“断亲”还是“疏亲”:当代农村青年的亲缘关系状况

自“断亲”概念被提出以来,青年“断亲”成为近年来网络上热议的话题,但用“断亲”来描述当代青年亲缘关系的准确度有待商榷。“疏”相对于“断”表示程度更浅,既有血缘关系的日渐淡薄,也有渐行渐远、似断非断的意味,更符合青年群体的实际状况。文章结合农村青年亲缘关系现状调查,提出青年“疏亲”是带有乡土特性的、是相对的而非绝对的、是阶段性的而非长期性的、是全年龄段的而非青年独有的等特征,呼吁社会大众对青年“疏亲”给予更多的理解,理性看待这一现象。

Bioinspired superwetting surfaces for fog harvesting fabricated by picosecond laser direct ablation

Fog harvesting has been considered as a promising method for solving water crisis in underdeveloped regions.To mimic and optimize the alleged natural fog harvesting ability of the stenocara beetle,hybrid superhydrophobic(hydrophobic,superhydrophilic)/hydrophilic patterns are processed on stainless steel via picosecond laser direct writing.Basically,after laser processing,the surfaces of stainless steel change from hydrophilic to superhydrophilic.Then,after chemical and heat treatment,the superhydrophilic surfaces become superhydrophobic with ultra-low adhesion,and superhydrophobic(hydrophobic)with ultra-high adhesion,respectively.This work systematically examines the fog harvesting ability of picosecond laser treated surfaces(LTS),pristine surfaces(PS),laser and chemical treated surfaces(LCTS),laser and heat-treated surfaces(LHTS).Compared with the PS,the as-prepared surfaces enhanced the fog harvesting efficiency by 50%.This work provides a fast and simple method to fog collectors,which offer a great opportunity to develop water harvesters for real world applications.

Synthesis of Amphiphilic Polyelectrolyte and Study of Their Association Behavior in Hydroalcoholic Media

The objective of the work involves the synthesis of comb-like amphiphilic cationic polymers with repeating units methacylamides laterally substituted by a group containing a quaternary ammonium site and a hydrophobic n-alkyl side chain with 8-10 carbon atoms. Two synthesis methods were developed successfully. The first method is consisted to synthesizing first amphiphilic cationic methacrylamide monomers. In the second method the tertiary amine groups of polymers precursors were quaternised with various n-alkyl bromides. All the polymers obtained in this way were characterized by spectroscopic methods： 1^H NMR and by viscometry. The reduced viscosity of hydro-alcoholic polymer solution decreases with polymer concentration. Viscometry study showed that these polymers display typical polysoap behavior in hydro-alcoholic mixtures.

Interactions Mode of Amphoteric Molecules with Ordered Phospholipid Membrane

Aim To explore interaction mode between amphoteric molecules with the orderedphospholipid membrane. Methods Membrane interactions were determined by immobilized artificialmembrane (IAM) chromatography and solutes' hydrophobicity was measured by n-octanol/buffer system.Results The ampholytes, similar to bases, generally exhibited higher membrane affinity than expectedfrom their hydrophobicity, resulting from the attractive polar interaction with phospholipidmembrane. Furthermore, the strength of additional polar interaction with membrane (Δlg k_(IAM)) wasthen calculated. The Δlg k_(IAM) values were far greater for bases and ampholytes ranging from0.50 - 1.39, than those for acids and neutrals with the scope from - 0.55 - 0.44. ConclusionConsidering the microspecies distribution of amphoteric molecules, it was assumed that not onlyneutral and positive but also zwitterionic microspecies are capable of partitioning into orderedamphoteric lipid membrane with complementarily conformational and energetically favorableinteractions.

Molecular Dynamics Simulation of Effect of Salt on the Compromise of Hydrophilic and Hydrophobic Interactions in Sodium Dodecyl Sulfate Micelle Solutions

The presence of salt has a profound effect on the size,shape and structure of sodium dodecyl sulfate(SDS)micelles.There have been a great number of experiments on SDS micelles in the presence and absence of salt to study this complex problem.Unfortunately,it is not clear yet how electrolyte ions influence the structure of micelles.By describing the compromise between dominant mechanisms,a simplified atomic model of SDS in presence of salt has been developed and the molecular dynamics(MD)simulations of two series of systems with different concentrations of salt and charges of ion have been performed.Polydispersity of micelle size is founded at relatively high concentration of SDS and low charge of cation.Although the counter-ion pairs with head groups are formed,the transition of micelle shape is not observed because the charge of cation is not enough to neutralize the polar of micelle surface.

Fabrication of superhydrophilic surface on copper substrate by electrochemical deposition and sintering process

Superhydrophilic surfaces were fabricated on copper substrates by an electrochemical deposition and sintering process. Superhydrophobic surfaces were prepared by constructing micro/nano-structure on copper substrates through an electrochemical deposition method. Conversion from superhydrophobic to superhydrophilic was obtained via a suitable sintering process. After reduction sintering, the contact angle of the superhydrophilic surfaces changed from 155° to 0°. The scanning electron microscope （SEM） images show that the morphology of superhydrophobic and superhydrophilic surfaces looks like corals and cells respectively. The chemical composition and crystal structure of these surfaces were examined using energy dispersive spectrometry （EDS） and X-ray diffraction （XRD）. The results show that the main components on superhydrophobic surfaces are Cu, Cu2O and CuO, while the superhydrophilic surfaces are composed of Cu merely. The crystal structure is more inerratic and the grain size becomes bigger after the sintering. The interracial strength of the superhydrophilic surfaces was investigated, showing that the interfacial strength between superhydrophilic layer and copper substrate is considerably high.

A facile method to fabricate surfaces showing superhydrophilicity in air and superhydrophobicity in oil

The changes of the wettability of the solid surfaces have attracted massive attention due to their important practical implications in numerous fields. As a new subject, the research on the wettability under the different environments is still in its early stage. So the fundamental research must be performed for the practical applications under different environments. However, it is seldom that the comprehensive wettability of a surface in air, in water and in oil has been reported. In this paper, the authors investigated the wettability of the stainless steel mesh coated with polyurethane in the above three different environments. The surface of the uncoated mesh was found to be hydrophobic in air, but the surface of the coated mesh was superhydrophilic in air. More interestingly, the surfaces of the coated meshes were superoleophilic in water and superhydrophobic in oil. Due to the coated meshes with these wettabilities were fabricated via a facile two-step method, the presented method may be adopted for large-scale industrial production, in various fields, such as icing prevention or the oil-field industry.