Investigation on the Natural Modes of A Semi-Closed Floating Tank

Vessels with semi-closed tanks(i.e.,well docks)are widely applied in the military operation and maritime engineer-ing.The water is bound by the semi-closed floating tank and forced by both the incident waves and ship’s motions.The free surface oscillations inside the flooded well dock is thus distinctive and very complicated.So far,the natural modes of semi-closed floating tanks have not yet been studied.This paper investigates the characteristics of natural modes of a floating semi-closed tank by combining a mode-resolving model based on mild-slope equations and a hydrodynamic model based on computational fluid dynamics.Results show that the first three natural periods(i.e.,74,23.6,and 14 s)of the tank fall into the band of swell and infragravity waves and they could be triggered under certain circumstance.Multi-period free surface oscillations are observed inside the tank,including the longest natural period(i.e.,74 s),though the incident waves are monochromatic.A possible generation mechanism for the long-period mode is explained on the basis of liquid sloshing and harbor oscillations.Moreover,a long-period component with a period close to the natural mode of well dock is observed in the ship motions,which is generated by the interaction between the waves and ship.

Long non-coding RNA H19 regulates neurogenesis of induced neural stem cells in a mouse model of closed head injury

Stem cell-based therapies have been proposed as a potential treatment for neural regeneration following closed head injury.We previously reported that induced neural stem cells exert beneficial effects on neural regeneration via cell replacement.However,the neural regeneration efficiency of induced neural stem cells remains limited.In this study,we explored differentially expressed genes and long non-coding RNAs to clarify the mechanism underlying the neurogenesis of induced neural stem cells.We found that H19 was the most downregulated neurogenesis-associated lnc RNA in induced neural stem cells compared with induced pluripotent stem cells.Additionally,we demonstrated that H19 levels in induced neural stem cells were markedly lower than those in induced pluripotent stem cells and were substantially higher than those in induced neural stem cell-derived neurons.We predicted the target genes of H19 and discovered that H19 directly interacts with mi R-325-3p,which directly interacts with Ctbp2 in induced pluripotent stem cells and induced neural stem cells.Silencing H19 or Ctbp2 impaired induced neural stem cell proliferation,and mi R-325-3p suppression restored the effect of H19 inhibition but not the effect of Ctbp2 inhibition.Furthermore,H19 silencing substantially promoted the neural differentiation of induced neural stem cells and did not induce apoptosis of induced neural stem cells.Notably,silencing H19 in induced neural stem cell grafts markedly accelerated the neurological recovery of closed head injury mice.Our results reveal that H19 regulates the neurogenesis of induced neural stem cells.H19 inhibition may promote the neural differentiation of induced neural stem cells,which is closely associated with neurological recovery following closed head injury.

Induced neural stem cells regulate microglial activation through Akt-mediated upregulation of CXCR4 and Crry in a mouse model of closed head injury

Microglial activation that occurs rapidly after closed head injury may play important and complex roles in neuroinflammation-associated neuronal damage and repair.We previously reported that induced neural stem cells can modulate the behavior of activated microglia via CXCL12/CXCR4 signaling,influencing their activation such that they can promote neurological recovery.However,the mechanism of CXCR4 upregulation in induced neural stem cells remains unclear.In this study,we found that nuclear factor-κB activation induced by closed head injury mouse serum in microglia promoted CXCL12 and tumor necrosis factor-αexpression but suppressed insulin-like growth factor-1 expression.However,recombinant complement receptor 2-conjugated Crry(CR2-Crry)reduced the effects of closed head injury mouse serum-induced nuclear factor-κB activation in microglia and the levels of activated microglia,CXCL12,and tumor necrosis factor-α.Additionally,we observed that,in response to stimulation(including stimulation by CXCL12 secreted by activated microglia),CXCR4 and Crry levels can be upregulated in induced neural stem cells via the interplay among CXCL12/CXCR4,Crry,and Akt signaling to modulate microglial activation.In agreement with these in vitro experimental results,we found that Akt activation enhanced the immunoregulatory effects of induced neural stem cell grafts on microglial activation,leading to the promotion of neurological recovery via insulin-like growth factor-1 secretion and the neuroprotective effects of induced neural stem cell grafts through CXCR4 and Crry upregulation in the injured cortices of closed head injury mice.Notably,these beneficial effects of Akt activation in induced neural stem cells were positively correlated with the therapeutic effects of induced neural stem cells on neuronal injury,cerebral edema,and neurological disorders post–closed head injury.In conclusion,our findings reveal that Akt activation may enhance the immunoregulatory effects of induced neural stem cells on microglial activation via upregulation of CXCR4 and Crry,thereby promoting induced neural stem cell–mediated improvement of neuronal injury,cerebral edema,and neurological disorders following closed head injury.

