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111.
为了解决耦合线滤波器谐波抑制问题,提出了一种新的结构简单的平行耦合线带通滤波器.该滤波器由平行耦合线和开路枝节组成.首先基于耦合线带通滤波器的等效电路图,通过奇偶模理论得到设计方程,并设计了带通滤波器;分析了滤波器特性与电参数之间的关系;通过仿真优化得到了滤波器的物理尺寸;制备并测试了滤波器的S参数,仿真结果和测试结果基本一致.该滤波器具有结构简单、面积小等优点,并通过引入传输零点实现了较宽的阻带抑制和较好的选择性. 相似文献
112.
Geetanjali Yadav Leonard A. Fabiano Lindsay Soh Julie Zimmerman Ramkrishna Sen Warren D. Seider 《American Institute of Chemical Engineers》2021,67(1):e16992
Algae-to-biodiesel processes are hindered by high costs and low energy return on investment.1,2. Herein, three foci in research improve algae-to-biodiesel processes by: (1) reducing high installation and energy costs in the CO2 sequestration, cultivation, and harvesting stages; (2) improving oil extraction and biodiesel generation; and (3) increasing utilization of the proteins in lipid-extracted biomass (e.g., for animal feed), as well as the omega-3 fatty acids for nutraceuticals and food supplements. A process is introduced that uses carbon dioxide to aid in all three of these foci. CO2 is used first in the form of microbubbles to lyse algae cell walls, releasing triglyceride oils. CO2 also aids with transesterification of these triglycerides using methanol. At low temperatures (353.15–368.15 K) and intermediate pressures (5–10 MMPa), carbon dioxide causes methanol to dissolve partially in the triglyceride phase and triglyceride to dissolve partially in the methanol phase, increasing the transesterification reaction rate. Due to the nondestructive nature of these processes, other metabolites can also be harvested providing improvements in both mass and economic efficiency with an overall sharp reduction in the modeled price of biodiesel. 相似文献
113.
介绍了蛋白质、蛋白酶以及短肽类研究的一些传统方法和新兴方法。主要对分离、提纯、鉴定及分析方法的使用条件、适用范围、操作步骤、各自特点和应用价值作了简要阐述,并对有关方法进行了比较与评价。 相似文献
114.
William B. Zimmerman Mohammad Zandi H.C. Hemaka Bandulasena Václav Tesař D. James Gilmour Kezhen Ying 《Applied Energy》2011
This study was conducted to test the feasibility of growing microalgae on steel plant exhaust gas, generated from the combustion of offgases from steel processing, which has a high CO2 content. Two field trials of batch algal biomass growth, mediated by microbubble transfer processes in an airlift loop bioreactor showed only steady growth of biomass with 100% survival rate. The gas analysis of CO2 uptake in the 2200 L bioreactor showed a specific uptake rate of 0.1 g/L/h, an average 14% of the CO2 available in the exhaust gas with a 23% composition of CO2. This uptake led to a steady production of chlorophyll and total lipid constituency in the bioreactor, and an accelerating exponential growth rate of biomass, with a top doubling time of 1.8 days. The gas analysis also showed anti-correlation of CO2 uptake and O2 production, which along with the apparent stripping of the O2 to the equilibrium level by the microbubbles, strongly suggests that the bioreactor is not mass transfer limited, nor O2 inhibited. Removing O2 inhibition results in high growth rates and high density of biomass. 相似文献
115.
Titus S. Seilheimer Patrick L. Zimmerman Kirk M. Stueve Charles H. Perry 《Journal of Great Lakes research》2013
The Great Lakes watersheds have an important influence on the water quality of the nearshore environment, therefore, watershed characteristics can be used to predict what will be observed in the streams. We used novel landscape information describing the forest cover change, along with forest census data and established land cover data to predict total phosphorus and turbidity in Great Lakes streams. In Lake Superior, we modeled increased phosphorus as a function of the increase in the proportion of persisting forest, forest disturbed during 2000–2009, and agricultural land, and we modeled increased turbidity as a function of the increase in the proportion of persisting forest, forest disturbed during 2000–2009, agricultural land, and urban land. In Lake Michigan, we modeled increased phosphorus as a function of ecoregion, decrease in the proportion of forest disturbed during 1984–1999 and watershed storage, and increase in the proportion of urban land, and we modeled increased turbidity as a function of ecoregion, increase in the proportion of forest disturbed during 2000–2009, and decrease in the proportion softwood forest. We used these relationships to identify priority areas for restoration in the Lake Superior basin in the southwestern watersheds, and in west central and southwest watersheds of the Lake Michigan basin. We then used the models to estimate water quality in watersheds without observed instream data to prioritize those areas for management. Prioritizing watersheds will aid effective management of the Great Lakes watershed and result in efficient use of restoration funds, which will lead to improved nearshore water quality. 相似文献
116.
