基于USB 3.0的NAND FLASH数据存储设计

由于目前采用的串口和USB 2.0检测坏块、实现数据读取的方法存在数据读取慢以及数据稳定性低的问题,而在高速大容量存储装置设计中,存储器通常采用NAND FLASH,故提出一种基于USB 3.0总线的NAND FLASH数据存储设计。采用FPGA作为逻辑主控单元,选用USB 3.0芯片CYUSB3014作为FPGA与上位机的通信桥梁,并在FPGA软件上设计ECC数据校验纠错以及NAND FLASH的坏块管理。用户可通过上位机实现数据读取、擦除以及分析。实验结果表明,所设计系统可通过USB 3.0接口将NAND FLASH中存储的数据传输到上位机,传输速度实际可达39 MB/s。

通过PO-KELM的3D NAND FLASH寿命预测方法研究

随着半导体行业的快速发展,以及各种芯片国产化的趋势越来越明显,3D NAND FLASH作为当前存储器件的重要代表,其寿命预测对于保障系统可靠性至关重要。因此,通过硬件搭建现场可编程门阵列采集平台,对3D NAND FLASH进行特性分析,在不同擦除/写入次数下模拟FLASH可能发生的不同误码情况,分析耐久性、数据保持特性以及读、写干扰特性的变化趋势。同时提出鹦鹉优化器改进的核极限机器学习机,由于核极限学习机参数寻优困难,鹦鹉优化器通过搜索位置提高参数寻优速度和准确度。采用将已使用的循环次数作为输出结果对FLASH进行寿命预测。实验结果表明,相比其他机器学习,采用鹦鹉优化的核极限学习机预测模型精度可以达到98.5%,在提升训练速度和准确度中具有重要的现实意义。

Revision of CG Flash Density Based on Lightning Location Data

Using the data of the Lightning Location System( LLS) over Hubei Province,through the analysis of the distribution characteristics of CG( Cloud-to-Ground) flash density in 2015,it was found that the layout of the detection station had influence on the spatial distribution of lightning.Grid CG flash density data were used to characterize the spatial distribution of the CG flash,and station distance factor was used to characterize the detection station layout. The result showed that there existed negative correlation between density and factor,significant correlation between the density component and the factor for the lightning current amplitude of 5 to 30 kA,and insignificant correlation between >30 kA of density component and factor. So it is necessary to revise the density to eliminate the influence of the station layout. On the basis of the linear regression method and its residual theory,the revision model of the grid CG flash density and the statistical model of relative detection efficiency were established. The result consistency of segment and non-segmented revision of the density was verified. Through the contrastive analysis of theoretical detection efficiency and relative detection efficiency,the feasibility for revision method of CG flash density and the statistical method of relative detection efficiency was also verified.

基于NAND Flash的FFS设计与实现

NANDFlash以其大容量低价格等优势迅速成为嵌入式系统存储的新宠,因此研究其上的文件系统也日益重要。本文先分析了NANDFlash上FFS的功能结构,然后给出了一个在无OS支持的嵌入式系统中,可与Windows文件系统完全兼容的FFS的设计和实现方案。

A Two-Parameter Description for the Injury Risk of Flash Bangs with Uncertainty

We study the random injury outcome caused by multiple flash bang submunitions on a crowd. We are particularly interested in the fluctuations in injury outcome among individual realizations. Previously, to simulate the distribution of the actual number of injured, we developed a comprehensive Monte Carlo model. While the full computational model is important for thorough theoretical investigations, in practical operations, it is desirable to characterize the phenomenological behavior of injury outcome using a concise model with only one or two parameters. Conventionally, the injury outcome is indicated by the average fraction of injured, which is called the risk of significant injury (RSI). The single metric RSI description fails to capture fluctuations in the injury outcome. The number of injured in the crowd is influenced by many random factors: the aiming error of flash bang mortar, the dispersion of submunitions after mortar burst, the amount of acoustic dose reaching individual subjects, and the biovariability of individual subjects’ reactions to a given acoustic dose. We aim to include these random factors properly and concisely. In this study, we represent the random injury outcome as a compound binomial model, in which the hidden injury probability is drawn from a two-parameter model distribution. We formulate and examine six model distributions for the injury probability. The best performer is a mixture of uniform and triangle distributions, parameterized by (RSI, dp) where dp is the standard deviation of the hidden injury probability. This mixture model predicts the behavior of injury outcome with uncertainty, based solely on the two parameters (RSI, dp) in the flash bang description. For example, we can predict the probability of the injury outcome not exceeding a prescribed tolerance. We advocate the adoption of this two-parameter characterization for flash bangs to replace the single-parameter RSI description. Whenever we need to give a high level coarse description of a flash bang situation, we state that the injury risk is represented by (RSI, dp).