On Fuzzy Regularly Closed Filters in Michálek Fuzzy Topological Space

C.L. Chang’s introduction of fuzzy topology in 1981 opened up new avenues for parallel theories in topology. However, Chang’s work appears to focus more on the topology of fuzzy sets rather than fuzzy topology itself. In 1975, Michálek presented a functional definition of ordinary topology and later developed fuzzy topology as a distinct extension of this idea, setting it apart from Chang’s approach. While there has been significant research on Chang’s fuzzy topology, Michálek’s version has not received as much attention. This paper introduces the concept of fuzzy regularly closed filters, or FRCM filters, within Michálek’s fuzzy topological space and explores some properties of FRCM ultrafilters.

Sensing-Communication-Computing-Control Closed Loop for NOMA-UAV Systems

In the areas without terrestrial communication infrastructures,unmanned aerial vehicles(UAVs)can be utilized to serve field robots for mission-critical tasks.For this purpose,UAVs can be equipped with sensing,communication,and computing modules to support various requirements of robots.In the task process,different modules assist the robots to perform tasks in a closed-loop way,which is referred to as a sensing-communication-computing-control(SC3)loop.In this work,we investigate a UAV-aided system containing multiple SC^(3)loops,which leverages non-orthogonal multiple access(NOMA)for efficient resource sharing.We describe and compare three different modelling levels for the SC^(3)loop.Based on the entropy SC^(3)loop model,a sum linear quadratic regulator(LQR)control cost minimization problem is formulated by optimizing the communication power.Further for the assure-to-be-stable case,we show that the original problem can be approximated by a modified user fairness problem,and accordingly gain more insights into the optimal solutions.Simulation results demonstrate the performance gain of using NOMA in such task-oriented systems,as well as the superiority of our proposed closed-loop-oriented design.

Design and Test of Closed Hydraulic Transmission System of 4WD High-clearance Wheeled Sprayer

In conjunction with the working characteristics of the high-clearance wheeled sprayer and the benefits of the closed hydraulic system,a series of reasonable working parameters should be established,and a hydraulic system that fulfills the requisite specifications should be designed.The AMESim software model is employed to construct a closed hydraulic transmission system,and the simulation analysis is then performed according to the data of hydraulic components.According to analysis results,the prototype can be optimized and upgraded,and a verification test is further carried out.The test results demonstrate that the designed closed hydraulic transmission system meets the actual working requirements of the high-clearance wheeled sprayer and provides a stable experimental platform for intelligent control of agricultural machinery.

