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1.
China has begun its standardization process in the cultural heritage since 1960.The standards contributed a lot to the development of the heritage conservation practices. In this paper, the author summaries the existing condition of standardization in the cultural heritages and museums field in China, and presents Standards for the Classification of Collected Cultural Heritages. Also this paper points out the problems which exist in the standardization in the cultural heritage, and gives the advice to solve these problems.  相似文献   

2.
What happened in 1953? The Big Flood in the Netherlands in retrospect   总被引:1,自引:0,他引:1  
During the weekend of Saturday 31 January to Sunday 1 February 1953, a storm tide raged across the northwest European shelf and flooded the low-lying coastal areas of the countries around the North Sea. The peak high waters occurred during the night and the storm surprised many people in their sleep. The resulting disaster in terms of loss of life and damage to infrastructure was enormous. In the Netherlands, 1836 people fell victim to the flood; in the UK and Belgium, the casualties were 307 and 22, respectively. The large number of fatalities in the Netherlands was related to the fact that much of the affected area is below sea-level.This paper focuses on the case of the Netherlands. It discusses the history of land reclamation, and the fact that living in low-lying areas protected by dykes, often below sea-level, is an accepted fact of life in the Netherlands. The historical approach to dyke maintenance is then outlined, and the state of the dykes in the early twentieth century and after the war is discussed. The characteristics of the storm and the flood are discussed, along with people's experiences of the first hours and days following the flood. The impact of this human stress has often been lasting--many survivors continue to live with daily memories of the flood. Attention is given to the large-scale rescue and relief efforts, the closure of the dykes during the following nine months and the concept of the Delta Plan, designed to prevent such a large-scale disaster ever happening again. Although the 1953 storm was indeed a low probability event leading to very high storm-induced water-levels, and occurred in combination with spring tide, several arguments are presented that explain why this flood turned into a disaster of such a large scale. Equally, the question is raised whether the disaster could have been prevented. The paper concludes by noting the importance of awareness and preparedness in order to prevent a future storm threat of this scale turning into a disaster of the scope of the Big Flood of 1953.  相似文献   

3.
Nucleotomy is a common surgical procedure to treat disc herniations. The potential occurrence of segmental instability after surgery, however, is suspected to necessitate re-operation and fusion. Although in vitro studies support the theory of destabilization after nucleotomy, a prior, in-house animal study contrarily revealed an increase in stability after surgery. To identify which structural compartment of the motion segment is decisive for increased stability after nucleotomy in vivo, the flexibilities of ovine motion segments were measured after different stepwise reductions at the anterior and posterior spinal column. Different test groups were used in which nucleotomy had been performed during surgery in vivo and under isolated in vitro conditions, respectively. In accordance with expectations, in vitro nucleotomy on ovine motion segments significantly increased flexibility. By contrast, nucleotomy significantly decreased flexibility 12 weeks after surgery. After removal of the posterior structures, however, the differences in flexibility diminished. The present results thus suggest that it might not exclusively be the trauma to the intervertebral disc during surgery which is decisive for post-operative stability, but rather adaptive mechanisms in the posterior structures. Therefore, care should be taken to minimize the damage to the posterior structures in the course of the surgical approach, which more likely compromises stability.  相似文献   

4.
The facts that most tissues or organs consist of a variety of cells suggest that interactions between different types of cells play critical roles in tissue or organ development.In tissue engineering,the effects of biomaterials on cell-cell interactions have recently attracted increasing attention for better elucidating the mechanisms through which biomaterials promote tissue regeneration.Numerous studies have focused on these effects of biomaterials on cell-cell interactions.In this review,comprehensive information was provided about the existing cell co-culture technologies and the main behavioral modes of cell-cell interactions.The effects of biomaterials on the cell-cell interactions in various types of tissue regeneration have been summarized and discussed.In the end,the existing problems and future perspectives that would help promote the research of biomaterials in tissue engineering have been proposed.This article can help researchers to understand the progress and importance of studying the effects of biomaterials on cell-cell interactions in tissue engineering and to choose the optimal cell-cell co-culture models for designing experiments.  相似文献   

5.
phuket,来自马来语中的“bukit”,即为小山的意思。那里有布满白色细纱的海岸线,被茂盛的红树林覆盖的东部海岸, 北部蔓延到南部将整个岛屿划分为两部分的小型山脉。在湿润的雨季来临时,直倾下来的瀑布的水流淌入斜坡上的岩石池里,秀丽壮观。 phuket拥有温季、雨季和热季。众所周知温季的phuket可以称为人间天堂,但是Dave没有选择那个美丽的季节,而在这个最让人难以忍耐的热季前往,他是为了得到什么呢?  相似文献   

