CPU超频不可取

章从电脑系统的观点，阐述了CPU超频不可取的几点重要理由。     

Climate change versus land-use change—What affects the mountain landscapes more?

Land use and climate change are both strong drivers of landscape transformation. Using a representative valley of the Central Alps (Stubai Valley, Tyrol, Austria) we assess (1) the historical and likely future spatial patterns of land use/land cover (LULC), (2) the influence of temperature increase on the LULC distribution, and (3) the speed at which these changes will occur. Based on the historical landscape development and spatially explicit models, the effects of various land use and climate scenarios were modelled. Employing a pan-Alpine model, we were able to detect the temporal trajectory of spatial reforestation. The results show that land-use changes that already occurred during the last decades are responsible for the main future LULC changes (by secondary succession). Only an extreme land abandonment scenario and extreme climate scenarios (5 K temperature increase) would bring about similar changes in LULC distribution and expansion of the forested areas. While alpine grasslands, alpine pioneer formation and glaciers would shrink drastically, especially deciduous forests would spread. To a considerable degree, such changes might take place over the next 300 years. By contrast, the increase in forest areas triggered by temperature changes would be slower and longer termed (up to 700–800 years).The effects and intensity of land-use change in the investigated valley, that is comparable to many regions in the Alps, will be at least equally severe and responsible for transformation of the landscape as those of a projected temperature increase.     

基于时钟和地址的跳频序列的产生和性能分析

在一般跳频系统中，跳频序列是由递归算法产生的，如PN序列以及混沌序列、模糊序列等。本文介绍的基于时钟和地址的跳频序列提供了一种新的产生方法。这种序列是由长比特设备地址和不断变化的长比特时钟信息经过一系列运算而产生的，即基于时钟和地址和跳频序列，该序列具有理想的均匀频谱特性和很长的周期；序列线性跨距很长，不容易被智能干扰机干扰；序列的汉明相关特性也很好；这个特点在多址接入通信中非常有用。该序列另一个重要特征是硬件实现简单容易，事实上，这种序列巳成功应用于蓝牙跳频系统中。本文主要介绍这种跳频序列的设计产生过程，并对序列的各种性能进行分析。     

X波段高稳定相干频率源倍频-放大组件设计

本文介绍X波段高稳定相干频率源倍频－放大组件的设计方法和实验结果。为满足设计要求，对其电磁兼容性进行分析，给出了电磁兼容性设计和具体实施措施。     

基于YIG振荡器实现的X波段频率合成器

本文介绍了一种YIG(Yttrium Iron Garnet)振荡器的X波段频率合成器的设计方案，实验结果表明，该合成器性能稳定可靠。     

蓝牙跳频算法仿真和系统容量分析

本文讨论了Bluetooth（蓝牙）无线系统的跳频算法，并对其进行了计算机仿真；根据仿真结果，分析了Bluetooth的系统容量，并提出了提高系统容量的建议。     

一种新型的微波介质谐振器高次倍频器

将微波介质谐振器应用于阶跃管高次倍频器中,这是一种新的尝试.由此构成的微波高次倍频器,既具有微波集成高次倍频器体积小、重量轻、加工简单的特点,又具有微波同轴腔高次倍频器对相邻谐波抑制度高的优点.因而是一种在星、弹航天设备中非常有用的微波固态源部件.已研制成的C波段22次倍频器,集成在两块20×60×1mm的氧化铝陶瓷基片上,对相邻谐波的抑制,在-40℃～+70℃温度范围内优于-50dB.     

混频频率的最佳选择

本文推出一种简便的混频频率选择法,试图解决混频器的组合干扰问题.文中定义了组合波的干扰程度,并列表给出了不同中频频率的各阶组合波的相关信号及本振频率.     

Bottom-up design process of agri-environmental measures at a landscape scale: Evidence from case studies on biodiversity conservation and water protection

An Agri-environmental measure (AEM) is a payment to farmers to reduce environmental risks or to preserve cultivated landscapes. The single farm scale that is the basis for the AEM has often inhibited the achievement of the environmental goals since many biophysical processes (e.g. soil erosion, water pollution, biodiversity losses) occur at landscape scale. This creates a spatial scale mismatch between the implementation scale of the measures and the ecological processes controlling the target agri-environmental issues. In this paper, we propose how to address this spatial scale mismatch by analysing nine case studies of AEMs implementation at landscape scale concerning biodiversity conservation and water protection. The analysis highlights that the inclusion of the landscape scale in AEMs depends on the level of the involvement of the local stakeholders (SH) in the building process. When the authorities created the space for the SHs to participate in the defining process of AEMs, the inclusion of local knowledge led to the emergence of new landscape and site-specific AEMs which were not previously considered by the autorities. On the contrary, when the SHs were only allowed to choose among the AEMs predefined by the authorities, many site specificity and acceptance issues arose. The creation of space in Rural Development Programmes for collaborative, bottom-up and landscape scale AEMs and the overcoming of institutional constraints in the design of specific actions are the key ingredients for the successful adoption of measures and for enhancing their effectiveness. In this paper, we explore in depth what made these stories successful and provide a framework for the implementation of site-specific and landscape AEMs.     

多频道通信程控频率合成器

本文以大规模锁相环集成电路为中心,提出了一种可程控的频率合成技术。探索了多频道无线通信频率切换的方法,并给出了电路设计参数,图表以及微机接口的硬件和软件流程。有效地解决了多频道通讯中的程控频道切换的问题。