不同工艺下镁合金MAO/GO/SA复合涂层的耐蚀性

为提高AZ91D镁合金基体的耐蚀性，采用微弧氧化、电沉积和自组装工艺在AZ91D镁合金表面制备了微弧氧化/氧化石墨烯/硬脂酸(MAO/GO/SA)复合涂层。通过SEM对复合涂层的微观组织结构进行了分析，利用电化学阻抗谱、极化曲线测试了复合涂层的耐蚀性能。结果表明，最佳电沉积电压为4 V,此时，MAO/GO复合涂层的电荷转移电阻(R_ct)为4.41×10⁵Ω·cm²,腐蚀电流密度(J_corr)为3.88×10^-7 A/cm²。醇水比为7∶3时，MAO/GO/SA复合涂层的R_ct值为3.07×10⁶Ω·cm²,J_corr为3.02×10^-8 A/cm²,达到超疏水状态，涂层耐蚀性最好。     

氧化甾醇抑制血管平滑肌细胞(VSMC)增殖及诱导其凋亡的作用1

目的: 研究 3β, 5α, 6β-胆甾烷三醇(Triol) 和25-羟胆固醇(25OH) 对 VSMC 增殖的影响, 探讨氧化甾醇在动脉粥样硬化(AS) 发病中的作用和意义。 方法: 培养和鉴定新西兰白兔主动脉 VSMC; 以含不同浓度的Triol 和 25OH 的培养液作用于VSMC 为实验组, 不含氧化甾醇或含胆固醇的培养液作为对照组。 VSMC 增殖及其代谢活性以 WST-1 测定, 细胞凋亡以光镜、透射电镜、脱氧核苷酸末端转移酶介导脱氧尿苷三磷酸缺口末端标记(TUNEL) 判断。结果: 在1×10^-9 ~ 1 ×10^-7mol^·L^-1 范围的 Triol 和 25OH 对VSMC 的 WST-1代谢活性无明显变化(P >0.05), 而≥1×10^-6mol^·L^-1 的氧化甾醇则使其代谢活性显著下降 (P <0.01); ≥20 ×10^-6 mol^·L^-1 的 Triol 和25OH 诱导VSMC 胞体皱缩变小、染色质在核周边浓集、核碎裂、 空泡和凋亡小体形成等超微结构变化; TUNEL 呈阳性反应。结论: 小剂量氧化甾醇无促进VSMC 增殖而较大剂量氧化甾醇可诱导 VSMC 凋亡。     

靶向内皮细胞α7受体的新化合物对鸡胚绒毛尿囊膜血管生成的影响

目的: 研究靶向内皮细胞α₇ 受体的新化合物对鸡胚绒毛尿囊膜(CAM)血管新生的影响。方法: 应用鸡胚绒毛尿囊膜模型,通过计数血管的分支点数,观察16种靶向内皮细胞α₇受体的新化合物对于在体血管新生的影响。结果与结论: 化合物13、14在1~100μmol·L^-1浓度范围内,既没有促进血管新生的作用,也没有抑制血管新生的作用,与生理盐水组相比无显著差异,而在浓度为1000μmol·L^-1时,对CAM的血管新生有促进作用。化合物5在浓度为100和1000μmol·L^-1有抑制血管新生的作用,而在浓度为1和10μmol·L^-1时,则对血管新生没有影响。     

阿芬太尼对再灌注心肌功能的保护作用及其机制

目的: 研究阿芬太尼对缺血再灌注心肌功能的保护作用及其作用机制。方法: 采用 Langendorff离体大鼠心脏模型, 以停灌的方式造成全心缺血25 min, 然后复灌 30 min, 药物于缺血前 10 min给予并持续到复灌末。观察 50 μg·L^-1 和 100 μg·L^-1阿芬太尼及其与纳洛酮和 L-NAME 合用时对缺血前及再灌注期间左心功能的影响, 并测定再灌注末时心肌组织 ATP 和 NOS 的含量。 结果: (1) 在非缺血情况下, 100 μg·L^-1阿芬太尼能使 HR 减慢, 对LVEDP、LVDP、±dp/dt_max 和 CF 无明显影响;(2)50 μg·L^-1 和 100 μg·L^-1 阿芬太尼均能明显促进再灌期间左心功能和冠脉流量的恢复, 且 100 μg·L^-1阿芬太尼比 50 μg·L^-1 阿芬太尼作用更明显;(3)200 μg·L^-1 纳洛酮和 100 μmol·L^-1 L-NAME 均削弱了阿芬太尼对缺血再灌注心肌功能恢复的有利作用。结论: 阿芬太尼对离体大鼠的心肌功能影响轻微且能促进缺血再灌注后心肌功能的恢复, 其作用机制可能与阿片受体和内皮细胞释放的一氧化氮有关。     

