矿物表面特性与可浮性关系综述

综述了矿物某些表面特性：表面化学组成、异向性表面、表面能的结构、表面电性、表面不均匀性和表面溶解性与可浮性之间的关系,井深入研究进行了展望．     

低冰粘附强度表面设计与制备研究进展

表面结冰给通讯、电力等工业领域带来巨大损失,电加热和喷洒乙二醇等主动除冰方法虽然在一定程度上可以解决上述问题,但在能源、人力、环境方面需付出较高代价。为解决这一问题,低成本、低能耗的被动式防/除冰表面被寄予厚望。防/除冰表面主要分为延长结冰时间的防冰表面和低冰粘附强度的除冰表面。由于实际工况的复杂性,除冰表面比防冰表面更具有可实现性。除冰表面主要与低表面能、界面滑动和裂纹产生相关,低冰粘附强度表面按实现机理可分为化学改性低表面能表面、润滑表面、界面滑动表面和裂纹源表面。本文对不同类型低冰粘附表面的低冰粘附强度产生的原因和表面的制备方法进行总结。同时,对冰粘附强度的测量标准进行了说明和讨论,以解释不同的测试方法对防/除冰性能测试结果造成的差异。      

新的轧制压花不锈钢表面

蒂森克虏伯尼洛斯塔公司已经开始推销6种新的轧制压花不锈钢表面。在过去30年中，4种表面加工一直在市场上占据优势，它们是：布纹表面、钻石花表面，方形图案表面和皮革纹表面。蒂森克虏伯尼洛斯塔公司的新型表面分别叫做微米条纹表面(Microchecker)，微米布纹表面Microlinen)，奥氏体结构表面(Austenite)，三角形花纹表面(Friangles)，瀑布纹表面(Water-fall)和雾纹表面(Haze)。其中微米条纹表面，微米布纹表面，雾纹表面和奥氏体结构表面已经小面积开发成功，而三角形花纹表面和瀑布纹表面适用于较大面积的用途。     

钛合金表面强化新进展

介绍了为改善钛合金表面耐磨性将激光表面熔敷、高能微弧火花渗碳和表面渗氧技术应用于钛合金表面强化所取得的进展。讨论了每种工艺方法所获表面改性层的结构和性能特征及其应用范围。     

涂层技术及其应用

在选择一种涂层技术时应该考虑到涂层技术的经济性和技术性能,要在整个系统中考虑到表面涂层或其他表面改性和处理的方法,要知道表面要求的功能、服务环境、基材(合金、热处理等)所处理表面的性能,必须考虑到涂层自身的技术问题和经济性,涂层的使用寿命和优点,而不仅仅是涂层的生产成本。1表面处理方法分类涂层可以有许多方法来分类,一种方法基于如何把涂料敷到表面上或怎样对表面进行改性,可以按下面方法来分类,即原子沉积(atomisticdeposition)、粒子沉积(particulatedeposition)、粉末涂层(bulkcoating)和表面改性(surfacemodifi-cation)…     

铣削加工对医用AZ31B镁合金表面完整性的影响

镁合金作为植入体材料其表面完整性对腐蚀速率有重要影响,使用干铣削机械加工对AZ31B镁合金展开表面改性研究,揭示铣削加工参数对表面完整性的影响规律。用表面粗糙度、表面润湿性和表面硬度为指标来表征表面完整性,通过正交干铣削实验探索切削速度、进给量以及背吃刀量铣削工艺参数对AZ31B镁合金表面完整性的影响。     

U75V热轧钢轨表面氧化铁皮显微分析

利用光学显微镜、扫描电镜及能谱对U75V热轧钢轨表面氧化铁皮的表面形貌、截面形貌、氧化铁皮厚度、组织成分进行了观察和测量,并讨论了钢轨和板带表面氧化铁皮厚度及形貌差异的原因。研究表明,U75V热轧钢轨表面氧化铁皮具有典型的由内到外分别为FeO、Fe_3O_4和Fe_2O_3氧化物的三层结构,在内层FeO与基体界面处存在Si元素的富集;钢轨表面氧化铁皮平均厚度达50μm以上,下表面氧化铁皮厚度大于上表面;钢轨和板带表面氧化铁皮厚度及形貌的差异主要与二者断面形状和生产工艺的差异有关。     

钛合金表面强化新进展

介绍了为改善钛合金表面耐磨性将激光表面熔敷、高能微弧火花渗碳和表面渗氧技术应用于钛合金表面强化所取得的进展.讨论了每种工艺方法所获表面改性层的结构和性能特征及其应用范围.     

