Morphology and corrosion resistance of composite coatings obtained by phosphating and molybdate post-sealing on galvanized steel

The phosphated hot-dip galvanized(HDG) sheets were post-sealed with sodium molybdate solution to improve the corrosion resistance of phosphate coatings. The morphology,chemical composition and corrosion resistance of the coatings were investigated using scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),Tafel polarization measurements and neutral salt spray(NSS) tests,and were compared with those of the single coatings. The results show that post-sealing the phosphated HDG steel with molybdate solution,the pores among the zinc phosphate crystals are sealed with molybdate films containing Zn,P,O and Mo,and the continuous composite coatings are formed. The suppression of both the anodic and the cathodic processes of zinc corrosion on the samples are enhanced significantly. The synergistic corrosion protection effect of the single phosphate coatings and molybdate films for zinc is evident. The corrosion resistance of the composite coatings increases with phosphating time up to 300 s.

In vitro corrosion and biocompatibility of phosphating modified WE43 magnesium alloy

Phospahting coated WE43 magnesium alloy was prepared by an immersion method. The microstructure, corrosion resistance and biocompatibility of the coated alloy were investigated. Scanning electron microscopy （SEM） and X-ray diffraction （XRD） were used to examine the microstructure and the composition of the coated alloy. The corrosion resistance was studied by means of potentiodynamic polarization method and the biocompatibility of the surface modified WE43 alloy was evaluated by （3-（4,5）-Dimethylthiazol-2, yl）-2,5-diphenyltetrazolium bromide （MTT） and hemolysis test. The results show that the phosphating coating can enhance the corrosion resistance of WE43 alloy and can be a good candidate to increase the biocompatibility of WE43 alloy.

Self-healing mechanism of composite coatings obtained by phosphating and silicate sol post-sealing

Silicate sol post-treatment was applied to form a complete composite coating on the phosphated zinc layer. The chemical compositions of the coatings were investigated using XPS. The coated samples were firstly scratched and then exposed to the neutral salt spray(NSS) chamber for different time. The microstructure and chemical compositions of the scratches were studied using SEM and EDS. And the non-scratched coated samples were compared. The self-healing mechanism of the composite coatings was discussed. The results show that during corrosion, the self-healing ions in composite coatings dissolve, diffuse and transfer to the scratches or the defects, and then recombine with Zn2+ to form insoluble compound, which deposits and covers the exposed zinc. The corrosion products on the scratches contain silicon, phosphorous, oxygen, chloride and zinc, and they are compact, fine, needle and flake, effectively inhibiting the corrosion formation and expansion of the exposed zinc layer. The composite coatings have good self-healing ability.

Effects of Hydroxylamine Sulfate and Sodium Nitrite on Microstructure and Friction Behavior of Zinc Phosphating Coating on High Carbon Steel

Hydroxylamine sulfate （HAS） and sodium nitrite are used as the accelerators for zinc phos- phate coating on high carbon steel. Phase evolution of phosphate coating was investigated by X-ray diffraction. It is found that the phosphating coatings are mainly composed of hopeite Zn3Fe（PO4）2.4H2O and phosphophyllite Zn2Fe（PO4）2.4H2O. The microstructural changes of the phosphate coating, as a function of phosphating time, were evaluated by scanning elec- tron microscopy. Four-ball friction experiments reveal that hydroxylamine sulfate instead of sodium nitrite can effectively reduce the friction coefficient of lubricated phosphating coat- ing. Therefore, it may be expected that HAS will be widely used as a fast and ECO-friendly accelerator in phosphate industry.

Pr,Yb,Ho:GdScO_(3)晶体生长及光谱性能

2.7-3.0μm波段激光在很多领域具有重要应用,为探索和发展该波段新型晶体材料,本文采用提拉法生长出Pr,Yb,Ho:GdScO_(3)晶体,通过共掺入Pr3+离子以达到衰减Ho^(3+):^(5)I_(7)能级寿命的目的.采用X射线衍射测试得到了晶体的粉末衍射数据,测量了拉曼光谱,并对晶体的拉曼振动峰进行指认,对Pr,Yb,Ho:GdScO_(3)晶体的透过光谱、发射光谱和荧光寿命进行表征.Yb^(3+)的最强吸收峰在966 nm,吸收峰半峰宽为90 nm;2.7-3.0μm波段最强发射峰在2850 nm,半峰宽为70 nm;Ho^(3+):^(5)I_(6)和^(5)I_(7)能级寿命分别为1094μs和56μs.与Yb,Ho:GdScO_(3)晶体相比,Yb^(3+)的吸收峰和2.7-3.0μm的发射峰半峰宽明显展宽,同时下能级寿命显著减小,计算表明Ho^(3+):^(5)I_(7)与Pr^(3+):^(3)F_(2)+^(3)H_(6)能级之间能实现高效的能量传递.以上结果表明Pr,Yb,Ho:GdScO_(3)晶体是性能更优异的2.7-3.0μm波段激光材料.