Vanessa Rose Gretchen Rollwagen‐Bollens Stephen M. Bollens Julie Zimmerman 《河流研究与利用》2019,35(9):1478-1488
Dams, increasingly common in riverine systems worldwide, are particularly prevalent on the Columbia River (CR) in the United States. Hydroelectric projects, including both storage and run‐of‐river (i.e., minimal storage) structures, on the mainstem CR highly manage water flow, often by releasing water over (rather than through) dams as “spill.” To test the effects of run‐of‐river dam spill on microplankton abundance and composition, we sampled above and below two dams in the lower CR before and during spill conditions in spring 2016 and during and after spill conditions in late summer 2007. We tested the effects of location (i.e., above vs. below dams), spill condition (i.e., before, during, and after spill), and their interaction on microplankton abundance. Generally, diatoms were most abundant during springtime, whereas cyanobacteria were most abundant in late summer. Most taxa were not significantly different in abundance above and below dams, regardless of spill status; although cyanobacteria abundance was marginally higher below dams in summer 2007 (p = .04). Abundances of all taxa were significantly different between pre‐spill and spill periods in spring 2016, whereas only diatom and flagellate abundances were significantly different between spill and post‐spill periods in summer 2007. We conclude that spill conditions may influence microplankton abundance, but are not likely to affect microplankton communities on either side of run‐of‐river dams on the CR. This is important information for dam managers concerned about ecosystem impacts of spill. 相似文献
117.
Zimmerman Jeffrey; Hess Allen K.; McGarrah Nancy A.; Benjamin G. Andrew H.; Ally Glenn A.; Gollan Jackie K.; Kaser-Boyd Nancy 《Canadian Metallurgical Quarterly》2009,40(6):539
The provision of psychological (e.g., psychotherapy, coparenting, mediation, collaborative divorce, child custody evaluation) services for families of divorce are growing specialties for many clinical and forensic psychologists. However, practice in domestic relations psychology, such as divorce and custody assessment and testimony, is a high-risk venture for incurring ethics complaints and law suits. The lead article and the three commentaries that follow enumerate the various roles practitioners might play, clarify how each role requires specific skill sets that may be outside one’s particular competence and necessitate additional training, describe how countertransferential issues arise, urge meticulous record keeping, discuss some of the subtleties of confidentiality and the releasing of information, describe how transparency in clarifying expectations leads to a lowering of contentiousness, and provide tips for divorce and forensic practice. The special challenges associated with psychologists being tempted to move beyond their role on a case and those of particularly high-risk situations (e.g., complaints of child abuse or domestic violence) are also discussed. Suggestions are offered to help psychologists better serve the public while taking steps to better inoculate themselves from complaints. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
118.
HI McFarland AA Lobito MM Johnson JT Nyswaner JA Frank GR Palardy N Tresser CP Genain JP Mueller LA Matis MJ Lenardo 《Canadian Metallurgical Quarterly》1999,162(4):2384-2390
Definition of the immune process that causes demyelination in multiple sclerosis is essential to determine the feasibility of Ag-directed immunotherapy. Using the nonhuman primate, Callithrix jacchus jacchus (common marmoset), we show that immunization with myelin basic protein and proteolipid protein determinants results in clinical disease with significant demyelination. Demyelination was associated with spreading to myelin oligodendrocyte glycoprotein (MOG) determinants that generated anti-MOG serum Abs and Ig deposition in central nervous system white matter lesions. These data associate intermolecular "determinant spreading" with clinical autoimmune disease in primates and raise important issues for the pathogenesis and treatment of multiple sclerosis. 相似文献
119.
120.
Acute hypovolaemia evokes abrupt, life-threatening hypotension and bradycardia. Hypotension can be evoked also by excitation of the caudal midline medulla (CMM). This study investigated the possible contribution of the CMM depressor area to hypotension evoked by acute hypovolaemia. Inactivation of the CMM, with either lignocaine or cobalt chloride did not alter resting arterial pressure. However lignocaine injections blocked the fall in arterial pressure, and cobalt chloride injections delayed the onset and significantly attenuated the size of hypovolaemic-evoked hypotension. These findings suggest that the CMM is a key region triggering hypotension after blood loss, and that the brain areas mediating cardiovascular response to challenges such as acute hypovolaemia are not the same areas that regulate resting arterial pressure. 相似文献