Comparison of electrochemical properties of atmospheric pressure plasma coatings for Al_2O_3-3TiO_2 and CoNiCrAlY in sea water

To improve the durability of underwater rotating products,the corrosion characteristics in harsh marine environment were evaluated through various electrochemical experiments on the Al2O3-3TiO2 and CoNiCrAlY coating layers by atmospheric pressure plasma spray coating process.By evaluating the corrosion resistance of these materials,their applicability to environmentally friendly power generation equipment such as blades of tidal current turbines was examined.According to the Tafel analysis for micro-areas including the coating layer,the coating/metal interlayer and the base metal,the Al2O3-3TiO2 coating layer and the CoNiCrAlY coating layer show markedly lower corrosion current density than the base metal.The corrosion current density of the CoNiCrAlY coating layer (9.75316×10-8A/cm2) is about 1.6 times more than that of the Al2O3-3TiO2 coating layer (6.13139×10-8A/cm2).

X-ray diffraction study of effect of deposition conditions on α-β phase transition and stress evolution in sputter-deposited W coatings

Pure W and W-Cu-W trilayer coatings were deposited on an Fe substrate by d.c. magnetron sputtering. The α-β phase evolution, intragranular stress evolution in sputter-deposited W layer were investigated by x-ray diffraction. They are directly related to the film microstructure, density and adhesion. Therefore, control of the film stress and phase component transition is essential for its applications. The phase component transition from β-W to α-W and intragranular stress evolution from tensile to compressive strongly depend on the deposition parameters and can be induced by lowering Ar pressure and rising target power. The compressively stressed films with α-W phase have a dense microstructure and high adhesion to Fe substrate.

Influence of Microstructures on Thermal Shock and Sintering Behavior of YSZ-based Thermal Barrier Coatings

In this study, two thermal barrier coatings based on YSZ were produced by using a commercially available agglomerated and sintered powder and a special spray powder prepared by high energy ball milling. Both thermal barrier coatings exhibited similar overall porosities, but significantly different microstructures. Application of the special spray powder prepared by high energy ball milling led to a microstructure with numerous inclusions of semi-molten agglomerates, which introduced a plethora of clusters of fine pores into the coating and several more microstructural defects. This microstructure resulted in a significantly better thermal shock behavior compared to the conventional thermal barrier coating. The heat treatment of both thermal barrier coatings atθ=1150℃for t=100 h led to a sintering of both coatings. The results were reduced overall porosity and significantly increased fracture toughness. A correlation between the fracture toughness of both coatings after the heat treatment and the thermal shock life time could not be identified.

Ang-1/Tie2在大鼠体-肺分流肺动脉高压形成中的作用

【目的】探讨Ang-1及其受体Tie2在体-肺分流肺动脉高压形成过程中的作用。【方法】分流组20只大鼠行左颈总动脉-左颈外静脉分流手术,对照组16只大鼠行假手术。分别于术后4周和8周测量右心室收缩压,并对大鼠肺组织进行组织学分析,测量肺微细动脉壁厚度指数。通过实时荧光定量RT-PCR和Western Blot的方法,检测大鼠肺组织中Ang-1和Tie2的表达。同时,通过Western Blot检测caspase-3及激活型caspase-3的表达。【结果】与对照组相比,分流组大鼠术后第4周和第8周右心室收缩压明显升高。组织学分析发现,分流组大鼠肺微细动脉内膜内皮细胞增生肥大,血管壁厚度指数增加。在分流引起肺动脉高压形成的过程中,Ang-1和Tie2在mRNA及蛋白水平上均明显增加。与此同时,标志细胞调亡的激活型caspase-3的表达却明显下降。【结论】Ang-1和Tie2的表达与肺动脉高压紧密相关。Ang-1/Tie2系统可能通过抑制内皮细胞凋亡,促进体-肺分流肺动脉高压的形成。

TIE47-3A型假负载在短波广播发射机中的应用

假负载的最基本要求是阻抗匹配和所能承受的功率。文中给出了选用TIE47-3A型假负载来匹配500kW功率的发射机的实现方案,并对其技术参数、设计与操作方式、安装以及调试方法进行了说明。

