Numerical Study on the Pulsation Characteristics of An Attached Air Bubble Under A Nearby Oscillating Bubble

Numerical simulations of the non-spherical evolution of a pulsating bubble interacting with a stationary air bubble attached to a fixed structure were performed using a three-dimensional boundary integral method by implementing the mirror image method to simplify the processing of the numerical model. Code validation was accomplished by comparing the numerical results with the laboratory experimental data obtained in our previous study. Complex phenomena were observed, including three types of bubble jet forms, which depended strongly on the distance parameter with respect to the initial location of the bubble from the plate, the bubble strength parameter and the initial air bubble radius parameters. The results of the simulations provide detail insight into interesting bubble jetting phenomena,such as bubble splitting, jets moving away from the plate, and bubble shedding. The dimensionless distance parameter and the initial air bubble radius parameter play a major role in determining the shapes of two bubbles and the jetting direction. The air bubble strength parameter did not change the bubble jet direction but influenced the bubble shape.The detachment of the attached air bubble under oscillating bubble suction was easily observed for a small initial air bubble. These results showed that bubble jetting toward the plate was manipulated through the effect of attached air bubble, and that cavitation-based applications and underwater explosion bubble may benefit from this erosion mitigation approach.

广义逆多项式模的Attached素理想

设R是有单位元1的结合环,(S,≤)是严格全序Artin幺半群,M_R是右R-模,Att(M_R)与Att([M^(S,≤)]_([[R^(S,≤)]]))分别表示模M_R与广义逆多项式模[M^(S,≤)]_([[R^(S,≤)]])的所有Attached素理想组成的集合.该文主要讨论了广义幂级数环[[R^(S;≤)]]广义逆多项式模[[R^(S;≤)]]的Attached素理想的相关性质,证明了在一定条件下,有Att([M^(S,≤)]_([[R^(S,≤)]])={[[PR^(S;≤)]]P∈Att(M_R)}.这一结论表明广义逆多项式模([M^(S,≤)]_([[R^(S,≤)]])的Attached素理想在一定条件下可以用模M_R的Attached素理想来刻画,推广了Annin S在文献[1]中关于斜多项式环上逆多项式模的Attached素理想的相关结论.

Cell-attached膜片上,咖啡因对猪冠状动脉平滑肌细胞K_(Ca)的调节作用

目的:研究咖啡因对猪冠状动脉平滑肌细胞KCa通道的调控机理,以期揭示胞内钙库RyR激活后,局部钙离子浓度升高和KCa的关系。方法:采用急性酶分离方法,应用膜片钳单通道电流记录技术记录大脑皮层神经元猪冠状动脉平滑肌细胞上KCa通道电流活动。电流信号经放大、滤波及A/D、D/A转换后输入微机进行采样和储存。实验数据应用CLAMP9.0软件系统进行数据采集及分析。结果:在cell-attached膜片上咖啡因对KCa通道有明显的作用,咖啡(0.1-5.0 mM)可以增加通道的开放概率(NPo),呈现出浓度依赖性,开放时间延长,关闭时间也随之缩短,而对电流幅值无明显影响,开放概率的增加是通过明显缩短平均关闭时间实现的(n=8,P<0.05);洗去药物后通道活性可以一定程度的恢复到对照水平,再加入一定浓度咖啡因(如1.0mM)可再次激活KCa,激活程度与洗脱前较接近。结论:在细胞贴附式构型上咖啡因浓度依赖性地激活KCa,有饱和性。可能是通过影响胞内信号转导过程而调控KCa活性。

Community structure and controlled factor of attached green algae on the Porphyra yezoensis aquaculture rafts in the Subei Shoal, China

