排序方式: 共有44条查询结果,搜索用时 31 毫秒
1.
指出了气携式液液旋流器是港区小型化、船载化洗舱、压仓含油废水预处理的关键设备.采用流固耦合数值模拟方法再现压缩机进气、油水旋流与设备本体的整体气浮—旋流—分离耦合计算模型 ,对其核心部件微孔旋流套管的构型、孔径、内外压差及腔内流场分布进行了三维数值模拟 ,得到了微孔旋流腔内汽、水、油三相的流场分布 ,合理确定了注气腔气—水平衡分压、溢流比和微孔孔径 ,并模拟了压缩机、潜水泵正常工况下进气、进水、出水、油污溢流的流量、流速波动范围 ,为该设备的一体化构型设计和加工选材提供了参考数据. 相似文献
2.
The Andean seed crop quinoa (Chenopodium quinoa Willd.) is traditionally grown under drought and other adverse conditions that constrain crop production in the Andes, and it is regarded as having considerable tolerance to soil drying. The objective of this research was to study how chemical and hydraulic signalling from the root system controlled gas exchange in a drying soil in quinoa. It was observed that during soil drying, relative gs and photosynthesis Amax (drought stressed/fully watered plants) equalled 1, until the fraction of transpirable soil water (FTSW) decreased to 0.82 ± 0.152 and 0.33 ± 0.061, respectively, at bud formation, indicating that photosynthesis was maintained after stomata closure. The relationship between relative gs and relative Amax at bud formation was represented by a logarithmic function (r2 = 0.79), which resulted in a photosynthetic water use efficiency WUEAmax/gs of 1 when FTSW > 0.8, and increased by 50% with soil drying to FTSW 0.7–0.4. Mild soil drying slightly increased ABA in the xylem. It is concluded that during soil drying, quinoa plants have a sensitive stomatal closure, by which the plants are able to maintain leaf water potential (ψl) and Amax, resulting in an increase of WUE. Root originated ABA plays a role in stomata performance during soil drying. ABA regulation seems to be one of the mechanisms utilised by quinoa when facing drought inducing decrease of turgor of stomata guard cells. 相似文献
3.
目的 观察参附养心汤治疗老年阳虚水泛型慢性心力衰竭的临床效果。方法 将老年阳虚水泛型慢性心力衰竭患者92例随机分为观察组和对照组,每组46例。对照组采用西医常规治疗,观察组在对照组治疗方法基础上给予参附养心汤治疗。治疗4周后,对两组患者临床疗效、脑钠肽(BNP)、6 min步行距离、心功能指标[左心室舒张末期容积(LVEDV)、收缩末期容积(LVESV)、左心室射血分数(LVEF)]及细胞炎性因子[白细胞介素-6(IL-6)、肿瘤坏死因子(TNF-α)、超敏C-反应蛋白(hs-CRP)]进行比较。结果 治疗4周后,观察组总有效率为89.1%,显著高于对照组71.7%,差异具有统计学意义(P<0.05);观察组的BNP水平显著低于对照组,而6 min步行距离显著高于对照组,差异具有统计学意义(P<0.05);观察组的LVEDV、LVESV均显著低于对照组,而LVEF高于对照组,差异具有统计学意义(P<0.05);观察组的血清hs-CRP、IL-6及TNF-α水平均显著低于对照组,差异具有统计学意义(P<0.05)。结论 参附养心汤能显著改善老年阳虚水泛型慢性心力衰竭患者的心功能指标,降低BNP水平,减轻炎症反应,提高运动耐量,疗效显著。 相似文献
4.
5.
This review focuses on the effects of freezing storage on the microstructure and baking performance of frozen doughs, and provides an overview of the activities of dough improvers, including emulsifiers, hydrocolloids and other improvers used in frozen dough applications. The overall quality of bread baked from frozen dough deteriorates as the storage of the dough at sub-zero temperatures increases due to several factors which are discussed. Lipid-related emulsifiers such as diacetyl tartaric acid esters of mono and diglycerides and sucrose esters employed as anti-staling agents, dough modifiers, shortening sparing agents, and as improvers for the production of high-protein bread have also been employed in frozen doughs. Hydrocolloids are gaining importance in the baking industry as dough improvers due to their ability to induce structural changes in the main components of wheat flour systems during breadmaking steps and bread storage Their effects in frozen doughs is discussed. Other dough improvers, such as ascorbic acid, honey and green tea extract, are also reviewed in the context of frozen doughs. 相似文献
6.
