项目简介

计算机模拟已逐步成为继实验、形式理论之后发展起来的能够创造、发现新的科学现象和科学概念的重要方法,尤其是对于材料科学与工程领域中的模拟计算,其基石是建立在量子力学、经典力学和统计力学之上,通过建立适当的数据模型,利用数学和严谨的逻辑演绎而得到物质的形式和变化方式,因此对于理解、发现新材料背后的化学现象和物理本质以及设计新材料等方面发挥着重要的作用。 建设目标: 本平台提供了材料科学方向的分子模拟服务,致力于打造一个新材料的开发、设计与利用的多尺度模拟平台,解决金属材料、无机非金属材料、有机高分子材料、先进复合材料等材料,在不同尺度下(纳观、微观、介观以及宏观)的振动性质、磁学性质、电学性质、光学性质、力学性质以及热力学性质的模拟和预测。

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发布时间: 04/21/2015 18:00
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RT。大家可去看看这篇文献:Physics Letters B 694 (2011) 327–345。作者列表几页纸。
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【支持】 什么是分而治之方法? 正常
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发布时间: 04/21/2015 17:53
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如题,推荐一篇参考文献: Weitao Yang,Direct Calculation of Electron Density in Density-Functional Theory,PHYSICAL REVIEW LETTERS,66,1438(1991)
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发布时间: 04/21/2015 17:22
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vpn登录脚本如下: #!/bin/bash vpnc --gateway 61.144.43.67 --id linux passwd1 --username ipsec_yxyfz passwd2 然后使用crontab命令将上面脚本进行定时执行(每隔25分钟执行一次脚本): */25 * * * * /root/script/vpn_connect.sh
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发帖时间:04/21/2015 17:14
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The rapid increase in computer processing power and the availability of large-scale supercomputers has placed simulation at the forefront of the search for new materials. Building on our understanding of the chemical bond, advances in synthetic chemistry, and large-scale computation, materials design has now become a reality. Recently, combining the latest scientific achievements[1], Nature Chemistry proposed a route to the systematic discovery of new functional materials[2], i.e., prediction of functionality followed by laboratory synthesis and characterization. Materials chemists are spoiled for choice. Realistic estimates place the total number of possible materials as a googol (10E100), which is more than the number of atoms in the known universe (see discussions at http://hackingmaterials.com ). Therefore, the search for new materials thus requires navigating a multidimensional landscape of bewildering complexity. Even the most extensive high-throughput experimental or computational set-up will not succeed in screening all possibilities given realistic time and funding constraints. The motivation, however, is strong. Every advance in technology requires or would benefit from new components. This time the objective is to reduce cost, increase performance or replace rare elements with more sustainable earth-abundant alternatives. A key question is how to identify the specific arrangement of elements that produce the properties of interest as efficiently as possible? As they report in Nature Chemistry, Kenneth Poeppelmeier, Alex Zunger and co-workers have now tackled this issue using first-principles thermodynamics, and followed up their predictions with experimental validation.[1] Using quantum mechanical techniques, quantitative information on the structure and properties of a material can be provided at relatively modest computational and economic cost. For discovery of new materials, however, the most pragmatic approach is to introduce simulation constraints, e.g., fixing the chemical composition or the crystal structure. In the work of Poeppelmeier, Zunger and co-workers, a valiant route was taken to overcome these constraints. They chose to fix the valence state of their target compounds to satisfy the 18-electron rule, and screen both the chemical composition and crystal structure. To search for new materials, a rigorous multi-step selection process was implemented in the framework of DFT using the VASP (Fig. 1 shows one such process): Firstly, a crystal structure search was carried out to ensure a global minimum configuration was identified, and the vibrational spectrum of each candidate material was investigated to confirm its dynamic stability; secondly, thermodynamic calculations were performed to ensure stability with respect to each competing phase. As an example, they screened all possibilities from 483 chemically plausible ternary compounds with 18 valence electrons, and screened 54 candidate structures expected to steadily exist from 400 unreported compounds. In the end they successfully synthesized 15 of the 54 new materials. One of the roles of materials prediction in this study is to reduce the possible phase space and direct synthetic efforts to the most realistic and important targets. The simulations also provide valuable information to expedite the characterization of the novel compounds, ranging from predicted crystal structure parameters to vibrational and electronic spectral signatures. Although in the past materials modelling has been largely responsive to experiment, the predictive power of modern simulation techniques is becoming increasingly apparent. Therefore, the report believed that it is an exciting time for materials chemistry due to developing of computer simulation, especially supercomputing. The ability to synthesize materials of increasing complexity continues to astound. Even fundamental thermodynamic limits can be overcome, as metastable structures and kinetically stable compositions are accessible through non-equilibrium growth techniques. The challenge now is not simply to make new compounds, but to enable new functionality. The combination of theory and simulation has adopted a new role in the field, as a quantitative tool that can direct and inform experimental synthesis and characterization. When the integrated process—prediction of functionality in unreported compounds followed by laboratory synthesis and characterization—is used appropriately, it can help to navigate the immense structural and compositional landscape at a fraction of the time and cost of an empirical search. [1] Romain Gautier, Xiuwen Zhang, Linhua Hu, Liping Yu,Yuyuan Lin, Tor O. L. Sunde, Danbee Chon, Kenneth R. Poeppelmeier and Alex Zunger, Nature Chemistry 7, 308–316 (2015). [2] Aron Walsh, Nature Chemistry 7, 274 (2015).
