海水环境粉煤灰混凝土结构耐久性现场检测与评估分析

对服役12年的华南某跨海大桥典型构件开展碳化性能、氯离子扩散性能等指标的耐久性检测,评估了海水环境下掺粉煤灰的高性能混凝土长期耐久性。研究表明:随高程的增加混凝土碳化深度逐渐增大,其中大气区浪溅区水位变动区,碳化作用对粉煤灰混凝土结构耐久性的影响较小;粉煤灰可显著提升实体结构混凝土抗氯离子侵蚀性能,粉煤灰高性能混凝土的氯离子扩散系数不大于0.40×10-12m2/s,比普通混凝土氯离子扩散系数降低了约6倍;利用规范计算了引桥承台混凝土中氯离子含量计算值,其计算值与实测值吻合较好,可用于实体工程混凝土结构的耐久性评估,评估结果显示采用粉煤灰高性能的桥梁典型构件满足100年设计使用寿命的要求。     

改性粉煤灰性质及其封堵油层大孔道效果

粉煤灰是燃煤火力发电厂的废弃物,由大小不等、结构疏松的非晶质玻璃相球形颗粒组成,其主要化学成分是铝硅酸盐,具有来源广和成本低等特点。在水热条件下,Holler和Wirsching首先利用粉煤灰与碱（NaOH或KOH）作用合成了沸石。针对油田封堵油层孔隙即改善注水井吸水效果的实际需求,在总结和吸取粉煤灰和沸石颗粒封堵油层孔隙矿场施工成功经验和不足基础上,探索了水热条件下粉煤灰部分转化为沸石的配方组成和工艺条件,研究了改性粉煤灰组成和外观结构特征,评价了改性粉煤灰的封堵效果,分析了改性粉煤灰封堵作用机理。研究结果对改善油层孔隙封堵效果、提高油田注水效率具有重要应用价值。     

Properties and performance of a high volume fly ash grout

Abstract

This study investigated the penetrability of high volume fly ash cement suspensions prepared with and without superplasticizer into sandy soil having different relative densities with 30%, 60%, 73%, and 83% through permeation grouting. Class C fly ash was used due to its pozzolanic activity and fineness. Due to engineering characteristics and cost, cementitious grouts are the most commonly used grout in both waterproofing and ground strengthening. Fly ash-cement grouts have relatively constant and low viscosity values for a reasonable period after preparation, exhibit limited or negligible bleed capacity and set and develop satisfactory strength within a relatively short period. Modeling of grouting of soil was done in laboratory and improvements in physical and mechanical properties of grouted soil were analyzed. Unconfined compressive strength, shear strength and permeability characteristics of grouted soil were studied as a result. Unconfined compressive strength values of grouted sand with high volume fly ash ranged between 410 and 1107?kPa. Morover, cohesion values were comparable to microfine cement grouting ranging from 373 to 511?kPa. Furthermore, permeability values were also approximately equal to the permeability of impervious liners, which is around 1?×?10^?7?cm/s. The findings support the applicability of grouting in different applications.     

海洋环境下粉煤灰混凝土的抗冻性与抗氯离子渗透性的耦合

针对海洋环境条件,重点研究了粉煤灰混凝土的抗冻性和氯离子渗透性能的相互关系.试验分别研究了水胶比、粉煤灰等量取代水泥掺量大小、引气剂掺量等因素对抗冻性和抗氯离子渗透性能的影响,并与普通混凝土进行了对比.结果表明,粉煤灰不增加混凝土的抗海水冻融耐久性;粉煤灰增加混凝土的抗氯离子渗透性能,但是掺量超过30%,抗氯离子渗透性能下降;粉煤灰对混凝土抗冻性和抗氯离子渗透性的耦合影响在30%左右存在一个最佳掺量.为评估混凝土的抗冻性和氯离子扩散性的耦合性能,提出了新的评价方法--冻渗比(R值方法),并进行了试验验证.SEM和MIP微观分析与R值方法评价的结果是吻合的.     