甲氨蝶呤治疗异位妊娠疗效及失败因素的评价

目的 探讨甲氨蝶呤单次肌肉注射治疗异位妊娠的疗效, 并分析其治疗失败的相关因素。 方法 对比分析成功组及失败组的临床资料, 包括停经天数、治疗前β-HCG 值、包块直径、腹痛情况、治疗3 d后β-HCG 值下降率及包块直径改变情况。 结果 成功组停经天数平均为53 ±5 d, β-HCG 值平均为1483 ±216 IU·L^-1, 包块直径平均为2.9 ±0.9 cm;失败组停经天数平均为62 ±6 d, β-HCG 值平均为6661 ±126 IU·L^-1, 包块直径平均为4.1 ±0.6 cm。成功组有14.3 %的病人停经天数≥60 d, 11.4 %的病人血β-HCG 值≥4 000 IU·L^-1, 治疗3 d 后β-HCG 值下降率≤15 %的为14.3 %, 包块直径增加≥25 %的为7.9 %;而失败组各数值分别为40.0 %、80.0 %、60.0 %、40.0 %。 结论 甲氨蝶呤是一种有效的治疗早期异位妊娠的药物;治疗前的β-HCG值、治疗3 d 后β-HCG 值下降率及包块直径改变情况与治疗失败关系极大;胎心搏动并非为异位妊娠药物治疗的禁忌证。     

RP-HPLC法测定人血浆中奥美拉唑浓度及其在健康男性志愿者药代动力学研究

目的: 建立人血浆中奥美拉唑的含量测定方法, 用于其血药浓度测定并进行临床药代动力学研究。方法: 1 ml 血浆样品以二氯甲烷提取, 采用反相高效液相-二极管阵列检测器分离测定血浆中的奥美拉唑浓度。色谱条件:krumasil C18 柱(4.6 mm ×200 mm, 5 μm), 流动相为乙睛:三蒸水(含0.01mol·L^-1磷酸氢二钠, 三乙胺调pH 7.5) =45:55(v/v);流速:1.3 ml·min^-1, 检测波长302 nm, 进样量30μl。9 例健康志愿者单剂量口服40 mg 奥美拉唑肠溶胶囊, 用高效液相色谱法测定给药后不同时间点血浆中奥美拉唑的浓度, 计算其药动学参数。结果: 奥美拉唑在10 ~ 2 000 μg·L^-1浓度范围内呈良好的线性关系, 最低检测浓度为10 μg·L^-1。高、中、低浓度的方法回收率分别为92.35%、96.90%、100.04%, RSD 均小于15%。健康人体药动学研究证明, 奥美拉唑的药-时曲线符合一室模型。结论: 本方法灵敏度高、专属性强、准确、简便, 适用于奥美拉唑的人体药代动力学研究。     

西洛他唑的高效液相色谱法测定及药动学研究

目的 建立测定人血浆中西洛他唑含量的高效液相色谱(HPLC) 法, 并研究西洛他唑片在健康人体内的药动学。 方法 色谱柱为Hypersil C18 柱(4.6 mm ×200 mm, 5 μm), 流动相为乙腈-水(45∶55), 流速1.0 ml·min^-1, 柱温30 ℃, 检测波长254 nm, 西洛他唑血浆样品以2 mol·L^-1NaOH-无水乙醚(1∶4) 提取, 以地西泮为内标。 结果 标准曲线线性范围20 ~ 2 000 μg·L^-1 (r=0.9999)。血浆中西洛他唑最低检测限为10 μg·L^-1。平均提取回收率为80.2 % ±3.6 %, 平均方法回收率为97.0 % ±3.8 %, 日内RSD ≤5.8 %, 日间RSD ≤10.1 %。应用该法研究了10 例健康志愿者口服100 mg 西洛他唑后的药动学;其体内过程符合二室模型, t_max 为3.58±1.08 h, C_max 为920 ±230 μg·L^-1, AUC_0-48 为11.0±3.3 mg·h^-1·L^-1。 结论 此法简便、快速, 适用于药物分析, 其药动学数据可为临床合理用药、新药研制及剂型改进提供理论依据。     

