Hardware optimization of SHA-256 hash operation unit

在信息安全领域,SHA-256算法被广泛应用于数字签名、身份认证、消息完整性验证等方面。为满足应用对SHA-256算法运算速度上的要求,本文利用流水线的设计思想,提出了一种四级流水的哈希计算结构,提高了运算速度,增大了吞吐率。最终,本文在Virtex-7系列FPGA开发板上实现了SHA-256哈希运算单元,最高工作频率可达到319MHz,吞吐率达到2405Gbps,吞吐率面积比达到2.529Mbps/Slice。SHA-256 algorithm is widely used in digital signature, identity authentication, message integrity verification etc. In order to speed up SHA-256 algorithm computing, a four-stage pipeline processing for SHA-256 is proposed. Implemented on virtex-7 FPGA series, the proposed SHA-256 can work at 319 MHz, and archive a throughput of 2405 Gbps.The ratio of throughput/area is 2.529Mbps/Slice

破产会计理论结构体系简论

破产会计理论结构体系简论牛秀玲王健破产会计做为会计的一个分支，具有与一般会计相同的理论结构体系，但在具体内容上，又具有本身的特点。本文拟就此做一探讨。一、破产会计的概念破产会计是建立在特定主体范围内的，由清算组按照《破产法》和有关公认会计原则等的规范..

Loop Closure Detection Algorithm Based on Greedy Strategy for Visual SLAM

动态环境与视觉混淆严重影响视觉闭环检测性能.基于贪心策略,提出了一种在线构建视觉词典的闭环检测算法.算法优先处理Surf描述与已有单词Surf描述欧式距离最大的特征点,改进特征点与单词Surf描述最近邻的约束条件,生成了表征性能强、量化误差小的视觉词典,算法具备实时性,并在动态环境图像集与视觉混淆多发生的图像集上,在确保100%,准确率的条件下,最大召回率分别提升了5%,与4%,.The performance of loop closure detection is seriously affected by dynamic objects and perceptual aliasing in the environment. Based on greedy strategy, a real-time loop closure detection approach using online visual dictionary is proposed. The process of dictionary construction gives priority to dealing with Surf feature that has the maximum Euclidean distance from the closest vocabulary word. A more discriminative and representative visual vocabulary is produced through adding constraint condition to the nearest neighbor distance. This visual vocabulary guarantees a small quantization error. The proposed approach meets real-time constraints. Experiments based on datasets from dynamic environments and visually repetitive environments demonstrated that the largest recall rate increased by 5% and 4% respectively at 100% precision. © 2017, Editorial Board of Journal of Tianjin University(Science and Technology). All right reserved.国家自然科学基金资助项目(61274133). Supported by the National Natural Science Foundation of China(61274133

Loop Closure Detection Algorithm Based on Greedy Strategy for Visual SLAM

动态环境与视觉混淆严重影响视觉闭环检测性能.基于贪心策略,提出了一种在线构建视觉词典的闭环检测算法.算法优先处理Surf描述与已有单词Surf描; 述欧式距离最大的特征点,改进特征点与单词Surf描述最近邻的约束条件,生成了表征性能强、量化误差小的视觉词典,算法具备实时性,并在动态环境图像集; 与视觉混淆多发生的图像集上,在确保100%,准确率的条件下,最大召回率分别提升了5%,与4%,.The performance of loop closure detection is seriously affected by; dynamic objects and perceptual aliasing in the environment.Based on; greedy strategy,a real-time loop closure detection approach using online; visual dictionary is proposed.The process of dictionary construction; gives priority to dealing with Surf feature that has the maximum; Euclidean distance from the closest vocabulary word.A more; discriminative and representative visual vocabulary is produced through; adding constraint condition to the nearest neighbor distance.This visual; vocabulary guarantees a small quantization error.The proposed approach; meets real-time constraints.Experiments based on datasets from dynamic; environments and visually repetitive environments demonstrated that the; largest recall rate increased by 5%, and 4%, respectively at 100%,; precision.国家自然科学基金资助项

Optimization of β-Cyclodextrin Inclusion Technology of Volatile Oil from Pueraria Compound by Orthogonal Design

目的优选葛根复方挥发油的包合工艺,提高制剂的稳定性。方法采用饱和水溶液法制备包合物,以挥发油中藁本内酯、桂皮醛、甲基丁香酚包合率及包合物得率为综合评价指标,采用正交试验法考察挥发油与β-环糊精的比例、包合时间、包合温度对包合工艺的影响,优化得到葛根复方中挥发油的最优包合工艺。结果葛根复方中挥发油的最佳包合工艺条件为挥发油与β-环糊精比例为1∶8,包合温度为30℃,包合时间为1h,验证试验中,藁本内酯、桂皮醛及甲基丁香酚的包合率为别为86.58%±0.009%,73.34%±0.001%,68.89%±0.020%,包合物得率为67.98%±0.047%。结论所确定的包合工艺挥发油的包合率高、工艺稳定可行。Objective To obtain the optimized technology of volatile oil from Pueraria Compound with β-Cyclodextrin（ β-CD）. Methods The inclusion compound was prepared by saturated peroxide solution method. In order to optimize inclusion technology,orthogonal design was performed,with the content of multi-target ingredient,such as ligustilide,cinnamic aldehyde,methyleugenol and the yield of inclusion as comprehensive evaluation indexes. Three factor was performed,the ratio of volatile oil（ m L） to β-CD（ g）,the inclusion temperature and the inclusion time. Results The optimum conditions for inclusion process were as follow： the ratio of volatile oil（ m L） to β-CD（ g） was 1： 8,the inclusion temperature was 30℃ and the inclusion time was 1h. With the optimum inclusion condition,the content of ligustilide,cinnamic aldehyde and methyleugenol and the yield of inclusion were 86. 58% ± 0. 009%,73. 34% ± 0. 001%,68. 89% ± 0. 020%,and 67. 98% ± 0. 047%,respectively.Conclusion The optimum inclusion condition was stable and reproducible with a high inclusion yield.国家自然科学基金（No.81270901）;上海市教委基金（No.15cxy21

