Structure and dynamical properties during solidification of liquid aluminum induced by cooling and compression

The structural transformation from a liquid into a crystalline solid is an important subject in condensed matter physics and materials science. In the present study, first-principles molecular dynamics calculations are performed to investigate the structure and properties of aluminum during the solidification which is induced by cooling and compression. In the cooling process and compression process, it is found that the icosahedral short-range order is initially enhanced and then begin to decay, the face-centered cubic short-range order eventually becomes dominant before it transforms into a crystalline solid.

Carbonatites in China:A review for genesis and mineralization

Carbonatites are commonly related to the accumulation of economically valuable substances such as REE, Cu, and P. The debate over the origin of carbonatites and their relationship to associated silicate rocks has been ongoing for about 45 years, Worldwide, the rocks characteristically display more geochemical enrichments in Ba, Sr and REE than sedimentary carbonate rocks. However, carbonatite＇s geochemical features are disputed because of secondary mineral effects. Rock-forming carbonates from carbonatites at Qinling, Panxi region, and Bayan Obo in China show REE distribution patterns ranging from LREE enrichment to flat patterns. They are characterized by a Sr content more than 10 times higher than that of secondary carbonates. The coarse- and fine-grained dolomites from Bayan Obo H8 dolomite marbles also show similar high Sr abundance, indicating that they are of igneous origin. Some carbonates in Chinese carbonatites show REE （especially HREE） contents and distribution patterns similar to those of the whole rocks. These intrusive carbonatites display lower platinum group elements and stronger fractionation between Pt and lr relative to high-Si extrusive carbonatite. This indicates that most intrusive carbonatites may be carbonate cumulates. Maoniuping and Daluxiang in Panxi region are large REE deposits. Hydrothermal fluorite ore veins occur outside of the carbonatite bodies and are emplaced in wallrock syenite. The fluorite in Maoniuping has Sr and Nd isotopes similar to carbonatite. The Daluxiang fluorite shows Sr and REE compositions different from those in Maoniuping. The difference is reflected by both the carbonatites and rock-forming carbonates, indicating that REE mineralization is related to carbonatites. The cumulate processes of carbonate minerals make fractionated fluids rich in volatiles and LREE as a result of low partition coefficients for REE between carbonate and carbonatite melt and an increase from LREE to HREE. The carbonatite-derived fluid has interacted with wallrock to form REE ore veins. The amount of carbonatite dykes occurring near the Bayan Obo orebodies may support the same mineralization model, i.e. that fluids evolved from the carbonatite dykes reacted with H8 dolomite marble, and thus the different REE and isotope compositions of coarse- and fine-grained dolomite may be related to reaction processes.

Kinetic modeling of gamma-aminobutyric acid production by Lactobacillus brevis based on pH-dependent model and rolling correction

Gamma-aminobutyric acid(GABA)is a natural non-protein functio nal amino acid,which has potential for fermentation industrial production by Lactobacillus brevis.This work investigated the batch fermentation process and developed a kinetic model based on substrate restrictive model established by experimental data from L25(5~6)orthogonal experiments.In this study,the OD600 value of fermentation broth was fixed to constant after reaching its maximum because the microorganism death showed no effect on the enzyme activity of glutamate decarboxylase(GAD).As pH is one of the key parameters in fermentation process,a pH-dependent kinetic model based on radial basis function was developed to enhance the practicality of the model.Furthermore,as to decrease the deviations between the simulated curves and the experimental data,the rolling correction strategy with OD600 values that was measured in real-time was introduced into this work to modify the model.Finally,the accu racy of the rolling corrected and pH-dependent model was validated by good fitness between the simulated curves and data of the initial batch fermentation(pH 5.2).As a result,this pH-dependent kinetic model revealed that the optimal pH for biomass growth is 5.6-5.7 and for GABA production is about 5,respectively.Therefore,the developed model is practical and convenient for the instruction of GABA fermentation production,and it has instructive significance for the industrial scale.

