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Premixed flames of ammonia/hydrogen/air mixtures were investigated in a combustor capable of creating an isotropic and homogeneous turbulent field. Based on the propagation characteristics under different hydrogen ratios, turbulence intensities, and pressures with Lewis numbers of about 1, the effects of flame chemistry, turbulent stretch, and pressure on the turbulent burning velocity were analyzed. The results show that turbulence intensity can significantly enhance the flame propagation, while the effect of pressure varies under different turbulence conditions and the hydrogen ratio corresponds to the enhancement of the flame chemistry, which has a great influence on the flame propagation. The increase of pressure and turbulence intensity makes the flame have a larger Karlovitz number and thus susceptible to turbulent stretching. In addition, the turbulent flame shows obvious self-similar accelerated propagation, but there is a deviation in the fitting index when the hydrogen ratio is larger. In addition, considering the effect of pressure on the combustion process, this paper studies the applicability of several correlations for turbulent burning velocity under high pressure and introduces the normalized pressure and turbulence integral length scales into these correlations for in-depth analysis and then further discusses the limitations of the existing correlations.

In the foreseeable future, the use of fossil energy is still irreplaceable, makes efficient use of fossil energy and reduce emissions became important topics. Diesel engines have a very high share in the transportation field, and high-pressure common rail system has highly improved the performance of diesel engines. As the most important component of common rail system, the performance of common rail injector directly affects the engine. Precision coupling components are composed of moving parts with very precise clearance fit in the injector. With the wear of parts, fuel leakage of precision coupling components may reach the same level as injection quantity, which will seriously affect the injection pressure actually established, and then affect the power, efficiency, and emission performance of diesel engine. Many researchers have studied fuel leakage of precision coupling components, and put forward different methods to reduce fuel leakage, including improving the machining accuracy and machining annular grooves on parts. However, the wear of parts makes it a high-cost and low-effective method to improve machining accuracy. Besides, researchers have not fully considered the deformation of parts. In this work, fluid-solid coupling simulations were performed to analyze deformation and static fuel leakage characteristics, and to investigate effects of pressure equalizing structure on deformation and leakage of precision coupling component in common-rail injector. Different from the previous researches, the influence of machining the annular groove on the plunger sleeve instead of on the plunger, and influence of coexistence of annular groove and deformation were considered. The results show the deformation characteristics of the parts, the fuel flow characteristics in the gap, and the influence of the annular groove on the fuel leakage. The connection between the deformation of parts and fuel leakage, and potential methods to reduce the leakage are also discussed.

Pressure fluctuations in the high-pressure common rail systems have a significant impact on the fuel injection and engine performance. In this study, the pressure fluctuation in a high-pressure common rail system was investigated using simulations. The fluctuation can be caused by hydraulic structures and control factors. The degree of influence of those two causes was evaluated and discussed in this work. First, the hydraulic and control factors that dominate the models of injection systems were established. Then, the mechanism of pressure fluctuation on high-pressure common rail systems was highlighted. A dimensionless parameter was defined to quantitatively describe the effects of control factors and hydraulic structures on pressure fluctuation. Finally, the developed model was used to study the effects of injection conditions and structural parameters on pressure fluctuation. The results show that the injection frequency has a limited effect on the system pressure fluctuation. In addition, the increase in the injection energizing time and the injection pressure will increase the hydraulic pressure fluctuations of the system, thus increasing the total pressure fluctuations of the system. Moreover, the increase in the volume by increasing the diameter was found to decrease the pressure fluctuations more effectively compared to the impact of the length, but there is a marginal diminishing effect. The results demonstrated that the effect of a 20 bar signal error and a 160 mm common rail length is almost the same on decreasing pressure fluctuations. It can be concluded that the improvements in the electronic part of the high-pressure common rail system have more potential than the mechanical part.

