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1.
基于疏散鸟体动能的防鸟撞策略,以提高结构刚度和抑制变形为目标,采用光滑粒子流体动力学(SPH)方法对现有飞机尾翼前缘结构鸟撞过程进行了数值研究。根据模拟结果,通过增加单向斜支板结构和采用纤维/金属复合材料,实现了从结构和材料两个方面对尾翼前缘结构进行改进设计。结果表明,前缘增加的单向斜支板结构可以通过疏散鸟体动能来降低鸟撞冲击对尾翼内部结构的破坏,而采用纤维金属复合材料则减轻了前缘曲翼约10%的质量,且提高了整体刚度,并使结构在鸟撞过程中最大变形降低到原始构型的25%。通过分析不同铺层方式下材料的破坏模式和吸能效果,发现合理的铺层设计可显著提高尾翼前缘结构的抗鸟撞性能。  相似文献   

2.
Zinc oxide has a unique position among semiconducting oxides due to its piezoelectric and transparent conducting properties. The catalyst-free synthesis of pure ZnO nanostructured material with 6-fold structural symmetry was synthesized by the chemical precipitation method. In this article, various nanostructures of ZnO which are grown by the chemical precipitation technique has been reported. Zinc oxide nanoparticles were synthesized by heating freshly prepared zinc hydroxide [Zn(OH)2] at 150℃ for two hours. The prepared compound was characterized by the X-Ray diffraction technique. Zinc oxide nanoparticles possess high removal capacity of As (III), which can easily be separated and recycled during water treatment processes.  相似文献   

3.
Carbon dioxide (CO2) adsorption is an important adsorbent characterization method and a significant industrial process. In separation and recovery technology, the adsorption of the CO2 is important to reduce the concentration of this gas considered as one of the greenhouse gases. Natural zeolites, particularly clinoptilolite, are widely applied as adsorbents. In this regard, in the present research, the structure, composition and morphology of modified with hexafluorosilicate (HFSi) and orthophosphoric acid (H3PO4) clinoptilolites were investigated by characterizations and measurements made with, X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDAX) and gravimetric adsorption. Additionally, the surface Chemistry of the modified clinoptilolites was analyzed by applying diffuse reflectance fourier transform infrared spectrometry (DRIFTS). Further, the interaction of CO2 within the adsorption space of these modified clinoptilolites and a synthetic ZSM-5 zeolite was studied with the help of adsorption measurements. After all, an appropriate theoretical methodology for the analysis of the XRD and adsorption data was applied. The calculated cell parameters of the tested are similar to those reported for a typical clinoptilolite of: a = 17.662 A, b = 17.911A, c = 7.407 ~ and fl = 116.40 The resolution of the TGA derivative profiles indicated the presence of two steps for water release, one of them represents the loss of majority of the water present in the micropores. This was evidenced as a broad peak centered at about 50℃ for the CSW-HFSi-0.1, but at 100 ℃ for the samples CSW-HFSi-0.4. The SEM micrographs corresponding to the modified clinoptilolites, was evidenced that the CSW zeolite shows secondary particles exhibiting diameters from 3 to 40 μm, formed by primary clinoptilolite crystallites showing a crystallite size, φ = 40 nm. The EDAX elemental analysis it can be demonstrated that the exchange process replaced about 85% of the charge compensating ions. The DRIFT spectra of the modified clinoptilolites, specifically, CSW-HFSi-0.1, show a narrow band at about: 3,740 cm-1 corresponding to terminal silanol groups (Si-OH) and a band 3,600-3,650 cm1 resulting from extra-framework AI-OH. With the precision of the measured micropore volumes related to the excellent fitting of the adsorption data by the D-R isotherm equation, it can be affirm that carbon adsorption took only place in the micropore region. The isosteric heat of adsorption calculated for the modified clinoptilolites was greater than those values reported of ZSM-5 zeolite, particle packing silica, dealuminated Y zeolite (DAY) Cd, Zn and Ni-nitroprussides and Cu-nitroprusside and a Ni-MOF. With the obtained result it can be concluded that the modified clinoptilolites with HFSi showed a quality as adsorbent comparable to commercial synthetic zeolites.  相似文献   

