Performance and Application of Double-layered Microcapsule Corrosion Inhibitors

Double-layered microcapsule corrosion inhibitors were developed by sodium monofluorophosphate as the core material,polymethyl methacrylate as the inner wall material,and polyvinyl alcohol as the outer wall material combining the solvent evaporation method and spray drying method.The protection by the outer capsule wall was used to prolong the service life of the corrosion inhibitor.The dispersion,encapsulation,thermal stability of microcapsules,and the degradation rate of capsule wall in concrete pore solution were analyzed by ultra-deep field microscopy,scanning electron microscopy,thermal analyzer,and sodium ion release rate analysis.The microcapsules were incorporated into mortar samples containing steel reinforcement,and the effects of double-layered microcapsule corrosion inhibitors on the performance of the cement matrix and the actual corrosion-inhibiting effect were analyzed.The experimental results show that the double-layered microcapsules have a moderate particle size and uniform distribution,and the capsules were completely wrapped.The microcapsules as a whole have good thermal stability below 230 ℃.The monolayer membrane structure microcapsules completely broke within 1 day in the simulated concrete pore solution,and the double-layer membrane structure prolonged the service life of the microcapsules to 80 days in the simulated concrete pore solution before the core material was completely released.The mortar samples containing steel reinforcement incorporated with the double-layered microcapsule corrosion inhibitors still maintained a higher corrosion potential than the monolayer microcapsule corrosion inhibitors control group at 60 days.The incorporation of double-layered microcapsules into the cement matrix has no significant adverse effect on the setting time and early strength.

THE DOUBLE-LAYER STRUCTURE OF THE HADLEY CIRCULATION AND ITS INTERDECADAL EVOLUTION CHARACTERISTICS

Based on the three-pattern decomposition of global atmospheric circulation(TPDGAC), this study investigates the double-layer structure of the Hadley circulation(HC) and its interdecadal evolution characteristics by using monthly horizontal wind field from NCEP/NCAR reanalysis data from 1948—2011. The following major conclusions are drawn: First, the double-layer structure of the HC is an objective fact, and it constantly exists in April,May, June, October and November in the Southern Hemisphere. Second, the double-layer structure is more obvious in the Southern than in the Northern Hemisphere. Since the double-layer structure is sloped in the vertical direction, it should be taken into consideration when analyzing the variations of the strength and location of the center of the HC.Third, the strength of the double-layer structure of the HC in the Southern Hemisphere consistently exhibits decadal variations with a strong, weak and strong pattern in all five months(April, May, June, October, and November), with cycles of 20-30 a and 40-60 a. Fourth, the center of the HC(mean position of the double-layer structure) in the Southern Hemisphere consistently and remarkably shifts southward in all the five months. The net poleward shifts over the 64 years are 5.18°, 2.11°, 2.50°, 1.79° and 5.76° for the five respective months, with a mean shift of 3.47°.

Numerical Analysis of the Structure of High-Strength Double-Layer Steel Plate Concrete Shaft by Drilling Method of Water-Bearing Weak Rock Formation

In order to ensure the safety of coal mine shaft construction, a double-layer steel plate concrete composite shaft wall structure was proposed. However, fewer studies were conducted on this structure, which made engineers too confused to fully recognize its feasibility of this structure. Hence, based on the previous experimental research on the Taohutu mine construction project in Ordos in Inner Mongolia, this research paper aims to provide a widely deep numerical analysis by the usage of the finite element software, in fact, to establish the corresponding numerical analysis model and make a comparison with the experimental data to get the rationality of the verified model. The influence of the composite characteristics of the steel plate and concrete on the ultimate bearing capacity and stress field of the shaft wall structure is studied here through the method of multi-factor analysis. Also, the optimal design scheme of the double-layer steel plate and concrete composite shaft wall structure is proposed in this research paper.

