共查询到20条相似文献,搜索用时 31 毫秒
1.
In this paper, double Λ binding energies B ΛΛ s of ΛΛ5He( ΛΛ5H), AA4He and ΛΛ4H are calculated with the help of few-body models. The results show that stable binding state for ΛΛ5H or ΛΛ5He exists definitely with B ΛΛ( ΛΛ5H)=6.75MeV and B ΛΛ( ΛΛ5He)=7.67MeV,respectively. As to ΛΛ4He and ΛΛ4H, preliminary results indicate that ΛΛ4H is unstable against decaying into Λ+ Λ3H, and ΛΛ4He has no binding state. 相似文献
2.
In this paper, using SU(6) symmetry theory four-baryon system is discussed and a method of analyzing experimental spectra is provided. Because of the gound states of ΛΛ4H, ΛΛ4He , Λ4He and 4He are in the same I. R. of SU(6), on can derives masses for ΛΛ4H, ΛΛ4He from the experimental data of Λ4H, Λ4He, and 4He. Calculation shows that these J π=0 + double Λ hypernuclei ΛΛ4H, ΛΛ4He are not likely bound states. 相似文献
3.
在室温下测量了GdoBr:Eu的常压和高压荧光谱,光谱范围在13 000~21 500 cm -1之间,压力至12 GPa。由光谱数据得到了Eu 3+晶场能级随压力的变化曲线。 7F 0~5能级随压力的变化规律比较复杂,而 5D 0~2各能均随压力的升高几乎线性地降低。在基态谱项 7F的49个状态上进行了晶场拟合计算,所得常压下的5个非零晶场参数分别为:B 02=-1 124.0 cm -1,B 04=-969.6 cm -1,B 44=827.9 cm -1,B 06=889.6 cm -1,B 46=377.0 cm -1。高压下的计算结果表明,B 04、B 06这两个晶场参数随压力的增加而增大,B 46随压力的增加而减小,而B 02、B 44随压力的变化有些起伏。晶场强度在8 GPa以下随压力增加而减小,其后开始变强。 相似文献
4.
Ca3Y2 (BO3)4:Eu^3+ phosphor is synthesized by high temperature solid-state reaction method, and the Iuminescence characteristics are investigated. The emission spectrum exhibits two strong red emissions at 613 and 621 nm corresponding to the electric dipole ^5 Do- ^7F2 transition of Eu^3+ under 365 nm excitation, the reason is that Eu^3+ substituting for Y^3+ occupies the non-centrosymmetric position in the crystal structure of Ca3 Y2 (BO3)4. The excitation spectrum for 613 nm indicates that the phosphor can be effectively excited by ultraviolet (UV) (254 nm, 365nm and 400nm) and blue (470nm) light. The effect of Eu^3+ concentration on the emission intensity of Ca3 Y2 (BO3)4 :Eu^3+ phosphor is measured, the result shows that the emission intensities increase with increasing Eu^3+ concentration, then decrease. The CIE colour coordinates of Ca3Y2 (BO3)4:Eu^3+ phosphor is (0.639, 0.357) at 15mol% Eu^3+. 相似文献
5.
采用异丙醇铝[Al(OC 3H 7) 3]为前驱体,溶胶-凝胶(Sol-gel)法制备Er 3+-Yb 3+共掺杂Al 2O 3粉末.实验结果表明:900 ℃烧结的粉末为固溶Er 3+、Yb 3+的γ-(Al,Er,Yb) 2O 3相和少量θ-(Al,Er,Yb) 2O 3相的混合物.Er 3+-Yb 3+共掺杂Al 2O 3粉末具有中心波长为1.533 μm的光致发光(PL)特性.1 mol % Er 3+和1 mol% Yb 3+共掺杂的Al 2O 3粉末的PL强度较1 mol % Er 3+掺杂提高2倍,半峰宽从53 nm增加到63 nm.随泵浦功率的提高,PL强度呈线性增加后渐呈饱和趋势. 相似文献
6.
Mixing between the 2 3S1 and 1 3D1 D s is studied within the 3P0 model. If mixing between these two 1 - states exists, D s1*(2700) ± and D sJ*(2860) ± could be interpreted as the two orthogonal mixed states with mixing angle θ≈ -80° in the case of a special β for each meson. However, in the case of a universal β for all mesons, D s1*(2700) ± could be interpreted as the mixed state of 2 3S1 and 1 3D1 with mixing angle 12° < θ < 21° but D sJ*(2860) ± seems difficult to interpret as the orthogonal partner of D s1*(2700) ±. 相似文献
7.
