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Dynamic compressive behavior of 2 kinds of Al/Teflon reactive materials samples are analyzed by using the Split Hopkinson pressure bar. The mass percentage of the samples is 26.5% Al and 73.5% Tefl...

Turbulence modulations by particles of a swirling gas–particle two-phase flow in an axisymmetric chamber are numerically simulated. To fully consider the preferential concentrations and the anisotropic dispersions of particles, a second-order moment model coupling particle–particle collision model was improved. Experimental validation for the proposed model, algorithm, and in-house codes by acceptable match was carried out. The effects of ultralight-expanded graphite and heavy copper particles with a large span of Stokes number on gas velocities and fluctuations, Reynolds shear stresses and tensor invariants, turbulence kinetic energies, and vortice structures are investigated. The results show that turbulent modulation exhibits strong anisotropic characteristics and remains in a close relationship with the flow structure. Modulation disturbances and vortex evolution are enforced by heavy-large particles with higher Stokes numbers. Preferential accumulations of ultralight particles in shear stress regions at lower vortices are weaker than those of heavy particles. For axial turbulence modulations, a heavy particle plays the primary role in the inhibition action because of larger inertia, and a light particle contributes to the enhancement effect due to excellent followability. The instantaneous flow information and coherent turbulent structure are failed to be acquired due to the limitation of the Reynolds time-averaged algorithm.

Aluminum honeycomb framework reinforced Al/PTFE material is a kind of high inert energetic material, which has higher strength and structure advantages than that of pure Al/PTFE material. In order to meet the requirements of special penetration/blasting performance, this paper adds aluminum honeycomb framework with arm length of 1.5 mm into the traditional formula Al/PTFE (mass percentage of Al and PTFE is 26.5% and 73.5%). The energetic material reinforced by aluminum honeycomb framework (20.5% Al/73.5% PTFE/6% aluminum honeycomb) is obtained by cold pressing sintering，and the experimental evaluation of release energy generated by high velocity impact in vacuum was performed by using two-stage light gas gun loading system, transient optical fiber pyrometer measurement system, overpressure measurement system and infrared thermal imager measurement system. Experimental results show that the impact reaction temperature is about 700 °C in vacuum in the velocity range of 0.96–1.5 km/s, and the energy release of the specimen increases with the increase of impact velocity. When the impact velocity is greater than 1.5 km/s, the specimen fully reacts, and the energy released by the complete reaction of the specimen does not exceed 8.3 kJ/g.

Erianin is a natural small molecule dibenzyl compound extracted from Dendrobium officinale or Dendrobium chrysotoxum. Studies show erianin has many pharmacological functions such as antioxidant, antibacterial, antiviral, improving diabetic nephropathy, relaxing bronchial smooth muscle and anti-tumor. However, the erianin-mediated molecular mechanism is elusive, and the target protein of erianin is not clear yet. Here, we screened and identified that the target protein of erianin in human hepatoma HepG2 cells is human pyruvate carboxylase, and explored the anti-tumor signal pathway regulated by erianin in several cell lines. Firstly, the interaction between human pyruvate carboxylase and erianin was studied by bioinformatics and biochemical methods. Secondly, in vitro, erianin can specifically inhibit the activity of human pyruvate carboxylase, and the purified human pyruvate carboxylase can specifically bind to the activity probe of erianin. Thirdly, human pyruvate carboxylase is highly expressed in a variety of malignant tumors, and the inhibitory effect of erianin on tumor cells is positively correlated with the expression of human pyruvate carboxylase, and erianin can selectively inhibit the activity of pyruvate carboxylase. Finally, erianin can regulate the pyruvate carboxylase-mediated Wnt/ β- Catenin pathway. All of which provide important data for the further study of the anticancer mechanism of erianin, and lay a solid foundation for the further development and utilization of erianin.

