Interspecific Differences in Diet between Introduced Red-eared Sliders and Native Turtles in China

Although the alien Red-eared slider （Trachemys scripta elegans） is generally argued as an invasive species that competes with native turtles, the field evidence on its diet is controversial. Field studies conducted at the Gutian Nature Reserve of Guangdong and along the Wanquan River in Hainan, China show that T. s. elegans is an opportunitic omnivore, consuming a wide variety of food items. Consumption varies throughout its range; more plant material is consumed in Guangdong, compared to a more carnivorous diet in Hainan; and juveniles are also found to have a more carnivorous diet than adults. This implies a high adaptability to new environment. Sympatrie native Mauremys sinensis shows a more herbivorous diet and a narrower niche breadth （0.0260） in Hainan, plus a low niche overlap （0.3048） with T. s. elegans, providing a potential empty niche for the invasive T. s. elegans. Red-eared slider is also known to consume large quantities of native prey species to disrupt the ecological balance. It is imperative to understand the invasive nature of this species and the mechanisms by which it affects native ecology.

Packet-loss-dependent stabilization of NCSs with network-induced delay and packet dropout

This paper is concerned with controller design of net- worked control systems （NCSs） with both network-induced delay and arbitrary packet dropout. By using a packet-loss-dependent Lyapunov function, sufficient conditions for state/output feedback stabilization and corresponding control laws are derived via a switched system approach. Different from the existing results, the proposed stabilizing controllers design is dependent on the packet loss occurring in the last two transmission intervals due to the network-induced delay. The cone complementary lineara- tion （CCL） methodology is used to solve the non-convex feasibility problem by formulating it into an optimization problem subject to linear matrix inequality （LMI） constraints. Numerical examples and simulations are worked out to demonstrate the effectiveness and validity of the proposed techniques.

The Ellipsoidal Invariant Set of Fractional Order Systems Subject to Actuator Saturation:The Convex Combination Form

The domain of attraction of a class of fractional order systems subject to saturating actuators is investigated in this paper. We show the domain of attraction is the convex hull of a set of ellipsoids. In this paper, the Lyapunov direct approach and fractional order inequality are applied to estimating the domain of attraction for fractional order systems subject to actuator saturation. We demonstrate that the convex hull of ellipsoids can be made invariant for saturating actuators if each ellipsoid with a bounded control of the saturating actuators is invariant. The estimation on the contractively invariant ellipsoid and construction of the continuous feedback law are derived in terms of linear matrix inequalities (LMIs). Two numerical examples illustrate the effectiveness of the developed method. © 2014 Chinese Association of Automation.

Xylo-oligosaccharides preparation through acid hydrolysis of hemicelluloses isolated from press-lye

The preparation of xylo-oligosaccharides(XOSs)through hydrolysis of hemicelluloses was studied.The hemicelluloses were isolated from the press lye discharged in the production of viscose,which contained about 30%xylan.Then,a factorial experimental design was applied to compare the influences of several factors including the concentrations of sulphuric acid and hemicelluloses,the duration and temperature of the hydrolysis,on the conversion of xylan,and the selectivity for the product–XOSs.The results showed that the hydrolysis duration affects the yield of XOSs to the greatest extent.It is difficult to obtain a high yield of XOSs with sulphuric acid as the hydrolysis catalyst.