This study analyzes the community structure, the quantity changes of the algae and the effect of important environmental factors and estimates the total biomass of the attached green algae in the survey areas. The study uses data from surveys of the attached green algae on the Porphyra yezoensis aquaculture rafts and data regarding the environmental factors from October 2010 to April 2011 in the Subei Shoal. The attached green algae on the rafts included Ulva prolifera, Capsosiphon groenlandicus, U. linza, U. intestinalis, U. clathrata, and U. cornpressa. The biomass changes of the attached green algae exhibited an inverted parabola： the biomass was the highest （14 898 t） in April, and was the second highest （2 034 t） in November; it was lowest in February （only 729 t） and increased sharply from March to April. The species diversity differed significantly among the seasons. In September and October, when the P. yezoensis aquaculture rafts were initially set up, the attached green algae had a high biodiversity, while from December to the next February, a variety of green algae species coexisted on the rafts, although the biomass was low, and from March to April, as the biomass increased sharply, the species diversity dropped to the minimum. During this time, C. groenlandicus was apparently dominant with the maximum biomass proportion up to 80%, while the U. prolifera proportion increased exponentially to 20% to 40%. The water temperature had a direct regulating effect on the biomass and the species succession of the attached green algae. The estimation of the community dynamics and the biomass of the green algae provided the evidence needed to track the origin of the large-scale green tide in the southern Yellow Sea.

Particle size distribution and property of bacteria attached to carbon fines in drinking water treatment

The quantitative change and size distribution of particles in the effluents from a sand filter and a granular activated carbon （GAC） filter in a drinking water treatment plant were investigated. The average total concentration of particles in the sand filter effluent during a filter cycle was 148 particles/mL, 27 of which were larger than 2 μm in size. The concentration in the GAC effluent （561 particles/mL） was significantly greater than that in the sand filter effluent. The concentration of particles larger than 2 μm in the GAC filter effluent reached 201 particles/mL, with the amount of particles with sizes between 2 μm and 15 μm increasing. The most probable number （MPN） of carbon fines reached 43 unit/L after six hours and fines between 0.45 μm and 8.0 μm accounted for more than 50%. The total concentration of outflowing bacteria in the GAC filter effluent, 350 CFU （colony-forming units） /mL, was greater than that in the sand filter effluent, 210 CFU/mL. The desorbed bacteria concentration reached an average of 310 CFU/mg fines. The disinfection efficiency of desorbed bacteria was lower than 40% with 1.5 mg/L of chlorine. The disinfection effect showed that the inactivation rate with 2.0 mg/L of chloramine （90%） was higher than that with chlorine （70%）. Experimental results indicated that the high particle concentration in raw water and sedimentation effluent led to high levels of outflowing particles in the sand filter effluent. The activated carbon fines in the effluent accounted for a small proportion of the total particle amount, but the existing bacteria attached to carbon fines may influence the drinking water safety. The disinfection efficiency of desorbed bacteria was lower than that of free bacteria with chlorine, and the disinfection effect on bacteria attached to carbon fines with chloramine was better than that with only chlorine.

The contribution of attached Ulva prolifera on Pyropia aquaculture rafts to green tides in the Yellow Sea

Green tides caused by the unusual accumulation of high floating Ulva prolifera have occurred regularly in the Yellow Sea since 2007.The primary source of the Yellow Sea green tides is the attached algae on the Pyropia aquaculture rafts in the Subei Shoal.Ulva prolifera and Blidingia(Italic)sp.are the main species observed on Pyropia aquaculture rafts in the Subei Shoal.We found that U.prolifera has strong buoyancy and a rapid growth rate,which may explain why it is the dominant species of green tides that occur in the China's sea area of the Yellow Sea.The growth rate of floating U.prolifera was about 20%–31%d–1,which was much higher than Blidingia(Italic)sp.There were about 1.7×104 t of attached algae on the Pyropia aquaculture rafts in May 2012.We found that 39%of attached algae could float when the tide rose in the Subei Shoal,and U.prolifera accounted for 63%of the floating algae.Our analysis estimated that about 4000 t of attached U.prolifera floated into the surrounding waters of the Subei Shoal during the recycling period of aquaculture rafts.These results suggest that the initial floating biomass of large-scale green tides in the Yellow Sea is determined by the U.prolifera biomass attached to Pyropia aquaculture rafts,further impacting the scale of the green tide。

HUSTserver:Implementation for Reliable and High-Performance Network Attached Storage System

Network attached storage (NAS) with the properties of improved scalability, simplified management, low cost and balanced price performance, is desirable for high performance storage systems applied to extensive areas. Unfortunately, it also has some disadvantages such as increased network workload, and inconvenience in disaster recovery. To overcome these disadvantages, we propose a channel bonding technique and provide hot backup functions in the designed NAS system, named HUSTserver. Channel bonding means merging multiple Ethernet channels into integrated one, and that the data packets can be transferred through any available network channels in a parallel mode. The hot backup function provides automatic data mirroring among servers. In this paper, we first describe the whole system prototype from a software and hardware architecture view. Then, multiple Ethernet and hot backup technologies that distinguish HUSTserver from others are discussed in detail. The findings presented demonstrate that network bandwidth can be scaled by the use of multiple commodity networks. Dual parallel channels of commodity 100 Mbps Ethernet are both necessary and sufficient to support the data rates of multiple concurrent file transfers. And the hot backup function introduced in our system provides high data accessibility.

