Amplitudes, rates, periodicities and causes of temperature variations in the past 2485 years and future trends over the central-eastern Tibetan Plateau

Amplitudes, rates, periodicities, causes and future trends of temperature variations based on tree rings for the past 2485 years on the central-eastern Tibetan Plateau were analyzed. The results showed that extreme climatic events on the Plateau, such as the Medieval Warm Period, Little Ice Age and 20th Century Warming appeared synchronously with those in other places worldwide. The largest amplitude and rate of temperature change occurred during the Eastern Jin Event (343-425 AD), and not in the late 20th century. There were significant cycles of 1324 a, 800 a, 199 a, 110 a and 2-3 a in the 2485-year temperature series. The 1324 a, 800 a, 199 a and 110 a cycles are associated with solar activity, which greatly affects the Earth surface temperature. The long-term trends (>1000 a) of temperature were controlled by the millennium-scale cycle, and amplitudes were dominated by multi-century cycles. Moreover, cold intervals corresponded to sunspot minimums. The prediction indicated that the temperature will decrease in the future until to 2068 AD and then increase again.     

Ancient DNA sequences of rice from the low Yangtze reveal significant genotypic divergence

Rice (Oryza sativa) was first domesticated in the lower and middle Yangtze regions of China, and rice remains have been found in many Chinese archaeological sites. Until now, only phenotypic archeobotanical evidence, such as the spikelet bases of ancient grains, has been used to speculate on the domestication process and domestication rate of rice. In this study, we sequenced 4 genomic segments from rice remains in Tianluoshan, a site of the local Hemudu Neolithic culture in the low Yangtze and two other archaeological sites (~2400 and 1200 BC, respectively). We compared our sequences with those of the current domesticated and wild rice (O. rufipogon) populations. At least two genotypes were found in the remains from each site, suggesting a heterozygotic state of the rice seeds. One ancient genotype was not found in the current domesticated population and might have been lost. The rice remains belonged to the japonica group, and most if not all were japonica-type, suggesting that the remains might be at an early stage of indica-japonica divergence or an indica-japonica mixture. We also identified sequences with significant similarity to those from species of Sapindales, Zygophyllales, and Brassicales, which is consistent with the identification of other plant remains in the Tianluoshan site and the common rice field weeds such as mustards in southern China.     

Dissolved organic nitrogen (DON) in the processes of polluted source water treatment

Dissolved organic nitrogen (DON) is currently considered to be one of the most important issues in drinking water field due to its formation of nitrogenous disinfection byproducts. This paper deals with DON concentrations in typical processes of a water treatment plant. The results show that very little DON is removed by these processes. Furthermore, biological activity in some processes can even increase DON concentration and decrease the ratio of dissolved organic carbon/DON, which may pose a risk to drinking water safety.     

激光动态法测定DL-酒石酸有机溶剂中的溶解度

利用一套激光动态监视、升温速率可控的溶解度测量系统装置，测定了常压下温度范围为277.15~334.15 K内 DL-酒石酸在6种纯溶剂中的溶解度数据，并用Apelblat方程、λh方程和NRTL方程对实验数据进行了关联。结果发现对于纯溶剂体系，DL-酒石酸溶解度的计算值与实验测定值吻合良好；选用的3种方程在所研究的温度和浓度范围内是适用的，可以为DL-酒石酸的结晶分离过程提供数据支持。     

钼粉还原自动化生产线装料称重装置的设计

针对钼粉还原炉自动化生产线的工艺需求,设计了一种装料称重刮平与现场控制为一体的钼粉自动化装料称重装置。详细论述了该装置的机构组成及工作原理,并以ADuC824单片机为主控单元、EPM7128为逻辑信号处理单元构建完整的软硬件测控单元平台,设计制作了相应的部件单元和软件程序,并进行了现场试运行实验。实验结果表明,该称重装置重复性测量精度标准差为1.5 g,最大相对误差为0.11%,达到了钼粉还原炉自动化生产线所要求的称重误差控制要求。     

随机非对称耦合控制螺旋波和时空混沌

通过引入随机非对称耦合方法对螺旋波和时空混沌进行控制,数值模拟结果表明:在选择适当的控制参数下,螺旋波和时空混沌能被控制并最终达到稳定的靶波态,实现了对螺旋波和时空混沌的有效控制,在一定的耦合强度c和随机耦合概率p下,两个不同的系统之间存在相同步和完全同步现象,通过计算瞬时平均相位差△φ和泊松系数γ进一步验证了这一现象...     

Consecutive tracking for ballistic missile based on bearings-only during boost phase

This paper proposes a modified centralized shifted Rayleigh filter(MCSRF) algorithm for tracking boost phase of ballistic missile(BM) trajectory with a highly nonlinear dynamical model based on bearings-only.This paper contributes three folds.Firstly,the mathematical model of an MCSRF for multiple passive sensors is derived.Then,minimum entropy based onedimensional optimization search to adaptively adjust the probability of the different filters for real time state estimation is deployed.Finally,the unscented transform(UT) is introduced to resolve the asymmetric state estimation problem.Simulation results show that the proposed algorithm can consecutively track the BM precisely during the boost phase.In comparison with the unscented Kalman filter(UKF) algorithm,the proposed algorithm effectively reduces the tracking position and velocity root mean square(RMS) errors,which will make more sense for early precision interception.     

准幻方矩阵及其判定

给出了双心矩阵和双随机矩阵的一种推广矩阵——准幻方矩阵的定义,即设A∈Rn×n,如果A的每一行元素之和与每一列元素之和都为同一个常数,则称矩阵A为准幻方矩阵,得到了非负矩阵为准幻方矩阵的几个充要条件,并讨论了双心矩阵和双随机矩阵几个判定定理,得出了一些新的结果.     

基于消退论谈民办高校图书馆电子阅览室的服务工作

从高校图书馆电子阅览室的消退论入手,分析了民办高校图书馆电子阅览室进入消退阶段的主要因素,探讨了民办高校图书馆电子阅览室如何有效地开展信息服务工作的对策。     

基于“以人为本”理念的道路设计

市政道路人性化和环境理念目前还是一个较新的方向,也是市政道路设计发展的必然趋势。传统的市政道路设计主要满足道路的运输功能要求。文章结合实际经验,从以人为本和道路与环境的协调性角度出发,对市政道路设计进行初步探讨。