Structure of Micro-nano WC-10Co4Cr Coating and Cavitation Erosion Resistance in NaCl Solution

Cavitation erosion （CE） is the predominant cause for the failure of overflow components in fluid machinery. Advanced coatings have provided an effective solution to cavitation erosion due to the rapid development of surface engineering techniques. However, the influence of coating structures on CE resistance has not been sys- tematically studied. To better understand their relationship, micro-nano and conventional WC-10Co4Cr cermet coat- ings are deposited by high velocity oxygen fuel spray- ing（HVOF）, and their microstructures are analyzed by OM, SEM and XRD. Meanwhile, characterizations of mechan- ical and electrochemical properties of the coatings are carried out, as well as the coatings＇ resistance to CE in 3.5 wt % NaC1 solution, and the cavitation mechanisms are explored. Results show that micro-nano WC-10Co4Cr coating possesses dense microstructure, excellent mechanical and electrochemical properties, with very low porosity of 0.26 4-0.07% and extraordinary fracture toughness of 5.58 4-0.51 MPa.m1/2. Moreover, the CE resistance of micro-nano coating is enhanced above 50% than conventional coating at the steady CE period in 3.5 wt % NaC1 solution. The superior CE resistance of micro- nano WC-10Co4Cr coating may originate from the unique micro-nano structure and properties, which can effectively obstruct the formation and propagation of CE crack. Thus,a new method is proposed to enhance the CE resistance of WC-10Co4Cr coating by manipulating the microstructure.

Transient liquid assisted nucleation mechanism of YBa_2Cu_3O_(7-δ) in coated conductor films derived by BaF_2 process

It is significant for low-cost preparation of YBa2Cu3O7-δ（YBCO） coated conductors to make clear the mechanism of orientation, copper segregation, and nucleation density in BaF2-derived YBCO crystallization. In the present work,a distinct nucleation mechanism was proposed based on a transient liquid phase induced by the size effect as well as near-equilibrium assumption. With this scheme the nucleation of YBCO prepared by metal–organic deposition（MOD） or the physical vapor deposition BaF2 process was semi-quantitatively analyzed, revealing that the direct driving force for nucleation is YBCO supersaturation in the liquid phase. The theoretical analysis on the nucleation orientation portion is evidenced by the experimental result.

Protection Performance of Plasma Sprayed Al_(2)O_(3)-13 wt%TiO_(2) Coating Sealed with an Organic-inorganic Hybrid Agent

An organic-inorganic hybrid sealing agent was fabricated and used in the plasma sprayed Al_(2)O_(3)-13 wt%TiO_(2)coating,and conventional silicone agent was also used for comparison.Protection performance of the coatings was comprehensively evaluated based on both anti-corrosion and anti-biofouling properties.The results reveal that the sealing treatment is remarkably useful to decrease the porosity of the coating,and the porosity of the coating sealed with the hybrid agent is only 0.035%.Immersion corrosion test and Tafel polarization test reveal that the sealed coating with the hybrid agent exhibits a better corrosion resistance by compared with the coating sealed with silicone agent.The corrosion current density i_(corr) of the hybrid agent sealed coating is only 0.7×10^(-6)A·cm^(-2).Moreover,anti-biofouling tests both in the outdoor analogue hydraulic environment and in the natural marine environment prove that the mentioned novel coating presents a better combination of corrosion resistance and anti-biofouling property by compared with the other coatings,and it could be used as a protection of metal components in the marine environment.