海水为溶剂合成纳米粉煤灰沸石及其性能表征

以海水为溶剂,采用熔融法合成了纳米粉煤灰沸石。粉煤灰与NaOH的质量比为1:1.2,熔融温度550℃,熟料质量与海水固液的体积比为1:5(g/mL),晶化温度100℃,晶化时间6h。通过仪器分析和化学方法,对产物的结构、形貌、性能进行表征。同时,研究了产物的矿物组成、形貌、比表面积、阳离子交换量及化学组成。结果表明:产物为NaX型沸石和羟基方钠石的复合型沸石,海水晶化粉煤灰通过碱熔融法得到沸石质量优于传统水热法。合成沸石的性能和各项应用指标表明,所合成的沸石具有良好的实际应用价值。     

Effect of slow-solvent-vapour treatment on performance of polymer photovoltaic devices

In this work, enhanced poly(3-hexylthiophene):[6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PCBM) bulk-heterojunction photovoltaic devices are achieved via slow-solvent-vapour treatment. The correlations between the morphology of the active layer and the photovoltaic performance of polymer-based solar cell are investigated. The active layers are characterized by atomic force microscopy and optical absorption. The results show that slow-solvent-vapour treatment can induce P3HT self-organization into an ordered structure, leading to the enhanced absorption and efficient charge transport.     

Effect of Fly Ash on Frost-Resistance and Chloride Ions Diffusion Properties of Marine Concrete

It is necessary to pay more attention to the durability of concrete undergoing freeze-thaw cycles and seawater attack simultaneously.Investigated are the effects of water-binder ratio,fly ash (FA) contents and air-entraining agent on resistance to frost and chloride diffusion of marine concrete blended with FA in natural seawater.The results show that fly ash does not improve the frost resistance of concrete but can improve its resistance to chloride diffusion by addition of less than 30%.The resistance to frost and chloride diffusion of FA concrete can be improved with the decrease of water-binder ratio,and FA may improve both of them simultaneously only being mixed with air-entraining agent.A ratio (named as R) of the frost-resisting durability factor to chloride diffusion coefficient can be used to evaluate the durability of marine concrete.Scanning electron microscope (SEM) analyses are consistent with the evaluations by the value of R.     

海上油田注聚合物时机研究及现场应用

海上油田开发受到平台寿命的限制,为了在有限的平台寿命期内尽可能多的采出原油,对合理注聚合物时机的研究非常必要。利用平面物理模型实验以及数值模拟方法对不同注聚合物时机的聚合物驱油效果进行了研究。物理模型实验研究结果显示,对于生产时间足够长的油田,不同时机注聚合物,其最终采收率以及聚合物驱与水驱相比采收率增幅的差别不大,而对于生产时间有限的油田,应适当提早注聚合物。数值模拟研究结果显示,海上油田早期注聚合物能够获得更高的采收率增幅、吨聚合物增油及收益。基于实验及数值模拟研究结论及认识,在A油田A井组开展了早期注聚合物现场试验,并取得了初步成效。     

Effects of fly ash and slag content on the solidification of river-dredged sludge

Abstract

River-dredged sludge has a high water content and minimal bearing capacity and strength. Adding cement, fly ash, and slag to dredged sludge as a combined curing agent can quickly reduce its water content and improve its strength. This study experimentally investigates the solidification effectiveness of different proportions of curing agents using methods including electron microscopy, particle size analysis, water ratio limit, and water content and direct shear tests. The water content and shear strength of different combined curing agents are obtained at different ages. We find that an optimum curing agent combination exists. With increases in fly ash and slag content, test results indicate that the water content of solidified sludge first decreases and then increases, whereas the shear strength first increases and then decreases, allowing an optimal combination curing agent to be obtained. When using industrial waste residue as curing agent, it is necessary to consider the negative effects of the curing agent to better control the dosage so as to achieve better curing effect.     

