General way to define tunneling time

With the development of attosecond science, tunneling time can now be measured experimentally with the attoclock technique. However, there are many different theoretical definitions of tunneling time and no consensus has been achieved.Here, we bridge the relationship between different definitions of tunneling time based on a quantum travel time in onedimensional rectangular barrier tunneling problem. We find that the real quantum travel time t_(Re) is equal to the Bohmian time t_(Bohmian), which is related to the resonance lifetime of a bound state. The total quantum travel time τt can perfectly retrieve the transversal time t_x and the Büttiker–Landauer time τ_(BL) in two opposite limits, regardless of the particle energy.

气固摆动流化床的气泡运动特性

气泡现象是气固流态化的基本现象之一,了解摆动床气泡特性对推动流态化技术的海上应用具有重要意义。采用二维床及B类玻璃球颗粒的摆动床,通过对图像进行分析,研究了气泡在摆动过程中不同时间段的上升特点;提出了“热区图”方法,发现在较高表观气速时存在气泡聚集方向转换“滞后”于床体姿态转换的现象,原因为颗粒所受科氏力使其向摆动反方向聚集,抑制气泡聚集方向的转换;对IOP曲线的分析结果表明,气泡在床内分布位置、气泡平均尺寸及气泡生成与破裂频率等时均特征介于倾斜床与直立床之间;操作气速增加会使摆动床内气泡平均尺寸及气泡生成破裂频率都增加;摆动幅值增加只会使气泡生成与破裂频率明显增加;摆动周期对两者的影响均不明显。

CD205-TLR9-IL-12 axis contributes to CpG-induced oversensitive liver injury in HBsAg transgenic mice by promoting the interaction of NKT cells with Kupffer cells

Gut-derived bacterial products contribute to liver inflammation and injury during chronic hepatitis B virus infection;however,the underlying mechanisms remain obscure.In this study,hepatitis B surface antigen transgenic(HBs-Tg)mice and their wild-type(WT)control C57BL/6 mice were injected with CpG-oligodeoxynucleotides(ODNs)to mimic the translocation of gut microbial products into the systemic circulation.We found that,compared with the WT mice,the HBs-Tg mice were oversensitive to CpG-ODN-induced liver injury,which was dependent on natural killer T(NKT)cells.CpG-ODN injection enhanced the expression of Fas ligand(FasL)on NKT cells.In addition,hepatocytes from the HBs-Tg mice expressed higher levels of Fas than did those from the WT mice,which was further augmented by CpG-ODN.Interaction of Fas and FasL was involved in the cytotoxicity of NKT cells against hepatocytes in the HBs-Tg mice.Moreover,Kupffer cells in the HBs-Tg mice expressed higher levels of CD205 and produced greater amounts of interleukin(IL)-12 than did those in the WT mice.Finally,the depletion of Kupffer cells,neutralization of IL-12 or specific silencing of CD205 on Kupffer cells significantly inhibited CpG-ODN-induced liver injury and NKT activation in the HBs-Tg mice.Our data suggest that CD205-expressing Kupffer cells respond to CpG-ODNs and subsequently release IL-12 to promote NKT cell activation.Activated NKT cells induce liver damage through the Fas signaling pathway in HBs-Tg mice.

Recent advances for the production of hydrocarbon biofuel via deoxygenation progress

The current world energy crisis and increasing environmental concerns over global climate change from combusting fossil fuel are driving researchers into a new route to produce fuels via sustainable resource to meet the demands of human. In recent years, deoxygenation as an alternative method has been applied in the production of hydrocarbon fuels, particularly via the deoxygenation of fatty acids and triglycerides from seed oils and fats, producing hydrocarbon fuels entirely fungible with fossil fuels. The deoxygenation of biobased feedstock to fuel-like hydrocarbons is critically reviewed in this article. The review mainly discusses the use of feedstock, innovation of catalysts, and the reaction mechanism involved in the production of hydrocarbon fuels via deoxygenation progress.

HBsAg-specific CD8^(+)T cells as an indispensable trigger to induce murine hepatocellular carcinoma

Hepatitis B virus(HBV)-associated hepatocellular carcinoma(HCC)is mediated by an inappropriate attack by HBV-specific T cells in patients.However,this immunopathogenic process has not been clarified because of the lack of a suitable animal model.Here,we used immunocompetent Fah^(-/-)mice as the recipients in the adoptive transfer of HBsAg^(+)hepatocytes from HBs-Tg mice to replace the recipient hepatocytes(HBs-HepR).HBs-HepR mice exhitited persistent HBsAg expression with chronic hepatitis and eventually developed HCC with a prevalence of 100%.HBsAg-specific CD8^(+)T cells were generated and specifically and continuously induced hepatocyte apoptosis with progressive chronic inflammation,and the depletion of CD8^(+)T cells or their deficiency prevented HCC,which could then be reproduced by the transfer of HBsAg-specific CD8^(+)T cells.In summary,our results demonstrated that CD8^(+)T cells plays a critical role in HBsAg-driven inflammtion and HCC tumorigenesis.

In-situ Observation of Tensile Fracture in A357 Casting Alloys

The mechanism of damage evolution and fracture in A357 casting alloys was investigated by in-situ scanning electron microscopy （SEM） tensile testing. Different microstructures of A357 casting alloys were produced by eutectic Si modification and T6 heat treatment. It is shown that microcracks in these alloys are predominantly formed in eutectic Si particles. Large and elongated eutectic Si particles in unmodified alloy show the greater tendency to cracking, whereas cracking of small and round eutectic Si particles in Sr modified and T6 heat treated alloys is relatively lag. The crack mainly propagates along the broken eutectic Si particles in unmodified and Sr modified alloys or along the deepened shear bands in T6 heat treated alloy with accumulating the applied strain. The results were discussed in terms of Weibull statistics and the fracture models were established.

Erratum to: Recent advances for the production of hydrocarbon biofuel via deoxygenation progress

1 Erratum to:Sci.Bull.(2015)60(24):2096–2106DOI 10.1007/s11434-015-0971-0In the original publication of this paper,the pathways proposed for the deoxygenation of a fatty acid ester into hydrocarbons in Scheme 2 was incorrect.The corrected pathways appear in this erratum(Scheme 2).