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421.
介绍了旅客列车报警系统的组成.给出了基于MSP430单片机并结合新型的高性能低功耗的收发一体的CC1100芯片,设计报警节点;利用BCH(15,7)编码保证无线通信的可靠;并用间断工作的方式进一步降低了功耗.通过实验证明,设计运行稳定可靠,并满足低功耗长时间工作的要求. 相似文献
422.
乌苏里江唇耗氧率和窒息点的初步研究 总被引:2,自引:0,他引:2
进行不同温度和不同规格人工养殖的乌苏里江唇(Hemibarbus labeo)耗氧量(MO2)、耗氧率(WO2)和窒息点(SO2)的初步测定。结果表明:水温16~28℃范围内,随着水温的升高,耗氧率、耗氧量和窒息点都表现出增大的变化趋势。温度和耗氧率的回归方程:1龄鱼体重11 g的为WO2=0.0142T-0.0863(R2=0.9617),2龄鱼体重60 g的为WO2=0.0138T-0.1121(R2=0.97);温度和窒息点的回归方程:1龄鱼体重8 g的为SO2=0.0298T-0.1891(R2=0.977 8),2龄鱼体重40 g的为SO2=0.048 8T-0.402 5(R2=0.999 7)。体重20~100 g范围内,水温25℃时,随着体重规格的增大,耗氧量逐渐升高,耗氧率逐渐减小。体重和耗氧率的回归方程为WO2=0.7825W-0.2898(R2=0.947 4),体重和耗氧量的回归方程为MO2=0.7837W0.7097(R2=0.991 6)。唇鱼的昼夜耗氧率(水温25℃,体重72 g)有一定的变化趋势,早间4~10时耗氧率较高,平均在0.332±0.046 mg/(g.h),午间11~19时中等,在0.287±0.030 mg/(g.h),晚间20~3时较低,在0.251±0.029 mg/(g.h)。 相似文献
423.
This study deals with the hydrochemical state and management measures for the intermediate culturepond for Chinese prawn (Penaeus orientalis) juveniles. The test result showed that the intermediate cultureof Chinese prawn juvenile can be advanced to around March 20 in the Shanghai area if they are culturedin ponds in simple greenhouses of plastic knitting cloth.The density of juveniles introduced was about35 million per hectare, survival was up to 55%. 相似文献
424.
随着文化创意产业在世界范围内的崛起,城市文化职能和全球文化城市成为城市网络研究的新兴视角。借助“大麦网”数据,基于空间分析和岭回归方法,揭示基于文化演出消费活动的中国城市网络空间结构与影响因素,对现有城市网络研究形成补充。研究表明:①文化巡回演出的城市网络呈现出中国城市网络中常见的“菱形结构”,但是向二、三线城市渗透的趋势较为明显,体现了不同级别城市本地文化生产能力的差异以及文化演出边际收益递增的特点;②中西部省会城市在城市网络中的影响力表现出明显的上升,而东部沿海地区核心城市的影响力则出现一定程度的下降,反映出中国不同地区演出市场发育程度以及区域中心城市在对外文化联系中地位的差异;③不同类型文化演出在空间分布和网络结构上同样存在较为明显的差异,反映出其市场结构和盈利模式的差异以及城市地方文化消费特征的影响;④文化教育发展水平、地方政府投入、城市总体经济发展和消费水平以及对外开放程度是影响中国文化演出消费城市网络空间格局的重要因素,反映出文化演出消费的独特性。 相似文献
425.
Wang Changjian Wang Fei Zhang Xinlin Wang Yang Su Yongxian Ye Yuyao Wu Qitao Zhang Hong’ou 《地理学报(英文版)》2022,32(3):401-420
Journal of Geographical Sciences - Guangdong Province, as one of China’s fast-developing regions, an important manufacturing base, and one of the national first round low-carbon pilots, still... 相似文献
426.
427.
Gert Spaargaren 《Global Environmental Change》2011,21(3):813-822
Within the environmental social sciences, theories of practices are used by an increasing number of authors to analyze the greening of consumption in the new, global order of reflexive modernity. The use of practices as key methodological units for research and governance is suggested as a way to avoid the pitfalls of the individualist and systemic paradigms that dominated the field of sustainable consumption studies for some decades. With the help of practice theory, environmental governance can be renewed in three particular ways: First, the role and responsibilities (not) to be assigned to individual citizen-consumers in environmental change can be specified. Secondly, objects, technologies and infrastructures can be recognized for their crucial contribution to climate governance without lapsing into technological determinism. Third, the cultural framing of sustainability can be enriched by looking into the forms of excitement generated in shared practices of sustainable consumption. We conclude by discussing the need to investigate the globalization of practices from a post-national perspective in both science and policy. 相似文献
428.