Evaluation of the Effect of Penetration Ratios on Composite Grounds Improved with Sand Compaction Piles

In this paper, centrifuge model tests were conducted in order to understand the deformation characteristics and behavior of sand compaction piles (SCPs) reinforced grounds in relation to area replacement ratios and penetration ratios. To simulate ground stress conditions, preliminary compaction was conducted to form grounds that maintained a certain level of strength. SCPs were installed in the grounds using compaction methods, and the relationship between loads and settlement as well as stress under rigid loading conditions were compared and analyzed. In addition, finite element analyses were conducted in order to verify the results of the centrifuge model tests and assess the effects of penetration ratios and depths on variations in stress. According to the results of the analyses, stress concentration ratios gradually decreased as depths increased, and the decreasing rate increased as penetration ratios decreased. However, in regions close to the surface layer in depth in which SCPs were installed, stress concentration ratios showed almost the same range regardless of penetration ratios. Stress concentration ratios showed proportional relations with penetration ratios. However, they showed similar values in regions close in depth to the surface of the ground. In particular, they showed very close ranges at penetration ratios of 100% and 80%.     

含聚污水水质变化规律及储层伤害机理研究

含聚污水的水质问题是目前聚驱注水油田最紧迫的问题之一,以渤海旅大10-1油田含聚污水为例,利用原子力显微镜、环境扫描电镜等微观分析手段,实验研究含聚污水中残余聚合物对悬浮物浓度和粒径中值,含油率以及结垢离子浓度的具体影响,并进行了含聚污水回注储层岩心动态损害实验。研究表明：当残余聚合物浓度由0 mg/L时逐级增加到150 mg/L时,注入水悬浮物浓度增加了近269.0%,粒径中值仅增加0.3μm,抽滤速度下降了99.3%,含油率下降了86.5%,镁钙离子浓度下降了18.0%。残余聚合物的絮凝作用以及对纤维滤膜的吸附作用是悬浮物增加、抽滤速度显著降低的主要原因,乳化作用使得常规含油率测定值偏低,且残余聚合物浓度及分子量越高,注入水水质变化趋势越明显。另外,单一残余聚合物对高渗透储层损害有限,其与悬浮物及含油的协同作用是主要伤害源。     

双包层多芯光子晶体光纤自相干合成的数值分析与实验

依据耦合模理论分析了双包层多芯光子晶体光纤的超模模场特性,通过倏逝波对7束光的相位调节,可实现相干合成,激光亮度得到很大提高.利用相干合成原理对双包层多芯光子晶体光纤的出射光相干功率密度进行了分析与测量,对此种结构的光子晶体光纤实现自相干合成提出了理论和实验依据.     

壳聚糖的磺化产物对大鼠血栓和凝血时间的影响

甲壳质及壳聚糖的硫酸酯化反应是其化学修饰中最吸引人的研究内容之一。由于它们与肝素有相似骨架， 经硫酸酯化，引入-NHSO3H， - CH2OSO3H - OSO3H， COOH，-CH2COOH基团后得到甲壳质(壳聚糖)类肝素药物，显示出抗栓、抗凝血性能(李鹏程等，1998；曾宪放等，1992；Proeyanat et al.，2002)；如Muzzarelli(1985)早已预见并证实其抗凝血活性；莫斯科血液研究中心病理药理系止血组的研究人员也证明了壳聚糖硫酸酯具有抗凝血活性，他们将肝素与壳聚糖硫酸酯以1∶1的比例给家兔静脉注射各0.5mg/kg，与单纯用肝素1mg/kg对照组比较，其抗凝血效应基本接近，但对照组有出血副作用，而试验组无副作用，可以证明壳聚糖硫酸酯具有既抗凝血又止血的双重调节作用；Tokura等(1994)证实分子质量大小和脱乙酰度不同对磺化产物的抗凝血活力有影响，样品分子质量26000 Da的活性最高，脱乙酰度70%比45%的抗凝血活性更强，脱乙酰度为95%的壳聚糖磺化后抗凝血活性最弱。在中国这方面的研究相对较少，特别是分子中含硫的多寡对生物活性的影响还未见报道。本文作者就壳聚糖的磺化产物对大鼠抗栓、抗凝血进行了研究，表明壳聚糖硫酸酯具有一定的抗栓、抗凝血效果，且具有一定的量效关系，这对今后该方面的进一步研究提供了科学理论依据。     

