山东苍山县大蒜中硒含量测定

采用荧光分光光度法分别对山东省苍山县和济南产大蒜中硒含量进行了测定,结果显示,苍山县大蒜中的硒含量明显高于济南产大蒜。苍山县居民素有种蒜、食蒜习惯,因此长期摄食含硒高的大蒜可能与此地区胃癌发病率低有一定关系。     

蓖麻油碱炼脱酸的理论与实践

采用理论与实践相结合的笔法,论述了理论指导下的蓖麻油碱炼脱酸过程,又通过蓖麻油碱炼脱酸的生产实践验证,丰富着经典理论,提出蓖麻油碱炼脱酸的理论,从而,将科技转化为生产力。     

固态发酵井冈霉素废渣生产饲料蛋白的研究

对同化淀粉,纤维二糖及Ｄ－木糖能力强的糖化酵母菌Ｙ９６０１株在井冈霉素废渣固态发酵法生产饲料蛋白中的应用进行了工艺条件的优化研究。试验结果表明,发酵产物酵母数达到４．８－４．９×１０＾９个／ｇ,粗蛋白从３２．１％提高到４５．６％,真蛋白从原来的２９．８％提高是３９．３０％,真蛋白实际提高量４．７３％,氨基酸总量３６．５６％。     

A fast bit-loading algorithm for high speed power line communications

Adaptive bit-loading is a key technology in high speed power line communications with the Orthogonal Frequency Division Multiplexing (OFDM) modulation technology. According to the real situation of the transmitting power spectrum limited in high speed power line communications, this paper explored the adaptive bit loading algorithm to maximize transmission bit number when transmitting power spectral density and bit error rate are not exceed upper limit. With the characteristics of the power line channel, first of all, it obtains the optimal bit loading algorithm, and then provides the improved algorithm to reduce the computational complexity. Based on the analysis and simulation, it offers a non-iterative bit allocation algorithm, and finally the simulation shows that this new algorithm can greatly reduce the computational complexity, and the actual bit allocation results close to optimal.     

Cooperative Transmissions in 5G Large-scale Relay Systems: How to Keep a Balance Between Performance and Complexity?

This paper presents a generalized i-vector representation framework with phonetic tokenization and tandem features for text independent as well as text dependent speaker verification. In the conventional i-vector framework, the tokens for calculating the zero-order and first-order Baum-Welch statistics are Gaussian Mixture Model (GMM) components trained from acoustic level MFCC features. Yet besides MFCC, we believe that phonetic information makes another direction that can benefit the system performance. Our contribution in this paper lies in integrating phonetic information into the i-vector representation by several extensions, forming a more generalized i-vector framework. First, the tokens for calculating the zero-order statistics is extended from the MFCC trained GMM components to phonetic phonemes, trigrams and tandem feature trained GMM components, using phoneme posterior probabilities. Second, given the zero-order statistics (posterior probabilities on tokens), the feature used to calculate the first-order statistics is also extended from MFCC to tandem feature, and is not necessarily the same feature employed by the tokenizer. Third, the zero-order and first-order statistics vectors are then concatenated and represented by the simplified supervised i-vector approach followed by the standard Probabilistic Linear Discriminant Analysis (PLDA) back-end. We study different token and feature combinations, and we show that the feature level fusion of acoustic level MFCC features and phonetic level tandem features with GMM based i-vector representation achieves the best performance for text independent speaker verification. Furthermore, we demonstrate that the phonetic level phoneme constraints introduced by the tandem features help the text dependent speaker verification system to reject wrong password trials and improve the performance dramatically. Experimental results are reported on the NIST SRE 2010 common condition 5 female part task and the RSR 2015 part 1 female part task for text independent and text dependent speaker verification, respectively. For the text independent speaker verification task, the proposed generalized i-vector representation outperforms the i-vector baseline by relatively 53 % in terms of equal error rate (EER) and norm minDCF values. For the text dependent speaker verification task, our proposed approach also reduced the EER significantly from 23 % to 90 % relatively for different types of trials.     

单模光纤受激喇曼散射的脉冲倒空

单模光纤SRS的实验用的是Nd:YAG调Q倍频激光作泵浦源,用快速雪崩二极管探测光脉冲信息,用存储示波器记录波形,光路如图1。图中1是JGM-1型色心调QNd:YAG激光器,倍频后(0.53μm)脉宽为20ns,输出能量为125μJ～100mJ。2是滤去1.06μm剩余光的滤光片,3是分束片,4是LPE-IA激光功率/能量计,以监视输入能量,5、7是耦合透镜,6是光纤,8是单色仪,9是Ge-     

Metal-to-metal antifuse with low programming voltage and low on-state resistance

This paper describes and analyses the impact of the Ti layer, which is embedded between the insulator and top electrode, on the programming characteristic of the Al-HfO₂-Al antifuse. The programming voltage of the antifuse with 120 Å HfO₂ is properly reduced from 5.5 to 4.6 V with an embedded Ti layer. Low on-state resistance (~19 Ω) and low programming voltage (4.6 V) is demonstrated in the embedded Ti antifuse with 120 Å HfO₂ while keeping sufficient off-state reliability. The antifuse embedded with a Ti layer between the insulator and top electrode has been developed and has potential in field programmable devices.     

局部火灾下钢框架结构整体性能的非线性分析

本文用有限元法对局部火灾下钢框架结构的整体性能进行了分析，分析中考虑了包含温度变形影响的几何非线性、随温度升高材料性能的不断变化以及杆件截面温度分布不均匀等因素的影响。基于虚功原理，文章导出了温度荷载矩阵、温度几何刚度矩阵等概念，并编制了用于计算任意温度状态下结构的极限承载力或任意荷载状态下结构的温度极限值的有限元程序。同国外试验结果的比较验证了本文分析的正确性。     

认知Mesh网络的动态分层图路由模型及路由策略

该文提出了在认知无线电Mesh网络环境下的动态分层图路由模型,该模型将节点感知范围内的信道可用性用两状态离散时间马尔可夫链建模,建立认知无线电Mesh网络拓扑和连通性的动态模型。基于该模型提出了一种跨层设计的动态接口分配方案。仿真结果表明,动态分层图模型在适应接入频谱的动态变化和描述认知无线电Mesh网络的拓扑结构方面,表现出比静态分层图模型更加优异的性能。     

A Low Loss X-Band Quasi-Elliptic Ferroelectric Tunable Filter

A compact high quality factor four-pole X-band tunable quasi-elliptic bandpass filter is presented in this letter. The filter is enabled by high-Q ferroelectric barium strontium titanate capacitors and open-loop resonators. The central frequency of 8.35 GHz and the frequency tuning range of 500 MHz (6%) are achieved with a dc bias voltage of 30 V. The selective filter has a fractional 1 dB bandwidth ranging from 5.5% up to 7.3%. The measured insertion loss and return loss are 5.7-3.5 dB and 10.2-7.9 dB, respectively, with a dc bias range of 0 to 30 V. To the best of our knowledge, this is the best analog tunable performance and selectivity in X-band.