Development of CONTHAC-3D and hydrogen distribution analysis of HPR1000

An in-house code,CONTHAC-3D,was developed to calculate and analyze thermal-hydraulic phenomena in containments during severe accidents.CONTHAC-3D is a three-dimensional computational fluid dynamics code that can be applied to predict gas flow,diffusion,and steam condensation in a containment during a severe hypothetical accident,as well as to obtain an estimate of the local hydrogen concentration in various zones of the containment.CONTHAC-3D was developed using multiple models to simulate the features of the proprietary systems and equipment of HPR1000 and ACP100,such as the passive cooling system,passive autocatalytic recombiners and the passive air cooling system.To validate CONTHAC-3D,a GX6 test was performed at the Battelle Model Containment facility.The hydrogen concentration and temperature monitored by the GX6 test are accurately predicted by CONTHAC-3D.Subsequently,the hydrogen distribution in the HPR1000 containment during a severe accident was studied.The results show that the hydrogen removal rates calculated using CONTHAC-3D for different types of PARs agree well with the theoretical values,with an error of less than 1%.As the accident progresses,the hydrogen concentration in the lower compartment becomes higher than that in the large space,which implies that the lower compartment has a higher hydrogen risk than the dome and large space at a later stage of the accident.The amount of hydrogen removed by the PARs placed on the floor of the compartment is small;therefore,raising the installation height of these recombiners appropriately is recommended.However,we do not recommend installing all autocatalytic recombiners at high positions.The study findings in regard to the hydrogen distribution in the HPR1000 containment indicate that CONTHAC-3D can be applied to the study of hydrogen risk containment.

Pit-and trench-forming osteoclasts:a distinction that matters

Osteoclasts（OCs）seeded on bone slices either drill round pits or dig long trenches.Whereas pits correspond to intermittent resorption,trenches correspond to continuous and faster resorption and require a distinct assembly of the resorption apparatus.It is unknown whether the distinction between pits and trenches has any biological relevance.Using OCs prepared from different blood donors,we found that female OCs achieved increased resorption mainly through pit formation,whereas male OCs did so through trench formation.Trench formation went along with high collagenolytic activity and high cathepsin K（CatK）expression,thereby allowing deeper demineralization.A specific CatK inhibitor abrogated the generation of trenches,while still allowing the generation of pits.OCs obtained from bone marrow were more prone to generate trenches than those obtained from blood.Scanning electron microscopy of bone surfaces eroded in vivo showed trenches and pits of similar size as those made by OCs in culture.We conclude that the distinction between trench-and pit-forming OCs is relevant to the differences among OCs from different skeletal sites,different individuals,including gender,and results from differences in colIagenolytic power.This indicates a biological relevance and highlights the importance of discriminating between pits and trenches when assessing resorption.

Numerical analysis of heat transfer enhancement on steam condensation in the presence of air outside the tube

In loss-of-coolant accidents,a passive containment heat removal system protects the integrity of the containment by condensing steam.As a large amount of air exists in the containment,the steam condensation heat transfer can be significantly reduced.Based on previous research,traditional methods for enhancing pure steam condensation may not be applicable to steam–air condensation.In the present study,new methods of enhancing condensation heat transfer were adopted and several potentially enhanced heat transfer tubes,including corrugated tubes,spiral fin tubes,and ring fin tubes were designed.STAR-CCM+was used to determine the effect of enhanced heat transfer tubes on the steam condensation heat transfer.According to the calculations,the gas pressure ranged from 0.2 to 1.6 MPa,and air mass fraction ranged from 0.1 to 0.9.The effective perturbation of the high-concentration air layer was identified as the key factor for enhancing steam–air condensation heat transfer.Further,the designed corrugated tube performed well at atmospheric pressure,with a maximum enhancement of 27.4%,and performed poorly at high pressures.In the design of spiral fin tubes,special attention should be paid to the locations that may accumulate high-concentration air.Nonetheless,the ring-fin tubes generally displayed good performance under all conditions of interest,with a maximum enhancement of 24.2%.

Transverse relaxation determination based on light polarization modulation for spin-exchange relaxation free atomic magnetometer

A transverse relaxation determination of spin-exchange relaxation free （SERF） magnetometer based on polarization modulation technique is proposed. Compared with the radio-frequency （RF） excitation and light intensity excitation meth- ods used in SERF magnetometer, the light polarization modulation method has a high stability in low-frequency range, which indicates a more accurate transverse relaxation measurement.