Investigation of the kinetic mechanism of the demanganization reaction between carbon-saturated liquid iron and CaF2–CaO–SiO2-based slags

The demanganization reaction kinetics of carbon-saturated liquid iron with an eight-component slag consisting of CaO–SiO2–MgO–FeO–MnO–Al2O3–TiO2–CaF2 was investigated at 1553, 1623, and 1673 K in this study. The rate-controlling step（RCS） for the demanganization reaction with regard to the hot metal pretreatment conditions was studied via kinetics analysis based on the fundamental equation of heterogeneous reaction kinetics. From the temperature dependence of the mass transfer coefficient of a transition-metal oxide（MnO）, the apparent activation energy of the demanganization reaction was estimated to be 189.46 kJ·mol^–1 in the current study, which indicated that the mass transfer of MnO in the molten slag controlled the overall rate of the demanganization reaction. The calculated apparent activation energy was slightly lower than the values reported in the literature for mass transfer in a slag phase. This difference was attributed to an increase in the ＂specific reaction interface＂（SRI） value, either as a result of turbulence at the reaction interface or a decrease of the absolute amount of slag phase during sampling, and to the addition of calcium fluoride to the slag.

Hydrogenolysis of glycerol over HY zeolite supported Ru catalysts

An enhanced active and selective catalyst consisting of ruthenium supported on dealuminated HY zeolite has been prepared by a wet im- pregnation method. It was found that BET surface area of Ru/HY catalysts significantly increases after HC1 treatment. This treatment also increases the concentration of strong acid sites in the catalyst. The hydrogenolysis of glycerol over 5 wt% Ru/HY catalyst was investigated at 190-220℃ , an initial H2 pressure of 3-6 MPa, and in 20 wt% glycerol aqueous solution, The results indicate that HC1 treated Ru/HY catalyst shows higher activity compared with the untreated Ru/HY catalyst, and that the glycerol hydrogenolysis efficiency is influenced by the porosity and acidity of the support. A selectivity to 1,2-PDO of 81.3% at a glycerol conversion of 60.1% under 3 MPa H2 pressure and 220 ℃ for 10 h was achieved over the modified Ru/HY catalyst with a 1.0 mol/L HC1 treatment. It has also been shown that a longer reaction time, a higher temperature and a higher H2 pressure have the positive effects on the glycerol hydrogenolysis efficiency of the enhanced Ru/HY.

Rock physical characteristics of deep dolomite under complex geological conditions:A case study of 4th Member of Sinian Dengying Formation in the Sichuan Basin,China

The deep-ultra deep carbonate reservoir in China,commonly subjected to modification of multi-stage diagenesis,has extremely high heterogeneity.Conventional rock physics analysis cannot accurately identify the elastic responses of reservoir.Here,the rock physics properties of the dolomite from the 4th Member of the Sinian Dengying Formation are experimentally measured,and the change law of rock physics characteristics is investigated within the framework of the diagenetic processes by the analysis of the elastic and petrologic characteristics,pore structure,and sedimentary environments.The results show that the differentiated diagenesis results in different pore structure characteristics and microtexture characteristics of the rock.The microbial dolomite of the algal mound-grain beach facies is subjected to the contemporaneous microbial dolomitization and seepage-reflux dolomitization,penecontemporaneous selective dissolution,burial dolomitization,and hydrothermal dolomitization.The resultant crystalline dolomite is found with one main type of the dolomite crystal contact boundaries,and the dissolution pore is extensive development.The siliceous,muddy,and limy dolomite of the interbeach sea environment mainly experiences the weak capillary concentration dolomitization,intensive mechanical compaction-induced densification,and burial dolomitization.Such crystalline dolomite is observed with four types of contact boundaries,namely the dolomite contact,clay contact,quartz contact,and calcite contact boundaries,and porosity mostly attributed to residual primary inter-granular or crystalline pores.The samples with the same crystal boundary condition have consistent correlations between the compressional-and shear-wave velocities,and between the compressional-wave velocity and the velocity ratio.Additionally,the variation of the acoustic velocity with effective pressure and the intensity of pore-scale fluid-related dispersion are controlled by the differentiation of pore structure types of the samples.The varied effects of soft pores like micro-cracks on the compressional-and shearwave velocity causes considerable changes in the relationships between the compressional-and shearwave velocities,compressional-wave velocity and velocity ratio,and porosity and acoustic velocity.This research is an attempt to demonstrate a novel method for investigating the rock physics variation of rock during the geological process,and the obtained findings can provide the rock physics basis for seismic prediction of the characteristics of deep carbonate reservoirs.

