Research on Composite Errors of Long Gage Blocks

The factor having effect on compostie errors of long gage blocks and their control are discussed, and a ba-sis is therefore provided for driprovement of composite accuracy. Calculations and experiments were conduted for de-formation error resulting for clamp foree and the effect of additional bending moment on parallelism of the measure-ment surfaces. With gage blocks of different length in good conact, clamp force and suppotrs properly chosen, the composite error can be controlled within 0.1μp by reducing or eliminating the effect of additional bending moment on parallelism of measurement surfaces.

Corundum Based Composite Block Containing Plastic Phase

1 Scope This standard specifies the definition, classification, technical requirements, test methods, inspection rules, packing, marking, transportation and quality certificate of corundum block containing plastic phase.

Portland Cement-Residues-Polymers Composites and Its Application to the Hollow Blocks Manufacturing

Agricultural wastes and sawdust combined with cement matrix in the manufacture of building elements has been practiced with success in developed countries. In this study, sawdust from wood species (Pinus caribaea and Eucalyptus grandis) and an agricultural waste—rice husk (Oriza sativa) were combined with Portland cement type V (high initial strength), modified by polymer styrene-butadiene (SBR) addition. Hollow blocks produced with Eucalyptus grandis and rice husk residues showed better compressive strength;however, those produced with residues derived from Pinus caribaea presented non-satisfactory results, due to the particle size that was used.

C-V Characterization of α-Fe_2O_3/Block-Copolymer Composite Particulate Films

α-Fe_2O_3 nanocrystal was encapsulated by a block-copolymer, hydroxylated poly (styrene-b- butadiene-styrene) (HO-SBS) to fabricate composite microspheres with α-Fe_2O_3 cores and HOSBS shell. Its film fabricated on n-Si wafer acts as the insulator layer in the metal-insulator- semiconductor(MIS) structure. The capacitance-voltage (C-V) properties were measured to characterize the composite particulate films.

Coordinate unification method of high-precision composite measurement in two dimensions

Multi-sensor coordinate unification in dimensional metrology is used in order to get holistic, more accurate and reliable information about a workpiece based on several or multiple measurement values from one or more sensors. Because of the problem that standard ball is deficient as a standard artifact in the coordinate unification of high-precision composite measurement in two dimensions （2D） , a new method is proposed in this paper which uses angle gauge blocks as standard artifacts to achieve coordinate unification between the image sensor and the tactile probe. By comparing the standard ball with the angle gauge block as a standard artifact, theoretical analysis and experimental results are given to prove that it is more precise and more convenient to use angle gauge blocks as standard artifacts to achieve coordinate unification of high-precision composite measurement in two dimensions.

Influence of thickness and projectile shape on penetration resistance of the compliant composite

The present study deals with development of conceptual proof for jute rubber based flexible composite block to completely arrest the projectile impacting the target at high velocity impact of 400 m/s through numerical simulation approach using finite element(FE)method.The proposed flexible composite blocks of repeating jute/rubber/jute(JRJ)units are modelled with varying thickness from 30 mm to 120 mm in increments of 30 mm and impacted by flat(F),ogival(O)and hemispherical(HS)shaped projectiles.All the considered projectiles are impacted with proposed flexible composite blocks of different thicknesses and the penetration behaviour of the projectile in each case is studied.The penetration depth of the projectile in case of partially penetrated cases are considered and the effect of thickness and projectile shape on percentage of penetration depth is statistically analyzed using Taguchi’s design of experiments(DOE).Results reveal that the though proposed flexible composite block with thickness of 90 mm is just sufficient to arrest the complete penetration of the projectile,considering the safety issues,it is recommended to use the flexible composite with thickness of 120 mm.The nature of damage caused by the projectile in the flexible composite is also studied.Statistical studies show that thickness of the block plays a prominent role in determining the damage resistance of the flexible composite.

