Studies on absorption coefficients of dual-energy γ-rays and measuring error correction for multiphase fraction determination

In tiffs article, principle and mathematical method of determining the phasc fractions of multiphase flows by using a dual-energy γ-ray system have been described. The dual-energy γ-ray device is composed of radioactive isotopes of ^241Am and ^137Cs with γ-ray energies of 59.5 and 662 keV, respectively. A rational method to calibrate the absorption coefficient was introduced in detail. The modified arithmetic is beneficial to removing the extra Compton scattering from the measured value. The result shows that the dual-energy γ-ray technique can be used in thrce-phase flow with average accuracy greater than 95%, which enables us to determine phase fractions almost independent of the flow regime. Improvement has been achicved on measurement accuracy of phase fractions.     

Differentiating computer experience and attitudes toward computers: an empirical investigation

The purpose of this study was to define and provide initial empirical support for differentiating the concepts of computer attitude, subjective computer experience and objective computer experience. A principal components factor analysis of computer attitude and computer experience scales was conducted on responses from 179 subjects. Results showed that objective computer experience was conceptually distinct from factors reflecting users' psychological reactions to computers. Results also provided partial support for differentiating the two constructs of computer attitude and subjective computer experience. Specifically, two factors emerged, the first reflecting Attitudes Toward Electronic Mail Use, and a second reflecting the separate construct of Autonomy/Assistance, an identifiable constituent of the Subjective Computer Experience Scale. The independent nature of these constructs should continue to be explored in future investigations with considerable attention being focused on the new construct, namely, Autonomy/Assistance. Suggestions for training and education are discussed, and a conceptual analysis of the relation between subjective computer experience and computer attitude presented. Hence, the current study provides a useful starting point for deciphering the precise nature of the relationship between computer attitude and subjective computer experience.     

Gas sensing properties of platinum dispersed-TiO2 thin film derived from precursor

Metal-organic precursor solution for coating glass substrates was synthesized using a Ti alkoxide derivative, amino acid, platinum salt and methanol as a solvent. Suitable addition of TiO₂ sol remarkably increased the gas sensitivity of the resultant platinum dispersed-TiO₂ thin film because of the formation of fine pores around nano-sized TiO₂ grains. A thin film fired at 450°C under a reducing atmosphere was not sensitive to reducing gases such as CO and CH₄, but revealed high selectivity and sensitivity to H₂ at 200°C. This thin film also showed high selectivity to trimethylamine (TMA) and NH₃. The selection of an appropriate starting metal-organic precursor and addition of titania sol were very effective in forming the desired microstructure with improved gas sensing properties.     

Amplitude based feedback control for NTM stabilisation at ASDEX Upgrade

Neoclassical Tearing Modes (NTMs) degrade the confinement in tokamak plasmas at high beta, placing a major limitation on the projected fusion performance. Furthermore, NTMs can lead to disruptions with even more severe consequences. Therefore methods to stabilise NTMs are being developed with high priority at several research institutes worldwide. The favoured method is to deposit Electron Cyclotron Current Drive (ECCD) precisely at the mode location by controlling a movable mirror in the ECCD launcher. This method requires both the mode location and the deposition location to be known with high accuracy in real time. The required accuracy is given by half of the marginal island width, or approximately 1 cm for a m/n = 3/2 NTM at ASDEX Upgrade. Despite considerable development on a range of diagnostics, it remains challenging to provide the necessary accuracy reliably and in real time.To relax the accuracy requirements and add robustness, the feedback controller can additionally consider the effect of ECCD on the NTM amplitude directly. Then the optimal deposition location is simply where the NTM amplitude is minimised. The simplest implementation sweeps the ECCD beam across the expected NTM location. After the sweep, the beam can be returned to the optimal location and held there to stabilise the NTM. Unfortunately, waiting for a full sweep takes too long. Therefore a second method assesses the NTM growth every 100 ms and hones in on the NTM in a series of steps. The two algorithms employ similar principles to the “Target Lock” and “Search & Suppress” algorithms implemented at DIII-D [1]. This paper presents the development of both algorithms using a simulation of the full feedback loop including NTM dynamics modelled by a Modified Rutherford Equation, and a demonstration of their effectiveness during ASDEX Upgrade experiments.     

Controllability study of EAST plasma vertical instability and improvement in future

In order to enhance control speed, each up/down Cu passive plate in EAST is cut into 8 pieces. These discontinuous plate segments are still connected to the inner vacuum vessel by steel supporting legs. A model of this plate segments-vessel-supporting leg loop is developed and verified by EAST vertical displacement event (VDE) experiments. The internal coil (IC) power supply requirements for VDE control are also evaluated. In particularly, we investigate the efficacy of internal control coil location to minimize the power supply capability. The IC power supply upgrade requirements for the optimized location and actual location are discussed. VDE experiments to evaluate maximum controllable vertical displacement (dZmax) were done with varying elongation and resulting EAST vertical controllability estimates are summarized here. These experimental results verified previous simulation results that present IC power supply capacity cannot provide robust vertical control.     

