Experimental and numerical investigations on micromixing performance of multi-orifice cross-flow jet mixers

Multi-orifice cross-flow jet mixers(MOCJMs)are used in various industrial applications due to their excellent mixing efficiency,but few studies have focused on the micromixing performance of MOCJMs.Herein,the flow characteristics and micromixing performance inside the MOCJM were investigated using experiments and computational fluid dynamics(CFD)simulations based on the Villermaux/Dushman system and the finite-rate/modified eddy-dissipation model.The optimal A value was correlated with the characteristic parameters of MOCJMs to develop a CFD calculation method applicable to the study of the micromixing performance of the MOCJMs.Then the micromixing efficiency was evaluated using the segregation index XS,and the effects of operational and geometric parameters such as mixing flow Reynolds number(ReM),flow ratio(RF),total jet area(ST),the number of jet orifices(n),and outlet configuration on the micromixing efficiency were investigated.It was found that the intensive turbulent region generated by interactions between jets,as well as between jets and crossflows,facilitated rapid reactions.XS decreased with increasing ReM and decreasing RF.Furthermore,MOCJMs with lower ST,four jet orifices,and the narrower outlet configuration demonstrated a better micromixing efficiency.This study contributes to a deeper understanding of the micromixing performance of MOCJMs and provides valuable guidance for their design,optimization,and industrial application.

神经酰胺复合物对光损伤3D全层皮肤模型的作用研究

通过重建光损伤3D全层皮肤模型,利用石蜡切片免疫组化、免疫荧光染色等办法,观察样本细胞、组织形态,检测模型细胞外基质Ⅰ型胶原蛋白,表皮屏障蛋白FLG、CLDN-1、LCE-A1以及相关应激酶的含量变化,评估神经酰胺复合物对光损伤的成年皮肤真表皮层的影响。实验发现神经酰胺复合物可以显著缓解因紫外造成的表皮分化紊乱、胶原蛋白流失、屏障蛋白降低和皮肤应激防御反应,减少皮肤因紫外辐照产生的一系列负面影响,对皮肤光损伤具有预防修护作用。

表面活性剂胶束化物理化学性质研究

通过电导法考查温度和盐浓度对十二烷基硫酸钠(SDS)临界胶束浓度(CMC)的影响,研究表面活性剂形成胶束过程的物理化学性质。根据拟相分离模型求得胶束化热力学函数,并讨论体系电导活化能随温度和SDS浓度变化关系。结果表明:SDS的CMC随温度升高而增加,随氯化钠浓度增大而减小。在热力学上SDS在水溶液中形成胶束是一个自发、放热、熵增的过程;在动力学上,SDS溶液电导率与温度关系符合Arrhenius公式,通过电导活化能信息可揭示离子型表面活性剂形成胶束的机理特征。

Fabrication of chitosan microspheres for efficient adsorption of methyl orange

In this article, morphology, structure and size controllable chitosan microspheres with high mechanical strength were synthesized by microfluidic technology combining chemical crosslinking and used as an adsorbent for methyl orange. The synthesized adsorbents were characterized using scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FTIR), and an Energy Dispersive Spectrometer(EDS). The effect of pH revealed that the adsorption process depended on pH and the pH variation of methyl orange solution after adsorption indicated that adsorption capacity was affected through the associated role of chitosan nature and pH variation. Experimental results suggested that the as-prepared chitosan microspheres were controlled within a narrow size distribution(coefficients of variation is 1.81%), whose adsorption capacity reached to 207 mg·g^(-1) and mechanical strength was suitable to resist forces. In addition, the adsorption isotherm was well fitted with the Langmuir model, and the adsorption kinetic was best described by the pseudo-second-order kinetic model.The high performance microfluidic-synthesized chitosan microspheres have promising potentials in the applications of removing dyes from wastewater.