In the framework of quantum defect theory, we study super-excited states of F2 molecules which can dissociate into F^+ (^3P2,1,0) and F^-(^1 So) ion-pair. Based on our calculation, we present a vibrational resolved assignment of the high precision photofragment yield spectra for F^- from the F2 ion-pair production. 相似文献
8.
给出了函数的Hausdorff测度与H-导数。从而,为开展自给的分形动力学提供了解析的数学工具。同时,给出了分形动力学的演化方程组并做了初步讨论与分析。 相似文献
9.
The angular distributions of CO^+ from the dissociation of CO2^2+ and CO2^+ in intense femtosecond laser fields (45 fs, about 5 × 10^15 W/cm^2) are studied at a laser wavelength of 800nm based on the time-of-flight mass spectra of CO^+ fragment ions. The experimental results show that structural deformation occurs in the charge state of CO2^2+ and the CO^+ maintains linear geometrical structure. 相似文献
10.
We calculate the branching ratios of pure annihilation type decays B 0→D s- K 2*+ and B s→ Da 2 using the perturbative QCD approach based on kT factorization. The branching ratios are predicted to be (60.6 -16.5-10.4-2.1+17.3+4.3+3.2 )× 10 -6 for B 0→D s- K 2*+, (1.1 -0.4-0.2-0.1+0.4+0.1+0.1)×10 -6 for B s→ D0a 20 and (2.3 -0.8-0.4-0.1+0.8+0.2+0.1)×10 -6 for B s→D -a 2+. They are large enough to be measured in the ongoing experiment. Due to the shortage of contributions from penguin operators, there are no direct CP asymmetries for these decays in the Standard Model. We also derive simple relations among these decay channels to reduce theoretical uncertainties for the experiments to test the accuracy of theory and search of new physics signal. 相似文献
11.
In the framework of T2HDM, we calculated the new physics contributions involving neutral Higgs bosons to the branching ratios of B0s,d→l+l- (l=e, μ) decays. Comparing the theoretical predictions with the experimental upper-limits, we found that (a) The data of Br(B0d→l+l-) give the upper bound on tanβ: tanβ≤22, while Br(B0s→l+l-) give tanβ≤12 for fixed δ=0°, mH+=350 GeV, mH0=160 GeV, mh0=115 GeV and mA0=120 GeV; (b) A light neutral Higgs boson mass mh0 (mA0) less than 50 GeV (120 GeV) is excluded by the data of branching ratios for B0s,d→l+l-(l=μ) decays with tanβ=10; (c) The bounds on mh0 and tanβ, or mA0 and tanβ are strongly correlated: a smaller (larger) tanβ means a lighter (heavier) neutral Higgs boson. 相似文献
12.
在21 500~11 500 cm -1光谱区间内测量了Gd 2O 2S:Eu的荧光光谱,测量是在室温和液氮条件下进行的,对122条低温谱线和96条常温谱线进行了指认。识别了Eu 3+离子 5D 0~2及 7F 0~6的39个斯塔克能级中的35个能级。在0~15 GPa压力范围内,研究了Gd 2O 2S:Eu高压下的发射光谱。在压力作用下,发现所有观测到的谱线都红移,强度降低。6个 5D 0~2能级下降速度大于 7F J, 5D 2、 7F 2~5多重态的斯塔克劈裂变大,而 5D 1和 7F 1的劈裂变小。 相似文献
13.
Motivated by the rst measurement on B(B s→φμ +μ -) by the CDF Collaboration, we study the supersymmetric e ects in semi-leptonic B s→φμ +μ - decay. In our evaluations, we analyze the dependences of the dimuon invariant mass spectrum and the forward-backward asymmetry on relevant supersymmetric couplings in the MSSM with and without R-parity. The analyses show that the new experimental upper limits of B(B s→φμ +μ -)from the LHCb Collaboration could further improve the bounds on sneutrino exchange couplings and ( δLLu) 23 as well as ( δLL,RRu) 23 mass insertion couplings. In addition, within the allowed ranges of relevant couplings under the constraints from B(B s→φμ +μ -), B(B→K (*)μ +μ -) and (B s→φμ +μ -), the dimuon forward-backward asymmetry and the di erential dimuon forward-backward asymmetry of B s→φμ +μ -are highly sensitive to the squark exchange contribution and the ( δLLu) 23 mass insertion contribution. The results obtained in this work will be very useful in searching for supersymmetric signals at the LHC. 相似文献
14.
利用激光光解NO 2分子,通过共振增强多光子电离(REMPI resonance enhanced multiphoto ionization)及飞行时间(TOF time of flight)质谱技术,获得了振转态分辨的NO(X 2Π,υ″,J″)与自旋-轨道分辨的氧原子O(2P 3P J″=2,1,0)离子谱.NO分子与O原子的离子信号强度与UV电离激光能量之间的关系分别能用二次方和三次方曲线很好拟合,它表明:光解产物NO分子和氧原子是分别通过(1+1)和(2+1)多光子吸收过程而被电离的.由氧离子信号得到的氧原子基态三个自旋-轨道支能级布居比f 1与f 0分别为0.54±0.09和 0.20±0.04,这一比值与统计分布计算的值为0.6和0.2一致. 相似文献
15.