Studies on the Attached Cultivation of Filamentous Oleaginous Microalga Tribonema minus

Attached cultivation is a promising method for microalgal biomass production. Filamentous oleaginous microalga Tribonema minus(hereafter T. minus) has shown a remarkable potential for biofuel production in terms of its high lipid content. However, the strain has only been cultivated in suspended cultivation systems including open pond and closed photobioreactors. Here, we attempted to study the attached cultivation of T. minus, which might be helpful for its scale-up cultivation and industrial applications. As the results, the optimal conditions for T. minus growth in the attached biofilm are 200 μmol photons m^-2 s^-1 of light intensity and 5% of CO2, and the maximum biomass density of 223 g m^-2 has been achieved under the light intensity. The non-woven fabric as substratum was found as the best substratum in thin layer attached bioreactor, on which the average biomass productivity of T. minus is about(9.73 ± 2.19) g m^-2)d^-1. Furthermore, two attached bioreactor systems, rotary drum and rotation disc, were designed following the light dilution strategy and introduced into T. minus cultivation. The highest footprint areal biomass productivity of these two systems is 33 and 47.1 g m^-2 d^-1, respectively, much higher than that in suspended cultivation system. The results shows that T. minus can be cultured with attached cultivation method to improve its biomass productivity.

Role of mental health professionals in dealing with the stigma attached to COVID-19

The stigma associated with the disease may be as subtle as avoidance,or dramatic as physical aggression.COVID-19 has begun to cause social disruption by growing disease-related stigma and xenophobia against some cultural,national,racial or religious groups worldwide.1 People of East Asian origin and those with facial features like them,or those with a travel history to areas affected by the outbreak,are especially being subjected to xenophobia in personal contact and online threats.COVID-19 has arisen as an unknown and newly emerged highly contagious infection that has spread rapidly across the globe and is associated with high mortality,leading to fear of encountering those infected.2 Leaders across the world have taken strict measures such as lockdowns and shutdown of various vital services that have caused chaos in people’s lives and increased concerns about the disease.3 Box 1 lists the factors leading to stigmatisation towards those infected with COVID-19.

Effects of forced aeration on community dynamics of free and attached bacteria in copper sulphide ore bioleaching

Bacterial community dynamics and copper leaching with applied forced aeration were investigated during low-grade copper sulphide bioleaching to obtain better bioleaching efficiency.Results illustrated that appropriate aeration improved bacterial concentrations and leaching efficiencies.The highest bacterial concentration and Cu^(2+)concentration after 14-d leaching were 7.61×10^(7) cells·mL^(−1) and 704.9 mg·L^(−1),respectively,at aeration duration of 4 h·d^(−1).The attached bacteria played a significant role during bioleaching from 1 to 7 d.However,free bacteria dominated the bioleaching processes from 8 to 14 d.This phenomenon was mainly caused by the formation of passivation layer through Fe3+hydrolysis along with bioleaching,which inhibited the contact between the attached bacteria and ore.Meanwhile,16S rDNA analysis verified the effect of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans on the bioleaching process.The results demonstrate the importance of free and attached bacteria in bioleaching.

