小型计算机在冷库制冷工艺过程中的应用

本文介绍小型工业控制机在一座万吨级冷库制冷工艺过程控制中的应用.简要论述了方 案选择、系统设计、可靠性措施及投产运转情况.鉴于制冷系统具有大惯性的特点,采用价格 低廉、功能较简单的JS-10B机作实时过程控制,比较充分地发挥了简易小型机的功能.通过 软硬件结合的措施,提高了本系统的可靠性与抗干扰性.     

膜法富氧技术及其应用研究

介绍了作者在膜法富氧技术方面的研究进展，并将膜法与其他制氧方法进行了比较，最后讨论了膜法富氧技术目前的有关应用，着重研究了膜法富氧在有色金属冶炼，硅酸盐窑炉，化铁炉，加热炉，医疗保健和柴油机增氧等方面的典型应用。     

River basin water resources management in China: a legal and institutional assessment

China's rivers face major challenges arising from social and economic development, particularly associated with pollution and over-abstraction. Although these issues vary significantly across the country, China has adopted a national, unified approach to manage water resources in a river basin context. This paper assesses the legal and institutional arrangements for river basin management in terms of decentralization and centralization. It considers the appropriate roles for the different levels of government, including providing for participation and integration across these levels. It proposes strengthening institutional development and capacity building in the future.     

珠江流域水资源管理系统总体设计

根据珠江流域水资源管理职能及管理现状,明确了珠江流域水资源管理系统在国家水资源管理系统和珠江委水利信息化顶层设计中的定位,设计了水资源管理系统总体框架,其功能涵盖了信息采集与传输系统、计算机网络系统、数据资源管理平台、应用支撑平台、业务应用系统等方面.     

Synthesis and characterization of Li1.05Co0.3Ni0.35Mn0.3M0.05O2 (M=Ge,Sn)cathode materials for lithium ion battery

In order to improve the electrochemical performance and thermal stability of Li_1.05Co_1/3Ni_1/3Mn_1/3O₂ materials,Li_1.05Co_0.3Ni_0.35Mn_0.3M_0.05O₂（M=Ge,Sn）cathode materials were synthesized via co-precipitation method.The structure,electrochemical performance and thermal stability were characterized by X-ray diffraction（XRD）,charge/discharge cycling,cyclic voltammetry（CV）,electrochemical impedance spectroscopy（EIS）and differential scanning calorimetry（DSC）.ESEM showed that Sn-doped and Ge-doped slightly increased the size of grains.XRD and CV showed that Sn-doped and Ge-doped powders were homogeneous and had the better layered structure than the bare one.Sn-doped and Ge-doped improved high rate discharge capacity and cycle-life performance.The reason of the better cycling performance of the doped one was the increasing of lithium-ion diffusion rate and charge transfer rate.Sn-doped and Ge-doped also improved the mateials thermal stability.     

Application of pressure relief and permeability increased by slotting a coal seam with a rotary type cutter working across rock layers

Pressure relief to increase permeability significantly improves gas extraction efficiency from coal seams. In this paper we report results from simulations using FLAC^3D code to analyze changes in coal displacement and stress after special drill slots were formed. We investigated the mechanism of pressure relief and permeability increase in a high-gas and low-permeability coal seam through the modeling of gas flow. This allows the development of the technology. Slotting across rock layers in the coal seam with a rotary type cutter was then applied in the field. The results show that pressure relief and permeability increases from slotting the coal seam can increase the transport and the fracture of the coal. This expands the range of pressure relief from the drilling and increases the exposed area of the seam. The total quantity of gas extracted from slotted bore holes was three times that seen with ordinary drilling. The concentration of gas extracted from the slotted drills was from two to three times that seen using ordinary drills. The gas flow was stable at 80%. Improved permeability and more efficient gas extraction are the result of the slotting. The roadway development rate is increased by 30–50% after gas drainage. This technology diminishes the lag between longwall production and roadway development and effectively prevents coal and gas outburst, which offers the prospect of broad application.     

Technology and application of pressure relief and permeability increase by jointly drilling and slotting coal

Difficulties with soft coal seams having a high gas content and high stress levels can be addressed by a technology of pressure relief and permeability increase. Slotting the seam by auxiliary drilling with a water jet that breaks the coal and slots the coal seam during the process of retreat drilling achieves pressure relief and permeability increase. Improved efficiency of gas extraction from a field test, high gas coal seam was observed. Investigating the theory of pressure relief and permeability increase required analyzing the characteristics of the double power slotting process and the effects of coal pressure relief and permeability increase. The influence of confining pressure on coal physical properties was examined by using FLAC3D software code to simulate changes of coal stress within the tool destruction area. The double power joint drilling method was modeled. Field experiments were performed and the effects are analyzed. This research shows that there is an “islanding effect” in front of the joint double power drill and slotting equipment. The failure strength of the coal seam is substantially reduced within the tool destruction area. Drilling depths are increased by 72% and the diameter of the borehole is increased by 30%. The amount of powdered coal extracted from the drill head increases by 17 times when using the new method. A 30 day total flow measurement from the double power drilled and slotted bores showed that gas extraction increased by 1.3 times compared to the standard drilled bores. Gas concentrations increased from 30% to 60% and were more stable so the overall extraction efficiency increased by a factor of two times.     

Evolution and distribution of macroscopic gas channels in an overburden strata

The evolution of gas bearing channels in the roof, and their spatial distribution, was studied. A complete consideration of gas flow changes through the stress–strain changes in the roof near a working face is made. The theoretical abutment pressure distribution using displacement monitors and borehole visual recording instruments allow a theoretical analysis. Field test research determined the conditions for formation of macroscopic gas channels. These appear along the working face roof, normally distributed to it. These results show that the coal rock stratification becomes a macroscopic gas channel boundary if its deformation is less than the lower layer, or greater than the layer above it. At the same time the stability is greater than the distance from the roof for hanging dew conditions. The working face advances and the roof gas channels experience a cycle of development. Microscopic channels dominate the initial stage then macroscopic gas channels form, develop, and close. The evolution of the macroscopic channels depends on the ratio between the distances from the new compaction area in the goaf to the initial stress area in front of the working face. The amount of daily advance of the face also affects channel development. The experimental observations in one mining area showed that the main gas channels are located about 2 and 6.2 m above the lower surface of the roof and that they have an evolution period 7 to 11 days long.     

Anaerobic degradation of purified terephthalic acid wastewater using a novel, rapid mass-transfer circulating fluidized bed

The anaerobic treatability of purified terephthalic acid (PTA) wastewater in a novel, rapid mass-transfer fluidized bed reactor using brick particles as porous carrier materials was investigated. The reactor operation was stable after a short 34 day start-up period, with chemical oxygen demand (COD) removal efficiency between 65 and 75%, terephthalate (TA) removal efficiency between 60% and 70%, and system organic loading rate (OLR) increasing from 7.37 to 18.52 kg COD/m(3) d. The results demonstrate that the reactor is very efficient, and requires a low hydraulic retention time (HRT) of 8 h to remove both TA and COD from the high-concentration PTA wastewater. The system also has high resistance capacity to varied OLR.     

基于光伏微网的PI-dP&O高性能MPPT控制器的设计

通过采用PI-dP&O模块、Buck-Boost电路与具有电流闭环控制的抑制积分饱和的PI控制器相结合的策略,设计出一种具有高性能的MPPT控制器。此控制器具有软件实现简单、适应性好、成本低廉等优点。在Matlab实验平台上将此高性能的MPPT控制器与传统的MPPT控制器进行对比,并应用到光伏微网中,充分显示其优越性和可行性。