Corrosion behavior of 2A97 Al-Cu-Li alloys in different thermomechanical conditions by quasi-in-situ analysis

As a promising material in the aircraft industry,2A97 Al-Cu-Li alloy exhibits high corrosion susceptibility that may limit its application.In the present work,to illustrate the influences of precipitate and grain-stored energy on localized corrosion evolution in 2A97 Al-Cu-Li alloy,cold working and artificial aging were carried out to produce 2A97 Al-Cu-Li alloys under different thermomechanical conditions.Quasi-in-situ analysis,traditional immersion test and electrochemical measurement were then conducted to examine the corrosion behavior of 2A97 alloys.It is revealed that precipitate significantly affects Cu enrichment at corrosion fronts,which determines corrosion susceptibility of alloys,whereas grain-stored energy distribution is closely associated with localized corrosion propagation.It is also indicated that quasi-in-situ analysis exhibits a consistent corrosion evolution with traditional immersion tests,which is regarded as a proper method to explore localized corrosion mechanisms by providing local microstructural information with enhanced time and spatial resolutions.

In-situ stabilisation followed by ex-situ composting for treatment and disposal of heavy metals polluted sediments

An innovative in-situ stabilisation treatment followed by ex-situ sediment composting was tested for its ability to treat and dispose of heavy-metal-polluted sediments in a river near the Chinese Pearl Delta. First, polluted sediments were treated in-situ to stabilise the heavy metals. Then the treated sediments were dredged, dewatered and sent for high temperature aerobic composting （HTAC） treatment. Finally, the compost products were used as a fertiliser for fiver bank plants. The stabilisation efficiency of heavy metals during the process was investigated and the results are as follows： （1） using in-situ stabilisation, the extraction concentrations of Cu, Zn and Pb were reduced by 65.0%, 82.2% and 90.0%, respectively, which are much lower than the national standard given in the Identification Standard for Hazardous Waste （GB5085.3-1996）; （2） chemical fraction analysis showed that heavy metals were further stabilized during the HTAC treatment; （3） the concentrations of Cu, Zn and Pb in rainwater leachate through the river bank met the level of class V in the Environmental Quality Standards for Surface Water in China （GB3838-2002）. Therefore, using this new process, the toxicities of heavy metals in sediments were reduced markedly.

Engineering application of ecological remediation technologies in situ treatment of black-odour river

In order to study the remediation technology and effect of the black-odour water bodies,the treatment project of typical black-odour river was taken as an example,and the technical measures,such as sediment dredging,aeration,adding microbial preparation and constructing ecological floating bed,were adopted to treat and restore the water body.The results showed that the black and odorous phenomenon of the river had been basically eliminated and the water quality had been significantly improved after the 9-week operation.The highest removal rates of COD,NH3-N and TP were 82.5%,77.6%and 81.4%,respectively,and the water quality was improved from inferior class V to class IV.The engineering practice indicated that the technical scheme was feasible and could effectively remove the pollutants such as organic matters,ammonia nitrogen and total phosphorus in the water,which could provide basis and reference for the treatment project of similar black-odour water body.

Chromosome analysis of esophageal squamous cell carcinoma cell line KYSE 410-4 by repetitive multicolor fluorescence in situ hybridization

Chromosome aberrations are distinctive features of human malignant tumors. Analysis of chromosomal changes can illuminate the molecular mechanisms underlying the development and progression of cancer. To establish the technique of multicolor fluorescence in situ hybridization （M-FISH） for identifying chromosome aberrations in esophageal carcinoma cell line KYSE 410-4, four pools of 6-color whole-chromosome painting probes have been designed and hybridized on the same metaphase spread by four rounds of repetitive FISH. Repetitive 6-color M-FISH was successfully established and the cytogenetic abnormalities in KYSE 410-4 cells were characterized. Chromosome gains occurred at 2q, 3, 8, 17p, and X. An isochromosome 3q was visualized in the cell line, which might be one intermediate mechanism leading to 3p losses and/or 3q gains. Furthermore, 16 structural arrangements were detected, including four derivative chromosomes. The rearrangement of the centromeric regions accounted for approximately 44% of all rearrangements. The results added a more complete and accurate information of the genetic alterations to the classical cytogenetic description of KYSE 410-4 and provided a detailed cytogenetic background data for appropriate use of the cell line. The established 6-color M-FISH was useful for analyzing chromosomes in the whole genome of human tumors.

