中国蕨类植物孢子形态的研究Ⅲ.金星蕨科1.毛蕨属

利用扫描电镜对中国产毛蕨属51种植物孢子形态进行了研究。结果表明：该属孢子为单裂缝，两侧对称，极面观为椭圆形，赤道面观为肾形，由周壁形成表面纹饰。表面纹饰可分为3种类型：(1)周壁具流苏状的翅状纹饰，表面有突起或穿孔，有19种属于此类型；(2)鸡冠状纹饰，有11种属于此类型；(3)刺状纹饰，有10种属于此类型。另外有11种具有上述纹饰的混合纹饰，被认为是中间类型。孢子的形态特征可作为该属的分类学和孢粉学研究的资料。     

Barrier function-based nonsingular prescribed performance terminal sliding mode tracker for under-actuated nonlinear systems: Experimental study

In this paper, an adaptive concave barrier function scheme coupled with the non-singular terminal sliding mode control technique is proposed for finite-time tracking control of the under-actuated nonlinear system in the existence of model uncertainty, external disturbance and input saturation. Firstly, the dynamical equation of under-actuated nonlinear n-order system is expressed under model uncertainty, external disturbance and input saturation. Secondly, for the improvement of stability performance of the system in the existence of input saturation, a compensation system is designed to overcome the constraint on the control input. Afterward, the tracking errors between actual states of the system and differentiable reference signals are defined and the sliding surface based on the defined tracking errors is presented. Then, for gaining the better transient and steady-state performance of the closed-loop system, the prescribed performance control scheme is adopted. Based on this method, the transformed prescribed form of the previous determined sliding surface is obtained to ensure that the sliding surface can reach to a predefined region. Afterward, for assurance of the finite-time reachability of transformed sliding surface, the nonsingular terminal sliding surface is recommended. In addition, for the compensation of the model uncertainty and external disturbance existed in the system, the adaptive-based concave barrier function technique is used to estimate the unknown bounds of uncertainty and exterior disturbance. Finally, for demonstration of the proposed control method, the simulations and experimental implementation are done on the air levitation system.     

基于OLI影像的环渤海湾不透水面提取及空间格局分析

不透水面的分布规模、空间格局和变化是影响区域生态系统和环境变化的重要指标。Landsat 8卫星的成功发射使得基于Landsat系列遥感影像的陆地生态环境监测及其科学研究得以延续。本研究以该卫星搭载的陆地成像仪(OLI)影像为遥感数据源,基于植被-不透水面-土壤(V-I-S)模型,采用最小噪声分离法(MNF)和支持向量机(SVM)相结合的方法实现地表信息遥感影像分类,并提取高反照和低反照覆盖初步提取不透水面,利用遥感指数去除水体、阴影等干扰物后,得到研究区不透水面的分布现状,在此基础上分析其空间格局。结果表明：相较于TM影像,OLI影像辐射分辨率提高为16bit,其波段范围普遍变窄,影像经大气校正后色彩丰富度提高,其不透水面提取精度较高;2013年,环渤海湾海岸带不透水面比例达到16.74%,其空间分布集中于城市中心城区和临港产业区;岸线向陆10km的海岸带区域和岸线外围填海区的不透水面面积达到1 794.30km²;与历史时期TM遥感影像提取结果相比,环渤海湾不透水面分布的趋海化现象明显,不透水面斑块聚集程度增加。     

大都市功能区块视角下的热岛影响因素空间分异

针对以往热岛影响因素研究中缺乏因子综合作用及作用程度空间异质性分析的现状,本文以大都市北京为研究区,利用兴趣点（POI）数据划分承载不同人类活动的用地功能区块,结合地理探测器探究在市域整体及不同用地功能区块中植被、水体、不透水面及社会经济要素等多维因素对地表温度的影响（单因子作用与因子交互作用）。结果表明：①各单因子、因子交互作用对于地表温度的影响程度在北京市14类用地功能区块中存在空间分异。单因子探测表明整体上植被对温度的影响力高达72.3%,其作用程度与社会经济因素作用程度的差距在人类活动较为频繁的区块显著缩小;②因子交互作用探测显示两因子交互作用对温度的影响远大于单因子作用效果,整体水平上植被与人口交互作用是控制温度分异的主导因子,解释力达到78.9%,而在包含商业服务或公共管理服务的区块植被与人口交互作用均为影响温度分异的主导因素,包含工业的区块则为不透水与经济水平、植被交互作用为主导,且50 %区块内因子交互作用存在非线性增强现象。③根据风险探测识别出不同功能区块高温风险区特征,商业服务区块、公共管理与商业服务混合（公-商）区块为城市高温风险较高的区域。基于用地功能区块的地理探测器模型对地表温度空间分异的解释优于市域水平的全局模型,可以较好地量化各因素在不同空间位置上对地表温度的影响,为制定分区域有针对性的城市热岛效应缓解策略提供参考。     