Gas dispersion and solid suspension in a three-phase stirred tank with triple impellers

The hydrodynamics is still not fully understood in the three-phase stirred tank equipped with multi-impeller due to the intensive interaction between phases.In this work,the solid critical suspension speed(NJSG),relative power demand(RPD)and overall gas holdup(ε_G)were measured in an air–water–glass beads stirred tank equipped with multi-impeller,which consists of a parabolic blade disk turbine below two down-pumping hydrofoils.Results show that either the NJSGor the specific power consumption increases when increasing the volumetric solid concentration or superficial gas velocity.RPD changes less than 10%when solid volumetric concentration ranges from 0 to 15%.ε_G decreases with the increase of solid concentration,and increases with the increase of both superficial gas velocity and the total specific power consumption.The quantitative correlations of NJSG,RPD andεGwere regressed as the function of superficial gas velocity,specific power consumption,Froude number and gas flow number,in order to provide the reference in the design of such three-phase stirred tank with similar multi-impellers.

Genotype Screening of Recipient Resources with High Regeneration and Transformation Efficiency in Chrysanthemum

Genetic transformation is one of the key steps in the molecular breeding of chrysanthemum,which relies on an optimal regeneration and transformation system.However,the regeneration system of different chrysanthemum cultivars varies,and the regeneration time of most cultivars is long.To screen cultivars with highly efficient regeneration,leaves and shoot tip thin cell layers(tTCL)from eight chrysanthemum cultivars with different flower colors and flower types were cultured on Murashige and Skoog media(MS)supplemented with 1.0-5.0 mg L^(−1)6-benzylaminopurine(6-BA)and 0.1-1.0 mg L^(−1)α-naphthaleneacetic(NAA).The results showed that the most efficient regeneration media were MS+6-BA 1.0 mg L^(−1)+NAA 0.5 mg L^(−1)for leaf explants and MS+6-BA 5.0 mg L^(−1)+NAA 0.1 mg L^(−1)for tTCL explants.Subsequently,another 13 chrysanthemum cultivars were screened by using the media,and finally,three cultivars with high regeneration efficiency were obtained from 21 cultivars.Among these,C1 had the highest regeneration efficiency:the regeneration rate of leaf explants reached 80.0%after 42 days of culture,and the regeneration rate of tTCL explants reached 100%after 31 days of culture.Furthermore,we also established the transformation system for C1 as follows:preculturing for one day,infecting with Agrobacterium suspension(OD_(600)=0.6)for 10 min,and cultivating in the regeneration medium with 350 mg L^(−1)carbenicillin and 10 mg L^(−1)kanamycin,thus ultimately achieving a transformation rate of 4.0%.In this study,a new chrysanthemum cultivar with an efficient regeneration and transformation system was screened,which is beneficial to enrich the flower color of chrysanthemum transgenic plant recipients and to the functional research of flower color or type-related genes.

Estimation of dynamic stress spectrum distribution in structural fatigue test

The determination of structural dynamic stress spectrum distribution is of great signifi- cance in the structural fatigue strength evaluation as well as reliability design. In previous empirical data processing methods, the data grouping and distribution fitting were excessively coarse and contained distinctive defects. This paper proposed an effective approach to statistically group actual measured dynamic stress data and validly extrapolate the combined distribution to fit the dynamic stress spectrum distribution. This approach has been verified its effectiveness through chi-square test, stress spectrum extrapolation and damage calculation in dynamic stress study.

Nitride-reinforced HfNbTaTiV high-entropy alloy with excellent room and elevated-temperature mechanical properties

Nitride-reinforced(HfNbTaTiV)_(90)N_(10) high-entropy alloy aiming at high-temperature applications is de-signed in this paper.Abundant FCC nitride phases are formed in situ in theBCC matrix by arc melt-ing technique,without complex deformation or heat treatment.The(HfNbTaTiV)_(90)N_(10) alloy exhibits a remarkable yield strength of 2716 MPa and ultimate compressive strength of 2833 MPa with a plas-tic strain of 10%at room temperature.Besides,the alloy remains a high yield strength of 279 MPa at 1400℃.The nitride phases play an essential role in maintaining the excellent strength-ductility com-bination at room temperature and enhancing the high-temperature softening resistance.Alternating BCC and FCC phases possess the semi-coherent interface,which not only strengthens the BCC matrix but also promotes the compatible deformation of the duplex microstructure.The lattice coherency structure of the semi-coherent interface is conducive to the slip transfer of partial dislocations through the interface,which facilitates the accommodation of plastic deformation.The cross-slip of the screw dislocations ef-fectively eliminates stress concentration and leads to good ductility of the dual-phase alloy.The results demonstrate that the nitride phases achieve coordinate deformation with the matrix without deteriorat-ing the ductility of the(HfNbTaTiV)_(90)N_(10) alloy.

