一种新型三坐标雷达点迹提取器的设计

在目标信号检测模块的基础上增加了测有计算模块，构成一种新型的单脉冲雷达点迹提取器，显著提高了雷达系统潜在的处理能力。     

用φ20mm离心萃取器两步法制取高纯钇

本文研究了中钇富镧稀土的氧化物溶液在环烷酸中的萃取行为，测定了镧钇组成、温度变化与分离系数的关系；在Ｐ＿（５０７）体系中研究了ｐＨ值与分配比的关系；提出用环烷酸、Ｐ＿（５０７）两种萃取剂制备高纯钇的工艺流程。用８４台φ２０ｍｍ离心萃取器进行了一个月的台架试验，结果证明两种萃取剂有很好的互补性，在满足钇的纯度要求下有较高收率。离心萃取器具有易分相、体系存留量少、液流密闭性好等优点，它更适宜于粘度大、级数多、产品纯度要求高的体系。     

分子筛辅助人参须根粉快速制备人参皂苷Rg5的工艺研究

利用多功能改进型索氏提取器为提取工具,以人参须根粉为原料,盐酸为催化剂,分子筛辅助下高效制备了稀有人参皂苷Rg5,并通过单因素实验优化了工艺条件。实验结果表明：当以30 mL的甲醇为溶剂、加入0.3 g 4 A分子筛、于65 ℃提取4 h时,人参总皂苷的提取率达到10.2%,稀有人参皂苷Rg5的得率达到3.20%,与传统索氏提取器相比可以显著提高人参皂苷Rg5的制备效率。分子筛辅助下利用多功能改进型索氏提取器从人参须根粉提取制备稀有人参皂苷Rg5,不仅得率较高,而且操作简单快捷,是一种快速制备人参皂苷Rg5的工艺方法。     

Stage-efficiency of centrifugal extractor used in nuclear industry

1　INTRODUCTIONComparedwithamixer settlerorpulsedcolumnusedinthenuclearfuelreprocessingextraction pro cesses,ashort residence timecentrifugalextractorcatchesresearcher seyesbecauseofthe goodphaseseparationandasmallhold upvolume .Itshowsthefollowingadvantagesinthenuclearindustry[1] :1)Reducingsolventdegradationduetoradiation ;2 )Reducinginventoryofaqueousandorganicphases ,whichgivesrapidstart upandshut down ;3)Com pactdesignthatcontributestothereductionofplantcost .Manydifferenttypesofcen…     

An alignment-free fingerprint bio-cryptosystem based on modified Voronoi neighbor structures

Bio-cryptography is an emerging security technology which combines cryptography with biometrics. A good bio-cryptosystem is required to protect the privacy of the relevant biometric data as well as achieving high recognition accuracy. Fingerprints have been widely used in bio-cryptosystem design. However, fingerprint uncertainty caused by distortion and rotation during the image capturing process makes it difficult to achieve a high recognition rate in most bio-cryptographic systems. Moreover, most existing bio-cryptosystems rely on the accurate detection of singular points for fingerprint image pre-alignment, which is very hard to achieve, and the image rotation transformation during the alignment process can cause significant singular point deviation and minutiae changes. In this paper, by taking full advantage of local Voronoi neighbor structures (VNSs), e.g. local structural stability and distortion insensitivity, we propose an alignment-free bio-cryptosystem based on fixed-length bit-string representations extracted from modified VNSs, which are rotation- and translation-invariant and distortion robust. The proposed alignment-free bio-cryptosystem is able to provide strong security while achieving good recognition performance. Experimental results in comparison with most existing alignment-free bio-cryptosystems using the publicly-available databases show the validity of the proposed scheme.     

撞击流-旋转填料床萃取器传质性能研究

以磷酸三丁酯(煤油)-苯酚-水为试验体系，研究了IS—RPB萃取器的传质性能。在研究主要操作参数对萃取级效率影响的基础上，确定了最适宜的操作条件，得到了97％以上萃取级效率。试验结果表明，撞击流-旋转填料床萃取器是一种新型快速高效的萃取设备。     

一种基于模糊提取的虹膜鉴别方案

模糊提取从生物特征输入中以容错的方式可靠地提取出均匀分布的随机密钥,当输入发生变化且变化很小时,该密钥可以保持不变,研究了当汉明距离作为生物特征匹配的度量标准时,结合纠错编码学与传统密码学实现模糊提取的虹膜鉴别方法,分析了虹膜特征编码之间的差异对正确鉴别性能的影响,设计了重复码和Reed-Solomon码的两层级联纠错编码方案,并对128只虹膜的各3个样本进行了模拟实验,所给方案使用户虹膜特征模板的安全性和隐私性得到了有效保护,并能够支持用户虹膜的注册更新,此外,实验表明该方案同时具有较理想的识别性能.     

Zero-knowledge proofs of retrievability

Proof of retrievability (POR) is a technique for ensuring the integrity of data in outsourced storage services.In this paper,we address the construction of POR protocol on the standard model of interactive proof systems.We propose the first interactive POR scheme to prevent the fraudulence of prover and the leakage of verified data.We also give full proofs of soundness and zero-knowledge properties by constructing a polynomial-time rewindable knowledge extractor under the computational Diffie-Hellman assump...     

φ50 mm核用离心萃取器的研制及其水力学性能

离心萃取器具有许多优点,在核工业中正日益受到重视.最近,清华大学核能和新能源技术研究院在成功研制φ10 mm核用离心萃取器和φ70 mm核用离心萃取器的基础上,又研制出φ50 mm核用离心萃取器.该样机采用了模块化设计和陶瓷轴承.以水-煤油为体系研究了其水力学性能.实验结果表明:当重相堰个直径为26、28、30 mm,转速为2 100～3 000 r/min,实验操作流比(A/O)为0.1～10时,其处理能力可达160 L/h.另外,测定了该样机的级存留量为310～340 mL.     

Mini Liquid‐Liquid Extractor without Moving Parts Based on the Coanda Effect

A mini liquid‐liquid extractor was designed based on a feedback fluidic oscillator. According to the Coanda effect, the designed oscillator with two feedback channels enables good mixing of the aqueous and organic phases. Co‐current liquid‐liquid extraction was performed in the mini extractor, and it was visually observed that the aqueous phase was dispersed into small droplets because of fluidic oscillation and vortex formation. The aqueous phase was more effectively dispersed at the stage near the outlet and with increasing flow. Several tests were performed for evaluating the extraction performance of the extractor using 30 % tributyl phosphate‐kerosene and 3 M HNO₃ solutions as the organic and aqueous phases, respectively. The obtained extraction efficiency was close to the equilibrium efficiency, indicating that this extractor has the potential for liquid‐liquid extraction of hazardous liquids.