水平定向结晶法生长浓度渐变Yb∶YAG激光晶体及光谱性能研究

本文采用水平定向结晶(HDC)法成功生长出180 mm×81 mm×16 mm的浓度渐变Yb∶YAG激光晶体,从放肩部位和尾部分别获取了尺寸为40 mm×40 mm×7 mm、70 mm×70 mm×7 mm的Yb∶YAG激光晶体板条各两件。采用632 nm激光、偏光应力仪对晶体板条的光学性质进行检测,实验结果发现靠近晶坯自由表面的板条内部通透,无散射光路,应力较小且分布均匀,表明该晶体板条具有优异的光学质量。进一步测试分析了晶体板条不同位置处的吸收光谱,根据935 nm波长处的吸收系数计算出Yb^(3+)的掺杂浓度,发现40 mm×40 mm×7 mm的激光晶体板条中Yb^(3+)掺杂浓度沿晶体生长方向逐步增加,浓度梯度约为0.42%/cm;而70 mm×70 mm×7 mm的激光晶体板条中Yb^(3+)掺杂浓度几乎保持不变,约为4.50%。

Yb∶CaF_(2)透明陶瓷的压力辅助烧结及其性能研究

本文采用化学共沉淀法合成了5%(原子数分数,下同)Yb∶CaF_(2)纳米粉体。经过冷冻干燥后,粉体的团聚程度有所减轻,粉体呈立方片层状,平均颗粒尺寸约为40 nm。以冷冻干燥后的粉体为原料,通过热压烧结结合热等静压(HIP)烧结后处理制备了高光学质量的5%Yb∶CaF_(2)透明陶瓷。分析了热压烧结过程中样品的致密化行为,并对陶瓷的显微结构、直线透过率、吸收光谱及激光性能进行测试与表征。结果表明,陶瓷坯体在热压烧结时的保温阶段存在致密化驱动力的激活阈值,同时HIP后处理能够进一步压缩和排除热压陶瓷内残留气孔,有效提高陶瓷的光学质量。通过热压烧结(625℃×2 h,50 MPa)结合HIP后处理(600℃×3 h,100 MPa Ar)制备的5%Yb∶CaF_(2)透明陶瓷在400和1200 nm处的直线透过率分别为72.6%和92.2%(厚度2 mm),其在976 nm处的吸收截面为0.52×10^(-20)cm^(2)。使用波长为930 nm的光纤耦合二极管激光器(LD)端面泵浦Yb∶CaF_(2)透明陶瓷,获得了最大输出功率为0.81 W、斜率效率为9.7%的准连续激光输出。

谷子SiNF-YB亚家族基因的单倍型与功能分析

谷子属于短日照植物,是我国北方重要的杂粮作物,随着对谷子的深入研究,越来越多与逆境相关的转录因子被发现,其中NF-Y家族便是一类可以与启动子中CCAAT-box相结合的转录因子,包括3个亚家族NF-YA、NF-YB、NF-YC。本研究针对谷子SiNF-YB亚家族的14个基因进行研究,通过亚细胞定位分析,发现该亚家族中除了SiNF-YB8和SiNF-YB15其余成员主要定位于细胞核中。顺式作用元件分析显示,在各成员启动子区域包含大量与非生物胁迫响应以及光周期相关的顺式作用元件。单倍型分析显示,SiNF-YB4是一个与耐旱有很强相关性的基因,有3种单倍型,其中H003是优异的抗旱单倍型;SiNF-YB12是一个与抽穗有很强相关性的基因,有H001和H002两种单倍型。转录组数据分析显示,抗旱和敏旱品种干旱处理前后,SiNF-YB5在根部的表达量存在显著性差异;在长日照与短日照条件下,SiNF-YB4在春谷和夏谷中的表达量存在显著差异。本研究结果为后续进一步探究谷子SiNF-YB亚家族基因的功能提供了重要的理论依据,同时为培育抽穗期与环境相适应的谷子抗旱品种奠定基础。