Optimization of extraction for volatile oils and water-soluble constituents in Compound Gegen Decoction

目的优化葛根复方挥发油和水溶性成分提取工艺。方法以浸泡时间、提取时间、加水量为影响因素,综合评分(藁本内酯、桂皮醛、甲基丁香酚含有量,葛根素、阿; 魏酸转移率,干膏得率)为评价指标,正交试验优化提取工艺。结果最佳条件为浸泡时间30 min,提取2次,每次加入10倍量水,第1次提取5; h以收集挥发油,第2次提取1 h以收集水溶性成分,藁本内酯、桂皮醛、甲基丁香酚含有量分别为0.806、1.111、1.635 mg; /g,葛根素、阿魏酸转移率分别为61.62%、73.38%,干膏得率为34.42%。结论该方法稳定可行,可用于提取葛根复方挥发油和水溶性成分。国家自然科学基金; 上海市教委基

小槐花的化学成分研究

目的:系统研究中药小槐花中的化学成分。方法:利用大孔树脂,Sephadex LH-20,ODS及正相硅胶柱等色谱手段进行分离,通过多种波谱学数据分析进行化合物的结构鉴定。结果:从小槐花60%乙醇提取物中分离得到15个化合物,经结构鉴定分别为豆甾醇(1),β-谷甾醇(2),柠檬酚(3),黄槿酮A(4),异柠檬酚(5),kenusanone I(6),neophellamuretin(7),清酒缸酚(8),古柯三醇(9),黄槿酮D(10),山柰酚(11),8-prenylquercetin(12),leachianone G(13),5,7,4'-三羟基-二氢黄酮醇(14),4H-1-benzopyran-4-one,2-(3,4-dihydroxyphenyl)-2,3-dihydro-3,5,7-trihydroxy-8-(3-methyl-2-butenyl)-,(2R-trans)-(9CI)(15)。结论:除化合物8外,所有化合物均为从该种植物中首次分离得到

50味中药及其复方与抗生素对河流弧菌的体外抑菌作用

用牛津杯法选择大黄、黄柏、黄连等50种单味中药进行河流弧菌、金黄色葡萄球菌体外抑菌试验,并以抗菌活性较好的药物组成二联、三联复方,药物质量浓度分别为60和240 mg·mL-1,进行中药复方抗菌活性研究,同时用抗生素进行河流弧菌药敏试验。目的是筛选出对河流弧菌敏感的中草药、抗生素及其复方。结果表明,黄连、诃子等单方对河流弧菌抑菌作用明显,为极敏感;在60 mg·mL-1低药物浓度时,黄柏、黄连组成的复方对河流弧菌抑菌作用为极敏感;在240 mg·mL-1药物浓度时,黄柏、黄连等组成的9个复方中药对河流弧菌抑菌作用属极敏感,黄连、板蓝根、黄柏等4个复方中药对河流弧菌的抑菌作用明显,为极敏感。河流弧菌对恩诺沙星、盐酸多西环素、氟苯尼考、土霉素及甲氧苄啶/磺胺甲噁唑5种药物高度敏感。部分中药对河流弧菌抑制作用不明显,黄连、板蓝根、黄柏等4个三联复方中药药效最强。可组成多种三联复方中药或中西药联用复方,均有良好的抑制作用。2018年开放课题基金项目(LYC2018RS04,闽海鸥[2018]31号)福建省自然基金项目(2016J01167,2018J01455)国家自然科学基金(31702384,31502194)福建省科技重大专项(2016NZ0001-3)2017年集美大学研究生教育教学改革研究项目(集大研No.[2017]18号)教育部鳗鱼工程研究中心开放基金项目(RE201704

新时代一流本科教育的重建(笔会)

继\"双一流\"建设正式实施,建设一流本科教育成为我国高等教育发展的又一重要任务。一流本科教育的概念具有历史性、时代性、国别性和普遍性。\"以本为本\"的提出重在强调本科教育的最基础地位、本科教学的最基本职能、本科教育的最基本特质。建设一流的本科教育首先需要有先进的教育理念,明确其基本定位、指导思想、主要内涵与实施路径。提高本科教育质量的关键在于结构化育人模式,而通过学生课程学习经历调查可以评估本科教与学的质量。在建设一流本科教育中,还要重视学业考核制度建设,推进教育评价改革,构建良好的师生关系。对于一流研究型大学,要凸显一流本科的特色,处理好本科教育与学科发展的关系。国家社科基金“十三五”规划2017年度教育学重大招标课题“‘双一流’建设背景下高校学科调整与建设研究”(项目编号:VIA170003)的阶段性研究成果;;教育部人文社科重点研究基地重大项目“中国特色的大学内部治理结构与质量保障机制建设研究”(项目编号:18JJD880005)的阶段性研究成果;;国家社科基金(管理学)一般项目“管办评分离背景下大学社会评价体系和机制研究”(项目编号:16BGL172)的阶段性研究成果;;中国高教学会“中国高等教育改革发展重大理论实践问题研究”之“一流大学建设与一流本科教育的研究”(项目编号:2017ZD02)的阶段性研究成果