通过新疆金沟河弯道式引水枢纽改建工程模型试验研究,提出了在弯道内增设中导流堤和溢流侧堰的工程措施,较好地解决了第一代弯道式引水枢纽弯道过宽而产生的泥沙淤积和引水等问题,对于弯道式引水枢纽的改建和设计具有参考作用。 相似文献
7.
本研究应用层次分析法和模糊综合评判原理,提出了过水围堰导流方式选择的模糊层次综合评判方法 相似文献
8.
分隔式循环水池塘养殖系统设计与试验 总被引:3,自引:1,他引:2
为了解决池塘养殖设施化程度低、净化能力不足和排污效果差等问题,设计了分隔式循环水池塘养殖系统。该系统由20%水面的吃食性鱼类养殖区和80%水面的滤杂食性鱼类养殖区构成,配置过水堰、螺旋桨式和水车式推流装置、集污和吸污装置等养殖系统设施和装备。性能测试结果表明:螺旋桨式推流装置提水动力效率为340 m~3/(k W·h),流量为204 m~3/h,空载噪音为60 d B;水车式推流装置提水动力效率为360 m~3/(k W·h),流量为180 m~3/h,空载噪音为67 d B;过水堰过水的总流量约为331 m~3/h,利用水循环装备实现水体流动可实现水体日交换量7 900 m~3,达到养殖池塘水体的50%左右。利用推流装置搅动水体,可实现水体大范围的对流,交替暴晒水体,增加水体中的溶解氧,试验池塘中下层溶解氧水平比对照塘高出59.5%,试验池塘叶绿素a浓度比对照塘低,说明一定程度上限制了浮游植物过渡繁殖。该养殖系统可为池塘健康养殖系统模式构建提供参考。 相似文献
9.
Root restriction often depresses photosynthetic capacity and the mechanism for this reduction, however, remains unclear. To identify the mechanism by which root restriction affects the photosynthetic characteristics, tomato (Lycopersicon esculentum Mill.) seedlings were subjected to root restriction stress with or without supplemental aeration to the nutrient solution. With the development of the root restriction stress, CO2 assimilation rate was decreased only in confined plants without supplemental aeration. There were also significant decreases in leaf water potential, stomatal conductance (gs), intercellular CO2 concentration (Ci), and increases in the stomatal limitation (l) and the xylem sap ABA concentration. Meanwhile, the maximum carboxylation rate of Rubisco (Vcmax) and the capacity for ribulose-1,5-bisphosphate regeneration (Jmax) also decreased, followed by substantial reductions in the quantum yield of PSII electron transport (ΦPSII). Additionally, root restriction resulted in accumulation of carbohydrates in various plant tissues irrespective of aeration conditions. It is likely that root restriction-induced depression of photosynthesis was mimicked by water stress. 相似文献
10.
As part of the interdisciplinary investigation of Calanus finmarchicus migrations between oceanic and shelf areas off north-west Europe (the ICOS project), a three-dimensional, prognostic baroclinic circulation model system, consisting of a coarse and a nested fine scale model, was constructed. The aim was to simulate the flow fields around Iceland, the Faroe Islands and the north-west European continental shelf and slope, including the northern North Sea. The coarse scale model covered the northern North Atlantic and provided the far field flow to the finer scale model. The latter was initialized and forced with climatological seasonal (winter and spring) means of temperature, salinity, river run-off, and other parameters necessary for the calculation of heat fluxes. Seasonal average simulations of flow and hydrographic conditions were performed, together with simulations of specific scenarios of uniform wind forcing from different directions. A feature common to all the results was a topographically guided northwards flow along the continental shelf edge, with a southwards counter-flow in the vicinity of the Faroe–Shetland Channel. The extent and strength of the shelf edge current, of its counter flow, and of the re-circulation cell in the northern North Sea, were dependent on the prevailing wind direction. The modelling results were consistent with the accepted circulation patterns in the area, and a comparison with field measurements in the Faroe–Shetland Channel showed that the main characteristics of the flow were well replicated, although the estimated strength of the slope current was somewhat less than in the field observations. 相似文献