微信文学的价值体认

微信文学具有内化于文学文本、贯穿于文学活动中的丰富而独特的文学价值,正逐渐形成与传统文学相互扶持、与微博文学齐头并进的发展态势。其价值主要表现在:用"微"视角反映原本琐碎细杂、平淡无奇的生活,让微民生活融入时代主题;表现出当前时代的文化生态,为现存社会问题的提出与解决提供舆论力量和文化指引;应和当代人通过情感宣泄释放精神压力、实现自我宽慰的需要,便于对人们生活情感经历的多节点观察和潜意识心理的多向性挖掘;继续让文学写作回归民间大众,维护和关切人的尊严、价值、幸福,是人道主义当下立场与人生探索超越思维的有机结合。

Characterization of dynamic microstructural evolution of AA7150 aluminum alloy at high strain rate during hot deformation

The AA7150 aluminum alloy was compressed to various strains at strain rate of 10 s（-1） and temperatures of 300 °C and 450 °C, respectively. Flow stress behavior, substructure evolution, morphology and spatial distribution of precipitates were studied based on differential scanning calorimetry analysis and transmission electron microscope observation. The results showed that dynamic flow softening occurs during hot deformation. The main softening mechanism could be concluded as dynamic recovery at 300 °C and continuous dynamic recrystallization at 450 °C. The clear heterogeneous spatial distributions of precipitates are found during deformation and enhanced with increased strain. Higher contents of Cu in T phases are found at 450 °C than at 300 °C, which present a transformation process from T phases to S phases as well. The associated evidence of dynamic precipitation on dislocations and particle-stimulated nucleation, as well as the detailed microstructural inherited relationship and morphological texture（particles preferred orientation） were characterized.

The Application of Virtual Reality Technology to Ear Microsurgery

The broad application of virtual reality (VR) to medicine has been of great value. The virtual surgery is one of technically difficult applications. With the expansion of the increasingly fine and complicated ear microsurgery, new methods are required to train the doctors. It is necessary and of practical significance to apply VR to the ear micro-operation, which is a functional operation with high precision and great difficulties. In this article, medical VR applications were reviewed. The application of VR to the ear microsurgery was discussed and the virtual ear microsurgery system was designed.

Microscopic colitis: A retrospective study of clinical presentation in 53 patients

AIM: To evaluate the relationship between symptoms and microscopic colitis (MC) subtypes: to test whether collagenous colitis (CC) and/or lymphocytic colitis (LC)might be related to both constipation and diarrhea.METHODS: A cohort of patients with independently confirmed typical histopathological changes was investigated. Fifty-three patients with histologically proved MC (46 with CC, 7 with LC) were included. The existence of diarrhea or constipation and the co-existence of autoimmune diseases were also investigated and all data were retrospectively analyzed.RESULTS: Twenty-three (43.39%) of MC patients had chronic constipation (20 in CC, 3 in LC patients). Twentyfour(45.28%) of MC patients had autoimmune disease and the diagnosis of autoimmune disease was always prior to MC. Sjogren's syndrome was associated only with the constipation subgroup.CONCLUSION: The Janus face of MC resembles the subgroups of irritable bowel syndrome. The co-existence of autoimmune diseases and MC is confirmed in both the constipation and diarrhea subgroups.

Microstructure characteristics and liquation behavior of fiber laser welded joints of Mg-5Zn-1Mn-0.6Sn alloy sheets

Fine-grained Mg?5Zn?1Mn?0.6Sn alloy sheets of2mm in thickness were welded by fiber laser welding.The appearanceand microstructures of the welding joints and liquation behaviors in the partially melted zone(PMZ)were investigated.The resultsshow that,with the lower welding power and higher welding speed,the width and depth of the joints decrease.Moreover,some poresare detected at a very high welding speed.There are two kinds of liquation phenomena in the PMZ.One is the liquation networkalong grain boundaries associated with the liquation of substrate and segregation-induced liquation,the other is the molten poolinvolved with the liquation of the residual second phases at the boundaries.However,the liquation of substrate and thesegregation-induced liquation are the main liquation mechanism in the PMZ.