Cyclin B1 is localized to unattached kinetochores and contributes to efficient microtubule attachment and proper chromosome alignment during mitosis

Cyclin B1 是在脊椎动物控制房间周期前进的关键规章的蛋白质。Cyclin B1 绑 CDK1， cyclin 依赖的 kinase 催化子单元，形成通过关键蛋白质的磷酸化安排有丝分裂的建筑群。Cyclin B1 两个都调整 CDK1 和它的潜水艇的激活细胞的本地化，它可能为底层选择批评。这里，我们证明 cyclin B1 被专注于 kinetochore 的外部板在专业版期间中期。这本地化要求蛋白质的 cyclin 盒子区域。Cyclin B1 被微导管附件从单个 kinetochores 代替到锭子杆到 kinetochores，并且这排水量依赖于 dynein/dynactin 建筑群。由基于向量的 siRNA 的 B1 引起在 kinetochores 和微导管之间的低效的附件的 cyclin 的弄空，和染色体排列背叛，并且推迟后期的发作。在它贡献微导管的正确附件到 kinetochores 和染色体的有效排列的地方，我们断定 cyclin B1 在职业人员中期期间在 kinetochores 积累，通过由 cyclin B1-CDK1 的特定的底层的局部性的磷酸化最可能。当微导管附件被完成， Cyclin B1 然后从每 kinetochore 被搬运，并且这本地化可以重定向 cyclin B1-CDK1 的活动并且在锭子集会检查点的激活贡献。

Construction of Crack Perturbation Model and Forward Semi-analytical Model of Attached Eddy Current Sensor

Fatigue damage monitoring is critical metallic structure health monitoring of aircraft.The sensor should be high sensitive,easy to be integrated into structure and well adaptable for poor working conditions.Therefore,an attached eddy current sensor with flexible plane is put forward and its characteristics are analyzed.By extracting material′s conductivity as the crack features,forward semi-analytical model is established and parameter optimizations are carried out.Crack perturbation model of attached eddy current sensor is constructed,and perturbation voltages of sensing channels under three-dimension structural crack are obtained.To verify the sensor′s performance,monitoring experiment on crack extension is conducted under condition of 3 MHz frequency.The validation experimental results show that perturbation model of 2A12-T4 aluminum alloy agrees well with experiment results,and perturbation model errors of four sensing channels are within 25%.The attached eddy current sensor is capable of testing the crack nondestructively and measuring the crack extension quantitatively with the accuracy of 1mm.

Free vibration of a sagged cable with attached discrete elements

An algorithm is presented to analyze the free vibration in a system composed of a cable with discrete elements, e.g., a concentrated mass, a translational spring, and a harmonic oscillator. The vibrations in the cable are modeled and analyzed with the Lagrange multiplier formalism. Some fragments of the investigated structure are modeled with continuously distributed parameters, while the other fragments of the structure are modeled with discrete elements. In this case, the linear model of a cable with a small sag serves as a continuous model, while the elements, e.g., a translational spring, a concentrated mass, and a harmonic oscillator, serve as the discrete elements. The method is based on the analytical solutions in relation to the constituent elements, which, when once derived, can be used to formulate the equations describing various complex systems compatible with an actual structure. The numerical analysis shows that, the method proposed in this paper can be successfully used to select the optimal parameters of a system composed of a cable with discrete elements, e.g., to detune the frequency resonance of some structures.

Comparison of air-borne xylene biodegradation between immobilizedcell biofilter and biofilm attached biofilter

The Bacillus firmus was immobilized into Ca-alginate beads according to the different initial biomass concentration, calcification time and activation time. Three types of immobilized Bacillus firmus beads were packed respectively in trickling biofilter to purify xylene contained waste gases, and the performance of immobilized-cell biofilter was compared with traditional biofilm attached biofilter packed with two types of ceramic pellets. The results showed that three types of immobilized beads had different capabilities for removing xylene and life-spans. Higher initial biomass in immobilized beads resulted in better performance but shorter life-span. Activation process can remarkably enhance the activity of bacteria, and the removal efficiency of xylene can substantially be improved. Calcification time had influence on life-span of immobilized beads. Without acclimation, the cell-entrapped biofilter can obtain the maximum elimination capacity of 92.4 g/（m^3·h）. However, compared with biofilm attached biofilter, it has a poorer intrinsic drawback in volatile organic compounds （VOCs） removal due to the existence of excess mass transfer resistance.

Nitrogen-doped Porous Carbon Derived from Surface-attached Polymer Layers for Oxygen Reduction Reaction under Acidic Conditions

We reported the synthesis of nitrogen-doped carbon using surface-attached polyelectrolyte layers as precursors. The synthesized material has a large surface area of 800 m^2·g^-1 with uniformed pore distribution. Benefitfed from the high pyridinic nitrogen content, the synthesized nitrogen-doped porous carbon material exhibits promising electrocatalytic activity toward oxygen reduction reactions in acidic medium and very high stability against continuous cyclic voltammetry scans. The experimental results demonstrate that surface-attached polyelectrolyte layers are promising carbon and nitrogen sources for the formation of heteroatom-doped porous carbon materials.