Research on Hidden Failure Reliability Modeling of Electric Power System Protection

Aiming at digital relay protection system, a novel hidden failure Markov reliability model is presented for a single main protection and double main protection systems according to hidden failure and protection function under Condition-Based Maintenance (CBM) circumstance and reliability indices such as probability of protection system hidden failure state are calculated. Impacts of different parameters (containing impacts of human errors) to hidden failure state probability and the optimal measures to improve reliability by variable parameter method are also analyzed. It’s demonstrated here that: Compared to a single main protection, double main protection system has an increased hidden failure probability, thus the real good state probability decreases, two main protections’ reliability must be improved at the same time, so configuration of the whole protection system for the component being protected can’t be complicated. Through improving means of on-line self-checking and monitoring system in digital protection system and human reliability, the real application of CBM can decrease hidden failure state probability. Only through this way can we assure that the protection systems work in good state. It has a certain reference value to protection system reliability engineering.

Research on the Topology and Control Scheme of an Innovative Modular Multilevel Converter

This paper presents a new modular multilevel converter (MMC) topology. Compared to conventional multilevel converters, MMC has much lower switching frequency (50 Hz) resulting in lower switching losses, and consequently, lower total losses of the transmission system. The fundamental concept and the applied control scheme are introduced in detail. A modified multilevel fundamental switching modulation scheme adopting the multicarrier pulse width modulation concept is presented. A capacitor voltage balancing technique is proposed. With the established simulation model of the 11-level MMC, the modulation and balancing strategy presented are confirmed by MATLAB/SIMULINK simulations. The multicarrier pulse width modulation converter strategy enhances the fundamental output voltage and reduces total harmonic distortion. This new type of converter is suitable for high-voltage drive systems and power system applications such as high voltage dc (HVDC) transmission, reactive power compensation equipment and so on.

Business Process Dynamic Reengineering Technology Based on Mode

To ensure the efficiency and quality of complex business process design,a mode-based dynamic business process reengineering approach is proposed in this paper.Firstly,the composition of business process is divided into five levels.Business process modes from three levels of mission,content and resource are defined,and the transition relationships between modes are given.Secondly,the architecture model of business process is defined based on the architecture analysis and design language(AADL).The dynamic reengineering framework and implementation procedure are designed.Finally,the AADL architecture models are analyzed and verified to evaluate the business process performance,and a blueprint for reengineering is formulated.Under the guidance of the blueprint,the detailed design and development of attributes such as business processes,activities,resources and cost are completed.Case studies are presented to validate that the mode analysis and dynamic reengineering approach based on the AADL architecture is able to improve the efficiency,reliability and reusability of business process design.

纤维结合蛋白在角膜伤口愈合中的应用

纤维结合蛋白是一种细胞外结构蛋白,具有结合细胞和胶原的独特能力,在角膜发育中起重要作用。角膜创伤8小时内,纤维结合蛋白常规地出现,这一现象已经引起了人们对其创伤愈合特性的极大兴趣。在纤维结合蛋白用于复发性角膜糜烂和某些类型的干燥性角膜炎的治疗中,早期临床应用,效果明显。现阶段妨碍纤维结合蛋白投入商业用途的主要问题是不同种类的纤维结合蛋白的抗原性。人造纤维结合蛋白已被建议作为这种普遍存在的蛋白质的商业来源。

Compound-induced transparency in three-cavity coupled structure

We propose a three-cavity coupled cavity optomechanical(COM)structure with tunable system parameters and theoretically investigate the probe-light transmission rate.Numerical calculation of the system’s spectra demonstrates distinctive compound-induced transparency(CIT)characteristics,including multiple transparency windows and sideband dips,which can be explained by a coupling between optomechanically-induced transparency(OMIT)and electromagnetically-induced transparency.The effects of optical loss(gain)in the cavity,number and topology of active cavity,tunneling ratio,and pump laser power on the CIT spectrum are evaluated and analyzed.Moreover,the optical group delay of CIT is highly controllable and fast–slow light inter-transition can be achieved.The proposed structure makes possible the advantageous tuning freedom and provides a potential platform for controlling light propagation and fast–slow light switching.

