超分子主体化合物在分析化学中的应用研究进展

综述了近年来超分子主体化合物在分析化学领域的应用研究与进展。分别以冠醚、环糊精、杯芳烃、卟啉4类超分子为主体功能化合物的研究进行了详细的评述，并对这几类主体化合物在分析化学中的应用研究进行了展望。     

Moving beyond the fourth dimension with an IFC-based single project database

4D CAD has been an active research area for many years. The first generation 4D tools simulated construction schedules and demonstrated the potential benefits in several case studies. Researchers tried to improve the functionality of the first generation 4D tools by adding annotations and highlighting the building elements that have problems. The future generation 4D tools are expected to include more than these. It has been envisioned that 4D models would be part of project databases in order to take decisions related with different project dimensions.This paper presents the development and implementation of a new 4D planning tool which is a part of a product model-based project database. This tool brings the 4D simulation and cost estimation together and aims to contribute to what-if analysis in construction projects. The last part of the paper presents a case study in which the proposed prototype is evaluated.     

Lake-Level Change and Water Balance Analysis at Lake Qinghai,West China during Recent Decades

Lake Qinghai, the largest saline lake with an area of 4,260 km² (2000) and average depth of 21 m (1985) in West China, has experienced severe decline in water level in recent decades. This study aimed to investigate water balance of the lake and identify the causes for the decline in lake level. There was a 3.35-m decline in water level with an average decreasing rate of 8.0 cm year⁻¹ between 1959 and 2000. The lake water balance showed that mean annual precipitation between 1959 and 2000 over the lake was 357 ± 10 mm, evaporation was 924 ± 10 mm, surface runoff water inflow was 348 ± 21 mm, groundwater inflow was 138 mm ± 9 and the change in lake level was −80 ± 31 mm. The variation of lake level was highly positively correlated to surface runoff and precipitation and negatively to evaporation, the correlation coefficients were 0.89, 0.81 and −0.66, respectively. Water consumption by human activities accounts for 1% of the evaporation loss of the lake, implying that water consumption by human activities has little effect on lake level decline. Most dramatic decline in lake level occurred in the warm and dry years, and moderate decline in the cold and dry years, and relatively slight decline in the warm and wet years, therefore, the trend of cold/warm and dry climate in recent decades may be the main reasons for the decline in lake level.     

北京市部分学校教室采光照明现状分析

近年来我国学生视力不良检出率居高不下,并且呈现明显上升趋势,已经到了极为严重的程度.学校教室的采光照明问题是保护学生视力健康的重要部分.2004年我国重新修订了国家标准〈建筑照明设计标准〉GB50034-2004.本文对北京市部分大中小学校进行采光照明的调查分析,结果显示,北京市学校教室采光照明问题十分严重,与国家标准要求差距很大,在被调查的39间教室中,窗地面积比达标率为20.5%,课桌面照度达标率为25.6%,黑板照度达标率为零.     

Calculations of optical properties in p-doped nitrides quaternary alloys multiple quantum wells

We present theoretical photoluminescence (PL) and absorption spectra of p-doped InGaN/AlInGaN and AlInGaN/InGaN multiple quantum wells (MQWs). The calculations were performed within the k.p method by means of solving a full eight-band Kane Hamiltonian together with the Poisson equation in a plane wave representation, including exchange–correlation effects within the local density approximation. Strain effects due to the lattice mismatch and an internal electric field are also taken into account. We show that by changing the In and Al composition we can reach short and long emission wavelengths. The trends in the calculated Stokes shift, due to many-body effects within the quasi-two-dimensional hole gas (2DHG), are analyzed as a function of the acceptor doping concentration. Since the studies of optical properties of quantum wells based on nitrides quaternary alloys are at an early stage, the results reported here will provide guidelines for the interpretation of forthcoming experiments.     

Application of spent grains to increase porosity in bricks

The dumping of spent grains is going to be more difficult because of the increasing number of cattle. That means new ways of dumping must be developed.The goal of the work was to test the technical properties of bricks produced with spent grains added to increase porosity.The flexural strength of the fired samples remained at 8.5 MPa; the air-dried samples exhibited a small increase in flexural strength. The shrinkage and true density were almost identical, while the raw density, capacity for water absorption and open porosity showed minor differences.In the large-scale experiment no problems were observed during the production. The bricks produced with spent grains possessed a comparable or higher strength, a higher porosity and a reduced density after firing than those from a standard production clay. Because of the lower sintering temperatures the fired clay product was more strongly sintered, exhibiting both greater strength and higher porosity.     

Photocatalytic evolution of hydrogen over mesoporous TiO2 supported NiO photocatalyst prepared by single-step sol–gel process with surfactant template

Photocatalytic activity of mesoporous titania supported nickel oxide photocatalyst synthesized by single-step sol–gel (SSSG) process combined with surfactant-assisted template method was investigated for hydrogen evolution from an aqueous methanol solution, in comparison with one prepared by conventional incipient wetness impregnation (IWI) method. In single-step sol–gel process, nickel precursor was introduced into the titania sol prepared with the aid of a surfactant template behaving as pore-controlling agent to attain meso-scaled pore. The single-step sol–gel photocatalyst was experimentally found to enhance the photocatalytic evolution of hydrogen rather than the impregnated one. The optimum level of nickel loading in photocatalytic activity test for single-step sol–gel method was slightly higher than that for incipient wetness impregnation method. Characterization results demonstrated the significant modification of physical characteristics of the single-step sol–gel photocatalyst, anticipated to relating to the observation of higher photocatalytic hydrogen evolution activity.     

柴达木盆地天然气中稀有气体同位素特征

为了确定柴达木盆地勘探新层系，测试并分析了该盆地5个油气田的8个天然气样品的氦、氩同位素比值，探讨了其在大地构造背景、大地热流和气源方面的示踪意义。研究结果如下：①柴达木盆地8个天然气样品³He/⁴He值分布在2.0×10^-8～5.48×10^-8的范围，总体平均为3.7×10^-8，均在10^-8量级，体现了典型的壳源成因氦同位素的特征。②据³He/⁴He计算的大地热流值较低，分布于41.2~48.2 mW/m²之间，平均44.9 mW/m²，低于东部地区大地热流平均值73 mW/m²，表明该盆地具有较稳定的构造背景。③根据天然气⁴⁰Ar/³⁶Ar的年代积累效应，结合烃源岩分布特征推测，柴达木盆地东部凹陷区伊克雅乌汝构造伊深1井天然气应源于上第三系；西部坳陷区尕斯油田尕斯8-6井和尕斯475井天然气应源于下第三系；碱山构造碱1井天然气应源于侏罗系，碱山构造碱2井的天然气应源于上第三系；北缘块断带南八仙油气田仙试1井的天然气应源于侏罗系；南八仙油气田仙试8井和马北构造马北1井的天然气可能主要源于侏罗系。