4.
The present study relates to the use of cyanobaeterium Nostoc linkia for removal of chromium and nickel from wastewater of galvanic industry. To determine concentrations of Cr and Ni in wastewater samples atomic absorption spectrometry was used. The samples of dried nostoc biomass after exposure to wastewater were subject to nondestructive instrumental neutron activation analysis. During 30 rain of the contact ofbiomass with wastewater 84% of chromium was removed from the wastewaters. Beside chromium after 30 rain nostoc biomass accumulates the amount of iron and zinc that exceeds their concentrations in the control biomass samples by a factor of 6 and 8, respectively. Nickel content in biomass after interaction with Cr-containing wastewater increases sixty fold and copper-sixteen fold. During the same time of biomass-Ni-containing wastewater interaction, 50% of nickel were accumulated. The method of Fourier transform infrared spectroscopy was applied to identify functional groups responsible for metal binding.  相似文献   

5.
The paper deals with the theoretical and practical aspects of improving regulatory and technical framework for assuring the quality and safety of metal structures and their protective coatings under the exposure of corrosive environment. Methodological approach has been developed to managing technological safety, assessing the risks of corrosion failures, and extension of an industrial facility's life based on company standards taking into account the requirements for safe operation of buildings and installations. Basic provisions of the method of limit states design have been analyzed to determine: design characteristics of corrosion impacts, computational models and design cases for affirming compliance of corrosion resistance, and durability and maintainability of structures and their protective coatings. Presented are practical examples of justifying the choice of means of primary and secondary protection, taking into account classification of the established levels of facility corrosion hazard. On the basis of limit state design principles, logistical control- and decision-making system is generated for reliability assurance of steel structures and protective coatings. Assessment criteria are specified for the risks with the use of the materials and technologies of primary and secondary corrosion protection.  相似文献   

6.
The contribution deals with preparation of C50 fullerene derivatives (oxo derivative, bromo derivative, hydrolyzed bromoderivative, bromo-chloro derivative), their identification and pilot testing of their biological effects on unicellular organisms. The contribution describes effects of C60 fullerene derivatives, both on prokaryotic organisms (bacteria, cyanobacteria) and eukaryotic organisms (algae) and assesses their potential use as biocides.  相似文献   

7.
This article is devoted to research of surface active additive, acrylic reagent of the "Nakphlok" in the process of galvanic coating obtainment. It was proved that the copper coating obtained in the presence of electrolyte additives Nakphlok-C are of high quality.  相似文献   

8.
This paper describes one anthropomorphic modular reconfigurable gripper for robots, including a prototype and one command solution. For the first time the stages of synthesis, analysis design and functional simulation are presented. The structural synthesis of the anthropomorphic grippers for robots can be made regarding the following main criteria: the number of fingers, the number of phalanxes, the relative dimensions of the phalanxes, the relative position of the fingers, the degree of freedom of the gripping mechanism and the characteristic constructive elements used. We have chosen a version with three identical fingers with three phalanxes on finger. The kinematic synthesis is used to obtain a correct closing of the finger and of the gripping mechanism. The static synthesis solves the problem to obtaining the necessary gripping force on each finger and the total gripping force. With the constructive dimensions a 3D model can be obtained using CATIA soft. Aspects regarding functional CAD and virtual simulations are shown too. For one variant of this type of gripper, the technical documentation is completed and the technical project has all the conditions for practical achievement and a prototype was made. There are two main constructive modules: the support, the palm and the finger. Main technical characteristics of the prototype are indicated. Some aspects regarding actuated and command schemes are shown.  相似文献   

9.
The physical model of cell ratio object is used for calculation of additional magnetic fields caused by the interaction of magnatic moments. There have been calculated the additional magnetic fields caused by the interaction of magnetic moments. The spatial density reconstruction of the modeled object with additional magnetic fields was obtained by MRI. The pseudo-inversion matrix method is used for spatial density reconstruction of investigated object. The calculation of additional magnetic fields while reconstruction of small objects gives more precise and full information about investigated objects.  相似文献   

10.
This study investigates the microstructure of the processed cassava leaves. Standard parts machined from low visible diffusion zone formed in low carbon steel pack cyanided using carbon steel were pack cyanided by high temperature in-situ diffusion of nascent carbon and nitrogen into austenite. Formation of a visible diffusion zone was confirmed after observation with a Reichert-Jung Polyval optical microscope coupled with Zeiss AxioCam ICc 1 camera. High magnification Scanning Electron Microscope (SEM) imaging of the visible diffusion zone was done with a CamScan Series 2 scanning electron microscope. The zone was found variable in depth as measured from a representative position. The structure of all samples consists of ferrite and pearlite as determined by optical and SEM examination. Resulting products were thus both tough and hard suitable for service environments requiring high resistance to both wear and impact failure.  相似文献   

