甲氨蝶呤对炎性细胞因子及丝裂原活化蛋白激酶信号通路的影响

目的: 探讨甲氨蝶呤(methotrexate,MTX)对类风湿关节炎(RA)发病起重要作用的炎性细胞因子IL-1β和TNF-α的作用及其可能的机制。方法: 用II型胶原建立类风湿关节炎(CIA)动物模型,以MTX(0.2 mg/kg/W)进行处理,6周后处死大鼠,取血清进行IL-1β和TNF-α检测;分离大鼠膝关节取关节滑膜细胞(FLS)进行培养、鉴定,检测脂多糖(LPS)诱导的FLS培养上清中IL-1β和TNF-α的含量,并观察MTX对FLS分泌IL-1β和TNF-α的影响;在FLS的培养中加入不同剂量的MTX,用Westen Blot方法检测FLS中ERK蛋白及磷酸化蛋白的表达。结果: 关节炎指数评分、关节肿胀度测定及关节病理显示造模成功,分离关节滑膜细胞经流式细胞仪检测FLS的血管细胞黏附分子-1(VCAM-1)的表达为 85.5%。造模后,CIA大鼠血清IL-1β和TNF-α明显增加,与空白对照组比较有统计学差异(P<0.05),MTX能有效减少CIA大鼠血清中IL-1β和TNF-α的含量(P<0.05),但未能恢复至正常水平。MTX能抑制LPS诱导的CIA大鼠关节FLS分泌IL-1β和TNF-α。Western Blot检测显示,不同浓度的MTX对CIA大鼠FLS中ERK蛋白的表达与模型对照组相比无统计学差异(P>0.05)。CIA大鼠 FLS中p-ERK蛋白的表达明显高于空白对照组(P<0.01),MTX干预后,低剂量组对p-ERK蛋白表达无明显影响,而中、高剂量组可降低p-ERK蛋白的表达(P<0.05)。结论: MTX既有免疫抑制作用,同时还通过抑制炎性细胞因子IL-1β和TNF-α而具有抗炎作用,其机制可能部分与其抑制MAPK信号通路中的ERK蛋白磷酸化有关。     

益气养阴生肌方对复发性口腔溃疡大鼠的治疗作用及其对黏膜炎症因子和机体免疫功能的影响

目的: 分析益气养阴生肌方对复发性口腔溃疡（ROU）大鼠的治疗作用及其对黏膜炎症因子和机体免疫功能的影响。方法: 选取SPF级Wistar雄性大鼠60只,随机数字表法将大鼠分成6组,分别为益气养阴生肌方低、中、高剂量组、正常组、模型组及阳性对照组,每组各10只,除正常组外其他各组大鼠制备ROU模型,成功造模后,益气养阴生肌方低、中、高剂量组分别给予0.17 mg/kg、0.34 mg/kg、0.68 mg/kg的益气养阴生肌方药液,阳性对照组灌胃布洛芬药液,正常组和模型组灌胃生理盐水,1次/d,连续灌胃10 d。观察各组大鼠溃疡数量、持续、间隔时间及溃疡面积,检测各组大鼠血清白细胞介素-2R（IL-2R）、IL-1β、IL-17、γ-干扰素（IFN-γ）、IL-2、转化生长因子-β1（TGF-β1）、表皮生长因子、血管内皮生长因子（VEGF）及T淋巴细胞含量,同时检测溃疡组织内NLRP3 mRNA相对表达量和基质金属蛋白酶-9（MMP-9）、MMP-2蛋白表达情况。 结果: 给药后2、6、10 d时阳性对照组、益气养阴生肌方中、高剂量组大鼠溃疡面积低于模型组,益气养阴生肌方中、高剂量组溃疡面积低于阳性对照组,差异均有统计学意义（P＜0.05）;和正常组相比,模型组大鼠血清IL-2R、IL-17、IL-1β及IFN-γ含量上升,血清IL-2含量下降;和模型组相比,阳性对照组、益气养阴生肌方中、高剂量组大鼠血清IL-2R、IL-17及IFN-γ含量下降,血清IL-2含量上升,差异均有统计学意义（P＜0.05）;和正常组相比,模型组大鼠血清TGF-β1、EGF含量下降,血清VEGF含量,溃疡组织内NLRP3 mRNA相对表达量及MMP-9、MMP-2蛋白表达量上升;和模型组相比,阳性对照组、益气养阴生肌方中、高剂量组大鼠血清TGF-β1、EGF、VEGF含量上升,溃疡组织内NLRP3 mRNA相对表达量及MMP-9、MMP-2蛋白表达量下降,差异均有统计学意义（P＜0.05）。结论: 益气养阴生肌方可纠正ROU大鼠免疫功能紊乱,降低血清炎症因子含量,以起到治疗作用。     

