煤矿用无机固化发泡材料的制备

研究了所制备发泡剂与材料干密度的关系,发现发泡剂掺量＜1.5％,成型良好;大于该值后,干表观密度显著下降;材料配比中砂、粉煤灰按照0.54,2∶1的比例调试,发现与水泥净浆相比抗压强度有所下降,但是其容重有所增加;早强剂的用量增加,其凝固时间明显缩短,对后期抗压强度影响不大.最后通过实验筛选出干密度分别为800,900,1 000 kg/m3的材料配比进行相关性能测试,测试发现该发泡材料具有前期强度和28 d龄期抗压强度高的特点.     

Nano-HA/PLA复合材料的制备与性能评价

采用均匀沉淀法制备纳米羟基磷灰石（nano-HA）粉末.采用溶液共混-超声分散（SUD）-溶剂挥发法,制备纳米羟基磷灰石（nano-HA）/聚乳酸（PLA）复合材料薄膜,并对其均匀性、热性能等进行研究.结果表明,材料分散均匀,纳米羟基磷灰石与聚乳酸基体之间结合良好.     

TDI双管板换热器制造质量的控制简

介绍了TDI双管板换热器的结构特点和深孔强度胀接技术。简述了制造过程中的质量控制关键点。通过用模拟管板进行了内管板胀接工艺评定的方法,采取了控制管孔加工精度、强度胀接、管板组装、调整开槽间距及宽度、安排合理的胀接焊接次序、选择合适的胀接压力等措施;采用了新的检验和检测技术,保证了产品质量;增设了压力传感器,完善了安全监测系统。     

Low-Power Design of Ethernet Data Transmission

For the reliability and power consumption issues of Ethernet data transmission based on the field programmable gate array （FPGA）, a low-power consumption design method is proposed, which is suitable for FPGA implementation. To reduce the dynamic power consumption of integrated circuit （IC） design, the proposed method adopts the dynamic control of the clock frequency. For most of the time, when the port is in the idle state or lower-rate state, users can reduce or even turn off the reading clock frequency and reduce the clock flip frequency in order to reduce the dynamic power consumption. When the receiving rate is high, the reading clock frequency will be improved timely to ensure that no data will lost. Simulated and verified by Modelsim, the proposed method can dynamically control the clock frequency, including the dynamic switching of high-speed and low-speed clock flip rates, or stop of the clock flip.     

褐煤超大型直管式气流干燥装置工业生产的设计

根据褐煤高水分、易燃易爆的特点,介绍了褐煤超大型直管式气流干燥装置工业生产的设计思路,针对调试运行过程中出现的问题提出了切实可行的解决方案。     

Experimental Studies on the Self-Shielding Effect in Fissile Fuel Breeding Measurement in Thorium Oxide Pellets Irradiated with 14 MeV Neutrons

The 14 MeV neutrons produced in the D-T fusion reactions have the potential of breeding Uranium-233 fissile fuel from fertile material Thorium-232. In order to estimate the amount of U-233 produced, experiments are carried out by irradiating thorium dioxide pellets with neutrons produced from a 14 MeV neutron generator. The objective of the present work is to measure the reaction rates of 232 Th + 1 n → 233 Th → 233 Pa → 233 U in different pellet thicknesses to study the self-shielding effects and adopt a procedure for correction. An appropriate assembly consisting of high-density polyethylene is designed and fabricated to slow down the high-energy neutrons, in which Thorium pellets are irradiated. The amount of fissile fuel ( 233 U) produced is estimated by measuring the 312 keV gammas emitted by Protactinium-233 (half-life of 27 days). A calibrated High Purity Germanium (HPGe) detector is used to measure the gamma ray spectrum. The amount of 233 U produced by Th 232 (n, γ) is calculated using MCNP code. The self-shielding effect is evaluated by calculating the reaction rates for different foil thickness. MCNP calculation results are compared with the experimental values and appropriate correction factors are estimated for self-shielding of neutrons and absorption of gamma rays.     

Effects of land use and changes in cover on the transformation and transportation of iron:A case study of the Sanjiang Plain,Northeast China

Wetland reclamation has been ongoing in the Sanjiang Plain since the mid-1950s,which has resulted in major changes in wetlands and the agriculture ecosystem in the region that have influenced the iron output to the Sea of Okhotsk and limited the primary productivity in the North Pacific Ocean.This study was conducted to investigate the chemical forms of iron in different aquatic environments(agricultural water including groundwater,paddy water,and canal water;wetland water including marsh water,marsh stream...     

Implications of the Methods Chosen for the Measurement of the Statistical Properties of Photographic Images

A survey is made of current opinions on the measurement of transfer functions and noise-power spectra of photographic materials. Conclusions are drawn about the difficulties introduced by the particular form of non-linearity found in the photographic process which lead to suggestions that future work moy need to use analytical techniques accepting such non-linearities. In such analyses. digital computers will be necessary, and some early work is described in which use is made of direct digital feed-out of data from a microdensitometer.     

Mechanochemical Synthesis and Characterization of Nanocrystalline Copper-Cobalt Ferrites

Nanocrystalline copper-cobalt ferrites with composition Cu_(1-x)Co_xFe_2O_4,where x = 0.2 and 0.8,were synthesized by mechanochemical treatment of co-precipitated precursors.The ferrite powders were characterized by XRD and Mossbauer spectroscopy.Results proved obtaining of spinel ferrites with crystallite size smaller than 10 nm.Increasing of crystallite size of samples with increasing of mechanochemical treatment duration was established,too.Catalytic properties of obtained ferrites were tested in reactions of oxidation of CO,methanol and dimethyl ether.High catalytic activity of nanocrystalline copper-cobalt ferrites toward CO and CH_3OH(about 100% conversions of CO and CH_3OH at 160 ℃)and moderate activity toward(CH_3)_2O oxidation were established.The results obtained revealed that the Co/Cu atomic ratio is an important factor determinant the behavior of catalysts toward methanol and DME oxidation.     

Simulation of free-surface flow using a boundless grid

Physically based fluid simulation in recent years has been successful for small-scale fluids such as liquid in a cubic cavity.However,for boundless free-surface flow of large scale and irregular area,there is a critical trade-off between simulation efficiency and accuracy because of the restriction of the traditional regular computational grids.This paper introduces boundless computational grids based on hierarchical runlength encoding to simulate large-scale free-surface flow.We first modeled the free-surface flow with a lattice Boltzmann method,and calculated the surface curvature in the update process.We then introduced an effective method with which to calculate the surface curvature according to the surface tension so that the surface detail was enhanced,and obtained the curvature of each surface effectively as it was extracted.Furthermore,we dynamically compressed and indexed the computational cells with the improved hierarchical run-length encoding algorithm,so that the grid expands dynamically according to the fluid flow and the computational resources used were proportional to the volume of the fluid.Finally fluids in different situations were simulated realistically.The proposed method makes the best of the computational resources to perform the simulation with high resolution,and dynamically allocates resources so that the fluid can expand in random directions without boundaries,which is suited to the simulation of large-scale visual scenes.