Spitzer discovery of very low luminosity objects

The Spitzer Space Telescope allows for the .rst time to search systematically for very low luminosity (≲0.1 L_⊙) objects (VeLLOs) associated with dense molecular cores. They may be the .rst candidate Class 0 sources with sub‐stellar masses. We describe such a source in the dense molecular core L1148. VeLLO natal cores show properties that are unusual for star‐forming cores. The low luminosity and in some cases the lack of prominent out.ow could be the result of the small gas supply near the VeLLO. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

不同播期下甜高粱含糖量变化及其与气象因子的关系

为确定甜高粱适宜播期及含糖量关键气象影响因子,以新疆玛纳斯地区甜高粱主栽品种为试验材料,对不同播期下甜高粱含糖量的变化及其与气象因子的关系进行了比较分析。结果表明,随生育期延迟,甜高粱茎秆总糖含量、蔗糖含量逐渐升高,成熟期最高;还原糖含量开花期达到最大值,灌浆期后逐渐下降,至成熟期最低。不同播期之间甜高粱茎秆含糖量存在显著差异(P<0.05),"新高粱3号"适宜早播,以4月25日播种较为适宜;T601适宜迟播,以5月8日播种较为适宜。相关分析结果表明,不同播期下不同品种甜高粱茎秆糖分含量与平均温度、降水、日照时数和风速存在显著相关(P<0.05),可根据气温、降水和日照时数进行甜高粱含糖量预测。     

Influence of temperature and salinity on germination of eelgrass (Zostera marina L.) seeds

Seagrass restoration as part of ocean ecosystem protection has been launched for many years all over the world, but intensive research on this subject in China has just begun in recent years. Seed broadcasting has been widely accepted as the most potentially useful method for seagrass restoration over large areas. We examined the influence of key environmental factors on seed germination to help promote eelgrass bed restoration. Under anoxic conditions, the influence of temperature and salinity on the germination rate of eelgrass (Zostera marina L.) seeds was examined at different combinations of four temperatures (4, 9, 14, and 24°C) and nine salinities (5 to 45, increment of 5). The effect of significant interaction of temperature and salinity on germination rate was observed (ANOVA) (P<0.001). The highest germination rate (83.3 ± 3.5)% was reached in 8 weeks at 14°C and salinity 5. Higher temperature significantly increased the germination rate at salinity 5 (P<0.001) during the whole observation period except for 24°C, while lower salinity significantly increased the germination rate at 14°C (P<0.001). Although significant interaction was found between temperature and salinity (P<0.001), the influence of salinity was stronger than that of temperature for the germination of eelgrass seeds. These results provide useful information for the propagation of artificial seedlings for seagrass restoration in China.     

禾谷缢管蚜种群动态的模糊聚类分析

田间调查结果表明，禾谷缢管蚜在麦田的聚集和扩散具有周期性发生的规律，种群在不同时间也表现不同状态。用模糊聚类法分析了禾谷缢管蚜的种群动态，将发生动态分为５ 个状态，即初盛状态、凋落（点片）状态、盛发状态，以及因外迁和死亡形成的衰减状态。经分析认为，化学防治应在初盛期进行     

网络空间物流信息系统的分析与探讨

现代物流业将成为中国经济发展的重要产业和新的经济增长点 ,目前我国已经建立了由铁路、公路、水路、航空和管道 5种运行方式组成的综合运输体系。物流中运输、商业分布、经济活动等都是在一定的地理空间中进行 ,而 GIS的研究对象就是地理空间。     

MODIS数据并行计算方法研究与实现

详细分析了MODIS数据辐射定标、投影变换实际操作过程中的并发性,提出了三种不同的任务分解策略,实现了两种预处理操作,并对试验数据进行分析比较,发现投影变换更适合于并行化处理,而按行和按列任务分解的效率要高于按波段的任务分解。     

