谈室内设计中的平材新用

材料与各行各业的设计工作有着密切的联系。科技的进步,技术的提高,审美的变更,让各种材料不断推陈出新。现今,随着人们生活空间形式的改变、创新,室内装饰材料作为设计的表现手法之一一直颇受关注。在材料的使用手法上,平材新用是值得探索研究的一个创新途径,它不仅能探索出材料的创新用法,更能巧妙地从一个侧面展现设计创新。

Theoretical analysis of ultra-short pulsed laser ablation of SiO_2 material based on a Coulomb explosion model

Based on the kinetic theoretical Vlasov-Poisson equation, a surface Coulomb explosion model of SiO2 material induced by ultra-short pulsed laser radiation is established. The non-equilibrium free electron distribution resulting from the two mechanisms of multi-photon ionization and avalanche ionization is computed. A quantitative analysis is given to describe the Coulomb explosion induced by the self-consistent electric field, and the impact of the parameters of laser pulses on the surface ablation is also discussed. The results show that the electron relaxation time is not constant, but it is related to the microscopic state of the electrons, so the relaxation time approximation is not available on the femtosecond time scale. The ablation depths computed by the theoretical model are in good agreement with the experimental results in the range of pulse durations from 0 to 1 ps.

Effect of stress level on fatigue behavior of 2D C/C composites

Laminated carbon fiber clothes were infiltrated to prepare carbon fiber reinforced pyrolytic carbon （C/C） using isothermal chemical vapor infiltration （CVI）. The bending fatigue behavior of the infiltrated C/C composites was tested under two different stress levels. The residual strength and modulus of all fatigued samples were tested to investigate the effect of maximum stress level on fatigue behavior of C/C composites. The microstructure and damage mechanism were also investigated. The results showed that the residual strength and modulus of fatigued samples were improved. High stress level is more effective to increase the modulus. And for the increase of flexural strength, high stress level is more effective only in low cycles. The fatigue loading weakens the bonding between the matrix and fiber, and then affects the damage propagation pathway, and increases the energy consumption. So the properties of C/C composites are improved.

Horizontal continuous casting process under electromagnetic field for preparing AA3003/AA4045 clad composite hollow billets

A modified horizontal continuous casting process under the electromagnetic field was proposed for preparing AA3003/ AA4045 clad composite hollow billets. To investigate the effect of electromagnetic field on this process, a comprehensive three-dimensional model was developed. Two cases with and without electromagnetic field were compared using the simulations. When rotating electromagnetic stirring is applied, the flow pattern of fluid melt is greatly modified; the mushy zone becomes much wider, the temperature profile becomes more uniform, and the solid fraction decreases for both the external and internal alloy melt layers. These modifications are beneficial for the formation of a bimetal interface and fine and uniform grain structure of the clad composite hollow billet. Experiments conducted using the same electrical and casting parameters as the simulations verify that under the electromagnetic field the microstructure of the clad composite hollow billet becomes fine and the diffusion of the elements at the interface is promoted.

ANALYTICAL SOLUTIONS FOR A MODE Ⅲ CRACK IN PIEZOELECTRIC MATERIALS

A mode Ⅲ crack problem in a transversely isotropic piezoelectric material subjected to uniform loads at infinity is studied based on exact boundary conditions. The complex potential approach is used to reduce the problem to Hilbert problem. As a result, closed form field solutions in the piezoelectric material and inside the crack are presented. It is shown that the stresses and electric displacement have square root singularities at the crack tips, but the electric field is uniform everywhere in the material and equal to the remote applied one. It is also found that the electric displacement intensity factor depends on both material properties and the mechanical loads, but not the electric loads. Hence it may be concluded that the electric loads have no influence on the field singularities.