Simulation Modelling and Techno-Economics of Supercritical Carbon Dioxide Recompression Closed Brayton Cycle

In recent years, there has been global interest in meeting targets relating to energy affordability and security while taking into account greenhouse gas emissions. This has heightened major interest in potential investigations into the use of supercritical carbon dioxide (sCO2) power cycles. Climate change mitigation is the ultimate driver for this increased interest;other relevant issues include the potential for high cycle efficiency and a circular economy. In this study, a 25 MWe recompression closed Brayton cycle (RCBC) has been assessed, and sCO2 has been proposed as the working fluid for the power plant. The methodology used in this research work comprises thermodynamic and techno-economic analysis for the prospective commercialization of this sCO2 power cycle. An evaluated estimation of capital expenditure, operational expenditure, and cost of electricity has been considered in this study. The ASPEN Plus simulation results have been compared with theoretical and mathematical calculations to assess the performance of the compressors, turbine, and heat exchangers. The results thus reveal that the cycle efficiency for this prospective sCO2 recompression closed Brayton cycle increases (39% - 53.6%) as the temperature progressively increases from 550˚C to 900˚C. Data from the Aspen simulation model was used to aid the cost function calculations to estimate the total capital investment cost of the plant. Also, the techno-economic results have shown less cost for purchasing equipment due to fewer components being required for the cycle configuration as compared to the conventional steam power plant.

Semi-closed synthesis of nitrogen and oxygen Co-doped mesoporous carbon for selective aqueous oxidation

Heteroatom-doped meso/micro-porous carbon materials are conventionally produced by harsh carbonization under an inert atmosphere involving specific precursors,hard/soft templates,and heteroatom-containing agents.Herein,we report a facile synthesis of N and O co-doped meso/micro-porous carbon(NOMC)by template-free carbonization of a small-molecule precursor in a semi-closed system.The semi-closed carbonizaiton process yields hydrophilic NOMCs with large surface area in a high yield.The porous structure as well as the elemental composition of NOMCs can be modulated by changing the holding time at a particular temperature.NOMCs as metal-free heterogeneous catalysts can selectively oxidize benzyl alcohol and its derivatives into aldehydes/ketones with>85%conversion in aqueous solution,which is much higher than that of the control sample obtained in tube furnace(21%conversion),mainly due to their high N content,high percentage of pyridinic N,and large surface area.The presence of O-containing moieties also helps to improve the hydrophilicity and dispersion ability of catalysts and thus facilitates the mass transfer process during aqueous oxidation.The NOMC catalysts also dispayed excellent activity for a wide range of substrates with a selectivity of>99%.

Study on Deposition in Semi-Closed Coastal or Estuarine Harbour Basins

A preliminary study on the distribution of sediment transport and siltation within a semi-closed harbour as well as the factors affecting the siltation has been made with a suspended sediment model, in which the Lianyungang port is used as the prototype. Based on the work, this paper describes a tubid water experiment within a typical excavated harbour basin. According to the experimental results some expressions for predicting the average siltation amount for semi-closed harbour basins by means of dimensional analysis have been proposed, with tidal features, harbour geometry and properties of sediment taken into account. Through comparing the calculated results with the laboratory and field measured data, it has been shown that the expressions presented in this paper are reasonable.

Effect of periodic wide atmospheric pressure change on CO emission in closed goaf

Atmospheric pressure fuctuation is one of the most important factors afecting the climate environment and gas emission in the fre area.To obtain the infuence rule of the surface atmospheric pressure change on the gas sampling and abnormal emission in the mine closed goaf,the No.1 coal mine in Dananhu was taken as the research object.Using Fourier transform and Fisher harmonic analysis and other statistical methods,the infuence of the periodic variation of atmospheric pressure on the gas leakage and outfow in the closed goaf was studied.The results showed that there were three atmospheric pressure periods of 15.2 d,1 d and 182.2 d,and the probability was greater than 95%.The time period with the highest number of atmospheric pressure peaks was 7:00–8:00,which accounted for 20.2%of total occurrence number in a day.And the time periods with the highest number of atmospheric pressure trough were 2:00,15:00 and 16:00,accounting for 27.4%.The peak-to-trough transition time was mainly concentrated around 6 h,and the diurnal variation curve of atmospheric pressure was mainly bimodal.The atmospheric pressure change rate was mostly concentrated in 10–50 Pa/h.It was determined that the distance that the gas sampling pipe was pre-laid into the inner side of the closed wall should be greater than 44.4 m,and the CO concentration and atmospheric pressure in the closed goaf were both periodic and negative with atmospheric pressure.The research results have important guiding signifcance for the monitoring,early warning and environmental protection of the goaf.

