改造对沸石基复合环境材料表面结构的影响及应用

以天然斜发沸石为研究对象,采用不同改造方法对其进行改造,研究发现LaCl3化学改造2h,500℃高温下焙烧1h后所得沸石基复合环境材料去除污水中磷的性能有了较大提高。SEM和EDS测试材料的结果表明,天然沸石改造后其表面形貌发生了改变,孔结构得到了扩展,改造前后材料主要成分均为Si、Al、O,但改造后材料中La离子含量明显增加。材料表面结构测试分析发现,改造后复合材料孔道得到拓宽,孔径分布更为均匀,孔容积、比表面积、孔径数量和孔隙率与沸石原材料相比均有所增加。在此基础上,研究了沸石基复合环境材料用量、处理时间及废水pH值对材料除磷效果的影响,结果表明,材料在用量1.2g/L、处理时间3h、pH值3～7的条件下,对废水中磷去除率可达98.46%。     

表面活化沸石外比表面积的试验研究

利用阳离子表面活化剂(HDTMA Cl)对天然沸石进行了表面活化改性,并使用BET法测定了表面活化沸石颗粒(SMZ)和天然沸石颗粒的外比表面积,试验结果表明,粒径为4～100目时,天然沸石的比表面积为13.44～14.32m2/g,活化沸石的比表面积为4.18～6.79m2/g,与天然沸石相比较,其值要小1～2倍。通过轻拍式原子力显微镜镜像分析(TMAFM),探讨了SMZ外比表面积发生变化的原因。     

柠檬酸钠改性对沸石吸附水中低浓度碳、氮污染物的影响研究

研究了柠檬酸钠改性沸石后其吸附水中低浓度氨氮、硝态氮、COD等污染物的效果和吸附热力学、动力学特征,并通过比表面积与孔径分布测试、扫描电镜、X射线衍射手段测试分析了柠檬酸钠改性对沸石结构特征的影响结果。结果发现,天然沸石经柠檬酸钠改性后,其同步吸附3种污染物的效果有较大提高,其中对氨氮的去除率由53%上升到92%。对硝态氮的去除率由2%提升到10%、对COD的去除率由5%提高到35%。柠檬酸钠改性沸石后其对氨氮及COD的吸附符合Langmuir等温线,属于单层覆盖,而对硝态氮的吸附更符合Freundlich等温线。叶洛维奇吸附动力学方程在描述沸石吸附氨氮、硝态氮和COD的吸附动力学上,更具有优越性,说明沸石对3种污染物的吸附均属于化学吸附。测试分析发现,柠檬酸钠改性沸石后其组分中钠元素含量增加,表面变得比较光滑、孔径和孔体积增大,但柠檬酸钠改性并没有改变沸石的晶体结构,主要是因为引入了钠离子以及柠檬酸根的酸性作用,提高了沸石的吸附能力。     

MnOx改性的斜发沸石及其在油墨废水净化中的应用

目的 研究一种具备吸附和降解作用的催化剂,进而更高效地净化处理油墨废水。方法 通过氧化还原沉淀法对天然斜发沸石进行MnOx改性,并研究天然斜发沸石和MnOx改性的斜发沸石对油墨废水进行净化处理。考察MnOx改性斜发沸石的晶型、孔结构和形貌,系统地研究处理时间和处理温度对油墨废水COD和色度去除率的影响规律。结果 MnOx改性的斜发沸石保持了斜发沸石的晶型结构和形貌,具有更高的比表面积、孔容量,以及更宽的孔径分布。结论 在最佳的处理条件下,与天然斜发沸石相比,MnOx改性斜发沸石具有更高的去除性能,在20 ℃下对油墨废水处理15 min,其COD和色度去除率分别可以达到98%和99%以上。     

氨基改性天然沸石的制备及其对Ni~(2+)的吸附行为

根据软硬酸碱原理,在天然沸石表面嫁接上能与金属镍离子发生化学配位作用的氨基基团,制备了氨基改性的天然沸石.用X射线衍射和红外光谱技术对改性前后天然沸石的结构和表面性质进行了表征;研究了氨基改性天然沸石对镍离子的吸附行为.结果表明:氨基改性后的天然沸石仍然保持原来的结构,在其表面嫁接上了氨基基团;氨基改性天然沸石能对镍离子发生快速吸附作用并具有很大的吸附效率和吸附容量;镍离子浓度在60 mg/L时,氨基改性天然沸石在30 min即迅速达到吸附平衡,吸附效果(吸附效率98.6%,吸附容量5.92 mg/g)显著高于未改性的天然沸石;当镍离子浓度高达150 mg/L时,改性天然沸石也有很好的吸附效果.     

