-S-H

In the context of waste confinement, concrete may be used both as a confinement and as a building material. Concerning radwaste, the heat released during radioactive decay will modify the equilibrium constants of the minerals forming the concrete. The present work aims to elucidate the temperature dependency of the thermodynamic functions related to minerals from the concrete or associated with some of its degradation products. A large set of experimental data has been collected, for the chemical systems SO₃-Al₂O₃-CaO-CO₂-Cl-H₂O and SiO₂-Al₂O₃-CaO-H₂O, including iron and magnesium bearing phases. Most of the data collected concern experiments in aqueous media but results from calorimetric studies were also included, when available. Based on selected thermodynamic properties for each phase, predominance diagrams were drawn for the chemical elements listed above. Phase relations reported into predominance diagram appear rather consistent with most of the literature results. The case of katoite has been especially discussed, because it shows inconsistencies with respect to a hydrogarnet-grossular solid solution and with respect to phase relations reported into already published works. Finally, we underline the chemical compatibility of Portland cement pastes with carbonate aggregates, compared to silicates, for long-term storage applications.     

An investigation of microstructure evolution in cement paste through setting using ultrasonic and rheological measurements

The response of hydrating cement paste through setting are monitored using rheological measurements and ultrasonic reflection measurements. Increases in the elastic modulus and yield stress of cement paste with time are obtained from the rheological measurements. Ultrasonic measurements are performed using horizontally polarized shear waves (SH) reflected off of the hydrating cement paste. Changes in the ultrasonic signal through setting are related with changes in the porosity and stiffness of an equivalent water-filled poroelastic material, which provides identical acoustic impedance. The measured changes in the shear modulus obtained from ultrasonic measurement are shown to correlate well with increase in elastic modulus obtained from rheological measurements. The increase in the shear modulus of the porous material obtained from the ultrasonic measurements is shown to correspond well with the observed increase in the yield stress of the cement paste. By combining the information from rheological and ultrasonic measurements, it is found that even in the fluid stage there is sufficient structural integrity in the arrangement of cement grains to support low-amplitude shear stress and the evolution of a continuously connected network of cement particles within the paste is coincident with a rapid increase in the shear modulus of the porous skeleton.     

Nonlinear ultrasonic evaluation of load effects on discontinuities in concrete

The presence of discontinuity surfaces in concrete structures, i.e. two or more layers in contact, may be an existing situation with evident relapses on damage formation and progression. Differences occur depending on the type of discontinuity, which could be a thin weaker layer or a pre-existing crack. The behavior of pre-existing interfaces is here studied by means of the Scaling Subtraction Method, a Nonlinear Ultrasonic Non-Destructive Technique, that revealed to be effective in describing the mechanical evolution of concrete samples with discontinuity surfaces under the effects of compressive loads.     

Assessment of the long-term stability of cementitious barriers of radioactive waste repositories by using digital-image-based microstructure generation and reactive transport modelling

Cement-based grout plays a significant role in the design and performance of nuclear waste repositories: used correctly, it can enhance their safety. However, the high water-to-binder ratios, which are required to meet the desired workability and injection ability at early age, lead to high porosity that may affect the durability of this material and undermine its long-term geochemical performance.In this paper, a new methodology is presented in order to help the process of mix design which best meets the compromise between these two conflicting requirements. It involves the combined use of the computer programs CEMHYD3D for the generation of digital-image-based microstructures and CrunchFlow, for the reactive transport calculations affecting the materials so simulated. This approach is exemplified with two grout types, namely, the so-called Standard mix 5/5, used in the upper parts of the structure, and the “low-pH” P308B, to be injected at higher depths.The results of the digital reconstruction of the mineralogical composition of the hardened paste are entirely logical, as the microstructures display high degrees of hydration, large porosities and low or nil contents of aluminium compounds.Diffusion of solutes in the pore solution was considered to be the dominant transport process. A single scenario was studied for both mix designs and their performances were compared. The reactive transport model adequately reproduces the process of decalcification of the C-S-H and the precipitation of calcite, which is corroborated by empirical observations. It was found that the evolution of the deterioration process is sensitive to the chemical composition of groundwater, its effects being more severe when grout is set under continuous exposure to poorly mineralized groundwater. Results obtained appear to indicate that a correct conceptualization of the problem was accomplished and support the assumption that, in absence of more reliable empirical data, it might constitute a useful tool to estimate the durability of cement-based structures.     

Wavelet-based analysis of ultrasonic longitudinal and transverse pulses in cement-based materials

Ultrasonic pulse velocity has been used for decades to detect localized damage and to estimate concrete properties. More recent applications aim at diffuse damage characterization, such as environmental and mechanical damage. In most applications the methodology to calculate pulse speed is a very important issue. This work, applying continuous wavelet transform (CWT) to construct time-frequency signal representations, calculates frequency-dependent velocity of longitudinal and transverse ultrasonic pulses using wavelet scales. The method is applied to a total of 14 specimens of 5 different mixes and frequency-dependent velocities are calculated using four wavelet families. The CWT capability to decompose the inquiring pulse spectrum and analyze phase velocities is discussed with regard to wavelet, pulse type, and mixture. Frequency-dependent velocity of longitudinal pulses at lower frequencies (from 100 kHz up to 250 kHz) was proven to be much more sensitive to mix proportions than transverse pulses.