Performance analyses of two-phase closed thermosyphons for road embankments in the high-latitude permafrost regions

Two-phase closed thermosyphons(TPCTs)are widely used in infrastructure constructions in permafrost regions.Due to different climatic conditions,the effectiveness of TPCT will also be different,especially in the extremely cold region of the Da Xing'anling Mountains.In this study,a series of three-dimensional finite element TPCT embankment models were established based on the ZhanglingMohe highway TPCT test section in Da Xing'anling Mountains,and the thermal characteristics and the cooling effect of the TPCTs were analyzed.The results indicated that the TPCTs installed in the northeastern high-latitude regions is effective in cooling and stabilizing the embankment.The working cycle of the TPCTs is nearly 7 months,and the cooling range of the TPCTs can reach 3 m in this region.However,due to the extremely low temperature,the TPCT generates a large radial gradient in the permafrost layer.Meanwhile,by changing the climate conditions,the same type of TPCT embankment located in the Da Xing'anling Mountains,the Xiao Xing'anling Mountains,and the Qinghai-Tibet Plateau permafrost regions were simulated.Based on the comparison of the climate differences between the Qinghai-Tibet Plateau and Northeast China,the differences in the effectiveness of TPCTs were studied.Finally,the limitations of using existing TPCTs in high-latitude permafrost regions of China were discussed and the potential improvements of the TPCT in cold regions were presented.

Closed corner divertor with B×▽B away from the divertor:a promising divertor scenario for tokamak power exhaust

A major challenge facing the steady-state operation of tokamak fusion reactors is to develop a viable divertor solution with order-of-magnitude increase in power handling capability as compared with present experience.A recently developed divertor concept for this end has been tested recently on EAST tokamak through combining the effects of a closed divertor corner and E×B drifts.The E×B drifts in the divertor move particles towards the outer divertor corner area in the scrape-off layer for B×▽B directed away from the divertor,which can significantly enhance the particle concentration there,facilitating divertor detachment.In recent EAST experiments,the effects have been demonstrated where the lowest electron temperature at the divertor plate is obtained with strike point located close to the corner in the horizontal target and with B×▽B away from the divertor.These experimental results are in reasonable agreement with SOLPS-ITER simulations including drift effects,suggesting that the new divertor concept potentially provides a promising divertor solution for long-pulse operations of future tokamak fusion reactors with much higher power fluxes.

Parameter Design of Current Double Closed Loop for T-Type Three-Level Grid-Connected Inverter

To reduce current harmonics caused by switching frequency,T-type grid-connected inverter topology with LCL filter is adopted.In view of the disadvantages of the slow response speed of the traditional current control and the failure to eliminate the influence of the LCL filter on the grid-connected current by using current PI control alone,a current double closed loop PI current tracking control is proposed.Through the theoretical analysis of the grid-connected inverter control principle,the grid-connected inverter control model is designed,and the transfer functionmodel of each control link is deduced,and the current loop PI regulator is designed at last.The simulation results show that the control strategy is feasible.

Meta-analysis of the efficacy of volar plate internal fixation versus closed reduction and external fixation in the treatment of adult distal radius fractures

