Numerical Simulation of Droplet Generation in Coaxial Microchannels

In this study,numerical simulations of the pinching-off phenomena displayed by the dispersed phase in a continuous phase have been conducted using COMSOL Multiphysics(level-set method).Four flow patterns,namely“drop flow”,“jet flow”,“squeeze flow”,and“co-flow”,have been obtained for different flow velocity ratios,channel diameter ratios,density ratios,viscosity ratios,and surface tension.The flow pattern map of two-phase flow in coaxial microchannels has been obtained accordingly,and the associated droplet generation process has been critically discussed considering the related frequency,diameter,and pinch-off length.In particular,it is shown that the larger the flow velocity ratio,the smaller the diameter of generated droplets and the shorter the pinch-off length.The pinch-off length of a droplet is influenced by the channel diameter ratio and density ratio.The changes in viscosity ratio have a negligible influence on the droplet generation pinching frequency.With an increase in surface tension,the frequency of generation and pinch-off length of droplets decrease,but for small surface tension the generation diameter of droplet increases.

Optimization and Construction of Collaborative Office under the Background of Smart Campus in Universities

At present, with the continuous development of technologies such as the Internet, big data, and artificial intelligence, smart campuses in universities are being rapidly constructed. Improving the informatization level of administrative management work is also an important content. The collaborative office work in multiple departments requires more standardized, convenient, intelligent, and secure office systems. In response to this issue, this article analyzes the optimization and construction process of collaborative office systems based on the development of university informatization, summarizes the operational results, and explores the prospects of smart office.

Decomposition Methods for Manufacturing System Scheduling:A Survey

Manufacturing is the application of labor, tools,machines, chemical and biological processing, to an original raw material by changing its physical and geometrical characteristics, in order to make finished products. Since the first industrial revolution, to accommodate the large-scale production,tremendous changes have happened to manufacturing through the innovations of technology, organization, management, transportation and communication. This work first reviews the highvolume low-mix process by focusing on the quantity production,transfer line and single model assembly line. Then, it reviews the high-volume high-mix process. For such a process type,mixed/multi model assembly line is usually adopted. Hence,two main decisions on them, i.e., balancing and, sequencing are reviewed. Thereafter, it discusses the low-volume high-mix process in detail. Then, technology gap and future work is discussed, and at last, conclusions are given.

Multiple Elite Individual Guided Piecewise Search-Based Differential Evolution

The differential evolution(DE)algorithm relies mainly on mutation strategy and control parameters'selection.To take full advantage of top elite individuals in terms of fitness and success rates,a new mutation operator is proposed.The control parameters such as scale factor and crossover rate are tuned based on their success rates recorded over past evolutionary stages.The proposed DE variant,MIDE,performs the evolution in a piecewise manner,i.e.,after every predefined evolutionary stages,MIDE adjusts its settings to enrich its diversity skills.The performance of the MIDE is validated on two different sets of benchmarks:CEC 2014 and CEC 2017(special sessions&competitions on real-parameter single objective optimization)using different performance measures.In the end,MIDE is also applied to solve constrained engineering problems.The efficiency and effectiveness of the MIDE are further confirmed by a set of experiments.

Resilient Event-Triggered Model Predictive Control for Adaptive Cruise Control Under Sensor Attacks

Dear Editor,This letter addresses the resilient model predictive control(MPC)problems for adaptive cruise control(ACC)systems under sensor attacks.In the light of vulnerabilities of ACC systems to sensor attacks,an intrusion detection mechanism is proposed at the controller side to distinguish abnormal data.Then,the robust control gains are derived to design the terminal region constraint for MPC.

Research on the Path of Digital Transformation of Postgraduate Education in Chinese Universities under the Background of Digital Education Strategy

Digital transformation of education is an important strategic content of information construction in Chinese universities in recent years. Postgraduate education is characterized by many types of postgraduates, complex training links, long training process, and obvious individuation. Its information construction and digital transformation are the difficulties in the construction of smart campus in colleges and universities. This paper discusses the current situation and main problems of postgraduate education informatization in colleges and universities, and puts forward the key points and suggestions of digital transformation of postgraduate education in colleges and universities from the aspects of optimizing the information platform of postgraduate education management and service, driving the modernization and wisdom of postgraduate education with data, constructing the integrated platform of intelligent teaching, and continuously improving the digital literacy of teachers and students.