Landfill is the major waste disposal method of high-moisture coal gasification fine slag (GFS) which causes the pollution of soil and water and brings the waste of resources. GFS efficient dewatering is an urgent problem to be solved, which is beneficial to realize its resource utilization. In this paper, mechanical pressure and vacuum coupling energy fields are applied to carry out the dewatering processes of GFS. The pressure field provides strong power for water migration, which makes water leave the particle system, while the vacuum field provides traction for water removal from system. The fine slag produced from Coal-to-methanol (named JC) with larger size particles tends to form "bridging" frameworks among particles, which provides water occurrence space and increases the moisture migration resistance. The mechanical dewatering process has an energy advantage interval, when the sample moisture is reduced to a certain degree, the mechanical force field is mainly used for particle friction and breakage but not for moisture migration. Through dewatering process energy optimization, high moisture gasification fine slag can be removed about 15% water within 30s and energy consumption of efficient dewatering is 2.63 kJ/g which is much lower than that of drying. Efficient dewatering is benefit to the GFS recycling which reduces hazardous materials release to environment. The potential effects of high efficiency dewatering process on GFS resource utilization and the possible eco-design framework for products recycled from the waste GFS were proposed. The research results will provide theoretical guidance for the gasification fine slag efficient dewatering and is benefit to the environment.

This paper investigates the sputtering distribution of LIPS200 ion thruster plume. Considering the ground test results cannot fully represent the on-orbit status, computer simulation is highly needed to study the sputtering distribution on orbit. To ensure the credibility of simulation results, the experimental and simulation analysis in the ground test conditions were performed. After verification of the experimental results, we carried out the simulation analysis in on-orbit condition (vacuum condition). The results show that, within the off-axis angle of 70° (deg), the sputtering distribution in the ground test condition is basically the same as that in vacuum condition, and the main particles causing sputtering are Xe+ and Xe2+. In the region of the off-axis angle greater than 70 deg, the sputtering result in vacuum condition is obviously lower than that in the ground test condition, and the sputtering effect is mainly caused by the charge-exchange (CEX) ions. The CEX ions in the ground test condition and vacuum condition show the “jet like” and the “mushroom like” distributions respectively. This work verifies the feasibility of the hybrid Particle-in-Cell and Direct Simulation Monte Carlo (PIC DSMC) simulation method as well as the sputtering model to predict the space sputtering effect which can be introduced as a reference for the design of electric propulsion spacecraft.

Accurate measurement of heat flux (HF) is significant in both industrial engineering and scientific research. It is acknowledged that the radiative HF can be easily determined by radiometers. In order to measure the conductive or convective HF distribution flowing across a surface, this paper presents a novel non-contact measuring method based on the infrared (IR) technique and inverse heat transfer method (IHTM). In addition, a specially designed multi-color-reference (MCR) which is composed of four sectors with four different known emissivity will be attached to the focused surface in the practical measurement. Therefore, different radiation signals among the four different sectors of MCR as well as the focused surface will be detected by an IR camera, through which a whole radiation temperature map can be obtained. Based on the differences in the radiation temperatures of the surface and MCR, the IHTM can be adopted to yield useful boundary conditions such as emissivity of the surface, convective heat transfer coefficient, and the critical HF distribution. The measuring method presented in this study combines the advantages of contact and non-contact measurement, which can accurately obtain the HF distribution under the difficult-contacted conditions such as the HF monitoring of a boiling furnace, HF estimating of the aerodynamic heating surface, etc. Numerical simulation and experimental verification were organized to justify the newly-developed measuring method. Relative error in the simulation is estimated to be less than 2%, and that in the experiment is calculated to be around 4.23%. The result displays a relatively high precision of the measuring method, demonstrating that such a method can be applied in practical application.

The International Space Station continues to be a productive space research laboratory after decades of operations, and it has proven to be a variable resource for observing spacecraft floating pot...