联用芝麻素和维生素E抑制PI3K/AKT信号通路改善自发性高血压大鼠的左室纤维化

目的：观察芝麻素（Ses）和维生素E（VitE）联用对自发性高血压大鼠（SHRs）左心室纤维化的影响,并探讨其可能机制。方法：14周龄雄性SHRs随机分为Ses和VitE联用组（160+10 mg·kg-1·d-1、Ses组（160 mg·kg-1·d-1）、VitE组（10 mg·kg-1·d-1）及SHRs组,另设正常对照WKY组,每组7只,1次/d持续灌胃给药10周。采用尾袖法测定大鼠给药前和给药10周后的收缩压。末次给药后取左心室,计算脏器指数,Masson染色观察胶原沉积,分析心肌胶原容积分数（CVF）,Western blot 观察Ⅰ型胶原（collagenⅠ）、Ⅲ型胶原（collagen Ⅲ）、转化生长因子β1（TGF-β1）、结缔组织生长因子（CTGF）、基质金属蛋白酶-9（MMP-9）、基质金属蛋白酶抑制剂-1（TIMP-1）、磷酸化蛋白激酶B（p-AKT）、蛋白激酶B（AKT）和磷酸肌醇3激酶（PI3K）蛋白的表达。结果：SHRs+Ses+VitE组的收缩压、HW/BW、LVW/HW、CVF明显下降,且下降幅度分别高于SHRs+Ses和SHRs+VitE组（P<0.01或P<0.05）。SHRs+Ses+VitE组的collagenⅠ、collagen Ⅲ、TGF-β1、CTGF、MMP-9、TIMP-1、p-AKT和PI3K蛋白表达明显下降,且下降幅度分别高于SHRs+Ses和SHRs+VitE组（P<0.01或P<0.05）。 结论：联用芝麻素和维生素E通过抑制AKT/PI3K信号通路的激活,减少TGF-β1、CTGF、MMP-9及TIMP-1表达,从而发挥降压和改善左心室纤维化的作用。     

羧胺三唑对角叉菜胶诱导急性炎症的抗炎作用

目的: 探讨羧胺三唑(CAI)对角叉菜胶诱导的大鼠足爪急性炎症的预防作用及部分机制。方法: 采用角叉菜胶诱导大鼠足爪急性炎症模型,测量足爪肿胀度以及足爪组织中髓过氧化物酶(MPO)、NO、前列腺素2(PGE₂)、TNF-α、IL-1β、中性粒细胞趋化因子-1(CNCI-1)和诱导一氧化氮合酶(iNOS)。结果: CAI能明显减轻大鼠足爪炎性肿胀,显著降低炎症足爪中MPO、NO、PGE₂、TNF-α、IL-1β和CNCI-1含量及iNOS蛋白表达。结论: CAI可能通过减少炎症介质和中性粒细胞浸润来发挥对角叉菜胶诱导急性炎症的抗炎作用。     

槲皮素对奈瑟球菌感染脑膜炎大鼠继发内毒素血症的抑制作用及机制研究

目的:分析槲皮素对奈瑟球菌感染脑膜炎大鼠继发内毒素血症的抑制作用影响。方法:选取SPF级Wistar雄性大鼠60只，随机数字表法将大鼠分成6组，分别是模型组、正常组、阳性对照组、低剂量槲皮素组、中剂量槲皮素组及高剂量槲皮素组，每组各10只，除正常组大鼠外，其他大鼠制备奈瑟球菌感染脑膜炎模型，造模后阳性对照组灌胃2 mL剂量为100 mg/L的地塞米松药液，低、中、高剂量槲皮素组灌胃2 mL剂量为50、100、200 mg/L的槲皮素药液，正常组与模型组大鼠灌胃等剂量生理盐水，各组大鼠给药间隔12 h，共给药5次。观察各组大鼠给药12、24、36、48及60 h时其存活率状况，同时间隔12 h检测大鼠体温一次，ELISA法检测血清IL-6、TNF-α、脂多糖、IL-1β、IL-8含量，Western blot检测p65与IκBα蛋白表达，RT-PCR检测脑组织Toll样受体4（TLR4）mRNA、CD68 mRNA相对表达量。结果:造模24 h内模型组大鼠全部死亡，模型组大鼠存活率低于正常组，中剂量及高剂量槲皮素组大鼠存活率优于模型组、阳性对照组及低剂量槲皮素组，差异有统计学意义（P＜0.05）；模型组大鼠血清IL-6、TNF-α、IL-1β及IL-8含量显著高于正常组（P＜0.05），其他各给药组血清IL-6、TNF-α、IL-1β及IL-8含量显著低于模型组。其中，中、高剂量槲皮素组大鼠降低显著，和模型组、阳性对照组对比差异有统计学意义（P＜0.05）。模型组大鼠IκBα蛋白表达比正常组下降，p65蛋白表达比正常组上升，中、高剂量槲皮素组大鼠IκBα蛋白表达比模型组、阳性对照组上升，p65蛋白比模型组、阳性对照组下降，差异均有统计学意义（P＜0.05）。结论:槲皮素可抑制奈瑟球菌感染脑膜炎大鼠机体NF-κB炎症通路，降低血清炎性因子含量，提高大鼠存活率。     