改性麦饭石吸附除磷性能研究

采用硝酸铁对麦饭石进行改性,考察了改性麦饭石投加量、pH、吸附时间和吸附温度对磷吸附效果的影响。对其吸附等温曲线进行了分析,并通过扫描电镜、比表面积、X射线衍射和红外光谱等表征方法对改性麦饭石的结构进行了探究。结果表明:0.8g改性麦饭石对50mL 5mg/L(总磷质量浓度)废水中磷的去除率高达98%以上,去除效果远远优于天然麦饭石;Freundlich吸附等温方程能更好地描述改性麦饭石对磷的吸附行为;并且该改性方法显著增大了麦饭石的比表面积及总孔体积,废水中的磷有效地附着在改性麦饭石上。     

天然斜发沸石的改性及其对海水中K~+吸附交换容量的研究

为提高天然斜发沸石对海水中K+的吸附交换容量,对天然沸石进行了电炉、微波和超声波加热物理改性以及微波化学改性研究。重点考察了不同微波功率和处理时间时盐改性以及不同微波化学改性条件下所得沸石对海水中K+的吸附交换容量,同时对不同改性沸石的晶体结构进行了XRD表征。结果表明,天然斜发沸石经微波盐改性后对海水中K+的吸附交换容量有所提高,并随微波处理功率的增加和时间的延长而增大;经微波化学改性后吸附交换容量显著提高,可达0.71mmol/g;各种改性方式未对沸石的结构构成破坏,所得改性沸石的晶体结构基本相似。     

沸石颗粒表面电位调控、结构表征及应用

以天然斜发沸石为研究对象,采用不同浓度的AlCl3和LaCl3对其进行调控。重点研究了调控沸石表面zeta电位与去除再生水中磷酸盐性能之间的关系。并运用SEM-EDS、XRD、比表面积与孔径分析等手段对经氯化镧调控后的沸石进行结构表征。结果表明,天然沸石经5g/L AlCl3、4g/L LaCl3、1g/L AlCl3与3g/L LaCl3组合3种药剂调控处理后,颗粒表面zeta电位由未调控前的-37.80mV分别变为-33.33、-20.69、-30.96mV,再生水中磷酸盐的去除率由7.26%分别提高到12.55%、92.81%和55.56%;说明AlCl3和LaCl3调控后,沸石颗粒表面正电荷增多,表面zeta正电位增大,除磷性能也不同程度提高,且调控沸石除磷性能与zeta电位变化成正相关。经氯化镧调控后的沸石,形成了很多珊瑚状的表面结构,同时出现了较多微孔,比表面积与孔径分布也发生了很大变化。     

Cu~(2+)-ZnO/十六烷基吡啶-蒙脱石复合抗菌材料的制备与表征

以蒙脱石、Cu2+、Zn2+、十六烷基吡啶(CP)等为主要原料,制备Cu2+-ZnO/十六烷基吡啶-蒙脱石(CZCM)复合抗菌材料,并对其结构、表面特性和抗菌活性进行表征。结果表明,在蒙脱石悬浮液中,Zn2+按蒙脱石离子交换容量(CEC)摩尔比0.75倍的量加入,经搅拌、碱沉淀、煅烧、粉碎,加水悬浮后,再按蒙脱石CEC的0.75和0.4倍量分别加入Cu2+和CP,可制得Cu2+、ZnO和CP含量分别为3.04%、3.71%和6.62%的CZCM抗菌材料。与蒙脱石相比,CZCM的层间距和孔径增大;CEC、比表面积、微孔比表面积和微孔体积缩小;外比表面积和孔体积增大;总电荷、层间电荷和端面电荷的绝对值下降;Zeta电位升高。抗菌活性测定数据显示:CZCM对病原大肠杆菌和鼠伤寒沙门氏菌均有较强的抗菌活性。     

聚四氟乙烯(PTFE)纤维协同磁性沸石脱除烟气Hg~0的实验研究

通过溶胶-凝胶过程,在经过有机改性的可再生载银磁性沸石的磁颗粒表面形成介孔硅涂层(以防止磁性粒子被氧化或在酸性环境中被腐蚀)。用元素分析、BET比表面积测定、X射线衍射分析等对吸附剂进行了表征。用浸渍法将聚四氟乙烯(PTFE)滤袋纤维和可再生载银磁性沸石制成复合吸附剂,并对其用浓度分别为5%(wt,质量分数,下同)、10%、15%的HNO_3溶液进行改性。在汞固定床实验台上进行了该复合吸附剂改性前后吸附单质汞的测试,实验结果表明,在汞蒸气入口浓度为45μg/m3,吸附温度为160℃,磁性沸石与PTFE纤维的质量比为2∶1时,对Hg~0脱除效率最高,可达76.5%,经过5%、10%的HNO_3改性后的吸附剂分别比未改性前脱汞率提高了4%、9%,而经过15%的HNO_3溶液改性后,吸附剂脱汞效率降低。     

