Numerical study on the cavity dynamics for vertical water entries of twin spheres

In this study, a three dimensional(3D) numerical model of six-degrees-of-freedom(6DOF) is applied to simulate the water entries of twin spheres side-by-side at different lateral distances and time intervals.The turbulence structure is described using the shear-stress transport k-ω(SST k-ω) model, and the volume of fluid(VOF) method is used to track the complex air-liquid interface. The motion of spheres during water entry is simulated using an independent overset grid. The numerical model is verified by comparing the cavity evolution results from simulations and experiments. Numerical results reveal that the time interval between the twin water entries evidently affects cavity expansion and contraction behaviors in the radial direction. However, this influence is significantly weakened by increasing the lateral distance between the two spheres. In synchronous water entries, pressure is reduced on the midline of two cavities during surface closure, which is directly related to the cavity volume. The evolution of vortexes inside the two cavities is analyzed using a velocity vector field, which is affected by the lateral distance and time interval of water entries.

Deformation mechanism and roof pre-splitting control technology of gob-side entry in thick hard main roof full-mechanized longwall caving panel

This paper explores the deformation mechanism and control technology of roof pre-splitting for gob-side entries in hard roof full-mechanized longwall caving panel(LTCC).The investigation utilizes a comprehensive approach that integrates field monitoring,theoretical analysis,and numerical simulation.Theoretical analysis has illuminated the influence of the length of the lateral cantilever beam of the main roof(LCBM)above the roadway on the stability of the gob-side entry behind the panel.Numerical simulations have further revealed that the longer LCBM results in heightened vertical stress within the coal pillar,developed cracks around the roadway,and more pronounced damage to the roadway.Moreover,numerical simulations also demonstrate the potential of roof pre-splitting technology in optimizing the fracture position of the hard roof.This technology significantly reduces the length of the LCBM,thereby alleviating stress concentration in the coal pillars and integrated coal rib while minimizing the destruction of the gob-side entry.Therefore,this manuscript first proposes the use of roof pre-splitting technology to control roadway deformation,and automatically retain the entry within a hard roof LTCC panel.Field implementation has demonstrated that the proposed automatically retained entry by roof pre-splitting technology effectively reduces gob-side entry deformation and achieves automatically retained entry.

Roles of host proteases in the entry of SARS-CoV-2

The spike protein(S)of SARS-CoV-2 is responsible for viral attachment and entry,thus a major factor for host suscep-tibility,tissue tropism,virulence and pathogenicity.The S is divided with S1 and S2 region,and the S1 contains the receptor-binding domain(RBD),while the S2 contains the hydrophobic fusion domain for the entry into the host cell.Numerous host proteases have been implicated in the activation of SARS-CoV-2 S through various c leavage sites.In this article,we review host proteases including furin,trypsin,transmembrane protease serine 2(TMPRSS2)and cathepsins in the activation of SARS-CoV-2 S.Many betacoronaviruses including SARS-CoV-2 have polybasic residues at the S1/S2 site which is subjected to the cleavage by furin.The S1/S2 cleavage facilitates more assessable RBD to the receptor ACE2,and the binding triggers further conformational changes and exposure of the S2'site to proteases such as type Il transmembrane serine proteases(TTPRs)including TMPRSS2.In the presence of TMPRSS2 on the target cells,SARS-CoV-2 can utilize a direct entry route by fusion of the viral envelope to the cellular membrane.In the absence of TMPRSS2,SARS-CoV-2 enter target cells via endosomes where multiple cathepsins cleave the S for the successful entry.Additional host proteases involved in the cleavage of the S were discussed.This article also includes roles of 3C-like protease inhibitors which have inhibitory activity against cathepsin L in the entry of SARS-CoV-2,and discussed the dual roles of such inhibitors in virus replication.

Polypyrimidine Tract-Binding Protein Enhances Zika Virus Translation by Binding to the 5'UTR of Internal Ribosomal Entry Site

Objectives To identify the 5'untranslated region of Zika virus(ZIKV 5'UTR)RNA-binding proteins and to investigate the impact of the binding protein on the activity of internal ribosomal entry site(IRES)located in ZIKV 5'UTR and virus production.Methods Interacting proteins in U251 cells were captured using tRSA-tagged ZIKV 5'UTR RNA and tRSA-ZIKV 5'UTR RNA-binding proteins were visualized by SDS-PAGE silver staining,Subsequently,liquid chromatographytandem mass spectrometry(LC-MS/MS),bioinformatics analysis,and Western blot were used to identify the candidate proteins binding to ZIKV 5'UTR.Dicistronic expression assay and plaque forming assay were performed to analyze the effect of the binding protein on ZIKV IRES activity and ZIKV production,respecitvely.Results tRSA RNA pull-down assay,LC-MS/MS,and Western blot analysis showed that polypyrimidine tractbinding protein(PTB)bound to the ZIKV 5'UTR.Furthermore,dual luciferase reporter assay revealed that overexpression of PTB significantly enhanced the IRES activity of ZIKV(t=10.220,P<0.001),while PTB knockdown had the opposite effect(t=4.897,P<0.01).Additionally,virus plaque forming assay demonstrated that up-regulation of PTB expression significantly enhanced viral titer(t=6.400,P<0.01),whereas reducing PTB expression level weakened virus infectivity(t=5.055,P<0.01).Conclusion PTB positively interacts with the ZIKV 5'UTR and enhances IRES activity and virus production.