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发帖时间:04/21/2015 17:13
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In Nature’s latest issue on March 5th, 2015, a new progress of the control mechanism of nano-materials movement has been reported in the “News & Views” column. High evaluation was paid to material computational simulation for the control mechanism. Being able to control the motion of nanomaterials would be extremely useful for processes that require the delivery of nanoscale molecules, and for the functioning of nanodevices such as energy conversion systems. With specific applications in mind, several techniques for moving various nanostructures have been proposed, yet all have suffered from various problems. Firstly, the nanostructures do not move spontaneously for these techniques. Furthermore, all these techniques can potentially damage the materials, which would reduce the repeatability of each process. These difficulties should be overcome, because viable nanotechnology must be reliable, reusable and cost-effective. Noticing the work done by Tienchong Chang et al. on Physical Review Letters [Phys. Rev. Lett. 114, 015504 (2015)], Nature wrote an article Nanoscale locomotion without fuel [Nature 519, 37 (2015), http://www.nature.com/nature/journal/v519/n7541/full/519037a.html] to give an introduction and assessment on their work. In their work, Chang et al. set up a series of virtual experiments using computer simulations as implemented in a classic molecular dynamics code LAMMPS. Computer simulations have revealed a mechanism by which nanostructures of the material graphene can be driven in one direction by controlling the stiffness of the underlying substrate, introducing a new way of moving nanoscale materials that does not need an external power source to drive it. The report believed that Chang and colleagues’ findings could have great potential in nanodevices, since the observed motion is conveniently unidirectional and the underlying forces fall within a useful and technologically accessible range. In the present report, the material computational simulation, including molecular dynamics, has also been rated high for two reasons: (1) this approach offers some advantages over real-world experiments: one can be sure that the materials are free of defects and impurities, and that they are electrically, thermally and chemically isolated, which is particularly important when seeking intrinsic phenomena; (2) it allows animations of modelled processes to be made. In the present case, the overall motion is dramatically displayed in an animation.
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发帖时间:04/21/2015 17:09
