概念设计的意义和应用分析

通过阐述结构概念设计的含义、内容、依据及其意义,并从刚度理论,材料效用,协同工作原理三方面对结构概念设计进行多角度分析,体现了概念设计的重要性,指出在结构设计中应如何考虑和运用结构概念设计思想。

Effective Utilization of Coal Fly Ash in Building Material Production

This paper is aimed at verifying utilization possibilities of alkaline modified coal fly ash as cement replacement in the concrete. The influence of alkaline activated coal fly ash originating from Slovakian power plant in Novsky （Si/Al = 3,1） as a partial cement replacement in concrete on compressive strength of hardened composites after 28 and 90 days was investigated. Alkaline activation of coal fly ash was realized in an autoclave at 130 ℃ and pressure of 160 kPa during 5 hours and in a reactor under normal conditions （equal temperature during 36 hours） at solid/liquid ratio of 0.5. Coal fly ash/cement mixtures were prepared with 25 % cement replacement by starting and modified coal fly ash and given in forms. Compressive strengths of composites after 28 and 90 days of hardening were compared to referential composite without coal fly ash and evaluated according to the standard of STN EN 450 by the value of relative strength KR （compressive strength of coal fly ash/cement composite to compressive strength of comparative concrete）. The final compressive strengths of hardened composites based on alkaline activated coal fly ash reached values in the range of 6 up to 50 MPa. In the set of experimental composites based on alkaline activated coal fly ashes, the highest value of relative strength after 28- and 90- days of hardening reached composite with cement replacement by coal fly ash zeolitized in autoclave （105% of compressive strength of referential sample）, what is connected with formation of zeolitic phases on surface of coal fly ash particles. The achieved results confirm that alkaline activation of coal fly ash in an autoclave under observed conditions can be successfully used as a partial cement replacement in concrete of C20/25 and C25/30 in accordance with requirements of standards （STN EN 450 and STN EN 206）.

Force modeling for needle insertion into soft tissue based on mechanical properties and geometric parameters

The force model during needle insertion into soft tissue is important for accurate percutaneous intervention.In this paper,a force model for needle insertion into a tissue- equivalent material is presented and a series of experiments are conducted to acquire data from needle soft- tissue interaction process.In order to build a more accurate insertion force model,the interaction force between a surgical needle and soft tissue is divided into three parts:stiffness force,friction force,and cutting force.The stiffness force is modeled on the basis of contact mechanics model.The friction force model is presented using a modified Winkler' s foundation model.The cutting force is viewed as a constant depending on a given tissue.The proposed models in the paper are established on the basis of the mechanical properties and geometric parameters of the needle and soft tissue.The experimental results illustrate that the force models are capable of predicting the needle-tissue interaction force.The force models of needle insertion can provide real-time haptic feedback for robot-assisted procedures,thereby improving the accuracy and safety of surgery.

Effective Utilization of Concrete Sludge as Soil Improvement Materials

The amount of muddy soil generated from various kinds of construction sites is always problematic. It is very difficult to treat muddy soil because of its low strength and high water content. But, the reuse of muddy soil is necessary to reduce the total amount of industrial wastes. Surplus concrete is also in a similar situation. Coarse and fine aggregates are removed from surplus concrete as an intermediate treatment, however, concrete sludge still remains. The authors propose a reuse method that involves the muddy soil being mixed with concrete sludge as an improvement material. The possibility of the utilization of concrete sludge was investigated through laboratory experiments. As a result, it was found that the unconfined compressive strength of the improved soil mixed with concrete sludge increased as the curing proceeded.

Analysis of the Power System from an Electron Beam Accelerator and the Correlation with the Theoretical Dosimetry for Radiation Processing