Preparation and Microwave Absorbing Properties of Double-layer Fine Iron Tailings Cementitious Materials

To develop the microwave absorbing(MA)properties of cementitious material mixed with mine solid waste,the iron tailings cementitious microwave absorbing materials were prepared.The iron tailings was treated into different particle sizes by planetary ball mill,and the physicochemical properties of iron tailings were tested by laser particle size analyzer and scanning electron microscope(SEM).The electromagnetic parameters of iron tailings cementitious materials were characterized by a vector network analyzer and simulated MA properties,and the MA properties of iron tailings-cement composite system with steel fiber as absorber was studied.Based on the design of the single-layer structure,optimum mix ratio and thickness configuration method of double-layer structure were further studied,meanwhile,the mechanical properties and engineering application were analyzed and discussed.The results show that the particle size of iron tailings can afiect its electromagnetic behavior in cementitious materials,and the smaller particles lead the increase of demagnetisation efiect induced by domain wall motion and achieve better microwave absorbing properties in cementitious materials.When the thickness of matching layer and absorbing layer is 5 mm,the optimized microwave absorbing properties of C1/C3 double-layer cementitious material can obtain optimal RL value of-27.61 dB and efiective absorbing bandwidth of 0.97 GHz,which attributes to the synergistic efiect of impedance matching and attenuation characteristics.The double-layer microwave absorbing materials obtain excellent absorbing properties and show great design flexibility and diversity,which can be used as a suitable candidate for the preparation of favorable microwave absorbing cementitious materials.

Double-layer microwave absorber of nanocrystalline strontium ferrite and iron microfibers

Microwave absorption properties of the nanocrystalline strontium ferrite （SrFe12O19） and iron （α-Fe） microfibers for single-layer and double-layer structures are investigated in a frequency range of 2 GHz 18 GHz. For the singlelayer absorbers, the nanocrystalline SrFe12O19 microfibers show some microwave absorptions at 6 GHz 18 GHz, with a minimum reflection loss （RL） value of -11.9 dB at 14.1 GHz for a specimen thickness of 3.0 mm, while for the nanocrystalline α-Fe microfibers, their absorptions largely take place at 15 GHz-18 GHz with the RL value exceeding -10 dB, with a minimum .RL value of about -24 dB at 17.5 GHz for a specimen thickness of 0.7 mm. For the doublelayer absorber with an absorbing layer of α-Fe microfibers with a thickness of 0.7 mm and matching layer of SrFe12O19 microfibers with a thickness of 1.3 ram, the minimum RL value is about -63 dB at 16.4 GHz and the absorption band width is about 6.7 GHz ranging from 11.3 GHz to 18 GHz with the RL value exceeding -10 dB which covers the whole Ku-band （12.4 GHz 18 GHz） and 27% of X-band （8.2 GHz 12.4 GHz）.

Double-layer indium doped zinc oxide for silicon thin-film solar cell prepared by ultrasonic spray pyrolysis

Indium doped zinc oxide （ZnO：In） thin films were prepared by ultrasonic spray pyrolysis on corning eagle 2000 glass substrate. 1 and 2 at.% indium doped single-layer ZnO：In thin films with different amounts of acetic acid added in the initial solution were fabricated. The 1 at.% indium doped single-layers have triangle grains. The 2 at.% indium doped single-layer with 0.18 acetic acid adding has the resistivity of 6.82 × 10^-3 Ω. cm and particle grains. The doublelayers structure is designed to fabricate the ZnO：In thin film with low resistivity （2.58 × 10^-3 Ω. cm） and good surface morphology. It is found that the surface morphology of the double-layer ZnO：In film strongly depends on the substratelayer, and the second-layer plays a large part in the resistivity of the doublewlayer ZnO：In thin film. Both total and direct transmittances of the double-layer ZnO：In film are above 80% in the visible light region. Single junction a-Si：H solar cell based on the double-layer ZnO：In as front electrode is also investigated.