Dark Matter Cosmology and Astrophysics

Hypersphere World-Universe Model (WUM) envisions Matter carried from Universe into World from fourth spatial dimension by Dark Matter Particles (DMPs). Luminous Matter is byproduct of Dark Matter (DM) annihilation. WUM introduces Dark Epoch (spanning from Beginning of World for 0.4 billion years) when only DMPs existed, and Luminous Epoch (ever since for 13.8 billion years). Big Bang discussed in standard cosmological model is, in our view, transition from Dark Epoch to Luminous Epoch due to Rotational Fission of Overspinning DM Supercluster’s Cores and annihilation of DMPs. WUM solves a number of physical problems in contemporary Cosmology and Astrophysics through DMPs and their interactions: Angular Momentum problem in birth and subsequent evolution of Galaxies and Extrasolar systems—how do they obtain it;Fermi Bubbles—two large structures in gamma-rays and X-rays above and below Galactic center;Mysterious Star KIC 8462852 with irregular dimmings;Coronal Heating problem in solar physics—temperature of Sun’s corona exceeding that of photosphere by millions of degrees;Cores of Sun and Earth rotating faster than their surfaces;Diversity of Gravitationally-Rounded Objects in Solar system and their Internal Heat;Lightning Initiation problem—electric fields observed inside thunderstorms are not sufficient to initiate sparks;Terrestrial Gamma-Ray Flashes—bursts of high energy X-rays and gamma rays emanating from Earth. Model makes predictions pertaining to Masses of DMPs, proposes New Types of their Interactions. WUM reveals Inter-Connectivity of Primary Cosmological Parameters and calculates their values, which are in good agreement with the latest results of their measurements.

基于XIP FLASH的嵌入式软件设计与应用

传统NOR FLASH并行地址和数据总线的引脚过多,使电路设计的复杂性增大,同时也会增加电路板布线空间。为了解决这一弊端,部分微控制器支持SPI eXecute in Place(XIP)接口,SPI NOR-FLASH应运而生。基于此,文中提出一种嵌入式软件设计方案。该方案充分发挥XIP FLASH片上执行代码的关键属性,利用GNU编译器的工作原理,通过链接器的链接脚本将嵌入式软件程序存储在XIP FLASH中,运行时代码段和只读数据段存放在XIP FLASH中,只需将数据段及操作XIP FLASH的关键代码搬运至RAM中运行。此外,对嵌入式软件的执行流程进行设计与说明。所提方案简单、易操作,已在单相和三相表载波通信单元、Ⅰ型采集器通信单元、Ⅱ型采集器、集中器载波通信单元得到充分验证,可广泛应用于用电信息采集系统、输配电系统的本地通信等领域。

基于P-BiCS架构的hynix 3D Nand Flash产品结构分析

阐述随着电子产品及大数据信息存储应用需求增加,3D Nand Flash产品市场持续增长。介绍一种主流的3D Nand Flash技术架构,并分析应用P-BiCS架构的hynix 3D Nand Flash产品的结构及成分。

Basic Works of Flash Flood Disaster Analysis and Assessment in Rucheng County of Hunan Province

The method and experience of basic work of flash flood disaster analysis and assessment in early period are introduced in a case of Rucheng County,Chenzhou City,Hunan Province,containing analysis of general situation in county region,excavation of working map information,determination of assessment object list,examination of investigated data,and standardized arrangement of data. Finally,the suggestions for basic work of analysis and assessment are given,which could provide the references for implementing analysis and assessment work of flash flood disaster in other regions.

Modeling the Effect of Irrigation Practices in Flash Floods: A Case Study for the US Southwest

Conventional streamflow forecasting does not generally take into account the effects of irrigation practice on the magnitude of floods and flash floods. In this paper, we report the results of a study in which we modeled the impacts of an irrigated area in the US Southwest on streamflow. A calibrated version of the Variable Infiltration Capacity model (VIC), coupled with a routing algorithm, was used to investigate two strategies for irrigating alfalfa in the Beaver Creek watershed (Arizona, USA), for the period January to March of 2010, at a resolution of 1.8 km and hourly time step. By incorporating the effects of irrigation in artificially maintaining soil moisture, model performance is improved without requiring changes in the resolution or quality of input data. Peak flows in the watershed were found to increase by 10 to 500 times, depending on the irrigation scenario, as a function of the strategy and the intensity of rainfall. The study suggests that both flood control and irrigation efficiency could be enhanced by applying improved irrigation techniques.

