基于人工鱼群算法的随机结构AMD控制系统LQR权矩阵优化

针对随机结构在平稳随机激励下线性二次最优控制的权参数选取问题,提出了基于人工鱼群算法的随机结构AMD控制系统权矩阵优化设计方法。该方法以结构随机响应和控制力均方值的加权组合为目标函数,考虑了结构和外激励的随机性对于控制效果的影响。其优化结果不仅保证了控制器的控制效果,而且降低了控制效果对于随机参数的敏感性,增强了控制器的鲁棒性。最后结合数值算例,验证了所述方法的有效性和正确性。     

结构AMD系统的控制力特性

以76层Benchmark钢筋混凝土结构风振控制问题为背景,分析了AMD主动控制的控制力特性,并与结构层间主动控制进行方案比较。首先,在Benchmark问题标准解的基础上提出了基于非降阶模型的AMD控制方案以及结构层间主动控制方案,在两种方案使结构整体响应控制在相同量值的前提下,定量分析比较了各方案的控制效果和控制代价,得出AMD控制方案性价比高的结论。其次,定义了改进的表征主动控制力方向特征的能量指标体系,数值分析比较了各方案主动控制力的方向与能量特征。分析结果表明能量特征指标更好地揭示了结构层间主动控制力为阻尼力的实质。深入分析结果表明:AMD控制将作动器集中使用,以较小的控制力、较大的控制器行程,实现对结构振动的控制能量输入;然而结构层间主动控制方案是以分散于结构各层层间的主动控制作动器,以较大的控制力吨位、相对较小的行程(与层间剪切变形有关)实现对结构振动的阻尼耗能控制。     

Diversity of microbial community at acid mine drainages from Dachang metals-rich mine, China

Two acid mine drainage (AMD) samples TS and WK, which were from the Dachang metals-rich mine in Guangxi province, China, were studied using PCR-based cloning approach. A total of 44 operational taxonomic units (OTUs) were obtained from the two AMD samples. However, only three OTUs (GXDC-9, GXDC-19 and GXDC-50) detected in sample TS can also be observed in sample WK. Phylogenetic analysis revealed that the bacteria in the two samples fell into four putative divisions, which were Nitrospira, Alphaproteobacteria, Gamaproteobacteria, and Acidobacteria. Organisms of genuses Acidithiobacillus and Leptospirillum, which were in gamaproteobacteria class and Nitrospira family, were dominant in two samples, respectively. In sample TS, which was characterized by low pH, high sulfate, high iron, and high arsenide, two species (Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans) constituted 98.22% of the entire microbial community. Compared with sample TS, the microbial community in sample WK was more diversified according to the observation. Interestedly, the Legionella species, which was rarely observed in the low-pH environment, was detected in sample WK. This work helps us to further understand the diversity of microbial community living in extreme acid mine drainages with unique geochemistry and the tolerance capability of acidophiles to heavy metal.     

Growth of sulfate-reducing bacteria under acidic conditions in an upflow anaerobic bioreactor as a treatment system for acid mine drainage

The aim of this investigation was to develop a system for the remediation of acid mine drainage using sulphate-reducing bacteria. An upflow porous medium bioreactor was inoculated with sulphate-reducing bacteria (SRB) and operated under acidic conditions. The reactor was operated under continuous flow and was shown to be capable of sulfate reduction at pH 4.5, 4.0, 3.5 and 3.25 in a medium containing 16.1 mM sodium lactate. This contrasted previously published work which showed that, at pH 3.8, organic acid concentrations greater than 5 mM completely inhibited biological sulfate-reduction. At pH 3.25 the reactor removed 38.3% of influent sulfate and raised the pH of the medium to 5.82. The lactate carbon source was exhausted under these conditions. At pH 3.0, sulfide production was below detectable levels, and sulfate removal fell to 14.4%. However, viable SRB were recovered from the column after 21 days of operation at pH 3.0, indicating that SRB are capable of withstanding pH 3.0 for extended periods. From these results we can conclude that an SRB process would be a viable method of remediating AMD.     