Exploration on the Construction of University Logistics Information Service Platform

Logistics information construction in colleges and universities is an important part of smart campus. This paper expounds the current situation and existing problems of the logistics information construction in colleges and universities. Taking China University of Geosciences (Beijing) as an example, this paper discusses the construction principles and Personnel organization structure of the logistics information construction, and provides the construction scheme of the logistics information service platform. It can be used for reference for the implementation of logistics information construction in other colleges and universities.

抗苗勒氏管激素对绝经前早期乳腺癌患者化疗后卵巢功能的预测价值

目的:探讨血清标志物抗苗勒氏管激素(anti-Mullerian hormone,AMH)等对出现化疗诱导闭经的绝经前早期乳腺癌患者是否卵巢功能衰竭(ovarian failure,OVF)的预测价值,以优化辅助治疗策略及保护生育功能。方法:前瞻性分析2016年4月至2018年12月60例于广州医科大学附属第三医院行含环磷酰胺化疗方案的绝经前早期乳腺癌患者临床资料,监测化疗前后血清中的AMH、卵泡刺激素(follicle stimulating hormone,FSH)和雌二醇(estradiol,E2)水平变化。根据化疗结束后中位随访时间24个月时,E2、FSH是否维持在绝经后参考范围内,分为OVF组和卵巢功能恢复(ovarian recovery,OVR)组,分析对化疗后OVF的预测价值。结果:化疗前AMH预测化疗后24个月卵巢功能的曲线下面积(area under curve,AUC)为0.837(95%CI为0.719~0.920),年龄联合化疗前血清AMH等预测的AUC为0.924(95%CI为0.826~0.977)。化疗前的AMH≤1.05 ng/mL,1个疗程化疗后AMH≤0.56 ng/mL,化疗结束后3~6个月FSH>25.01 U/L及诊断年龄>37岁的阴性预测值均为100%。结论:血清AMH联合E2和FSH检测对鉴别绝经前早期乳腺癌患者化疗后是否OVF有重要价值,可将AMH纳入化疗前常规检测。

Recursive Approximation of Complex Behaviours With IoT-Data Imperfections

This paper presents an approach to recursively estimate the simplest linear model that approximates the time-varying local behaviors from imperfect(noisy and incomplete) measurements in the internet of things(IoT) based distributed decision-making problems. We first show that the problem of finding the lowest order model for a multi-input single-output system is a cardinality(l0) optimization problem, known to be NP-hard.To solve the problem a simpler approach is proposed which uses the recently developed atomic norm concept and the modified Frank-Wolfe(mFW) algorithm is introduced. Further, the paper computes the minimum data-rate required for computing the models with imperfect measurements. The proposed approach is illustrated on a building heating, ventilation, and air-conditioning(HVAC) control system that aims at optimizing energy consumption in commercial buildings using IoT devices in a distributed manner. The HVAC control application requires recursive thermal dynamical model updates due to frequently changing conditions and non-linear dynamics. We show that the method proposed in this paper can approximate such complex dynamics on single-board computers interfaced to sensors using unreliable communication channels. Real-time experiments on HVAC systems and simulation studies are used to illustrate the proposed method.

Polynomial Approach to Optimal One-wafer Cyclic Scheduling of Treelike Hybrid Multi-Cluster Tools via Petri Nets

A treelike hybrid multi-cluster tool is composed of both single-arm and dual-arm cluster tools with a treelike topology. Scheduling such a tool is challenging. For a hybrid treelike multi-cluster tool whose bottleneck individual tool is process-bound, this work aims at finding its optimal one-wafer cyclic schedule. It is modeled with Petri nets such that a onewafer cyclic schedule is parameterized as its robots' waiting time.Based on the model, this work proves the existence of its onewafer cyclic schedule that features with the ease of industrial implementation. Then, computationally efficient algorithms are proposed to find the minimal cycle time and optimal onewafer cyclic schedule. Multi-cluster tool examples are given to illustrate the proposed approach. The use of the found schedules enables industrial multi-cluster tools to operate with their highest productivity.

