浅谈高层建筑发生火灾的原因与消防安全设计

随着我国经济的快速发展,高层建筑层出不穷。如何有效降低高层住宅发生火灾率,成为了一个全新的问题。基于此,本文通过对高层建筑火灾事故中暴露出的问题进行分析,对高层建筑消防安全设计进行了研究,并提出了提升高层建筑的消防安全管理工作策略,以供参考。

Vertical axis wind turbine with omni-directional-guide-vane for urban high-rise buildings

A novel shrouded wind-solar hybrid renewable energy and rain water harvester with an omni-directional-guide-vane(ODGV) for urban high-rise application is introduced.The ODGV surrounds the vertical axis wind turbine(VAWT) and enhances the VAWT performance by increasing the on-coming wind speed and guiding it to an optimum flow angle before it interacts with the rotor blades.An ODGV scaled model was built and tested in the laboratory.The experimental results show that the rotational speed of the VAWT increases by about 2 times.Simulations show that the installation of the ODGV increases the torque output of a single-bladed VAWT by 206% for tip speed ratio of 0.4.The result also reveals that higher positive torque can be achieved when the blade tangential force at all radial positions is optimized.In conclusion,the ODGV improves the power output of a VAWT and this integrated design promotes the installation of wind energy systems in urban areas.

A NOVEL PHYSICAL-LAYER TRANSCEIVER USED IN USB2.0 SERIAL DATA LINK

The paper proposes a novel transceiver in physical layer for high-speed serial data link based upon Universal Serial Bus (USB) 2.0, comprising transmitter and receiver. In the design, transmitter contains pre-and-main driver to satisfy slew rate of output data, receiver includes optimized topology to improve preci- sion of received data. The circuit simulation is based on Cadence’s spectre software and Taiwan Semiconduc- tor Manufacture Corporation’s library of 0.25μm mixed-signal Complementary Metal-Oxide Semiconductor (CMOS) model. The front and post-simulation results reveal that the transceiver designed can transmit and re- ceive high-speed data in 480Mbps, which is in agreement with USB2.0 specification. The chip of physi- cal-layer transceiver has been designed and implemented with 0.25μm standard CMOS technology.

Summary on the Harmonious Relationship between Urban Lake Landscapes and Lakeshore Architectural Image

A variety of high-rise building landscapes are trying to invade urban lakes resulting in the shrinkage, fragmentation, pollution of lakes and cut-down of vegetation along lakes. With the development of real estate along lakes, the local marginal lines and natural landscapes nearby are disappearing. How to plan urban landscapes＇？ How to achieve the harmonious relationship between lakeshore landscapes and lakeshore architectural image？ How to render lake sights an organic and sustainable whole？ How to balance the interest between economy and value for each interest group？ How to form urban lake sights and architectural images？ How to utilize and arrange the space？ How to form a harmonious relationship between the lake scenes and buildings in the city？ Through on-the-spot investigation and profound analysis of several lakes in Wuhan, applying enumeration, induction and analysis, the dissertation reveals that people need to share natural resources and get the support from laws and policies with the aim of building a beautiful home. In tmaa, people＇s anticipation is needed to achieve a harmonious relationship between landscapes and architectures.

Corporate Entrepreneurship in Pharma R＆D Organizational Transformations

This multiple-case study examined factors that could contribute to a richer understanding of top managers＇ perceptions on maintaining high-performance teams in Pharma R＆D. In addition, this multiple-case study investigated top managers＇ perceptions of building opportunity-based entrepreneurial culture in organizations during strategic change, considered as a critical factor for organizations during change, the results of which can be used to guide management in preventing destructive actions of business non-loyalty. Following, this multiple-case study examined the management of change within the corporate entrepreneurship literature as a means of helping organizations improve practical intelligence of defining growth goals and new enterprise growth management processes and procedures, including those relevant to change, the way they function, and formal and informal rules protecting adequacy of governance arrangements as well as the organizational culture. Participant responses to the interview question regarding capability to maintain high-performing teams resulted in themes regarding role of leadership in risk management approach, leadership development challenges, trust and commitment in inter-fLrm relationships, as being the top managers＇ perceptions and the attitudes in outsourcing R＆D industry sector since the enactment of the strategic change.

Fractured zone height of longwall mining and its effects on the overburden aquifers

As mining depth becomes deeper and deeper,the possibility of undermining overburden aquifers is increasing.It is very important for coal miners to undertake studies on the height of fractured zone during longwall mining and the effects of longwall mining on the underground water while mining under surface water bodies and underground aquifers.In order to study this problem,piezometers for monitoring underground water levels were installed above the longwall panels in an American coalmine.Large amounts of pre-mining,during mining and post-mining monitoring data were collected.Based on the data,the heights of fractured zones were obtained and the effects of longwall mining on the underground water were studied.The results demonstrate that when the piezometer monitoring wells had an interburden thickness of less than 72.7 m,the groundwater level decreased immediately to immeasurable levels and the wells went dry after undermining the face of longwall.The height of the fractured zone is 72.7-85.3 m in the geological and mining conditions.The results also show that the calculated values of fractured zones by the empirical formulae used in China are smaller than the actual results.Therefore,it is not always safe to use them for analyses while mining under water bodies.