11.
The purpose of our study was to show if there is any correlation between the location of the primary cancer site in the lungs, and the appearance of metastases in the spleen. 1,998 patients with confirmed lung cancer were analyzed. In 22 out of 22 cases, splenic lesions were detected by both, computer tomography (CT) and ultrasound (US) in all 22 of them. All patients with splenic lesions detected by the US underwent US-guided biopsy. Among these patients, metastases to the spleen were histopathologically confirmed in all 22 cases. 18 metastases in the spleen originated from left lung tumors, 3 from right lung tumor. In the 1 case remaining, a pattern of benign lesion was confirmed. The authors came to the conclusion that lung cancer metastases detected in the spleen originate mainly from the left lung cancer which can be caused by higher blood flow to the left lung as compared to the right lung.  相似文献   

12.
In a context of sustainable development and use of eco- materials, it was examined the possibility of using sewage sludge from the water treatment plant of Ziga as an inorganic support to achieve sealing barriers that can withstand high stresses to overcome any weaknesses of the geological barrier (called passive barrier). The station Ziga that potabilises the water from the river Nakamb6 is located 45 km north east of Ouagadougou. Some experiments on the rheology of sludge from Ziga as well as the filtration of the mixture Ziga's sludge and clays from Nouna, Zorgho and Ticare, three regions of Burkina Faso, were conducted. These studies demonstrated the complex hydro-mechanical behavior of Ziga's slurries: Newtonian fluid thixotropic threshold for solids contents less than 16.5 wt% and non-Newtonian for higher values. Sludge from the water treatment station Ziga have a hydraulic conductivity of 10^-8 m/s. The results are below regulatory requirements. However, the permeability can be reduced to achieve the value of 10^-9 m/s in particular by adding the clay from Zorgho or Nouna to mixtures of Ziga's sludge and neutral leachate, typically mineral water. Beside neutral leachate, two types of leachate were used. One type is composed of acid leachate and the other type is basic. It was shown that the limewater solutions cause deterioration of the seal probably due to the presence of hydroxide ions.  相似文献   

13.
Ethephon or gas stimulation application is a common practice in rubber cultivation especially in commercial estates. The use of stimulation can be combined with reduction in the intensity of tapping by reducting of cut length. The purpose of this study was to compare and to evaluate the effect of various tapping systems on production and physiology characters from opening. The experiment was carried out in the experimental field of Sembawa Research Centre since March until December 2011. The experimental design was the Completely Randomized Block Design with 6 treatments and 8 replication. The experiment used RRIC 100 clone planted in 2004. The treatments were S/2 d3, S/2 d3 ET2.5% Gal 12/y (m), S/2 d3 ET2.5% Gal 24/y (2w), Sc20 U d3 ETG 12/y(m), Sc20 U d3 ETG 24/y(m), and Sc20 U d3 ET2.5% Bal 24/y(2w). The results showed that the tapping system of S/2 d3 ET2.5% Gal 12/y (m) or Sc20 U d3 ETG 12/y(m) can increase production without negative effect on physiology parameters. However, application of gas stimulation on young trees should be used with consideration for the risk of tapping panel dryness. Since the upward tapping tends to result in a thicker cut and latex spillage from the groove, the tapper should be well trained.  相似文献   

14.
The paper introduces the characteristics of a new type washing machine (mini washing machine) and analyzes the global problems solved by mini washing machines from the perspective of meeting different consumers’needs. On the basis of current performance specifications of IEC 60456, it explains how to improve the performance test method of mini washing machine in details, and points out the direction of standards research and test improvement. Meanwhile, the author briefs about other new type washing machines and the developmental trend of washing machines.  相似文献   

15.
Nowadays many studies have been focusing on the development of biomaterials obtained from renewable resources to replace fossil based plastics. The famous example is starch which is produced by a wide variety of plants as energy reserve and is available in abundance at a very competitive price. It can easily be transformed into thermoplastic starch (TPS) by addition of a plasticizer. However, TPS suffers from several limitations, such as poor mechanical properties and water sensitivity which did not permit its use in large practical applications. In this study, different formulations, containing commercial corn starch and plasticizers were prepared by the film casting method, after gelatinization of starch in hot aqueous suspensions. To obtain flexible films, two plasticizers were used: glycerol and dioctyl phthalate (DOP). The fact that the DOP displayed an exceptionally poor water affinity, three co-solvents, methanol, ethanol and acetone were added in the aim to improve its solubility. The obtained materials were tested considering the water resistance measured at 25 and at 50 ℃, mechanical properties in tension and the differential scanning thermal analysis (DSC). From the obtained results, it seems that the solvent system as well as the plasticizers used affects considerably the properties of the resulting materials.  相似文献   