980-nm all-fiber mode-locked Yb-doped phosphate fiber oscillator based on semiconductor saturable absorber mirror and its amplifier

A 980-nm semiconductor saturable absorber mirror（SESAM） mode-locked Yb-doped phosphate fiber laser is demonstrated by using an all-fiber linear cavity configuration. Two different kinds of cavity lengths are introduced into the oscillator to obtain a robust and stable mode-locked seed source. When the cavity length is chosen to be 6 m, the oscillator generates an average output power of 3.5 m W and a pulse width of 76.27 ps with a repetition rate of 17.08 MHz. As the cavity length is optimized to short, 4.4-m W maximum output power and 61.15-ps pulse width are produced at a repetition rate of 20.96 MHz. The output spectrum is centered at 980 nm with a narrow spectral bandwidth of 0.13 nm. In the experiment, no undesired amplified spontaneous emission（ASE） nor harmful oscillation around 1030 nm is observed. Moreover,through a two-stage all-fiber-integrated amplifier, an output power of 740 m W is generated with a pulse width of 200 ps.

Synergistic Corrosion Inhibition Effect of Molybdate and Phosphate Ions for Anodic Oxidation Film Formed on 2024 Aluminum Alloy

In order to effectively improve the corrosion resistance of aluminum alloys, anodic oxidation technique was used to generate the oxide film. We investigated the influences of two inorganic corrosion inhibitors(ammonium dihydrogen phosphate and sodium molybdate) on the corrosion resistance of anodic oxidation films on 2024 aluminum alloy, and studied the synergistic effect of two corrosion inhibitors. The corrosion resistance of anodic oxidation film in 3.5 wt% NaCl solution was evaluated by electrochemical impedance spectroscopy(EIS) and potentiodynamic polarization curves. Results show that, after adding the single ammonium dihydrogen phosphate or sodium molybdate of 0.01 M to oxalic acid electrolyte, inhibition efficiencies of the anodized samples are 10% and 47%, respectively. However, in the presence of two inhibitors with the same concentration of 0.01 M, inhibition efficiency can be as high as 92%. Therefore, we observed the significantly synergistic corrosion inhibition effect of molybdate and phosphate ions for anodic oxidation film formed on 2024 aluminum alloy.

Composition and Performance of the Composite Coatings Obtained by Phosphating and Cerium Nitrate Post-Sealing on Galvanized Steel

To improve the corrosion resistance of phosphate coatings, the phosphated hot-dip galvanized (HDG) steel was post-sealed with cerium nitrate solution. The morphology, composition, corrosion resistance of the coatings was investigated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and neutral salt spray (NSS) tests. The results show that after post-sealing the phosphated HDG samples with cerium nitrate solution, the pores among the zinc phosphate crystals are sealed by the compounds containing phosphorus, oxygen and cerium; the zinc phosphate crystals are covered by the flocculent cerium compounds; and the continuous composite coatings are formed on HDG steel. The corrosion resistance of the composite coatings, which increases with the increase in phosphating time and cerium nitrate post-sealing time, is far higher than that of the single phosphate coatings. The composite coatings with the optimal corrosion resistance are obtained for phosphating 300 s and post-sealing 300 s; and the corrosion resistance is more outstanding than that of the chromate coatings.

Zinc phosphating of 6061-Al alloy using REN as additive

Zinc phosphate coating formed on 6061-A1 alloy was studied with the help of electrochemical measurements, Fourier Transform Infrared （FTIR）, and Scanning Electron Microscopy （SEM）, after dipping it in phosphating solutions containing different concentrations of Rare Earth Nitrate （REN）. REN, which acted as an accelerator in the phosphating solution, could catalyze the surface reaction and accelerate the phosphating process. REN mainly enabled the P in the phosphate coating to exist in the form of PO4^3- and promoted the hydrolysis of phosphatic acid in a liquid layer at the cathodes. This resulted in the evolution of H2 at the cathodes, which increased the local pH value and in turn drove the precipitation of the phosphate coating. Additionally, REN was adsorbed on the surface of the aluminum substrates to form a gel during the phosphating process. These gel particles were good crystal seeds, which helped to form phosphate crystal nuclei and possess the function of a nucleation agent that could decrease the phosphate crystal size. The corrosion resistance of the formed zinc phosphate coatings was improved.