Transport Properties of Ferromagnet/Ferromagnetic-Insulator/Ferromagnet Junctions Attached by a Paramagnetic Metal on Two Sides

The electronic-transport properties of ferromagnet/ferromagnetic-insulator/ferromagnet junctions attached on two sides by a paramagnetic metal are analyzed.The tunnel conductance and magnetoresistance are oscillatory functions of the ferromagnet thickness.The exchange coupling between ferromagnets depends on both the magnetic polarization of the conduction electrons and the exchange splitting in all the magnetic layers.

Solid-Contact Perchlorate Sensor with Nanomolar Detection Limit Based on Cobalt Phthalocyanine Ionophores Covalently Attached to Polyacrylamide

Novel solid-contact perchlorate sensors based on cobalt phthalocyanine-C-monocarboxylic acid (I), and cobalt phthalocyanine-C,C,C,C-tetracarboxylic acid (II) as free ionophores and covalently attached to polyacryla- mide (PAA)—ionophores III and IV, respectively were prepared. The all solid-state sensors were constructed by the application of a thin film of a polymer cocktail containing a phthalocyanine ionophore and cetyltrimethylammonium bromide (CTMAB) as a lipophilic cationic additive onto a gold electrode precoated with the conducting polymer poly (3,4-ethylenedioxythiophene) (PEDOT) as an ion and electron transducer. The sensor with 10.3% of ionophore (III) covalently attached to plasticizer-free poly (butyl methacrylate-co-do- decyl methacrylate) (PBDA) exhibited a good selectivity for perchlorate and discriminated many ions, in- cluding F–, Cl–, Br–, I–, SCN–, , S2– and . The covalent attachment of the ionophore to the polymer resulted in a near-Nernstian anionic slope of –62.3 mV/decade whereas a super-Nernstian slope of –79.9 mV/ decade was obtained for the free ionophore. The sensor covered a linear concentration range of 5 × 10–9 - 1 × 10–2 mol?L–1 with a lower detection limit (LDL) of 1 × 10–9 mol?L–1 and gave a stable response over a pH range of 4 - 10.5. The all-solid state sensors were utilized for the selective flow injection potentiometric determination of perchlorate in natural water and human urine samples in the nanomolar concentration range.

Dynamic analysis of elastic screen surface with multiple attached substructures and experimental validation

A feasible method to improve the reliability and processing efficiency of large vibrating screen via the application of an elastic screen surface with multiple attached substructures(ESSMAS) was proposed.In the ESSMAS,every screen rod,with ends embedded into elastomer,is coupled to the main screen structure in a relatively flexible manner.The theoretical analysis was conducted,which consists of establishing dynamic model promoted from the fuzzy structure theory as well as calculating for the equivalent stiffness of each attached structure.According to the numerical simulation using the NEWMARK-β integration method,this assembling pattern significantly leads to the screen surface/rod having larger vibration intensity than that of the corresponding position on screen structure,which specifically,with an averaged acceleration amplitude increasing ratio of 11.37% in theoretical analysis and 20.27% in experimental test.The experimental results,within a tolerant error,also confirm the established model and demonstrate the feasibility of ESSMAS.

Photon-Assisted Heat Generation by Electric Current in a Quantum Dot Attached to Ferromagnetic Leads

Heat generated by electric current in a quantum dot device contacting a phonon bath is studied using the non- equilibrium Green function technique. Spin-polarized current is generated owing to the Zeeman splitting of the dot level. The current＇s strength and the spin polarization are further manipulated by changing the frequency of an applied photon field and the ferromagnetism on the leads. We find that the associated heat by this spin- polarized current emerges even if the bias voltage is smaller than the phonon energy quanta and obvious negative differential of the heat generation develops when the photon frequency exceeds that of the phonon. It is also found that both the strength and the resonant peaks＇ position of the heat generation can be tuned by changing the value and the arrangement configurations of the magnetic moments of the two leads, and then provides an effective method to generate large spin-polarized current with weak heat. Such a result may be useful in designing low energy consumption spintronic devices.