太湖流域城镇绿地系统水生态服务功能研究

绿地系统是太湖流域城镇中主要的自然组成部分,绿地系统除具有净化空气、消除噪声、以及提供观赏和娱乐的功能外,在城镇生态系统中还具有重要的水生态服务功能,即绿地系统可以通过减少地表径流,以及吸收径流中的污染物质,达到调节水分、净化水质的目的。本研究基于太湖流域遥感解译的绿地系统,依据修正后的SCS(Soil Conservation Service)经验模型和相应的逐日降雨量计算出太湖流域不同城市绿地系统减少的地表径流量和去除污染物量。研究表明,太湖流域绿地系统在2008年截留降水量4.79×108m3,去除COD1916.21t、总氮946.10t、总磷34.49t和氨氮25.87t。     

土钉墙内部稳定性分析禁忌搜索算法

基于边坡极限平衡的简化Bishop法,考虑土钉的加固作用,推导了土钉墙安全系数计算公式;然后利用禁忌搜索算法(TSA)对北京某大厦基坑土钉支护结构最危险滑动面的位置及相应最小安全系数进行了搜索.计算结果表明:TSA法的搜索性能要优于简单遗传算法且本文土钉墙简化Bishop法克服了瑞典条分法的不足,具有较高的计算精度.     

波导管与法兰盘电铸连接工艺的研究与应用

在波导管两端面上连接法兰盘时通常采取的是银钎焊工艺,由于银钎焊是一种高温连接从而带来了很多弊病。本文在充分论证试验后,实现了将波导管与法兰盘直接电铸成一体的新工艺技术。同时,本文还阐述了在实施该工艺过程中是如何较好地解决电铸模芯材料、连接强度、致密与韧性三大关键性技术。     

一种改进的遥感热惯量模型初探

本文改进了遥感热惯量模型 ,考虑到植被因素的影响 ,在植被覆盖区 ,使用双层模型中的土壤热能量平衡方程 ,同时在热传导方程的边界条件中引进显热通量和潜热通量 ,使热惯量模型的应用范围从裸土扩展到植被覆盖区 .通过顺义地区的MODIS影像数据和同步野外测量数据对此模型进行验证 ,所获得的热惯量值与实测热惯量值进行比较 ,结果表明改进模型的实用性和可行性 .     

外来入侵物种互花米草(Spartina alterniflora)及凤眼莲(Eichhornia crassipes)的遥感监测研究进展

外来物种的入侵给生态系统带来了许多正面的和负面的影响。并已成为当前学术界关注的热点问题之一。为了有效地管理以及合理地开发利用外来入侵物种,变害为利,需要对其种群的空间分布和动态变化进行监测。然而由于沿海滩涂和水体表面特殊的自然地理环境,使得传统的实地调查较为困难。3S技术是近年来发展起来的,从较大尺度定量研究滩涂植被互花米草（Spartina altemiflora）或水生植被凤眼莲（Eichhornia crassipes）的一种有效手段。研究人员通过收集不同时相的遥感影像．运用遥感处理软件对其进行分类解译,并结合GPS的野外核实修正,最后在GIS中对解译结果进行数据合成,即可统计出滩涂及水生植被的空间分布及动态变化。国内外的研究表明．3S技术可应用于外来入侵物种的动态监测,进而为人侵物种的控制与管理提供科学依据。但由于海岸带地区空间尺度相对较小。水生植物的空间分布变化比较剧烈,植被群落交错地带存在着混合像元,使得这一方法的分类精度具有一定的局限性,还需要进一步的研究和改进。     

Characterization of low viscosity polymer solutions for microchip electrophoresis of non-denatured proteins on plastic chips

In this paper, we study characteristics of polymers (methylcellulose, hypromellose ((hydroxypropyl)methyl cellulose), poly(vinylpyrrolidone), and poly(vinyl alcohol)) with different chemical structures for microchip electrophoresis of non-denatured protein samples in a plastic microchip made of poly(methyl methacrylate) (PMMA). Coating efficiency of these polymers for controlling protein adsorption onto the channel surface of the plastic microchip, wettability of the PMMA surface, and electroosmotic flow in the PMMA microchannels in the presence of these polymers were compared. Also relative electrophoretic mobility of protein samples in solutions of these polymers was studied. We showed that when using low polymer concentrations (lower than the polymer entanglement point) where the sieving effect is substantially negligible, the interaction of the samples with the polymer affected the electrophoretic mobility of the samples. This effect can be used for achieving better resolution in microchip electrophoresis of protein samples.     

