在当今数字化时代,海量数据的生成和积累呈现出爆炸式增长的趋势,因此对存储容量的需求急速上升.传统磁记录磁盘CMR因其高容量和低成本而被视为解决海量数据存储的首选.然而,由于超顺磁效应的制约,CMR(Conventional Magnetic Recording...在当今数字化时代,海量数据的生成和积累呈现出爆炸式增长的趋势,因此对存储容量的需求急速上升.传统磁记录磁盘CMR因其高容量和低成本而被视为解决海量数据存储的首选.然而,由于超顺磁效应的制约,CMR(Conventional Magnetic Recording)磁盘面密度的提升已触及极限.为了突破这一限制,叠瓦式磁记录技术SMR(Shingled Magnetic Recording)应运而生.基于传统硬盘架构,该技术以重叠磁道的方式,显著提升了磁盘面密度.但SMR磁盘在处理随机写时,会产生不可预测的写放大效应,从而严重影响I/O性能.为解决这一问题,业界随即提出了交错式磁记录技术IMR(Interlaced Magnetic Recording),利用优化的磁道布局和热辅助磁记录技术,有效实现了存储容量与性能的平衡.本文首先详细介绍了SMR和IMR的技术原理和磁盘类型,并量化分析了影响设备I/O性能的关键问题.然后,重点介绍了设备级优化方案,分析并总结了不同策略的优缺点与优化目标.接着,概述了面向设备的系统级和应用级设计方案,如文件系统、独立磁盘阵列技术和数据库等.最后讨论了在未来优化SMR磁盘和IMR磁盘性能可能的研究方向.展开更多
热辅助磁记录(Heat Assisted Magnetic Recording)技术是通过激光加热磁存储介质以减小介质矫顽力,从而使得磁头易于对存储介质进行磁化的一种技术。因超顺磁效应问题,为了达到超高密度存储的目标则需大幅提高介质的矫顽力,由此显著增...热辅助磁记录(Heat Assisted Magnetic Recording)技术是通过激光加热磁存储介质以减小介质矫顽力,从而使得磁头易于对存储介质进行磁化的一种技术。因超顺磁效应问题,为了达到超高密度存储的目标则需大幅提高介质的矫顽力,由此显著增加了磁头写入的困难性。采用HAMR技术可有效提高磁头在微场强条件下的高密度信息写入能力,从而被认为是可间接应对超顺磁效应的下一代超高密度存储技术途径之一。本文分别就HAMR技术提出的背景、研究现状和发展前景进行了系统的介绍,并且讨论了与之相关的几个关键问题。采用HAMR技术,可望使磁盘存储的面密度提升至5Tb/in^2,而若将其与其他的技术(如BPM,Bit-Patterned Media技术)相结合,则可使面密度大幅度提高到300Tb/in^2或更高。展开更多
近年来硬盘的储存容量一直以缓慢的速度增长。新的垂直存储技术虽然成功突破了传统磁存储技术所遇到的瓶颈,成功将民用硬盘存储容量提升至TB级别,但是面对一张光盘就达数十GB的高清时代,存储容量的压力依然很大。那么如何进一步提升磁...近年来硬盘的储存容量一直以缓慢的速度增长。新的垂直存储技术虽然成功突破了传统磁存储技术所遇到的瓶颈,成功将民用硬盘存储容量提升至TB级别,但是面对一张光盘就达数十GB的高清时代,存储容量的压力依然很大。那么如何进一步提升磁盘存储密度?PMM(Patterned Magnetic Media,规则磁媒体)技术就是开启新存储时代的金钥。展开更多
The potential applications of superparamagnetic iron oxide nanoparticles （SPIONs） in several nanomedical fields have attract- ed intense interest based on the cell-nano interaction. However, the mechanisms underlyin...The potential applications of superparamagnetic iron oxide nanoparticles （SPIONs） in several nanomedical fields have attract- ed intense interest based on the cell-nano interaction. However, the mechanisms underlying cell uptake, the intracellular trail, final fate and the biological effects of SPIONs have not yet been clearly elucidated. Here, we showed that multiple endocytic pathways were involved in the internalization process of SPIONs in the RAW264.7 macrophage. The internalized SPIONs were biocompatible and used three different metabolic pathways： The SPIONs were distributed to daughter cells during mito- sis; they were degraded in the lysosome and free iron was released into the intracellular iron metabolic pool; and, the intact SPIONs were potentially exocytosed out of the cells. The internalized SPIONs did not induce cell damage hut affected iron metabolism, inducing the upregulation of ferritin light chain at both the mRNA and protein levels and ferroportin 1 at the mRNA level. These results may contribute to the development of nanobiology and to the safe use of SPIONs in medicine when administered as a contrast medium or a drug delivery tool.展开更多
Because of the toxicity of Gd(Ⅲ)complexes and the poor T1 magnetic resonance imaging(MRI)contrast of superparamagnetic iron oxide,the development of new stable,non-toxic,and efficient contrast agents is desirable.Her...Because of the toxicity of Gd(Ⅲ)complexes and the poor T1 magnetic resonance imaging(MRI)contrast of superparamagnetic iron oxide,the development of new stable,non-toxic,and efficient contrast agents is desirable.Herein,tannic acid(TA),a large natural polyphenol,and bovine serum albumin(BSA)were used to construct non-toxic Fe(Ⅲ)complexes with increased relaxivity based on a strategy slowing the molecular spin.Compared with the commercial T1 contrast agent Magnevist■,TA-Fe@BSA not only exhibits comparable T1 MRI contrast enhancement under 0.5,1 and 7 T magnetic fields both in vitro and in vivo,but also has better stability and biocompatibility.Moreover,TA-Fe@BSA with near-infrared(NIR)absorption demonstrates efficient tumor ablation via photothermal effects.These results demonstrate their strong potential as an alternative T1 MRI contrast agent and tumor theranostics agent in clinical settings.展开更多
