中国火井历史新证

半个世纪来,中国火井历史研究取得了丰硕成果,也因史料缺略和理解差异而产生了若干争议。新发现的５种火井史料揭示了１６－１８世纪火井开发和天然气煮盐的实况,证实了汉晋临邛火井到清代自流井气水田之间火井技术的演进过程。当时试图对这一自然奇观作出诠释的中外学者,未能摆脱中国和欧洲传统科学思想的束缚,因此也难以克服理论与实践背离的积弊。     

Genome-wide association analysis identifies three psoriasis susceptibility loci

We carried out a meta-analysis of two recent psoriasis genome-wide association studies with a combined discovery sample of 1,831 affected individuals (cases) and 2,546 controls. One hundred and two loci selected based on P value rankings were followed up in a three-stage replication study including 4,064 cases and 4,685 controls from Michigan, Toronto, Newfoundland and Germany. In the combined meta-analysis, we identified three new susceptibility loci, including one at NOS2 (rs4795067, combined P = 4 × 10?11), one at FBXL19 (rs10782001, combined P = 9 × 10?1?) and one near PSMA6-NFKBIA (rs12586317, combined P = 2 × 10??). All three loci were also associated with psoriatic arthritis (rs4795067, combined P = 1 × 10??; rs10782001, combined P = 4 × 10??; and rs12586317, combined P = 6 × 1??) and purely cutaneous psoriasis (rs4795067, combined P = 1 × 10??; rs10782001, combined P = 2 × 10??; and rs12586317, combined P = 1 × 10??). We also replicated a recently identified association signal near RNF114 (rs495337, combined P = 2 × 10??).     

双束电子束焊接温度场的数值模拟

结合数值模拟和实验,研究了双束电子束焊接过程的温度场.根据对电子束的能量分布的测试数据,考虑电子束焊接的小孔效应和电子的散射和反射,得到了电子束焊接过程真实的能量输入.将该能量输入通过有限元软件的子程序实现加载,得到双移动热源,同时考虑到焊接材料的非线性,得到有限元数值模型,进行了数值模拟,并在相同条件下进行了多组实验.数值模拟和实验表明: 焊缝特征和温度场都与2个热输入的比例有关, 2个温度场是相互影响的;在小热源的焊接路径上,会出现2个热循环峰值.     

Ecology: a niche for cyanobacteria containing chlorophyll d

The cyanobacterium known as Acaryochloris marina is a unique phototroph that uses chlorophyll d as its principal light-harvesting pigment instead of chlorophyll a, the form commonly found in plants, algae and other cyanobacteria; this means that it depends on far-red light for photosynthesis. Here we demonstrate photosynthetic activity in Acaryochloris-like phototrophs that live underneath minute coral-reef invertebrates (didemnid ascidians) in a shaded niche enriched in near-infrared light. This discovery clarifies how these cyanobacteria are able to thrive as free-living organisms in their natural habitat.     

中锰钢奥氏体逆相变的多相场模拟

Medium-Mn steels have attracted immense attention for automotive applications owing to their outstanding combination of high strength and superior ductility. This steel class is generally characterized by an ultrafine-grained duplex microstructure consisting of ferrite and a large amount of austenite. Such a unique microstructure is processed by intercritical annealing, where austenite reversion occurs in a fine martensitic matrix. In the present study, austenite reversion in a medium-Mn alloy was simulated by the multiphase-field approach using the commercial software MICRESS? coupled with the thermodynamic database TCFE8 and the kinetic database MOBFE2. In particular, a faceted anisotropy model was incorporated to replicate the lamellar morphology of reversed austenite. The simulated microstructural morphology and phase transformation kinetics (indicated by the amount of phase) concurred well with experimental observations by scanning electron microscopy and in situ synchrotron high-energy X-ray diffraction, respectively.