Preparation technique of SiCp reinforced Al matrix composite

A new preparation technique-"block dispersal and cast" method is introduced, and three kinds of powder mixing methods, vertical, horizontal and inclining styles, are compared. The results demonstrate that the inclining style is the best way to mix powders. The Al and nano SiC powders are pressed into blocks, dipped into molten Al, stirred into mold so that SiC/Al matrix composites can be obtained at last. The microstructure of SiC particle reinforced Al matrix composite prepared by "block dispersal and cast" method have been studied using scanning electron microscopy (SEM). Phase analysis has also been conducted by means of X-ray diffraction (XRD). The results show that nano SiC particles can be dispersed uniformly in Al matrix. Thus, it is feasible to prepare SiC particle reinforced Al matrix composites by this method.

STUDIES ON POLY(ETHYLENE TEREPHTHA LATE)-POLY(TETRAMETHYLENE ETHER) MULTIBLOCK COPOLYMER.Ⅰ.COMPOSITIONAL HOMOGENEITY

The compositional homogeneity of a poly (ethylene terephthalate)-poly (tetramethylene ether) multiblock copolymer sample with low content of hard segment was examined by GPC, TLC, and solubility method. The copolymer sample was found to have a uniform composition as a function of elution volume over the major portion of sample from GPC method. However within one elution fraction, the copolymer chains, although having the same hydrodynamic volume, may have some difference in composition. Two fractions with different composition were obtained by precipitation in ethanol. Some low molar mass copolymers were also separated by a TLC technique from the copolymer sample.

Sulfur/carbon composites prepared with ordered porous carbon for Li-S battery cathode

Ordered porous cabon with a 2-D hexagonal structure,high specific surface area and large pore volume was synthesized through a twostep heating method using tri-block copolymer as template and phenolic resin as carbon precursor.The results indicated the electrochemical performance of the sulfur/carbon composites prepared with the ordered porous carbon was significantly affected by the pore structure of the carbon.Both the specific capacity and cycling stability of the sulfur/carbon composites were improved using the bimodal micro/meso-porous carbon frameworks with high surface area.Its initial discharge capacity can be as high as 1200 mAh·g-1 at a current density of 167.5 mA·g-1The improved capacity retention was obtained during the cell cycling as well.

The late Early-Paleozoic granitic magmatism in Northwestern Fujian, China: constraints on intraplate orogeny in the South China block

The Early Paleozoic tectono-thermal event was a significant orogenic activity during the Phanerozoic era,which had a profound impact on the early crust of the South China Block(SCB) and established the foundation for later tectonic activity.The Wuyi-Yunkai orogenic belt in Southeastern China was extensively exposed to Early Paleozoic magmatism,the genetic mechanism of which remains controversial.To shed light on this issue,detailed petrological,geochemical,and zircon U-Pb-Hf isotopic studies were carried out on two granitoids,namely the Yuntongshan pluton and the Gaoqiao pluton,identified in the central Wuyishan.Zircon U-Pb chronology of the Yuntongshan and Gaoqiao bodies yielded ages of437±4 Ma(MSWD=2.2) and 404±2 Ma(MSWD=12),respectively,indicating that they were emplaced during the Early Silurian and Early Devonian periods.These granitoids are primarily composed of biotite-granite and biotite-monzonitic-granites,with high concentrations of S_(i)O_(2)(73.59-75.91 wt%),K_(2)O+Na_(2)O(8.31-8.73wt%),and low contents of MgO,CaO,Cr,Ni.They are classified as high-K calc-alkaline and weakly metaluminous-strongly peraluminous S-type granites.These granitoids are enriched in light rare earth elements(LREEs) and large ion lithophile elements(LILEs) and depleted in heavy rare earth elements(HREEs) and high field strength elements(HFSEs) with arc affinity.The εHf(t) values of-3.3 to-15.4 with two-stage Hf model ages ranging from 2829 to 1644 Ma,combined with the presence of Neoproterozoic inherited zircons,suggest that the primary magma of these granitoids was derived from the partial melting of Neoproterozoic crust with a Paleoproterozoic crustal model age.These findings,combined with the spatio-temporal distribution of regional magmatism,reveal that the late Early-Paleozoic granitoids formed in the intraplate orogenic background originating from the subduction of the proto-Tethys Ocean and proto-Pacific Ocean around the margin of the east Gondwana supercontinent.