萘哌地尔胶囊和片剂在中国健康男性志愿受试者的生物等效性比较

目的: 以萘哌地尔片剂为对照, 研究萘哌地尔胶囊的人体药动学过程和生物等效性。方法: 18 名健康成年男性志愿者采用随机分组自身交叉对照试验设计方法, 采用HPLC-荧光检测, 血样最低定量限为1 μg ·L^-1, 平均绝对回收率85.2 %~ 89.9 %, 日内、日间变异系数(RSD) 小于8.05 %。血浆标准曲线在1.56 ~ 400 μg·L^-1 范围内相关性良好, r =1 。结果: 萘哌地尔胶囊和片剂的主要药动学参数为:T_max:0.63±0.24 和0.57±0.21 h ;C_max:129.1±60.7和138.3±72.5 μg·L^-1 ;T1 2:5.9±1.7 和6.4±2.1 h ;AUC_0-24:295.6±90.9 和291.6±89.3 μg·L^-1 ·h-1 ;AUC_0-∞:320±97.2 和318.0±98.3 μg·L^-1 ·h^-1 。萘哌地尔胶囊的相对生物利用度F_0-24 、F_0-∞分别为101.9 %±12.9 %和101.2 %±12.3 %。结论: 两种制剂生物等效。     

盐酸伊伐布雷定片人体药动学研究

目的: 研究盐酸伊伐布雷定片在中国健康志愿者中的单次及连续多次给药药动学特征。方法: 12例受试者采用随机开放二重3×3拉丁方试验设计,研究单次及连续多次给药药动学特征;采用LC-MS/MS法测定血浆中伊伐布雷定及其活性代谢产物S-18982的药物浓度。药动学参数采用WinNonlin软件计算。结果: 单次(5、10、15 mg)给药后伊伐布雷定的主要药动学参数:C_max分别为(19±10)、(47±24)、(79±41) μg/L,t_max分别为(0.7±0.5)、(0.6±0.3)、(0.5±0.1) h; AUC_last分别为(58±32)、(138±83)、(189±115) μg·h·L^-1;AUC_inf分别为(59±32)、(140±84)、 (191±116) μg·h·L^-1;其活性代谢产物S-18982的主要药动学参数:C_max分别为(3.1±1.2)、(7.9±2.8)、(15.0±5.4) μg/L; t_max分别为(1.1±0.8),(0.8±0.4),(0.6±0.1) h;AUC_last分别为(17±8)、 (47±19)、 (76±29) μg·h·L^-1;AUC_inf分别为(20±8)、(52±21), (85±30) μg·h·L^-1。连续多次给药 5 mg 后伊伐布雷定的主要药动学参数:C_max(20±7) μg/L;t_max(1.0±0.7) h; AUC_last( 67±32) μg·h·L^-1; AUC_inf (69±33) μg·h·L^-1;其活性代谢产物S-18982的主要药动学参数:C_max(4.5±1.3) μg/L;t_max(1.1±0.8) h; AUC_last (34±11) μg·h·L^-1; AUC_inf (39±13) μg·h·L^-1。结论: 单次5~15 mg 给药后,伊伐布雷定的体内过程符合一级线性动力学过程,代谢产物S-18982的体内过程呈非线性;连续多次 5 mg 给药后,母药和代谢产物的血药浓度第5天可达稳态,母药在体内无蓄积,代谢产物存在蓄积现象。     

马来酸氯苯那敏片健康人体药动学和相对生物利用度

目的: 研究马来酸氯苯那敏片剂在健康人体内的相对生物利用度。方法: 采用HPLC 法测定18名男性健康志愿者单剂量交叉口服马来酸氯苯那敏片参比制剂和被试制剂8 mg 后不同时间血浆药物浓度。用3P97 药动学软件进行药动学参数计算及生物等效性评价。结果: 参比和被试制剂的药-时曲线均符合一房室模型,两制剂的主要药动学参数如下:C_max 分别为(15.74±7.06)μg·L^-1 和(14.88±4.40)μg·L^-1;t_max 分别为(3.9±1.2) h 和(4.5±0.8) h;t_1/2ke 分别为(15.54±3.76) h 和(14.49±3.24) h;AUC_0-t 分别为(248.86±78.52)μg·h·L^-1和(245.09±90.77)μg·h·L^-1,AUC_0-∞分别为(292.64±99.21)μg·h·L^-1 和(282.04±98.64)μg·h·L^-1 。与标准参比制剂相比,被试制剂的相对生物利用度F_0-t为(1 04.1±36.1) %,F_0-∞为(103.2±35.6) %。结论: 方差分析与双单侧t 检验证明,两种制剂具有生物等效性。     