Ground response and failure mechanism of gob-side entry by roof cutting with hard main roof

This study is the result of long-term efforts of the authors’team to assess ground response of gob-side entry by roof cutting(GSERC)with hard main roof,aiming at scientific control for GSERC deformation.A comprehensive field measurement program was conducted to determine entry deformation,roof fracture zone,and anchor bolt(cable)loading.The results indicate that GSERC deformation presents asymmetric characteristics.The maximum convergence near roof cutting side is 458 mm during the primary use process and 1120 mm during the secondary reuse process.The entry deformation is closely associated with the primary development stage,primary use stage,and secondary reuse stage.The key block movement of roof cutting structure,a complex stress environment,and a mismatch in the supporting design scheme are the failure mechanism of GSERC.A controlling ideology for mining states,including regional and stage divisions,was proposed.Both dynamic and permanent support schemes have been implemented in the field.Engineering practice results indicate that the new support scheme can efficiently ensure long-term entry safety and could be a reliable approach for other engineering practices.

Application of Thermodynamic Database to Corrosion of ZrO_(2) Containing Submerged Entry Nozzle in Steel Continuous Casting Process

The CALPHAD thermodynamic databases are very useful to analyze the complex chemical reactions happening in high temperature material process.The FactSage thermodynamic database can be used to calculate complex phase diagrams and equilibrium phases involving refractories in industrial process.In this study,the FactSage thermodynamic database relevant to ZrO_(2)-based refractories was reviewed and the application of the database to understanding the corrosion of continuous casting nozzle refractories in steelmaking was presented.

Epidata Entry-Epidata Analysis软件联用在医院处方分析评价中的应用

目的探讨不合格处方分析评价的新技术、新方法。方法运用Epidata Entry软件进行数据录入,通过编写check文件,对录入数据和流程进行控制,联用Epidata Analysis软件对不合格处方进行分析。结果 Epidata Entry软件便于不合格处方的录入和管理,Epidata Analysis软件便于不合格处方的分析,两软件联用可实现不合格处方数字化管理,方法可靠。结论该方法应用于医院处方分析评价,具有简单、易学、方便、实用、几乎不需任何费用等优点。

Comparison and Analysis on Animal and Plant Quarantine of Entry Mails among China, Australia and New Zealand

With the significant increase of the number of entry mails in China, mail inspection has become more and more challenge. Australia and New Zealand are the two countries recognized as the ones with the most stringent inspection and quarantine measures in the world. The mail inspection work in China, Australia and New Zealand was compared on the aspects of mail quarantine system, inspection, quarantine treatment and punishment, based on which something worth learning and referring could be found and some suggestions were put forward, with the aim to provide theoretical basis for the animal and plant quarantine of entry mails.

小煤柱沿空掘进瓦斯综合防治技术研究

以某矿31018回风顺槽小煤柱沿空掘进为工程背景,对采空区侧煤体卸压范围考察,确定采空区侧煤体卸压范围,并在卸压范围进行残余瓦斯含量测试,划定无突出危险性范围;采用对小煤柱进行注浆加固和巷道全断面喷浆措施防止采空区瓦斯溢出;使用钻屑指标法对掘进工作面进行预测和验证。统计表明:31018回风顺槽小煤柱沿空掘巷过程中,预测指标K_(1max)=0.24,S_(max)=3.4,平均进尺5.8 m/d,回风流平均瓦斯浓度为0.15%,单日绝对瓦斯涌出量平均为1.04 m^(3)/min,实现了巷道安全掘进。

Clogging behavior of submerged entry nozzles for Ti-bearing IF steel

The nozzle clogging behavior of Ti-bearing IF steel was studied by metallographic analysis,scanning electron microscopy（SEM）, energy dispersive spectroscopy（EDS）,and X-ray diffraction（XRD）.According to the experimental results,nozzle clogging primarily appears three layers.There are a lot of large-sized iron particles in the inner layer and mainly slag phase in the middle and outer layers.The principal clog constituents of the inner layer are loose alumina cluster inclusions and granular shaped alumina inclusions,containing iron particles. The clog constituents of the middle layer are mainly dendrite alumina inclusions.The primary phases existing in nozzle clogging are FeO·TiO2 and FeO·Al2O3 besidesα-Al2O3 and a-Fe.The FeO·TiO2 phases among the deposits adhere the deposits together firmly enough to lead to the inferior castability of Ti-bearing ultra low carbon steel compared with that of Ti-free low carbon Al-killed steel.