L-丙氨酸掺杂下KDP晶体成核特性及生长实验研究

通过实验测定了L-丙氨酸掺杂下KDP溶液的亚稳区和诱导期,根据经典成核理论计算了晶体成核的热力学和动力学参数,分析了L-丙氨酸对KDP溶液成核特性的影响。结果表明,随着掺入的L-丙氨酸浓度的增大,KDP的溶解度减小,亚稳区变宽,诱导期变长,溶液更加稳定。采用吊晶法进行了KDP晶体生长实验,发现其(100)面法向生长速度随掺杂浓度增大而减小,在过饱和度σ>0.04时,晶体(100)面的生长以二维成核生长机制为主。     

Measurement of the tunnel rate in SIS' tunnel junctions as function of bias voltage

Cryogenic detectors with superconducting tunnel junctions can provide an energy resolution improved by at least one order of magnitude compared with standard semiconductor detectors. While the detection principle was already demonstrated many years ago, the past years were dedicated to the transition from the laboratory sample to practical detectors. Our most favored detector design gives rise to tunnel junctions with electrodes of unequal energy gaps. In such hetero tunnel junctions bias conditions can be established which cause a negative signal current. We report the experimental verification of this effect, and we discuss the yield of charge signal of cryogenic detectors based upon superconducting tunnel junctions.     

Modeling injury rates as a function of industrialized versus on-site construction techniques

It is often predicted that the industrialization of building activities will lead to a reduction of accident rates in the construction sector, particularly as a result of switching activities from building sites to factories. However, to date no scientific research has provided objective quantitative results to back up this claim. The aim of this paper is to evaluate how industrialization affects the accident rate in different industrialized building systems in Spain. Our results revealed that the industrialized steel modular system presents the lowest accident rate, while the highest accident rate was recorded in the construction method with cast-in-place concrete. The lightweight construction system also presents a high accident rate. Accordingly, industrialized building systems cannot claim to be safer than traditional ones. The different types of “on-site work” seem to be the main variable which would explain the accident rates recorded in industrialized construction systems.     

In Vivo and In Vitro Degradation Behavior of Magnesium Alloys as Biomaterials

The corrosion behavior of pure Mg,AZ31,and AZ91D were evaluated in various in vitro and in vivo environments to investigate the potential application of these metals as biodegradable implant materials.DC polarization tests and immersion tests were performed in different simulated body solutions,such as distilled(DI) water,simulated body fluid(SBF) and phosphate buffered solution(PBS).Mg/Mg alloys were also implanted in different places in a mouse for in vivo weight loss and biocompatibility investigations.The in vivo subcutis bio-corrosion rate was lower than the corrosion rate for all of the in vitro simulated corrosive environments.The Mg/Mg alloys were biocompatible based on histology results for the liver,heart,kidney,skin and lung of the mouse during the two months implantation.Optical microscopy and scanning electron microscopy were carried out to investigate the morphology and topography of Mg/Mg alloys after immersion testing and implantation to understand the corrosion mechanisms.     

Mechanical behavior and deformation micromechanisms of polypropylene nonwoven fabrics as a function of temperature and strain rate

The mechanical behavior and the deformation and failure micromechanisms of a thermally-bonded polypropylene nonwoven fabric were studied as a function of temperature and strain rate. Mechanical tests were carried out from 248 K (below the glass transition temperature) up to 383 K at strain rates in the range ≈10⁻³ s⁻¹ to 10⁻¹ s⁻¹. In addition, individual fibers extracted from the nonwoven fabric were tested under the same conditions. Micromechanisms of deformation and failure at the fiber level were ascertained by means of mechanical tests within the scanning electron microscope while the strain distribution at the macroscopic level upon loading was determined by means of digital image correlation. It was found that the nonwoven behavior was mainly controlled by the properties of the fibers and of the interfiber bonds. Fiber properties determined the nonlinear behavior before the peak load while the interfiber bonds controlled the localization of damage after the peak load. The influence of these properties on the strength, ductility and energy absorbed during deformation is discussed from the experimental observations.     