Young’s modulus and friction force of the gecko-inspired materials are important parameters for the applications of climbing robots and devices. Increasing the friction force of polymer composite pillar with desirable Young’s modulus is current research focus to expand the potential applications of bio-inspired materials. Also, the stability of inspired pillar under radiated exposure is essential to be investigated to explore the irradiation effect on patterned composite array. Here the boron nitride nanosheets (BNNSs) have been exfoliated with assistance of hyperbranched polyethylene (HBPE) as polymer stabilizer via CH-π non-covalent interaction. The nanosheets were incorporated into polydimethylsiloxane (PDMS) mixture that was then utilized to prepare composite pillar via plasma etched silicon template. The electron irradiation was conducted to examine the morphology of patterned array and the mechanical property of PDMS composite. The coefficient of friction for PMDS composite decreases slightly after irradiation, and it retains high value around 1.2 for 0.2 wt% composite pillar with comparison to 1.3 for PDMS. The stress for irradiated PDMS decreases from 3.1 MPa to 1.8 MPa with the strain of 281% at accumulating dose of 5 × 1015 rad. During irradiation, the doubling terminating reaction is probably induced by the active radical sites in elastomer. The PDMS pillar exhibits large friction coefficient and high mechanical property due to new crosslinking network of elastomer during irradiation. This work develops polymer composite with pillar architecture by silicon template method, and sheds a light on the electron irradiation effect of composite pillar to pave the path for the application of gecko-inspired material in spacecraft.

Melanoma is the most malignant and aggressive form of skin carcinoma originating in the pigment-producing melanocytes. In this study, to further investigate the molecular mechanisms of the development and progression of melanoma, we explored the impacts of long non-coding RNA (lncRNA) CASC2 on melanoma cell functions. Microarray analysis was carried out to identify the expression of lncRNA CASC2 in melanoma cells. MiR-181a was predicted as a sponging target of CASC2 by miRcode, while the 3'-UTR of Plexin C1 (PLXNC1) was a potential target of miR-181a according to the TargetScan database. The correlation among CASC2, miR-181a, and PLXNC1 was verified by dual luciferase reporter assay and qRT-PCR. After manipulation of CASC2, miR-181a and PLXNC1 expression with transfection in A375 and M14 cells, cell viability, apoptosis, and invasive ability were evaluated using CCK-8, flow cytometry and Transwell assays, respectively. A low expression of CASC2 was detected in melanoma tissues and cells. Dual luciferase reporting assay confirmed that miR-181a targeted the 3'-UTR of PLXNC1. Furthermore, CASC2 could efficiently sponge miR-181a, thereby facilitating the expression of PLXNC1. Up-regulation of CASC2 suppressed the cell proliferation and invasion, but induced the apoptosis of melanoma cells. Our results demonstrated that lncRNA CASC2 can promote PLXNC1 expression by sponging miR-181a, thereby inhibiting the proliferation and invasion of melanoma cells, indicating that lncRNA CASC2 functions via the miR-181a/PLXNC1 axis in melanoma.

Discharge monitor is a kind of primary payload monitor loaded on the manned spacecraft in the Low Earth Orbit, which is designed for monitoring the secondary discharge problem on the solar array. The issue of integrated electronic device heat dissipation is the key for normal operation supporting. In this study, the integral payload is simulated by finite element method, through structure modeling, based on the theory of heat conduction and heat radiation. In the result, under the measures of adjusting the layout of the electronic devices, coating the circuit board with copper, and black anodization for the case, the payload could definitely meet the needs of the heat dissipation in the extreme conditions, survive safely and functionalize perfectly in the orbit, at least from the angle of thermal design.

Geosynchronous spacecrafts are likely to be charged to several or even tens of thousands of kilovolts due to the high energy plasma during sub-storms (tens of keV), leading to detrimental electronic system anomalies. Recently, a debate on what is the best index for geosynchronous spacecraft charging is opened. Ferguson, D. C. et al. [Ferguson and Wimberly, 2013; Ferguson, et al., 2015] presented that the total thermal electron flux above a certain minimum energy that is well above the second crossover point in secondary electron emission is the best index for spacecraft charging, and verified the charging index by comparing Nascap-2k results with charging and flux measurements on some geosynchronous satellites. In this paper, such a charging index is verified theoretically. Meanwhile, the best minimum energy and the electron flux above it are obtained both for single and double Maxwellian plasma based on charging threshold theory. The theoretical estimations agree well with Ferguson's results. Such a charging index is important, which will probably make prediction of geosynchronous spacecraft charging simple and convenient in the future.