Parallel Nanoimprint Forming of One-Dimensional Chiral Semiconductor for Strain-Engineered Optical Properties

The low-dimensional,highly anisotropic geometries,and superior mechanical properties of one-dimensional(1D) nanomaterials allow the exquisite strain engineering with a broad tunability inaccessible to bulk or thin-film materials.Such capability enables unprecedented possibilities for probing intriguing physics and materials science in the 1-D limit.Among the techniques for introducing controlled strains in 1D materials,nanoimprinting with embossed substrates attracts increased attention due to its capability to parallelly form nanomaterials into wrinkled structures with controlled periodicities,amplitudes,orientations at large scale with nanoscale resolutions.Here,we systematically investigated the strain-engineered anisotropic optical properties in Te nanowires through introducing a controlled strain field using a resist-free thermally assisted nanoimprinting process.The magnitude of induced strains can be tuned by adjusting the imprinting pressure,the nanowire diameter,and the patterns on the substrates.The observed Raman spectra from the chiral-chain lattice of 1D Te reveal the strong lattice vibration response under the strain.Our results suggest the potential of 1D Te as a promising candidate for flexible electronics,deformable optoelectronics,and wearable sensors.The experimental platform can also enable the exquisite mechanical control in other nanomaterials using substrate-induced,on-demand,and controlled strains.

Development of an integrated process for the production of high-purityγ-aminobutyric acid from fermentation broth

γ-Aminobutyric acid(GABA),a natural non-protein amino acid,plays an irreplaceable role in regulating the life activities of organisms.Nowadays,the separation and purification of food-grade GABA from fermentation broth is still a great challenge.This research utilized monosodium glutamate as a substrate for the production of high-purity GABA via an integrated process incorporating fermentation,purification,and crystallization.Firstly,147 g·L^(-1) GABA with a yield of 99.8%was achieved through fed-batch fermentation by Lactobacillus brevis CE701.Secondly,three integrated purification methods by ethanol precipitation were compared,and crude GABA with a purity of 89,85%was obtained by the optimized method.Thirdly,GABA crystals with a purity of 98.69%and a yield of 60%were further obtained through a designed crystallization process.Furthermore,the GABA industrial production process model was established by Superproper Designer V10 software,and material balance and economic analysis were carried out.Ethanol used in the process was recovered with a recovery of 98.79%through Aspen simulated extractive distillation.Then the fixed investment(equipment purchase and installation costs)for an annual production of 80 t GABA will be about 833000 USD;the total annual production cost(raw material cost and utility cost)will be about 641000 USD.The annual sale of GABA may be at the range of 2400000-4000000 USD and the payback period will be about 1-2 year.This integrated process provides a potential way for the industrial-scale production of food-grade GABA.

Hybrid Dynamic Variables-Dependent Event-Triggered Fuzzy Model Predictive Control

This article focuses on dynamic event-triggered mechanism(DETM)-based model predictive control(MPC) for T-S fuzzy systems.A hybrid dynamic variables-dependent DETM is carefully devised,which includes a multiplicative dynamic variable and an additive dynamic variable.The addressed DETM-based fuzzy MPC issue is described as a “min-max” optimization problem(OP).To facilitate the co-design of the MPC controller and the weighting matrix of the DETM,an auxiliary OP is proposed based on a new Lyapunov function and a new robust positive invariant(RPI) set that contain the membership functions and the hybrid dynamic variables.A dynamic event-triggered fuzzy MPC algorithm is developed accordingly,whose recursive feasibility is analysed by employing the RPI set.With the designed controller,the involved fuzzy system is ensured to be asymptotically stable.Two examples show that the new DETM and DETM-based MPC algorithm have the advantages of reducing resource consumption while yielding the anticipated performance.

Identification of key genes regulating the synthesis of quercetin derivatives in Rosa roxburghii through integrated transcriptomics and metabolomics

Rosa roxburghii fruit is rich in flavonoids, but little is known about their biosynthetic pathways. In this study, we employed transcriptomics and metabolomics to study changes related to the flavonoids at five different stages of R. roxburghii fruit development. Flavonoids and the genes related to their biosynthesis were found to undergo significant changes in abundance across different developmental stages, and numerous quercetin derivatives were identified. We found three gene expression modules that were significantly associated with the abundances of the different flavonoids in R. roxburghii and identified three structural UDP-glycosyltransferase genes directly involved in the synthesis of quercetin derivatives within these modules. In addition, we found that RrBEH4, RrLBD1 and RrPIF8could significantly increase the expression of downstream quercetin derivative biosynthesis genes. Taken together,these results provide new insights into the metabolism of flavonoids and the accumulation of quercetin derivatives in R. roxburghii.

Influence of tartrate on leaching interface of low-grade polymetallic complex chalcopyrite ore

The leaching of Cu from low-grade polymetallic complex chalcopyrite ore(LPCCO)in acidic ferric electrolyte was increased by adding tartrate.To explain the reason resulting in this phenomenon,a systematical study about the effects of tartrate on the interfaces where reactions occurred was conducted by using electrochemical methods.The Mott−Schottky experiment results showed that whether tartrate was added or not,the initial n-type LPCCO surface transformed to the surface with a p−n junction that seriously hindered charge transfer.After adding tartrate,a shorter Debye length and higher charge carrier density were obtained,which were related to the decrease in intergranular energy barrier height by tartrate’s bridging semiconductor particles.Additionally,EIS results combined with Tafel and LSV analysis revealed thin passive film and double-layer,large diffusion coefficient,and low apparent activation energy.These favorable changes in interface properties facilitated the LPCCO dissolution.