Attribution of the Langshan Tectonic Belt: Evidence from zircon U-Pb ages and Hf isotope compositions

This study describes a previously unidentified Neoproterozoic mafic dyke emplaced in the northern flank of the Langshan Tectonic Belt. This dyke intruded into the micaquartz schist of the Zhaertaishan Group, and yielded an age of 908 ± 8 Ma. The youngest U-Pb ages of micaquartz schist from the Zhaertaishan Group in the Langshan area were 1118 ± 33 Ma,1187 ± 3 Ma and 1189 ± 39 Ma,suggesting that the depositional age of the protolith of the schist was between 908 ± 8 Ma and 1118 ± 33 Ma. In addition, 436 U-Pb age data and 155 Lu-Hf isotopic data from six samples in the Langshan Tectonic Belt and one Permian greywacke from the Wuhai area show distinct differences between the northern and southern flanks of the Main Langshan area. The U-Pb ages of the northern flank are primarily Meso-Neoproterozoic; similar ages have not been identified in the southern flank to date.Moreover, two-stage Hf model ages of the northern flank feature three age peaks at ～900 Ma,～1700 Ma and ～2600 Ma; this differs from Hf model ages of the southern flank, which feature one strong age peak at ～2700 Ma. These results suggest that the northern and southern flanks of the Main Langshan area have different geochronologic characteristics and should be divided further. Based on the U-Pb ages and Hf model ages, the northern and southern flanks of the Main Langshan area are named the North and South Langshan Tectonic Belts. Comparison of the U-Pb age and two-stage Hf model age distributions from the North Langshan Tectonic Belt, South Langshan Tectonic Belt, Alxa Block and the North China Craton(NCC) reveal that the North Langshan Tectonic Belt is similar to the Alxa Block and that the South Langshan Tectonic Belt is similar to the NCC. In addition, the zircon U-Pb age of 860 ±7 Ma commonly observed in the Alxa Block was detected in the Permian greywacke from the Wuhai area of the NCC, which suggests that the amalgamation of the North and South Langshan Tectonic belts(i.e.,the amalgamation of the Alxa Block and the NCC), occurred between Devonian and late Permian.

POSSIBLE RELATIONSHIP BETWEEN ENSO AND BLOCKING IN KEY REGIONS OF EURASIA

Using reanalysis data provided by the U.S. National Centers for Environmental Prediction/National Center for Atmospheric Research, the potential relationship between the E1 Nifio-Southern Oscillation （ENSO） cycle and blocking highs in three key regions of Eurasia （Ural, Baikal, and Okhotsk） from 1950 to 2008 is analyzed. Composite analysis of 500 hPa geopotential height field during different stages of ENSO reveals that in the winters of E1 Nifio （EN） years, there is significant negative anomaly of geopotential height in the three key regions. In the winters of La Nifia （LN） years, on the other hand, significant positive anomaly of geopotential height is observed in Eastern Ural, Baikal, and Okhotsk. In summer, Okhotsk exhibits positive anomaly, which is significant at a confidence level of 90% by Student＇s t-test during the developing stage of an LN year. In the developing stage of an EN year, geopotential height field at 500 hPa manifests positive （negative） anomaly in Baikal （Ural and Okhotsk）, while the geopotential height field at 500 hPa exhibits positive （negative） anomaly in Ural and Okhotsk （Baikal） during the decaying stage of both EN and LN years. However, these abnormities are insignificant in a developing EN year, decaying EN year, and the summer of a decaying LN year. By analyzing 500 hPa geopotential height field during different phases of the ENSO cycle, it is observed that results of the case study are consistent with those of composite analysis. Annual average blocking is likewise examined during the different stages of ENSO from 1950 to 2008. Combined with composite analysis and case study, results indicate that blockings in the three key regions are suppressed （enhanced） during the winters of EN （LN） years. In summer, the influence of ENSO on the blockings in the three key regions is not as significant as that in winter. Evidently, developing LN may enhance blockings in Okhotsk. Influence factors on blockings are various and complex. This paper indicates that the influence of ENSO on blockings cannot be neglected, and that it is crucial to related operational forecasting as a potential signal.