装载缓蚀剂的蒙脱土对环氧涂层耐蚀性能的研究

将不同比例的装载缓蚀剂蒙脱土和环氧树脂混合制备出纳米复合环氧涂层。根据电化学阻抗谱 (EIS) 和盐雾实验对涂层的耐蚀性进行表征。结果表明,3%装载蒙脱土环氧涂层的水扩散系数为9.89×10^-11 cm²/s,孔隙率为2.22×10^-8,整个浸泡过程中阻抗值在10⁹ Ωcm²以上,表现出最佳的耐蚀性。     

Effect of silicate pretreatment, post-sealing and additives on corrosion resistance of phosphated galvanized steel

Sodium silicate （water glass） pretreatment before phosphating, silicate post-sealing after phosphating and adding silicate to a traditional phosphating solution were respectively carried out to obtain the improved phosphate coatings with high corrosion resistance and coverage on hot-dip galvanized（HDG） steel. The corrosion resistance, morphology and chemical composition of the coatings were investigated using neutral salt spray（NSS） tests, scanning electron microscopy（SEM） and energy dispersive spectroscopy（EDS）. The results show that pretreatment HDG steel with silicate solutions, phosphate coatings with finer crystals and higher coverage are formed and the corrosion resistance is enhanced. Adding silicate to a traditional phosphating solution, the surface morphology of the coatings is nearly unchanged. The corrosion resistance of the coatings is mainly dependent on phosphating time. Phosphating for a longer time （such as 5 min）, the corrosion resistance, increasing with concentration of silicate, is improved significantly. Post-sealing the phosphated HDG steel with silicate solutions, the pores among the zinc phosphate crystals are sealed with the films containing Si, P, O and Zn and the continuous composite coatings are formed. The corrosion resistance of the composite coatings, related to the pH value, contents of hydrated gel of silica and Si2O^2- 5 and post-sealing time, is increased markedly. The improved coatings with optimal corrosion resistance are obtained for phosphating 5 min and post-sealing with 5 g/L silicate solution for 10 min.     

Corrosion protection of NdFeB magnets by phosphating with tungstate incorporation

In this investigation the effect of surface treatments on the corrosion resistance of a commercial NdFeB sintered magnet has been investigated. A solution of 10 g L^− 1 NaH₂PO₄, acidified to pH 3.8 has been used for phosphating this magnet. The corrosion resistance of the phosphated magnet was investigated in a 0.10 mol L^− 1 Na₂SO₄ solution by electrochemical impedance spectroscopy and cyclic voltammetry with rotating disc electrode. The obtained results reveal that the resistance decreases with exposure time due to the development of pores and/or defects in the conversion coating exposing the substrate to corrosive attack. The effect of tungstate incorporation into the phosphate conversion coating resulting from a phosphating treatment prior to immersion in the tungstate solution was evaluated. The proposed treatment consists of re-immersing the phosphated samples in a 0.1 mol L^− 1 Na₂WO₄ solution during 72 h at the open circuit potential (OCP). Under these conditions, the corrosion resistance of the magnet was improved and this was attributed to the formation of a protective layer due to the adsorption of tungstate anions at the metallic substrate exposed in the coating, decreasing metal dissolution.     

海洋环境中芽孢杆菌对聚氨酯清漆涂层分解的影响

采用电化学技术、扫描电镜和红外光谱等多种方法研究了海洋环境中芽孢杆菌对聚氨酯清漆涂层分解作用以及对腐蚀行为的影响.结果 表明,在浸泡时间为1h时,芽孢杆菌并没有对聚氨酯清漆涂层产生明显的降解作用.随着浸泡时间的延长,在含有芽孢杆菌的海水中的涂层耐蚀性明显小于在无菌海水中涂层的耐蚀性,表明芽孢杆菌能导致涂层的降解.浸泡初...     

Microstructural characterization and surface properties of zinc phosphated medium carbon low alloy steel

The present study concerns an in-depth investigation of the influence of process parameters on zinc phosphating of medium carbon steel to have an understanding of nucleation and growth mechanism and the microstructures developed thereafter. Furthermore, the wear and corrosion behavior of phosphated steel were evaluated in details. Phosphating was carried out in zinc phosphate bath (6–8% ZnPO₄) using 0.43 wt.% Fe as catalyst at 90 °C with variable time ranging from 60 s to 1800 s followed by water rinsing and oil sealing. The microstructural evolution with time was recorded to understand the nucleation and growth phenomena. The morphology of coating was both plate and needle shaped. The microhardness of the coated layer is significantly lower than that of as-received steel. Fretting wear behavior against hardened steel ball showed that phosphating reduced the wear resistance which was possibly attributed to the presence of phosphate needles causing an increased coefficient of friction and the reduced hardness of the phosphate layer. Corrosion potential of the phosphated steel shifted towards noble direction as compared to the as-received one. The study of the corrosion rate also shows that the rate is considerably reduced by phosphating. Pitting corrosion resistance was also found to be increased (in terms of increased critical potential for pit formation) due to phosphating as compared to as-received steel.     