重离子辐照引发的25 nm NAND Flash存储器数据位翻转

为研究不同注量下浮栅存储单元位翻转特点及其翻转截面变化,以及重离子入射导致的多单元翻转,以两款25 nm NAND Flash存储器为载体开展了重离子实验研究。实验结果表明,单个重离子在击中存储单元灵敏体积的情况下足以引起位翻转,位翻转比率随着注量累积基本呈线性变化。由于处于编程状态阈值电压分布低压区的存储单元倾向于在相邻或靠近的地址上集中分布,随着注量累积,这类存储单元数量迅速减少,而其他大量存储单元的翻转数增长率变化不明显,因此位翻转截面随注量累积呈下降趋势。重离子导致两款器件出现多单元翻转,多单元翻转呈现单列、双列以及列间隔等结构。利用离子电离径迹模型估算得到离子电离有效径迹半径,可以判定多单元翻转是由于一个离子的电离有效径迹覆盖了多个存储单元。

基于地址映射的NAND Flash控制器设计

针对嵌入式数据采集系统对NAND Flash进行读写控制时出现的坏块问题和磨损失衡问题,对数据采集系统的工作特点进行分析,借鉴闪存转换层的思想,提出了一种基于地址映射的NAND Flash控制方法,通过建立、维护、查询NAND Flash存储块逻辑地址与物理地址之间的映射关系表,实现NAND Flash的坏块管理和磨损均衡功能,同时介绍了使用地址映射方法的NAND Flash控制器设计过程;仿真测试和实际应用结果表明,基于地址映射方法设计的NAND Flash控制器能够识别、管理出厂坏块和突发坏块,均衡存储块的磨损,提高嵌入式数据采集系统的可靠性;该方法实现过程简单,无需移植文件系统,硬件资源要求低,为嵌入式数据采集系统中NAND Flash的读写控制提供了新的思路。

Development of Full Automatic Flash Butt Welding with Digital Control

The hardware and software design of two digital control systems based on 80C196KB MCU for flash butt welder is introduced in this paper.The welding power supply is made of six-phase half-wave rectifier.The welding outer characteristic of welding machine is realized by digital PI algorithm with the voltage close-loop feedback.The flashing curve is finished by elec- tric-hydraulic servo valve.The process control system transfers datum with power supply system by a serial communication inter- face.The parameters of the control systems are collected by photoelectrical seclusion to avoid the disturbing of the electromagnetism in welding process.

Study on Fractional Separation and GC-MS Analysis of Flash Coal Tar Pyrolysed at Low Temperatures

The composition of low temperature pyrolysis coal tar has an effect on its further processing and reasomble utlization In this paper, the compeition or coal tars produced from both low temperature pyroysis in a fluidized bed aud flash pyrolysis with solid heat carrier have been investigated by the methch of fractional seperation and Gas Chromatography-Mass Spectrometry (GC-MS)- It is observed that the degree of coalification maceral and secondary reaction temperature (freeboard temperature in a fluidized bed) have some iufluence on the composition of coal tars- The main compoundes are phenol cresols,xylenols, naphthalene, alkylnaphthalenes, antbraceue, phenanthrene,acenaphthylene, fluoren, indene and so

Thermal Diffusivity and Thermal Conductivity of Epoxy-Based Nanocomposites by the Laser Flash and Differential Scanning Calorimetry Techniques

Nanocomposites were fabricated by using a commercial two part epoxy as a matrix and multiwalled carbon nanotubes, graphite fibers and boron nitride platelets as filler materials. Multiwalled carbon nanotubes (MWCNTs) that were produced by chemical vapor deposition were found to produce nanocomposites with better thermal diffusivity and thermal conductivity than the MWCNTs that were produced by the combustion method. Compared to the MWCNTs produced by both methods and graphite fibers, boron nitride produced nanocomposites with the highest thermal conductivity. Specific heat capacity was measured by using differential scanning calorimetry and thermal diffusivity was measured by using the laser flash.

