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521.
湖北省节庆旅游开发研究 总被引:11,自引:0,他引:11
节庆旅游的开发在提高区域知名度、传播区域文化、塑造区域旅游品牌、促进区域对外经济合作、带动区域经济发展方面发挥重要作用。在对节庆旅游概念界定和湖北省节庆旅游概况分析的基础上,从精品打造、市场运作、分工协作、群众参与、营销等方面提出了湖北省节庆旅游开发的策略。 相似文献
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信息家电远程控制系统及其安全 总被引:3,自引:0,他引:3
利用蓝牙技术构建信息家电网络,通过Internet或PSTN(公共交换电话网)对信息家电实现远程控制。笔者给出了基于蓝牙技术的信息家电网络的组成,设计了基于PSTN的远程控制系统。系统采用单片机控制,用户可使用固定电话或手机,根据系统提供的语音提示对其进行远程控制。输入初始密码,由双音多频收号器接收密码,并由系统进行验证,只有正确输入密码,用户才有权对系统进行操作,且可连续对信息家电系统中多个设备实施远程控制。初始密码验证通过后,用户可以根据语音提示很方便地进行密码的设置和修改。通过设置密码和蓝牙技术的安全机制,提供了信息家电网络和远程控制系统的安全保障。 相似文献
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Antoine?O.H.C.?Leduc Maud?C.O.?Ferrari Jocelyn?M.?Kelly Grant?E.?BrownEmail author 《Chemoecology》2004,14(2):107-112
Summary. Recent studies have demonstrated that under
weakly acidic conditions (pH 6.0), many prey fishes, including
juvenile rainbow trout (Onchorhynchus mykiss), do not
exhibit overt antipredator responses to conspecific chemical
alarm cues. In laboratory trials, we investigated the potential
effects of reduced pH on the ability of hatchery reared, predator
naïve juvenile rainbow trout to acquire the recognition of
a novel predator (yellow perch, Perca flavenscens). Initially,
we exposed trout to the odour of a predatory yellow perch,
buffered to pH 6.0 (weakly acidic) or pH 7.0 (neutral) paired
with conspecific skin extracts (also buffered to pH 6.0 or 7.0)
or a distilled water control. Juvenile trout exhibited significant
increase in antipredator behaviour when exposed to neutral
skin extract (pH 7.0). When retested 48 hours later to perch
odour alone (pH 7.0), only trout initially conditioned with
neutral skin extracts (pairs with either neutral or acidic perch
odour) exhibited a learned recognition of perch odour as a
predator risk. Those initially exposed to weakly acidic skin
extract or the distilled water control did not show a learned
response to predator odour. These results demonstrate that the
ability to acquire the recognition of novel predators is
impaired under weakly acidic conditions, as would occur in
natural waterways affected by acidic precipitation. 相似文献
527.
Electric power generating plants that use coal were among the key targets of Title IV of the 1990 Clean Air Act. Under the
first phase of the act, 110 coal-fired electric power plants were required to reduce their sulfur dioxide emissions by 1995
and nitrogen oxide emissions by 1996. Phase 2 of the act requires even greater reduction of sulfur dioxide emissions by 2000
and nitrogen oxide emissions by 2008. This study examines whether the 107 targeted plants (three plants went off-line) have
achieved the desired sulfur dioxide and nitrogen oxide emission levels.
The analysis of sulfur dioxide is based on data from 1990, 1995, and 1999. The findings show that although sulfur oxide increased
by 3% from 1995 to 1999, it decreased by 45% over the 1990–1999 period at the firm level for the targeted firms. The findings
also indicate that the overall reduction in sulfur dioxide was achieved by utilizing low sulfur coal and by purchasing emission
allowances. So far as nitrogen oxides are concerned, there has been a reduction of 14% over the 1990–1999 period, of which
7% was achieved during the 1995–1999 period. An evaluation of emissions at the plant level indicates that several plants do
not meet the emissions level for sulfur dioxide or nitrogen oxides.
These results provide a mixed scorecard for reduction in emissions both for sulfur dioxide and nitrogen oxides. Even though
there is reduction in the emissions on an overall basis at the firm level, several plants that have not been able to reduce
emissions deserve special attention to meet the goals of the act in reducing emissions. 相似文献
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着重阐述了武汉市汽车排气污染现状及汽车污染物的产生 ,介绍了国内外控制汽车污染物排放的技术和措施 ,提出了武汉市汽车排气污染的发展趋势。 相似文献