Hybrid Network Model Based on Data Enhancement for Short-term Power Prediction of New PV Plants

This study proposes a hybrid network model based on data enhancement to address the problem of low accuracy in photovoltaic(PV)power prediction that arises due to insuffi cient data samples for new PV plants.First,a time-series gener ative adversarial network(TimeGAN)is used to learn the distri bution law of the original PV data samples and the temporal correlations between their features,and these are then used to generate new samples to enhance the training set.Subsequently,a hybrid network model that fuses bi-directional long-short term memory(BiLSTM)network with attention mechanism(AM)in the framework of deep&cross network(DCN)is con structed to effectively extract deep information from the origi nal features while enhancing the impact of important informa tion on the prediction results.Finally,the hyperparameters in the hybrid network model are optimized using the whale optimi zation algorithm(WOA),which prevents the network model from falling into a local optimum and gives the best prediction results.The simulation results show that after data enhance ment by TimeGAN,the hybrid prediction model proposed in this paper can effectively improve the accuracy of short-term PV power prediction and has wide applicability.

Reliability Assessment of Interconnected Power Systems with HVDC Links Considering Frequency Regulation Process

With various components and complex topologies,the applications of high-voltage direct current(HVDC)links bring new challenges to the interconnected power systems in the aspect of frequency security,which further influence their reliability performances.Consequently,this paper presents an approach to evaluate the impacts of the HVDC link outage on the reliability of interconnected power system considering the frequency regulation process during system contingencies.Firstly,a multi-state model of an HVDC link with different available loading rates(ALRs)is established based on its reliability network.Then,dynamic frequency response models of the interconnected power system are presented and integrated with a novel frequency regulation scheme enabled by the HVDC link.The proposed scheme exploits the temporary overload capability of normal converters to compensate for the imbalanced power during system contingencies.Moreover,it offers frequency support that enables the frequency regulation reserves of the sending-end and receiving-end power systems to be mutually available.Several indices are established to measure the system reliability based on the given models in terms of abnormal frequency duration,frequency deviation,and energy losses of the frequency regulation process during system contingencies.Finally,a modified two-area reliability test system(RTS)with an HVDC link is adopted to verify the proposed approach.

Integrated Planning of an Active Distribution Network and DG Integration in Clusters Considering a Novel Formulation for Reliability Assessment

The concept of DG clusters is introduced with highly penetrated integration of distributed generation(DG)into active distribution networks(ADNs).DG clusters are referred to as parts of an ADN,including DGs,distribution lines and loads.The formation of DG clusters helps to optimally dispatch DG outputs within ADNs.In this regard,an integrated planning strategy of ADNs and DGs in cluster(IPNDGC)is proposed.In order to guarantee that the planning strategy meets the reliability requirements,a reliability assessment is considered in the proposed model.However,reliability assessment is generally accomplished according to a fixed network topology and known DG allocation,which makes it difficult to integrate reliability into planning models.To deal with this difficulty,a novel formulation method for reliability assessment is proposed considering the network topology uncertainties and isolated operating probabilities of DG clusters.The reliability index(RI)represented by expected customer interruption cost(ECOST)is employed in the proposed planning model.The planning model is formulated as a mixed integer second order conic programming planning model.An actual distribution system is employed to illustrate the accuracy and efficiency of the proposed planning model.

Recursive formulas for the Kronecker quantum cluster algebra with principal coefficients

We use the quantum version of Chebyshev polynomials to explicitly construct the recursive formulas for the Kronecker quantum cluster algebra with principal coefficients.As a byproduct,we obtain two barinvariant positive ZP-bases with one being the atomic basis.

Vitamin D receptor (VDR) mediates the quiescence of activated hepatic stellate cells (aHSCs) by regulating M2 macrophage exosomal smooth muscle cell-associated protein 5 (SMAP-5)

An effective therapeutic regimen for hepatic fibrosis requires a deep understanding of the pathogenesis mechanism.Hepatic fibrosis is characterized by activated hepatic stellate cells(aHSCs)with an excessive production of extracellular matrix.Although promoted activation of HSCs by M2 macrophages has been demonstrated,the molecular mechanism involved remains ambiguous.Herein,we propose that the vitamin D receptor(VDR)involved in macrophage polarization may regulate the communication between macrophages and HSCs by changing the functions of exosomes.We confirm that activating the VDR can inhibit the effect of M2 macrophages on HSC activation.The exosomes derived from M2 macrophages can promote HSC activation,while stimulating VDR alters the protein profiles and reverses their roles in M2 macrophage exosomes.Smooth muscle cell-associated protein 5(SMAP-5)was found to be the key effector protein in promoting HSC activation by regulating autophagy flux.Building on these results,we show that a combined treatment of a VDR agonist and a macrophage-targeted exosomal secretion inhibitor achieves an excellent anti-hepatic fibrosis effect.In this study,we aim to elucidate the association between VDR and macrophages in HSC activation.The results contribute to our understanding of the pathogenesis mechanism of hepatic fibrosis,and provide potential therapeutic targets for its treatment.