ABSTRACTPosition-dependent disturbances have a significant impact on the low-speed positional motions of a permanent magnet synchronous motor (PMSM) driven servomechanism; therefore, this study has aimed to develop a control and compensation design, based on the proportional-integral-proportional (PIP) feedback control extensively used in commercialized PMSM drivers, for improving the low-speed positional motions of the PMSM-driven servomechanism without excessively increasing the computational burden on commercialized PMSM drivers and without hardware modifications to commercialized PMSM servomotor packs. The angular position and driving torque signals of the PMSM in low-speed motions were used for a spatial fast Fourier transform analysis to build the position-dependent disturbance model and determine the dominant positional frequencies. Then, a low-speed positional motion control and compensation design was developed that integrates the dynamic compensation, friction compensation, and position-dependent disturbance compensation approaches for the PMSM-driven servomechanism to improve its low-speed positional motion performance. The positional motion experiments performed on a PMSM test bench demonstrated that, in comparison with the PIP feedback control extensively used in commercialized PMSM drivers, the PIP control and compensation designed in this study improved the position and speed responses and suppressed the position and speed fluctuation phenomenon of the PMSM-driven servomechanism during low-speed motions.

C28H32Fe2N4O13, monoclinic, P2/n(no. 13), a= 8.0964(3) Å, b= 13.4889(5) Å, c= 14.0543(5) Å, β= 95.190(3)°, V= 1528.60(10) Å3, Z= 2, Rgt(F) = 0.0405, wRref(F2) = 0.0972, T= 173(2) K.

C36H44FeN10O8S2, monoclinic, P21/c(no. 14), a= 8.7712(5) Å, b= 24.6087(12) Å, c= 9.6083(4) Å, β= 96.952(5)°, V= 2058.68(18) Å3, Z= 2, Rgt(F) = 0.0664, wRref(F2) = 0.1318, T= 173(2) K.

To achieve security and privacy for data stored on the cloud, we need the ability to secure data in compute. Equality comparisons, “$x=y, x\ne y$x=y,x≠y”, have been widely studied with many proposals but there is much room for improvement for order comparisons, “$x < y,~x \leq y,~x > y \text{ and } x \geq y$x<y,x≤y,x>yandx≥y”. Most protocols for order comparisons have some limitation, either leaking some information about the data or requiring several rounds of communication between client and server. In addition, little work has been done on retrieving with compound conditions, mixing several equality and order comparisons. Fully homomorphic encryption (FHE) promises the ability to compute arbitrary functions on encrypted data without sacrificing privacy and without communication, but its potential has yet to be fulfilled. Particularly, private comparisons for database queries using FHE are expensive to compute. In this article, we design an efficient private database query (PDQ) protocol which supports compound conditions with equality and order comparisons. To this end, we first present a private comparison algorithm on encrypted integers using FHE, which scales efficiently for the length of input integers, by applying techniques from finite field theory. Then, we consider a scenario for PDQ protocols, querying for values based on a conjunction of one order and four equality conditions on key columns. The proposed algorithm and protocol are implemented and tested to determine their performance in practice. The proposed comparison algorithm takes about $25.259$25.259 seconds to compare 697 pairs of 64-bit integers using Brakerski-Gentry-Vaikuntanathan's leveled FHE scheme with single instruction multiple data (SIMD) techniques at more than 138 bits of security. This yields an amortized rate of just 36 milliseconds per comparison. On top of that, we show that our techniques achieve an efficient PDQ protocol for one order and four equality comparisons, achieving an amortized time and communication cost of 57 milliseconds and 448 bytes per database element.

