Light weight replacement and the optimization design of bumper beam based on crash safety

Bumper beam is one of the key structural parts, which plays an important role in the frontal crashes of automobile. With the global trend of light-weighted automotive parts, the light weight of bumper beam attracts extensive attention of automobile manufacturers, and hot stamping technology with significant weight advantage has become one of the main light weight measures for bumper beam. The quasi-static press, low speed crash and frontal crash simulation models of bumper beam were established according to its actual working con- ditions in the automobile crashes. The feasibility of replacing normal steel bumper beam with hot stamping bumper beam was analyzed. Meanwhile, the stiffeners in the front face of hot stamping bumper beam were optimized with topography optimization in order to further improve its performances.     

Blasting technologies of vibration damping in subway tunnel passing under upper buildings closely

Reducing the blasting vibration is important for blasting excavation in subway tunnel construction. Taking the 3rd bid section of Line 3 of Qingdao subway project as an example, the distance between tunnel vault and ground is 5 - 8 m. In order to insure the safety of the upper buildings, technologies of parallel cut with large diameter empty hole, one-time initiation and delay by parts, and multiple shallow holes were adop- ted in the project. The results showed that the maximum value of vertical vibration was limited in the criterion allowance, and the upper buildings were not damaged. Besides, problems were solved that the number of nonel detonator was difficult to meet the requirements of excavating a large cross-section tunnel by blasting, multiple cross-section could＇ t be initiated simultaneously, and construction efficiency was low, which ensure the con- struction safety and schedule.     

Development and application research of light weight heat treated B-grade bulletproof steel

The light weight heat treated B-grade bulletproof steel was developed through composition design and optimization based on multiplex alloying, multiplex micro-alloying design ideas and complex phase structure strengthening theory. The puzzle how to avoid the quenching deformation problem of super high strength thin sheet was solved through heat treatment in a die with a set of cooling system. Such B-grade bulletproof steel plate has fine tempered lath martensite structure. The shooting and certification test results showed that the shoot resistance of B- grade bulletproof steel plate can meet the protection demand of Protection specification for cash carrying vehicles （GA 164--2005）. In comparison with B-grade bulletproof steel plate made by one of the companies in Sweden, the weight of the developed B-grade bulletproof steel plate can be decreased by 8 % under the same shoot resistance condition. It will be meaningful for cash truck and anti-hijacking vehicle to realize light weight, energy conservation and emission reduction.     

A 65-nm 1-Gb NOR floating-gate flash memory with less than 50-ns access time

This paper presents a 65-nm 1-Gb NOR-type floating-gate flash memory, in which the cell device and chip circuit are developed and optimized. In order to solve the speed problem of giga-level NOR flash in the deep submicron process, the models of long bit-line and word-line are first given, by which the capacitive and resistive loads could be estimated. Based on that, the read path and key modules are optimized to enhance the chip access property and reliability. With the measurement results, the flash memory cell presents good endurance and retention properties, and the macro is operated with 1-las/byte program speed and less than 50-ns read time under 3.3 V supply.     

Optimization of Culture Components for Laccase Activity from Pleurotus Ostreatus P40 Using Response Surface Methodology

High enzymatic activity is required for laccase applications.Central composite design （CCD）-based response surface methodology （RSM） can effectively increase the enzymatic activity of Pleurotus ostreatus P40 in liquid substrate fermentation.Initial screening of the nutritional components was performed using a Plackett-Burman design.The variables,namely,bran,bagasse,Tween 80,and yeast extract,were found to have statistically significant effects on laccase activity.These variables were further optimized using CCD-based RSM.Optimal concentrations for the maximum laccase activity were 8.144 2 g/L bran,50 g/L bagasse,0.424 1 mL/L Tween 80,and 2.832 5 g/L yeast extract.Under optimized conditions,the maximum measured laccase activity reached 96 480 U/L,which was close to the predicted value （104 830 U/L） by RSM.Therefore,RSM can be used to optimize culture components for laccase activity from Pieurotus ostreatus P40.     

Four basic laws in design science

A point on the distinction between design and science is given and the connotanons of aeslgn science are discussed in the paper. Design should be understood as the first step of all human＇ s purposeful activity, which is a daily behavior for everyone. Four laws are summarized, which describe the basic patterns of design and are the constituents of design science. They are the law of design based on existed knowledge, law of in- completeness of design knowledge, law of design centered on new knowledge acquirement and law of competi- tiveness of design knowledge. The four basic laws show the knowledge essence of design. To enrich the existed knowledge, to make it convenient to be used, to teach designers with high intuition and inspiration in picking useful elements of existed knowledge and shaping competitive ideas and to have strong new knowledge acquire- ment facility are the basic conditions of good designs. Study of design science will promote the structure of tra- ditional engineering education. An important conclusion is derived that there will be no successful innovation without good design.     