Structural behavior and metallization of AsSbS_(3) at high pressure

The group V–VI semiconductor material getchellite (crystalline AsSbS_(3)) has garnered extensive attention due to itswonderful electronic and optical properties. The pressure engineering is one of the most effective methods to modulatecrystal structure and physical properties of semiconductor materials. In this study, the structural behavior, optical and electricalproperties of AsSbS_(3) under high pressure have been investigated systematically by in situ high-pressure experimentsfor the first time. The monoclinic structure of AsSbS_(3) remains stable up to 47.0 GPa without phase transition. The graduallattice contraction with increasing pressure results in a continuous narrowing of the bandgap then leads to pressure-inducedmetallization of AsSbS_(3) at 31.5 GPa. Our research presents a high-pressure strategy for tuning the crystal structure andphysical properties of AsSbS_(3) to expand its potential applications in electronic and optoelectronic fields.

Pressure-Induced Distinct Self-Trapped Exciton Emission in Sb^(3+)-Doped Cs_(2)NaInCl_(6)Double Perovskite

The Cs_(2)NaInCl_(6) double perovskite is one of the most promising lead-free perovskites due to its exceptional stability and straightforward synthesis.However,it faces challenges related to inefficient photoluminescence.Doping and high pressure are employed to tailor the optical properties of Cs_(2)NaInCl_(6).Herein,Sb^(3+)doped Cs_(2)NaInCl_(6)(Sb^(3+):Cs_(2)NaInCl_(6)) was synthesized and it exhibits blue emission with a photoluminescence quantum yield of up to 37.3%.Further,by employing pressure tuning,a blue stable emission under a very wide range from 2.7 GPa to 9.8 GPa is realized in Sb^(3+):Cs_(2)NaInCl_(6).Subsequently,the emission intensity of Sb^(3+):Cs_(2)NaInCl_(6) experiences a significant increase(3.3 times)at 19.0 GPa.It is revealed that the pressure-induced distinct emissions can be attributed to the carrier self-trapping and detrapping between Cs_(2)NaInCl_(6) and Sb^(3+).Notably,the lattice compression in the cubic phase inevitably modifies the band gap of Sb^(3+):Cs_(2)NaInCl_(6).Our findings provide valuable insights into effects of the high pressure in further boosting unique emission characteristics but also offer promising opportunities for development of doped double perovskites with enhanced optical functionalities.

COX-2在子宫内膜异位症中的表达及意义

目的观察环氧合酶-2(COX-2)在子宫内膜异位症中的表达,并比较其在正常对照子宫内膜中的表达差异。方法选取2017年1月1日—2017年12月31日于湖南省妇幼保健院妇科手术切除且经病理确诊为卵巢子宫内膜异位囊肿患者36例,根据选取的不同组织分为异位内膜组和在位内膜组。选取同期于该院就诊的子宫内膜标本正常患者25例作为对照组。用免疫组织化学法检测各组COX-2的表达差异。结果异位内膜组和在位内膜组COX-2表达强度高于对照组(P<0.05)。在位内膜组增生期和分泌期的COX-2表达强度高于对照组(P<0.05),异位内膜组美国生育协会分期Ⅰ、Ⅱ期和Ⅲ、Ⅳ期COX-2表达强度高于对照组(P<0.05)。结论COX-2可能在子宫内膜异位症的发生中发挥作用。

Study on Ability of Ground Cover Plant of Taiyuan to Adsorb PM(2.5)

Four ground cover plant species of Taiyuan（ Iris,Hemerocallis,Sedum,Hosta） were selected to study their capacities in adsorbing PM（2.5）. Meanwhile,the concentration of PM（2.5） in Taiyuan between April 2017 and August 2017 was recorded,and the characteristics of PM（2.5） pollution in summer and autumn in Taiyuan were studied. The results showed that for the 4 plants,the ability to adsorb PM（2.5） was in the order from great to small of Hosta,Iris,Hemerocallis,Sedum,in which H. plantaginea had the best effect to adsorb PM（2.5）. The fresh weight and dry weight per gram of H. plantaginea were 4. 4 times and 2 times higher than those of S. spectabile,while the mass quality of dust adsorption was 2.8 times higher. The sorting result was the same as the ability to adsorb PM（2.5） of unit leaf area. The result of the coefficient of purification showed that the purification coefficients of 3 vegetation structure were positive,and the combination of trees and shrubs in university campus had strong PM（2.5） adsorption capacity. By comparing the seasonal variation of PM（2.5） concentration in Taiyuan city,it found that the PM（2.5） concentration was particularly high in late spring and early summer of Taiyuan,when most of the ground cover plants were not fully grown. Therefore,ground cover plants played an important role in the construction of landscape and the regulation of ecological environment in Taiyuan.