地铁施工对周围环境影响的监测研究

为了更好地研究解决城市隧道施工给邻近环境带来的影响,特别是石家庄地区地铁隧道开始兴建,保证地铁安全施工是目前的首要任务。本文以石家庄地区地铁隧道施工为具体研究对象,对本地区的地表沉降、地下管线变形和周围建筑物监测情况进行分析,提出了有效的监测施工方案,为石家庄后期的地铁隧道监测提供理论支撑。     

电信服务业员工的情绪劳动与生活满意度——心理解脱的调节作用

通过对332名电信营业厅服务岗位员工进行问卷调查,探讨员工工作中的心理解脱在情绪劳动与倦怠、情绪劳动与生活满意度的关系,以及在他们关系中的调节作用。结果发现,心理解脱不仅调节表层动作对生活满意度的负作用,而且调节倦怠对生活满意度的预测作用。当员工在下班之后,经历高的心理解脱时,表层动作和倦怠对生活满意度的负面影响作用将会降低。研究结果有助于解释努力-恢复理论中,工作压力可以通过远离工作任务的方式,重新获得心理资源,促进这些因素在家庭界面的积极作用,提高个人幸福感和心理健康水平。     

基于地形复杂度的建设用地适宜性评价——以甘肃省天水市为例

地形条件是评价城乡建设用地必需考虑的主要因素。以甘肃省天水市为例,应用ArcGIS和DEM模型分析海拔高度、坡度和地表破碎度3个地形因子综合的地形复杂度。结果表明:地表破碎度代表了地形变化上的一维独立属性,3个地形因子综合的地形复杂度比海拔高度和坡度2个因子组合的地形复杂度更好地反映地形起伏变化的信息。以乡镇为单元进行建设用地适宜性的评价,天水市非常适宜、较为适宜、适宜、临界适宜和不适宜5级土地的比重分别为9.7%、24.6%、19.3%、21.9%和24.5%。以村级尺度来评价,丘陵山区地形变化大致归为6种基本类型:塬峁型、上偏型、正态型、下偏型、河谷盆地形和复杂变化型。非常适宜、较为适宜的建设用地多分布在下偏型、河谷盆地形,结果与人类长期以来实际选择的建设用地高度一致。在地形复杂的天水市,实行"组团发展"有利于城市空间的扩张。     

On the uncertain variable structure systems with bounded controllers

In this paper, we propose a method to estimate the asymptotic stability region (ASR) of uncertain variable structure systems with bounded controllers. Using linear matrix inequalities (LMIs) we estimate the ASR and we show the exponential stability of the closed-loop control system in the estimated ASR. We also give simple LMI-based algorithms for estimating the ASR and designing a switching surface which will make the estimated ASR big. Finally, we give numerical examples in order to show that our method can be better than the previous results for a certain class of uncertain variable structure systems with bounded controllers.     

NATSUM: Narrative abstractive summarization through cross-document timeline generation

A new approach to narrative abstractive summarization (NATSUM) is presented in this paper. NATSUM is centered on generating a narrative chronologically ordered summary about a target entity from several news documents related to the same topic. To achieve this, first, our system creates a cross-document timeline where a time point contains all the event mentions that refer to the same event. This timeline is enriched with all the arguments of the events that are extracted from different documents. Secondly, using natural language generation techniques, one sentence for each event is produced using the arguments involved in the event. Specifically, a hybrid surface realization approach is used, based on over-generation and ranking techniques. The evaluation demonstrates that NATSUM performed better than extractive summarization approaches and competitive abstractive baselines, improving the F1-measure at least by 50%, when a real scenario is simulated.     

