Unusual W-shaped Galvanic Cell Model of ISCC of α-brass in Neutral Mattsson''''s Solution

Intergranular stress corrosion cracking(ISCC) of α-brass in neutral Mattsson's solutionwas found to be controlled by an unusual"W"-shaped galvanic cell whose cathode is thegrain boundary oxide film (G.B.0. film) andsurface film and the anode is fresh metal atthe cracked tip on both sides of the G.B.0.film. Redox reactions involved in the cellhave been proposed here. According to thismdel, initidtion of ISCC is caused by therupturing of surface film along grain boundaries,thus forming a galvanic cell. Propagation ofISCC resulted from alternate advances of G.B.0.film and dissolution on both sides of G.B.0.film caused by the effect of electrochemicalreaction. This work developed an effective approachto investigate the embrittlement process atthe tip of the crack, by increasing the lengthof the embrittlement region through constantstrain test and distinguishing the morphologyand the nature of the corrosion products byoptical microscopy and scanning electronmicroscopy (SEH).     

Studies and advances on joint source-channel encoding/decoding techniques in flow media communications

Joint source-channel coding/decoding (JSCC/JSCD) techniques in flow media communications have become a state-of-the-art and one of the challenging research subjects in the spatial communication area. They have great application prospective and deep impact in various manned space flights, satellite missions, mobile radio communications and deep-space explorations. In the last few years, there have been influential achievements in JSCC/JSCD studies. This paper aims at an introduction to the basic principles o...     

抗人A血型杂交瘤细胞高密度培养条件的研究

抗人 A 血型杂交瘤15B_4细胞在 CelliGen 细胞培养罐中进行连续灌注培养,细胞密度达1.6×10~7/ml。每天灌注新培养液量由1000ml 增到2300ml,第14天后又逐日减少至1000ml,死细胞数随着转速的增加和灌注量的减少而增多。血凝效价呈梯度上升,滴度达到2~(14),相当于腹水效价。培养6天 IgM 产量为0.2克/升/天,10～18天波动在1.45～1.8克/升/天。15B_4细胞代谢与葡萄糖、乳酸有关,与氨无关。CelliGen 自控效果较好,适用于杂交瘤细胞的高密度培养。搅拌速度在120～150r/min 对细胞产生的剪切力有明显地破坏作用。溶氧控制系统有待改进。     

The thermal performance of a Roof-Pond integrated to a building for heating during Cold-Winter Desert climate conditions in Saudi Arabia

This study reports an experiment to investigate the feasibility of a passive heating roof-pond system on an existing room in the cold winter conditions of Riyadh, Saudi Arabia. Statistical analyses of data recorded during the winter season of 1996–97, are carried out to evaluate the thermal peformance of the proposed system. Total effective heating and the heating power of the roof pond system are computed and analysed. Results indicate that the roof-pond system is capable of maintaining warm indoor air temperature conditions. The statistical formulae for this system are presented and used to estimate the indoor daily average air Dry Bulb Temperature (DBT_Avg-indoor] created by the system. Validation of the proposed formulae is also presented.     

Influence of solar wind dynamic pressure on geomagnetic Dst index during various magnetic storms

The Dst index,designed as a proxy of ring current intensity,is known to be also affected by other magnetospheric current systems,e.g.magnetopause current.The pressure-corrected Dst index is obtained by removing the effects of the solar wind dynamic pressure and the quiet time ring current.However,all previous studies treated the correction coefficient as an averaged parameter for storms of different intensity.In this paper,based on the Burton's equations and employing two independent methods,we will show a ...     

Fluid-based Slotting Optimization for Automated Order Picking System with Multiple Dispenser Types

Slotting strategy heavily influences the throughput and operational cost of automated order picking system with multiple dispenser types, which is called the complex automated order picking system (CAOPS). Existing research either focuses on one aspect of the slotting optimization problem or only considers one part of CAOPS, such as the Low-volume Dispensers, to develop corresponding slotting strategies. In order to provide a comprehensive and systemic approach, a fluid-based slotting strategy is proposed in this paper. The configuration of CAOPS is presented with specific reference to its fast-picking and restocking subsystems. Based on extended fluid model, a nonlinear mathematical programming model is developed to determine the optimal volume allotted to each stock keeping unit (SKU) in a certain mode by minimize the restocking cost of that mode. Conclusion from the allocation model is specified for the storage modules of high-volume dispensers and low-volume dispensers. Optimal allocation of storage resources in the fast-picking area of CAOPS is then discussed with the aim of identifying the optimal space of each picking mode. The SKU assignment problem referring to the total restocking cost of CAOPS is analyzed and a greedy heuristic with low time complexity is developed according to the characteristics of CAOPS. Real life application from the tobacco industry is presented in order to exemplify the proposed slotting strategy and assess the effectiveness of the developed methodology. Entry-item-quantity (EIQ) based experiential solutions and proposed-model-based near-optimal solutions are compared. The comparison results show that the proposed strategy generates a savings of over 18% referring to the total restocking cost over one-year period. The strategy proposed in this paper, which can handle the multiple dispenser types, provides a practical quantitative slotting method for CAOPS and can help picking-system-designers make slotting decisions efficiently and effectively.     

21世纪的耐火材料——动态高技术复合材料

从高技术复合材料的发展前景阐述了钙铝酸盐水泥结合浇注料和MgO-C砖这两类现代耐火材料。这些材料不仅是典型的尖端多相复合材料,而且显示了其他复合材料中难以见到的动态特性。讨论了产生这一特性的某些动力学因素。得到的结论是:当用复合材料这个术语描述这些耐火材料的某些方面时,动态特性又增加了一层复杂性。     

Relationship between Magnetomechanical Damping Capacity and Vibration Modes

The mathematical expressions for magnetomechanical damping capacity are presented by applyingSmith-Birchak's model in torsion pendulum and cantilever beam.The peak value ψ_p is found to berelated to physical parameters and material constants in the form Kλ_s=αψ_pε_p.which can be used toestimate the magnetostrictive constant λ_s from the damping capacity-strain amplitude curve.A goodagreement of experimental data and theoretical prediction was observed in HIDAMETSCr15A13NiCu.     

Growth and dielectric properties of Ta_2O_5 single crystals grown by laser heated pedestal growth technique

Ta2O5 single crystals have been grown by the laser heated pedestal growth (LHPG) technique up to several centimeters length with diameter of 1.1 mm. The crystal, characterized by X-ray diffraction, dielectric measurement, and thermal expansion analysis, has Htri-Ta2O5 symmetry. Dielectric permittivity, loss tangent along [001] and [110] direction were investigated over the temperature range from -80 ℃ to 100 ℃. Large dielectric anisotropy in Ta2O5 single crystal was observed. At room temperature, the dielectric permittivities (1 MHz) along [001] and [110] are 33.2 and 231.9, respectively. The reason of dielectric enhancement in Ta2O5 crystal grown by LHPG was also discussed.