Effect of alloying elements on mechanical properties in Cu-15%Cr in-situ composites

The effects of alloying elements on the mechanical properties as well as electrical conductivity in Cu-15%Cr(mass fraction) in-situ composites were systematically studied and high strength and high electrical conductive Cu base in-situ composites have been developed. The best combination is the addition of 0.1% to 0.2% Zr, Ti, or Sn in Cu-15%Cr in-situ composite, thermomechanical treatment to refine the microstructure and optimizing the precipitation of second phase. The strength is controlled by high density of dislocations in the Cu matrix, the lamellar spacing of the second phase, and the fine Cr precipitates. The aging treatment to reduce solute atoms has a beneficial effect on the increase of electrical conductivity. The addition of Zr, or Ti of about 0.15% to 0.2% promotes the precipitation of Cr particles.

Enhanced strengthening by two-step progressive solution and aging treatment in AM50-4%(Zn,Y) magnesium alloy

AM50-4%(Zn,Y)alloy with a Zn/Y mole ratio of6:1was subjected to thermal analysis,and the results were used for designing a two-step progressive solution treatment process.The effects of solution and aging treatments on the microstructure and mechanical properties of the AM50-4%(Zn,Y)alloy were investigated using OM,XRD,SEM/EDS,TEM,tensile test and hardness test.The experimental results demonstrated that the two-step progressive solution treatment could make theΦandβphases sufficiently dissolve into the matrix which possessed higher supersaturated degree of the dissolved solute compared with the one-step solution treatment.This resulted in a certain enhancement of the precipitation strengthening effect during the subsequent aging process.The precipitation of theФphase had a greater impact on the comprehensive mechanical properties of the alloy thanβphase precipitation when the aging treatment was performed at180℃.The peak aging strength of the AM50-4%(Zn,Y)alloy which was subjected to the two-step progressive solution treatment process(345℃for16h and375℃for6h)was obtained after the aging treatment at180℃for12h.

Towards optimal treatment of ductal carcinoma in situ

Ductal carcinoma in situ(DCIS) is a non-obligate precursor of invasive breast cancer with a variable biological behavior which is difficult to accurately predict using the current clinico-pathological parameters. Randomized controlled trials have demonstrated that adjuvant radiotherapy(RT) reduces the risk of local recurrence after adequate local excision of DCIS. Tamoxifen may be considered as an adjuvant endocrine treatment in patients with high risk estrogen receptor positive disease. There is however a growing consensus that RT can be safely omitted in a subgroup of patients with favorable biological features in order to avoid overtreatment. The sentinel node biopsy is not routinely indicated but should be considered in women undergoing mastectomy for DCIS. The discovery of molecular signatures that accurately predict the biological behavior of this common malignancy will facilitate a personalized treatment approach in the future.

MicroRNA-502-3p regulates GABAergic synapse function in hippocampal neurons

Gamma-aminobutyric acid(GABA)ergic neurons,the most abundant inhibitory neurons in the human brain,have been found to be reduced in many neurological disorders,including Alzheimer's disease and Alzheimer's disease-related dementia.Our previous study identified the upregulation of microRNA-502-3p(miR-502-3p)and downregulation of GABA type A receptor subunitα-1 in Alzheimer's disease synapses.This study investigated a new molecular relationship between miR-502-3p and GABAergic synapse function.In vitro studies were perfo rmed using the mouse hippocampal neuronal cell line HT22 and miR-502-3p agomiRs and antagomiRs.In silico analysis identified multiple binding sites of miR-502-3p at GABA type A receptor subunitα-1 mRNA.Luciferase assay confirmed that miR-502-3p targets the GABA type A receptor subunitα-1 gene and suppresses the luciferase activity.Furthermore,quantitative reve rse transcription-polymerase chain reaction,miRNA in situ hybridization,immunoblotting,and immunostaining analysis confirmed that overexpression of miR-502-3p reduced the GABA type A receptor subunitα-1 level,while suppression of miR-502-3p increased the level of GABA type A receptor subunitα-1 protein.Notably,as a result of the overexpression of miR-502-3p,cell viability was found to be reduced,and the population of necrotic cells was found to be increased.The whole cell patch-clamp analysis of human-GABA receptor A-α1/β3/γ2L human embryonic kidney(HEK)recombinant cell line also showed that overexpression of miR-502-3p reduced the GABA current and overall GABA function,suggesting a negative correlation between miR-502-3p levels and GABAergic synapse function.Additionally,the levels of proteins associated with Alzheimer s disease were high with miR-502-3p overexpression and reduced with miR-502-3p suppression.The present study provides insight into the molecular mechanism of regulation of GABAergic synapses by miR-502-3p.We propose that micro-RNA,in particular miR-502-3p,could be a potential therapeutic to rget to modulate GABAergic synapse function in neurological disorders,including Alzheimer's disease and Alzheimer's diseaserelated dementia.

