检索结果-南通市图书馆

The products obtained during the thermal decomposition of ammonium meta-vanadate depend on the configuration of the container, the mass of the sample, the heating rate and the composition of the carrier gas. The decomposition in an uncapped container produced (NH4)2V4O11, NH4V3O8, and V2O5 as the apparent stable products while the products in a capped container were NH4V3O8, and V2Ox where x was between 4 and 5. These differences are attributed to the different amounts of the evolved gases in the cell. EGA-FTIR clearly established that the reduced final product in the capped cell resulted from a reaction between NH3 and the V2O5 formed during the decomposition. A pre-equilibrium kinetics model where the rate of the reverse reaction depends on the partial pressure of the gaseous products in the cell could explain the different reaction intermediates. This model provides a possible explanation for the different apparent activation energies that have been reported for the thermal decomposition of other compounds where a reversible step could occur in the decomposition mechanism.

关键词： Ammonium Meta-Vanadate Thermal Decomposition Kinetics Activation Energy

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

主妇也有出头天

引用

疯狂英语（新悦读） 2015年第5期 31-34页

作者： lori Weiss 铖铖

"家庭主妇"通常给人的形象是庸庸碌碌、不修边幅、无甚才干,与干练、光鲜、优雅的职业女性大相径庭。然而,偏偏有些主妇却能从人们眼里的"绝望"生活中发现商机,开创自己的事业,家庭与事业都能兼得。她们是怎样做到的呢?

关键词：职业女性布雷利柯尔斯滕 decided think talking doing 创业成功 factory

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Plant Community Development in a Dryland CREP in Northeastern Oregon

引用

American Journal of Plant Sciences 2011年第6期2卷 744-752页

作者： John D. Williams Heidi M. Hartman lori M. Spencer James O. Loiland USDA Agricultural Research Service Columbia Plateau Conservation Research Center Pendleton USA Umatilla Soil & Water Conservation District Pendleton USA Department Environmental Science and Regional Planning Washington State University Tri-Cities Richland USA District Conservationist (USDA-NRCS) Dillingham Field Office Dillingham USA

Riparian areas in dryland crop regions of the Intermountain Pacific Northwest have largely been converted to cropland or pasture during the last 140 years. Some formerly cultivated floodplains have become difficult to farm;enrollment of these lands into conservation programs provides the opportunity to use them as wildlife habitat and as buffer areas near streams. Our objective was to evaluate plant community development on an USDA Conservation Reserve Enhan- cement Program site in northeastern Oregon from when the plant was planted in 1999 through 2008. The research was designed as a descriptive study. We established permanent line-transects to quantify vegetation establishment and changes in species composition through time. We collected data in 2000-2001 and 2007-2008. Vegetation cover in 2000-2001 was 100%, dominated by tall wheatgrass. Living plant material cover decreased from 98% in 2000-2001 to 33% in 2007 and 68% in 2008;dead plant residue significantly increased and tall wheatgrass cover decreased. Native species were present in similar percentages from 2000 to 2008, although there was a shift from target to nontarget species. The 1999 seeding can be judged a success because of the ground cover provided and the establishment of one target species, tall wheatgrass. However, the increased ratio of dead to living plant material and shift to non-target annual weed species suggests that more active management (i.e., fire, grazing, or mowing) of the tall wheatgrass stand is needed to maintain its productivity and/or a healthy mix of multiple species.

关键词： Conservation Buffers Riparian Management Weed Control Plant Community

来源：

维普期刊数据库评论