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伴随着当代计算机处理能力的日渐增强,尤其是大尺度超级计算机易用性的逐步提升,计算模拟已位居新型材料搜寻的前沿阵地。建立在大尺度超级计算、化学键机理及先进合成化学基础上的材料设计已不再是梦。近日,《自然.化学》结合最新的科学成果[1],提出了一条实现新型功能化材料探索的系统化路线[2],即计算预测化合物功能性——实验合成及表征。 材料化学的研究往往有眼花缭乱之感。据较为真实的估算,所有可能的化合物种类的总量(10E100)甚至多于已知宇宙中的原子数量(见http://hackingmaterials.com )。因此新型材料的探索无异于在充满复杂性的多维山脉里逡巡,即使最广泛、最强大的实验和高通量计算也不可能在有限的时间和资金下取得成功。然而,新型材料的探索意愿是强烈的;如同以往每次技术进步必有巨大价值诱惑驱使一样,这次的驱动力是减耗、提高材料表现及以地球富有元素取代稀有元素材料的可持续道路。解决问题的关键在于如何尽可能有效地识别出能产生让我们感兴趣性质的元素排列模式。Kenneth Poeppelmeier等在《自然.化学》里展现了他们的应对之道[1],即先以第一性原理热动力学计算作出预测,再以实验确证。 量子力学软件能以较为适当经济成本提供一种材料结构与物性的定量信息,但应用于搜索新型材料时,从实用主义出发大多数时候都要引入一定的模拟限制,例如固定材料的化学组分或晶体结构。针对这点,Poeppelmeier等在他们的工作中采取了一个大胆的尝试。他们选择了固定目标化合物的价态以满足18-电子规则,并同时从化学组分及晶体结构两方面进行材料筛选。为发现新型材料,他们利用VASP执行了一个严格的多步选择过程(见图1):先是搜索晶体结构以识别能量极小构型,并分析每种候选材料的振动谱以确认其动力学稳定性;然后进行热力学计算以确保其相对于其它任一竞争相的稳定性。作为例子,他们对483种具有18个价电子的化学上“看似可行”的三元化合物进行筛选,并从400种未曾报道过的化合物中筛选出54种有望稳定存在的候选结构;最后,他们成功制得了这54种材料中的15种。 上述工作中计算预测的一大作用是降低了成本,使研究者将合成新材料的精力花费在更真实更重要的目标化合物上。同时,模拟也提供了材料从晶体结构参数到振动、电子谱特征等方面的有价值信息,极大加速了新型材料的表征工作。当代先进的计算机建模和计算技术已摆脱了对实验结果的被动式响应,其对新现象新材料的预见性已愈发明显突出。 因此,文章认为由于计算机模拟尤其是超级计算的发展,材料化学迎来了激动人心的时刻。技术进步使得我们能合成越来越复杂的材料,甚至热力学极限也能被克服,如通过非平衡生长可以得到亚稳态结构和动力学稳定的化合物。而今,材料科学的挑战并非简单的制备新化合物,而是如何使其具备我们所期许的新功能。理论及计算机模拟相结合在这方面承担了新的角色,其作为定量工具能够直接指导新材料的实验合成及表征。正确地运用模拟——实验模式,将有助于在有限时间和开销下于浩瀚的结构和化合物大洋中搜索新材料。 [1] Romain Gautier, Xiuwen Zhang, Linhua Hu, Liping Yu,Yuyuan Lin, Tor O. L. Sunde, Danbee Chon, Kenneth R. Poeppelmeier and Alex Zunger, Nature Chemistry 7, 308–316 (2015). [2] Aron Walsh, Nature Chemistry 7, 274 (2015).
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发帖时间:04/21/2015 17:07
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2015年3月5日,《自然》杂志在其最新一期的“新闻&视点”栏目中,介绍了纳米材料运动控制理论的新进展,并对材料计算模拟在其中的贡献予以高度评价。 在纳米尺度分子传输及纳米器件功能化的相关过程中,纳米材料的运动控制尤为关键。出于应用需要,人们已提出过多种纳米结构搬运方案,但均遭遇各类困难。这些方案中,纳米结构并不能自发迁移,且材料有受损的潜在风险。这些都大大降低了运动过程的可再现性,并不符合操作的可靠性及经济效益指标。 《自然》注意到了Tienchong Chang等人发表在《物理评论快报》上的工作[Phys. Rev. Lett. 114, 015504 (2015)],撰写了题为《零燃料的纳米尺度运动》的文章[Nature 519, 37 (2015), http://www.nature.com/nature/journal/v519/n7541/full/519037a.html],对其工作进行了介绍及评价。该工作中,Tienchong Chang等应用分子动力学软件LAMMPS设计了一系列计算模拟虚拟实验,通过操纵材料下方衬底的刚度,实现了石墨烯纳米结构在特定方向的自发移动,呈现了一个无需外部干预实现的纳米尺度定向运动新机制。文章认为此发现对纳米器件的研发意义非凡,因为它使纳米材料的定向移动操作变得便利,同时其预言的参数也处于生产及实验可取得的合理范围内。 文章更高度评价了包括分子动力学在内的材料计算模拟手段。文章认为,计算模拟具有真实实验无法比拟的优势,它能保证研究对象是零缺陷和零杂质的纯净材料,且在电、热和化学上孤立于环境,确保了实验本质现象的准确性不受干扰。文章指出计算模拟的另一优点是使得建模过程及结果生动直观;在此模拟中,整个材料的运动过程以视频的形式清晰地展现在读者眼前,为刚度控制运动机制提供了直接的证据。
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发帖时间:04/21/2015 16:57
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本平台通过提供材料科学与工程方向的云超算模拟服务,致力于打造一个新型功能化材料研发与设计的多尺度模拟平台,模拟和预测跨尺度(微观、介观、宏观)材料的力、热、电磁及光学性质,为业界提供标准的材料应用开发一体化流程。以量子力学、统计力学与经典力学为理论基石的材料科学云超算模拟既可帮助用户建立材料模型并给出模型参数,又可直接与实验比对、指导相关应用性研究,从而实现用户新型材料探索全生命周期的优化设计。结合天河二号强大的计算资源,本平台上的云超算服务有助于改变传统计算模拟对实验结果的被动式响应局面,在新材料新现象研究上凸显出愈发卓越的预见性。 本平台目前已部署了ABINIT、GAMESS、Quantum ESPRESSO、Wannier90、LAMMPS、MEEP、MPB、OpenFOAM等模拟软件,支持不同尺度的材料进行高性能计算。本平台已支撑了量子自旋系统、化学催化机理研究及微纳器件设计等前沿项目的高仿真模拟计算。
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