A new long-pulse data system for EAST experiments

A long pulse discharge requires high throughput data acquisition. As more physics diagnostics with high sampling rate are applied and the pulse length becomes longer, the original EAST (Experimental Advanced Superconducting Tokamak) data system no longer satisfies the requirements of real-time data storage and quick data access. A new system was established to integrate various data acquisition hardware and software for easy expansion and management of the system. Slice storage mechanism in MDSplus is now being used for the continuous and quasi real-time data storage. For every data acquisition thread and process, sufficient network bandwidth is ensured. Moreover, temporal digitized data is cached in computer memory in doubly linked circular lists to avoid the possible data loss by the occasional temporal storage or transfer jam. These data are in turn archived in MDSplus format by using slice storage mechanism called “segments”. For the quick access of the archived data to the users, multiple data servers are used. These data servers are linked using LVS (Linux Virtual server) load balance technology to provide a safe, highly scalable and available data service.     

Study of load balancing technology for EAST data management

With the continuous renewal and increasing number of diagnostics, the EAST tokamak routinely generates ∼3 GB of raw data per pulse of the experiment, which is transferred to a centralized data management system. In order to strengthen international cooperation, all the acquired data has been converted and stored in the MDSplus servers. During the data system operation, there are some problems when a lot of client machines connect to a single MDSplus data server. Because the server process keeps the connection until the client closes its connection, a lot of server processes use a lot of network ports and consume a large amount of memory, so that the speed of access to data is very slow, but the CPU resource is not fully utilized. To improve data management system performance, many MDSplus servers will be installed on the blade server and form a server cluster to realize load balancing and high availability by using LVS and heartbeat technology. This paper will describe the details of the design and the test results.     

Gadolinium‐Doped Iron Oxide Nanoprobe as Multifunctional Bioimaging Agent and Drug Delivery System

In this study, a high‐performance T₁–T₂ dual‐model contrast agent by gadolinium‐doped iron oxide nanoparticle (GION) is developed. Following its development, the application of this agent in vivo by combining doxorubicin (DOX) and folic acid (FA) (FA–GION–DOX) for targeted drug delivery to monitor cancer treatment is explored. GION showed transverse and longitudinal relaxivities up to 182.7 × 10^?3 and 7.87 × 10^?3m ^?1 s^?1, respectively, upon Gd/Fe ratio in GION at 1/4. DOX released from FA–GION–DOX is pH dependent and only kills cancer cell after FA receptor‐mediated internalization into the acidic environment of endosomes and lysosomes. Systemic delivery of FA–GION–DOX significantly inhibits the growth of tumors and shows good magnetic resonance enhancement in a human cervical cancer xenograft model. Thus, FA–GION–DOX has a potential application for the targeted and magnetic resonance imaging guided therapy of cervical cancer.     

Mare's and cow's milk: promote similar metabolic effects and expression of innate markers in Caco-2 cells?

Mare's milk (MM) is very similar to human breast milk, as it consists of low concentrations of proteins and fat and high concentrations of lactose. Thus, MM can be considered as an alternative to cow's milk (CM) for human nutrition. In this study, proteolytic resistant peptides to gastrointestinal enzymes were measured by reverse phase-high-performance liquid chromatography (RP-HPLC-PDA-UV) to determine their relative uptake by intestinal epithelial (Caco-2) cells. Alterations in mitochondrial enzyme activities (MTT test), inner mitochondrial membrane potential (ΔΨm), cell cycle progression and the expression (mRNA) of inflammatory (IL-1β, TNF-α and NF-κB) markers were studied. This is the first study comparing the effects of proteolytic resistant peptides from the whey proteins of mare's milk to those originating from cow's milk on intestinal cells. Similar proteolytic resistant peptide patterns, but lower uptake rates, were observed for MM peptides (7–40%) compared to peptides from CM (40–60%), although both types of peptides, probably derived from α-lactalbumin, were still capable of impairing ΔΨm in intestinal cells (CM > MM).Both MM and CM increased the expression of TNF-α, whereas IL-1β levels were not affected. CM increased NF-κB mRNA levels. Overall, our data indicate that proteolytic resistant peptides from both MM and CM exert similar metabolic effects on mitochondrial metabolism (up to 30%) in intestinal Caco-2 cells. However, the low uptake rates of peptides from MM may be beneficial to the human diet, an alternative to CM. Further in vivo studies are needed to better understand the potential clinical relevance of the control and/or regulation of metabolic processes related to perturbations in the gut immune system associated with lymphoid tissue.