Through solid state reaction method,the Sr_(0.5)Ln_(0.5)FBiS_2(Ln= La,Ce)polycrystalline samples are synthesized using rare earth elements Lanthanum and Cerium doping into Sr site.The X-ray diffraction measurement,electrical transport and magnetic susceptibility measurements show that the parent sample SrFBiS_2 is a semiconductor.La or Ce doping can induce superconductivity at about 2.8Kin Sr_(0.5)Ln_(0.5)FBiS2(Ln=La,Ce).Meanwhile,Sr_(0.5)Ce_(0.5)FBiS_2 not only orders ferromagnetically below 7.5K,but exhibits superconductivity at 2.8K,implying the coexistence of superconductivity and ferromagnetism.Those findings play an important role in studying the superconducting mechanism in the BiS_2-based superconductors as well as the relationship between superconductivity and ferromagnetism.
USB disk is a mainstream portable storage device that can carry out data interactions,and it brings safer mobile storage with the design of encryption and decryption system for the USB disk.This paper implementes a USB disk encryption and decryption system with SOPC(System on a Programmable Chip)technology,AES algorithm is implemented with Verilog HDL language,the core part adopts Altera Cyclone IV EP4CE15F17C8 FPGA chip,and the interaction with PC engine uses Nios II soft core.Since the encryption and decryption processor and controller are embedded in the FPGA chip in the form of IP soft core,the whole system is highly reconfigurable and compatible.Experimentations verify the functional correctness of the whole system.
Isoprenoids are a large and diverse group of natural products which play important roles in plant metabolic activities.They are also widely used in medicine and industry field,which are synthesized via two distinct pathways,the mevalonate pathway and the 1-deoxy-D-xylulose-5-phosphate pathway. 3-hydroxy-3-methylglutaryl CoA reductase(HMGR),1-deoxy-D-xylulose-5-phosphate synthase(DXS),1-deoxy-D-lxylulose-5-phosphate reductoiso-merase(DXR),isopentenyl transferases and terpene synthases are the key enzymes that regulate isoprenoids synthesis in the two pathways.The research advances of molecular cloning,genetic expression,classification,metabolism and metabolic engineering of these key enzymes were reviewed.
Basing on the principle of activity superposition in drug design,taking 3-methyl-1-phenyl-5-chloro-4-pyrazolocarbaldehyde and hydroquinone as the stating materials,16 novel bi-oxadiazoline derivatives containing pyrazole moiety are synthesized via a series of reactions.The successful completion of the 1,2,4-oxadiazole ring is introduced into pyrazole ring.These compounds are determined by IR,MS,1 H-NMR spectra.
This article modifies the general form of Hawking temperature,and basing on the dynamic effect of second derivative in scale factor a,it reconsiders the coincidence of the ratio of dark energy and dark matter as well as the acceleration of the universe under semi-holographic cosmological models,obtains the kinetic equation of the universe and its attractor solution,and provides the analytical expression of deceleration factor and the equivalent pressure density ratio.After adopting some reasonable parameters,when the deceleration factor is negative,it indicates that the universe is accelerated expanding,The equivalent pressure density ratio of dark energy and dark matter is well consistent with the prospection of semi-holographic cosmology.
A portable demonstrator of polarized light in class is designed and manufactured,and the significance of classroom demo experiments is discussed.The demonstrator of polarized light is made up of an aluminum frame and two large turntables based on the teaching demands of university physics and medical physics.The demonstrator can show the various properties of polarized light,verify the Malus law and reveal the work of saccharometer.The class teaching proves that the demonstrator can contribute to enhance the teaching effects of university physics and medical physics.
Using the DMA4500/RXA170 instrument ,the density and refractive index of 1 ,3 ,5‐trimethyl‐1 ,3 ,5‐tris(3 , 3 ,3‐trifluoropropyl) cyclotrisiloxane with nitrobenzene ,ethylbenzene ,anisole and tert‐butylbenzene at T= 328 .15 K are determined .The excess molar volume ,refractive index deviation ,molar refractive index and molar refractive index deviation are also calculated .The excess molar volumes decrease in the following sequence ,Ethylbenzene> Tert‐butyl benzene>Anisole>Nitrobenzene .The excess refractive indices decrease in the following sequence ,Nitrobenzene > Tert‐butyl benzene>Anisole>Ethylbenzene .
This paper defines weakly almost clean rings.A commutative ring Ris a weakly almost clean ring if every element x∈Rcan be written in the formx=r+e or x=r-e where r∈reg(R)and e∈Id(R).Firstly,for a nonempty collection{Ri}of rings Ri,the product R =∏if and onl∈IRiis weakly almost clean iy if there exists m∈Isuch that Rmis weakly almost clean and Rnis almost clean for all n≠m.Further,let Rbe a ring and M be an R-module,the trivial extension R(M)of Rand Mis weakly almost clean if and only if each x∈Rcan be written in the formx=r+e or x=r-e where r∈R-(Z(R)∪Z(M))and e∈Id(R).These extend the corresponding results on almost clean rings.