芦苇秸秆纤维改性及与聚乳酸的共混

秸秆天然纤维作为填料或增强材料可应用于复合材料领域,但由于其存在大量的亲水基团,与非极性聚合物材料界面相容性差影响着复合材料的性能,因此对植物纤维的化学改性成为改善界面结合的有效手段。文中采用固相力化学法制备马来酸酐酯化改性芦苇秸秆(MA-RS),扫描电镜(SEM)观察到马来酸酐结合外力的作用下秸秆发生解纤,纤维具有较高长径比;同时红外光谱及X射线光电子能谱测试表明,纤维表面马来酸酐基团的取代度随处理时间的延长而逐渐增大。改性秸秆与聚乳酸共混制备得到复合材料,由于马来酸酐的接枝改变秸秆纤维表面性质,提高了秸秆纤维与聚乳酸之间的相容性和界面结合力。力学测试结果表明,拉伸强度提高约16%,冲击强度提高约30%;SEM观察断面形貌表面,改性秸秆比未改性秸秆与PLA基体具有更好的界面相容性。

邻二氮菲合铁(Ⅱ)组成及稳定常数测定实验的改进与优化

“分光光度法测定邻二氮菲合铁(Ⅱ)组成及稳定常数”是化学类及相关专业广泛开设的经典实验。随着各高校实验条件的完善和进步,有必要对此实验进行系统化设计,以适应对学生培养质量的进一步提升要求。本文中,利用紫外-可见分光光度计测试配合物的紫外-可见吸收曲线,确定检测波长;结合配合物的前线轨道对配位显色机理进行解释。利用Origin软件对实验数据进行分析,得到准确、可靠的实验结果。通过内容的改进与扩充,本实验有助于提高教学训练的系统性与综合性,实现对学生科学思维能力的培养。

Interface electron collaborative migration of Co–Co3O4/carbon dots:Boosting the hydrolytic dehydrogenation of ammonia borane

Ammonia borane(AB)is an excellent candidate for the chemical storage of hydrogen.However,its practical utilization for hydrogen production is hindered by the need for expensive noble-metal-based catalysts.Herein,we report Co-Co3O4 nanoparticles(NPs)facilely deposited on carbon dots(CDs)as a highly efficient,robust,and noble-metal-free catalyst for the hydrolysis of AB.The incorporation of the multiinterfaces between Co,Co3O4 NPs,and CDs endows this hybrid material with excellent catalytic activity(rB=6816 mLH2 min^-1 gCo^-1)exceeding that of previous non-noble-metal NP systems and even that of some noble-metal NP systems.A further mechanistic study suggests that these interfacial interactions can affect the electronic structures of interfacial atoms and provide abundant adsorption sites for AB and water molecules,resulting in a low energy barrier for the activation of reactive molecules and thus substantial improvement of the catalytic rate.

Effect of acoustic stimuli in patients with disorders of consciousness: a quantitative electroencephalography study

Auditory stimuli are proposed as beneficial neurorehabilitation methods in patients with disorders of consciousness. However, precise and accurate quantitative indices to estimate their potential effect remain scarce. Fourteen patients were recruited from the Neuro-Rehabilitation Unit of Hangzhou Hospital of Zhejiang Armed Police Corps of China. Altogether, there were seven cases of unresponsive wakefulness syndrome（five males and two females, aged 45.7 ± 16.8 years） and seven cases of minimally conscious state（six males and one female, aged 42.3 ± 20.8 years）. Simultaneously, fourteen healthy controls（10 males and 4 females, aged 51.7 ± 9.7 years） also participated in this case-control experiment. Brain response to music, subjects＇ own name, and noise was monitored by quantitative electroencephalography（QEEG） in the resting state and with acoustic stimulation. Predictive QEEG values in various brain regions were investigated. Our results show that cerebral activation was high in subjects stimulated by their own name, especially in the temporal lobe in patients with disorders of consciousness, and the frontal lobe in the control group. Further, during resting and stimulation, QEEG index（δ ＋ θ/α ＋ β ratio） negatively correlated with the Coma Recovery Scale-Revised score in traumatic disorders of consciousness patients. Hence, we speculate that a subject＇s own name might be an effective awakening therapy for patients with disorders of consciousness. Moreover, QEEG index in specific stimulation states may be used as a prognostic indicator for disorders of consciousness patients（sensitivity, 75%; specificity, 50%）.