Integrated extremum seeking control method and its application to the suppression of combustion instabilities

The suppression of combustion instabilities using the extremum seeking algorithm （ESA） is analyzed. A function model of the pressure oscillation and the mean fuel-air ratio in the combustion chamber is derived and implies an extremum relation between the oscillation amplitude of the pressure and the mean fuel-air ratio. Hence, the control system of combustion instabilities can be considered as an extremum seeking control system （ESCS）. All traditional ESCSs employ a separate design method, which divides the design of the ESA from the controller design. It is thus difficult for traditional ESCSs to achieve optimal performance of the control system. To solve this problem, an integrated extremum seeking control method for ESCSs is proposed. Using this integrated control, the minimal oscillation amplitude of the pressure is realized by adaptively seeking the optimal mean fuel-air ratio. Hence, this design method can effectively suppress combustion instabilities in aeroengines. By comparing simulation results, the effectiveness of the proposed method is validated.     

Anomalous top-quark coupling effects in rare B and K decays

The Large Hadron Collider at CERN is performing direct searches for top-quark anomalous flavor-changing neutral current （FCNC） processes. However, these processes may be correlated closely with the low-energy rare B and K meson decays. In this paper, we review the anomalous top-quark coupling effects in these low-energy flavor transitions, summarize the flavor constraints and discuss their implications for direct detection of top-FCNC processes at the Large Hadron Collider.     

Fabrication and Properties of Microencapsulated n-octadecane and Paraffin

Microencapsulated n-alkanes as energy- storage materials have promising application prospects. The ndcrocapsules containing 100 - 50 wt% of n - octadecane, 0 -20 wt% of paraffin and 0 - 30 wt% of cyclohexane were synthesized by in-situ polymerization using melamine- formaldehyde polymer as shell. Cyclohexane was removed after heat-treated the microcapsules at 100℃. The morphologies, cell parameters, phase change properties, thermal stable temperatures of these microcapsules were examined. The diameters of these microcapsules are lower than 5 μm. The effect of paraffin in the microcapsules on the cell parameters of n-octadecane is negligible. The paraff＇m is effectively used as a nucleating agent to decrease the degree of supercooling. The melting enthalpy is decreased from 132 J/g to 111 J/g due to the increase of the cyclohexane contents. The thermal stable temperature is enhanced 6 - 16℃ after heat-treated the microcapsules at 160℃ for 30 min.     

An observational study of snow aging and the seasonal variation of snow albedo by using data from Col de Porte,France

An 18-year long （1993-2011） comprehensive dataset of snow and meteorological variables from Col de Porte, France is used to analyze the variation of shortwave broadband albedo with elapsed time after snowfalls （snow aging） during each snow season. The effects of air temperature, snow surface temperature and snow depth on snow albedo are investigated. An index based on the accumulation of air temperature over several consecutive days with daily mean higher than 2.5 ℃ is proposed to divide each snow-covered period into a dry and the following wet snow season when this index reaches 18 ℃. The results indicate that snow surface albedo decreases exponentially with time in both dry and wet snow seasons. Snow albedo reduction with snow aging is small at low surface temperature and the reduction rate increases with the rise of surface temperature. However, the reduction rate is widely scattered within the observed range of temperature, implying a loose relationship between snow albedo and snow surface temperature. Snow albedo in wet snow season is generally smaller and decreases faster than in dry snow season. For Col de Porte site, snow depths to effectively mask the underlying surface are 21 and 33 cm in dry and wet snow season respectively.     

Research and Practice of Dynamic Network Security Architecture for IaaS Platforms

Network security requirements based on virtual network technologies in IaaS platforms and corresponding solutions were reviewed.A dynamic network security architecture was proposed,which was built on the technologies of software defined networking,Virtual Machine(VM)traffic redirection,network policy unified management,software defined isolation networks,vulnerability scanning,and software updates.The proposed architecture was able to obtain the capacity for detection and access control for VM traffic by redirecting it to configurable security appliances,and ensured the effectiveness of network policies in the total life cycle of the VM by configuring the policies to the right place at the appropriate time,according to the impacts of VM state transitions.The virtual isolation domains for tenants’VMs could be built flexibly based on VLAN policies or Netfilter/Iptables firewall appliances,and vulnerability scanning as a service and software update as a service were both provided as security supports.Through cooperation with IDS appliances and automatic alarm mechanisms,the proposed architecture could dynamically mitigate a wide range of network-based attacks.The experimental results demonstrate the effectiveness of the proposed architecture.     