Chronic cerebral hypoperfusion is associated with vascular dementia (VaD). Cerebral hypoperfusion may initiate complex molecular and cellular inflammatory pathways that contribute to long-term cognitive impairment and memory loss. Here we used a bilateral common carotid artery stenosis (BCAS) mouse model of VaD to investigate its effect on the innate immune response—particularly the inflammasome signaling pathway. Comprehensive analyses revealed that chronic cerebral hypoperfusion induces a complex temporal expression and activation of inflammasome components and their downstream products (IL-1β and IL-18) in different brain regions, and promotes activation of apoptotic and pyroptotic cell death pathways. Polarized glial-cell activation, white-matter lesion formation and hippocampal neuronal loss also occurred in a spatiotemporal manner. Moreover, in AIM2 knockout mice we observed attenuated inflammasome-mediated production of proinflammatory cytokines, apoptosis, and pyroptosis, as well as resistance to chronic microglial activation, myelin breakdown, hippocampal neuronal loss, and behavioral and cognitive deficits following BCAS. Hence, we have demonstrated that activation of the AIM2 inflammasome substantially contributes to the pathophysiology of chronic cerebral hypoperfusion-induced brain injury and may therefore represent a promising therapeutic target for attenuating cognitive impairment in VaD.

The finite difference method is widely used in seismic wave numerical simulation, reverse time migration and full waveform inversion. However, the numerical dispersion problem seriously affects the results of seismic imaging and inversion. Based on this, we introduced cosine-combined window function (CCWF) used in harmonic analysis of the power system and compared the amplitude response and error properties with other window functions. Then, an optimised CCWF and a new weighting method are proposed, which results in finite-difference operators with not only large spectral coverage but also small precision error fluctuation. In this paper, the analysis shows the good stability of using finite difference operators. Finally, we perform numerical forward modelling, which denotes that our method is superior than other optimum methods. From an economic point of view, this method will effectively reduce the computation cost and improve efficiency.

To investigate the effect of the flame inherent instabilities and turbulence on the flame structural characteristics, premixed combustion experiments of 50% H2/50% CO at a equivalence ratio of 0.6 were conducted in a turbulent combustion bomb in atmospheric temperature and pressure. The correlation degree was defined to study the correlation relation between flame structural characteristics at different moments, and the wavelet transform was used to investigate the detail components at different scales. The results indicate that, with the development of the flame, the cellular structure was enhanced and the correlation degree gradually decreased. The fluctuations of the detail components at the larger scale were stronger and included more energy, which corresponded to the main factor causing the flame front complex. With the turbulence intensity increase, the root mean square amplitude and energy of the detail components increased, leading to the increase of the interaction of different disturbances, while the correlation degree of the flame decreased. The correlation degree of the detail components presented a staggered distribution of higher and lower values, which indicated the complex changes of the disturbances at different scales.

As a kind of fuel with low‐carbon emissions, hydrogen‐rich syngas has a large resource potential and is a promising alternative energy resource. A series of experiments in a constant volume combustion bomb are carried out to investigate the effects of turbulence and diffusional–thermal (DT) instability on a hydrogen‐rich syngas turbulent premixed flame. The flow field in the constant volume combustion bomb is calibrated, and the turbulent flow field's homogeneity and isotropy were investigated. The effects of different speeds of fan (1366–4273 rpm), hydrogen fractions (55%–95%), pressures (1.0–3.0 bar), and equivalence ratios (0.6–1.0) on the hydrogen‐rich syngas turbulent premixed flame are studied. According to the analyses, the flow field in the experimental device exhibits good homogeneous and isotropic characteristics. With the increase of turbulence intensity, equivalence ratio, hydrogen fraction, or pressure, the turbulent flame propagation speed increases gradually. As the hydrogen fraction increases or the equivalence ratio decreases, the effective Lewis number decreases, and the effect of DT instability on the flame increases. The research in this article is crucial for the clean and efficient utilization of hydrogen‐rich syngas and the design of related burners. In this work, a stable and uniform isotropic turbulent flow field is established. The flame evolution and propagation speed of hydrogen‐rich syngas are evaluated. The influence of turbulence intensity, equivalence ratios, pressures, and hydrogen fractions on flame propagation characteristics are studied and the influence of diffusional–thermal instability on flame propagation speed is analyzed.