Geosynchronous spacecraft charging has been a focus of attention since a large number of satellites are operating in this region. The most severe geosynchronous charging environment is during substorms, in which the plasma environment is generally better described by double Maxwellian distribution. In such case, determination of onset of spacecraft charging becomes more complex since more parameters are involved. In this paper, the threshold condition for onset of charging in double Maxwellian plasma is developed theoretically in a more general sense, and the charging behavior at the threshold is investigated in detail. It is found that sudden jump to negative potential of thousands of volts or more can take place at the threshold in certain situation. The mechanism underlying the potential jump is clarified from the stability theory and illustrated by typical calculations. Moreover, a more general condition for potential jump is determined theoretically, and consequently another threshold condition for jump in positive direction is found. At both thresholds, the spacecraft potentials are semisteady, but in opposite directions, with the possibility of a jump to a stable potential. The polarity of movement across the thresholds from different plasma will cause a spacecraft to experience irreversible charging histories which result in significant hysteresis.

Gamma imager capable of monitoring, detection and localization of radioactive sources is of critical importance for nuclear safety and homeland security with the increasing use of radioactive sources in applications of nuclear technology. A 4π view gamma imager based on gamma ray occlusion technique is under development in our lab. The key component of the gamma imager is a 3D position-sensitive detector, which enables 4π field of view of the imager. In this work, we propose a 3D positionsensitive detector design for the 4π view gamma imager based on dual-ended readout (DER) technique. The detector was composed of a GAGG block coupled to an SiPM array at both crystal ends. DOI calibration was conducted with a collimated fan beam 18F source and DOI resolution was evaluated. Energy calibration was performed for each 3D position region of the detector by incorporating 3D position information to correct for the energy response inconsistency at different 3D position regions inside the detector. Various radioisotopes including 99mTc, 131I, 137Cs and 22Na were tested. An exponential factor was applied to compensate for energy response non-linearity due to SiPM saturation effect at higher gamma energy. The measured average DOI resolution was 1.96 ± 0.21 mm for all the four DER detector modules, indicating excellent 3D positioning accuracy of the detector design. With the proposed energy calibration approach, characteristic photopeaks of each radioisotope can be clearly identified at the correct energy position on the measured energy spectra. The achieved energy resolution was 9.76% at 662 keV, demonstrating good energy performance of the detector design, which could benefit radioisotope identification capability of the gamma imager. To conclude, the proposed 3D position-sensitive detector design based on DER technique features good 3D positioning and energy performance and is feasible for the 4π view gamma imager.

In this paper, we investigate the effect of thermal annealing on the degree of crystallinity, the fraction of electro-active phase (β-phase) and the dielectric properties, such as dielectric constant and loss tangent. Through control the thermal annealing conditions, dramatic improvements have been achieved. The degree of crystallinity is greatly enhanced up to 45.2%. The relative content of electro-active phase increases remarkably by 61% and the dielectric constant is improved greatly by 17.8% and reaches its maximum value of 9.9 meanwhile the dielectric loss being as low as 0.026.

For disturbed geosynchronous plasma, the onset of spacecraft charging and its evolution become more complex than quiet environment. A sudden jump of spacecraft potential can occur in specific environment conditions which can be detrimental to onboard electronics. In this paper, the potential jump for geosynchronous spacecraft charging is theoretically modeled and comprehensively characterized. Two types of potential jump in opposite directions are elucidated and the threshold conditions for both types of jump are determined. At both thresholds, the spacecraft potentials are semi-steady, but in opposite directions, with the possibility of a jump to a stable potential. The polarity of movement across the thresholds from different plasma will cause a spacecraft to experience irreversible charging histories which result in significant hysteresis. Generally, the jump to negative potential occurs with greater magnitude as compared to a potential jump in positive direction. Ion distribution has negligible influence to the threshold condition for jump to negative potential. However, ion distribution significantly affects the threshold for jump to positive potential and subsequently modifies the parametric domains of spacecraft charging.