Distribution and origin of high magnetic anomalies at Luobusa Ophiolite in Southern Tibet

The Luobusa Ophiolite,Southern Tibet,lies in the eastern portion of Indus–Yarlung Zangbo suture zone that separates Eurasia from the Indian continent.An aeromagnetic reconnaissance survey has revealed an EWtrending Yarlung Zangbo River aeromagnetic anomaly zone,and it is considered to be caused mainly by the Indus–Yarlung Zangbo Ophiolite.The Luobusa Ophiolite reflects the eastern portion of the Yarlung Zangbo River aeromagnetic anomaly zone.Conventionally,the ultramafic rock in the Luobusa Ophiolite is considered as the origin of the high magnetic anomalies.However,results from the surface magnetic survey and the magnetic susceptibility measurements from drill cores indicate that the high magnetic anomalies are distributed inhomogeneously in the Luobusa Ophiolite.In some cases,the susceptibility exhibits more than 30 times difference between two sides of the same sample.A fact emerged that the susceptibility of dunite with serpentinization is higher than that of fresh dunite,harzburgite and chromite when we analyzed the measurement results.In order to understand the origin of the high magnetic anomalies,we measured the density and susceptibility of 17 samples,microscopic and electron probe analyses have been performed as well.The result indicates the presence of dunite with serpentinization containing an abundant of micro-fissures filled with magnetite.Olivine has a susceptibility of about 2.7–351(910-5SI),pyroxene about 16–320,and chromite about200–800.All these units feature relatively low susceptibility in ultramafic rock,and only the magnetite is characterized by a high susceptibility of about 200,000(910-5SI).Based on these observations,we conclude that the precipitation of magnetite in the process of serpentinization of the olivine caused by the geological process in the Luobusa Ophiolite is the origin of high magnetic anomalies.     

Effect of strain rate on the compressive deformation behaviors of lotus-type porous copper

Lotus-type porous copper was fabricated by unidirectional solidification, and compressive experiments were subsequently conducted in the strain rate range of 10-3–2400 s-1 with the compressive direction parallel to the pores. A GLEEBLE-1500 thermal-mechanical simulation system and a split Hopkinson pressure bar (SHPB) were used to investigate the effect of strain rate on the compressive deformation behaviors of lotus-type porous copper. The influence mechanism of strain rate was also analyzed by the strain-controlling method and by high-speed photography. The results indicated that the stress-strain curves of lotus-typed porous copper consist of a linear elastic stage, a plateau stage, and a densification stage at various strain rates. At low strain rate (< 1.0 s-1), the strain rate had little influence on the stress-strain curves; but when the strain rate exceeded 1.0 s-1, it was observed to strongly affect the plateau stage, showing obvious strain-rate-hardening characteristics. Strain rate also influenced the densification initial strain. The densification initial strain at high strain rate was less than that at low strain rate. No visible inhomogeneous deformation caused by shockwaves was observed in lotus-type porous copper during high-strain-rate deformation. However, at high strain rate, the bending deformation characteristics of the pore walls obviously differed from those at low strain rate, which was the main mechanism by which the plateau stress exhibited strain-rate sensitivity when the strain rate exceeded a certain value and exhibited less densification initial strain at high strain rate.     

Observations of thermospheric vector wind over Yellow River Station during auroral substorm events

Strong disturbances associated with auroral substorms originate from the ionosphere-magnetosphere owing to the effects of the solar wind, and the wind field in the ionosphere is related to such substorm activity. Here, we describe the analysis of four auroral substorm events, for which we employed an all-sky Fabry-Perot interferometer to observe the two-dimensional horizontal wind field and combined the results with data from an all-sky charge-coupled device imager, a fluxgate magnetometer installed at Yellow River Station, and the Super Dual Auroral Radar Network. The results demonstrate that, during auroral substorms, the vector wind field is related closely to variations in the ion drift and geomagnetic field. Moreover, we observed a changing wind field of approximately 300 rn/s in response to variations in the electric and magnetic fields （likely caused by ion drag） and a disturbance of about 200 m/s that we attribute to the interaction of Joule heating and ion drag.     

Measurement and characteristics of ground vibration caused by blasting demolition of urban overpass

To analyze the characteristics of ground vibration caused by blasting demolition of urban overpass, in this paper we introduced the measurement method and then studied the characteristics of recorded ground vi- brations. Through the analysis of peak acceleration, peak frequency and duration, results indicated that the ver- tical component of vibration is the most important in the region close to the collapse point; the collapse of bridge segments will lead to superposition of ground vibration, and isolation measures can reduce the peak ac- celeration but increase the duration of vibration; blasting and collapse vibration cause no damage to the re- served structure which indicates that blastin~ demolition is a safe and effective method.     

