石门电厂灰场土工布反滤试验及渗流场计算

通过对土工布垂直渗透试验和反滤试验，了解不同规格的土工布在垂向水流作用下的渗透性，并判断土工布作为粉煤灰滤层时是否会产生淤堵。为进一步优化坝型，保证灰场的安全、经济运行、节约投资，利用有限元方法计算灰坝二维渗流场，并对结果进行分析，确定最优灰坝的筑坝方案。     

土石坝应急溢洪道构建材料水力特性研究

采用土工合成材料构建应急溢洪道,可有效防止土石坝发生漫顶溃决。通过建立水槽模型,研究了三种土工合成材料的水力特性,获得了其表面水深、流速、切应力及摩阻系数等参数的变化规律,分析了土工合成材料作为应急溢洪道构建材料的受力特性。结果表明,三种土工合成材料均可用于构建应急溢洪道,其中以300g/m2土工布为最优。     

基于三轴试验的土工布加筋粗颗粒土变形及强度分析

对土工布加筋粗颗粒土做了常规三轴固结排水剪切试验,探讨了试样加筋层数(筋数n)对粗颗粒土变形强度特性的影响。结果表明,加筋后,土体由软化型转为硬化型;加筋可减弱土体剪胀性,限制其侧向变形;各围压下,强度加筋效果系数Rσ均大于1,n平均每增加1,Rσ增加0.075~0.345;加筋土在低围压下加筋效果更显著;筋材通过限制土体的侧向变形提高其强度;加筋土仍符合Mohr-Coulomb破坏准则,加筋后土体内摩擦角基本不变,而粘聚力得到显著提高。     

平板式太阳能光催化净水器对苯酚的降解

以解决西部干旱地区集雨水深度净化为目的,研制了一款平板式太阳能光催化集雨水净水器;以低温水热法在土工布上负载光催化剂,以苯酚为模拟污染物,分别在室内不同条件下及在太阳光下进行光催化氧化实验。结果表明,以自来水(pH=7.2)配制的浓度为2.5mg/L的苯酚、在流量为5.0L/h、光强为1.5mW/cm2的条件下,出水口苯酚的降解率可达52.35%;而在夏季太阳光的照射下,苯酚的降解率可达82.56%;对会宁农村集雨水中挥发酚降解作用明显,出水口挥发酚指标完全达标。     

美对华新能源政策启动调查为哪般?

<正>山姆大叔总是在其国内政治经济出现状况时祭出其贸易保护的大旗,在战争、危机、选举等来临的时候,人权、汇率和301条款等往往成为其御用工具。最近,美国启动对华新能源政策措施301调查,再次向外界发出了贸易保护主义的错误信号。曾几何时,我们对奥巴马政府出台的发展新能源政策表示赞赏,但由于其国内多种因素的制约,其新能源产业发展并不顺利,近两年的发展速度在下降,而欧洲新能源发展平     

耐火材料使用性能的应用

以耐火材料在济钢中实际应用阐述了耐火材料在设计、检验、使用过程中不仅要考虑其一般性质,更多的应考虑其使用性质.     

对在纵倾式船台进行船舶加长的工艺研究

日本在 80 -90年代生产制造了一批特殊用途的工程船 ,其主机马力大、船型短、宽且型深大、加长改造成普通散装货船经技术、经济论证其投资少、工期短、见效快但保证其性能是关键所在 ,本论文主要研究在满足设计要求的情况下 ,如何进行施工设计、工艺设计以确保改造的成功。     

型煤锅炉节能环保性能评估

以型煤锅炉在丹东市的推广为例,介绍型煤锅炉在丹东市的应用情况。经调查研究,型煤锅炉在实际运行中暴露出型煤发热值低、锅炉出力低、易造成室内环境污染、使用寿命短等问题,影响了其推广使用。最后得出结论:在大力推广型煤锅炉环保方面优点的同时,要改进其缺点从而发挥节能环保产品的作用。     

煤矿机械电气设备自动化调试技术的应用

煤矿业的发展在其社会经济发展中占据极其重要的份额,所以加强对煤矿业机械电气设备自动化调试技术的应用,不仅仅只是实现其煤矿企业在未来社会发展中的可持续性发展的理想目标,同时也有效推动了社会市场经济的高速发展和进步。介绍了在煤矿总产量不断增加的情况下,如何对煤炭生产企业的生产技术、方式和工艺上不断进行技术革新,只有这样才能确保其能安全、正常运行,对煤矿业的发展具有非常重要意义。     