采用纳米管制备和离子掺杂同步进行的直接水热合成方法,合成了纯钛酸盐纳米管(TNT)和Eu 3+离子掺杂的纳米管(TNT-Eu);并利用X射线衍射(XRD)、透射电子显微镜(TEM)、光致发光谱仪研究了纳米管的形貌特征、物相组成、热稳定性和发光性能。结果显示:这种方法简便易行、稳定性好、产率高。钛酸盐纳米管物相可近似表示为(H,Na) 2Ti 3O 7或(H,Na) 2(Ti,Eu) 3O 7。高温处理对钛酸盐纳米管的结构产生很大的影响,450 ℃下纳米管的层状结构被破坏,晶体结构转化为锐钛矿型的TiO 2。TNT-Eu样品的发光性能较强,出现的393.5 nm、593 nm、614 nm的谱带归属于 5D 0- 7F 1和 5D 0- 7F 2电子的跃迁。 相似文献
16.
The coupling problem of the three different intermediate processes J/ψ→ωf 2(1270),f 2→π +π - and J/ψ→b 1±(1235)π +,b 1±→ωπ ± included in the hadronic decay process J/ψ→ωπ +π - is discussed.The consideration of the coupling effect is very important for measuring the parameters of the resonances f 2 and b 1± and the helicity amplitude ratios of these reactions precisely. 相似文献
17.
We investigate the luminescence properties of Bi^3+ and RE^3+ (RE = Tb or Eu) in a Y3Ga5O12 (YGG) host system. The additional doping of Bi^3+ can enhance the luminescence of Th^3+ or Eu^3+ in this host. Energy transfer from Bi^3+ to Tb^3+ and Eu^3+ is observed and the mechanism of energy transfer is investigated. Mechanism of energy transfer can be explained as electric multipole interaction since the Bi^3+ emission band and Tb^3+ or Eu^3+ excitation band overlaps and the Bi^3+ emission intensity decreases while the intensity of Tb^3+ or Eu^3+ increases with the increase of Tb^3+ or Eu^3+ concentration. Therefore, Bi^3+ ion is a kind of efficient sensitizer to the Tb^3+ and Eu^3+ activators in the Y3Ga5O12 host. 相似文献
18.
采用飞片碰撞技术,在TNT/RDX(40/60)炸药中获得了2.5倍于正常爆轰的最大超压值,得到了超压爆轰下爆轰产物物态方程p=Aρ k+A1(p-pJ)(p-爆压,单位GPa,ρ-密度,单位kg/m 3,A=ρ J/ρ kJ,p J=27.06 GPa,ρ J=2.3×10 3 kg/m 3,k=2.77,A 1=2.7×10 -3 GPa -1,下表J代表正常爆轰状态)。该方程还可以较好地描述超压爆轰产物的二次冲击状态。 相似文献
19.
In this paper we disscuse disscuse the physicsical aspect of cross-section differences Δ ABcγ= dσ( AB→ cγX)- dσ( AB→ cγX) and give the simple rules to select the elementary subprocesses which contribute to cross-section differences. We bind a way to test the gluon distribution functions of hadrons through the measurement of cross-section difference or combination of cross-section differences in the large P T process with direct photon emission. Moreover we obtain simple relations between each combination of cross-sections and the corresponding gluon distribution functions of proton, neutron, pion and daon: G p8(x)/(Δ pphγ-Δ pphγ)=G n8(x)/(Δ pphγ)=G π8(x)/(Δ π+phγ+Δ π-phγ=G K8(x)/(Δ K+phγ+Δ K-phγ)which are expected to be test in experiment. 相似文献
20.
采用压力光谱技术在低温下观测到了Mn 2+离子的 4T 1→ 6A 1跃迁,该谱线在Zn 0.83Mn 0.17Se和ZnSe/Zn 0.84Mn 0.16Se超晶格样品中有不同的压力行为,体材料中其压力系数为-42.4 peV/Pa,超晶格中为-29.5 peV/Pa。用晶体场理论计算得到体材料Zn 0.83Mn 0.17Se中Mn 2+离子 4T 1→ 6A 1谱线的压力系数为-38.3 peV/Pa,与实验结果基本一致。结合材料中发光峰积分强度随压力的变化关系进行分析,证实Mn 2+离子的发光性质主要与其近邻的晶体场环境有关。 相似文献
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