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.

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.

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.

Fe/C微电解-Fenton组合工艺处理丁腈橡胶废水

采用Fe/C微电解-Fenton组合工艺处理某石化企业丁腈橡胶废水,考察了单纯微电解单元和Fenton法单元处理废水的主要影响因素,在此基础上对组合工艺进行了条件优化以及处理效果验证。结果表明,在微电解单元,Fe/C(质量比)为3/1、初始pH值为2.00～10.00、反应时间为1 h;在Fenton法单元,氧化剂H2 O2投加量为2.0 mL/L、催化剂Fe2+投加量为0.2 g/L、反应温度为40℃以及反应时间为45 min的条件下,丁腈橡胶废水中化学需氧量的总去除率达50.00%以上,丙烯腈的总去除率达95%以上。与单纯Fenton法相比,要达到同样的处理效果,使用组合工艺,H2O2投加量由3.0 mL/L降至2.0 mL/L,Fe2+的投加量由0.6 g/L降至0.2 g/L。

Fabrication of high-performance PVA/PAN composite pervaporation membranes crosslinked by PMDA for wastewater desalination

The pyromellitic dianhydride（PMDA） crosslinked poly（vinyl alcohol）（PVA） was coated on top of the PAN ultrafiltration membrane to form a PVA/PAN composite PV membranes for wastewater desalination. The composite membranes have high application value in industrial wastewater treatment. By varying the membrane fabrication parameters including the weight percent（wt%） of the PMDA, the crosslink temperature and duration, membrane with the best desalination performance was obtained. The composite membrane with a 2-lm-thick PVA selective layer containing 20 wt% of PMDA and being crosslinked at 100 °C for 2 h showed the highest Na Cl rejection of 99.98% with a water flux of 32.26 L/（m^2 h）at 70 °C using the 35,000 ppm Na Cl aqueous solution as feed. FTIR spectroscopy, wide-angle X-ray diffraction, thermogravimetric analysis and scanning electron microscope have been used to characterize the structures and properties of both the crosslinked PVA dense films and PVA/PAN composite membranes. The effects of the concentrations of PMDA,the crosslinking time and temperature to the membrane water contact angle, swelling degree, salt rejection and water flux were systematically studied.

Usefulness of ω-3 fatty acid supplementation in addition to mesalazine in maintaining remission in pediatric Crohn's disease: A double-blind, randomized, placebo-controlled study

AIM： To assess the value of long-chain w-3 fatty acids （FAs） supplementation in addition to amino-salicylic-acid （5-ASA） in pediatric patients with Crohn＇s disease （CD）. METHODS： Thirty-eight patients （20 males and 18 females, mean age 10.13 years, range 5-16 years） with CD in remission were randomized into two groups and treated for 12 too. Group Ⅰ （18 patients） received 5-ASA （50 mg/kg/d）＋w-3 FAs as triglycerides in gastroresistant capsules, 3 g/d （eicosapentanoic acid, EPA, 400 mg/g, docosahexaenoic acid, DHA, 200 mg/g）. Group Ⅱ （20 patients） received 5-ASA （50 mg/kg/d）＋olive oil placebo capsules. Patients were evaluated for fatty acid incorporation in red blood cell membranes by gas chromatography at baseline 6 and 12 mo after the treatment. RESULTS： The number of patients who relapsed at 1 year was significantly lower in group I than in group Ⅱ （P〈0.001）. Patients in group I had a significant increase in the incorporation of EPA and DHA （P〈0.001） and a decrease in the presence of arachidonic acids. CONCLUSION： Enteric-coated w-3 FAs in addition to treatment with 5-ASA are effective in maintaining remission of pediatric CD.

Change of Ecological Characteristics Due to Decrease of COD/SO_4^(2-) Ratio During Sulfate-reduction

In order to investigate the change of ecological characteristics due to the decrease of COD/SO_4^(2-) ratio during sulfate reduction, continuous-flew tests were conducted in an acidogenic sulfate-reducing reactor with molasses wastewater as sole organic carbon source and sodium snlfate as electron acceptor, and the change of pH value, oxidation reduction potential (ORP), volatile fat acids (VFAs), alkalinity (ALK) and the predominant populations with COD/SO_4^(2-) ratio decreasing from 4.2 to 2.0 were investigated. The experimental results demonstrated that, with decreasing COD/SO_4^(2-) ratio, ORP and ALK increased, pH value decreased, and the proportion of acetic acid in terminal products decreased significantly, and a stable -type microbial community with high COD/SO_4^(2-) ratio was converted into a sub -stable -type one with low COD/SO_4^(2-) ratio.

抗利尿激素不适当分泌综合征(Treatment of the syndrome of inappropriate secretion of antidiuretic hormone)的治疗

抗利尿激素不适当分泌综合征(SIADH)是因多种病理因素引起的抗利尿激素(ADH)分泌异常增多,导致体内水潴留,持续性低钠血症、低渗透压血症、尿呈反常的高渗透压、尿钠排泄增多等现象。由于低钠血症和低血浆渗透压,其临床特征则以脑细胞肿胀(脑水肿)所致中枢神经系统的功能紊乱为主要表现。

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&#8729;m0.5). The two constants of the correlation are 7.9768 × 10&#8722;9 and 2.8107 for the parent material, and those for the coated material are 2.4391 × 10&#8722;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.