碳纤维复合材料高温界面性能研究进展

碳纤维复合材料以其强度高、耐腐蚀、质量轻、抗疲劳等优良特性被广泛应用于航空航天及国防军工领域。然而,航空航天用复合材料结构部件在高温、湿热环境中会发生界面损伤和失效。上浆剂是碳纤维复合材料界面相的重要组成部分,研制可以增强界面强度和耐高温的上浆剂对提高复合材料的热力学性能具有重要意义。文中从碳纤维表面上浆剂的角度出发,重点介绍了碳纤维复合材料界面特性、上浆剂的作用机理以及高温下复合材料界面的破坏机制。最后,针对环氧上浆剂耐热性差的缺点,阐述了碳纤维耐高温涂层改性和纳米粒子改性,重点介绍了聚酰亚胺、聚醚醚酮、生物活性多巴胺及氧化石墨烯、多面体低聚倍半硅氧烷(POSS)纳米粒子等类型改性上浆剂的研究进展。指出发展环境友好型上浆剂和POSS纳米粒子改性将是下一步工作的重点。

Imaging a force field via an optically levitated nanoparticle array

Levitated optomechanical systems represent an excellent candidate platform for force and acceleration sensing.We propose a force-sensing protocol utilizing an optically levitated nanoparticle array.In our scheme,N nanoparticles are trapped in an optical cavity using holographic optical tweezers.An external laser drives the cavity,exciting N cavity modes interacting simultaneously with the N nanoparticles.The optomechanical interaction encodes the information of the force acting on each nanoparticle onto the intracavity photons,which can be detected directly at the output ports of the cavity.Consequently,our protocol enables real-time imaging of a force field.

肺腺癌细胞EGFR基因过表达和突变通过介导CXCR4/CXCL12信号通路表达导致肿瘤生物学行为改变的机制研究

背景与目的表皮生长因子受体(epidermal growth factor receptor,EFGR)突变与肺腺癌侵袭转移密切相关,CXCR4/CXCL12(chemokine receptor 4/chemokine ligand 12)生物学轴在肿瘤器官特异性转移中发挥重要作用,二者在肺腺癌转移过程中是否存在相互作用尚未明确。本研究旨在探索EGFR过表达和不同位点突变对肿瘤细胞增殖、迁移和侵袭等生物学行为的影响,并探讨其潜在机制。方法构建EGFR过表达、EGFR-E746-A750缺失型(DEL,19号外显子突变)、EGFR-T790M突变型(790M,20号外显子突变)、EGFR-L858R的突变型(LR,21号外显子突变)及EGFR空载质粒,应用Lipofectamine 2000转染H1299肺腺癌细胞。应用细胞克隆实验、细胞划痕实验和Transwell实验分别检测EGFR过表达和突变对H1299细胞增殖、迁移和侵袭能力的影响,并应用RT-PCR和Western blot检测CXCR4、CXCL12,以及该信号通路下游基因MMP-2和MMP-9 m RNA和蛋白表达水平。结果 EGFR过表达和EGFR-E746-A750缺失组细胞克隆形成数目分别为28±2、28.33±4.16,且细胞迁移和侵袭能力显著高于阴性对照组与空白对照组(P<0.05)。RT-PCR和Western blot实验显示EGFR过表达和EGFR-E746-A750缺失组CXCR4、CXCL12、MMP-2和MMP-9的m RNA和蛋白表达水平显著高于阴性对照组和空白对照组(P<0.05)。结论 EGFR基因过表达和19号外显子缺失突变可通过上调CXCR4/CXCL12信号通路,促进MMP-2、MMP-9表达,从而引起肺腺癌细胞的肿瘤生物学特性发生改变,并具有更强的增殖、迁移和侵袭能力。