16.
In the present work, an array of novel substituted 2H-chromen-2-one (coumarin derivatives abbreviated as C-337, C-480, C-540A) has been subjected to photophysical analysis. Although the influence of the electron donating groups such as amino, substituted amino, hydroxyl, alkoxy groups at position 7 of the coumarin ring system has been extensively studied, However, coumarin moieties with substituent at position 3 have not been explored much. Attempt is made to explain the effect of electron donating and electron accepting substituent on excited state and ground state dipole moment. The ground state (μ) and excited state (μ*) dipole moment of C-337, C-480, C-540A coumarins are estimated from solvatochromic shift of absorption and fluorescence spectra as a function of the dielectric constant and refractive index using Bakhshiev and Kwaski-Chamma Vialletequ. μ* and μ for all the reported coumarin are also calculated using Reichardt correlation method. The small angle is also reported between the ground and excited state dipole moment suggesting that they are almost parallel to each other. Excited state dipole moment is observed larger than ground state dipole moment for all the coumarins studied indicating substantial n-electron density redistribution.  相似文献   

17.
In general, any stress inducing substance will affect the respiratory metabolism of an animal. Any alteration in the intermediary metabolism due to stress is bound to affect the activity of oxidative enzymes like lactic dehydrogenase (LDH) and succinic dehydrogenase (SDH). Both enzymes are involved in carbohydrate metabolism and have been used as an indicative criterion of exposure to chemical stress. Several authors have reported that the disturbance in the oxidative metabolism which leads to an alteration in whole oxygen consumption in different species of fishes exposed to pesticides. Carbohydrates are the primary and immediate source of energy. In stressed condition, the carbohydrate reserve (glycogen) is depleted to meet the energy demand. Depletion of glycogen may be due to the direct utilization for energy generation, a demand caused by the pesticide induced hypoxia. Similar findings have been reported in frog Rana tigrina. Glycogenolysis seems to be the result of increased secretion of catecholamines due to stress. Pesticides also inhibit energy production by suppressing aerobic oxidation of carbohydrates leading to energy crisis in animals. LDH and SDH are widely used in toxicology and clinical chemistry to diagnose the cell, tissue and organ damage. In the present study, the toxicological effect of methyl parathion on the LDH and SDH activity has been made in the fish, Cirrihinus mrigala. The study revealed that the acute toxicity (TUa) of methyl parathion was 14 ppm.  相似文献   

18.
The emergence of electroless Ni-P based ternary coatings and consequence duplex deposition possibilities, now offer more excellent corrosion and functional properties in acidic and alkaline environment. In this study, medium and high phosphorus Ni-P and duplex Ni-W-P coatings were produced and sequentially deposited on mild steel using plating baths with 10 g/L and 25 g/L of sodium hypophosphite as reducing agent (RA) with composition of the resulting deposits to be 91.5 Ni: 8.5 P and 87.6 Ni: 12.4 P, respectively. From the field-emission scanning electron microscope (FE-SEM) examination, the deposit morphology was found to change from nodular with some surface porosity to become more dense and smoother after heating treatment between 200-600 ℃. The cross-section reveals firm adhesion of the as-plated and the merging of the top duplex layers of the heat treated sample as a result of tungsten diffusion. The potentiodynamic polarization test shows that the coating demonstrated significant improvement of corrosion resistance in 3.5% NaCI solution with optimum performance at 600℃. The noted improved corrosion resistance of the coating came as a result of annealing which strengthened the layer and broaden its application.  相似文献   

19.
Hybrid inks are often used for the advertising products because a variety of effects can serve as an added value. Much attention is paid to the inks application settings, using the hybrid inks at the hi-tech offset equipment and color features of images. The thorough research of the different printing settings with the use of modern inks and efficient equipment, is an urgent problem. Work reveals some new facts about characteristics for printability such as emulsification and influences of ink's additives on color characteristics of imprints. The experimental inks were developed to define the technological settings of offset printing. The result of research showed that conventional inks have the considerably high degree of emulsification comparing to experimental hybrid inks. Also it was discovered that the UV components influence the emulsification. An optimal water-ink balance and stable printing process can be achieved with adding of 2%-10% of the UV-component to the hybrid inks. Inks application and drying settings as well as color features of the imprints are analyzed in the context of offset printing.  相似文献   

20.
Adsorptive properties of laminated material with widening structural cell are determined by dispersion, which is depends on crystalline vermiculite grid structure. Created sorbents developed porous by acid activation desirable choice minerals with an expanding structural cell. Significant role in the formation of advanced sorbent porosity is the formation of thin layers of amorphous phase between partial destruction of the elements of the original structure of vermiculite.  相似文献   

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