HIT太阳电池中ITO薄膜的结构和光电性能

采用射频磁控溅射技术在不同射频功率下沉积了ITO薄膜,并将其应用于HIT太阳电池。分析了薄膜的结构、光电特性。结果表明,在120W时制备的薄膜很好地兼顾了电阻率和光透过率,其电阻率为3.48×10-4Ω.cm、在350~800 nm波段的平均光透过率为87.1%,将其应用于HIT太阳电池上,电池的转换效率可达13.38%。     

尾矿坝中土工织物滤层反滤试验研究

土工织物作为滤层在尾矿坝排渗设施中已得到广泛应用,但由于工作条件复杂,土工织物经常发生淤堵,导致其排渗能力不足,严重影响尾矿坝的安全。为进一步认识尾矿坝中土工织物滤层的反滤特性,通过改进的梯度比试验装置,对无纺土工织物和不同孔径的有纺土工织物开展了一系列梯度比试验,对比分析了其保土性、防淤堵性和透水性。结果表明,在满足保土性的前提下,有纺土工织物孔径越大,系统的梯度比越小。在长期试验中,有纺土工织物相比于无纺土工织物更易发生淤堵。因此在尾矿工程中有纺土工织物可作为一种短期的排渗滤层,不建议作为长期排渗滤层使用。     

Novel green composites using zein as matrix and jute fibers as reinforcement

We demonstrate that zein-jute fiber composites developed using water plasticized zein as matrix can have substantially higher flexural and tensile properties than composites obtained using polypropylene as matrix. Zein is a plant protein that has been used to develop various types of thermoplastic products. Zein can be extracted from corn distillers dried grains (DDG) with potentially much lower cost than biopolymers in current use. However, thermoplastics developed from zein are brittle and it is necessary to use plasticizers or chemically modify zein to obtain useful zein-based products. Hydrophilic plasticizers such as glycerol that are retained in the composite after fabrication absorb moisture and considerably decrease the properties of the composites. Similarly, chemical modifications make the matrix materials expensive and/or decrease their biodegradability. In this research, we have used water to plasticize zein composites reinforced with jute fibers. Unlike plasticizers such as glycerol, water used as a plasticizer in this research evaporates during composite formation and does not affect the properties of the composites. Zein-jute composites have about 100% higher flexural strength, 82% higher tensile strength than similar PP-jute composites. The zein-jute composites have better flexural and tensile properties than PP-jute composites even at 21 °C and 90% relative humidity. Water serves as an effective plasticizer to utilize zein as a matrix for composites.     

土工织物淤堵试验研究

针对土工管袋在填海造陆时存在的淤堵问题,以江苏省如东县洋口港滩涂淤泥与无纺布、高强度编织布、普通编织布组成的反滤系统为例,采用梯度比试验,在6、8、11三种平均水力梯度下做了9组梯度比试验,测量了土与织物系统的渗透系数、阶段渗土量、梯度比。结果表明,三种土工织物在水力梯度为8、11时,梯度比CR≤3,渗透系数较大,具有良好的反滤性能,未发生淤堵;在水力梯度为6时,土与无纺布、高强度编织布组成的反滤系统CR3,渗透系数很小,发生了淤堵,这可为类似工程提供了参考。     

多层土工织物加固填土路基的特征分析

针对传统的极限平衡分析法不能较好地反映土工织物与土间的变形协调关系,采用非线性有限元法探讨了多层土工织物加固填土路基的变形与破坏特征.结果表明,在假定土工织物与土之间无相对位移条件下,土工织物的铺设层数对路基破坏面的位置影响不明显,路基的潜在破坏面近似为一通过坡趾处的圆弧面;离路基顶面越近,土工织物上的轴力越小;土工织物位于路基中部作用较大,而位于路基坡脚的轴力大为减小;铺设土工织物后,路基的稳定性提高较大,铺设层数越多,路基的安全系数增幅越大;铺设于路基体内的土工织物对减小地基体内的水平位移作用有限,实际工程中需采用其他措施约束地基体内水平位移的处理.     

Synergy effects of hybrid carbon system on properties of composite bipolar plates for fuel cells

A hybrid carbon system of graphite powder (GP) and continuous carbon fibre fabric (CFF) is used for an epoxy composite to improve the electrical conductivity, mechanical properties and mouldability of a composite bipolar plate. These improvements are achieved simultaneously by inserting several layers of CFF into the GP/epoxy composite to enhance the mechanical properties and in-plane conductivity. The electrical properties, flexural strength and mouldability of the composite plates are measured as a function of conducting filler content and number of CFF layers. The composites show improved electrical conductivity, flexural properties and mouldability. Composites with 70-75 vol.% carbon fillers have the highest electrical conductivity with reasonable flexural properties. These results suggest that the poor mouldability and low through-plane electrical conductivity of the continuous fibre composite bipolar plate, as well as the weak flexural properties of GP composites, can be overcome by incorporating a GP/CFF hybrid system.     