To investigate the self-similar propagation of a turbulent expanding flame, H2/CO/air mixtures, with vas hydrogen fractions (10, 30, and 50%) and equivalence ratios (0.6–1.0) were ignited in a turbulent combustion bomb under various turbulence intensities. The turbulent flame Reynolds number was used to analyze its dynamic propagation characteristics. The results showed that the growth rate of the flame propagation speed gradually decreased when the flame developed to a certain degree. As the equivalence ratio or hydrogen fraction increased, the dimensionless turbulent flame propagation speed decreased, as did its exponential dependence on the turbulent flame Reynolds number. There was a linear relationship between ST/Sland ReT,f0.5, and a decrease in Madue to increase in the hydrogen fraction and decrease in equivalence ratio had completely opposite effects on the self-similar propagation of the syngas/air turbulent premixed flame.

Fully homomorphic encryption (FHE) brings a paradigm shift in cryptographic engineering by enabling us to resolve various unsolved problems. Among them, this work solves the problem to design a private database query (PDQ) protocol that supports compound queries with wildcard conditions on encrypted databases using FHE. More precisely, we consider a setting where clients outsource an encrypted database using FHE to a remote server, and later request results of compound queries including a wildcard search condition–given a set of attribute values $\lbrace A_1, A_2, \ldots, A_{n}\rbrace${A1,A2,...,An} and a search pattern $W$W, retrieve a set of all attribute values $A_i$Ai's in which the pattern $W$W occurs. To this end, we first develop an algorithm for testing whether an encrypted string contains an encrypted pattern without revealing any information of the pattern, taking auxiliary encryptions as additional inputs. Then, using this algorithm, we design PDQ protocols on encrypted databases, which support compound queries using wildcard search conditions. Finally, we demonstrate proof-of-concept implementation results of our protocols by exploiting single-instruction-multiple-data operations and multi-threading techniques.

ABSTRACTIncreasing significance has been ascribed to student engagement, as a measure of success of both teachers and programs. However, since users of the term commonly tend not to explain, rationalise or problematise their understanding of engagement, its value to understand or transform learning may be limited. While clarification has occurred in conceptual work, there is a lack of empirical work that extends beyond understandings of engagement-as-behaviour, as well as insufficient work exploring what students understand engagement to be. Further, much work on engagement is rooted in physical campuses and face-to-face delivery, which represents an incomplete picture of how students actually engage in study. This article investigates student perceptions of engagement in two blended learning Initial Teacher Education programs. It offers a critical discussion of how research can be re-considered in light of changing learning contexts and changing understandings of ways to investigate engagement. The findings of this study support previous work that found multiple levels and meanings of student engagement exist. New complex and multidimensional models of engagement are proposed, which can open new possibilities for designing studies and analysing findings. This article argues that including and questioning physical, virtual and political contexts and power, affect, relationships, linearity and essential measurability are important features of new models of engagement.

With the rapid development of immunology, molecular biology, and associated technologies such as next-generation sequencing, cellular immunotherapy has recently become the fourth major cancer treatment. Immunotherapies based on T cells, natural killer cells, and dendritic cells play key roles in cancer immunotherapy. However, their application in clinical practice raises several ethical issues. Thus, studies should focus on proper adherence to basic ethical principles that can effectively guide and solve related clinical problems in the course of treatment, improve treatment effects, and protect the rights and interests of patients. In this review, we discuss cellular immunotherapy-related ethical issues and highlight the ethical practices and current status of cellular immunotherapy in China. These considerations may supplement existing ethical standards in cancer immunotherapy. 本文旨在对细胞免疫治疗相关的伦理学问题进行 探讨,并通过分析我国细胞免疫治疗相关伦理学 实践及现状,为规范我国肿瘤细胞免疫治疗的伦 理标准提供参考。随着免疫学、分子生物学等学 科的飞速发展和高通量测序等技术的普及,肿瘤 免疫治疗已成为第四大肿瘤治疗方法。肿瘤细胞 免疫治疗,如各种基于T 细胞、自然杀伤(NK) 细胞和树突状细胞(DC)的免疫治疗在其中发挥 了重要作用。随着临床实践的开展,一些相关的 伦理学问题逐渐暴露出来。如何在治疗过程中坚 持基本伦理原则,有效指导并解决相关临床问 题,提高治疗效果,保护受试者权益,是目前亟 需研究的重要课题。本文对与之相关的伦理学问 题进行探讨,并通过分析我国细胞免疫治疗相关 伦理学实践及现状,以期为规范我国肿瘤细胞免 疫治疗的伦理标准提供参考。

