扫描面几何特征对扫描声强法确定声功率误差的影响

给出了扫描线密度的定义，用改进的矩形测量面方波扫描路径测量声功率的计算模型，建立了测量面的几何特征与误差之间的函数关系。分析结果表明：通过增加扫描垂直线条数、测量面上平行于扫描方向的边的长度或减小垂直于扫描方向的边的长度，都可以减小误差；对于正方形测量面，可以通过增加扫描垂直线条数，或在大于所求取的误差峰值点范围内增加测量面的边长来减小误差。     

Cross-cultural comparison of sound sensation and its prediction models for Korean traditional silk fabrics

In this study, cross-cultural comparison of sound sensation for Korean traditional silk fabrics between Korea and America was performed and prediction models for sound sensation by objective measurements including sound parameters such as level pressure of total sound (LPT), Zwicker’s psychoacoustic characteristics, and mechanical properties by Kawabata Evaluation System were established for each nation to explore the objective parameters explaining sound sensation of the Korean traditional silk. As results, Koreans felt the silk fabric sounds soft and smooth while Americans were revealed as perceiving them hard and rough. Both Koreans and Americans were pleasant with sounds of Gongdan and Newttong and especially Newttong was preferred more by Americans in terms of sound sensation. In prediction models, some of subjective sensation were found as being related mainly with mechanical properties of traditional silk fabrics such as surface and compressional characteristics.     

Seasonality in surface‐layer net zooplankton communities in Prince William Sound,Alaska

The upper‐layer net‐zooplankton community in Prince William Sound, Alaska, is characterized by strong seasonality. Abundance and wet‐weight biomass in the upper 50 m drop to fewer than 100 individuals and 10 mg m^?3 in February before rebounding to 5000 individuals and 600 mg m^?3 in June. Copepods dominate in all months, but are augmented by other prominent taxa, particularly pteropods and larvaceans during the late spring, summer and fall. The small copepods Pseudocalanus, Acartia and Oithona are common. Though much less abundant, larger calanoids like Neocalanus, Calanus and Metridia contribute substantially to the biomass in spring and early summer. Meroplankters like barnacle nauplii are also occasionally very abundant. Neocalanus, Calanus and Pseudocalanus all exhibit ontogenetic vertical displacement of populations when stage 5 copepodites (C5) leave the surface in late May and early June for deep water. This seasonality has implications for food‐webs supporting juvenile pink salmon (Oncorhynchus gorbuscha) and Pacific herring (Clupea pallasi) in Prince William Sound.     

Distribution, density and abundance of the western Baltic herring (Clupea harengus) in the Sound (ICES Subdivision 23) in relation to hydrographical features

Biomass and duration of the over-wintering period of the Rügen spring spawning herring stock (RHS) in the Sound (ICES Subdivison 23) were investigated as well as possible hydrographical factors affecting relative distribution and triggering southwards migration towards the spawning grounds. Monitoring was performed during 27 surveys over a 6-year period (1993–1998). Abundance of 45–165 000 t in August–February, 5–60 000 t in March–May, and <2000 t in June–July was found. This indicates a longer over-wintering period than hitherto assumed. The year classes 1988, 1991 and 1994 were relatively strong occurring in the Sound from age 2 (winter-rings) and abundance in autumn 1993 and 1996–1997 was relatively high. Relative year class strengths are in accordance with variations in larval indices at the spawning grounds. Decreasing abundance in late spring in the Sound was concordant with observed peaks in commercial landings and (subsequent) peak larval indices at the spawning grounds. Larger size groups seem to migrate southwards in spring before smaller herring size groups. Peak herring densities occur in the northern Sound in autumn and they do not concentrate near the southern Drogden threshold in spring before southwards spawning migration. Highest densities were found from 8 to 22 m below sea surface, and just below or in the halocline in areas with stratified water column. Indications of inflows to the Baltic triggering southwards migration can be observed at some occasions, however, these results are not conclusive because of relatively few biomass estimates in 1996–1998. The identified patterns in herring occurrence agree with some conclusions on migration routes for RHS from previously reported tagging studies, but the present investigations indicate prolonged over-wintering in the Sound. This report quantifies the abundance and distribution of herring in the Sound over the year on basis of repeated investigations, and investigates possible influence of hydrographical factors on distribution and migration.     

不同基质番茄育苗试验研究

选择在宁夏应用范围较广的中青广普型、中青番茄专用型、天缘壮苗2号、天缘广普型、嘉禾一型5种基质开展番茄育苗对比试验研究,结果表明：5种基质均都够充足供给番茄苗苗期生长的营养,适合宁夏大面积应用.其中中青番茄专用型、天缘壮苗2号基质在番茄育苗中综合性状较佳,可推荐为番茄育苗专用基质.     

关于“12121”气象声讯服务工作的思考

依据晋中市近几年来12121气象声讯服务的工作实际和12121自动答讯系统的相关资料,解析了晋中市气象声讯服务的现状及制约因素,归纳出气象声讯业务的一些规律和特点。对今后气象声讯服务工作提出了几点建议。