再生丝素蛋白膜的性能及其细胞培养特性研究

研究了温度梯度法所制再生丝素蛋白膜的溶失率、抗酶能力和动物细胞体外培养特性。以紫外分光光度法检测丝素蛋白膜在水中的溶失率;再用质量体积浓度0.25%和0.5%的胰蛋白酶液分别消化丝素蛋白膜2d,以膜的结构和质量是否发生明显变化为指标,判断膜抗胰蛋白酶的能力;最后在丝素蛋白膜上培养BHK-21细胞和Vero细胞,再用0.25%和0.5%胰蛋白酶液分别消化膜上细胞并进行传代培养,观察细胞形态和生长状况。实验结果表明,温度梯度法直接所制丝素蛋白膜48h内的溶失率低于0.2%,再经25%甲醇处理后溶失率为0,2d内膜仍保持完整结构且质量无明显变化;BHK-21细胞和Vero细胞在丝素蛋白膜上生长良好,形态正常;0.25%和0.5%的胰蛋白酶液均可在4min内将膜上两种细胞消化脱落且细胞连续传代培养5代,细胞形态正常。     

Intrinsic ductility for structural materials as a function of stress and temperature

Abstract

In recent years, a method has been developed to measure current creep strength at nearly constant structure in a high precision stress relaxation test (SRT), covering at least five decades in creep rate in a one day test. Results have been reported on a wide range of metallic alloys, polymers, composites and ceramics. In the present paper it is shown that these same data can be used to determine a measure of intrinsic ductility over the same range of stress, using results on a low alloy Cr–Mo–V steel. This is based on an experimental and theoretical correlation between elongation at failure and strain rate sensitivity, m. This refined SRT test can now be used to evaluate both the intrinsic creep strength and the intrinsic ductility as a function of stress in a single short-time test. The test can detect embrittling phenomena at very low creep rates as a function of temperature. This measure of ductility may be used directly in engineering design and remaining life assessment.     

The preparation and evaluation of salt forms of linogliride with reduced solubilities as candidates for extended release

Salts of linogliride with reduced solubilities were prepared and evaluated as potential candidates for extended-release oral dosage forms. A once-daily dose of 300–800?mg was intended. Seven acids were selected: p-acetamidobenzoic, benzoic, p-hydroxybenzoic, 3-hydroxy-2-naphthoic, 1-napsylic, pamoic, and p-toluenesulfonic acids but only four salts were able to be prepared in suitable quantities for evaluation: linogliride pamoate, p-hydroxybenzoate, 3-hydroxy-2-naphthoate, and 1-napsylate. The pH-solubility profiles of the four new salts, free base, and fumarate salt were compared over the pH 1.43–8.3 range and the intrinsic dissolution rates of the four new salts and the free base were determined at pH 1.43, 4.4, and 7.5. The range of the pH-solubility profile and intrinsic dissolution rates of the p-hydroxybenzoate salt were less than the free base and fumarate and higher than the other three new salts. The pH-solubilities and intrinsic dissolution rates of the 1-napsylate salt were pH-independent. The solubilities and intrinsic dissolution rates of the pamoate and 3-hydroxy-2-naphthoate were higher at pH 1.4–3.4 than at higher pH. At pH 4.4 and higher, the solubilities were essentially the same, in the 1–2?mg/mL range. The intrinsic dissolution rates were also very low and not very different. Dissolution studies with capsules containing 800?mg doses of the pamoate, 1-napsylate, free base, and fumarate performed in a dissolution medium of pH beginning at 2.2 and ending at 6.8 demonstrated that the pamoate and 1-napsylate salt forms dissolved slower and could be useful as extended-release forms.     

酚醛树脂为前驱体制备多孔碳泡沫材料

以液态酚醛树脂为前驱体,正戊烷为发泡剂,吐温80为匀泡剂,在高压釜中通过卸压发泡的方法制备了酚醛树脂泡沫,然后将其经1000℃碳化后得到碳泡沫.研究结果表明,所得的典型碳泡沫样品是一种以无定形碳结构为主的轻质多孔碳材料,密度约为0.15g/cm3.碳泡沫的微结构可以通过调节卸压速率而得到有效控制,当卸压速率为0.05MPa/min时,可以得到孔洞相互贯穿、平均孔径约为300μm且分布较为均匀、接点完好,韧带光滑的多孔碳泡沫.     

Significance and influence of the ambient temperature as a rate factor of steel reinforcement corrosion

The rate of corrosion of reinforcement being an electrochemical process, undoubtedly is dependent even on the level of the ambient temperature. Therefore, the ambient temperature seems to be an important factor of the corrosion rate and the durability of the reinforced concrete structures in aggressive environment. The present data on the influence and significance of the ambient temperature in the process of corrosion of reinforcement of the reinforced structures are surprisingly limited and poor. It seems that it is supposed to be a simple increase of corrosion rate when the ambient temperature is increased. The lack of information was a motivation for the present study. It was aimed at the experimental research of the influence of the increase of the ambient temperature on the rate of chloride induced corrosion of steel reinforcement. The results obtained show that the influence of the studied factor is more complex showing an acceleration effect till a temperature of 40°C diversified by the inhibition effects with further increase of the ambient temperature.