可交联氟化氮杂环聚芳醚的合成及性能

以4-(4-羟基苯基)-2,3-二氮杂萘酮-1-酮(DHPZ)、双酚AF(6F-BPA)、五氟苯乙烯(FSt)和十氟联苯(DFBP)为原料,通过溶液缩聚反应合成了可交联的FSt-FPPE,所得共聚物的结构通过红外光谱和核磁共振确认与设计一致。FStFPPE呈无定形结构,可溶解在N-甲基吡咯烷酮、N,N-二甲基乙酰胺、N,N-二甲基甲酰胺、氯仿、四氢呋喃等有机溶剂中。与交联剂三聚氰酸三烯丙酯(TAC)进行共固化后,聚合物的玻璃化转变温度由235℃提升至255℃。氮气下热分解温度达497℃,800℃时残碳率为53%。固化后聚合物薄膜的拉伸强度为60~67 MPa,拉伸模量为1.05~1.23GPa,断裂伸长率为10%~12%。当TAC含量为1%时,拉伸强度达到最大值67MPa。在介电性能上,固化后介电常数降低,在10MHz~1GHz的频率下,介电常数在2.4~3.0之间。当TAC含量为3%时,介电常数达到最低值2.4。这些结果表明,FSt-FPPE具有优异的综合性能,在微电子领域中具有一定应用价值。

锌盐类成核剂对聚(1-丁烯)结晶性能的影响

采用偏光显微镜、差示扫描量热仪和傅里叶变换红外光谱仪等方法研究了降冰片烯二羧酸锌(NED-Zn)和ZnO成核剂对聚(1-丁烯)结晶及晶型转变的影响,并用Jeziorny法分析了聚(1-丁烯)的非等温结晶过程。结果表明,2种成核剂的加入使得聚(1-丁烯)的结晶温度升高、结晶速率加快,NED-Zn的成核效果优于ZnO。NED-Zn和ZnO成核剂的存在加快了PB的Ⅱ-Ⅰ晶型转变,使Ⅱ-Ⅰ半转变时间由39.2 h分别缩短至8.1 h和19.2 h。

Effect of sodium alginate on reverse flotation of hematite and its mechanism

Given the gradual increase in the chlorite content of hematite ores, pulp properties seriously deteriorate during flotation. The traditional anion reverse flotation of hematite cannot effectively eliminate the effects of chlorite, leading to a significant decrease in the total Fe(TFe) grade of the concentrate. In this work, the effect of sodium alginate on the reverse flotation of hematite was systematically investigated. Flotation tests of artificially mixed ores were conducted, and the results showed that sodium alginate can significantly improve the removal rates of quartz and chlorite. The adsorption measurements, infrared spectroscopy, and contact angle tests demonstrated that sodium alginate adsorbs on the quartz surface by chelating with calcium ions, thereby weakening the steric hindrance of oleate ions and increasing the adsorption capacity of sodium oleate to ultimately improve the removal rate of quartz. Furthermore, owing to its lower density and fine particle size, chlorite is easily entrained into the foam layer. Sodium alginate dramatically increases the liquid-to-gas ratio of the foam layer by increasing pulp viscosity, thereby increasing the entrainment rate of chlorite and finally improving its removal rate. The core content of this thesis bears significance in improving the Fe grade in the reverse flotation of chlorite-containing hematite.

One-step synthesis of Pt@ZIF-8 catalyst for the selective hydrogenation of 1,4-butynediol to 1,4-butenediol

A catalyst consisting of platinum nanoparticles on a ZIF-8 support（Pt@ZIF-8） was synthesized in a straightforward one-step procedure,by adding a nanostructured platinum sol during the formation of ZIF-8 at room temperature.Pt@ZIF-8 was highly porous and well crystallized.The Pt nanoparticles were well dispersed within the ZIF-8 support.In the hydrogenation of 1,4-butynediol,Pt@ZIF-8 exhibited high activity,excellent selectivity for 1,4-butenediol of greater than 94%,and reusability.The Pt@ZIF-8 catalyst did not require further additives.The favorable catalytic performance was attributed primarily to the modification of the ZIF-8 support by the platinum nanoparticles.