深部矿山高承压应急防水闸门设计计算与数值模拟研究——以滇东北毛坪铅锌矿为例

应急防水闸门及其配套工程在水害发生时,能够在短时间内有效控制水害的影响范围和程度,保障机械设备和人员安全。随着矿山开采深度的逐年增加,应急防水闸门及闸门硐室所需要承受的水压也在不断增加,地质条件更加复杂,施工环境也更加恶劣。本文以滇东北大水矿山毛坪铅锌矿为例,在系统评价其310 m中段局部注浆改造前后突水风险的基础上,分析了深部高承压应急防水闸门设计和建造过程中的多项关键技术问题,主要包括防水闸门设计承压值计算、硐室选址、结构类型、关键结构参数、开挖围岩扰动、围岩与结构的水压响应、闸门选型与远程控制系统等。设计计算结果表明,毛坪铅锌矿310 m中段应采用倒截锥形硐室结构,对开型防水闸门,设计承压6.4 MPa。数值模拟结果表明,防水闸门硐室开挖及浇筑后,竖直和水平方向的压应力和拉应力均增大,围岩塑性破坏的范围约为0.38 m,第1个倒截锥形塞的迎水侧承担了超过80%的总水压。最后,探讨了深部高承压应急防水闸门系统的发展趋势,包括防水闸门及硐室结构长期服役的稳定性监测与评价、深部复杂地质条件下的设计与建造技术、配套智能化的水害信息辨识与预警平台等。研究结果可以为深部矿山设计和建造应急防水闸门系统提供参考和借鉴。

Influence of secondary lining thickness on mechanical behaviours of double-layer lining in large-diameter shield tunnels

In large-diameter shield tunnels,applying the double-layer lining structure can improve the load-bearing properties and maintain the stability of segmental lining.The secondary lining thickness is a key parameter in the design of a double lining structure,which is worth being explored.Based on an actual large-diameter shield tunnel,loading model tests are carried out to investigate the effect of the secondary lining thickness on the mechanical behaviours of the double lining structure.The test results show that within the range of secondary lining thicknesses discussed,the load-bearing limit of the double-layer lining increases with growing secondary lining thickness.As a passive support,the secondary lining acts as an auxiliary load-bearing structure by contacting the segment.And changes in secondary lining thickness have a significant effect on the contact state between the segment and secondary lining,with both the contact pressure level and the contact area between the two varying.For double-layer lining structures in large-diameter shield tunnels,it is proposed that the stiffness of the secondary lining needs to be matched to the stiffness of the segment,as this allows them to have a coordinated deformation and a good joint load-bearing effect.

Ultrahigh-power electrochemical double-layer capacitors based on structurally integrated 3D carbon tube arrays

The rational design of electrodes is the key to achieving ultrahigh-power performance in electrochemical energy storage devices.Recently,we have constructed well-organized and integrated three-dimensional(3D)carbon tube(CT)grids(3D-CTGs)using a 3D porous anodic aluminum oxide template-assisted method as electrodes of electrical double-layer capacitors(EDLCs),showing excellent frequency response performance.The unique design warrants fast ion migration channels,excellent electronic conductivity,and good structural stability.This study achieved one of the highest carbon-based ultrahigh-power EDLCs with the 3D-CTG electrodes,resulting in ultrahigh power of 437 and 1708 W·cm−3 with aqueous and organic electrolytes,respectively.Capacitors constructed with these electrodes would have important application prospects in the ultrahigh-power output.The rational design and fabrication of the 3D-CTGs electrodes have demonstrated their capability to build capacitors with ultrahighpower performance and open up new possibilities for applications requiring high-power output.