Application and practice of ceramic fiber block technology in industrial furnaces

Ceramic fiber,a kind of furnace lining material, is widely utilized in industrial furnaces. Fiber blocks can be made into various shapes. They have advantages of low thermal conductivity, low density and light weight for the development of industrial furnaces, This paper, taking a continuous annealing furnace as an example, describes the application of ceramic fiber blocks in the furnace and the installation methods. The temperatures of the furnace wall with different linings are analyzed. In the furnace design or the renovation of the existing furnaces, lining with ceramic fiber blocks is the preferred solution.

钢管混凝土双块式轨枕道床复合受力性能试验

新型钢管混凝土(CFT)双块式轨枕采用钢管混凝土取代了桁架钢筋的连接构件作用,具有结构简单、安全耐久性好等优点。为研究钢管混凝土双块式轨枕与现浇混凝土道床所形成的轨道结构的复合受力性能,采用某实际工程的材料和工艺制作了一段足尺CFT轨枕减振道床和现浇整体道床,经疲劳试验验证后,用绳锯将其沿横向切割成单承轨台和双承轨台的CFT轨枕道床试件,分别开展试件的轨下截面加载试验和中间截面加载试验,分析道床试件中轨枕、现浇道床、底座板混凝土和钢筋的应力、变形及裂缝的开展演化规律。试验结果表明:CFT轨枕道床受力破坏过程均表现出整体工作、带裂缝工作和破坏的典型三阶段特征;中间截面加载试件破坏时受拉钢筋被拉断而受压区混凝土未被压碎,类似于低筋破坏,轨下截面加载试件因竖向裂缝和弯剪区段斜裂缝之间的混凝土被压碎剥落而失效,受拉纵筋未屈服,类似于斜压破坏;CFT轨枕整体道床试件抗裂能力、承载能力更高,整体道床试件开裂荷载约为减振道床试件相应值的4.7倍,其极限荷载约为减振道床的2.3倍,道床与底座板之间采用拉结钢筋连接后能大幅提升轨道结构刚度和承载能力。CFT轨枕与现浇道床界面黏结及整体工作性能良好,研究成果可供钢管混凝土双块式无砟轨道理论研究和工程应用参考。

适合延长油田低渗透储层分层注水井的有机酸解堵体系

为了解决延长油田低渗透储层分层注水井注入压力升高以及注水量下降的问题,以复合有机酸FH-S为主体酸液,结合黏土稳定剂、缓蚀剂和助排剂等主要处理剂,研制了一套适合延长油田低渗透储层分层注水井的有机酸解堵体系,室内对其基本性能和岩心驱替解堵性能进行了评价。结果表明:有机酸解堵体系具有良好的溶蚀性能、缓蚀性能和较强的铁离子稳定能力,降低表面张力和界面张力的效果也较好,体系与地层水的配伍性较好,不会出现浑浊和沉淀;另外,在天然岩心被注入水污染后挤入2 PV有机酸解堵体系,能够有效解除堵塞污染,岩心驱替压力明显降低,岩心渗透率恢复值可以达到100%以上,解堵效果较好。现场应用结果表明:目标注水区块5口注水井采取有机酸解堵体系施工措施后,注入压力显著降低,日注水量明显增大,并且措施的有效期较长,取得了良好的现场施工效果。