AN OPTICAL FIBER SENSOR TECHNIQUE BASED ON SLIGHT DISTURBANCE RADIATION LOSS OF STOCHASTIC WALL

This paper presents an optical sensor technique used in the damage evaluation which is formed by structurally integrated fiber optic reticulate sensors embedded in the composite materials. The fibers are processed by chemical method and their outsides are peeled to form particles of irregular distribution and they differ in size, so the slight disturbance range of stochastic wall are formed in fibers. According to the characteristics of power loss of waveguide mode caused by slight disturbance of stochastic wall and radiative mode transmission, the range of slight disturbance of stochastic wall may be served as the sensitive range of the sensor. On the basis of theory of slight disturbance of stochastic wall of planar optical waveguide, the relation between the corrosion time and the opposite power loss by experiments is investigated. In this paper, the measurement results of object of SIFORS are also presented. The results show that the optical sensor technique may be used in the damage evaluation of an aircraft.

Analysis of developing non-timber forest products of Sanjiang Plain, Northeast China

The Sanjiang Plain is a vast area of alluvial floodplains and low hills in northeast Heilongjiang Province. Because of the excessive land reclamation in the past, the whole forest area and the quality have decreased. In the view of sustainable development, this paper analyzed the possibilities for Non-timber Forest Product in terms of developing potentialities, markets, social effects and the status of NTFPs in several counties of Sanjiang Plain. The result showed that, active development and management for NTFPs is an optimistic option to how to balance the wetlands conservation and sustainable economic development.

职业教育教学探析

我是一名在教学一线工作的专任教师,本人认为教学模式及教学方法应该与时俱进,首先我认为应该强调每一个老师要从单纯注重传授知识转变为引导学生学会学习,学会合作,学会做人。其次要着重培养学生具有社会责任感、实践能力和良好的综合素养等。第三要关注学生思想品德等多方面的发展。

Numerical investigation on freeze-drying of aqueous material frozen with pre-built pores

Freeze-drying of the initially porous frozen material with pre-built pores from liquid material was found experimentally to save drying time by over 30% with an initial saturation being 0.28 compared with the conventional operation with the initial saturation being 1, using mannitol as the solid material. In order to understand the mass and heat transfer phenomena of this novel process, a two-dimensional mathematical model of coupled mass and heat transfer was derived with reference to the cylindrical coordinate system. Three adsorption–desorption equilibrium relationships between the vapour pressure and saturation value namely, power-law, Redhead's style and Kelvin's style equation, were tested. Kelvin's style in exponential form of adsorption equilibrium relation gave an excellent agreement between the model prediction and experimental measurement when the equation parameter, γ, of 5000 was applied. Analyses of temperature and ice saturation profiles show that additional heat needs to be supplied to increase the sample temperature in order to promote the desorption process. Simulation also shows that there is a threshold initial porosity after which the drying time decreased with the increase in the initial porosity. Enhanced freeze-drying is expected to be achieved by simultaneously enhancing mass and heat transfer of the process.

Stability of boundary pillars in transition from open pit to underground mining

Based on the height of back-filled materials, thickness of ore body, height of boundary pillar and dipping angle of ore body and water pressure, the safety factors of all the pillars are calculated with the limit equilibrium method. The calculation results present that the safety factors of pillars in Sections 19, 20, 24, 28 are less than 1.3, and those of unstable sections are identified preliminarily. Further, a numerical investigation in Sections 18, 20, 22, 24, 25 and 28 implemented with numerical code RFPA20 is employed to further validate the pillar performance and the stability of stopes. The numerical results show the pillars in Sections 18, 22 and 24 are stable and the designed pillar size is suitable. The width of the ore body near Section 28 averages 20 m, failure occurs in the left stope, but the boundary pillars near Section 28 maintain good performance. The pillars in Sections 20 and 25 are unstable which are mainly affected by the Faults F8 and F18. The existence of faults alters the stress distribution, failure mode and water inrush pathway. This work provides a meaningful standard for boundary pillar and stope design in a mine as it transitions from an open pit to underground.

The Research to Quality Supervision and Management of Power Enterprises

Intensive in-depth development of resources, centralized purchasing and gradually expand under the category of environment, this paper studies how to use information technology tools to construction quality supervision and management system that focuses on the quality of supervision and project management, quality control process management, quality monitoring statistics report management, platform management-related content in four areas. Through the construction quality supervision and management system, to better enhance the quality of electric power enterprise management level, to ensure that the material quality, quantity of time and supplies. strengthening quality supervision and management can not only effectively reduce material procurement costs, but also enhance the competitiveness of enterprises.

