小房间尺寸“合适比例”量化评估方法的探讨

为确保小尺度房间低频重放音质,国内外组织与机构、声学专家提出了若干房间尺寸"合适比例"推荐值。长久以来声学工作者一直比较关注的是这些比例究竟"合适"到什么程度,如何选择并用于声学设计中。因此如何进行定量评估这些小房间尺寸"合适比例"就显得十分必要。以一个新的视角,借助互联网和小房间声学计算程序,对上述比例进行重新审视。通过对若干推荐的"合适比例"在不同容积下的计算数据进行统计、分析,得出小房间各种"合适比例"下声染色风险大小的定量评估结果(排序)。此外,还提出如何通过计算寻找新的小房间尺寸"合适比例"的途径,并给出了几种新的"合适比例"计算结果。最后,提出最值得推荐的6种小房间长、宽、高尺寸"合适比例",每种比例至少采用10种以上的房间容积进行计算,并对这些比例的适用条件及相关事项进行了讨论。

小房间长、宽、高“合适比例”的运用及优化

在刚性矩形封闭房间内所激发的谐振频率的分布均匀程度决定于房间长、宽、高尺寸的比例。合适的比例对降低房间低频声染色起着至关重要的作用。首先根据房间"合适比例"的量化评估方法给出几种最值得推荐的房间长、宽、高尺寸的"合适比例"。然后根据不同使用场合运用这些"合适比例"。然而这些"合适比例"在使用上具有一定的局限性,因而对于不宜采用这些比例的房间可以通过计算机程序进行尺寸或比例的优化,以提高房间空间利用率,并减轻声染色对房间音质的不利影响。

Palatability of Water-Soluble Extracts of Protein Sources and Replacement of Fishmeal by a Selected Mixture of Protein Sources for Juvenile Turbot(Scophthalmus maximus)

Poor palatability is a limiting factor for replacing fishmeal with other protein sources in aquaculture. The water-soluble molecules with low molecular weights are the major determinants of the palatability of diets. The present study was conducted to investigate the palatability of water-soluble extracts from single protein source(single extract pellets) and the mixture of these extracts with different proportions(blended extract pellets) in juvenile turbot(Scophthalmus maximus). Then according to the palatability of blended extract pellets, an optimal mixture proportion was selected, and a new protein source made from raw protein materials with the selected proportion was formulated to replace fishmeal. Summarily, the palatability of single extract pellets for turbot was descendent from fishmeal to pet-food grade poultry by-product meal, wheat gluten meal, soybean meal, peanut meal, meat and bone meal, and corn gluten meal. Subsequently, according to the palatability of single extract pellets, 52 kinds of blended extract pellets were designed to test their palatability. The results showed that the pellets presented remarkably different palatability, and the optimal one was diet 52(wheat gluten meal: pet-food grade poultry by-product meal: meat and bone meal: corn gluten meal = 1:6:1:2). The highest ingestion ratio(the number of pellets ingested/the number of pellets fed) was 0.73 ± 0.03, which was observed in Diet 52. Then five isonitrogenous(52% crude protein) and isocaloric(20 k J g^(-1) gross energy) diets were formulated by replacing 0(control), 35%, 50%, 65% and 80% of fishmeal with No.52 blending proportion. After a 10-weeks feeding trial, a consistent feed intake was found among all replacement treatments. Replacement level of fishmeal up to 35% did not significantly influence final body weight, specific growth rate, feed efficiency ratio, and protein efficiency ratio of turbot. Therefore, the water-soluble extracts of protein sources play an important role in improving the palatability of non-fishmeal protein sources in aquafeed.

子宫动脉栓塞治疗子宫肌瘤的临床疗效观察

目的:探讨双侧子宫动脉栓塞术治疗子宫肌瘤的临床疗效。方法:采用介入技术于2006年5月～2009年9月对50例子宫肌瘤患者均进行子宫肌瘤供血动脉的栓塞治疗,应用专用的5F子宫动脉导管,选择比例合适的栓塞剂:平阳霉素8 mg+碘油10 ml(法国进口)+利多卡因2 ml,使用1∶1的比例(即肌瘤的大小与栓塞剂的比例),较大肌瘤(8cm左右)或多发肌瘤或血供丰富者加用明胶海绵颗粒加强栓塞。结果:插管成功率为100%。随访3～12个月,B超或CT示术后3个月肌瘤体积平均缩小40%～60%,术后6个月肌瘤体积平均缩小60%～90%。12例患者肌瘤消失,并均伴有月经量的明显减少,临床症状明显改善。无1例严重并发症发生。结论:子宫肌瘤介入治疗是一种安全、有效且能保留子宫的微创治疗方法,特别适用于年轻、有生育要求或不愿手术的患者。选择合适比例的栓塞剂对较大肌瘤及多发肌瘤疗效更佳。