文摘在当今数字化时代,海量数据的生成和积累呈现出爆炸式增长的趋势,因此对存储容量的需求急速上升.传统磁记录磁盘CMR因其高容量和低成本而被视为解决海量数据存储的首选.然而,由于超顺磁效应的制约,CMR(Conventional Magnetic Recording)磁盘面密度的提升已触及极限.为了突破这一限制,叠瓦式磁记录技术SMR(Shingled Magnetic Recording)应运而生.基于传统硬盘架构,该技术以重叠磁道的方式,显著提升了磁盘面密度.但SMR磁盘在处理随机写时,会产生不可预测的写放大效应,从而严重影响I/O性能.为解决这一问题,业界随即提出了交错式磁记录技术IMR(Interlaced Magnetic Recording),利用优化的磁道布局和热辅助磁记录技术,有效实现了存储容量与性能的平衡.本文首先详细介绍了SMR和IMR的技术原理和磁盘类型,并量化分析了影响设备I/O性能的关键问题.然后,重点介绍了设备级优化方案,分析并总结了不同策略的优缺点与优化目标.接着,概述了面向设备的系统级和应用级设计方案,如文件系统、独立磁盘阵列技术和数据库等.最后讨论了在未来优化SMR磁盘和IMR磁盘性能可能的研究方向.
文摘热辅助磁记录(Heat Assisted Magnetic Recording)技术是通过激光加热磁存储介质以减小介质矫顽力,从而使得磁头易于对存储介质进行磁化的一种技术。因超顺磁效应问题,为了达到超高密度存储的目标则需大幅提高介质的矫顽力,由此显著增加了磁头写入的困难性。采用HAMR技术可有效提高磁头在微场强条件下的高密度信息写入能力,从而被认为是可间接应对超顺磁效应的下一代超高密度存储技术途径之一。本文分别就HAMR技术提出的背景、研究现状和发展前景进行了系统的介绍,并且讨论了与之相关的几个关键问题。采用HAMR技术,可望使磁盘存储的面密度提升至5Tb/in^2,而若将其与其他的技术(如BPM,Bit-Patterned Media技术)相结合,则可使面密度大幅度提高到300Tb/in^2或更高。
文摘近年来硬盘的储存容量一直以缓慢的速度增长。新的垂直存储技术虽然成功突破了传统磁存储技术所遇到的瓶颈,成功将民用硬盘存储容量提升至TB级别,但是面对一张光盘就达数十GB的高清时代,存储容量的压力依然很大。那么如何进一步提升磁盘存储密度?PMM(Patterned Magnetic Media,规则磁媒体)技术就是开启新存储时代的金钥。
基金supported by the National Basic Research Program of China,Ministry of Science and Technology of China (Grant Nos. 2006CB933202 and 2011CB933504) the National High Technology Research and Development Program of China (Grant No. 2008AA02Z425)a grant from the National Natural Science Foundation of China (Grant No.81071072)
文摘The potential applications of superparamagnetic iron oxide nanoparticles （SPIONs） in several nanomedical fields have attract- ed intense interest based on the cell-nano interaction. However, the mechanisms underlying cell uptake, the intracellular trail, final fate and the biological effects of SPIONs have not yet been clearly elucidated. Here, we showed that multiple endocytic pathways were involved in the internalization process of SPIONs in the RAW264.7 macrophage. The internalized SPIONs were biocompatible and used three different metabolic pathways： The SPIONs were distributed to daughter cells during mito- sis; they were degraded in the lysosome and free iron was released into the intracellular iron metabolic pool; and, the intact SPIONs were potentially exocytosed out of the cells. The internalized SPIONs did not induce cell damage hut affected iron metabolism, inducing the upregulation of ferritin light chain at both the mRNA and protein levels and ferroportin 1 at the mRNA level. These results may contribute to the development of nanobiology and to the safe use of SPIONs in medicine when administered as a contrast medium or a drug delivery tool.
基金the National Natural Science Foundation of China(91959105 and 21671135)Shanghai Sailing Program(19YF1436200)+2 种基金Shanghai Rising-Star Program(17QA1402600)Shanghai Talent Development Fund(2018082)Shanghai Engineering Research Center of Green Energy Chemical Engineering(18DZ2254200)。
文摘Because of the toxicity of Gd(Ⅲ)complexes and the poor T1 magnetic resonance imaging(MRI)contrast of superparamagnetic iron oxide,the development of new stable,non-toxic,and efficient contrast agents is desirable.Herein,tannic acid(TA),a large natural polyphenol,and bovine serum albumin(BSA)were used to construct non-toxic Fe(Ⅲ)complexes with increased relaxivity based on a strategy slowing the molecular spin.Compared with the commercial T1 contrast agent Magnevist■,TA-Fe@BSA not only exhibits comparable T1 MRI contrast enhancement under 0.5,1 and 7 T magnetic fields both in vitro and in vivo,but also has better stability and biocompatibility.Moreover,TA-Fe@BSA with near-infrared(NIR)absorption demonstrates efficient tumor ablation via photothermal effects.These results demonstrate their strong potential as an alternative T1 MRI contrast agent and tumor theranostics agent in clinical settings.