基于复合材料理论的冻土强度模型

为建立冻土强度模型,在假定冻土强度由原土强度和冰体强度两部分组成的基础上,基于复合材料理论,利用叠加原理建立了冻土扩展的Mohr-Coulomb强度模型,并分别对理想化模型冻土和均匀化材料模型土进行了有限元计算。结果表明,冻土内的土颗粒体与冰体的变形特征(压缩、膨胀)存在明显差异;纵向冰体中的Von Mises应力明显大于横向冰体中的相应应力。因此,冻土试样的破坏首先是从竖向裂纹开始的。     

Hydrogen rich gas production by thermocatalytic decomposition of kenaf biomass

Kenaf (Hibiscus cannabinus L.), a well known energy crop and an annual herbaceous plant grows very fast with low lodging susceptibility was used as representative lignocellulosic biomass in the present work. Thermocatalytic conversions were performed by aqueous phase reforming (APR) of kenaf hydrolysates and direct gasification of solid biomass of kenaf using 5% Pt on activated carbon as catalyst. Hydrolysates used in APR experiments were prepared by solubilization of kenaf biomass in subcritical water under CO₂ gas pressure.     

Correlation between electrochemical properties of the CNTs/AB5 composite hydrogen storage alloys and their catalytic properties for KBH4

Searching for non-precious metal anode catalysts with high catalytic activity and capable of inhibiting hydrolysis side reactions is very important for direct borohydride fuel cell (DBFC). In this work, the as-cast AB₅ alloy powders are firstly mixed with CNTs in a ratio of 1:9. Then the mixture of AB₅ alloy and CNTs is ball milled in different milling time. Finally, the CNTs/AB₅ composite alloys are obtained. Not only the catalytic properties of the CNTs/AB₅ composite alloys used as anode catalysts in DBFC, but also the electrochemical properties of the alloys have been investigated in detail. The research results indicate that, as the ball milling time is extended, the electrochemical properties and catalytic properties on ΒΗ₄⁻ of the CNTs/AB₅ composite alloys become better first and then worsen. The CNTs/AB₅ alloy milled 2 h exhibits the best electrochemical properties and catalytic properties. Furthermore, we predict that the electrochemical properties of the composite alloy are positively correlated with the catalytic properties as anode catalyst for DBFC.     

根系退化对根土复合土体的影响

为探索根系自然腐烂对其自身抗拉能力及根土复合体力学性能的影响,测定了种植狗牙根的红粘土的基本物理力学性能指标,并制备狗牙根自然退化0、3、6个月情况下的重塑含根土、原状含根土试样进行三轴试验。结果表明,狗牙根根系进入退化状态后,抵抗拉力的能力随时间明显降低,退化6个月时根系已腐烂,完全不具有力学性能;退化3个月时,重塑含根土和原状含根土的抗剪强度均发生不同程度的衰减;退化6个月的根系使根土复合体降低52%左右的强度,对土体造成极大损伤。     

Gasification efficiencies of cellulose,hemicellulose and lignin fractions of biomass in aqueous media by using Pt on activated carbon catalyst

The diversity in the chemical composition of lignocellulosic feedstocks can affect the conversion technologies employed for biofuel production. Aqueous-phase reforming (APR) activities of cellulose, hemicellulose and lignin components of lignocellulosic biomass materials were evaluated for production of hydrogen content gas mixture using platinum catalyst on activated carbon support. Wheat straw, an abundant by-product from wheat production and kenaf (Hibiscus cannabinus L.), an annual herbaceous plant growing very fast with low lodging susceptibility were used as lignocellulosics in the present study. The hydrolysates of cellulose fractions of biomass materials showed the best performance for gasification. The results indicated that hemicellulose isolated from kenaf was more sensitive to degradation and therefore, produced more gaseous products than that of wheat straw. The hemicellulose isolated from kenaf biomass left the lowest amount of ungasified solid residue in APR among other cellulose and hemicellulose materials studied. Lignin fractions of both biomass materials were not reactive in APR to produce hydrogen rich gas mixture.Gasification efficiencies of kenaf and wheat straw's hemicelluloses were also compared with xylans from beechwood and oat spelts which were commercially available as hemicellulosic fractions.Oat spelts xylan showed better reforming activity over the beechwood xylan.