Flexible electrodes have been extensively investigated to fulfill the development of highly advanced human interaction electronics. It's still a challenge to develop the conductive film for the scalable device with low resistance under large deformation. In this work, we reported a stretchable conductive layer on elastomer substrates assembled by few-layer graphene, which was exfoliated in the low-boiling organic solvent with assistance of hyperbranched copolymer as stabilizer that was adsorbed on the nanosheets via CH-π non-covalent connections. The relative resistance change of graphene film is 117% as the mechanical strain reaches 35%, which retains high conductivity under tensile operation. The resistance of the graphene electrode is dependent on the overlapping of the nanosheets during the deformation, in which the slipping of nanosheets is due to the lubricant effect of the hyperbranched segments acting as dynamic CH-π interactions. This work highlights a general strategy of the stretchable conductive film for the flexible electronics, and sheds a light on the conduction mechanism for the graphene film during large deformation.

The data detected by the cosmic-ray imaging detector used to imaging the distribution of nuclear fuel cannot be transmitted outside the vessel. An ultrasonic through-wall communication system is designed to support the true-wireless monitoring in NPPs. This system could transmit data through the Steel Lining or the concrete wall of the containment wirelessly without cables and penetration, which could protect the leakproofness and integrity of the containment and enhance the safety of NPPs. With 40 kHz ultrasonic carrier waves, this system could communicate at 4.8kbits/s baud rate through over 10cm concrete wall, over 10cm steel liner and 10cm lead + 5cm steel combination wall. An application test has been finished on the 20:1 experiment containment to AP1000 in the Beijing Key Laboratory of Passive Safety Technology for Nuclear Energy, this system could operate steadily with 0 error rate.

Charging of geosynchronous satellites has been attracting much attention. The geosynchronous plasma is generally modeled by single-Maxwellian distribution or better modeled by double-Maxwellian distribution in disturbed environments. For single-Maxwellian plasma, the critical temperature has been predicted theoretically for onset of negative surface charging. While for double-Maxwellian plasma, in which charging determination becomes more complicated, there is not an analogous threshold condition developed so far. In this paper, the threshold condition for onset of negative charging in eclipse is developed theoretically, namely, the spacecraft charging can be triggered when the weighted average of the total averaged yields of secondary and backscattered electron for the two plasmas equals to unity. The threshold condition indicates that both temperatures and density ratio of the two components are decisive to onset of spacecraft charging. The charging behaviors for two typical cases are discussed; it is found that sudden potential jump at the threshold does not always occur, which is different from conventional understandings. Whether the potential jumps abruptly or transits smoothly to negative domain depends on the specific condition. The criterion for potential jump with a short form is acquired theoretically, and it predicts the necessary condition that a sudden potential jump or continuous transition occurs.

Infection with the Ebola virus can cause severe acute hemorrhagic fever in humans and nonhuman primates. The virus is highly virulent and there are no effective drug treatments or vaccines available to date. The largest recorded outbreak of Ebola virus disease (EVD) is currently ongoing; it has affected West Africa, which is outside of its previously reported and predicted niche. It was declared a Public Health Emergency of International Concern by the World Health Organization. Here, we reviewed studies on EVD and its associated etiology, ecology, and epidemiology, spanning approximately 40 years. Multi-disciplinary theoretical knowledge was integrated to explain the reasoning behind Ebola virus persistence, circulation, and spread, including knowledge relating to natural reservoir hosts and a detailed description of the role of bats and other wildlife in the spread of the Ebola virus. To prevent the spread of major pathogens from wild animals to humans, it is crucial to put forward the most effective measures of maintaining the security of social public health. It is essential to strengthen wildlife disease surveillance, establish a long-term, comprehensive surveillance system for early warning and prevention methods, and provide a scientific basis for better safeguarding of public health and safety.