染料木素调控JAK2/STAT3信号通路改善骨性关节炎大鼠软骨代谢的作用研究

目的:在大鼠骨性关节炎（OA）模型中观察染料木素通过酪氨酸蛋白激酶2/信号转导子和转录激活子3(JAK2/STAT3)信号通路对骨性关节炎软骨代谢的作用。方法:SD大鼠随机分为3组,相应处理6周后取材,采用组织学染色的方法观察软骨标本的组织学形态、ELISA检测大鼠关节液中TNF-α表达水平、Western blot检测关节软骨细胞中p-JAK2、p-STAT3、MMP-13、Bax、Bcl-2相关蛋白的表达。结果:染料木素能有效增加OA关节软骨的胶原及蛋白多糖含量,使软骨组织结构接近正常软骨。与OA组相比,染料木素+OA组的TNF-α表达显著下调（P<0.01）,与正常组相近（P>0.05）。与OA组相比,染料木素+OA组的p-JAK2、p-STAT3及Bcl-2蛋白表达水平明显上升、MMP-13、Bax蛋白表达水平明显下降（均P<0.05）。结论:JAK2/STAT3信号通路与骨性关节炎软骨退变的病理过程密切相关,染料木素可激活JAK2/STAT3信号通路,抑制骨性关节炎炎症反应,抑制软骨细胞的凋亡,明显缓解关节软骨的退变,降低OA进展水平。     

刺芒柄花素对去势骨质疏松大鼠P38MAPK/MMP-9信号通路的影响

目的:观察刺芒柄花素（formononetin,FOR）对大鼠去势骨质疏松的干预作用,探讨其防治骨质疏松的机制。方法:采用切除雌性大鼠双侧卵巢法复制骨质疏松大鼠模型,按随机对照分组原则将60只清洁级SD雌性大鼠分为对照组、骨质疏松模型组、雌二醇组(50 μg/kg)及刺芒柄花素高、中、低剂量组(160、80、40 mg/kg),每组10只,除对照组外,其他组于造模后一周给予雌二醇、刺芒柄花素治疗,每天1次,连续12周,末次给药后24 h,取大鼠血清检测酒石酸酸性磷酸酶（TRACP）、Ca2+、Mg2+等指标变化;取大鼠左侧股骨采用RT-PCR检测基质金属蛋白酶-9（MMP-9）、TNF-α、IL-6 mRNA表达;Western blot法检测骨组织总P38MAPK、磷酸化P38MAPK、MMP-9、TNF-α、IL-6蛋白表达;取右侧股骨进行骨密度(bone mineral density,BMD)测定。结果:与骨质疏松模型组比较,刺芒柄花素高、中剂量组可增加骨质疏松大鼠骨密度,降低骨质疏松大鼠血清中TRACP含量,升高血清 Mg2+、Ca2+含量,使骨组织MMP-9、TNF-α、IL-6 mRNA和蛋白表达下调;磷酸化P38MAPK mRNA蛋白表达上调。结论:刺芒柄花素对去势骨质疏松大鼠有较好的防治作用,其机制可能与抑制骨组织MMP-9的合成和分泌、破骨细胞的骨吸收及调控P38MAPK/MMP-9 信号通路有关。     

氟伐他汀对心衰大鼠基质金属蛋白酶、转化生长因子及左室重构的影响

目的: 了解基质金属蛋白酶-2(MMP-2)及转化生长因子-β₁(TGF-β₁)在心肌梗死大鼠左室重构及心衰发展过程中的改变,以及氟伐他汀的干预作用,探讨心梗后心衰的发生机制。方法: 选用雄性SD大鼠67只随机分为假手术组、心梗组和心梗他丁组,经冠状动脉前降支结扎术建立心肌梗死后心衰模型,手术24 h后心梗他汀组大鼠管饲氟伐他汀4 mg·kg^-1·d^-1,假手术组和心梗组大鼠管詞安慰剂。术后3 d、4周、8周检测大鼠非梗死区心肌MMP-2 的含量（Westem-blot 法）、胶原、TGF-β₁的改变（免疫组化法）,压力传感器记录左室血流动力学改变。结果: 术后各时点非梗死区心肌的MMP-2含量,心梗组及心梗他汀组显著高于假手术组（P <0.05),而心梗他汀组显著低于心梗组（P<0.05);术后各组各时点非梗死区心肌TGF-的表达的变化趋势与MMP-2相同;与心梗组比较,心梗他汀组术后4周和8周的心功能明显改善,股原容积分数(CVF)及 I/III 型脱原比值（Ratio of type I/HI)降低(P<0.05)。结论: 氟伐他汀通过减少非梗死区心肌MMP-2和TGF-J3,的含量,而减轻心梗后非梗死区心肌胶原网络的破坏及反应性胶原的过度沉积,从而子页防和逆转心室重构,改善心脏功能。     