Zhongming Zheng Jing Lv Kaihong Lu Chunhua Jin Jinyong Zhu Xiasong Liu 《洁净——土壤、空气、水》2011,39(6):566-571
A mesocosm experiment was conducted for 32 days in an eutrophic pond to study the effects of the bioturbation of the freshwater snail, Bellamya aeruginosa, on the benthic environment and to further understand cycling of organic carbon in water containing algal blooms. Chlorophyll‐a (chl‐a), phaeopigment, and organic matter contents of sediment, sediment oxygen consumption (SOC), and dissolved organic carbon (DOC) fluxes were determined on day 1, 16, and 32, respectively. The SOC decreased on day 16 and increased on day 32 significantly with the increase in snail density. DOC fluxes showed a net sediment uptake in all enclosures throughout the experiment. DOC fluxes in the high and mid density treatments were lower than those of the control. The concentrations of chl‐a and phaeopigment in the sediment increased significantly with snail density, indicating that the presence of snails reduced the biomass of phytoplankton. The results suggest that freshwater snails, B. aeruginosa, could influence the algal biomass (chl‐a) of small water bodies by their bioturbation effects on sediment characteristics and the fluxes of organic carbon. 相似文献
429.
Though the concept of sustainable development originally included a clear social mandate, for two decades this human dimension has been neglected amidst abbreviated references to sustainability that have focused on bio-physical environmental issues, or been subsumed within a discourse that conflated ‘development’ and ‘economic growth’. The widespread failure of this approach to generate meaningful change has led to renewed interest in the concept of ‘social sustainability’ and aspects thereof. A review of the literature suggests, however, that it is a concept in chaos, and we argue that this severely compromises its importance and utility. The purpose of this paper is to examine this diverse literature so as to clarify what might be meant by the term social sustainability and highlight different ways in which it contributes to sustainable development more generally. We present a threefold schema comprising: (a) ‘development sustainability’ addressing basic needs, the creation of social capital, justice and so on; (b) ‘bridge sustainability’ concerning changes in behaviour so as to achieve bio-physical environmental goals and; (c) ‘maintenance sustainability’ referring to the preservation - or what can be sustained - of socio-cultural characteristics in the face of change, and the ways in which people actively embrace or resist those changes. We use this tripartite of social sustainabilities to explore ways in which contradictions and complements between them impede or promote sustainable development, and draw upon housing in urban areas as a means of explicating these ideas. 相似文献
430.
An unsustainable state: Contrasting food practices and state policies in the Czech Republic 总被引:1,自引:0,他引:1
Petr Jehli?ka 《Geoforum》2011,42(3):362-372
This paper brings together consideration of food policies and practices and of post-socialist transition to raise neglected questions about means of nurturing more sustainable food systems in the developed world. The last three decades have been marked by the growing salience of food as a political and scholarly concern. While market-based alternative food systems have been heralded for their potential to promote environmental sustainability, the benefits of non-market practices such as household food self-provisioning and barter have been assumed rather than being the focus of research. In the western context, both types of food consumption have positive connotations. Although food self-provisioning in European post-socialist societies is a more wide-spread practice than in western societies, it has been on the periphery of research. The existing literature has conceptualised them as ‘coping strategies’ or as a legacy of irregular supply of goods in the state socialist era. Drawing on empirical research in the Czech Republic, we are proposing a novel approach to the phenomenon of household food production in post-socialist societies as a practice compliant with principles of sustainability. First, we highlight the large extent and social inclusivity of food self-provisioning in Czech society to demonstrate how post-socialist societies are a repository of a rich set of sustainability-promoting consumption practices in relation to food systems. Second, we show that international and domestic policy actors in these societies have ignored these alternative, socially inclusive and environmentally effective practices in favour of far less effective market-based sustainability oriented food policy initiatives. The paper promotes a more integrated view of non-market and market approaches in the pursuit of more sustainable food systems. 相似文献