A collision detection approach in virtual environment of micromanipulation robot

Operators suffer much diffieulty in manipulating miero-size objects without the assistance of friendly interfaces due to the scaling effects in micro worht. The paper presented a general framework for mieromanipulation robot hased on virtual reality technology. With the framework we brought forward a FDH （Fixed Direction Hulls） based hounding box method to handle the eollision ,teteetion of the peg-in-hole mieroassembly. The eollision response model for the collision between micro needle and hole was presented. The virtual three and corresponding displacement were calculated with the model of bending deformation and pressing ,teformation. Experiments verify the validity of collision response model.

A control model for hysteresis based on microscopic polarization mechanisms in piezoelectric actuator

Aiming at the limitation of control accuracy caused by hysteresis and creep for a piezoelectric actuator, the hysteresis phenomenon is explained based on the microscopic polarization mechanism and domain wall theory. Then a control model based on polarization is established, which can reduce the hysteresis and creep remarkablely. The experimental results show that the polarization control method is with more linearity and less hysteresis compared with the voltage control method.

Variability of Carbonate Pedofeatures in a Loess-Paleosol Sequence and their Use for Paleoreconstructions

Carbonate pedofeatures were studied in details in a loess-paleosol pedocomplex near Kursk, in the central part of the European Plain. The soils studied included a modern Chernozem and five Pleistocene paleosols. Carbonate morphologies and distributions were described in the field. Various morphologies were sampled for further studies including micromorphology in thin sections and submicroscopic studies under a scanning electron microscope. The complex approach of investigation at macro-, micro-, and submicroscopic levels found that most of carbonate pedofeatures are secondary and multiphase. Many of them are related to cryogenic features. The general trend was of decreasing carbonate content in the older paleosols except for increased content in the 1St and 3rd paleosols. Most of carbonate morphologies are similar in the modern soil and paleosols, but pseudomycelium was found only in the modern Chernozem, while soft masses and impregnations are associated with the paleosols. Detailed study on carbonate attributes revealed their specific features in the modern soil and in paleosols. Veins have dissolution features under the modern environment and seem to reprecipitate in form of pseudomycelium. Coatings in paleosols at a depth of the Ist paleosol include specific fine tubes. Powdery soft masses and impregnations in the paleosols are strongly related to cryogenic fissures and paleopermafrost level. Under SEM they consist of tiny crystals, much smaller than in regular soft masses. Several types of hard concretions were identified：rounded, irregular and platy. Small concretions in the modern Chernozem have similar morphology and similar 14C-age as the rounded concretions of the upper paleosols. They are expected to represent the same generation of concretions. Platy concretions fill the bottom part of the large fissures. The 14C-age of hard concretions varies from 3310±80 yrs. B.P in the Ist paleosol up to 20 400 yrs. B.P. in the 3^rd. As a result we found the reflection of several wet-dry and cold-warm stages in carbonate morphologies and distributions. High variability of carbonates at macro-, micro- and submicroscopic levels indicates several generations and multiphase formation of carbonate pedofeatures in the loess-paleosol pedocomplex. Carbonate pedofeatures in the examined pedocomplex are more informative for the study of late Pleistocene and Holocene climatic cycles rather than characterization of a single paleosol.

Progress of electrode/electrolyte interfacial investigation of Li-ion batteries via in situ scanning probe microscopy

The electrode/electrolyte interface plays a cri- tical role in the performance of a Li-ion battery. In view of the dynamic and complex nature of the interface, in situ research approaches can provide valuable information of interfacial phenomena during battery operation. In situ scanning probe microscopy （SPM） is a powerful technique used for the interfacial investigation of the Li-ion batteries. The versatile SPM techniques and their various operation modes have been utilized to measure the morphology and other properties of the electrode interface at high resolu- tion. Herein, we discuss the related SPM techniques to study the topography, mechanics and electrochemistry re- search of electrodes. Recent progresses of in situ SPM research on the electrode/electrolyte interface are summa- rized. Finally, the outlook of the technique is discussed.