Regularized least-squares migration of simultaneous-source seismic data with adaptive singular spectrum analysis

Simultaneous-source acquisition has been recog- nized as an economic and efficient acquisition method, but the direct imaging of the simultaneous-source data produces migration artifacts because of the interference of adjacent sources. To overcome this problem, we propose the regularized least-squares reverse time migration method （RLSRTM） using the singular spectrum analysis technique that imposes sparseness constraints on the inverted model. Additionally, the difference spectrum theory of singular values is presented so that RLSRTM can be implemented adaptively to eliminate the migration artifacts. With numerical tests on a fiat layer model and a Marmousi model, we validate the superior imaging quality, efficiency and convergence of RLSRTM compared with LSRTM when dealing with simultaneoussource data, incomplete data and noisy data.

Research on new beneficiation process of low-grade magnesite using vertical roller mill

We investigated whether the vertical roller mill can be efficiently used in the beneficiation of low-grade magnesite and whether it can improve upon the separation indices achieved by the ball mill.We conducted experiments involving the reverse flotation and positive flotation of low-grade magnesite to determine the optimum process parameters,and then performed closed-circuit beneficiation experiments using the vertical roller mill and ball mill.The results show that the optimum process parameters for the vertical roller mill are as follows:a grinding fineness of 81.6wt%of particles less than 0.074 mm,a dodecyl amine(DDA)dosage in magnesite reverse flotation of 100 g·t?1,and dosages of Na2CO3,(NaPO3)6,and NaOL in the positive flotation section of 1000,100,and 1000 g·t?1,respectively.Compared with the ball mill,the use of the vertical roller mill in the beneficiation of low-grade magnesite resulted in a 1.28%increase in the concentrate grade of MgO and a 5.88%increase in the recovery of MgO.The results of our causation mechanism analysis show that a higher specific surface area and greater surface roughness are the main reasons for the better flotation performance of particles ground by the vertical roller mill in the beneficiation of lowgrade magnesite.

PyWRKY26 and PybHLH3 cotargeted the PyMYB114 promoter to regulate anthocyanin biosynthesis and transport in red-skinned pears

Red pear is favored because of its bright appearance and abundant anthocyanins.Anthocyanin biosynthesis is controlled by transcription factors(TFs)forming regulatory complexes.In red-skinned pears,the WRKY TFs have a significant relationship with anthocyanin biosynthesis,but the molecular mechanism of the WRKY TFs involved in regulating color formation in red-skinned pear is unclear.In this study,the TFs PyWRKY31 and PyWRKY26 were screened as candidate genes for controlling anthocyanin biosynthesis by transcriptome data and bioinformatics analysis.The effect of anthocyanin accumulations after cotransformation of PyWRKY31 or PyWRKY26 with its partners PyMYB10,PyMYB114,and PybHLH3 was verified in tobacco leaves and strawberry receptacles by a transient expression system.RT-qPCR analysis and a dual-luciferase reporter system further confirmed that this cotransformation activated the expression of PyDFR,PyANS,and PyUFGT in anthocyanin biosynthesis and PyGST in anthocyanin transport instead of the PyABC transporter and PyAVP.Furthermore,the cotransformed PyWRKY26 and PybHLH3 could bind to the PyMYB114 promoter,and PyWRKY26 directly activated the transcription of PyMYB114.In addition,the TF PyWRKY26 could interact with PybHLH3,as confirmed by firefly luciferase complementation and yeast two-hybrid(Y2H)assays.These results showed that the interaction of PyWRKY26 and PybHLH3 could cotarget the PyMYB114 promoter,which resulted in anthocyanin accumulation in red-skinned pear.This study further strengthened the understanding of the regulatory mechanism of anthocyanin accumulation and contributed to improving the appearance of red-skinned pears.