厚朴温中汤煎汤与其配方颗粒化学成分及入血成分一致性研究

目的研究厚朴温中汤煎汤与其配方颗粒两者的化学成分及入血成分的一致性,探讨配方颗粒替用传统汤剂的适用性。方法采用猪油与冷食醋制造脾胃虚寒大鼠模型,通过ELISA试剂盒测试各给药组生化指标以评价药效。采用超高效液相色谱-四极杆-飞行时间串联质谱(UPLC-Q-TOF-MS/MS)技术研究厚朴温中汤煎汤与其配方颗粒的化学成分、入血原型成分与代谢物。根据保留时间、精确相对分子质量、二级质谱裂解碎片及对照品进行成分鉴定和表征。结合PeakView、MakerView、MetabolitePilot等软件进行模式识别评价厚朴温中汤煎汤与其配方颗粒化学成分及入血成分的一致性。结果以有监督的正交偏最小二乘法(OPLS-DA),设置VIP>2.5,筛选出两者差异性化学成分66个,差异性入血原型成分14个,差异性入血代谢物12个。结论从生化指标来看,厚朴温中汤煎汤与其配方颗粒无显著性差异。从化学成分来看,橙皮苷、山姜素等黄酮类及木脂素类成分差异较大,入血后,煎汤与其配方颗粒入血成分差异缩小,特别是橙皮苷、山姜素等黄酮类成分的差异明显缩小,成分入血后似乎发生了“拉平效应”。

Rock burst mechanism analysis in an advanced segment of gob-side entry under different dip angles of the seam and prevention technology

In order to investigate the frequent occurrences of rock burst in gob-side entry during the mining process of the mining zone No. 7, the mechanical model of main roof of fully-mechanized caving mining before breaking was established by the Winkler foundation beam theory, and the stress evolution law of surrounding rock with different dip angles of the seam during the mining process was analyzed by using FLAC3 D. The results show that: with the dip angle changing from 45° to 0°, the solid-coal side of gobside entry begins to form an L-shaped stress concentration zone at a dip angle of 30°, and the stress concentration degree goes to higher and higher levels. However, the stress concentration degree of the coalpillar side goes to lower and lower levels; the influence range and peak stress of the abutment at the lateral strata of adjacent gob increase with dip angle decreasing and reach a maximum value at a dip angle of 0°, but the tailgate is not affected; the abutment pressure superposition of two adjacent gobs leads to stress concentration further enhancing in both sides of gob-side entry. With the influence of strong mining disturbance, rock burst is easily induced by dynamic and static combined load in the advanced segment of gob-side entry. To achieve stability control similar to that in the roadway, the key control strategy is to reinforce surrounding rock and unload both sides. Accordingly, the large-diameter drilling and high-pressure water injection combined unloading and reinforced support cooperative control technology was proposed and applied in field test. The results of Electromagnetic Emission(EME) and field observation showed that unloading and surrounding rock control effect was obvious.

家政进社区的实践探索——基于南通市“江海好阿姨”的案例

家政进社区是有效应对人口形势,促进家政服务业提质扩容的关键环节。目前家政进社区存在企业与社区联动性弱、企业认知不足、社区家政服务规范化标准化建设不足、服务质量滞后于需求的难点。南通市“江海好阿姨”社区智慧家政服务驿站的实践表明,家政企业加强与政府、社区和社会团体的良性联动,注重经济效益和社会效益的统一,优化服务流程助力社区家政服务规范性的提升,加强员工培训提高服务队伍的质量等举措,有助于突破家政进社区难点。为此,政府应明确角色主体责任,建立社会支持体系;企业应增强服务民生的意识,加强数字家政建设满足多样化需求;社区应强化监督角色,共建“政府监管、社区监理、企业自检”的社区服务质量管理体系,如此推进家政企业进驻难、扎根难、经营难等问题的解决,同时助力家政进社区行动深入开展,回应社会民生。

UNDERWATER ACOUSTICS AND CAVITATING FLOW OF WATER ENTRY

The fluid mechanics of water entry is studied through investigating the underwater acoustics and the supercavitation.Underwater acoustic signals in water entry are extensively measured at about 30 different positions by using a PVDF needle hydrophone.From the measurements we obtain (1)the primary shock wave caused by the impact of the blunt body on free surface;(2)the vapor pressure inside the cavity;(3)the secondary shock wave caused by pulling away of the cavity from free surface;and so on.The supercavitation induced by the blunt body is observed by using a digital high-speed video camera as well as the single shot photography.The periodic and 3 dimensional motion of the supercavitation is revealed.The experiment is carried out at room temperature.