Objective:To compare the efficacy of open reduction and volar locking plate internal fixation with closed reduction and external fixation in the treatment of distal radius fractures by using meta analysis.Methods:The databases of CNKI,Wanfang,Weipu,Chinese biomedical literature,Pubmed,Embase,and Cochrane Library were retrieved,and the randomized controlled studies that directly compared the efficacy of plate internal fixation and closed reduction external fixation in the treatment of distal radius fractures published publicly from the establishment of the database to April 2023 were collected.The two researchers independently screened the retrieved literature according to the inclusion and exclusion criteria,extracted data,used Cochrane risk bias assessment tool for quality assessment,and used RevMan 5.4 software for meta analysis.Results:A total of 10 randomized controlled trials were included,all of which were in English.There were 1042 patients in total,and 9 of them were rated as low risk.Meta analysis results showed that one year after the treatment of distal radius fracture with volar locking plate internal fixation,DASH score[MD=-5.64,95%CI(-7.21,-4.06),P<0.00001];One year later,PRWE score[MD=-5.90,95%CI(-8.88,-2.92),P=0.001];Palm flexion[MD=5.92,95%CI(1.29,10.55),P=0.01];Pronation[MD=2.48,95%CI(0.59,4.36),P=0.01];Postrotation[MD=4.73,95%CI(2.15,7.31),P=0.0003];Grip strength[MD=0.61,95%CI(0.12,1.10),P=0.02];palmar tilt angle[MD=9.84,95%CI(5.66,14.02),P<0.00001];Radial inclination[MD=4.33,95%CI(2.97,5.69),P<0.00001]was superior to closed reduction plaster or splint external fixation.One year later,the European Five dimensional Health Scale(EQ-5D-5L)score[MD=0.02,95%CI(-0.01,0.05),P=0.27];Back extension[MD=2.22,95%CI(-4.15,8.59),P=0.49];Ulnar deviation[MD=3.49,95%CI(-0.80,7.78),P=0.11];Radial deviation[MD=2.05,95%CI(-2.39,6.50),P=0.37];Ulnar variance[MD=-1.14,95%CI(-3.16,0.88),P=0.27];There was no significant difference in complications[MD=0.77,95%CI(0.54,1.10),P=0.16](P>0.05).Conclusion:Based on the current clinical data,internal fixation with volar locking plate is more conducive to mid-term DASH score and grip strength recovery than closed reduction plaster or splint external fixation,but there is no significant difference in the quality of life and complications of patients.For adult distal radius fractures,surgical indications should be carefully grasped,and non operative treatment should be given priority.

Design and analysis of an advanced thermal management system for the solar close observations and proximity experiments spacecraft

In this paper,the mission and the thermal environment of the Solar Close Observations and Proximity Experiments(SCOPE)spacecraft are analyzed,and an advanced thermal management system(ATMS)is designed for it.The relationship and functions of the integrated database,the intelligent thermal control system and the efficient liquid cooling system in the ATMS are elaborated upon.For the complex thermal field regulation system and extreme space thermal environment,a modular simulation and thermal field planning method are proposed,and the feasibility of the planning algorithm is verified by numerical simulation.A solar array liquid cooling system is developed,and the system simulation results indicate that the temperatures of the solar arrays meet the requirements as the spacecraft flies by perihelion and aphelion.The advanced thermal management study supports the development of the SCOPE program and provides a reference for the thermal management in other deep-space exploration programs.

Factors Associated with Closely Spaced Pregnancies at the Departmental Hospital Centre of Zou-Collines (Benin) in 2022

Introduction: Birth spacing to prevent closely-spaced pregnancies, which are a source of maternal and neonatal morbidity and mortality, is not always respected by our women, as recommended by the World Health Organization (WHO). The objective was to study the factors associated with closely-spaced pregnancies among women followed at the Departmental Hospital Center du Zou et du Colline (DHC/Z-C) in 2022. Study Method: This was a descriptive, analytical cross-sectional study with prospective data collection from 20 May to 30 June 2022. Results: At the end of the study, 83 of the 117 women surveyed had close pregnancies, a frequency of 70.94%. They had an average age of 27.0 ± 6.3 years and were of Fon ethnicity and related in 91.57% of cases. The majority were married (96.60%). The factors significantly associated with these closely spaced pregnancies were age between 25 and 30 years, household occupation, age at first birth, age at marriage, women’s perception of contraceptive method (CM), women’s knowledge of the existence of a center providing family planning services and non-use of MC. Conclusion: Close pregnancies are still very common in the commune of Abomey. It is therefore important to increase the use of contraceptive methods in this part of the country.