沼液滴灌条件下不同类型灌水器的堵塞特征

为了探求不同类型灌水器在沼液滴灌中的抗堵塞性能,研发适用于沼液滴灌的灌水器,明确沼液滴灌条件下灌水器的堵塞类型。选用内镶贴片式灌水器(1.38、2、3 L/h)、内镶圆柱式灌水器(2、3 L/h)、压力补偿式灌水器(2、4、6 L/h)三类灌水器,在灌水压力0.08 MPa、水沼液配比4∶1(体积比)条件下进行周期性间歇灌水试验,比较不同灌水器的堵塞情况,并使用扫描电镜分析堵塞物的粒径大小及各粒径占比情况,同时结合堵塞物的傅里叶红外光谱图分析堵塞物的组成成分。结果表明,8种灌水器(E1~E8)达到堵塞标准所需的时间分别为108、126、141、111、132、84、102和117 h;灌水器堵塞物在出水口、进水口以及过水流道内均有分布,进水口处为黄色泥沙沉积,出水口及过水流道拐角处为黑色絮状物;堵塞物成分为沙粒、碳酸盐、硫酸盐、磷酸盐等无机化合物以及烃类、蛋白质、脂类等有机物;堵塞物中88.42%的颗粒物粒径集中在0.2~1.4μm的粒径范围内,其余11.58%为大絮状物。综上所述,同类型灌水器中,额定流量越大的灌水器达到堵塞标准所需的时间越长,抗堵塞性能越好;同额定流量的灌水器,内镶贴片式灌水器的抗堵塞性能最佳;额定流量3 L/h的内镶贴片式灌水器的抗堵塞性能最佳;灌水器发生的堵塞类型为物理-化学-生物三者协同作用导致的复合型堵塞。

马鞍山长江公铁大桥主航道桥中塔下横梁施工关键技术

马鞍山长江公铁大桥主航道桥Z4号中塔采用空间四肢A形钢-混组合塔,横向两塔肢间设下横梁,下横梁间设3道系梁,纵向两塔肢间不设置横梁。下横梁采用支架法分层浇筑施工。下横梁施工支架采用落地式钢管支架配套模板体系,受力性能满足要求;通过有限元计算比选下横梁混凝土分层浇筑方案并进行优化,采取(5.5+2.5)m分层方案,上、下层混凝土分别分为2块、3块分层分块浇筑;通过低温升、易泵送、高抗裂的C60混凝土研制、下横梁与塔柱倒弧结合面抗裂措施优化、分块间接缝构造形式及施工工艺优化、下横梁与系梁混凝土浇筑施工组织优化、混凝土温度智能化监控、预应力束张拉时机控制等混凝土防裂措施,有效解决了下横梁大体积混凝土易开裂的难题。

木质素基紫外阻隔膜材料的研究进展

本文基于与纤维素、可降解塑料和其他聚合物材料复合的3种木质素复合材料体系,总结了木质素基紫外阻隔膜材料的研究进展。阐述了木质素分子结构与紫外吸收性能的相关性,以及其对复合材料光稳定性、力学强度和阻隔性能等方面的影响。对木质素在不同复合膜材料体系中的提升机制和膜材料的功能应用进行了讨论。此外,基于木质素的紫外吸收等功能特性,对其在多功能复合膜材料的开发和潜在应用进行了展望,为木质素高值转化和利用提供一定参考。

临兴气田井筒堵塞机理及现场解堵工艺研究

临兴区块自投产以来,井筒堵塞问题日益严重,导致气井生产测试、措施作业等无法正常开展。文章结合区块堵塞物的粒径分析、无机成分XRD、红外等分析结果,明确了堵塞物成分主要包括石英、石盐、难溶盐垢(以硅铝酸盐垢为主)及少量的铁垢和固体砂砾等,主要堵塞类型为砂堵、腐蚀结垢及结盐堵塞等。通过解堵实验,优选出HYJD-10和CAWF两种解堵剂体系,静态溶蚀实验最高溶解率分别可达25.3%及18.3%,驱替实验最优渗透率的提高率分别可达105.9%及91.3%。现场结合注解堵剂、气举及泡沫流体等方式进行解堵作业,单井平均增产不小于9 000 m3/d,最高增产25 000 m3/d。本研究为致密气井井筒解堵试验提供了参考。

复合保温板与加气混凝土砌块墙体一体化施工力学性能研究

针对复合保温板与砌块填充墙连接的安全性,采用HC-MD60高精度铆钉拉拔仪,进行锚栓抗拉承载力和复合保温板拉伸黏结强度现场原位检测试验。测试结果表明:锚栓抗拉承载力平均值为2.345 kN,复合保温板表面抗裂加强层与保温芯材之间的黏结强度平均值为0.17 MPa,复合保温板内侧黏接层与砌块墙体黏结强度为0.1 MPa,黏锚结合的力学性能满足DB/T 29-281—2020《天津市外模板现浇混凝土复合保温系统应用技术规范》要求。