Suggested Strategies in Water Treatment by Using Situ Pressure in Reverse Osmosis

Nowadays desalination is one of the main resources to obtain water in many areas. The most advanced method for water filtration is reverse osmosis. In this system, water is injected into semi-membranes by using power pumping, and its salt water is taken away from the solution. This paper has tried to offer guidelines to use the pressure created?in situ?of harvesting water, instead of utilizing power pump, which produces the necessary pressure for the reverse osmosis. These guidelines have been divided into 2 main groups: Using the created natural pressure, and the other way is using the pressures that are caused by the constructions built for harvesting water.

Melt Treatment of Al-7%Si Alloy by Flux Injection

The melt treatment of A1-7%Si alloy by the flux injection method in a resistance furnance was investigated. The experimental results show that the flux injection method can realize the melt treatment of A1-7%Si alloy. In purification, the flux injection method is superior to the standard lance degassing method. For the injection flux, the purifier Na2SiF6 is more powerful than Na3A1F6, the modifiers SrCl2, and R.E. Cl3 are quick acting, like NaF, but less powerful, the grain refiner containing K2TiF6 and KBF4 with Ti/B=1 is more potent than that with Ti/B=5. The analytical results indicate that the mass-transfer rate for the flux injection method is much higher than that for the conventional method .

Heat Treatment of Nd_(1+x)Ba_(2-x)Cu_3O_(7-δ) Superconductors

Two kinds of Nd 1+ x Ba 2- x Cu 3O 7- δ , the sintered samples and zone melted samples, were treated in pure Ar at 950 ℃. The substitution of Nd ions for Ba ions in the Nd 1+ x Ba 2- x Cu 3O 7- δ before and after the heat treatment was investigated by XRD. In order to know the effects of heat treatment, the T c and J c of samples with and without the heat treatment in Ar were comparatively studied. The results show that the substitution of Nd for Ba decreases, whereas T c and J c increase after the treatment. The Nd 1+ x Ba 2- x Cu 3O 7- δ samples were oxygenated in pure oxygen at 300 ℃ . Based on the XRD spectra it was found that the samples with x <0.4 can transform from tetragonal phase into orthorhombic phase after the oxygenation, whereas in the sample with x >0.4 no phase transition occurs even after a long time oxygenation.

Effect of Heat Treatment on Mechanical Properties and Microstructure of NST 37-2 Steel

Engineering materials, mostly steel, are heat treated under controlled sequence of heating and cooling to alter their physical and mechanical properties to meet desired engineering applications. In this study, the effect of heat treatment (annealing, normalising, hardening, and tempering) on the microstructure and some selected mechanical properties of NST 37-2 steel were studied. Sample of steel was purchased from local market and the spectrometry analysis was carried out. The steel samples were heat treated in an electric furnace at different temperature levels and holding times;and then cooled in different media. The mechanical properties (tensile yield strength, ultimate tensile strength, Young’s modulus, percentage reduction, percentage elongation, toughness and hardness) of the treated and untreated samples were determined using standard methods and the microstructure of the samples was examined using metallographic microscope equipped with camera. Results showed that the mechanical properties of NST 37-2 steel can be changed and improved by various heat treatments for a particular application. It was also found that the annealed samples with mainly ferrite structure gave the lowest tensile strength and hardness value and highest ductility and toughness value while hardened sample which comprise martensite gave the highest tensile strength and hardness value and lowest ductility and toughness value.