Formation of a Rapidly Rotating Classical Be-star in a Massive Close Binary System

This paper investigates the spin-up of a mass-accreting star in a close binary system passing through the first stage of mass exchange in the Hertzsprung gap. Inside an accreting star, angular momentum is carried by meridional circulation and shear turbulence. The circulation carries part of the angular momentum of the accreted layers to the accretor's surface. The greater the rate of arrival of angular momentum in the accretor is, the greater this part. It is assumed that this part of the angular momentum can be removed by the disk further from the accretor. If the angular momentum in the matter entering the accretor is more than half the Keplerian value, then the angular momentum obtained by the accretor during mass exchange stage does not depend on the rate of arrival of angular momentum. The accretor may have the characteristics of a Be-star immediately after the end of mass exchange.

Closed-Loop System Identification Approach of the Inertial Models

The mathematical model that approximates the dynamics of the industrial process is essential for the efficient synthesis of control algorithms in industrial applications. The model of the process can be obtained according to the identification procedures in the open-loop, or in the closed-loop. In the open-loop, the identification methods are well known and offer good process approximation, which is not valid for the closed-loop identification, when the system provides the feedback output and doesn’t permit it to be identified in the open-loop. This paper offers an approach for experimental identification in the closed-loop, which supposes the approximation of the process with inertial models, with or without time delay and astatism. The coefficients are calculated based on the values of the critical transfer coefficient and period of the underdamped response of the closed-loop system with P controller, when system achieves the limit of stability. Finally, the closed-loop identification was verified by the computer simulation and the obtained results demonstrated, that the identification procedure in the closed-loop offers good results in process of estimation of the model of the process.

Study on the Effect of Behavioral Interventions Based on the Theory of“Knowledge,Attitude,Practice”on Tuberculosis Cognitive Level of Close Contacts

Objective:Based on the theory of“Knowledge,Attitude,Practice,”health education was carried out for close contact with tuberculosis(TB)at a university in Beijing,and its impact on the students’awareness of TB was studied.This study could provide a reference for effective health education interventions among close contacts of TB in undergraduates.Methods:102 undergraduates who had close contact with one confirmed case of pulmonary TB in April 2021 at a university were randomly divided into a control group and an intervention group.The intervention group was given the“Knowledge,Attitude,Practice”health education intervention by professionally trained doctors,and were asked to complete a self-designed TB-related questionnaire before and after the intervention.Both groups performed the Tuberculin Skin Test(TST)and chest X-ray(CR)examination.Results:The rate of the TST test was 18.6%,and CR examination showed 0 cases of pulmonary TB.The survey results showed that the TB awareness rate(96.1%,49/51)in the intervention group was significantly higher than that of the control group(51.0%,26/51),and the differences in awareness rate between the two groups were statistically significant(P<0.05).Regarding the attitude/skills toward TB,the prevalence rate of tuberculosis-related attitude/behavior in the intervention group(94.1%,47/51)was significantly higher than that of the control group(60.8%,31/51),and the differences between the two groups were statistically significant(P<0.05).Conclusion:Both self-controlled and parallel-controlled studies showed that the health education intervention of“Knowledge,Attitude,Practice”improved the awareness of TB among close contacts of TB in undergraduates.

OPEN表和CLOSED表的合一

在人工智能传统的搜索方法中,一直是将OPEN表和CLOSED表分开的。这不仅增加了搜索算法的复杂性,久而久之,也许禁锢了人们的思想。文章试图改变这种状况,提出了一种与众不同的新思路,巧妙地将OPEN表和CLOSED表合二为一,减少了一些工作量,在一定程度上降低了算法的复杂性。