6.
Solutions of metals in molten salts present a rich phenomenology: localisatlon of electrons in disordered ionic media, activated electron transport increasing with metal concentration towards a nonmetal-metal (NM-M) transition, and liquid-liquid phase separation. A brief review of progress in the study of these systems is given in this article, with main focus on the NM-M transition. After recalling the known NM-M behaviour of the component elements in the case of expanded fluid alkali metals and mercury and of solid halogens under pressure, the article focuses on liquid metal-molten salt solutions and traces the different NM-M behaviours of the alkalis in their halides and of metals added to polyvalent metal halides.  相似文献   

7.
The contents of rare earth metals(REM) insolid solution in 16 Mn steel were determined bymeans of inductive coupling plasma (ICP)spectroscopy.The amount of REM in solid solutionis only a few ppm in the steel with MnS inclusions,which rises slightly with the increasing of REMcontent in steel.At RE/S>1.9,the MnS inclu-sions in steel disappear completely,the REM con-tent in solid solution increases rapidly with the in-creasing of REM content.The solubility of ceriumin 16 Mn steel(st 52)is less than 0.011 wt—% atroom temperature.The results obtained indicate that REM in sol-id solution reduce the amount of pearlite and in-crease that of ferrite and its microhardness.Dis-solved REM oculd increase temperature of criticalpoints,alleviate band structnre and suppressgrowth of austenite grains.  相似文献   

8.
Scaffold design remains a main challenge in tissue engineering due to the large number of requirements that need to be met in order to create functional tissues in vivo. Computer simulations of tissue differentiation within scaffolds could serve as a powerful tool in elucidating the design requirements for scaffolds in tissue engineering. In this study, a lattice-based model of a 3D porous scaffold construct derived from micro CT and a mechano-biological simulation of a bone chamber experiment were combined to investigate the effect of scaffold stiffness on tissue differentiation inside the chamber. The results indicate that higher scaffold stiffness, holding pore structure constant, enhances bone formation. This study demonstrates that a lattice approach is very suitable for modelling scaffolds in mechano-biological simulations, since it can accurately represent the micro-porous geometries of scaffolds in a 3D environment and reduce computational costs at the same time.  相似文献   

9.
10.
 After nearly 100 years of aluminum production with the Hall-Héroult cell, major innovations are being considered, mainly in the materials of construction and the electrodes. This article presents a brief review of some of the innovations made in anode materials. Such improvements lead to better cell efficiencies and environmental benefits; and open the door for improved cell designs hithertofore not possible with available cell materials. Received: 17 November 1998 / Accepted: 19 March 1999  相似文献   

11.
Thermodynamic analysis for the formation of bainitic ferrite in carbon -depleted region has been conducted. The results show that the driving force of bainitic formation increases with depleting of carbon in parent austenite and with decreasing the transformation temperature. The critical driving force (absolute value) at the Bs temperature is 600-1 200 J / mol, which increases as the mean carbon content of Fe-C alloys increases. The freshly-formed bainitic ferrite has partial supersaturation of carbon, which increases smoothly with decreasing the transformation temperature Therefore, the displacive formation of bainitic ferrite in carbon-depleted region is thermodynamically feasible in the whole temperature range of bainitic reaction.  相似文献   

12.
13.
The aim of this study was to develop Cyclosporin A (CsA) sustained-release pellets which could maintain CsA blood concentration within the therapeutic window throughout dosing interval and to investigate the in vitro–in vivo correlation (IVIVC) in beagle dogs. The CsA sustained-release pellets (CsA pellets) were prepared by a double coating method and characterized in vitro as well as in vivo. Consequently, the CsA pellets obtained were spherical in shape, with a desirable drug loading (7.18?±?0.17?g/100?g), good stability and showed a sustained-release effect. The Cmax, Tmax and AUC0–24 of CsA pellets from the in vivo pharmacokinetics evaluation was 268.22?±?15.99?ng/ml, 6?±?0?h and 3205.00?±?149.55?ng·h/ml, respectively. Compared with Neoral®, CsA pellets significantly prolonged the duration of action, reduced the peak blood concentration and could maintain a relatively high concentration level till 24?h. The relative bioavailability of CsA pellets was 125.68?±?5.37% that of Neoral®. Moreover, there was a good correlation between the in vitro dissolution and in vivo absorption of the pellets. In conclusion, CsA pellets which could ensure a constant systemic blood concentration within the therapeutic window for 24?h were prepared successfully. Meanwhile, this formulation possessed a good IVIVC.  相似文献   