地塞米松玻璃体植入剂应用进展

地塞米松玻璃体植入剂(DEX)是一种装载0.7mg地塞米松的可生物降解的缓释植入物,其适应证主要有视网膜静脉阻塞继发黄斑水肿(RVO-ME)、糖尿病黄斑水肿(DME)和非感染性葡萄膜炎(NIU)。DEX的应用中不良事件主要有眼压升高和白内障,也正因此DEX在RVO-ME、DME的治疗中属于二线用药,多在抗血管内皮生长因子(VEGF)治疗无应答时使用,但DEX在人工晶状体眼或不愿频繁注药的患者中能发挥出其特定的优势。近来很多研究证实了DEX治疗NIU的有效性和安全性,但其在NIU治疗中的地位尚不明确。本文综述了DEX相关的重大临床试验结果,分析其应用进展和安全性。

Gold Nanostars-AIE Theranostic Nanodots with Enhanced Fluorescence and Photosensitization Towards Effective Image-Guided Photodynamic Therapy

Dual-functional aggregation-induced photosensitizers(AIE-PSs)with singlet oxygen generation(SOG)ability and bright fluorescence in aggregated state have received much attention in image-guided photodynamic therapy(PDT).However,designing an AIE-PS with both high SOG and intense fluorescence via molecular design is still challenging.In this work,we report a new nanohybrid consisting of gold nanostar(AuNS)and AIE-PS dots with enhanced fluorescence and photosensitization for theranostic applications.The spectral overlap between the extinction of AuNS and fluorescence emission of AIE-PS dots(665 nm)is carefully selected using five different AuNSs with distinct localized surface plasmon(LSPR)peaks.Results show that all the AuNS s can enhance the 1 O2 production of AIE-PS dots,among which the AuNS with LSPR peak at 585 nm exhibited the highest 1 O2 enhancement factor of15-fold with increased fluorescence brightness.To the best of our knowledge,this is the highest enhancement factor reported for the metalenhanced singlet oxygen generation systems.The Au585@AIE-PS nanodots were applied for simultaneous fluorescence imaging and photodynamic ablation of HeLa cancer cells with strongly enhanced PDT efficiency in vitro.This study provides a better understanding of the metal-enhanced AIE-PS nanohybrid systems,opening up new avenue towards advanced image-guided PDT with greatly improved efficacy.

Robust Consensus Tracking Control of Uncertain Multi-Agent Systems With Local Disturbance Rejection

In this paper,a new distributed consensus tracking protocol incorporating local disturbance rejection is devised for a multi-agent system with heterogeneous dynamic uncertainties and disturbances over a directed graph.It is of two-degree-of-freedom nature.Specifically,a robust distributed controller is designed for consensus tracking,while a local disturbance estimator is designed for each agent without requiring the input channel information of disturbances.The condition for asymptotic disturbance rejection is derived.Moreover,even when the disturbance model is not exactly known,the developed method also provides good disturbance-rejection performance.Then,a robust stabilization condition with less conservativeness is derived for the whole multi-agent system.Further,a design algorithm is given.Finally,comparisons with the conventional one-degree-of-freedombased distributed disturbance-rejection method for mismatched disturbances and the distributed extended-state observer for matched disturbances validate the developed method.

Robust Fuzzy Tracking Control for Nonlinear Networked Control Systems with Integral Quadratic Constraints

This paper investigates the robust tracking control problcm for a class of nonlinear networked control systems （NCSs） using the Takagi-Sugeno （T-S） fuzzy model approach. Based on a time-varying delay system transformed from the NCSs, an augmented Lyapunov function containing more useful information is constructed. A less conservative sufficient condition is established such that the closed-loop systems stability and time-domain integral quadratic constraints （IQCs） are satisfied while both time-varying network- induced delays and packet losses are taken into account. The fuzzy tracking controllers design scheme is derived in terms of linear matrix inequalities （LMIs） and parallel distributed compensation （PDC）. Furthermore, robust stabilization criterion for nonlinear NCSs is given as an extension of the tracking control result. Finally, numerical simulations are provided to illustrate the effectiveness and merits of the proposed method.