A new patch antenna with metamaterial cover

A metamaterial was introduced into the cover of a patch antenna and its band structure was analyzed. The metama- terial cover with correct selection of the working frequency increases by 9.14 dB the patch antenna’s directivity. The mechanism of metamaterial cover is completely different from that of a photonic bandgap cover. The mechanism of the metamaterial cover, the number of the cover’s layers, and the distance between the layers, were analyzed in detail. The results showed that the metamaterial cover, which works like a lens, could effectively improve the patch antenna’s directivity. The physical reasons for the improvement are also given.

Evaluation of in-plane shear test methods for composite material laminates

In-plane shear properties of composite material laminates are very important in structural design of composite material. Four commonly used in-plane shear test methods were introduced in this paper. In order to study the differences of various shear test methods, two ASTM standard in-plane shear test methods for composite material laminates were experimentally investigated. They are ±45° tensile shear test (ASTM D3518) and V-notched rail shear test (ASTM D7078). Five types of composite material laminates composed of E-glass fiber fabric and vinyl ester resin were utilized, whose stacking sequences are 03s, 0/903s, CSM/0/902s, ±453s and (0/90)2/(±45)2/(0/90)2s, respectively. The test results indicate that the ±45° tensile shear test can predict shear moduli of composite material laminates accurately. However, the predictions of shear strength using ±45° tensile shear test are significantly lower than those of V-notched rail shear test.

Lean Healthy Children with Short Stature Have Distinct Eating Patterns

Nutrition plays an essential role in normal linear growth in children. Knowledge of the eating styles and dietary consumption of healthy short children from developed countries is scarce. The aim of this study was to investigate the dietary patterns in idiopathic short stature （ISS） and relatively low weight children compared to children with normal stature and weight. This research is a case-control study of 86 pre-pubertal healthy children, mean age 5.9 ± 1.5 years. The study group comprised 43 ISS children; 43 age-matched children with normal stature and weight served as controls. Outcome measures included： dietary patterns and physical activity. The absolute daily average energy, protein and carbohydrate intake was significantly lower in the ISS children （P 〈 0.05）; after correcting for body surface area, no significant differences were found between groups. Intake of micronutrients calcium, iron, zinc, vitamin A and vitamin C, expressed as percentage from Recommended Dietary Allowance, was significantly lower in the ISS children （P 〈 0.05）, who had lower food responsiveness, higher satiety responsiveness, lesser enjoyment of food and were slower eaters （P 〈 0.001）. Physical activity was sedentary in both the ISS cases and controls. Our findings in healthy, pre-pubertal, relatively lean ISS children point to a distinct eating pattern with no alteration in physical activity. Understanding the differences in dietary intake and eating behaviors may be beneficial in the development of targeted nutritional intervention for lean ISS children.

Autograft-prosthesis composite for aggressive giant cell tumor of bone around knee

Objective： The aim of the research was to study the clinical feasibility of autograft-prosthesis composite for aggressive giant call tumor of bone around knee. Methods： Seven patients （5 males and 2 females, the mean age of 30.5 years old） with giant cell tumor of bone around knee underwent tumor resection and reconstructed with autograft-prosthesis composites since January 2006. Five lesions located at the distal femur and 2 at the proximal tibia. There were 3 patients with primary tumor and 4 with recurrent. Three patients with pathological fracture and all patients were of Campanacci Ⅲ. Results： All patients were done follow-up from 12 to 36 months. No recurrence, metastasis, and prosthesis loosening were found. The mean healing time between autograft and host bone was 5 months. The mean motion range of affected knee were 90° （70°-110°）. Conclusion： Our data documented the clinical feasibility of autograft-prosthesis composite for giant cell tumor of bone around knee which should be performed tumor resection and reconstructed with prosthesis. The long-term outcomes remain to be further proven.

The Explicitly Covariant Stress-Energy-Momentum Balance Equation for Electromagnetism in Material Media

Beginning with the explicitly covariant Maxwell equations in media, we deduce an explicitly covariant stress-energy-momentum balance equation in material media. Proceeding in this way we avoid mixing external fields and self fields, as occurs if one begins with Lorentz＇s law, the most usual approach appearing in textbooks. Indeed our deduction implies a generalized force density in which the total fields appear. As an application of the present deduction, we discuss briefly the Abraham-Minkowski controversy, showing its relation to open or closed electromagnetic systems. This approach will be interesting for scholars as well as graduate students interested in conceptual problems of relativistic electromagnetism.