牛磺酸对心肌缺血再灌注大鼠模型心肌损伤的保护作用

目的: 观察牛磺酸（taurine,Tau）预处理对大鼠心肌缺血再灌注后炎症因子白介素-6（IL-6）、C反应蛋白（CRP）及内质网应激相关蛋白蛋白激酶R样内质网激酶（PERK）、增强子结合蛋白（CHOP）、磷酸化c-Jun氨基末端蛋白激酶（p-JNK）及Caspase-12表达的影响,探讨其对心肌细胞缺血再灌注损伤的保护作用及作用机制。方法: 三月龄SD大鼠96只,随机分为正常对照组、假手术组、模型组、Tau干预组,每组24只。于造模成功后的第12 h、1 d、2 d、3 d取心脏血液及心肌组织,采用ELISA试剂盒检测各组大鼠血液中IL-6、CRP的变化情况;应用免疫蛋白印迹法检测PERK、CHOP、p-JNK及Caspase-12蛋白的表达水平。结果: 模型组IL-6、CRP的表达水平在各时间点明显高于正常对照组（P＜0.05）;Tau干预组与模型组比较,IL-6、CRP的水平呈下降趋势,IL-6水平于时间点1、2、3 d差异有统计学意义（P＜0.05）,CRP于各时间点差异均有统计学意义（P＜0.05）。模型组PERK表达于2 d达到峰值;Tau干预组与模型组比较,PERK表达在各时间点均降低（P＜0.05）,但仍高于正常对照组。模型组CHOP在造模后各时间点的表达均增加,于2 d达到峰值;Tau干预组与模型组比较,CHOP在时间点1、2、3 d的表达降低,差异有统计学意义（P＜0.05）。模型组、Tau干预组p-JNK的表达于12 h达到峰值,其后呈下降趋势,但仍显著高于正常对照组（P＜0.05）,Tau干预组p-JNK水平与模型组相比显著降低,在时间点1、2 d时差异有统计学意义（P＜0.05）。模型组Caspase-12的表达增加,于2 d达到峰值。Tau干预组与模型组比较,Caspase-12的表达降低,在各时间点差异均有统计学意义（P＜0.05）。结论: Tau预处理可通过抑制PERK、CHOP、p-JNK及Caspase-12蛋白表达,发挥其对心肌缺血再灌注的细胞保护作用。     

芪藤消浊颗粒介导miR-339-5p对慢性肾小球肾炎大鼠炎症指标的影响

目的：探讨芪藤消浊颗粒通过miR-339-5p对慢性肾小球肾炎（chronic glomerulonephritis, CGN）大鼠炎症指标的影响。方法：大鼠尾静脉注射阿霉素制备CGN模型，用芪藤消浊颗粒（21.6、10.8、5.4 g/kg）连续灌胃30 d，通过HE染色和电镜观察CGN大鼠肾脏组织中的病理变化情况，qRT-PCR、ELISA、Western blot检测大鼠血清及肾脏组织中的IL-1β、IL-6、IL-10、TNF-α的含量，Western blot检测miR-339-5p、Syk、p-Syk蛋白相对表达量，qRT-PCR检测miR-339-5p mRNA及Syk mRNA的相对表达量。结果：模型组大鼠出现基底膜增厚，肾小球萎缩等病变，与正常组相比，模型组大鼠的miR-339-5p和IL-10表达明显下调，IL-1β、IL-6、TNF-α、Syk的表达显著上调，芪藤消浊颗粒组可显著降低肾脏组织中IL-1β、IL-6、TNF-α、Syk的蛋白及mRNA的表达水平。 结论：芪藤消浊颗粒治疗CGN大鼠的炎症症状可能是通过miR-339-5p下调炎症因子的表达水平。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Thermodynamics Study on the Decomposition of Chromite with KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

Influence of Heat Treatment on Damping Behaviour of the Magnesium Wrought Alloy AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.     

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.     

电化学噪声数据处理方法概述

综述了常见的电化学噪声数据处理方法,介绍了直流趋势剔除、统计分析、快速傅立叶变换(FFT)法计算功率谱密度(PSD)以及小波变换处理电化学噪声信号的基本过程,并阐释了各种数学处理及所得参数的物理意义。