A novel method of producing flexible graphene-based paper (GBP) electrodes through the direct hydrothermal reduction of graphene oxide based paper is developed. On the basis of an electrostatic attraction mechanism or pH-enhanced π–π attraction mechanism, a delicate balance between integrity, flexibility and porosity of GBPs is maintained during the hydrothermal treatment process, providing them with excellent compositional, microstructural and supercapacitive characteristics. Furthermore, the insertion of CNT into the graphene interlayer spaces immensely improves the specific capacitance (up to 195 F g−1) and rate capability (10 A g−1) of the supercapacitors assembled with these GBPs. In addition, the facile and simple preparation procedures and arbitrarily controlled area and thickness of the GBPs predict their promising industrialization potential.

This work reports on the systematic comparison of the crystalline structural, morphological and hydrophobic properties of ZnO and Al-doped ZnO (AZO) thin films fabricated by atomic layer deposition and the hydrothermal method. It was revealed that the surface wettability can be largely modified by Al doping in the zinc oxide film growth process. With Al doping, the morphology of the AZO films became more complex and rough. The water contact angle of a flower-like hierarchical ZnO film (123 ± 4°) was improved by about 40° via Al doping to 160 ± 4°. We attributed the variation in surface hydrophobicity with Al doping to changes in the bond angle and distance between ZnO–H2O molecule. The computational simulations have been employed to verify the interfacial distinction between two main crystal orientations of AZO. This result suggests that Al doping can be considered a critical factor in changing the surface morphology of AZO as well as the hydrophobic properties. It is believed that the present route holds promise in the design and application of practical superhydrophobic materials.

Melanoma is the most malignant and aggressive form of skin carcinoma originating in the pigment-producing melanocytes. In this study, to further investigate the molecular mechanisms of the development and progression of melanoma, we explored the impacts of long non-coding RNA (lncRNA) CASC2 on melanoma cell functions. Microarray analysis was carried out to identify the expression of lncRNA CASC2 in melanoma cells. MiR-181a was predicted as a sponging target of CASC2 by miRcode, while the 3'-UTR of Plexin C1 (PLXNC1) was a potential target of miR-181a according to the TargetScan database. The correlation among CASC2, miR-181a, and PLXNC1 was verified by dual luciferase reporter assay and qRT-PCR. After manipulation of CASC2, miR-181a and PLXNC1 expression with transfection in A375 and M14 cells, cell viability, apoptosis, and invasive ability were evaluated using CCK-8, flow cytometry and Transwell assays, respectively. A low expression of CASC2 was detected in melanoma tissues and cells. Dual luciferase reporting assay confirmed that miR-181a targeted the 3'-UTR of PLXNC1. Furthermore, CASC2 could efficiently sponge miR-181a, thereby facilitating the expression of PLXNC1. Up-regulation of CASC2 suppressed the cell proliferation and invasion, but induced the apoptosis of melanoma cells. Our results demonstrated that lncRNA CASC2 can promote PLXNC1 expression by sponging miR-181a, thereby inhibiting the proliferation and invasion of melanoma cells, indicating that lncRNA CASC2 functions via the miR-181a/PLXNC1 axis in melanoma.

The charging events of the International Space Station have been a focus of concern in recent years. Hollow cathode plasma contactors were applied to control the floating potential for their high emission currents of amps order. The in flight measurements showed that the floating potential was much smaller than predicted originally, and the actual emitted currents by the plasma contactors were well below amps level. In such case, a simpler method to control the floating potential may be applicable and suggested in the paper. By application of a metal sphere, which is biased at a high negative voltage relative to the structure and used as an ion current collector, the electron charging current of the structure can be effectively neutralized and the structure׳s floating potential can be controlled nearly to zero. The mechanism is introduced and the constraint condition for the system is investigated. Finally, a range of parameters for design are presented. Typically, for 100 V high voltage array, a sphere of r =0.3–0.7 m and biased at 500–200 V is enough. For its simplicity, the method has obvious advantages, such as no requirement of working gas, high reliability and long life, etc.