Geant4 Comparative Study of Affecting Different Parameters on Optical Photons Related to the Plastic Scintillation Detector

In this research, different parameters of plastic scintillator detector were investigated by Geant4 simulation toolkit. These parameters consisted of radius, length and position of PMT as well as surface reflective type and finish options. Furthermore, response time distributions of two organic plastic materials were studied. The results indicated that collecting optical photons has a linear relationship with PMT radius head. Also, the vertical location of PMT has a non-linear relationship with the optical photons collection. However, the collection decreased by increasing PMT length or moving PMT head horizontal position. The response functions of two plastic scintillator materials were in good agreement with experimental published results. Also, Geant4 radiation transport code can simulate incident radiation photon and predict subsequent events to the PMT head very well. The results indicated that BC-404 has faster scintillation properties versus BC-400 organic scintillator materials. Comparison between Geant4 outputs illustrates that the best reflector material and surface finish type for optical photons is ground TiO2.

Effect of electromagnetic and ultrasonic cast rolling on microstructure and properties of 1050 aluminum substrate for presensitized plate

The 1050 aluminum alloy strip was prepared by means of electromagnetic and ultrasonic cast rolling on the modified asymmetric twin roll caster, and then the aluminum substrate for presensitized plate was prepared through cold rolling and annealing.The effects of electromagnetic and ultrasonic cast rolling on microstructure, mechanical properties, surface roughness and electrolytic corrosion properties of 1050 aluminum substrate were studied. The results show that electromagnetic and ultrasonic cast rolling can decrease the average crystallite size of aluminum substrate by 5 μm, increase the crystal boundaries with uniform distribution, and make the second-phase particles with smaller size distributed dispersively in the substrate, meanwhile, it can increase the tensile strength, elongation and micro-hardness by 4.58%, 9.85% and HV 2, respectively, reduce the surface roughness, make the surface appearance more even, electrolytic corrosion polarization curve of aluminum substrate more smooth and the surface corrosion pits with regular shape more dispersive.

Impact of Planting Position and Planting Material on Root Yield of Cassava （Manihot esculenta Crantz）

Cassava （Manihot esculenta Crantz） is a perennial woody shrub with an edible root, which grows in tropical and subtropical areas of the world. In Africa, cassava provides a basic daily source of dietary energy. It plays an important role in food security and incomes of many rural households in the southern Ethiopia. However, information available on production practices of cassava for the region is insufficient. Hence, field experiment was conducted at Awassa Agricultural Research Center for two successive cropping seasons from 2004 to 2006 to investigate the response of cassava to planting position and planting material. The treatments used were three planting positions （slant, vertical and horizontal） and five planting materials （main stem top part, main stem middle part, main stem bottom part, branch stake top part and branch stake bottom part） were combined in factorial arrangement and laid out in randomized complete block design with three replications. The result revealed that root yield was significantly （P 〈 0.05） affected by the interaction effects of the planting position and planting material. The highest yield （25.2 ton ha^-1） was obtained from the main stem top part planted in slant position whereas the least yield （6.5 ton ha^-1） was obtained from main stem bottom part planted in horizontal position. Based on the findings of this study, areas like Awassa with moderate rainfall slant and vertical planting of main stem top and middle parts could be used as planting material.

Method for grinding and delaminating muscovite

A method of dry grinding muscovite based on the use of knife-mills is reported.It was possible to produce mica with a particle size below 100 and 45μm.After grinding,the samples were submitted to sonication treatment,which promoted delamination of the material.The particle size distribution shows that sonicated mica has more particles in the size range 10-50μm than does non-sonicated mica have. This also indicates a decrease in the average particle size.Characterization of the treated muscovite by scanning electron microscopy revealed a highly delaminated material with a plate-like structure.The products were characterized by chemical analysis and X-ray diffraction,too.This mica has already been used for the synthesis of pearlescent pigments.