The Aging Stress Response and Its Implication for AMD Pathogenesis

Aging induces several stress response pathways to counterbalance detrimental changes associated with this process. These pathways include nutrient signaling, proteostasis, mitochondrial quality control and DNA damage response. At the cellular level, these pathways are controlled by evolutionarily conserved signaling molecules, such as 5’AMP-activated protein kinase (AMPK), mechanistic target of rapamycin (mTOR), insulin/insulin-like growth factor 1 (IGF-1) and sirtuins, including SIRT1. Peroxisome proliferation-activated receptor coactivator 1 alpha (PGC-1α), encoded by the PPARGC1A gene, playing an important role in antioxidant defense and mitochondrial biogenesis, may interact with these molecules influencing lifespan and general fitness. Perturbation in the aging stress response may lead to aging-related disorders, including age-related macular degeneration (AMD), the main reason for vision loss in the elderly. This is supported by studies showing an important role of disturbances in mitochondrial metabolism, DDR and autophagy in AMD pathogenesis. In addition, disturbed expression of PGC-1α was shown to associate with AMD. Therefore, the aging stress response may be critical for AMD pathogenesis, and further studies are needed to precisely determine mechanisms underlying its role in AMD. These studies can include research on retinal cells produced from pluripotent stem cells obtained from AMD donors with the mutations, either native or engineered, in the critical genes for the aging stress response, including AMPK, IGF1, MTOR, SIRT1 and PPARGC1A.     

AMD Athlon X2 5000开核特性研究

AMD部分CPU可以开核是近来计算机硬件界的热门话题。文章以AMD Athlon X2 5000CPU为例,对AMDCPU开核特性进行研究。实测表明,AMD Athlon X2 5000开核后各项性能比开核前大幅提高,开四核效果明显。该研究结果对当前计算机用户选购和使用AMDCPU具有指导意义。     

Acidophilic bacterial community reflecting pollution level of sulphide mine impacted by acid mine drainage

To reveal the impact of mining on bacterial ecology around mining area, bacterial community and geochemical characteristics about Dabaoshan Mine (Guangdong Province, China) were studied. By amplified ribosomal DNA restriction analysis and phylogenetic analysis, it is found that mining pollution greatly impacts the bacterial ecology and makes the habitat type of polluted environments close to acid mine drainage (AMD) ecology. The polluted environment is acidified so greatly that neutrophil and alkaliphilic microbes are massively dead and decomposed. It provided organic matters that can make Acidiphilium sp. rapidly grow and become the most bacterial species in this niche. Furthermore, Acidithiobacillus ferrooxidans and Leptospirillum sp. are also present in this niche. The amount of Leptospirillum sp. is far more than that of Acidithiobacillus ferrooxidans, which indicates that the concentration of toxic ions is very high. The conclusions of biogeochemical analysis and microbiological monitor are identical. Moreover, because the growth of Acidithiobacillus ferrooxidans and Leptospirillum sp. depends on ferrous iron or inorganic redox sulfur compounds which can be supplied by continual AMD, their presence indicates that AMD still flows into the site. And the area is closer to the outfalls of AMD, their biomasses would be more. So the distinction of their biomasses among different areas can help us to find the effluent route of AMD. Foundation item: Project(50621063) supported by the Science Fund for Creative Research Groups of China; Project(2004CB619201) supported by the Major State Basic Research Development Program of China     

碳酸盐型硫化物尾矿酸化及其研究意义

碳酸盐型硫化物矿尾矿因富含碱性碳酸盐,其酸化（尾矿中所含的硫化物氧化并释放出酸性水）问题一直不为人们所重视。通过对桂北（及邻区）碳酸盐岩区金属硫化物矿山尾矿污染的调研后发现：碳酸盐型尾矿酸化具有遍在性;尾矿能否发生酸化不能仅根据尾矿中碱性碳酸盐的含量简单地进行判断。经初步分析表明,在尾矿酸化过程中,碳酸盐颗粒的表面所形成的次生矿物（高价铁氢氧化物及石膏等）包壳可降低尾矿中碳酸盐中和酸的有效性,此即为＂富含碱性碳酸盐的硫化物尾矿仍可发生酸化＂的原因之一。深入研究碳酸盐型尾矿酸化机制,对于完善硫化物尾矿AMD的成因理论和预测评价体系,以及指导碳酸盐岩地区金属硫化物矿山AMD污染的防治,具有理论和实际意义。     

Single- and multi-GPU computing on NVIDIA- and AMD-based server platforms for solidification modeling application

This work explores the performance of single- and multi-GPU computing on state-of-the-art NVIDIA- and AMD-based server-class hardware using various programming interfaces to accelerate a real-world scientific application for solidification modeling based on the phase-field method. The main computations of this memory-bound application correspond to 20 stencils computed across grid nodes. We investigate the application's scalability for two basic schemes of organizing computation: without and with hiding data transfers behind computation, combined with using either peer-to-peer inter-GPU data transfers through NVIDIA NVLink and AMD Infinity interconnects or communication over the PCIe and main memory. Among the studied programming interfaces is CUDA, HIP, and OpenMP Accelerator Model. While the first two are designed to write the codes for a specific hardware platform, OpenMP enables code portability between NVIDIA and AMD GPUs. The resulting performance is experimentally assessed on computing platforms containing NVIDIA V100 (up to 8 GPUs) and A100 (one GPU), as well as AMD MI210 (one device) and MI250 (up to 8 logical GPUs).