Fractional order sliding mode control of a pneumatic position servo system

Gas flow has fractional order dynamics; therefore, it is reasonable to assume that the pneumatic systems with a proportional valve to regulate gas flow have fractional order dynamics as well. There is a hypothesis that the fractional order control has better control performance for this inherent fractional order system, although the model used for fractional controller design is integer order. To test this hypothesis, a fractional order sliding mode controller is proposed to control the pneumatic position servo system, which is based on the exponential reaching law. In this method, the fractional order derivative is introduced into the sliding mode surface. The stability of the controller is proven using Lyapunov theorem. Since the pressure sensor is not required, the control system configuration is simple and inexpensive. The experimental results presented indicate the proposed method has better control performance than the fractional order proportional integral derivative (FPID) controller and some conventional integral order control methods. Points to be noticed here are that the fractional order sliding mode control is superior to the integral order sliding mode counterpart, and the FPID is superior to the corresponding integral order PID, both with optimal parameters. Among all the methods compared, the proposed method achieves the highest tracking accuracy. Moreover, the proposed controller has less chattering in the manipulated variable, the energy consumption of the controller is therefore substantially reduced.     

我国草原恢复与保护的问题与对策

我国草原总面积为392.8万平方公里,约占国土面积的40.9%,是国家生态安全的重要绿色屏障,也是农牧民赖以生存的主要生产资料。然而,自20世纪80年代开始,我国草原发生了大面积、不同程度的退化。迄今,"局部好转、整体恶化"的态势没有得到根本扭转,这已成为制约我国生态文明建设和社会经济发展的主要瓶颈。文章分析了我国草原恢复与保护的现状及存在的问题,提出草原恢复与可持续管理的对策,旨在为我国草原的恢复、保护和可持续利用提供参考。     

Robust adaptive multistage anti-windup dynamic surface control for dynamic positioning ships with mismatched disturbance

In this paper, a novel robust adaptive multistage anti-windup control strategy is developed for dynamic positioning ships in presence of input constraint, mismatched disturbance and external disturbance. Based on dynamic surface control technique, a composite control law, where both mismatched and matched disturbances are compensated, is established to stabilize the system without the requirement of solving any partial differential equations. In particularly, the mismatched disturbance caused by the model transformation is analyzed firstly and the better steady performance is achieved. In addition, a novel multistage anti-windup control based on anticipatory activation compensation is constructed to handle the input constraint while the transient performance is improved significantly. Moreover, the stability of the closed-loop system is proven via Lyapunov technique rigorously, and the tracking error can be forced into an arbitrarily small neighborhood around zero. Finally, simulations with comparisons demonstrate the effectiveness of the proposed method.     

MOZART-2对欧洲地区对流层臭氧的模拟研究

本文运用新建立的全球三维大气化学模式MOZART-2与全球大气环流模式CAM2的离线耦合模式系统对欧洲地区地面和对流层臭氧浓度进行了数值模拟研究。模式的模拟结果分别与欧洲两个站点的地面观测资料和四个站点的臭氧探空观测资料进行了对比分析研究。通过将模拟结果与欧洲地面观测资料的对比分析表明，该模式系统除了对德国Hohenpeissenberg地面观测站臭氧浓度略微高估和荷兰Kollumerwaard地面观测站臭氧浓度有些低估外,能基本上反映所在地区地面臭氧和一氧化碳浓度的季节变化特征。通过将模拟结果与德国Lindenberg和芬兰Sodankyla两个站点臭氧探空观测资料的对比分析表明，该模式系统能较为成功地再现对流层臭氧浓度的大小和垂直梯度特征，特别是能较为准确地模拟出两站点秋季对流层中部臭氧浓度的大小。另外，该模式系统也能够基本上反映该地区对流层臭氧浓度的季节变化和纬度变化特征，对德国Hohenpeissenberg站点和挪威Nyalesund站点对流层上层臭氧浓度的模拟结果更接近于观测值。本研究结果表明，该模式系统对欧洲地区对流层臭氧浓度的大小和分布具有良好的模拟性能，这为进一步运用该模式系统探讨欧洲地区的污染排放物对亚洲的输送问题提供了科学的依据。     

Reduced-order K-filters-based event-triggered adaptive command filtered tracking control for stochastic constrained nonlinear systems

To ensure better performance and simultaneously save resources, an event-triggered adaptive command filtered dynamic surface control (ACFDSC) method for uncertain stochastic nonstrict-feedback nonlinear systems with dynamic output constraints and prescribed performance is designed in this article. Firstly, with the help of reduced-order K-filters, linearly parameterized neural networks and specific coordinate transformation technique, the unmeasurable states, nonlinearities, two types of unmodeled dynamics and output constraints are dealt with respectively. Then, an event-triggered ACFDSC strategy is proposed to ensure that the tracking error reaches a specific bound within a finite time. By introducing the compensated signal into the complete Lyapunov function, and with the assistance of the compact set defined in the stability analysis, all signals are strictly demonstrated to be semi-globally uniformly ultimately bounded. The simulation results verify the effectiveness of the proposed method.