Interferon-free treatments in patients with hepatitis C genotype 1-4 infections in a real-world setting

AIM To investigated the real-world effectiveness and safety of various regimens of interferon-free treatments in patients infected with hepatitis C virus(HCV).METHODS We performed an observational study to analyze different antiviral treatments administered to 462 HCV-infected patients, of which 56.7% had liver cirrhosis. HCV RNA after 4 wk of treatment and at 12 wk after treatment sustained virologic response(SVR) as well as serious adverse events(SAEs) was analyzed first for the whole cohort and then separately in patients who met or did not meet the inclusion criteria of a clinical trial(CT-met and CT-unmet, respectively).RESULTS The most frequently prescribed treatment was simeprevir/sofosbuvir(36.4%), followed by sofosbuvir/ledipasvir(24.9%) and ombitasvir/paritaprevir/ritonavir(r)/dasabuvir(19.9%). Ribavirin(RBV) was administered in 198 patients(42.9%). SVRs occurred in 437/462 patients(94.6%). The SVRs ranged between 93.3% and 100% for genotypes 1-4. SVRs were achieved in 96.2% patients in the CTmet group vs 91.9% patients in the CT-unmet group(P = 0.049). Undetectable HCV RNA at week 4 occurred in 72.9% of the patients. In the univariate analysis, the factors associated with SVRs were lower liver stiffness, absence of cirrhosis, higher platelet count, higher albumin levels, no RBV dose reduction, undetectable HCV RNA at week 4 and CT-met group. In the multivariate analysis, only albumin was an independent predictor of treatment failure(P = 0.04). Eleven patients(2.4%) developed SAEs; 5.2% and 0.7% of the patients in the CT-unmet and CT-met groups, respectively(P = 0.003).CONCLUSION A high proportion of patients with HCV infection achieved SVRs. For patients who did not meet the CT criteria, treatment regimens must be optimized.

一种原位合成高导热S-BN方法的探究

随着科技的飞速发展,为减少因电力电子设备内部热量积蓄造成设备安全隐患,高导热热界面材料受到研究人员的广泛关注。球形氮化硼(S-BN)不仅保持了氮化硼原有的优良性能,而且还具有颗粒度良好,比表面积高等优点,实现了高填充、高导热的优良性能。本文主要探究了一种通过选取合理的硼源、氮源原位合成高导热球形氮化硼材料的方法。

Effect of two-step solid solution on microstructure andδphase precipitation of Inconel 718 alloy

Inconel 718 is the most popular nickel-based superalloy and is extensively used in aerospace,automotive,and energy indus-tries owing to its extraordinary thermomechanical properties.The effects of different two-step solid solution treatments on microstructure andδphase precipitation of Inconel 718 alloy were studied,and the transformation mechanism fromγ″metastable phase toδphase was clarified.The precipitates were statistically analyzed by X-ray diffractometry.The results show that theδphase content firstly increased,and then decreased with the temperature of the second-step solid solution.The changes in microstructure andδphase were studied by scanning electron microscopy and transmission electron microscopy.An intragranularδphase formed in Inconel 718 alloy at the second-[100]_(δ)[011]γ step solid solution temperature of 925℃,and its orientation relationship withγmatrix was determined as//and(010)_(δ)//(111)γ.Furthermore,the Vickers hardness of different heat treatment samples was measured,and the sample treated by second-step solid solution at 1010℃ reached the maximum hardness of HV 446.84.

基于E-H_(2)O_(2)-O_(3)氧化—BAC滤池工艺的印染废水深度处理应用研究

采用电化学原位合成法制备H_(2)O_(2)(E-H_(2)O_(2))并耦合O_(3)形成了E-H_(2)O_(2)-O_(3)高级氧化技术,并以该技术为核心,采用E-H_(2)O_(2)-O_(3)氧化—BAC(生物活性炭)滤池工艺在中试条件下对印染废水生化出水进行深度处理。E-H_(2)O_(2)-O_(3)氧化的最优工艺参数为O_(3)通入量120 g/h、H_(2)O_(2)浓度0.63 mmol/L、HRT 2.0 h。中试装置在该条件下连续运行31 d(BAC接触时间40 min),COD、UV_(254)、色度的平均去除率分别达56.4%,89.5%,89.3%,运行成本约为3.35元/t(以废水计)。当进水COD小于90 mg/L时,出水COD低于40 mg/L,达到地表水Ⅴ类排放标准。经E-H_(2)O_(2)-O_(3)氧化—BAC滤池工艺处理后,氧化出水和BAC出水的总荧光强度较进水分别下降了92.0%和96.3%。