基于内建自测试电路的NAND Flash测试方法

随着NAND Flash在存储器市场中的占比与日俱增,对NAND Flash的测试需求也越来越大。针对NAND Flash存储器中存在的故障类型进行讨论,并对现有测试算法进行分析,为提高故障覆盖率以及降低测试时间,对现有的March-like测试算法做出改进,改进算法比March-like算法的故障覆盖率提高了16.7%,测试时间减少了30%。完成存储器内建自测试(MBIST)电路设计,设计了FPGA最小系统板并进行板级验证,结果验证了MBIST电路以及改进的测试算法的可行性。

12 bit 100 MS/s Flash-SAR混合模数转换器设计

针对传统逐次逼近型模数转换器(Successive Approximation Register Analog-to-Digital Converter,SAR ADC)采样率和能量效率低等问题,设计了一款快闪型(Flash)与逐次逼近型(SAR)相结合的新型混合架构模数转换器。利用快闪型ADC一个时钟周期内可以转换出多个数字码的优势,提高了ADC的采样率。采用新型混合开关切换策略与分段电容阵列技术相结合提升了ADC的能量效率,减小了版图面积。同时,电路采用预放大动态锁存比较器以降低噪声和失调对ADC性能的影响。采用SMIC 0.11μm工艺后,仿真结果表明,在1.2 V的工作电压下,当采样速率为100 MS/s,输入信号频率为45.04 MHz时,输出信号的信号噪声失真比(Signal-to-Noise-and-Distortion Radio,SNDR)为69.26 dB,无杂散动态范围(Spurious-free Dynamic Range,SFDR)为82.10 dB,有效位数(Effective Numbers of Bits,ENOB)达到11.21 bit,功耗为5.72 mW,版图尺寸为380μm×110μm。

PRELIMINARY STUDY ON FLASH FLOODS IN TARIM RIVER BASIN

Flash floods are the important events of the hydrological regime of rivers in arid areas. In the Tarim River, northwestern china, flash flood are being monitored. The observed data and investigation demonstrate the difference in time, place, fraquency and intensity of their occurrences. In this paper two main flash fled are put forward, they are rainstorm flash flood (RFF) and glacier lake outburst flood(GLOF). Two cases of flash flood in the two tributaries of the Tarim River presented in this paper. It analyses and compares the causes and the development of the two kinds of flash floods.Through further discussion about influence of flash floods on the main channel of the Tarirn River, conclusion can be drawn that the greatest flood in record of the main channel come from the GLOF of the upper reaches of the Kunmalik River, especially augmented by great ablation flood. Finally the advantages and disadvantages from flash floods to the environment of the catchment are demonstrated in the paper.

Investigation of gate oxide traps effect on NAND flash memory by TCAD simulation

The effects of gate oxide traps on gate leakage current and device performance of metal–oxide–nitride–oxide–silicon(MONOS)-structured NAND flash memory are investigated through Sentaurus TCAD. The trap-assisted tunneling(TAT)model is implemented to simulate the leakage current of MONOS-structured memory cell. In this study, trap position, trap density, and trap energy are systematically analyzed for ascertaining their influences on gate leakage current, program/erase speed, and data retention properties. The results show that the traps in blocking layer significantly enhance the gate leakage current and also facilitates the cell program/erase. Trap density ~10^(18) cm^(-3) and trap energy ~ 1 eV in blocking layer can considerably improve cell program/erase speed without deteriorating data retention. The result conduces to understanding the role of gate oxide traps in cell degradation of MONOS-structured NAND flash memory.

双源CT Flash模式冠状动脉CT血管成像在PCI术后随访中的应用价值

目的:探讨双源CT Flash模式冠状动脉CT血管成像(coronary CT angiography,CCTA)在经皮冠状动脉介入治疗(percutaneous coronary intervention,PCI)术后随访中的应用价值,以对患者PCI术后情况作出准确判断。方法:选取PCI术后患者106例,可评价支架147枚。随机分为A、B 2组,A组行Flash模式扫描,B组行常规回顾性心电门控扫描。以冠状动脉造影(coronary angiography,CAG)为金标准评价Flash模式CCTA对支架内再狭窄(in-stent restenosis,ISR)的敏感性、特异性、阳性预测值和阴性预测值。对比A、B 2组检查方案在图像质量、辐射剂量、造影剂用量方面的差异。应用SPSS 19.0进行统计分析。结果:双源CT Flash模式CCTA ISR诊断的敏感性、特异性、阳性预测值、阴性预测值分别为85.7%、95.1%、80.0%和96.7%。A组与B组在图像质量方面差异无统计学意义(P>0.05),A组在造影剂用量、辐射剂量方面均显著低于B组,差异有统计学意义(P<0.05)。结论:双源CT Flash模式CCTA在PCI术后随访中的ISR诊断准确率高,与常规回顾性心电门控扫描相比患者所受辐射剂量小、造影剂用量少,可以作为排除PCI术后ISR的可靠检查方法。