Mechanical properties of thermoelectric generators

To satisfy the requirements of practical applications,thermoelectric generators should be highly efficient and mechanically robust.Recently,progress in designing high-performance thermoelectric generators has been made.However,the mechanical properties of thermoelectric generators are still unsatisfactory.In this review,studies on the mechanical properties of thermoelectric generators are summarized.The me-chanical properties of bulk thermoelectric generators will be first discussed.In this section,the mechan-ical properties of thermoelectric materials and the strategies for improving their mechanical properties are emphasized.Since the device’s failure usually occurs at the interface between the thermoelectric ma-terials and electrode,the joint strength of electrodes and thermoelectric materials will be overviewed.After that,the mechanical properties of the inorganic thin-film thermoelectric devices will be discussed.Since the figure of merit for the flexibility of thermoelectric materials depends on the film thickness,elastic modulus,and yield strength,the synthesis methods of thin-film thermoelectric materials will be reviewed.Finally,this review will be concluded with a discussion on flexible organic thermoelectric de-vices and flexible devices using bulk legs.

白芍通过调控M2巨噬细胞极化有效缓解何首乌引发的特异质肝损伤

特异质药物性肝损伤(IDILI)是一种因药物引起的严重不良反应,通常发生在少数易感人群中。何首乌(PM)虽是一个常用的补益药,但许多临床数据已证明PM会引发IDILI。大多数IDILI的发生与机体免疫应激相关,然而对于PM导致IDILI的内在机制仍尚未被阐明。白芍(PRA)在临床上常与其他中药配伍,具有增效减毒缓解炎症等功效。但PRA是否能够缓解PM引发的肝损伤及内在机制仍未可知。在本研究中,通过网络药理学分析预测了PRA配伍PM在天然免疫中的相关靶点可能与巨噬细胞极化相关。同时采用非肝毒性剂量的LPS复制免疫应激模型,通过肝功能指标及病理等结果显示,当PM与PRA联用后,肝损伤的程度有所改善,相关促炎因子TNF-α和IL-6下降,M2巨噬细胞相关因子也有所上升。在体外,PM抑制了小鼠骨髓来源巨噬细胞(BMDMs)中IL-4诱导的Arg1及M2巨噬细胞标记物的表达,PRA则能够促进M2巨噬细胞极化,当二者配伍时,PRA可以改善PM对M2巨噬细胞极化的抑制作用。总之,这些研究结初步表明PRA能够通过促进M2巨噬细胞极化,降低炎症因子的表达,从而缓解PM引发的肝损伤,为解决何首乌引发的IDILI提供了新的思路和方案。

Performance evaluation of creep feed grinding ofγ-TiAl intermetallics with electroplated diamond wheels

This paper evaluates the performance of creep feed grindingγ-TiAl intermetallic(Ti-45 Al-2 Mn-2 Nb)using electroplated diamond wheels.Firstly,a comparative analysis with the grinding results by using electroplated CBN wheels was conducted,mainly involving abrasive wheel wear behavior and maximum material removal rate below surface burn limit.It was found that the diamond wheel would produce much better grinding results including lower wheel wear rate and higher maximum material removal rate.Then the surface integrity obtained at different level of material removal rate was characterized with the utilization of the diamond wheel.The poor ductility of thisγ-TiAl intermetallic material was found to have a marginal effect on the surface integrity,as no severe surface defects such as material pullout were generated during the stable wheel wear stage.For the involved operating parameters,a deformation layer was produced with~10μm or more in thickness depending on the material removal rate used.Meanwhile,a work-hardened layer extending to more than 100μm was produced with a maximum microhardness of above 520 HV0.05(bulk value 360 HV0.05).The residual stress remained compressive,with a value of above-100 MPa and even up to-500 MPa for an elevated material removal rate.Shearing chip was the main chip type,indicating good wheel sharpness in the grinding process.

From rock-boring organisms to tunnel boring machines:A new rock breaking technology by bioinspiration

The purpose of this study is to achieve better understanding of associated mechanisms and to recommend and identify new strategies to develop new rock breaking technology for Tunnel Boring Machines(TBMs).Tunnel Boring Machine tunnelling mainly depends upon the rock breakage caused by cutters moving on a rock surface in a rolling and sliding motion while under the action of thrust force.The rock breaking behaviour is controlled by the mechanical interaction between the cutters and the rock.Due to the high hardness and high abrasiveness of rock,the cutters have to work under very high thrust force and suffer heavy-load-impact and abrasive wear,causing serious wear and low rock breaking efficiency.Rock-boring organisms exist in nature,which achieve drilling and/or tunnelling in rocks through a tribochemical interaction.This phenomenon is called bioerosion and the organisms are natural‘TBMs’to some degree.In this study,the interaction between TBM cutters and rock is presented,and current measures to improve cutter wear and rock breaking efficiency and their limitations are reported.Then,the connotation,mechanism and typical cases of bioerosion are presented.Finally,inspired by bioerosion,a new chemically assisted rock breaking technology is proposed for TBMs.

Effects of Bacillus subtilis on hepatic lipid metabolism and oxidative shess response in grass carp(Ctenopharyngodon idellus)fed a high-fat diet

Bacillus subtilis is widely used in aquaculture as a probiotic.However,few studies have been conducted to examine the effect of B.subtilis on liver lipid metabolism.A total of 135 healthy grass carp(50.24±1.38 g)were randomly divided into three groups:control(Con),high-fat diet(HF),and high-fat diet+B.subtilis(HF4-B.subtilis),and fed for 8 weeks.The results showed that compared with the HF group,the weight gain rate(WGR)significantly increased(Pc0.05)and the hepatic lipid content,serum low-density lipoprotein cholesterol(LDL-C),and aspartate aminotransferase(AST)decreased in the group supplemented with B.subtilis(P<0.05).Moreover,the hepatic mRNA expression of fatty acid synthase(FAS)was significantly down-regulated and the carnitine palmitoyl transferases(CPTlala)were up-regulated in the HF+B.subtilis group compared to the HF group(P<0.05),respectively.Additionally,in the HF+B.subtilis group,glutathione(GSH)significantly increased(Pv 0.()5),while hydrogen peroxide(H2O2)and malondialdehyde(MDA)contents significantly decreased compared to the HF group(P v0.05).B.subtilis may reduce the hepatic lipid content by inhibiting its synthesis and promoting p-oxidation of fatty acids.B.subtilis may also alleviate dyslipidaemia and prevent oxidative damage in the liver caused by the high-fat diet of grass carp.Hence,dietary supplementation with B.subtilis shows promise as a therapeutic or preventive tool against fatty liver disease.

Bystander resuscitation of a near-drowning child in a rural south China township

We report resuscitation of a near-drowning child by a bystander in a rural south China township.Resuscitation was performed on a 6-year-old,otherwise healthy boy who was witnessed drowning in a river,with submersion for approximately 12 min.Following several resuscitation attempts,spontaneous breathing was established at the scene and the boy was transferred to a nearby hospital.He developed pneumonia but recovered completely on the ward and was discharged without any neurologic disabilities.This case shows that early bystander resuscitation is an important factor for survival after submersion.The search for an ideal approach to resuscitation must continue,and all members of society must work together towards this goal.