一种新型可充的水系铋-空气电池

水系金属空气电池具有理论能量密度高、安全性高等优点,但受限于金属阳极(如锌、铁、铝、镁)的电化学不可逆性以及碱性电解质对大气中二氧化碳的化学不稳定性.本工作首次设计了一种可充电的铋-空气电池,该电池使用了非碱性的三氟甲磺酸铋(Bi(OTf)_(3))水系电解质.得益于三电子反应和相对于标准氢电极+0.32 V的高电位,铋金属负极具有383 mA h g^(−1)的高比容量和1000次循环的良好稳定性,以及99.6%高库仑效率.铋金属负极在Bi(OTf)_(3)电解液中无腐蚀、钝化和析氢等副反应.此外,非碱性的铋-空气电池通过三氧化二铋(Bi_(2)O_(3))的可逆形成/分解,在环境空气中实现了长期运行稳定性(>200 h).这项工作为探索新型水系金属空气电池作为安全稳定的电源系统提供了新思路.

Amphiphilic core-sheath structured composite fiber for comprehensively performed supercapacitor

As an im portant branch of fiber-shaped energy storage devices, the fiber-shaped supercapacitor has been widely studied recently. However, it remains challenging to simultaneously achieve fast electron transport and excellent ion accessibility in one single fiber electrode of the fibershaped supercapacitor. Herein, a novel family of amphiphilic core-sheath structured carbon nanotube composite fibers has been developed and applied to the fiber-shaped supercapacitor to address the above challenge. The polyaniline-modified hydrophilic sheath of the composite fiber electrode effectively enhanced the electrochemical property via advancing ion accessibility, while Au-deposited hydrophobic core demonstrated improved electrical conductivity by fast electron supply. On the basis of a synergistic effect, a remarkable specific capacitance of 324 F cm^-3 at 0.5 A cm^-3 and greatly enhanced rate performance were achieved, i.e” a 79% retention (256 F cm 3) at 50 A cm^-3. The obtained fiber-shaped supercapacitor finally displayed remarkable energy and power densities of 7.2 mW h cm 3 and 10 W cm^-3, respectively. The strategy developed herein also presents a general pathway towards novel fiber electrodes for high-performance wearable devices.

Microfluidic synthesis of renewable biosorbent with highly comprehensive adsorption performance for copper （II）

A microsphere biosorbent with uniform size （CV = 1.52%）, controllable morphology and component, and high mechanical strength was synthesized from chitosan by microfluidic technology combining with chemical crosslinking and solvent extraction. This chitosan microsphere （CS-MS） was prepared with a two-step solidification process, which was acquired by drying for the enhancement of mechanical property in final. The adsorption behavior of CS-MS towards copper （II） and main influencing factors on adsorption performance were investigated by batch experiments. Kinetic data high-lighted dominant chemical bonding along with electrons transferring in adsorption process. Isothermal analysis indicated that adsorption capacity was relevant to the number of active site. All these explorations provided a new direction for preparing highly comprehensive performance sorbent used in heavy metal treatment via microfluidic technology.

Enhanced high-temperature strength of HfNbTaTiZrV refractory high-entropy alloy via Al_(2)O_(3)reinforcement

Novel composites of HfNbTaTiZrV refractory high-entropy alloy(RHEA)reinforced with 0–4 vol.%Al_(2)O_(3)particles have been synthesized by vacuum arc melting.The microstructure evolution,compressive mechanical properties at room and elevated temperatures,as well as strengthening mechanism of the composites were analyzed.The HfNbTaTiZrV RHEA reinforced with 4 vol.%Al_(2)O_(3)displayed excellent phase stability at elevated temperatures.A superior compressive yield strength of 2700 MPa at room temperature,1392 MPa at 800°C,and 693 MPa at 1000°C was obtained for this composite.The improved yield strength resulted from multiple strengthening mechanisms caused by Al_(2)O_(3)addition,including solution strengthening,interstitial strengthening,grain boundary strengthening,and dispersion strengthening.Besides,the effects of interstitial strengthening increased with temperature and was the main strengthening mechanism at elevated temperatures.These findings not only promote the development of oxidereinforced RHEAs for challenging engineering applications but also provide guidelines for the design of light refractory materials with multiple strengthening mechanisms.