Recently ,Ic,?z introduced a new type of Kantorovich type Bernstein‐Stancu operators ,and obtained a direct theorem about approximation .The present paper further generalized Ic,?z's results ,and established the direct and converse theorems about pointwise approximation .
For the increasingly powerful force in the media today ,the effects of television violence is widely discussed in various fields .Basing on the existing television violence study ,this paper adapts coding technology which is more advanced abroad to compile the first coding table about TV violence in Chinese version .And the samples of 376 hours of TV program from the CCTV and the local station TV are encoded by the coding table about TV violence to analyze the status of domestic violence in television .The results show that children’s programs contain large number of violence with high strength .The paper conducts an intervention on children’s aggression through the anti‐violence video ,and finds there is a quick effect on reducing children’s aggression just after a short term intervention . But the stable effect requires more long‐term intervention .
The secondary amine-functional polysiloxane is found to be efficient macromolecular ligand to accelerate copper(I)-catalyzed multicomponent cycloaddition of sodium azide,organic halide,and alkynes,in which the one-pot three-component click reaction can be performed smoothly with the mediation of secondary amine functional polysiloxane to give various 1,2,3-triazoles in moderate to good yields.
The dissociation chemistry of lithiated ions ,[M+ Li]+ ,of the main components (S3 ,S4 ,S5 and S6) in the silane coupling agent Si69 is investigated by electrospray ionization mass spectrometry .[M+Li]+ of these components is facile to undergo the cleavage of the C—S and the S—S bonds ,and the formed product ions are found to be solvated with the residual water in the vacuum system .In addition ,the loss of S2 is the main fragmentation pathway of [S5+Li]+ and [S6+Li]+ .
A ring Ris called a weakly J-clean ring if every element a∈Rcan be written in the form of a=e+j or a=-e+j where e is an idempotent and j belongs to the Jacobson radical.The paper explores various properties of weakly J-clean rings,proves that a ring Ris weakly J-clean if and only if Ris clean and R/J(R)is weakly Boolean,if and only if R/6Ris weakly J-clean and idempotents can lift J(R).A ring Ris uniquely weakly nil clean if and only if Ris abelian;J(R)is nil and Ris weakly J-clean.Each weakly J-clean ring Ris right(left)quasi-duo ring.Furthermore,the paper proves that the following are equivalent:Ris J-clean;there is an integer n≥1such that Tn(R)is J-clean;there is an integer n≥2such that Tn(R)is weakly J-clean;there is an integer n≥2such that×nRis weakly J-clean.
Using the classical algorithm for generalized variational inequalities , a class of generalized variational inequalities (GVIP) is studied in the Hilbert space ,the existence of solutions for GVIP is improved ,a new iterative algorithm is given ,simultaneously ,and a strong convergence theorem of the solutions for GVIP is obtained .
This paper analyzes the spatio-temporal pattern evolvement of Xixi wetland using high-resolution remote sensing images in 2000,2007 and 2012.The results show that the water area reduces obviously,where the river area reduces about 10%,reservoirs and ponds area is close to 50% reduction,and the area of vegetation also have different degrees of reduction.Urban construction land sharply instead of wetland,the area increases nearly 4times.Real estate development and road construction in the process of urbanization are the main motors of the wetland landscape pattern change.Finally,the Xixi wetland protection suggestions are proposed in the aspects of interference source control,defense and governance.
The existence of 2π‐periodic solutions for the third order differential equation x?(t)+ f (x′(t))+ h(x(t))x′(t)+β(t)g(x(t-τ(t)))= p(t) is explored by the variational methed ,a sufficient condition for the periodic solutions is obtained , and a relevant corollary is also provided .
A tetraethylenepentamine(TEPA)spacer arm was introduced between metal phthalocyanine and oxidized cellulose nanofibers for the preparation of spacer arm attached,CoPc functionalized nanofibers.The nanofibers were characterized by ATR-FTIR.The optimum immobilization condition was determined by single factor experimental method.The results showed that the immobilized metal phthalocyanine on the surface of nanofibers reached to 400μmol/g when NaIO4 concentration was 25mmol/L,oxidation temperature was 30°C,TEPA concentration was 10%,and glutaraldehyde concentration was 2%.With the introduction of spacer arm,the adsorption capacity of CoPc-s-NF to reactive red X-3Bdye was three times of that of metal phthalocyanine functionalized nanofibers(CoPc-NF)at pH 6.
In this paper ,a dual memristive chaotic circuit is presented .Its dimensionality reduction is studied ,and it is obtained that the dual memristive chaotic circuit of dimensionality reduction is consistent with the Chua's dual chaotic circuit . Then ,FPGA is used to implement this chaotic circuit ,and it expresses that the memristive chaotic circuits can be realized by digital way .
Polyvinylcholoride(PVC)was plasticized by epoxidized soybean oil instead of DOP,the change principles of the tensile fracture,dynamic mechanism and heat aging property of PVC were also investigated by regulating the dosage of ESO,and the properties of H-70 were compared.The results showed that when the dosage of ESO was 55,the tensile fracture was 17 MPa,the elongation at break was 382%,the glass transfer temperature was 28 ℃,the weight loss after heat aging was 2.56g/m2,which were significantly improved compared with H-70.