Liver protection strategies in liver transplantation

BACKGROUND： Liver transplantation is the therapy of choice for patients with end-stage liver diseases. However, the gap between the low availability of organs and high demand is continuously increasing. Innovative strategies for organ protection are necessary to expand donor pool and to achieve better outcomes for liver transplantation. The present review analyzed and compared various strategies of liver protection.DATA SOURCES： Databases such as PubM ed, Embase and Ovid were searched for the literature related to donor liver protection strategies using following key words： ＂ischemia reperfusion injury＂, ＂graft preservation＂, ＂liver transplantation＂, ＂machine perfusion＂ and ＂conditioning＂. Of the 146 studies identified,only those with cutting edge strategies were analyzed.RESULTS： A variety of therapeutic approaches were proposed to alleviate graft ischemia/reperfusion injury, which included static cold storage, machine perfusion （hypothermic, normothermic and subnormothermic）, manual conditioning （pre,post and remote）, and pharmacological conditioning. Evidences from animal experiments and clinical trials suggested that all these strategies could potentially protect liver graft; however, their clinical applications are limited partially due to their own disadvantages.CONCLUSIONS： There are a plenty of methods suggested to decrease the degree of donor liver transplantation-related injury. However, none of these approaches is perfect in clinical practice. More translational researches （molecular and clinical studies） are needed to improve the techniques in liver graft protection.

Study of human B7 homolog 1 expression in patients with hepatitis B virus infection

AIM: To further investigate the role of human B7 homolog 1 (B7-H1) in the mechanism of persistent hepatitis B virus (HBV) infection. METHODS: Peripheral and intra-hepatic B7-H1 expression were compared by flow cytometry and immunochemical staining between two 2 distinct groups, one being chronic HBV tolerance patients (CHB-T) and the other being acute hepatitis B patients (AHB). B7-H1 mRNA expression level was also compared by real time polymerase chain reaction between CHB-T and AHB patients. The location of intra-hepatic B7-H1 and CD40 expression were analyzed by immunofluorescence. The levels of B7-H1 and CD40 expression on cultured myeloid dendritic cells (mDCs) with or without hepatitis B surface antigen (HBsAg) treatment were analyzed dynamically by flow cytometry. Intracellular interferon-γ (IFN-γ) staining and the stimulatory capacity of mDC of cultured mDC with or without HBsAg treatment were also compared by flow cytometry. RESULTS: Peripheral B7-H1 expression on mDCs was increased significantly in AHB compared to CHB-T patients (P < 0.05). In the liver tissues from CHB-T patients, B7-H1 positive cells were almost absent despite a persistently elevated serum HBsAg load. In contrast, there were indeed increased B7-H1-positive cells in situ in the liver tissue from AHB. In vitro analysis showed the parallel upregulation of B7-H1 and CD40 on CD11c+ mDCs after the onset of stimulation. Addition of recombinant hepatitis B surface antigen (rHBsAg) significantly decreased CD40 expression (P < 0.05 at 16 h, 20 h and 24 h time points). B7-H1 expression was also inhibited by rHBsAg, and the inhibition rate of CD40 was greater than that of B7-H1. This preferential inhibition of CD40 expression on mDCs by rHBsAg resulted in the dysfunction of mDCs and T cells in the mixed leucocyte reaction (MLR) system. With rHBsAg pretreatment, in a carboxyfluorescein diacetate succinimidyl ester (CFSE) labeled MLR system at a ratio of 1:5 responder cell-stimulator cell (R/S), the CFSE dim percentage of T cells decreased from 85.1% to 25.4% and decreased from 30.3% to 12.0% at 1:10 R/S. IFN-γ production by CD8+ T cells, in the MLR system, was reduced significantly by HBsAg pretreatment. At ratios of 1:5 R/S, the percentage of IFN-γ and CD8 dual positive T cells decreased from 55.2% ± 5.3% to 15.1% ±3.1% (P < 0.001), and decreased from 35.0% ± 5.1% to 7.3% ± 2.7% at ratios of 1:10 R/S (P < 0.001). CONCLUSION: B7-H1 is not a signature of immune dysfunction, but an inflammation marker. HBsAg regulate immune response by tipping the balance between B7-H1 and CD40.

