A Simple Method for Fabrication of Bionic Superhydrophobic Zinc Coating with Crater-like Structures on Steel Substrate

Surface modification with superhydrophobicity is a popular and challenging research field on metals. In this work, a simple method was used to fabricate a bionic superhydrophobic zinc coating with crater-like structures on pipeline steel surface. This method involved electrodeposition of zinc coating and chemical reaction in perfluorooctanoic acid ethanol solution. The per- fluorooctanoic acid with low surface free energy was not only used for chemical etching but also used for fluorinated modifi- cation. The contact angle of water on such superhydrophobic zinc coating was up to 154.21°, and the sliding angle was less than 5° due to the micro crater-like structures and the low surface free energy. Moreover, the prepared superhydrophobic zinc coating demonstrated excellent self-cleaning property and great stability at room temperature, and the contact angle of water on this coating remained stable after storage in air for more than 80 days. This superhydrophobic zinc coating will open much wider applications of electrodeposition metal coating, including self-cleaning property, and can be easily extended to other metals.

食管克罗恩病内镜特征分析

目的探讨食管克罗恩病(Esophageal Crohn′s disease,ECD)的人口学特点及胃镜下病变特征。方法回顾性分析我院2007年1月～2011年12月期间经上消化道内镜检查同时经活检组织病理学诊断并最后经综合评价诊断为ECD病例的胃镜特点。结果 57例ECD患者中男性32例(56.1%),女性25例(43.9%),平均发病年龄(40.6±11.6)岁,ECD在男女性别中的检出率差异没有统计学意义(χ2=2.092,P=0.148),内镜下溃疡形态主要为纵行溃疡24例(42.1%)、火山口样溃疡21例(36.8%)、鹅口疮样溃疡14例(24.6%)、环形溃疡4例(7.0%),胃镜下ECD患者食管溃疡分布状况表现为跳跃性分布30(52.6%)例,呈单发分布24(42.1%)例;食管上段、食管中段及食管下段受累比例分别为:12.3%63.2%36.8%。结论食管克罗恩病好发于中青年人群,发病未见性别差异,胃镜下病变特征呈非特异性,主要累及食管中段,火山口样溃疡在食管较为多见,胃镜检查有助于食管克罗恩病受累程度及范围的评估。本研究为CD的诊断、鉴别提供了依据和指导。

小行星形貌特征的分析与描述

小行星形貌特征的分析对深空探测器的导航、着陆点的选取具有重要意义。现有的深空星体形貌特征的分析与描述主要集中在火星、月球等类地天体上,而作为宇宙中为数众多、信息量丰富的小行星却鲜有文献对其形貌特征作详细深入的介绍。文章以Vesta、Eros、Mimas等人类已探测的小行星为例,分析了几种典型的小行星表面形貌特征,完善了凹坑、岩石等形貌特征的描述参数,并用仿真实验生成了Mimas小行星表面的Herschel凹坑模型。实验结果显示,所提出的特征描述方法具有较好的仿真度和实用性。