Effects of frequency and cyclic stress ratio on creep behavior of clay under cyclic loading

The mechanical behavior of clay subjected to cyclic loading is important to consider in the design of the foundations of many types of structures that must resist cyclic loading, such as subgrades and offshore foundations, because clay undergoes greater settlement under cyclic loading than under static loading. The difference in settlement between these two loading patterns due to creep behavior is affected by the cyclic frequency and the cyclic stress ratio. This study investigated the effects of the frequency and cyclic stress ratio of cyclic loading on the creep behavior of a natural clay in China using stress-controlled triaxial tests. The assessed the following parameters: three frequencies, four cyclic stress ratios, and six vertical stresses. The test results indicate that the soft clay displays accelerated creep behavior under dynamic loads. A specific “limit frequency” (in this case, 0.2 Hz) and a “safe load” at which the strain of the soft clay increases very slowly were observed. The effect of the effective axial stress on the creep behavior increases with the increase in the cyclic stress ratio. Based on the tests, the critical cyclic stress ratio is 0.267 at a certain effective axial stress and frequency.     

十二烷基硫酸钠对卤虫生长和发育的影响

以卤虫初孵幼体为试验材料,研究了十二烷基硫酸钠(SDS)对其生长和发育的影响。96h试验期间内测得的结果显示,SDS在24h,48h,72h及96h对卤虫生长的无可见影响浓度(NOEC)分别为11.4,8.7,<8.7,<8.7mg/L;对卤虫发育的无可见影响浓度分别为19.2,19.2,<8.7,<8.7mg/L;SDS可以抑制卤虫胸部分节及胸肢的分化,但不影响复眼的形成。试验结果表明,卤虫生长指标较发育指标敏感,可以将其作为毒性检验的观测指标。     

盐度对香螺行为、鳃和肾抗氧化酶活性与组织结构的影响

为明确不同盐度胁迫下香螺的生理生态学响应及其适应机制,本文采用行为学、组织学和生物化学手段研究了不同盐度条件下(16、20、24、28、32、36、40、44、48)香螺的行为、病理损伤以及抗氧化酶活性。结果显示,在高盐和低盐胁迫下,香螺出现应激反应,摄食率下降,死亡率升高。随盐度升高,香螺的总抗氧化能力先升高后降低,在盐度32时达到峰值;香螺鳃的过氧化氢酶(CAT)活力和超氧化物歧化酶(SOD)活力呈先降低后升高的趋势;肾的CAT和SOD活力呈先升高后降低的趋势。组织切片结果显示,在高盐和低盐胁迫下,香螺嗅检器和鳃丝的形态呈现显著变化,黏液细胞数量均增加。上述结果表明,盐度显著影响香螺的生理生态反应,且香螺可通过行为变化、调节抗氧化酶以及改变组织形态结构从而适应外界盐度的变化。     

Effect of reciprocating and unidirectional airflow on primary conversion of a pentagonal Backward Bent Duct Buoy

An Oscillating Water Column (OWC) device can output energy through reciprocating or unidirectional airflow. The unidirectional airflow is helpful to utilize a simple and high-efficiency unidirectional air turbine. The pentagonal BBDB proposed by us based on OWC principle can be regarded as a floating Oscillating Body and its Power Take-Off (PTO) consists of a chamber, a water column, a turbine and a generator. The Capture Width Ratio (CWR) of the pentagonal BBDB model with the reciprocating and unidirectional airflow was studied in this paper. The wave flume test results indicate the mean CWR of the pentagonal BBDB model with reciprocating airflow can reach up to 121.91% and the mean CWR of the model with unidirectional airflow could reach 100.94% during the whole wave cycle in regular waves. For irregular waves, the mean CWR of the model with the unidirectional airflow is as high as 62.83% during the whole wave cycle. Hopefully, the combination of the pentagonal BBDB with the check valve to output power during the air exhalation and conventional high-efficiency unidirectional turbine will improve the total efficiency of the BBDB.