Safety analysis and control of blasting mining area adjacent to infrastructure

Systematic analysis of influence of blasting vibration on bridges, tunnels, slopes and the mechanical relationships between each other were drawn based on the example of safety argument between blasting mining area and protected objects. The safety argument methods and technological means of controlling dangerous and harmful factors were proposed by the application of principle of risk analysis. And standard control system was established based on controlling the blasting parameters of division of blasting area.     

4 K high frequency pulse tube cryocooler used for terahertz space application

Terahertz(THz) frequency region, defined from0.1 to 10 THz, is an important frequency band for radio astronomy and atmospheric science. As NbN Superconductor-Insulator-Superconductor(SIS) mixers used for terahertz detection, which are studied by the Purple Mountain Observatory(PMO), Chinese Academy of Sciences(CAS), work at 8–10 K, and require condition of micro vibrations, its astronomical observation in aerospace is limited by suitable refrigeration method. 4 K high frequency pulse tube cryocooler developed by Key Laboratory of Space Energy Conversion Technologies(SECT), Technical Institute of Physics and Chemistry(TIPC), CAS, offers an opportunity for the application of SIS mixers. This article introduces the progress of the two-stage high frequency pulse tube cryocooler researched by TIPC. The cryocooler has reached a no load temperature of 4.5 K which is the lowest temperature for this kind of cryocooler reported so far. The successful coupling between the THz component and the high frequency pulse tube cryocooler lays a solid foundation for space detection in the terahertz band.     

Kinetics of blue-green light-induced state transition and fluorescence quenching in the wild-type cyanobacterium Synechocystis PCC 6803 and apcD − and apcF − mutants

State transition and blue-green light-induced fluorescence quenching are two short-term processes in cyanobacteria. The details of their kinetics and the relationship between these processes have not been elucidated. In this work, these two processes were studied in the wildtype cyanobacterium Synechocystis PCC 6803 cells as well as in apcD^- and apcF^- mutants by monitoring their time- dependent 77 K fluorescence responses to blue-green light （430-540 nm） at a series of intensities ranging from 20-800 μE m^-2 s^-1. The lowest light intensity to induce fluorescence quenching in wild-type cells was 160 μE m^-2 s^-1 under the selected experimental conditions, while state transition took place at the intensities lower than 160 μE m^-2 s^-1 at a conservative level, but at variable rates. The quenching level increased at intensities higher than 160 μE m^-2 s^-1, reaching the maximum level at intensities equal to or higher than 200 μEm^-2 s^-1. Fluorescence kinetics indicated that both the length of the induction period and time required to reach the maximum level were functions of light intensity. State transitions as well as fluorescence quenching took place in both wildtype and mutant cells, but might involve different mechanisms.     

Key technologies of precision demolition blasting of ultra-long urban viaduct in complicated surroundings

The key technologies of precision blasting were put forward based on the characteristics of urban via- duct blasting demolition in complicated surroundings. Initial bending instability mechanics model of reinforcing steel bar frame of blasting fragmented pier and sequenced collapsed dynamic model were established for quanti- tative blasting design. Technologies of water pressure blasting were applied in multi-cell box girder fragmenta- tion. The detonating network of non-electric duplication crossover was adopted for the safety and reliability of ultra-long delay. The rationality of blasting scheme and parameters were validated by physical model test. Harm- ful effects were forecasted and controlled by integrated protective technologies. Specialization, cooperation, pre- cision, execution （SCPE） project management method was put forward for precision management. The key tech- nologies of precision demolition blasting can provide reference for similar proiects.     

Equilibrium between titanium ions and high-purity titanium electrorefining in a NaCl-KCl melt

TiCl_x (x = 2.17) was prepared by using titanium sponge to reduce the concentration of TiCl₄ in a NaCl-KCl melt under negative pressure. The as-prepared NaCl-KCl-TiCl_x melt was employed as the electrolyte, and two parallel crude titanium plates and one high-purity titanium plate were used as the anode and cathode, respectively. A series of electrochemical tests were performed to investigate the influence of electrolytic parameters on the current efficiency and quality of cathodic products. The results indicated that the quality of cathodic products was related to the current efficiency, which is significantly dependent on the current density and the initial concentration of titanium ions. The significance of this study is the attainment of high-purity titanium with a low oxygen content of 30×10-6.