HSP: A solution against heap sprays

Heap sprays are a new buffer overflow attack (BOA) form that can significantly increase the successful chance of a BOA even though the attacked process is protected by a lot of state-of-the-art anti-BOA mechanisms, such as ASLR, non-executable stack/DEP, signature-based IDSes, and type-safe languages. In this paper, we propose a glibc-and-ASLR-based solution to heap sprays—Heap Spray Protector (HSP). HSP controls the number and location of int 80 instructions in a process and hides the whereabouts of the only legal int 80 instruction; hence, HSP makes it difficult for attackers to issue a system call, let alone a heap spray attack. Moreover HSP can help ASLR defend against memory information leaking attacks. Furthermore, because HSP only modifies the glibc library and the kernel, it does not need to modify any source code or executable file. Finally, HSP allows attackers to execute as much code as possible before an attack can really create some damage; therefore, it enables the attacked hosts to collect more information about attackers which may be useful to block future attacks. Experimental results show HSP implemented on a Linux platform can effectively defend a system against heap sprays with less than 4.56% performance overhead.     

有损伤框架结构中的波动分析

基于回传射线矩阵法，研究了有损伤框架结构在水平方波脉冲作用下脉冲作用点的速度波，结构的局部损伤用减小受损单元的横截面面积来模拟。结果表明：改变脉冲作用点位置，通过脉冲作用点横向速度波首波波幅的变化可以确定受损单元的起始位置；当脉冲作用点在受损单元的起始位置时，脉冲作用点横向速度波首波波幅变化越大，损伤越大，脉冲作用点横向速度波的第一个波谷到达时间越晚，损伤单元越长。     

在消费类便携设备中实现精确的运动跟踪

以智能手机为主,包括智能腕表、健身追踪器和可听戴设备等在内的各类便携式联网电子设备,彻底改变了我们的生活.这些设备在数据采集中融入了处理功能和无线联网技术.     

Lattice and Surface Engineering of Ruthenium Nanostructures for Enhanced Hydrogen Oxidation Catalysis

Ru has recently been considered as a promising alternative of Pt toward hydrogen oxidation reaction (HOR) due to its lower price and similar hydrogen binding energy (HBE) in comparison to Pt. Nevertheless, the catalytic performance of Ru toward HOR is far from the satisfaction of practical application. Herein, it is demonstrated that the modification of Ru multi-layered nanosheet (MLNS) with Ni can significantly promote the HOR performance. In particular, the HOR performance is strongly related to the Ni location on the surface or in the lattice of Ru MLNS. Experimental and theoretical investigations suggest that Ni in the lattice of Ru MLNS (lattice engineering) optimizes the HBE, while Ni species on the surface (surface engineering) decrease the free energy of water formation, as a result of the significantly enhanced HOR performance. The optimal catalyst, where Ni is located both on the surface and in the lattice, displays superior alkaline HOR performance to commercial Pt/C and Ru/C. The present study not only systematically reveals the significance of Ni modification on Ru toward HOR, but also promotes the fundamental researches on catalyst design for fuel cell reactions and beyond.     

A Derivative of ZnIn2S4 Nanosheet Supported Pd Boosts Selective CO2 Hydrogenation

CO₂ hydrogenation to value-added chemicals has been considered as a promising way to reduce CO₂ emission and alleviate energy crisis. However, the high-efficiency CO₂ hydrogenation process is driven by the current drawbacks of low activity and/or selectivity. Herein, it is demonstrated that 2D S-doped ZnInO_x, which evolves from the calcination of ZnIn₂S₄ nanosheets (ZIS NSs), can serve as a functional support for Pd nanoparticles (NPs) to promote the selective CO₂ hydrogenation to CH₃OH. Detailed investigations show that ZnIn₂S₄ will evolve into In₂O₃ and amorphous S-doped ZnO, on which Pd NPs are preferentially located due to the strong electrophilicity of S. Consequently, the strong interaction between Pd NPs and amorphous S-doped ZnO prevents Pd NPs from sintering and facilitates the selective CO₂ hydrogenation to produce CH₃OH. The optimal catalyst shows a CO₂ conversion of 12.7% with a CH₃OH selectivity of 87.4% at 280 °C. This study provides a facile route to regulate catalytic supports and controllably load active species, which may attract great research interests in the fields of heterogeneous catalysis.     

常温低温发酵对二次发酵辣椒酱品质的影响比较

目的 比较分析常温低温发酵对二次发酵辣椒酱品质的影响。方法 本研究测定了不同温度下二次发酵辣椒酱的总酸、氨基酸态氮、总糖、还原糖等指标，采用电子鼻技术对其风味轮廓进行了描述，并通过顶空固相微萃取-气相色谱-质谱法(headspace solid-phase microextraction-gas chromatography-mass spectrometry，HS-SPME-GC-MS)结合香气活度值对3个发酵时间节点的挥发性成分及主要风味物质进行了分析。结果 辣椒酱的总糖及还原糖含量随发酵时间呈下降趋势，且发酵温度越高，减少的速率越快；总酸含量随发酵时间呈上升趋势，但氨基酸态氮含量变化并不明显；不同温度下发酵辣椒酱风味成分种类存在一定的差异；通过HS-SPME-GC-MS共检出71种挥发性成分。其中乙烯基愈疮木酚(辛香、木香)、苯乙醛(风信子香)、水杨酸甲酯(甜香、薄荷香)、棕榈酸乙酯(奶油香)为不同发酵温度共有的呈香物质。二烯丙基二硫(蒜香)为低温发酵辣椒酱特有的呈香物质，芳樟醇(花香)、肉豆蔻酸甲酯(焦香风味)、油酸乙酯(奶油香)、γ-雪松烯(松木香)等为协调呈香物质。亚油酸乙酯(花果香)、癸酸乙酯(椰子香)、水杨酸甲酯(甜香、薄荷香)、棕榈酸乙酯(奶油香)、4-乙基苯酚(烟熏香)等为常温发酵辣椒酱的呈香物质。结论 常温发酵条件下风味物质的生成速度与增量远优于低温发酵，表明常温发酵优于低温发酵。本研究为盐胚辣椒的风味强化提供了新的思路，为今后辣椒酱及剁辣椒产品开发提供了技术支撑。