Temporal and Spatial Trends in HIV Positivity Rate for VCT Clinics—China,2015–2022

Introduction:Human immunodeficiency virus(HIV)voluntary counseling and testing(VCT)clinics play a critical role in identifying and diagnosing HIV cases.This study aimed to describe the trend of HIV positivity rate(HPR)among Chinese VCT clinics between 2015 and 2022.Methods:This study utilized data from the China Information System for Disease Control and Prevention to analyze the trend in the HPR for VCT clinics from 2015 to 2022.The HPR was calculated by dividing the number of newly-reported HIV cases by the number of HIV tests,multiplied by 100%.To identify temporal and spatial trends in the HPR,we employed joinpoint regression analysis and the Getis-Ord hotspot analysis.Results:From 2015 to 2022,VCT clinics in China performed a total of 22,075,386 HIV tests,leading to the identification of 260,353 HIV cases,resulting in a HPR of 1.18%.The HPR consistently declined over the study period,with an average annual percent change(AAPC)of−7.5%(95%confidence interval:−12.6%,−2.2%,P<0.05).The number of HPR hotspots also decreased from 41 in 2015 to 23 in 2022.These HPR hotspots were primarily located in Yunnan,Sichuan,Guangdong,and Guangxi provincial-level administrative divisions(PLADs).Among the 31 PLADs,16 showed a significant decrease in HPR during the study period(AAPC<0,PAAPC<0.05).Conclusions:VCT clinics in China have played a significant role in identifying HIV cases.The declining HPR observed in these clinics may indicates the progress has been made in some degree in mitigating HIV among high-risk populations.Therefore,it is crucial to further improving the utilization of VCT clinics for HIV testing.

Contributions of holography to the advancement of interferometric measurements of surface topography

Two major fields of study in optics—holography and interferometry—have developed at times independently and at other times together.The two methods share the principle of holistically recording as an intensity pattern the magnitude and phase distribution of a light wave,but they can differ significantly in how these recordings are formed and interpreted.Here we review seven specific developments,ranging from data acquisition to fundamental imaging theory in three dimensions,that illustrate the synergistic developments of holography and interferometry.A clear trend emerges,of increasing reliance of these two fields on a common trajectory of enhancements and improvements.

Physics-based virtual coherence scanning interferometer for surface measurement

Virtual instruments provide task-specific uncertainty evaluation in surface and dimensional metrology.We demonstrate the first virtual coherence scanning interferometer that can accurately predict the results from measurements of surfaces with complex topography using a specific real instrument.The virtual instrument is powered by physical models derived from first principles,including surface-scattering models,three-dimensional imaging theory,and error-generation models.By incorporating the influences of various error sources directly into the interferogram before reconstructing the surface,the virtual instrument works in the same manner as a real instrument.To enhance the fidelity of the virtual measurement,the experimentally determined three-dimensional transfer function of a specific instrument configuration is used to characterise the virtual instrument.Finally,we demonstrate the experimental validation of the virtual instrument,followed by virtual measurements and error predictions for several typical surfaces that are within the validity regime of the physical models.

Wave interaction for a generalized higher-dimensional Boussinesq equation describing the nonlinear Rossby waves

Based on an algebraically Rossby solitary waves evolution model,namely an extended(2+1)-dimensional Boussinesq equation,we firstly introduced a special transformation and utilized the Hirota method,which enable us to obtain multi-complexiton solutions and explore the interaction among the solutions.These wave functions are then employed to infer the influence of background flow on the propagation of Rossby waves,as well as the characteristics of propagation in multi-wave running processes.Additionally,we generated stereogram drawings and projection figures to visually represent these solutions.The dynamical behavior of these solutions is thoroughly examined through analytical and graphical analyses.Furthermore,we investigated the influence of the generalized beta effect and the Coriolis parameter on the evolution of Rossby waves.

我国典型城市群O_3污染成因和关键VOCs活性解析

京津冀、长三角、珠三角和成渝地区四大城市群在夏秋季大气臭氧(O_3)污染问题严重.为了深入认识O_3的区域污染特征及其成因,在上述4个城市群于2014~2016年夏秋季节,开展了大气O_3及其前体物(氮氧化物(NOx)、挥发性有机物(VOCs))等的综合观测研究.观测发现,臭氧污染区域性明显,臭氧最大8h值在59~146(10^(-9)V/V),整体上城市站点臭氧浓度水平较郊区站点低,臭氧前体物NO2平均浓度水平在4~22(10^(-9)V/V),VOCs浓度为11~53(10^(-9)V/V),VOCs活性水平在1.6~10.5s^(-1).使用基于观测的盒子模型(OBM)分析臭氧生成控制区,发现四大城市群的O_3生成多数处于人为源VOCs控制区或者过渡区,且对烯烃和芳香烃的敏感性最强.运用PMF受体模型对城市站点VOCs来源进行解析,结果表明机动车尾气排放和汽油挥发是城市VOCs主要来源,占比30%~50%;溶剂涂料使用其次,占比为10%~20%.综合而言,我国现阶段臭氧污染防控应以VOCs控制为主,其中应着重控制机动车尾气排放和溶剂涂料使用.