Corrosion Resistance of Heat-Treated NST 37-2 Steel in Hydrochloric Acid Solution

Corrosion of metal components constitutes a major challenge in many engineering systems, with appropriate design, proper material selection, and heat treatment as commonly used control strategies. In this study, the corrosion behaviour of heat-treated (annealed, normalised, hardened, and tempered) NST 37-2 steel in three concentrations (1.0, 1.5 and 2.0 M) of hydrochloric acid solution was investigated using weight loss and electrode-potential methods. Results showed that corrosion rate increased with increase in acid concentration. The decreasing order of corrosion resistance was Tempered > Annealed > Normalised > Hardened > Untreated. The surface pictures of the heat-treated and untreated samples showed uniform and pitting corrosion with the latter becoming more pronounced as concentration increased.

THE SCROOPING TREATMENT OF POLYESTER SILKLIKE FIBERS

In this paper the mechanism producing scrooping sound has been discussedtheoretically.It has been recognized that the continuous stick-slip vibrationhaving a certain period and the bigger △E(△E——enery released by stick-slipvibration at one time)are the requisite and surfficient conditions producingscrooping sound.For fiber sample,its surface properties and internal structureare two principal factors influencing scrooping sound. Considering the surface properties of polyester fiber after scrooping treatmentare the synthetic reflection of the properties used treatment reagents and thesurface properties of the fiber,how selecting proper reagents for scroopingtreatment would be the key factor influencing the scrooping effect.Sometreatment solutions having better scrooping effect have been obtained in the paper. In order to cause better scrooping effect,not only the treatment reagent andsurface properties of the fiber,but also the internal structure of the fiber must beconsidered,It has been shown in

中医辨证施护联合金黄散中药涂擦对痛风患者的护理效果

目的探讨中医辨证施护联合金黄散中药涂擦对痛风患者的护理效果及中医症状评分的影响。方法选取2022年4月—2023年11月收治的52例痛风患者为研究对象,采取随机数字表法进行分组,分为对照组、研究组,各26例,其中对照组实施常规护理,研究组在对照组基础上实施中医辨证施护联合金黄散中药涂擦。对比两组中医症候积分、疼痛程度、疼痛持续时间及住院时间。结果干预后,研究组中医症候积分及疼痛视觉模拟量表(VAS)评分均低于对照组(P<0.05);研究组患者疼痛持续时间及住院时间均短于对照组(P<0.05)。结论对痛风患者实施中医辨证施护联合金黄散中药涂擦可取得更为理想的干预效果,能积极改善患者临床症状及减轻疼痛程度,缩短患者疼痛持续时间及住院时间。

Effect of Heat Treatment on Gradient Microstructure and Tensile Property of Laser Powder Bed Fusion Fabricated 15-5 Precipitation Hardening Stainless Steel

This work investigated the gradient microstructure evolution and tensile property of LPBF fabricated 15-5 precipitation hardening stainless steel in post-process direct ageing(DA)and solution treating&ageing(STA).The varied microstructures for austenite and small-sized oxide inclusions at different sample heights in the as-built(AB)condition was generally preserved after DA treatment.However,austenite was almost disappeared,and oxide particle grew significantly after the STA treatment.As a result,the tensile property differences in sample top and bottom for AB and DA conditions did not occur in the STA samples.For the influence of post-process heat treatment,the STA condition had the highest yield strength due to the highest volume fraction of nano-sized Cu precipitates.However,the DA specimen had the highest ultimate tensile strength and elongation owing to the considerable amount of austenite phase and associated transformation induced plasticity effect.

矿区复绿植物猪屎豆种子硬实率与萌发特性的研究

采用不同方法对猪屎豆种子进行处理,并测定了种子的硬实率、吸水率和发芽率。结果表明:猪屎豆种子有较高的硬实率,砂纸摩擦5 min可显著提高种子的吸水率;砂纸摩擦1～7 min均可提高种子的萌发率,摩擦5 min的发芽率达36%,而未摩擦种子发芽率只有11.3%。丙酮处理种子1、2、3、4 h不能提高种子的发芽率,时间越长,种子的发芽率越低;过氧化氢处理对种子的催芽没有显著的效果;摩擦后种子在室温(10～27℃)、15、25、30、35℃条件下均能萌发;光照对种子的萌发没有显著的影响,说明猪屎豆种子是中光种子。

硬实种子摩擦处理试验研究

针对部分牧草种子存在硬实的问题,根据牧草硬实种子的基本特征,设计了种子摩擦处理机;采用一次回归正交试验,分析了影响处理效率的主次因素,并找出了最佳参数组合;通过回归正交设计,得到了以处理效率Y为试验目标的回归方程。运用方差分析可知,该方程极显著(а=0.005),并且拟合较好。试验结果表明,出料压力对处理效率影响极显著,螺旋转速和螺距对处理效率影响较小。

大型汽轮机动静碰磨故障的诊断和处理综述

在高速旋转机械的运行中 ,动静件碰磨是最常见的故障之一。碰磨发生时 ,轻者使得机组出现强烈振动 ,严重的甚至可以造成整个轴系毁坏。因此 ,在介绍汽轮机动静碰磨的机理和振动信号特征的基础上 ,归纳总结引起该类故障的主要因素 。