某型集装箱船舱壁变形原因分析及工艺优化

某国际航行集装箱船在建造过程中货舱后端壁产生褶皱变形,针对此问题进行强度校核和工艺流程两个方面的原因剖析。通过船级社规范计算和有限元校核的方法,对产生变形的舱壁在下水、强度试验等各个阶段进行结构强度分析,再与同型船施工顺序、建造工艺进行对比,得出舱壁变形是由下水和主机吊装时机不合理导致,最终提出工艺改进优化措施,有效解决了后续船舱壁变形的问题。

斜顶板桩承台接岸结构优化设计

针对斜顶板桩承台接岸结构造价较高的问题,结合洋山港区实际应用情况进行优化设计研究。采用与已建结构相同的计算方法进行使用条件和结构受力特点的对比分析,得出类似结构在软土地基的大型集装箱码头中应用可以显著优化结构。采取分级实施墙后棱体、取消后排支撑桩、利用组合钢板桩优化密排钢管板桩、将承台简化为导梁等优化措施,形成一种新的半直立式接岸结构形式,即斜顶板桩结构。结果表明:斜顶板桩与下级棱体组成的独立稳定结构体系较好地适应了前期软土地基高填土的变形特点和后期上部结构的使用要求。新结构更合理地利用桩基结构承载能力,明显提高了经济性,有利于在软基地区的类似工程中推广。

某河道双体承压舟浮桥结构优化设计分析

以实际项目的双体承压舟浮桥结构设计为背景,对不同横舱壁位置、底封板数量和连接桥跨度下的承压舟结构受力进行了对比分析。建议保留原设计方案的横舱壁设计,底封板数量应由4块增加至8块,可适当增加连接桥跨度以提升汛期泄流和河中漂浮物通过的能力。

隔舱密封装置结构设计及性能研究

介绍了一种新型的隔舱密封装置结构与设计原理。通过建立数值仿真模型,对该装置的密封性能进行仿真分析;搭建台架试验,针对隔舱密封装置的性能进行了试验。结果表明,该新型隔舱密封装置具有可靠性高、密封压力大等优点,其各项性能指标均能满足工作需求。

酒钢本部烧结工序提质增效生产实践

对酒钢本部烧结工序四台烧结机、两座竖炉的提质增效实践过程进行总结,通过配料结构优化调整、烧结系统漏风治理、风箱隔梁技术改造以及多项技术创新应用等措施,烧结机和竖炉的台时产量、成品实物质量均得到提升,达到了烧结工序持续降本增效的目的。

Preparation and properties of T-ZnO_(w) enhanced BCP scaffolds with double-layer structure by digital light processing

Bone scaffolds require both good bioactivity and mechanical properties to keep shape and promote bone repair.In this work,T-ZnO_(w) enhanced biphasic calcium phosphate(BCP)scaffolds with triply periodic minimal surface(TPMS)-based double-layer porous structure were fabricated by digital light processing(DLP)with high precision.Property of suspension was first discussed to obtain better printing quality.After sintering,T-ZnO_(w) reacts with b-tricalcium phosphate(β-TCP)to form Ca_(19)Zn_(2)(PO_(4))14,and inhibits the phase transition toα-TCP.With the content of T-ZnO_(w) increasing from 0 to 2 wt%,the flexural strength increases from 40.9 to 68.5 MPa because the four-needle whiskers can disperse stress,and have the effect of pulling out as well as fracture toughening.However,excessive whiskers will reduce the cure depth,and cause more printing defects,thus reducing the mechanical strength.Besides,T-ZnO_(w) accelerates the deposition of apatite,and the sample with 2 wt%T-ZnO_(w) shows the fastest mineralization rate.The good biocompatibility has been proved by cell proliferation test.Results confirmed that doping T-ZnO_(w) can improve the mechanical strength of BCP scaffolds,and keep good biological property,which provides a new strategy for better bone repair.

Calculation of the Added Mass of a Liquid Tank's Bulkheads

The added mass coefficient and the water level index formulas for the same-phase and anti-phase vibration of rectangular liquid tanks' bulkheads were derived based on dry mode theory. Three fluid-structure interaction numerical methods including Fluid FEM and Fluid BEM were used in this case. The comparison of numerical and theoretical results by the present method shows that ANSYS/Fluid80 is more credible, the NASTRAN/Virtual Mass Method is more suitable for engineering calculations and results of the same-phase vibration by the present method is more accurate.