Explicit diagnosis of the local ozone production rate and the ozone-NOx-VOC sensitivities

In the troposphere, ozone is a harmful gas compound to both human health and vegetation. Ozone is produced from the reaction of NO_x(@NO + NO_2) and VOCs(volatile organic compounds) with light. Due to the highly nonlinear relationships between ozone and its precursors, proper ozone mitigation relies on the knowledge of chemical mechanisms. In this study, an observation-based method is used to simulate ozone formation and elucidate its controlling factors for a rural site on the North China Plain. The instantaneous ozone production rate is calculated utilizing a box model using the dataset obtained from the Wangdu campaign. First, the model was operated in a time-dependent mode to calculate the ozone production rate at each time stamp. The calculated ozone formation rate showed a diurnal average maximum value of 17 ppbv/h(1-h diurnal averaged). The contribution of individual peroxy radicals to ozone production was analyzed. In addition, the functional dependence of calculated P(O_3) reveals that ozone production was in a NO_x-limited regime during the campaign. Furthermore, the missing peroxy radical source will further extend NO_x-limited conditions to earlier in the day, making NO_xlimitation dominate more of a day than the current chemical model predicts. Finally, a multiple scenarios mode,also known as EKMA(empirical kinetic modeling approach), was used to simulate the response of P(O_3) to the imaginary change in precursor concentrations. We found that ozone production was in the NO_x-limited region. However, the use of NO_2 measured by the molybdenum converter and/or the absence of a peroxy radical source in the current chemical model could over-emphasize the VOC-limited effect on ozone production.

The D253N Mutation in the Polymerase Basic 2 Gene in Avian Influenza(H9N2) Virus Contributes to the Pathogenesis of the Virus in Mammalian Hosts

Mutations in the polymerase basic 2(PB2) gene of avian influenza viruses are important signatures for their adaptation to mammalian hosts. Various adaptive mutations have been identified around the 627 and nuclear localization sequence(NLS) domains of PB2 protein, and these mutations contribute to the replicative ability of avian influenza viruses.However, few studies have focused on adaptive mutations in other regions of PB2. In this study, we investigated the functional roles of the D253N mutation in PB2 in an H9N2 virus. This mutation was found to affect an amino acid residue in the middle domain of the PB2 protein. The virus with the D253N mutation showed higher polymerase activity and transiently increased viral replication in human cells. However, the mutant did not show significant differences in viral replication in the respiratory tract of mice upon infection. Our results supported that the D253N mutation in the middle domain of PB2, similar to mutations at the 627 and NLS domains, specifically contributed to the replication of avian influenza viruses in human cells.

Mechanism of photon-induced performance changes in silicon heterojunction solar cells

Short-wavelength ultraviolet(UV)photons adversely affect hydrogenated amorphous silicon thin films,as well as on silicon heterojunction(SHJ)solar cells and modules.This research examines the impact and mechanisms of photon-induced performance changes.UV A exposure disrupts Si-H bonds,significantly reducing hydrogen content in both intrinsic and doped hydrogenated amorphous silicon(a-Si:H)films.This disruption impairs the interface passivation effect,leading to the degradation of SHJ solar cells and modules,primarily indicated by a decrease in open-circuit voltage(V_(oc))and fill factor(FF).UV irradiation from the front side of SHJ solar cells reduces V_(oc)and FF by 1.38%and 2.28%,respectively,resulting in a 2.28%efficiency decline.Cells irradiated from the backside show decreases in V_(oc)and FF of approximately 1.96%and 2.73%,respectively,leading to an overall efficiency reduction of approximately 3.58%.However,subsequent light-soaking increases V_(oc)and FF by approximately 0.96%and 1.37%,respectively,for frontside-irradiated cells,achieving an overall efficiency improvement of approximately 2.51%.Thus,light-soaking effectively recovers performance losses caused by UV irradiation in SHJ solar cells.This research clarifies the mechanisms influencing the performance of a-Si:H thin films,SHJ solar cells,and modules under UV irradiation and light-soaking,offering significant contributions towards the development of highly efficient and reliable SHJ devices.