A Nickel-Manganese-Modified Low Zinc Phosphate Solution for Cathode-Electrophoretic Painting of Steel Substrates

PHOSPHATING TREATMENTS for the automobileindustry determine the paint adhesion and influence thecorrosion resistance of the automobile body.However,the traditionally used,so-called normal zinc processescan't satisfy with the requirement of cathode-electroph-oretic painting processes for their low alkalineresistance.In addition,the requirement for corrosionproofing has been heightened remarkably.Then thetraditionally normal zinc processes have,in severalcases,been replaced by use of low…     

The EIS investigation of powder polyester coatings on phosphated low carbon steel: The effect of NaNO2 in the phosphating bath

The effect of different type of iron-phosphate coatings on corrosion stability and adhesion characteristic of top powder polyester coating on steel was investigated. Iron-phosphate coatings were deposited on steel in the novel phosphating bath with or without NaNO₂ as an accelerator. The corrosion stability of the powder polyester coating was evaluated by electrochemical impedance spectroscopy (EIS), adhesion by pull-off and NMP test, while surface morphology of phosphate coatings were investigated by atomic force microscopy (AFM).The adhesion and corrosion stability of powder polyester coatings were improved with pretreatment based on iron-phosphate coating deposited from NaNO₂-free bath.     

偏钒酸铵对AZ91D镁合金表面磷酸盐转化膜的耐腐蚀性能影响的研究

为了提高镁合金磷化盐转化膜的耐腐蚀性能,向镁合金磷酸处理液中添加NH₄VO₃,采用中性盐雾实验、Tafel曲线和电化学阻抗测试、扫描电镜 (SEM) 测试和能量色散谱仪分析等方法检测膜层的性能,研究了NH₄VO₃对镁合金表面磷酸盐转化膜耐蚀性的影响。结果表明：加入NH₄VO₃后,镁合金化学转化膜表面的裂纹有细化和孔洞有减少的趋势;化学转化膜呈现明显的容抗特性,电化学阻抗可达273.6 Ω;自腐蚀电位正移了121.6 mV,自腐蚀电流密度明显减小,降低了接近一个数量级,耐腐蚀性能得到了很大的提升,表面化学转化膜的耐中性盐雾腐蚀时间大幅度增加,达到41 h。     

Effect of Sn ion implantation on electrochemical behavior of zircaloy-4

In order to study the effect of tin ion implantation on the aqueous corrosion behavior of zircaloy-4, specimens were implanted by tin ions with a dose range from 1×10¹⁶ to 5×10¹⁷ ions/cm² at an extracted voltage of 40 kV. The valence and element penetration distribution of the surface layer were analyzed by X-ray photoelectron spectroscopy (XPS) and auger electron spectroscopy (AES), respectively. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to examine the micro-morphology and microstructure of tin-implanted samples. When the dose is 5×10¹⁶ ions/cm² or higher, a large number of small tin balls are produced in the implanted surface. The potentiodynamic polarization measurement was employed to evaluate the aqueous corrosion resistance of zircaloy-4 in a 0.5 M H₂SO₄ solution. It was found that a significant improvement was achieved in the aqueous corrosion behavior of zircaloy-4 implanted with tin when the dose is 1×10¹⁶ ions/cm². When the dose is higher than 1×10¹⁶ ions/cm², the corrosion resistance of zircaloy-4 implanted with tin ions decreased compared with that of the as-received zircaloy-4. Finally, the mechanism of the corrosion behavior of the tin-implanted zircaloy-4 is discussed.     

Al含量对TiAlN涂层结构及性能的影响

目的 系统研究Al含量对TiAlN涂层结构以及硬度、热稳定性、抗氧化性能和耐腐蚀性能的影响.方法 利用阴极弧蒸发技术,采用Ti、Ti50Al50、Ti40Al60和Ti33Al67靶材制备出4种Ti1–xAlxN涂层.分别利用能量色散X射线光谱仪(EDX)、X射线衍射仪(XRD)、扫描电镜(SEM)、纳米压痕仪、热重分...