Lithium-sulfur (Li-S) batteries are a promising candidate of next generation energy storage systems owing to its high theoretical capacity and energy density. However, to date, its commercial application was hindered by the inherent problems of sulfur cathode. Additionally, with the rapid decline of non-renewable resources and active appeal of green chemistry, the intensive research of new electrode materials was conducted worldwide. We have obtained a sheet-like carbon material (shaddock peel carbon sheets SPCS) from organic waste shaddock peel, which can be used as the conductive carbon matrix for sulfur-based cathodes. Furthermore, the raw materials are low-cost, truly green and recyclable. As a result, the sulfur cathode made with SPCS (SPCS-S), can deliver a high reversible capacity of 722.5 mAh g−1 at 0.2 C after 100 cycles with capacity recuperability of ~90%, demonstrating that the SPCS-S hybrid is of great potential as the cathode for rechargeable Li-S batteries. The high electrochemical performance of SPCS-S hybrid could be attributed to the sheet-like carbon network with large surface area and high conductivity of the SPCS, in which the carbon sheets enable the uniform distribution of sulfur, better ability to trap the soluble polysulfides and accommodate volume expansion/shrinkage of sulfur during repeated charge/discharge cycles.

This paper analyzes the factors influencing the optimal partition of a business process into subtasks to minimize the process cycle time. The paper develops a single-class open, queueing network model that incorporates the productivity gains due to the division of labor and the server time lost to coordination. An optimization model to minimize the cycle time subject to a maximum number of servers is presented. We derive an upper bound on the number of subtasks and present an algorithm to optimally solve the problem. We conduct an experimental analysis using the model to understand how the coordination time, process technology, and utilization affect the optimal division of labor. The model confirms that as the coordination time increases, the optimal number of subtasks decreases. Moreover, the results show the technology parameter has little effect when coordination is high, and if the utilization increases, then the optimal number of subtasks increases. The model and results provide a means to determine the optimal number of subtasks for a process.

The binding properties on alizarin to human serum albumin (HSA) have been studied for the first time using fluorescence spectroscopy in combination with UV-visible absorbance spectroscopy. The results showed that alizarin strongly quenched the intrinsic fluorescence of HSA through a static quenching procedure, and non-radiation energy transfer occurred within the molecules. The number of binding sites was 1, and the efficiency of Förster energy transfer provided a distance of 1.83 nm between tryptophan and alizarin binding site. ΔH(θ), ΔS(θ) and ΔG(θ) were obtained based on the quenching constants and thermodynamic theory (ΔH(θ)0, ΔS(θ)0 and ΔG(θ)0). These results indicated that hydrophobic and electrostatic interactions are the main binding forces in the alizarin-HSA system. In addition, the results obtained from synchronous fluorescence spectra and three-dimensional fluorescence spectra showed that the binding of alizarin with HSA could induce conformational changes in HSA.

The total time a patient spends in an outpatient facility, called the patient cycle time, is a major contributor to overall patient satisfaction. A frequently recommended strategy to reduce the total time is to perform some activities in parallel thereby shortening patient cycle time. To analyze patient cycle time this paper extends and improves upon existing multi-class open queueing network model (MOQN) so that the patient flow in an urgent care center can be modeled. Results of the model are analyzed using data from an urgent care center contemplating greater parallelization of patient care activities. The results indicate that parallelization can reduce the cycle time for those patient classes which require more than one diagnostic and/ or treatment intervention. However, for many patient classes there would be little if any improvement, indicating the importance of tools to analyze business process reengineering rules. The paper makes contributions by implementing an approximation for fork/join queues in the network and by improving the approximation for multiple server queues in both low traffic and high traffic conditions. We demonstrate the accuracy of the MOQN results through comparisons to simulation results.