Deformation-tolerant metal anodes for flexible sodium-air fiber batteries

Although flexible sodium-air(Na-air)batteries with high theoretical energy density offer promising opportunities for next-generation smart electronics,enhancing the safety and efficiency of flexible sodium metal anodes under dynamic and continuous deformation remains a challenge.Here,a flexible sodiated carbon nanotube layer to suppress dendrite growth under various deformations is demonstrated through a Fermi level-driven spontaneous synthetic process.The resulting sodiated carbon nanotube layer,which has a spontaneously formed solid-electrolyte interface and a robust interlocked structure,creates a uniformly distributed electric field and stable interface even under deformation,affording dendrite-free flexible Na metal anodes.With this deformation-tolerant Na metal anode,we have constructed a new family of highly flexible Na-air fiber batteries with excellent cycling performance for 400 cycles at a current density of 1000​mA·g^(−1) and a capacity limit of 500 mAh·g^(−1) under dynamic deformation.These Na-air fiber batteries can be further woven into self-powering systems to support flexible electronic devices.

The applications of carbon nanomaterials in fiber-shaped energy storage devices

As a promising candidate for future demand, fiber-shaped electrochemical energy storage devices, such as supercapacitors and lithium-ion batteries have obtained considerable attention from academy to industry. Carbon nanomaterials, such as carbon nanotube and graphene, have been widely investigated as electrode materials due to their merits of light weight, flexibility and high capacitance. In this review, recent progress of carbon nanomaterials in flexible fiber-shaped energy storage devices has been summarized in accordance with the development of fibrous electrodes, including the diversified electrode preparation, functional and intelligent device structure, and large-scale production of fibrous electrodes or devices.

Enhanced electrochemical performance of SnS nanoparticles/CNTs composite as anode material for sodium-ion battery

SnS nanoparticles/CNTs composite （SnS]CNTs composite） is synthesized by a facile one-pot solvothermal reaction. The structural characterizations reveal pure SnS nanoparticles with the size of less than 10 nm distribute on the surface of CNTs with the diameter of less than 20 nm. The SnS]CNTs composite electrode performs high reversible capacity and good cyclability （365 mAh/g at 50 mA/g after 50 cycles）, which is superior to that of pure SnS electrode synthesized without the adding of CNTs （115.9 mAh/g at 50 mA/g after 50mA/ cycles）. Even increasing the current density to 500mA/g, the SnS]CNTs composite electrode still delivers a reversible capacity up to 210 mAh/g after 100 cycles, nearly two times higher than that of the pure SnS electrode （108 mAh/g after 100 cycles）. The rate performance of the SnS/CNTs composite electrode is also better than that of pure SnS electrode at different current densities from 50mA/g to 800mA/g. The enhanced electrochemical performance of SnS/CNTs composite can be attributed to the adding of CNTs as a flexible and conductive structure supporter and the formation of SnS nanoparticles with small size. The SnS nanoparticles[CNTs composite structure not only benefits for buffering the volume change during charge and discharge process, but also increases the surface area for sufficient electrode-electrolyte contacting, and shortens Na＋ diffusion length, which improves the conductivity and stability of active material and finally provides desirable electrochemical performance.

ERα promotes transcription of tumor suppressor gene ApoA-I by establishing H3K27ac-enriched chromatin microenvironment in breast cancer cells