Although the clinical application of new drugs has been shown to be effective in slowing disease progression and improving the quality of life in patients with pulmonary fibrosis, the damaged lung tissue does not recover with these drugs. Thus, there is an urgent need to establish regenerative therapy, such as stem cell therapy or tissue engineering. Moreover, the clinical application of mesenchymal stem cell (MSC) therapy has been shown to be safe in humans with idiopathic pulmonary fibrosis (IPF). It seems that a combination of MSC transplantation and pharmaceutical therapy might have additional benefits; however, the experimental design for its efficacy is still lacking. In this review, we provide an overview of the mechanisms that were identified when IPF was treated with MSC transplantation or new drugs. To maximize the therapeutic effect, we suggest that MSC transplantation is combined with drug application for synergistic effects. This review provides clinicians and scientists with the most efficient medical options, in the hope that this will spur on future research and lead to an eventual cure for this disease.

To investigate the flame propagation characteristics and flame structural characteristics, experimental and numerical methods have been used to study the propane/air mixtures with the equivalence ratio ranging from 0.9 to 1.3 under various initial pressures. The core elemental reactions and active radicals, which had a significant effect on the laminar burning velocity, were analyzed and confirmed. In addition, the influence of flame inherent instabilities on the flame structural characteristics was quantitatively studied by extracting the crack information. The results indicated that the laminar burning velocity increased first and then decreased with the increase in equivalence ratio. As the initial pressure increased, the laminar burning velocity decreased. The laminar burning velocity showed the highest sensitivity to the chain branching reaction of H + O2= O + OH. As the equivalence ratio increased, the main chain inhibiting reaction changed from H + O2+ H2O ⇔ HO2+ H2O to CH3+ H (+M) = CH4(+M). As the equivalence ratio increased, the hydrodynamic instability increased first and then decreased. Meanwhile, the thermal-diffusive instability increased significantly, and the flame became more unstable as a whole, while crack length under the same radius increased significantly. With the increase in initial pressure, the hydrodynamic instability was enhanced, and crack length increased.

Stricture formation at the bilioenteric anastomosis is a rare but important postoperative complication. However, information on this complication is lacking in the literature. In the present study, we aimed to assess its prevalence and predictive factors, and report our experience in managing bilioenteric anastomotic strictures over a ten-year period.

To investigate the antidepressant mechanism of acupuncture at the molecular level in the pituitary gland of rats exposed to chronic restraint stress (CRS).

[EAPy][PF6] Pyridinium ionic liquid was synthesized by two-step process: introduction of one ethyl acetate group and anions metathesis. Additionally, single crystals of the IL was first obtained by solvent-evaporation method in growth systems. [EAPy][PF6] crystallizes in the monoclinic space group C2/c, with unit cell parameters a =22.748 Å, b =6.204 Å, c =18.552 Å, β =92.66°, z =8,V=2615(3) Å, Dc =1.58 Mg/m3 and F(000)=1264. In its supramolecular structure, the double zigzag chains are formed by hydrogen bonds and these [P(1)F6]- and [P(2)F6]- anions are sandwiched respectively by pyridinium rings and ethyl acetate groups in the packing pattern. Moreover, [EAPy][PF6] exhibits relatively high thermal stability and obvious supercooling during the cooling process, which makes pyridinium IL difficult to crystallize.