典型舱室在战斗部内爆下的载荷及毁伤特性试验研究

[目的]探讨有/无防护舱壁结构对典型舱室在战斗部内爆下载荷及毁伤特性的影响,指导舰船重要舱室的防护设计。[方法]设计典型的双舱结构模型,以大舱室模拟爆炸当舱,小舱室模拟重要舱室,开展常规钢制舱壁与多层含液防护舱壁这2种舱室结构在6.12 kg TNT带壳装药内爆作用下的载荷及毁伤对比试验,分析破片及冲击波载荷特性,以及结构破口及变形毁伤特征。[结果]结果显示,柱锥形战斗部前端产生的破片的飞散角基本一致,且前端的破片数量少于环向破片数量;爆炸冲击波有明显的角隅汇聚特点,冲击波能量会随结构的强弱发生流向改变,整体能量更易向结构较薄弱处倾泻;在冲击波和破片的联合毁伤下,常规钢制横舱壁中心会产生大破口,而多层含液防护舱壁则仅迎弹面有较大的塑性变形及少量破片穿孔,背弹面结构完整;多层含液防护舱壁能有效阻止爆炸能量传递至邻舱,但会加剧爆炸当舱的结构毁伤。[结论]“疏堵”(舱壁加强或减弱)防护设计方法在舰船重要舱室防护中具有重要的实用价值。

Simplified Method of Simulating Double-Layer Micro-Perforated Panel Structure

The micro-perforated panel(MPP)structure has been widely used in various noise control applications,and thus its acoustic performance prediction has been receiving increasing attention.The acoustic performance of simple MPP structures,such as a MPPsound absorber,has been predicted using an analytical calculation method.However,this is not a suitable approach toward predicting the acoustic performance of complicated MPP structures,owing to the structural complexity of these structures.Moreover,the many perforations of submillimeter scale diameter render the MPP structures very difficult to analyze using numerical simulation.Thus,this study focused on two different simplified MPP simulation methods:the transfer admittance method and the equivalent fluid method,and their application on double-layer MPP structures.Based on the two simplified MPP simulation methods,the transmission loss value of the double-layer MPP mufflers with two sets of different structural parameters was calculated,respectively.The predicted results were compared with the impedance tube measurements.The results revealed that the two simplified MPP simulation methods could effectively predict the acoustic performance of doublelayer MPP structures.Moreover,the prediction based on the transfer admittance method can outperform the two simplified simulation methods.

福溪水库泄放洞改造金属结构布置与设计

福溪水库为提升防洪能力,将原导流洞改建为泄放洞作为汛期预泄设施。主要介绍该水库泄放洞改造工程金属结构设备的总体布置和具体设计,并从设备布置、结构设计、启闭机选型等方面进行阐述,工程的金属结构在确保结构强度、刚度及稳定性的前提下均能符合现行规范要求。

高速破片侵彻舰船双层横舱壁结构研究

反舰导弹战斗部爆炸产生的高速破片会对舰船内部人员、武器设备等造成严重毁伤。为研究舰船防护结构的抗侵彻性能,在传统加筋板架舱壁结构的基础上提出一种双层平板舱壁结构,对高速破片侵彻薄板的理论和经验公式进行分析,验证计算方法的可行性;对两者在高速破片侵彻载荷作用下的失效特性、动态响应以及吸能情况进行比较分析,双层舱壁结构抗侵彻性能明显优于传统单层结构;对不同侵彻速度、不同舱壁板厚对双层舱壁结构性能的影响进行研究,和试验数据结果对比,计算结果与之相吻合,并给出舱壁结构吸能特性的影响参数,为双层舱壁结构进行优化设计提供参考。