Highly stable and selective Ru/NiFe2O4 catalysts for transfer hydrogenation of biomass-derived furfural to 2-methylfuran

Spinel ferrites NiFeOsupported Ru catalysts have been prepared via a simple sol–gel route and applied for converting biomass-derived furfural to 2-methylfuran. The as-prepared catalysts were characterized by thermogravimetric analysis（TG）, Nadsorption–desorption, X-ray diffraction（XRD）, scanning electronic microscopy（SEM）, and X-ray photoelectron spectroscopy（XPS）. Results showed that the catalysts had well-dispersed Ru active sites and large surface area for calcination temperature ranging from 300 to 500 ℃. The conversion of biomass-derived furfural into 2-methylfuran was conducted over Ru/NiFeOthrough catalytic transfer hydrogenation in liquid-phase with 2-propanol as the hydrogen source. A significantly enhanced activity and increased 2-methylfuran yield have been achieved in this study. Under mild conditions（180 ℃ and 2.1 MPa N）, the conversion of furfural exceeds 97% and 2-methylfuran yield was up to 83% over the catalyst containing 8 wt% Ru. After five repeated uses, the catalytic activity and the corresponding product yield remained almost unchanged. The excellent catalytic activity and recycling performance provide a broad prospects for various practical applications.

Properties and homogeneity of 550-MPa grade TMCP steel for ship hull

Ultra low carbon steels by the thermal mechanical control process（TMCP） with less Ni,Cr,and Mo contents have been developed for 550 MPa grade heavy gauge ship hulls and offshore structures.The relationships among microstructures,process,and properties of the studied steel have been investigated.A series of accurate control technologies have been developed for this kind of steel.Cu microalloying and TMCP＋relaxation precipitation control（RPC）＋accelerated cooling process were employed to optimize the mechanical properties and ensure the homogeneity of the 80-mm thick plate.The microstructures of thin plates slightly changed from surface to center,but the micro-structures of the heavy gauge plate（80 mm） changed notably.Adopting the simple composition,it can meet the requirement of thin plates by adopting a few microalloys.As for thick plates（80 mm）,a little higher Cu and Ni contents should be adopted.These steels can meet the needs without tempering.By these ways,the properties of the steels can be optimized,and the cost can be decreased notably.

WUSCHEL-related homeobox1(WOX1)regulates vein patterning and leaf size in Cucumis sativus

In plants,WUSCHEL-related homeobox1(WOX1)homologs promote lamina mediolateral outgrowth.However,the downstream components linking WOX1 and lamina development remain unclear.In this study,we revealed the roles of WOX1 in palmate leaf expansion in cucumber(Cucumis sativus).A cucumber mango fruit(mf)mutant,resulting from truncation of a WOX1-type protein(CsWOX1),displayed abnormal lamina growth and defects in the development of secondary and smaller veins.CsWOX1 was expressed in the middle mesophyll and leaf margins and rescued defects of the Arabidopsis wox1 prs double mutant.Transcriptomic analysis revealed that genes involved in auxin polar transport and auxin response were highly associated with leaf development.Analysis of the cucumber mf rl(round leaf)double mutant revealed that CsWOX1 functioned in vein development via PINOID(CsPID1)-controlled auxin transport.Overexpression of CsWOX1 in cucumber(CsWOX1-OE)affected vein patterning and produced‘butterfly-shaped’leaves.CsWOX1 physically interacted with CsTCP4a,which may account for the abnormal lamina development in the mf mutant line and the smaller leaves in the CsWOX1-OE plants.Our findings demonstrated that CsWOX1 regulates cucumber leaf vein development by modulating auxin polar transport;moreover,CsWOX1 regulates leaf size by controlling CIN-TCP genes.