The Influence of Ceramic Coating on Fatigue Crack Growth Behaviour of X17CrNi15-2 Stainless Steel

Fatigue crack growth tests were carried out on the SEN B3 precracked specimens, with dimensions in accordance with ISO 12108 requirements. The specimens were made of martensitic stainless steel, X17CrNi15-2, and some of them were modified by the ceramic coating deposition surface treatment. The effects of ceramic coating, on the fatigue crack growth behaviour of hollow shaft specimens, were experimentally investigated. Fatigue crack growth rates, da/dN, were characterised, using the power law relationship between da/dN (in mm/cycle) and the stress intensity factor range, ΔK (in MPa∙m0.5). The two constants of the correlation are 7.9768 × 10−9 and 2.8107 for the parent material, and those for the coated material are 2.4391 × 10−9 and 3.1990, respectively. Microstructural analyses were carried out on the tested specimens, which shows that the maximum hardness of the ceramic coating is higher than that of substrate by a factor of ~3.2. The dimple fracture dominates the final fracture mechanism for the parent material, and the combination of fatigue, ductile fracture and cleavage dominates the final fracture mechanism for the coated material, based on the SEM analyses. EDS tests’ results reveal that the parent material specimen shows higher levels of C at matrix regions along with Fe- and O-rich regions, compared with the coated material specimen.

Self - Crosslinking Behavior of Self - Emulsion Water - Based Polyure-thane Coating Agents

The relation between structures and properties of polyurethane are investigated by modern physical and chemical methods.The results obtained are as follows:the effects of the content of self-crosslinking agent on the properties of polyurethane,i.e.,dispersion stability,dynamical viscoelasticity and mechanical properties are discussed.It is found that the optimum molar ratio of epichlorohydrin and diethylenetriamine is 1:2.A mois-

Coating Resistant Refractory Castables YB/T 4193-20091

1 Scope This standard specifies the term, definition, classification, technical requirements, test methods, quality appraisal procedures, packing, marking, transportation, storage, and quality certificate of coating resistant refractory eastables.

Microstructural Characteristics and Wear Performance of Plasma Sprayed Al_2O_3-13 wt. % TiO_2 Coating on the Surface of Extrusion Wheel

The conventional Al2O3-13 wt. % TiO2 composite ceramic coatings are fabricated by plasma spraying on the surface of extrusion wheel. The microstrueture, morphology and phase compositions of the substrate and coat- ing are investigated by using X-ray diffractometry （XRD） , scanning electron microsopy （SEM） and energy dis- persive spectroscopy （EDS）. Moreover, the microhardness of the substrate and the coating are investigated using Vickers mierohardness tester, the friction and wear behaviors of the substrate and the coating are investigated by using a block-on-ring tribometer under dry sliding conditions with the load of 245 N. The results show that both γ-Al2O3 and α-Al2O3 phases are observed in the as-sprayed coatings, the mian phase is γ-Al2O3. There are white particulates Al2O3 on its surface. The Al2O3-13 wt. % TiO2 coating possesses higher mierohardness which is about 1018HV and 1.6 times that of the substrate. The wear performance of coating is better than that of the substrate. In a practical application, the life of the extrusion wheel which is plasma sprayed Al2O3-13 wt. % TiO2 coating on the surface is 1.2 times that of the conventional extrusion wheel, and the life is about 330 h.

Finite Element Simulation of the Polymeric Liquid Flow in Coat-hanger Die

A three - dimenslonal finite element model is developed to deal with the polymeric liquid flow in coat - hanger die. This model is used to predict the flow behavior of the 2％ CMC/watsr solution in the coat - hanger die with linearly taper manifolds and its validity is experimentally verified quantitatively and qualitatively by using Laser Doppler Velocimetry and Particle Image Velocimetry respectively.

