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11.
针对温室大棚的温湿度采集,提出了一种无线远程系统设计方案,介绍了系统结构和软硬件设计.系统以HT46R24单片机为节点控制核心,采用了数字式微型智能传感器SHT71,通过GSM网络与上位机进行无线数据通信.当温湿度出现异常时,启动语音报警功能,控制通风装置进行环境温湿度调节.上位机软件采用VB6.0编写,实现了与温湿度采集节点的数据通信以及对采集到的数据进行处理、储存、分析等操作.实验表明,系统运行稳定,具有很好的环境适应性. 相似文献
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以1,8-萘二甲酸酐和2-硝基-4-甲氧基苯胺为原料,用水作为溶剂合成了C.I.分散黄71.其总收率可达到88%,高效液相色谱含量可达到99%.得到的产品经应用测试达到国内外同行水平. 相似文献
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目的 对辽宁省2017-2019年肠道病毒71型(enterovirus type,EV71)灭活疫苗上市后疑似预防接种异常反应(adverse event following immunization,AEFI)监测数据进行分析,评价其预防接种安全性.方法 收集中国免疫规划信息管理系统中EV71 疫苗AEFI 监测数... 相似文献
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热轧高强度重轨钢的珠光体团块尺寸和层片间距以及钢轨表面脱碳层深度对钢轨在磨损和滚动接触疲劳条件下的使用性能具有重要影响.在邯钢采用SMS Meer万能机组轧制100 m定尺超长轨的设备工艺条件下,为了制定合理的U71Mn钢坯加热制度、细化珠光体组织和控制表面脱碳层深度,在实验室进行了加热工艺参数对U71Mn钢轨钢奥氏体晶粒尺寸和脱碳层深度的影响规律的实验研究.实验结果表明:U71Mn钢坯在加热温度升至1050~1150℃而均热时间为35min时,奥氏体晶粒尺寸和脱碳层深度开始有明显增长的趋势,奥氏体晶粒尺寸在120~160μm但比较均匀,有效脱碳层深度增加到0.42~0.61mm;当加热温度升高到1200~1250℃时,奥氏体晶粒尺寸超过180μm并随着保温时间的延长出现显著的不均匀长大,有效脱碳层深度增加到0.81~0.90mm.根据上述实验数据,对邯钢U71Mn钢加热工艺规程提出了优化参数,使热轧钢轨的珠光体组织、力学性能和脱碳层深度满足了国家标准和铁道部标准的要求. 相似文献
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Jinu Park Sang-Bum Kim Jae-Mok Ha Myung-Soo Kim Hong-Soo Park Hyun-Sik Hahm 《Korean Journal of Chemical Engineering》2001,18(4):468-474
The crystallization of the [Ga]-MFI was investigated as a function of synthesis time under atmospheric pressure. The molar
composition of the reactants was 100SiO2-Ga2O3-llNa2O-llTPABr-3500H2O. The crystallinity of the [Ga]-MFT was examined by using several analytical instruments, such as XRD, XPS, XRF, FT-IR, solid-statemas-NMR, DTG/DTA, and SEM. The [Ga]-MFI was successfully synthesized under atmospheric pressure at 97 ‡C in 72 h. It was found that
the nucleation of the [Ga]-MFI took a quite long time, but the crystallization took place very fast. It is supposed that nucleation
is the rate-controlling step in the [Ga]-MFI synthesis under atmospheric pressure. Consequently, if the induction period of
the nucleation can be shortened, it would be possible to synthesize the [Ga]-MFI commercially under atmospheric pressure. 相似文献
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FD-3025型γ定向辐射仪是目前我国铀矿山先进的γ定向辐射物探仪器,文章对FD-3025型γ定向辐射仪在仪器本底、补偿系数、换算系数、Th/U、Ra-U平衡以及氡子体方面对仪器的测量误差影响进行了详细分析,并提出了减少误差的方法与建议. 相似文献
20.
TRA86 removed the deductibility of state and local sales taxes from U.S. personal income taxes. This effectively increased the price to state governments of sales tax revenue relative to income tax revenues. This implies that state reliance on income taxes relative to sales taxes should have increased after TRA86 was implemented. Leading public finance economists investigated this in the period shortly following the reform and invariably found that the predicted substitution of income for sales taxes did not take place. In fact, several studies noted that state dependence on the sales tax increased relative to income taxes – hence the Sales Tax Puzzle. Several experts tried to rationalize their non-findings. These rationalizations are unconvincing. This paper asserts that the puzzle may be resolved in two different ways. The first, seemingly trivial, is that the analysis must incorporate sufficient time so as to allow for relatively complex adjustments. Our contributions here are to anchor this obvious point with a theoretical model related to earlier work of the authors, and an explicit empirical examination of the lag structures of individual states reactions to the comprehensive tax reform. The second demonstrates that the analysis must take into account regional shifts that were taking place in the U.S. during this period. When such compositional shifts involving political and deductibility patterns are explicitly introduced into the model, the paradoxical findings are resolved both in the long and in the short run. Our contribution here is a demonstration that the use of detailed state-level data, unlike any of the earlier work in this area, allows for the inclusion in the analysis of inter-regional shifts in various parameters. An additional contribution is the explicit use and emphasis of the propensity to itemize as an independent variable. The use of this variable ties this area of analysis of post tax reform behavior into a hitherto untapped strand of public-finance literature. The variable is both theoretically interesting, and proves to have experienced compositional shift patterns which help resolve the sales-tax puzzle paradox. 相似文献