Leaching evaluation of cement stabilisation / solidification treated kaolin clay

Sustainable land management often requires redevelopment of existing and often contaminated Brownfield sites over use of Greenfield or agricultural land. Stabilisation / solidification (S/S) offer a viable remediation option with particular suitability in treating heavy metal contaminants. However, uncertainties over long-term durability and previously cheap landfill disposal costs resulted in limited use in many countries. There is a need to characterise treated material and assess components containment and release, to improve S/S confidence and inform remedial design, using the evaluation of the leaching controlling mechanisms. To improve understanding of key features that will enable improvements to such designs, this paper presents an evaluation of leaching for CEM II stabilised kaolin, using the leaching behaviour of 4 main components—aluminium, silicon, calcium and sulphur. Results show no detrimental implications on chemical durability due to kaolin degradation with hydration under induced alkalinity, with increased formation of stable cementitious minerals. Availabilities for components show that aluminium and silicon had minimal leachability compared to total content, whilst calcium and sulphur show almost total leaching availability. Decreasing calcium and silicon leachability under natural chemical conditions with increased hydration duration supports the increased formation of stable cementitious products with time, using the products of kaolin dissociation.     

吕梁山西麓复兴剖面红黏土的磁性地层学研究

吕梁山西麓中上新世的一套厚层红黏土层记录了吕梁山前盆地的演化和吕梁山新近纪的隆升。山前不同的构造部位,各异的古地貌特征导致红黏土的堆积特征差别较大,柳林复兴地区黏土层的下部常含有数层化石层和薄厚不等的砾石层。本文对复兴地区的红黏土进行了岩石磁学和磁性地层学研究,得出了复兴地区红黏土及所含砾石层和化石层的古地磁年龄,并通过野外沉积特征以及粒度等指标探讨了复兴地区红黏土的形成过程。岩石磁学结果表明,红黏土中特征剩磁的载体为磁铁矿和赤铁矿。古地磁和生物化石显示复兴剖面的年龄为7.1～2.6Ma。其中所含厚层砾石层的古地磁年龄约为5.2Ma。两层化石层的年龄分别为～6.8Ma和～7.1Ma。剖面野外沉积特征和粒度变化显示柳林复兴地区红黏土堆积初期有水流作用的参与。     

Effects of feeding and stocking density on digestion of cultured Atlantic salmon Salmo salar L.

The combined effects of feeding rate （0.8%, 1.0%, and 1.2% initial body weight/day）, feeding frequency （two, three, and four times/day） and stocking density （10, 15, and 20 kg/m3） in recirculating aquaculture systems （RAS） on growth performance, digestion and waste generation of Atlantic salmon （Salmo salar L.） were investigated in an 8-week orthogonal experiment （L9（3）3） with a constant daily water renewal at 7.50% of total volume. No mortality occurred during the experimental period. Feed conversion ratio （FCR） varied from 0.90 to 1.13 and specific growth rate （SGR） ranged from 0.48% to 0.69%/day. SGR, thermal growth coefficient （TGC） and FCR were not significantly （P〉0.05） affected by the three factors, while net protein utilization （NPU） was significantly （P〈0.05） affected. Apparent digestibility coefficients （ADC） of dry matter in the present study were in the range 66.12%-73.55%. ADC in protein, lipid and energy were statistically different among all treatments and in the range of 90.07%-93.67%, 81.54%-89.15%, and 67.55%-71.87%, respectively. The proportion of mean total ammonia nitrogen excreted ranged from 1.37% to 1.64% of feed nitrogen at steady state, and the concentration of nitrogenous and phosphorus compounds were differently correlated to the three factors. The results will provide valuable reference data for culture management decisions in the Atlantic salmon farming industry.     

巴旦木春季低温霜冻灾害的气象指标分析

摘要：以3个当地主栽品种（莎车1号、莎车14号和莎车18号）为试材,在春季巴旦杏花蕾期至开花期,利用高精度冰箱进行花蕾、花朵和叶低温霜冻害模拟试验,结合历史灾情资料分析春季低温霜冻的强度与发生时段,确定巴旦杏晚霜冻冻害气象指标。结果表明,在开花期若遇到-4.0℃低温且持续2h,会出现轻度冻害;-4.0℃低温若持续4h,莎车1号（纸皮）、莎车14号（叶尔羌）和莎车18号（晚丰）三个品种均会发生冻害,减产幅度达到20%左右;若-6.0℃的低温霜冻持续达2h,三个品种都会发生严重冻害。