Real-world validation of the chemotherapy-induced nausea and vomiting predictive model and its optimization for identifying high-risk Chinese patients

To the Editor:Chemotherapy-induced nausea and vomiting(CINV)is the most common and feared side effect reported by patients receiving chemotherapy.Despite significant progress,the incidence of CINV remains high.[1]Prevention is the key for controlling CINV.Evidence-based antiemetic guidelines recommend that strategies to prevent CINV should consider both the emetic risk of chemotherapeutic agents and patients’individual risk factors.[2]To date,several personal factors predicting a high risk of CINV have been identified,including expectancy of CINV.

Role of the Anterior Cingulate Cortex in Translational Pain Research

As the most common symptomatic reason to seek medical consultation,pain is a complex experience that has been classified into different categories and stages.In pain processing,noxious stimuli may activate the anterior cingulate cortex(ACC).But the function of ACC in the different pain conditions is not well discussed.In this review,we elaborate the commonalities and differences from accumulated evidence by a variety of pain assays for physiological pain and pathological pain including inflammatory pain,neuropathic pain,and cancer pain in the ACC,and discuss the cellular receptors and signaling molecules from animal studies.We further summarize the ACC as a new central neuromodulation target for invasive and non-invasive stimulation techniques in clinical pain management.The comprehensive understanding of pain processing in the ACC may lead to bridging the gap in translational research between basic and clinical studies and to develop new therapies.

Optical Rotation Detection for Atomic Spin Precession Using a Superluminescent Diode

A superluminescent diode (SLD) as an alternative of laser is used to detect optical rotation for atomic spin precession. A more uniform Gauss configuration without additional beam shaping and a relatively high power of the SLD have a potential for atomic magnetometers, which is demonstrated in theory and experiments. In addition, the robustness and compactness enable a more practical way for optical rotation detections, especially for applications in magnetoencephalography systems.

Distributed cooperative voltage control based on curve-fitting in active distribution networks

This study investigates a hybrid hierarchical multi-agent system for distributed cooperative voltage control in active distribution networks. The hybrid hierarchical multi-agent system adopts on-load tap-changing(OLTC) agents for the distribution transformers and feeder control section(FCS) agents for the distributed generators(DGs). The objective is to minimize the voltage deviations over the network. The FCS agents also have the objective of minimizing reductions in DG power output. A least squares method is used for curve fitting to achieve the two objectives. The OLTC agent receives voltage information from the FCS agents to evaluate the state of the voltage in each feeder and the distribution network and cooperates with the FCS agents to control the voltage of the network.The FCS agents exchange the fitted curve parameters and basic information on the DGs with other agents to achieve the objectives. The effectiveness of the proposed distributed cooperative voltage control scheme is verified through simulations. Depending on the network voltages obtained by the OLTC agent, different operations are executed to prevent voltage limit violations and to minimize the voltage deviations and reductions in the DG power outputs.

Bases of the Quantum Cluster Algebra of the Kronecker Quiver

We construct bar-invariant Z[q ±1/2]-bases of the quantum cluster algebra of Kronecker quiver which are quantum analogues of the canonical basis, semicanonical basis and dual semicanonical basis of the corresponding cluster algebra. As a byproduct, we prove positivity of the elements in these bases.

Noise reduction and signal to noise ratio improvement in magneto-optical polarization rotation measurement

The measurement of an extremely small magneto-optical polarization rotation angle with high sensitivity is integral to many scientific and technological applications. In this Letter, we have presented a technique based on Faraday modulation combined with the optical differential method to measure an extremely small polari- zation rotation angle with high sensitivity. The theoretical and experimental results show that common mode noise is reduced appreciably and signal to noise ratio is enhanced. The effectiveness of this technique has been demonstrated by measuring the Verdet constant of terbium gallium garnet glass and measuring the small polari- zation rotation angle. A sensitivity of enhancement of one order of magnitude has been achieved using differ- ential detection based on Faraday modulation.