钨矿表面特性与可浮性关系研究现状

钨矿选别过程中,黑、白钨矿分别主要采用重选法和浮选法回收.但因为重选难以高效回收微细粒黑钨矿以及浮选过程中白钨矿难以与含钙矿物有效分离等原因,导致钨矿回收率低或品位不理想.因此,有必要对黑、白钨矿的表面特性进行深入研究.介绍了黑、白钨矿表面特性的研究现状,主要评述了黑、白钨矿表面键的断裂、表面化学组成、表面异向性、表面电性以及表面溶解组分对钨矿可浮性的影响.对未来钨矿表面特性的研究方向和研究方法进行了展望.     

表面处理材料的腐蚀性能

为了使金属材料具有良好的抗水腐蚀和抗氧化性能以及耐磨损性能,对材料表面进行处理,使其生成亚稳态合金,非晶结构,获得适宜的表面应力状态和均匀的表面电光特性。表面处理可采用激光表面合金化(LSA)、离子注入、离子沉积涂层等方法。     

1950MPa级弹簧钢55SiCrA疲劳断口夹杂物来源分析

采用SEM-EDS对1950 MPa级油淬火钢丝Nakamura旋转弯曲疲劳断口和弹簧疲劳断口宏观夹杂物的成分及尺寸分布进行检测,借助ASPEX Explorer自动扫描电镜对弹簧钢55SiCrA盘条显微夹杂物成分、尺寸及分布进行检测统计。通过对比发现,疲劳断口宏观夹杂物与钢中显微夹杂物成分近乎一致,表明其主要来源为脱氧产物和钢渣反应产物。并根据断口夹杂物的尺寸分布特点推测此疲劳条件下夹杂物的临界尺寸为20μm,最后指出采用夹杂物的塑性化生产工艺,借助结晶器流场优化提高铸坯表层洁净度是后续改进方向。     

冷拔60Si2MnA弹簧钢制簧过程的断裂分析

Φ11.8mm冷拔60Si2MnA弹簧钢(/%:0.58C,1.77Si,0.79Mn,0.15Cr,0.015P,0.005S)的生产流程为80 t LD-LF-VD-热轧至Φ12 mm盘条-冷拔工艺。对卷簧时断裂弹簧进行金相、力学、组织分析表明,热轧材表面质量和冷拔后弹簧钢的力学性能良好,钢中存在20μm以上大颗粒非金属夹杂和冷拉过程产生的表面划痕是卷簧时弹簧断裂的诱因;控制钢中大颗粒夹杂物产生和改善冷拔润滑避免拔制过程产生深的划痕,可防止断裂发生。     

60CrMnA弹簧扁钢的试制

采用转炉-精炼-连铸-型材轧机工艺流程试制60CrMnA弹簧扁钢。通过采取拉碳法、LF精炼及喂丝、保护浇铸和轧制合理控制冷却等措施，解决了生产中存在的扁钢硬度高、表面毛刺、侧面裂纹等问题，生产出了符合GB1222—84标准和满足用户要求的60CrMnA优质弹簧扁钢。     

The Role of Changes in the Annual Cycle in Earlier Onset of Climatic Spring in Northern China

Climatic changes in the onset of spring in northern China associated with changes in the annual cycle and with a recent warming trend were quantified using a recently developed adaptive data analysis tool, the Ensemble Empirical Mode Decomposition. The study was based on a homogenized daily surface air temperature (SAT) dataset for the period 1955-2003. The annual cycle here is referred to as a refined modulated annual cycle (MAC). The results show that spring at Beijing has arrived significantly earlier by about 2.98 d (10 yr)-1, of which about 1.85 d (10 yr)-1 is due to changes in the annual cycle and 1.13 d (10 yr)-1 due to the long-term warming trend. Variations in the MAC component explain about 92.5% of the total variance in the Beijing daily SAT series and could cause as much as a 20-day shift in the onset of spring from one year to another. The onset of spring has been advancing all over northern China, but more significant in the east than in the west part of the region. These differences are somehow unexplainable by the zonal pattern of the warming trend over the whole region, but can be explained by opposite changes in the spring phase of the MAC, i.e. advancing in the east while delaying in the west. In the east of northern China, the change in the spring phase of MAC explains 40%-60% of the spring onset trend and is attributable to a weakening Asian winter monsoon. The average sea level pressure in Siberia (55°-80°N, 50°-110°E), an index of the strength of the winter monsoon, could serve as a potential short-term predictor for the onset of spring in the east of northern China.     