14.
China first Administrative Regulations for Waste Household Appliances and Electronic Products Recycling drafted by National Development and Reform Commission is currently under process of examination and approval, which is expected to be officially promulgated for mandatory implementation in early 2007. The drafting version of the Regulations specifies that household electric appliance distributors and after-service institutions have obligation to recycle waste household appliances. Where a distributor or after-service institution doesn't accept manufacture's consignment or refuse to accept waste appliance returned by consumers, or fails to hand over the accepted waste appliances to appropriate manufactures for treatment, the maximal penalty up to RMB100,000 can be applied to above said violations. Promulgation of the Regulation also means the end of the disorder of waste electronics recycling business.  相似文献   

15.
1.IntroductionSince the biginning of 1960s,the effectof Mg upon superalloy has been studiedand some satisfactory developments havebeen achieved.The role of Mg on the alloycan be summarized as follows:(1)Themechanical plasticity of Ni-base superalloycan be improved by adding Mg asdesulphurizer,because of forming insolubleMgS instead of other low melting eutectic  相似文献   

16.
Spintronics,exploiting the spin degree of electrons as the information vector,is an attractive field for implementing the beyond Complemetary metal-oxide-semiconductor(CMOS)devices.Recently,two-dimensional(2D)materials have been drawing tremendous attention in spintronics owing to their distinctive spin-dependent properties,such as the ultralong spin relaxation time of graphene and the spin-valley locking of transition metal dichalcogenides.Moreover,the related heterostructures provide an unprecedented probability of combining the di erent characteristics via proximity e ect,which could remedy the limitation of individual 2D materials.Hence,the proximity engineering has been growing extremely fast and has made significant achievements in the spin injection and manipulation.Nevertheless,there are still challenges toward practical application;for example,the mechanism of spin relaxation in 2D materials is unclear,and the high-effciency spin gating is not yet achieved.In this review,we focus on 2D materials and related heterostructures to systematically summarize the progress of the spin injection,transport,manipulation,and application for information storage and processing.We also highlight the current challenges and future perspectives on the studies of spintronic devices based on 2D materials.  相似文献   

17.
A new model of multi-range fractals is proposed to explain the experimental results observed on thefractal dimensions of the fracture surfaces in materials.The relationship of multi-range fractals withmulti-scaling fractals has been also discussed.  相似文献   

18.
Fracture profile roughnesses and fractal dimensionsof fracture traces were measured on a fatigued Ti-6Al-4Valloy.It is found that although fractal dimension can wellreflect the variation of fracture traces with the measuringunits,it is difficult to apply it to quantitative analysis offractured surfaces because of the dependence of the meas-ured profile roughness on the measuring units.Based onfractal concept.an alternative equationlgR_l(η)=lgR_o-(D-1)lgη was obtained.in which we intro-duced a parameter of intrinsic profile roughness to evalu-ate fracture profile roughness without restriction of themeasuring units employed.  相似文献   

19.
Recrystallization has been studied in brass in order to evaluate the influence of order on the recrystallization process. Recrystallization takes place by the formation of new grains at shear band — grain boundary intersections followed by grain growth and coalescence. Recrystallization occurs most readily at temperatures near the critical ordering temperature where the alloy has partial or short-range order and this is because both new grain formation and grain growth are fastest. Dislocation recovery processes are more difficult within the partially ordered materials and a larger strain energy is retained to drive recrystallization.  相似文献   

20.
Crashes between pedestrians and motor vehicles are an important traffic safety concern. This paper explores the assignment of fault in such crashes, where observed factors are associated with pedestrian at fault, driver at fault, or both at fault. The analysis is based on police reported crash data for 1997 through 2000 in North Carolina, U.S.A.The results show that pedestrians are found at fault in 59% of the crashes, drivers in 32%, and both are found at fault in 9%. The results indicate drivers need to take greater notice of pedestrians when drivers are turning, merging, and backing up as these are some of the prime factors associated with the driver being found at fault in a crash.Pedestrians must apply greater caution when crossing streets, waiting to cross, and when walking along roads, as these are correlated with pedestrians being found at fault. The results suggest a need for campaigns focused on positively affecting pedestrian street-crossing behavior in combination with added jaywalking enforcement. The results also indicate that campaigns to increase the use of pedestrian visibility improvements at night can have a significant positive impact on traffic safety. Intoxication is a concern and the results show that it is not only driver intoxication that is affecting safety, but also pedestrian intoxication.The findings show in combination with other research in the field, that results from traffic safety studies are not necessarily transferable between distant geographic locations, and that location-specific safety research needs to take place. It is also important to further study the specific effects of the design of the pedestrian environment on safety, e.g. crosswalk spacing, signal timings, etc., which together may affect pedestrian safety and pedestrian behavior.  相似文献   

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