Self-healing Performance of Composite Coatings Prepared by Phosphating and Cerium Nitrate Post-sealing

The phosphated and cerium nitrate post-sealed galvanized steel was firstly scratched to expose zinc layer and then placed in neutral salt spray （NSS） chamber for different durations. The microstructure and compositions of the scratches were investigated using SEM and EDS. The phases of the corrosion products were examined through XRD. The self-healing mechanism of the composite coatings was discussed. The experimental results show that the composite coatings have an excellent corrosion resistance. The corrosion products increase with corrosion time and finally cover the whole scratch. They contain phosphorous, cerium, oxygen, chloride and zinc, and are fine needle and exceedingly compact. The composite coatings are favorable self-healing. During corrosion, the self-healing ions such as Ce3＋, Ce4＋, PO43-, Zn2＋ in the composite coatings were dissolved, migrated, recombined, and covered the exposed zinc, impeding zinc corrosion. The self-healing process of the scratches on the composite coatings can be divided into three stages, about 2 h, 4 h, and 24 h, respectively.

Spectral and Lasing Properties of Er^(3+0/Yb^(3+) Co-Doped Phosphate Glasses Pumped by LD

Er^3 ＋/Yb^3 ＋ phosphate glasses were fabricated. According to McCumber theory, the stimulated emission cross-section of Er^3＋ ions at 1533 nm was calculated on the basis of absorption spectrum, and 0.84 × 10^-20 cm^2 is derived, the fluorescence lifetime of ^4I13/2 level is 8.5 ms. An Er^3＋/Yb^3＋ co-doped phosphate glass CW laser pumped by LD was demonstrated at room temperature. The maximum output power is 80 mW and slope efficiency is 16.5%.

棒状结构NaGdF_(4):Yb^(3+),Er^(3+)上转换发光性能的研究

以乙二胺四乙酸二钠(EDTD-2Na)为螯合剂,采用水热法合成了棒状结构的NaGdF_(4):Yb^(3+),Er^(3+)纳米粉末。分别借助X射线衍射(XRD)、荧光光谱仪(PL)和扫描显微镜(SEM)对其晶体结构、发光强度和表面形貌进行分析和表征。探究了稀土前驱体、水热温度和水热时间的实验条件对NaGdF_(4):Yb^(3+),Er^(3+)纳米粉末上转换发光强度的影响;研究了氟源和钠源对NaGdF_(4):Yb^(3+),Er^(3+)晶体形貌和上转换发光强度的改善;同时,采用煅烧处理的方法,进一步探究样品的形貌和发光强度收到的影响。实验结果表明NH4F与NaOH作为氟源和钠源及200℃煅烧1 h得到的棒状结构NaGdF_(4):Yb^(3+),Er^(3+)的发光强度最好,色坐标(CIE)绿色发光强度从84%提升到94.88%。

Study on phosphating treatment of aluminum alloy:role of yttrium oxide

Zinc phosphate coatings formed on 6061-Al alloy, after dipping in phosphating solutions containing different amounts of Y2O3（yttrium oxide）, were studied by scanning electron microscopy （SEM）, X-ray diffraction （XRD） and electrochemical measurements. Significant variations in the morphology and corrosion resistance afforded by zinc phosphate coating were especially observed as Y2O3 in phosphating solution varied from 0 to 40 mg/L. The addition of Y2O3 changed the initial potential of the interface between aluminum alloy substrate and phosphating solution and increased the number of nucleation sites. The phosphate coating thereby was less porous structure and covered the surface of aluminum alloy completely within short phosphating time. Phosphate coating was mainly composed of Zn3（PO4）2·4H2O （hopeite） and AlPO4（aluminum phosphate）. Y2O3, as an additive of phosphatization, accelerated precipitation and refined the gain size of phosphate coating. The corrosion resistance of zinc phosphate coating in 3% NaCl solution was improved as shown by polarization measurement. In the present research, the optimal amount of Y2O3 was 10-20 mg/L, and the optimal phosphating time was 600 s.