Apolipoprotein A-I(Apo A-I),the main protein component of high-density lipoprotein(HDL),plays a pivotal role in reverse cholesterol transport(RCT).Previous studies indicated a reduction of serum Apo A-I levels in various types of cancer,suggesting Apo A-I as a potential cancer biomarker.Herein,ectopically overexpressed Apo A-I in MDA-MB-231 breast cancer cells was observed to have antitumor effects,inhibiting cell proliferation and migration.Subsequent studies on the mechanism of expression regulation revealed that estradiol(E2)/estrogen receptorα(ERα)signaling activates Apo A-I gene transcription in breast cancer cells.Mechanistically,our Ch IP-seq data showed that ERαdirectly binds to the estrogen response element(ERE)site within the Apo A-I gene and establishes an acetylation of histone 3 lysine 27(H3 K27 ac)-enriched chromatin microenvironment.Conversely,Fulvestrant(ICI 182780)treatment blocked ERαbinding to ERE within the Apo A-I gene and downregulated the H3 K27 ac level on the Apo A-I gene.Treatment with p300 inhibitor also significantly decreased the Apo A-I messenger RNA(m RNA)level in MCF7 cells.Furthermore,the analysis of data from The Cancer Genome Atlas(TCGA)revealed a positive correlation between ERαand Apo A-I expression in breast cancer tissues.Taken together,our study not only revealed the antitumor potential of Apo A-I at the cellular level,but also found that ERαpromotes the transcription of Apo A-I gene through direct genomic effects,and p300 may act as a co-activator of ERαin this process.

Consistent apparent Young’s modulus of human embryonic stem cells and derived cell types stabilized by substrate stiffness regulation promotes lineage specificity maintenance

Background:Apparent Young’s modulus(AYM),which reflects the fundamental mechanical property of live cells measured by atomic force microscopy and is determined by substrate stiffness regulated cytoskeletal organization,has been investigated as potential indicators of cell fate in specific cell types.However,applying biophysical cues,such as modulating the substrate stiffness,to regulate AYM and thereby reflect and/or control stem cell lineage specificity for downstream applications,remains a primary challenge during in vitro stem cell expansion.Moreover,substrate stiffness could modulate cell heterogeneity in the single-cell stage and contribute to cell fate regulation,yet the indicative link between AYM and cell fate determination during in vitro dynamic cell expansion(from single-cell stage to multi-cell stage)has not been established.Results:Here,we show that the AYM of cells changed dynamically during passaging and proliferation on substrates with different stiffness.Moreover,the same change in substrate stiffness caused different patterns of AYM change in epithelial and mesenchymal cell types.Embryonic stem cells and their derived progenitor cells exhibited distinguishing AYM changes in response to different substrate stiffness that had significant effects on their maintenance of pluripotency and/or lineage-specific characteristics.On substrates that were too rigid or too soft,fluctuations in AYM occurred during cell passaging and proliferation that led to a loss in lineage specificity.On a substrate with‘optimal’stiffness(i.e.,3.5 kPa),the AYM was maintained at a constant level that was consistent with the parental cells during passaging and proliferation and led to preservation of lineage specificity.The effects of substrate stiffness on AYM and downstream cell fate were correlated with intracellular cytoskeletal organization and nuclear/cytoplasmic localization of YAP.Conclusions:In summary,this study suggests that optimal substrate stiffness regulated consistent AYM during passaging and proliferation reflects and contributes to hESCs and their derived progenitor cells lineage specificity maintenance,through the underlying mechanistic pathways of stiffness-induced cytoskeletal organization and the downstream YAP signaling.These findings highlighted the potential of AYM as an indicator to select suitable substrate stiffness for stem cell specificity maintenance during in vitro expansion for regenerative applications.

Influence of energy bandwidth of pink beam on small angle X-ray scattering

Background Compared with the traditional monochromatic synchrotron radiation beam,a pink beam is a quasimonochromatic beam which can be obtained by screening a harmonic of the undulator.The energy bandwidth(E/E)of a pink beam is about 10−2.Despite the intensity gain from the quasi-monochromatic beam,the decrease in the energy resolution will lead the collected data to be smeared.Purpose To study the influence of the energy bandwidth on the small angle X-ray scattering(SAXS)by experiments and verify the feasibility of SAXS with a pink beam.Method Firstly,the influence of different energy bandwidths on SAXS has been studied by simulation and experiment.Then,TEM tests have been performed and compared with the experimental results.Result It has been shown that the scattering curves deviate slightly from the traditional monochromatic ones.This deviation does not influence the data processing for the maximum deviation of the results is just less than 2%.In return,the gain in the intensity(one to two orders of magnitude)makes the pink beam very important for the time-resolved SAXS.Further,the results of TEM and SAXS have shown an excellent agreement.Conclusion Thiswork proves that the pink beam could be used for SAXS directly without a desmearing procedure.Benefiting from the increase in the beam intensity,the exposure time can be greatly shortened,thus enhancing the utilization efficiency of the synchrotron radiation.