Tie2基因过表达对单核细胞功能的影响

目的:探讨过表达Tie2基因后单核细胞功能的变化及对内皮细胞增殖、迁移、小管形成的影响,初步研究TEMs(Tie2-expressing monocytes)促血管生成的机制。方法:建立过表达Tie2单核细胞系,荧光倒置显微镜下观察U937细胞的感染情况,RT-PCR、Western blot分别检测感染后U937细胞Tie2 mRNA和蛋白水平的表达情况;实时定量PCR检测感染后空载组NC-L.V-U937和实验组TEK-L.V-U937细胞mRNA水平表达的差异;ELISA检测NC-L.V-U937和TEK-L.V-U937细胞上清中细胞因子分泌的异同;增殖、迁移、小管形成实验分别观察TEK-L.V-U937细胞对内皮细胞增殖、迁移、小管形成的影响。结果:首次建立了转染Tie2基因的单核细胞系;RT-PCR及Western blot结果显示,与空载组NC-L.V-U937细胞相比,实验组TEK-L.V-U937细胞在mRNA和蛋白水平Tie2的表达显著增加,而NC-L.V-U937细胞几乎不表达Tie2;Real time-PCR结果显示,TEK-L.V-U937细胞IL-8的表达较空载组显著增加(P<0.01),IL-10的表达也有所上升(P>0.05);与空载组相比,TEK-L.V-U937细胞IL-8蛋白分泌明显增多(P<0.05),VEGFA蛋白分泌量也有上升的趋势(P>0.05),但两组细胞几乎都无EGF的分泌;TEK-L.V-U937的条件培养基刺激内皮细胞形成的小管数较多,IL-8中和抗体能抑制内皮小管的形成;NC-L.V-U937、TEK-L.V-U937饥饿培养上清对内皮细胞的迁移作用不明显(P>0.05);增殖的第3天,与空载组相比,TEK-L.VU937的条件培养基能显著地引起内皮细胞的增殖(P<0.05)。结论:过表达Tie2基因后显著地增加U937单核细胞系IL-8的表达,并进一步促进了内皮细胞的增殖与小管形成。

裂解气相色谱-质谱法分离鉴定聚氨酯防水涂料中的煤焦油

建立了采用闪蒸裂解气相色谱-质谱测定固化后的聚氨酯防水涂料中的煤焦油的新方法。该方法方便快捷,无需对样品进行前处理,而且测定结果不受聚氨酯组分的干扰。该方法在建筑材料中有毒有害组分的分析检测方面有一定的应用价值。

自制苯乙烯-丙烯酸乙酯共聚物与PEG20M复合萃取涂层用于洗涤制品中1,4-二氧杂环己烷的测定

采用顶空固相微萃取-毛细管气相色谱联用技术测定了洗涤制品中的1,4-二氧杂环己烷。使用自制的萃取头(苯乙烯-丙烯酸乙酯共聚物与PEG20M复合)于顶空平衡温度80℃下萃取样品40min。萃取物用内壁涂有SE-30固定液的石英毛细管柱分离,外标法定量。1,4-二氧杂环己烷含量为0.35-120μg/g时,其峰面积与含量呈良好的线性关系(r=0.999 8);回收率为98.7%-102%;相对标准偏差(n=5)为9.33%。

英夫利昔单抗治疗银屑病后皮损中内皮激活的消退及Tie2受体的下调

Background: Psoriasis is a common dermatosis characterized by erythematous skin plaques and associated arthritis. Microvessels of the papillary dermis in psoriatic lesions are elongated, tortuous, and dilated, which contributes significantly to the proinflammatory response. Angiopoietin (Ang) 1 and 2 and their receptor, Tie2, are a family of growth factors recognized in inflammatory lesions to be critical for new blood vessel growth and maintenance, with recent studies suggesting tumor necrosis factor (TNF)-α -induced angiogenesis is in partmediated by the Tie2 receptor. The aim of this study was to evaluate the effect of anti-TNF-α therapy on angiogenic growth factor expression and on the cellular infiltrate in psoriatic lesional skin. Methods: Sixteen patients with moderate to severe psoriasis and associated psoriatic arthritis (n = 13) received infliximab infusions (3- 5 mg/kg) at baseline and at 2 and 6 weeks. Clinical assessments and skin biopsies were undertaken at baseline, and at 2 and 12 weeks. Ang 1,Ang 2, Tie2, and TNF-α messenger RNA expression were quantified by real-time polymerase chain reaction. Protein expression of vascular endothelial growth factor, Ang 2, Tie2, TNF-α , and the inflammatory infiltrate was determined using immunohistology. We conducted clinical assessments including Psoriasis Area and Severity Index, percentage body surface area, Arthritis Disease Activity Score, and Health Assessment Questionnaire. Results: At baseline expression of Ang 1/2, vascular endothelial growth factor, Tie2, and TNF-α messenger RNA and protein were greater in preinvolved skin compared with uninvolved skin (P < .05). Infliximab produced a significant reduction in protein expression of Ang 2, vascular endothelial growth factor, and Tie2 (P < .001) along with a decrease in messenger RNA expression of Ang 1 (P < .045) and Tie2 (P < .021). This was paralleled by a significant reduction in the inflammatory infiltrate scores (P < .001) and platelet-endothelial cell adhesion molecule (CD31) expression (P = .001), suggesting deactivation of endothelial cell. There was a 93% mean reduction in Psoriasis Area and Severity Index (P = .001), and a significant reduction in Disease Activity Score 28 (P = .012) and mean Health Assessment Questionnaire scores by week 12. Limitations: This study involves a small number of patients. Conclusion: These results suggest infliximab is both effective and well tolerated in severe psoriasis, resulting in deactivation of endothelium and down-regulation of growth factor and cytokine expression, leading to a decrease in the cellular infiltrate and clinical improvement in psoriasis. Furthermore, the effect of infliximab on growth factor expression, in particular Tie2, supports previous in vitro work suggesting TNF-α may be a major regulator of the Ang/Tie2 pathway.