汽车悬架用弹簧钢55SiCr制备技术的研究进展

悬架弹簧钢是汽车悬架系统的重要部件,研发高性能汽车悬架弹簧钢制备技术对于推动特殊钢材料的国产化有着重要的意义。从洁净度控制、组织性能调控和表面脱碳控制3个方面介绍近年来汽车悬架弹簧钢55SiCr制备技术的最新进展。在洁净度控制上,对弹簧钢中夹杂物的控制方向、脱氧工艺、精炼渣和耐火材料等相关研究进行介绍。在组织性能调控中,重点介绍作者所在研究所在悬架弹簧钢55SiCr热处理工艺改进与优化上的探索,比较了淬火-回火、等温淬火和淬火-配分工艺对悬架弹簧钢55SiCr力学性能的影响。表面脱碳控制的相关研究表明,在进行热处理或热加工的过程中,应尽量避免在低于弹簧钢奥氏体/铁素体转变温度(约800 ℃)附近停留,虽然较高的温度有利于避免全脱碳,但是出于晶粒粗化、能耗和氧化等方面的考虑,热处理温度不宜高于1 100 ℃。     

Interdecadal Variability in Surface Solar Radiation over Northwest China and Its Possible Cause

The present study investigates the interdecadal variability of seasonal mean surface solar radiation over Northwest China using station observations from 1961-2003. Spring and summer surface solar radiation over Northwest China was lower in the late 1970s through 1990s than in the 1960s through the mid-1970s, and fall and winter surface solar radiation displayed similar patterns. These results indicate that the decrease in spring and summer surface solar radiation may be associated with increased low-cloud cover over Northwest China. Rainfall anomalies were closely related to the low-cloud cover over Northwest China and with the Northern Hemisphere circumglobal teleconnection in spring, summer, and winter.     

Simulations of the erythrocyte cytoskeleton at large deformation. I. Microscopic models

Three variations of a polymer chain model for the human erythrocyte cytoskeleton are used in large deformation simulations of microscopic membrane patches. Each model satisfies an experimental observation that the contour length of the spectrin tetramers making up the erythrocyte cytoskeleton is roughly square root of 7 times the end-to-end distance of the tetramer in vivo. Up to modest stress, each brushy cytoskeletal network behaves, consistently, like a low-temperature, planar network of Hookean springs, with a model-dependent effective spring constant, keff, in the range of 20-40 kBT/s(o)2, where T is the temperature and s(o) is the force-free spring length. However, several features observed at large deformation distinguish these models from spring networks: 1) Network dimensions do not expand without bound in approaching a critical isotropic tension (square root of 3 keff) that is a characteristic limit of Hookean spring nets. 2) In surface compression, steric interactions among the chain elements prevent a network collapse that is otherwise observed in compression of planar triangulated networks of springs. 3) Under uniaxial surface tension, isotropy of the network disappears only as the network is stretched by more than 50% of its equilibrium dimensions. Also found are definitively non-Hookean regimes in the stress dependence of the elastic moduli. Lastly, determinations of elastic moduli from both fluctuations and stress/strain relations prove to be consistent, implying that consistency should be expected among experimental determinations of these quantities.     

钒氮微合金化对Si-Mn系弹簧钢热处理特性的影响

分别采用VN、Fe—V合金在实验室冶炼了不同钒含量的Si—Mn系弹簧钢，并系统研究了其淬透性、抗回火稳定性、表面脱碳敏感性和力学性能的变化情况。结果表明，本试验条件下，采用钒氮微合金化的Si—Mn系弹簧钢(0．50％C，0．06％-0．10％V，0．01％N)具有较好的淬透性和抗回火稳定性。钒含量增加，强度显著增加。钒氮微合金化对表面脱碳敏感性没有明显影响。     

表面缺陷对高强度弹簧钢弯曲疲劳性能的影响

本文叙述了带表面纵向裂纹的６０Ｓｉ２ＣｒＶＡ弹簧钢带的弯曲疲劳试验和结果分析，发现表面纵向裂纹对弯曲疲劳性能影响大，而表面微坑等点状缺陷具有更大的危害性。     

Soil Spring Constants of Buried Pipelines for Seismic Design

This paper presents within the scope of the theory of static elasticity a derivation of soil spring constant in longitudinal direction of a buried pipeline in the seismic design. It is found that the spring constant depends on the shear modulus G of the soil deposits and the ratio λ of the radius of zero displacement over the radius of a buried pipeline structure. When λ increases, the soil spring constant decreases and the decreasing rate reduces remarkably when λ is greater than about 10. The ratio of soil spring constant over G is 2.7 when λ = 10. Furthermore, the dynamic effect of soil spring constants on buried pipeline structures is estimated analytically by the dynamic theory of elasticity. The soil spring constant that is derived, taking into account the boundary condition of ground surface, depends on the shear modulus G of the ground, nondimensional frequency ωb∕Vs (ω = circular frequency; b = radius of buried pipeline; Vs = ground shear-wave velocity) and nondimensional depth d∕b (d = depth of pipeline).