Dynamitron DC1500/25/04 type EBA （Electron beam accelerator）, model JOB 188, was manufactured by IBA Industrial （Radiation Dynamics, Inc.） and installed at IPEN-CNEN/SP, in 1978. The technical specifications of the EBA are： energy 0.5 to 1.5 MeV; beam current： 0.3 to 25.0 mA; beam scanning： 60 to 120 cm; beam width： 25.4 mm and frequency： 100 Hz. Nowadays, this accelerator has been used for innumerable applications, such as： For sterilization of medical, pharmaceutical and biological products, treatment of industrial and domestic effluents and sludge, preservation and disinfestations of foods and agricultural products. Other important application are lignocellulosic material irradiation as a pre-treatment to produce ethanol bio-fuel, decontamination of pesticide packing, solid residues remediation, organic compounds removal from wastewater, treatment of effluent from petroleum production units, crosslinking of foams, wires and electric cables. Electron accelerator JOB 188 is, also, very important composite and nanocomposite materials and carbon fibers irradiation, irradiated grafting ion-exchange membranes for fuel cells application, natural polymers and multilayer packages irradiation and biodegradable blends production. The energy of the electron beam is calculated as a function of the current in the accelerator high-voltage divisor, taking into account the thickness and density of the material to be irradiated. This energy is calculated considering the electron through the entire material and the distance from the titanium foil window, so that the absorbed doses at the points of entrance and exit are equivalent on the material. The dose is directly proportional to the beam current and the exposure time of the material under the electron beam and inversely proportional to the scan width. The aim of this paper is to analyze the power system parameters of the EBA Dynamitron DC 1500/25/04, such as, voltage and RMS （Root-mean-square） current in the oscillator system, high voltage generator and waveform. For this purpose software developed in the Radiation Technology Center at IPEN/CNEN-SP to simulate the energy efficiency of this industrial accelerator. Finally, it is also targeted to compare theoretical dosimetry using parameters of energy and beam current with data from the accelerator power system. This knowledge and technology will be very useful and essential for the control system upgrade of EBA, mainly Dynamitron DC 1500/25/04 taking into consideration that radiation processing technology for industrial and environmental applications has been developed and used worldwide.

Effective Use of Cement for Modification of Base Course Material

Cement improves properties of soil materials, such as durability, stiffness, strength and moisture susceptibility. Each of them needs different cement contents that might not be suitable for other properties. Typically, high cement content is desirable for durability, but not for shrinkage and cracking issues on the surface. Thus, improving durability with low cement content while complying with other requirements is an ideal aim, which may be achieved by pozzolanic supplementary products. Pozzolans contribute in hydration reactions and optimise cement consumptions in favour of durable and low shrinkage products. In this paper, the mixes of nano-silica and fly ash are considered to investigate their effect on strength, durability and shrinkage of modified CRB （crushed rock base） material. In the end, the benefits and features of nano-silica as a pozzolanic material will be focused and discussed more for effective cement consumption in soils.

Methods of Testing Seed and Seedling Physiological Traits for the Improvement of Rapeseed Yield Stability

The presented work is based on laboratory testing of seed germination speed, emergence and seedling growth under different stress conditions simulated by subnormal water revel, extreme high and low temperatures. It allows one to eliminate the plant materials （initial breeding materials and cultivars） which do not tolerate extreme temperatures and temperature changes during germination, have low water use efficiency and is intolerant to abiotic stressors all right at the seed level. It was confirmed that these genotypes also have poor t^eld emergence and initial root growth implications for further vegetation periods, mainly for over wintering and spring regeneration which has significant influence on the yield. The method also represents the tool for screening genetic resources with the resistance to the abiotic stressors and this technology process is also acceptable for other crops. The results confirm the importance of the seed and root characteristics for crop production. The deteriorating quality of soil in recent years, increasing variability of weather and long periods of drought directly support the need to intensify activities in this research. Obtained results also show the influence of seed quality characteristics on roots and above ground parts of the plant. A relationship exists also vice versa.

Enhanced photoelectric conversion efficiency of dye-sensitized solar cells by the synergetic effect of NaYF_4:Er^(3+)/Yb^(3+) and g-C_3N_4

TiO2-NaYF4：Er^3＋/Yb^3＋-C3N4 composite photoanodes were successfully designed for the first time. The photoelectric conversion efficiency of TiO2-NaYF4：Er^3＋/Yb^3＋ C3N4 composite cell can result an efficiency of 7.37%, which is higher than those of pure TiO2 cell and TiO2-C3N4 composite cell. The enhancement of the efficiency can be attributed to the synergetic effect of NaYF4：Er^3＋/Yb^3＋ and C3N4. Elec- trochemical impedance spectroscopy analysis revealed that the interfacial resistance of the TiO2-dyelI3^-/I^- electrolyte interface of TiO2-NaYF4：Er^3＋/Yb^3＋-C3N4 composites cell was much smaller than that of pure TiO2 cell. In addition, the TiO2-NaYF4：Er^3＋/Yb^3＋-C3N4 composite cell had longer electron recombination time and shorter electron transport time than that of pure TiO2 cell.