Wind response of high-rise building in diversified inlets to construct wind turbine system on roof

Many skyscrapers have installed wind turbine systems to use new renewable energy. In particular, building an integrated wind power generation system by installing a wind power generator inside a building is an attractive method to secure safe energy. However, most studies have dealt with the efficiency of wind turbines and the response effects of wind induced vibration; space preparation for wind turbine installations has not been sufficiently considered. This work reviewed the shapes of openings where wind turbines can be installed in skyscrapers, and the characteristics of wind induced vibration responses occurring in the building with changes in cross sectional area. Nine wind power models were constructed to carry out the experiment. According to the experimental results, wind speed varies with shape of opening in the order of C-type>S-type>R-type. Moreover, wind speed increases as the area is reduced.

Recent Advances in the Theoretical and Applied Study on Compressible Turbulent Flow over Aerospace Vehicles

This paper focused on the fundamental and applied research of turbulent flows encountered in the hypersonic flight of aerospace vehicles,which take place in the boundary layer and mixing layer.As to the plate boundary layer,LES approach has been used to simulate the flows over compression corners and incident shock waves,revealing that turbulent flows would significantly inhibit the boundary layer separation caused by shock wave-boundary layer interaction(SWBLI).The boundary layer transition over a circular cone has been analyzed through stability analysis and wind-tunnel test,by which the angle-of-attack effect in case of small angle of attack has been studied.Non-linear evolution process and secondary instability structure in the supersonic mixing layer(Mc=0.5) were initially figured out through the study of mixing layer,and knowledge of the flow control mechanism of the boundary layer and mixing enhancement mechanism of the mixing layer has been obtained through this research.Artificial boundary-layer transition technique based on subharmonic resonance has been proposed and applied to the flow control in a scramjet inlet,inhibiting the flow separation of the boundary layer while improving the inlet performance.To guarantee the mixing of kerosene and supersonic airflow in the scramjet combustor,the mixing enhancement method based on subharmonic resonance has been adopted and a concept of combustor with smooth wall and low internal drag has been proposed for ignition and stable combustion.Finally,future turbulence research and technological development of aerospace vehicles is predicted.

Green perovskite light-emitting diodes with simultaneous high luminance and quantum efficiency through charge injection engineering

Metal halide perovskite light emitting diodes(PeLEDs)have recently experienced rapid development due to the tunable emission wavelengths,narrow emission linewidth and low material cost.To achieve stateof-the-art performance,the high photoluminescence quantum yield(PLQY)of the active emission layer,the balanced charge injection,and the optimized optical extraction should be considered simultaneously.Multiple chemical passivation strategies have been provided as controllable and efficient methods to improve the PLQY of the perovskite layer.However,high luminance under large injection current and high external quantum efficiency(EQE)can hardly be achieved due to Auger recombination at high carrier density.Here,we decreased the electron injection barrier by tuning the Fermi-level of the perovskite,leading to a reduced turn on voltage.Through molecular doping of the hole injection material,a more balanced hole injection was achieved.At last,a device with modified charge injection realizes high luminance and quantum efficiency simultaneously.The best device exhibits luminance of 55,000 cd m^-2 EQE of 8.02%at the working voltage of 2.65 V,current density of 115 mA cm^-2,and shows EQE T50 stability around 160 min at 100 mA cm^-2 injection current density.

An air-stable inverted photovoltaic device using ZnO as the electron selective layer and MoO_3 as the blocking layer

An air-stable photovoltaic device based on znic oxide nanoparticles （ZNP） in an inverted structure of indium tin oxide （ITO）/ZnO/poly （3-hexylthiophene） （P3HT）： [6,6]-phenyl C61-butyric acid methyl ester （PCBM）/MoO3/Ag is studied. We fm.d that the optimum thickness of the MoO3 layer is 2 nm. When the MoO3 blocking layer is introduced, the fill factor of the devices is increased from 29% to 40%, the power conversion efficiency is directly promoted from 0.35% to 1.27%.The stability under ambient conditions of this inverted structure device much is better due to the improved stability at the polymer/Ag interface. The enhancement is attributed to the high carriers mobility and suitable band gap of MoO3 layer.

Large scale current systems developed from substorm onset:Global MHD results

We investigate the large-scale substorm current systems developed from its onset in an idealized substorm event simulated by global magnetohydrodynamic(MHD) models. Mainly three current systems(loops) are revealed:(1) the classical substorm current wedge, which is composed by the disputed cross-tail current in the magnetotail, the nightside westward electrojet in the high-latitude ionosphere and a pair of region 1 field-aligned currents(FAC);(2) the partial-ring current system, which is braced by two region 2 FACs; and(3) the meridional current system, which is formed by an equatorial radial current(outward/inward in the morning/evening sector), and region 1 and region 2 FACs at its two ends. The region 2 FAC connects with region 1 FAC by a latitudinal horizontal current at each morning/evening ionosphere to complete Loops 2 and 3. A quantitative study shows the significant enhancement of these current systems during the substorm expansion phase, while Loop 1 dominates, which can reach a magnitude of ~1 MA. Empirical relations among the ionospheric currents and the related magnetotail currents are established based on the simulation results, implying that the substonn current systems are not evolved locally or separately, but must be viewed from a global perspective. This knowledge of large-scale substorm current system would deepen our understanding of the substorm development and could be validated by observations in the future.