欧洲葡萄NF-YB3基因克隆与表达分析

为探究VvNF-YB3基因在葡萄生长发育和响应非生物胁迫过程中的功能,以无核白为试材,克隆得到了VvNF-YB3基因编码区序列,全长为624 bp,编码207个氨基酸,蛋白质等电点6.31,不稳定指数27.66,总平均疏水指数-0.738,为一酸性、稳定的亲水蛋白。通过生物信息学分析发现,VvNF-YB3基因位于10号染色体,含有1个内含子,编码蛋白质存在1个CBFD_NFYB_HMF结构域,与河岸葡萄NF-YB3相似性最高。VvNF-YB3的二级结构中α-螺旋和无规则卷曲占比较高,三级结构为单体的螺旋-卷曲-螺旋,启动子中包含响应激素和胁迫的多个顺式作用元件。VvNF-YB3基因在葡萄的叶片、卷须、花、幼果和茎中均表达,且在成熟的叶片中表达量最高。PEG模拟的干旱、低温和高温胁迫均可影响VvNF-YB3基因的表达,VvNF-YB3为一胁迫响应基因。VvNF-YB3的互作蛋白大多是核因子Y家族的亚基,ERF、bHLH、ARF等27个转录因子可能调控VvNF-YB3基因的表达。由此推测,VvNF-YB3基因可能通过受到上游转录因子的调控并与其他NF-Y蛋白互作响应各种环境胁迫。

Hydrothermal Synthesis and Structure of a New Molybdenum Phosphate: (NH_3CH_2CH_2NH_3)_(2.5)[Mo_5O_(15)(PO_4) (HPO_4)]·7.5H_2O

The title compound (C5N5H41P2Mo5O30.5) was synthesized under hydrothermal condition and its crystal structure was determined by X-ray diffraction. It belongs to triclinic system, space group P , with a=9.9645(6), b=10.8666(7), c=15.814(1)? α=71.482(3), β=88.528(2), γ=78.448(2)°, V=1589.4(2)3, Dc=2.510g/cm3, Z=2,μ=2.138mm-1,λ(MoKα) = 0.71073 ? F(000)=1180. The final R and wR were 0.0396 and 0.1052 for 6626 observed reflections with I ≥2σ(I), respectively. The result of the structure analysis indicates that the [Mo5O15(PO4) (HPO4)]5- anion in the title compound consists of five edge-sharing or corner-sharing MoO6 octahedra and two corner-sharing PO4 tetrahedra. Each MoO6 octahedron adopts distorted octahedral geometry.

THE IMMUNOHISTOCHEMISTRY AND IN SITU cDNA-mRNA HYBRIDIZATION OF CARBAMYL PHOSPHATE SYNTHETASE I IN ENZYME-ALTERED LIVER CELLS DURING CARCINOGENESIS

The changes of carbamyl phosphate synthetase I(CPS 1)in diethylnitrosamine-(DEN)-inducedenzyme-altered liver cells were studied by means of immunohistochemical(PAP)and in situcDNA-mRNA hybridization methods.The experimental rats were treated with DEN,2-acetylaminofluorene(2-AAF)and 2/3 hepatectomy according to Solt-Farber’s protocol andwere further promoted by oral daily administration of 0.05% phenobarbital in drinking water.The results showed that the average number of lesions showing abnormal expression of CPS1 was relatively constant over the course of the experiment(8 months),while the numberof normally expressing lesions gradually decreased.The former lesions were also largerin volume than the latter ones.We conclude that in DEN-initiated lesions the abnormallyexpressed CPS 1 lesions may grow continuously,thus leading to the formation of largernodules.We also suspect that some of these lesions have increased tendencies to developinto tumors.

Phosphonate-derived nitrogen-doped cobalt phosphate/carbon nanotube hybrids as highly active oxygen reduction reaction electrocatalysts

The exploration of cost-effective non-noble-metal electrocatalysts is highly imperative to replace the state-of-the-art platinum-based catalysts for oxygen reduction reaction(ORR). Here, we prepared cobalt phosphonate-derived N-doped cobalt phosphate/carbon nanotube hybrids(Co Pi C-N/CNTs) by hydrothermal treatment of N-containing cobalt phosphonate and oxidized carbon nanotubes(o-CNT) followed by high-temperature calcination under nitrogen atmosphere. The resultant Co Pi C-N/CNT exhibits a superior electrocatalytic performance for the ORR in alkaline media, which is equal to the commercial Pt/C catalyst in the aspect of half-wave potential, onset potential and diffuse limiting current density. Furthermore, the excellent tolerance to methanol and strong durability outperform those of commercial Pt/C. It is found that cobalt phosphonate-derived N-doped cobalt phosphate and the in-situ formed graphitic carbons play key roles on the activity enhancement. Besides, introducing a suitable amount of CNTs enhances the electronic conductivity and further contributes to the improved ORR performance.