酱香型白酒面糟入窖方式的研究

酱香型白酒三大典型体中,酱香主要来源于面糟。为了提高酱香白酒的入库合格率,本研究对大综糟醅和面糟分批入窖池的方法进行研究,结果表明面糟入窖的方式影响其出酒质量。本研究提高了出酒质量,增加了企业营收,为提升酱香白酒的入库合格率提供了新的思路,对酱香白酒的长远发展具有重要意义。

Integrated Entry Guidance for Reusable Launch Vehicle

A method for the implementation of integrated three-degree-of-freedom constrained entry guidance for reusable launch vehicle is presented. Given any feasible entry conditions, terminal area energy management interface conditions, and the reference trajectory generated onboard then, the method can generate a longitudinal guidance profile rapidly, featuring linear quadratic regular method and a proportional-integral-derivative tracking law with time-varying gains, which satisfies all the entry corridor constraints and meets the requirements with high precision. Afterwards, by utilizing special features of crossrange parameter, establishing bank-reversal corridor, and determining bank-reversals according to dynamically adjusted method, the algorithm enables the lateral entry guidance system to fly a wide range of missions and provides reliable and good performance in the presence of significant aerodynamic modeling uncertainty. Fast trajectory guidance profiles and simulations with a reusable launch vehicle model for various missions and aerodynamic uncertainties are presented to demonstrate the capacity and reliability of this method.

HYDRODYNAMIC BEHAVIOR OF AN UNDERWATER MOVING BODY AFTER WATER ENTRY

An experimental study was conducted to investigate the water entry phenomenon. A facility was designed to carry out the tests with the entry veloci- ties of around 352 m/s. Visualization, pressure ineasurement, velocity measurement and underwater impact test were performed to investigate the hydroballistic behav- ior of the underwater moving body, the underwater flow field, the supercavitation, etc.. This study shows that the motion of a high-speed underwater body is strongly three-dimensional and chaotic. Furthermore, it is found that the distribution of the trajectory deflection of the underwater projectile depends on the depth of water. It is also found by measuring the deformation on a witness plate submerged in water, that the impact energy of an underwater projectile is reduced as it penetrates deeper into water.

Surrounding rock control of gob-side entry driving with narrow coal pillar and roadway side sealing technology in Yangliu Coal Mine

Gob-side entry driving can increase coal recovery ratio, and it is implied in many coal mines. Based on geological condition of 10416 working face tailentry in Yangliu Coal Mine, the surrounding rock deformation characteristics of gob-side entry driving with narrow coal pillar is analysed, reasonable size of coal pillar and reasonable roadway excavation time after mining are achieved. Surrounding rock control technology and effective roadway side sealing technology are proposed and are taken into field practice. The results showed that a safer and more efficient mining of working face can be achieved. In addition, results of this paper also have important theoretical significance and valuable reference for surrounding rock control technology of gob-side entry driving with narrow coal pillar under special geological condition.

How hepatitis C virus invades hepatocytes: The mystery of viral entry

Hepatitis C virus(HCV)infection is a global health problem,with an estimated 170 million people being chronically infected.HCV cell entry is a complex multi-step process,involving several cellular factors that trigger virus uptake into the hepatocytes.The high-density lipoprotein receptor scavenger receptor class B type I,tetraspanin CD81,tight junction protein claudin-1,and occludin are the main receptors that mediate the initial step of HCV infection.In addition,the virus uses cell receptor tyrosine kinases as entry regulators,such as epidermal growth factor receptor and ephrin receptor A2.This review summarizes the current understanding about how cell surface molecules are involved in HCV attachment,internalization,and membrane fusion,and how host cell kinases regulate virus entry.The advances of the potential antiviral agents targeting this process are introduced.

New insights into store-independent Ca^(2+) entry: secretory pathway calcium ATPase 2 in normal physiology and cancer

Recent studies in secretory pathway calcium ATPases （SPCA） revealed novel functions of SPCA2 in interacting with store-operated Ca2＋ channel Oral I and inducing Ca2＋ influx at the cell surface. Importantly, SPCA2-mediated Ca2＋ signaling is uncoupled from its conventional role of Ca2＋-ATPase and independent of store-operated Ca2＋ signaling pathway. SPCA2-induced store-independent Ca2＋ entry （SICE） plays essential roles in many important physiological processes, while unbalanced SICE leads to enhanced cell proliferation and tumorigenesis. Finally, we have summarized the clinical implication of SICE in oral cancer prognosis and treatment. Inhibition of SICE may be a new target for the development of cancer therapeutics.