Three dimensional carbon substrate materials for electrolysis of water

Water splitting is an important approach for energy conversion to obtain hydrogen and oxygen. Apart from solar water splitting, electrochemical method plays a key role in the booming field, and it is urgent to develop novel and efficient catalysts to accelerate water splitting reaction. Recently, newly emerging self-supported materials, especially three dimensional（3D） carbon substrate electrochemical catalysts, have attracted great attention benefiting from their fantastic catalytic performances, such as large surface area,enhanced conductivity, tunable porosity, and so on. This review summarizes the outstanding materials used for hydrogen evolution reaction and oxygen evolution reaction. And catalysts that acted as both anode and cathode in two-electrode systems for overall water splitting are introduced systematically. The opportunities and challenges of 3D carbon substrate materials for electrochemical water splitting are proposed.

A novel bone marrow targeted gadofullerene agent protect against oxidative injury in chemotherapy

Chemotherapy as an effective cancer treatment technique has been widely used in tumor therapy. However, it is still a challenge to overcome the serious side effects of chemotherapy, especially for its myelotoxicity. Here we report a novel strategy using the water soluble gadofullerene nanocrystals（GFNCs） to protect against chemotherapy injury in hepatocarcinoma bearing mice, which was induced by the commonly chemotherapeutic agent cyclophosphamide（CTX）.The GFNCs were revealed to specifically accumulate in the bone marrow after intravenously injecting to mice and they exhibited excellent radical scavenging function, resulting in a prominent increase of mice blood cells and pathological improvements of the primary organs in the GFNCs（15 mg kg-（-1））treated mice after the CTX（60 mg kg-（-1）） therapy. Moreover,the GFNCs maintained and even strengthened the antineoplastic activity of the CTX agent. Therefore, the GFNCs would be the promising chemoprotective agents in chemotherapy based on their high efficiency, low toxicity and metabolizable property.

Ultrathin lanthanide oxides nanomaterials： synthesis, properties and applications

Over the past decade, ultrathin lanthanide oxides （Ln2O3, Ln = La to Lu） nanomaterials have been intensively studied in the fields of rare earth materials science. This unique class of nanomaterials has shown many unprecedented properties （big surface area, high surface effect, physical and chemical activities） and is thus being explored for numerous promising applications. In this review, a brief introduction of ultrathin Ln2O3 nanomaterials was given and their unique advantages were highlighted. Then, the typical synthetic methodologies were summarized and compared （thermal decomposition, solvothermal, soft template, co-precipition and microwave etc.）. Due to the high surface effect, some promising applications of ultmthin Ln203 nanomaterials, such as drug delivery and catalysis of CO oxidation, were reviewed. Finally, on the basis of current achievements on ultrathin Ln203 nanomaterials, personal perspectives and challenges on future research directions were proposed.

Effect of treatment process on consolidation efficiency of fugitive dust cemented by bio-activated cementitious material based on CO2 capture

As a new green and environmental material, bio-activated cementitious material is attracting extensive attention. This study confirmed that the bio-activated cementitious material could mineralize and cement fugitive dust into the cal- cite-consolidation-layer based on CO2 capture and utilization. The results illustrated that treatment processes （non-pressure spraying, pressure spraying, non-pressure blending and pressure blending） had a strong effect on the microstructure and prop- erties of calcite-consolidation-layer. According to the analysis of X-ray diffraction （XRD） and Fourier transform infrared （FTIR）, calcite was prepared by bio-activated cementitious material during the cementation process. Meanwhile, scanning electron microscopy （SEM） and thermogravimetric-differenfial scanning calorimetry （TG-DSC） were adopted to measure the corresponding variation of porous characteristics and calcite content caused by different treatment processes. The results indi- cated that the microstructure of calcite-consolidation-layer from the spraying process had lower porosity and higher content of calcite than from blending processes. In addition, the mechanical properties of calcite-consolidation-layer were also tested. The hardness and compressive strength, which reached 19.5 GPa and 0.6 MPa, respectively, of calcite-consolidation-layer from the pressure spraying process were higher than those from the other three treatment processes. Compared with the non-treatment process, the four treatment processes had superior wind erosion resistance. Under the wind speed of 12 m/s, the mass loss of calcite-consolidation-layer from the pressure spraying process decreased from 2150.2 to 23.8 g/（m^2 h）.