论西北少数民族地方文献资源的数字化建设

从新疆维吾尔自治区图书馆网站数字资源建设和地方文献特藏部的实际出发,结合西北地区少数民族文献的发展,对本馆的特色资源数字化建设做了初步研究。     

县市级公共图书馆人力资源现状与存在问题的个案分析——以昌吉州各图书馆为例

对昌吉州各公共图书馆人力资源管理的现状进行了调研,在调研基础上,分析了昌吉州各公共图书馆人力资源管理存在的主要问题及其产生的原因。     

网络环境下非英语专业学生听力自主学习的研究

网络环境下的自主学习是深化大学英语教学改革和转变教学模式的有效途径。本研究旨在分析高职院校非英语专业学生在网络环境下进行英语听力自主学习的可行性．并对其中可能存在的问题提出相应的建议。     

Cu2S nanocrystals incorporated highly efficient non-fullerene ternary organic solar cells

Here, we report Cu₂S nanocrystals based non-fullerene ternary polymer solar cells by incorporating Cu₂S in conjugated polymer (PBDB-T: poly[(2,6-(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)-benzo[1,2-b:4,5-b′]dithiophene))-alt-(5,5-(1′,3′-di-2-thienyl-5′,7′-bis(2-ethylhexyl) benzo[1′,2′-c:4′,5′-c′]dithiophene-4,8-dione))]) and small molecule non-fullerene compound (ITIC:3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2′,3′-d′]-s-indaceno[1,2-b:5,6-b′]dithiophene). The devices were fabricated in inverted configuration i.e. ITO/ZnO/PBDB-T: Cu₂S NCs: ITIC/MoO₃/Ag. Effect of concentration of Cu₂S nanocrystals on the performance parameters of PBDB-T: ITIC based organic solar cells is studied. An enhancement in the power conversion efficiency from 8.24% to 9.53% is achieved for the optimum concentration of Cu₂S nanocrystals in the organic photoactive blend. The cause of improvement in the performance parameters of the device is investigated by means of the light intensity dependent electrochemical impedance spectroscopy and atomic force microscopy. It is found that the devices with Cu₂S nanocrystals have less trap-assisted recombination.     

基于有限时间干扰观测器的改进模型水下机器人自适应鲁棒容错控制

针对无人水下机器人（unmanned underwater vehicle ,UUV）工作中存在的执行器故障,在系统不确定性与外界干扰下,提出一种基于有限时间扰动观测器（finite time disturbance observer ,FTDO）,并结合改进模型的自适应鲁棒容错控制方法。一方面,FTDO能在有限时间内对外界环境干扰进行估计;另一方面利用滑模控制加上径向基神经网络（Radial Basis Function Neyral Network,RBF） 的万能逼近特性,建立带有执行器故障的输入补偿;其中改进模型的引入解决了系统不确定性导致的输入饱和,提高了稳定性与鲁棒性;其次采用一种新型的双幂趋近律使滑模量在更短时间收敛到稳态误差界内;仿真与水池实验结果表明了所提方法相对于滑模控制有着更好的容错效果。     

浅析恩施硒产业发展的现状和机遇

介绍了恩施州硒产业发展的总体概况,分析了制约恩施硒产业发展的因素,指出了恩施州硒产业发展的机遇。     

宁夏房地产业存在的问题及对策

通过对宁夏房地产业现状以及存在问题进行的阐释,提出了解决问题的合理对策:切实减少各项不合理收费,降低成本,促进住宅价格合理回归;以中低收入阶层为重点,加大经济适用住房开发规模,发挥政府宏观调节作用。     

新疆绿色食品产业发展存在的问题及其对策

介绍了新疆绿色食品的发展特点,分析了目前存在的问题,并提出了相应的发展对策。     

A continuation principle for a class of periodically perturbed autonomoussystems

The paper deals with a T ‐periodically perturbed autonomous system in ℝⁿ of the form ((PS)) with ε > 0 small. The main goal of the paper is to provide conditions ensuring the existence of T ‐periodic solutions to (PS) belonging to a given open set W ⊂ C ([0, T ],ℝⁿ ). This problem is considered in the case when the boundary ∂W of W contains at most a finite number of nondegenerate T ‐periodic solutions of the autonomous system = ϕ (x). The starting point of our approach is the following property due to Malkin: if for any T ‐periodic limit cycle x 0 of = ϕ (x) belonging to ∂W the so‐called bifurcation function f (θ), θ ∈ [0, T ], associated to x₀, see (1.11), satisfies the condition f(0) ≠ 0 then the integral operator does not have fixed points on ∂W for all ε > 0 sufficiently small. By means of the Malkin's bifurcation function we then establish a formula to evaluate the Leray–Schauder topological degree of I – Q_ε on W. This formula permits to state existence results that generalize or improve several results of the existing literature. In particular, we extend a continuation principle due to Capietto, Mawhin and Zanolin where it is assumed that ∂W does not contain any T ‐periodic solutions of the unperturbed system. Moreover, we obtain generalizations or improvements of some existence results due to Malkin and Loud. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)