长江上游高洪水期泥沙输移特性

长江上游高洪水期(汛期)泥沙输移特性是决定三峡库区泥沙淤积的关键因素,直接关乎三峡水库使用寿命及综合效益的发挥。借助干、支流长系列水沙资料,分析了长江三峡水库入库寸滩站高洪水期泥沙输移特性,结果表明:近40 a来,寸滩站场次洪水中7 d洪量未出现趋势性变化,而7 d沙量显著减少,高洪水期输沙经历了“涨水输沙占优—涨、落水基本持平—落水输沙占优”的变化过程。2013年以前,寸滩站高洪水期径流及泥沙均主要来自于金沙江,而向家坝、溪洛渡水电站陆续投运后,2013—2019年寸滩站洪水场次(洪峰流量30 000 m³/s以上)共计14场。从径流来源来看,仅4场主要来自于金沙江,其余9场主要来自于嘉陵江,1场来自岷江;从泥沙来源来看,9场主要来自于嘉陵江,其余5场分别来自于沱江、岷江、横江,金沙江已不是寸滩站高洪水期过程中泥沙的主要来源区。研究成果可为三峡水库沙峰排沙调度、库尾减淤调度提供理论支撑,为长江泥沙治理提供保障。     

老挝南欧江梯级水电站二期厂房生活给水系统设计

水电站厂房生活给水系统应能够可靠、高效地为厂内工作人员提供满足要求的生活用水。老挝南欧江梯级水电站二期厂区附近均无可用的市政供水管,无法依靠市政供水系统为厂区提供生活用水。以老挝南欧江梯级水电站二期厂房生活给水系统设计为例,提出了针对远离城镇,无市政供水情况下,水电站厂房生活给水系统的设计思路、设计方案、设计的要点及难点。     

Transport properties of critical dilute solutions

On the basis of the isomorphism of critical phenomena, the behavior of transport properties of binary mixtures in the vicinity of the vapor-liquid critical line is considered. In particular, the renormalization of the singularity of the thermal conductivity in dilute critical solutions has been analyzed in detail. It is shown that the behavior of the thermal conductivity is determined by the critical background, i.e., the fluctuation-induced regular part, which diverges at the critical point of a solvent.     

一种高效的同尺寸长方体的装箱算法

针对应用广泛的同尺寸长方体货品的装箱问题,本文运用分层装载方案,根据货品的长宽高采用三种不同的层高,利用动态规划算法分别计算三种层的最大装载量,再通过背包算法对层进行组合,得出装箱的最优方案。该算法复杂度低,装载方案简单。     

浅谈GPS导航系统在油田运输管理中的应用

我油田地处华北东部,随着油田不断发展,对外承包业务愈来愈多。道路营运车辆也日益增多,营运范围也逐渐扩大,给道路运输经营管理与车辆合理调度工作提出了新的要求,而全球卫星定位系统的发展为道路运输管理的有效指挥、协调控制和管理提供了技术支持。本文结合GPS系统的原理,探讨GPS系统在油田运输管理中的应用。     

Photovoltaic effect and carrier transport mechanisms in Hg1-Mnxtdiodes

Hg_1-xMn_xTe semiconducting semimagnetic alloy has been examined in the context of its possible applications in infrared detectors. For analysis of detector properties the intrinsic carrier concentration has been calculated as a function of temperature and crystal composition. The starting material was In-doped Hg_1-xMn_xTe grown by the modified Bridgman method. The as-grown crystals with manganese content of 12-19% were p-type with carrier concentration and mobility of 100 cm²/ Vs at 77 K. An-type layer was formed on the surface by the annealing process in saturated Hg-vapour at 270-320° for 2 hrs. Capacitance-voltage curves have C^-3 dependence on applied voltage indicating that the junction is linearly graded. From standard electrical measurements and spectral characteristics the main detector parameters were determined and compared to those of Hg_1-xCd_xTe devices. The influence of material properties on detector parameters was analyzed. In order to estimate the carrier transport mechanisms, differential resistivities and current-voltage curves were measured over a wide range of temperaturesi.e. 25 to 300 K. From the temperature dependence of the R₀A product, it was established that at high temperatures (150-300 K) the carrier transport is dominated by a recombination-generation mechanism. In low temperature region the excess current at forward bias is probably attributed to carrier tunneling via energy states distributed randomly within the forbidden gap. At reverse bias the leakage surface or volume currents dominate in the carrier transport.     

DH-1型型砂水分自动测控系统

介绍了一种新型的型砂水分测控系统。它以单片机为主控机，采用自行 研制的电容式集成水分传感器对型砂水分进行测控。该系统应用先进的数据采集和自动控制技术，具有控制精度高、运行可靠、安装操作方便等特点，实际应用试验表明本系统较好地符合生产实际要求。     

Electrical transport in UNi0.5Sb2 single crystals

Single crystals of UNi₀.₅Sb₂ were investigated by means of Seebeck coefficient and Hall effect measurements in the temperature range 5–300 K. The results corroborated the occurrence of two magnetic phase transitions: from para- to antiferromagnetic state at T_N = 161.5 K and a spin-reorientation near T_t = 64 K. The first-order character of the latter feature was proved by studying in detail the electrical resistivity and the magnetic susceptibility of single-crystalline UNi₀.₅Sb₂ in the vicinity of T_t.     

Auxin and Root Gravitropism: Addressing Basic Cellular Processes by Exploiting a Defined Growth Response

Root architecture and growth are decisive for crop performance and yield, and thus a highly topical research field in plant sciences. The root system of the model plant Arabidopsis thaliana is the ideal system to obtain insights into fundamental key parameters and molecular players involved in underlying regulatory circuits of root growth, particularly in responses to environmental stimuli. Root gravitropism, directional growth along the gravity, in particular represents a highly sensitive readout, suitable to study adjustments in polar auxin transport and to identify molecular determinants involved. This review strives to summarize and give an overview into the function of PIN-FORMED auxin transport proteins, emphasizing on their sorting and polarity control. As there already is an abundance of information, the focus lies in integrating this wealth of information on mechanisms and pathways. This overview of a highly dynamic and complex field highlights recent developments in understanding the role of auxin in higher plants. Specifically, it exemplifies, how analysis of a single, defined growth response contributes to our understanding of basic cellular processes in general.