靶向血管生成素/酪氨酸蛋白激酶-2(Ang/Tie2)通路的脓毒症治疗药物的研究进展

脓毒症是一种由细菌等病原微生物侵入机体引起的全身炎症反应综合征,常伴有器官功能障碍、组织灌注不良、低血压甚至脓毒性休克。血管功能障碍与脓毒症之间存在明确的关系。血管生成素/酪氨酸蛋白激酶-2(Ang/Tie2)通路可以作为控制炎症、防止血管渗漏药物研发的重要靶点,为脓毒症治疗提供新的可能性。靶向Ang/Tie2通路的脓毒症治疗药物有重组人Ang1腺病毒、Ang1类似物、Ang2抑制剂、重组人Ang2和Tie2激动剂。总结了靶向Ang/Tie2通路的脓毒症治疗药物的研究进展,以期为脓毒症治疗药物的开发提供思路。

Processing of a low-costγ-γ'NiPtAl coating with improved oxidation resistance

A novelγ-γ'(Ni solid solution—Ni_(3)Al)NiPtAl coating was produced on advanced single-crystal(SC)superalloy N5 by electroplating of a thin Pt coating with~3μm in thickness followed by heat treatment at 1000℃in vacuum.For comparison,a traditionalγ-γ'NiPtAl coating was also produced by electroplating of a thick Pt coating with~6μm in thickness followed by heat treatment at 1100℃in vacuum.The novel coating has a mass gain of~0.5 mg·cm^(-2)after 100 h 1-h cyclic oxidation at 1150℃,showing better oxidation resistance than the traditional coating.An oxide scale mostly consisting ofα-Al_(2)O_(3)grew on the novel coating because the element Cr from the SC alloy substrate contributes to the formation ofα-Al_(2)O_(3).Pt content in the novel coating has significant effect on the oxidation resistance.The optimized Pt content in the coating is about 16 at%,which is helpful to reduce the diffusion of harmful elements from the substrate into the coating but also to reduce the cost of the coating.

环氧改性丙烯酸树脂的合成及其与防腐防污涂层连接性能的研究

以甲基丙烯酸缩水甘油醚(GMA)、丙烯酸甲酯(MMA)和丙烯酸丁酯(BA)为原料,通过聚合反应合成了环氧改性丙烯酸树脂,并采用红外光谱(FTIR)、核磁共振氢谱(^(1)H-NMR)进行了表征。通过接触角、附着力等测试对环氧改性丙烯酸连接漆与防腐防污涂层连接性能进行了研究。结果表明,环氧改性丙烯酸树脂合成最佳反应温度为80℃,保温时间为7 h。自制的环氧改性丙烯酸连接漆与防腐防污涂层具有优异的附着力。