Nano-TiO2 modified composites, including TiO2 + EP648 and M40/TiO2 + EP648, were fabricated, in which the nano-TiO2 particles were dispersed in an EP648 epoxy matrix using a high-speed shearing emulsification technique. A jet type of vacuum ultraviolet (VUV) source was used to simulate the VUV spectrum in space and acquire various doses of VUV irradiation. In terms of the changes in specific-area mass loss and surface morphology, the resistance to VUV irradiation of the TiO2 + EP648 and M40/TiO2 + EP648 nanocomposites was evaluated. Experimental results showed that compared to the EP648 epoxy and M40/EP648 composite, the specific-area mass loss of the TiO2 + EP648 was decreased by 44% and that of M40/TiO2 + EP648 composite by 38%, respectively. By increasing the dose of VUV irradiation, the internal layer shear strength of the M40/TiO2 + EP648 increased gradually, while that of the M40/EP648 showed a decreasing trend. After irradiation, the surface of the M40/TiO2 + EP648 changed a little, but that of the M40/EP648 was damaged severely. It was indicated by means of scanning electron microscopy and atomic force microscopy observations that the VUV damage occurred mainly in the epoxy matrix, while the carbon fibers showed good resistance to irradiation.

H5N1 avian influenza has caused serious economic losses as well as posed significant threats to public health, agriculture and wildlife. It is important to develop a rapid, sensitive and specific detection platform suitable for disease surveillance and control. In this study, a highly sensitive, specific and rapid biosensor based on polydiacetylene was developed for detecting H5 influenza virus. The polydiacetylene based biosensor was produced from an optimized ratio of 10,12-pentacosadiynoic acid and 1,2-dimyristoyl-snglycero-3-phosphocholine, with the anti-H5 influenza antibody embedded onto the vesicle surface. The optimized polydiacetylene vesicle could detect H5 influenza virus sensitively with a detection limit of 0.53 copies/mu L, showing a dramatic blue-to-red color change that can be observed directly by the naked eye and recorded by a UV-vis spectrometer. The sensitivity, specificity and accuracy of the biosensor were also evaluated. The sensor could specifically differentiate H5 influenza virus from H3 influenza virus, Newcastle disease virus and porcine reproductive and respiratory syndrome virus. Detection using tracheal swabs was in accord with virus isolation results, and comparable to the RT-PCR method. These results offer the possibility and potential of simple polydiacetylene based bio-analytical method for influenza surveillance. (C) 2015 Elsevier B.V. All rights reserved.

Mathematical model of atomic oxygen flux and fluence distribution is established for the spacecraft surface in low earth orbit space environment (LEO), which based on Monte Carlo ray tracing and domain decomposition methods(MCRT-DD). Spacecraft space geometry construction, number density and molecular thermal motion of atomic oxygen, spacecraft velocity affected by atmosphere co-rotation and orbit propagation parameters are considered fully in the model. The differential equation of flux is integrated with respect to the independent variables of molecular speed and the direction of the molecular velocity vector relative to the surface. Fluence along with the orbit propagation is integrated flux with time. Furthermore, those of maximum and minimum value and variation with alternating incidence angle are calculated. Simulated results showed the fluence distribution takes on the decreasing tendency greatly with the increasing incidence angle and the flux density reaches up to the maximum value in positive incidence angle and up to the minimum value in leeward incidence angle. The incidence angle is one of the great factors for flux and fluence distributions. The simulated results are in good agreement with the Long Duration Exposure Facility of National Aeronautics and Space Administration (LDEF-NASA) flight experiment data.

Increasing demand for higher voltage and power levels aboard spacecrafts requires space vacuum as insulator. A concerned issue for this is whether the outgassing of dielectric materials profusely used in spacecrafts can induce breakdown, and what, if it occurs, the mechanism and characteristics are. In this paper, low pressure breakdown induced by outgassing was investigated experimentally. It’s found that vacuum breakdown is significantly facilitated by the outgassing of dielectric materials. Measurements of Paschen’s curves for typical outgassing samples show that significant decrease of breakdown voltage occurs in high vacuum region due to increase of local pressure from outgassed products. Another important mechanism that affects the breakdown voltage is the electrode surface contamination by the outgassed components. Primary models with these mechanisms taken into account are described and the model calculations agree well with the measurements. Both experimental findings and theoretical analysis indicate that outgassing of space materials is a potentially important threat to high voltage systems with vacuum as insulation.