臭氧-活性炭与原位挖潜改造在水厂提标扩容工程中的应用

为响应江苏省政府办公厅关于加强城市基础设施建设和供水安全保障的文件精神,江苏某自来水厂根据原水及出水水质情况结合水厂现状制水工艺,采用了以去除有机物为主要目标的“臭氧-活性炭”深度处理工艺,并对水厂旧系统沉淀池及滤池进行原位挖潜改造。水厂提标扩容工程完成后,出水高锰酸盐指数、浑浊度和氨指标分别降低38.9%、42.1%和40.7%,水厂供水规模提升20%,运行效果达到设计预期,可为类似水厂提标扩容工程提供借鉴。

热处理对原位自生Mg_2Si/Mg-Al基复合材料组织与性能的影响

利用金属型铸造制备了原位自生Mg2Si/Mg-Al基复合材料,研究了热处理对该材料组织与性能的影响。结果表明T4处理改变了Mg2Si/Mg-Al基复合材料中Mg2Si的形貌与分布。随着保温时间的延长,棱状枝晶Mg2Si相发生熔断、球化,最终成为尺寸为10-30μm的颗粒;同时β-Mg17Al12相溶入到α-Mg基体中,在随后的时效过程中发生沉淀析出。由于β-Mg17Al12相的溶解,T4处理会降低该材料的硬度,但随后的时效析出可提高其硬度,415℃×12h固溶处理后175℃×16h(T6)时效,硬度可提高14.9%。热处理过程中棱状枝晶Mg2Si相的粒化可用吉布斯-汤姆逊定理解释。

大变形Cu-10Ag原位纤维复合材料的结构和性能

研究了低Ag含量 (10 % ,质量分数 )的Cu Ag原位纤维复合材料的结构和性能 ,结果表明通过原位复合技术可获得强度 >1.5GPa、导电率 (IACS) >6 5 %的原位纤维复合材料。研究了不同中间热处理温度对材料性能的影响 ,并考察了材料的稳定性 ,结果表明通过控制变形量、调整中间热处理及稳定化热处理规范 ,可以获得具有不同强度和导电率组合的Cu 10Ag原位纤维复合材料。材料在自然时效与低温退火过程中 ,有沉淀强化效应产生 ,但导电率基本保持稳定。

热处理条件下激光原位合成高铌Ti-Al金属间化合物复合涂层的微结构特征

为了提高钛合金的高温抗氧化性能,推动钛合金在高温和复杂工况环境下的进一步工程应用,利用高能激光束作用下Ti、Al、Nb三种元素混合粉末之间的原位反应在BT3-1钛合金表面制备了高温抗氧化的高铌Ti-Al金属间化合物复合涂层。针对原位反应所制备涂层存在的缺陷,通过自行设计的热处理工艺优化了涂层和界面微观组织。借助光学显微镜(OM)、X射线衍射仪(XRD)、扫描电镜(SEM)分析了热处理前后复合涂层的物相结构及显微形貌。结果表明:热处理前的涂层主要由单质Nb、金属间化合物γ-TiAl、α_2-Ti_3Al、Ti_3Al_2等物相组成;热处理后的复合涂层,单质Nb固溶到γ-TiAl和α_2-Ti_3Al中,同时形成了新相Ti_3AlNb_(0.3),涂层近似为γ-TiAl+α_2-Ti_3Al双相层片状等轴晶组织。此外,涂层中并未观察到减弱抗氧化性的单质Nb颗粒和Ti_3Al_2相,Ti、Al、Nb的宏观偏析得以消除,涂层与基材界面位置的气孔和裂纹均以消失,出现了明显的白亮带冶金结合过渡层,涂层组织也更加均匀致密。热处理对提高钛合金表面Nb的合金化程度和改善Ti-Al金属间化合物的高温抗氧化性能起到了显著的促进作用。