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1.
考虑四夸克态是双夸克和双反夸克的束缚态, 在一相对论夸克模型下利用变分法计算了轻重四夸克态的质量. 采纳夸克-夸克及双夸克-双反夸克之间的相互作用为单胶子交换势与标量和矢量线性禁闭混合势的总和, 使用拟合基态介子质量得到的参数作为输入, 计算了0++的轻、重四夸克态的质量. 计算的结果支持X(3872), Y(3940)是含有粲夸克的0++重四夸克态;f0(600), κ(800), f0(980)和a0(980)是0++的轻四夸克态.  相似文献   

2.
在FOCK空间建立了一类新的非线性相干态.采用数值计算方法,对其压缩和反聚束等量子统计特性进行了研究.这些结果表明,在|α|范围内,这种新型的奇偶相干态在X2方向出现了压缩效应和反聚束效应.
Abstract:
In the paper, a new kind of even and odd nonlinear coherent states is constructed in the Fock space. Using numerical method, their quantum statistical properties such as amplitude-squeezing and anti-bunching are investiga-ted. The results show that in the range of |α|, amplitude-squeezing effect and anti-bunching effect appear in thedirection X2 in the new kind of even and odd coherent states.  相似文献   

3.
Turpan is one of the major high-quality grape production bases in the world for years because its climate is so special (hot, dry, and windy). The grape market needs the varieties with high yield, quality, and environmental adaptability. ‘Xinyu’ is a new variety bred by crossing selection of E42-6 (a self-pollinated inbred of Vitis vinifera cv. ‘Red Globe’) as female and Vitis vinifera cv. ‘Rizamat’ as male parents and registered in the Crop Varieties Registered Commission of Xinjiang Uygur Autonomous Region in 2005. In this study, we determined the impacts of environmental factors on its photosynthesis. The results showed the climate in Turpan was characterized by long-time intensive sunshine, high temperature and relatively low humidity. The peak value of photosynthetic available radiation (PARi) was 1 454 μmol·m-2·s-1, and the minimum and average values were 111 μmol·m-2·s-1and 938.889 6 μmol·m-2·s-1, respectively. Air temperature and sunlight intensity reached the highest values during 1 p.m. to 4 p.m. Net photosynthetic rate (Pn) of Xinyu increased stably before 11 a.m. and there was a midday depression during 11 a.m. to 2 p.m. The minimum value of Pn appeared at noon (2.77 μmol·m-2·s-1). It was concluded that as a new grape cultivar, “Xinyu” could withstand extreme climate conditions in Turpan.  相似文献   

4.
考虑四夸克态是双夸克和双反夸克的束缚态,在—相对论夸克模型下利用变分法计算了轻重四夸克态的质量.采纳夸克-夸克及双夸克-双反夸克之间的相互作用为单胶子交换势与标量和矢量线性禁闭混合势的总和,使用拟合基态介子质量得到的参数作为输入,计算了0^++的轻、重四夸克态的质量.计算的结果支持X(3872),Y(3940)是含有粲夸克的0^++重四夸克态;fo(600),x(800),fo(980)和ao(980)是0^++的轻四夸克态.  相似文献   

5.
运用包括非迭代三激发电子相关耦合簇CCSD(T)方法和Dunning等人使用的相关一致aug-CC-PVxZ(x=D,T,Q,5)自洽基组对XF(X=H,D,T)分子进行了结构优化,优化值然后被插值到CBS极限.结果表明随着x的增大aug-CC-PVxZ系列基组优化的结构逼近实验值,计算频率与实验值最大差距不足1%,最小仅为0.099%,平衡间距最大只有0.8%的差距.通过计算还表明:在结构优化和频率分析时CCSD(T)显示出优秀的特性,但在研究与边界态或解离有关的问题时,CCSD(T)不能给出良好的结果,相反CCSD方法却能给出合理的解离极限.最后我们研究了XF(X=H,D,T)的分子势能函数和光谱常数,理论结果与已知实验值吻合的非常好.首次获得了XF(X=H,D,T)系列分子的ω_ey_e,ω_eZ_e,β,γ,H_e,F_e值.
Abstract:
The equilibrium structure and vibrational frequency of FX(X=H,D,T)molecules are calculated at the CCSD(T)level in conjunction with serials of basis sets aug-CC-PVxZ(x=D,T,Q,5),and then the optimized values are extrapolated to CBS limitation.The theoretical results are shown to be in greater agreement with the experiments as x increases.The difference is only 1%between experiments and the Dresent calculation in vibrational frequency and the maximum equilibrium nuclear distance is 0.8%.Calculations indicate that CCSD(T)is the best method in the optimization and frequency analysis but it cannot give a correct limitation in the study of dissociation process whereas CCSD can solve this question and give a reasonable dissociation limitation.The analytic potential energy function of FX(X=H,D,T)is derived by least square fitting to Murrell-Sorbie and Dunham function,and the force constants and molecular constants are obtained.The results in this study are in good agreement with the experiment data.The ω_ey_e,ω_eZ_e,β,γ,H_e,F_e values are obtained for the first time.  相似文献   

6.
The article reports a method of making dried larval specimens of Erythraeidae,ectoparasitism of insect,refreshed for taxonomic study.The dried larvae are let in cuvettes with 50%ethanol.The cuvette plat is then put into a beaker with water in appropriate amount,fulling to 1/3-2/3 high of the cuvette plat.The beaker is heated until the water boiling,and then stop to heat.After that,the treated larvae are immersed into a container with ethanol-glycerol solution(50%ethanol:glycerol=20:1),and then the container is warmed in a Water-Bath at 60℃for 2h to‘refresh’the larvae.The refreshed larvae are as mollescent as fresh ones and easy to be prepared for morphologic observation and long-term preservation.  相似文献   

7.
A robust repetitive control scheme is used to improve the rate smoothness of a brushless DC motor (BLDCM) driven test turntable. The method synthesizes variable structure control (VSC) laws and repetitive control (RC) laws in a complementary manner. The VSC strategy can stabilize the system and suppress uncertainties, such as the aperiodic disturbance and noises, while RC strategy can eliminate the periodic rate fluctuation in a steady state. The convergence of the repetitive learning process is also guaranteed by VSC. A general nonlinear system model is discussed. The model can be considered as an extension of BLDCMs. The stability and asymptotic position tracking performance are validated by using Lyapunov functions. Simulation results show the effectiveness of the proposed approach for improving the rate smoothness.  相似文献   

8.
Mycoplasma mycoides subsp mycoides SC (MmmSC) is the etiological agent of contagious bovine pleuropneumonia (CBPP). The lipoprotein LppQ encoded by lppQ gene is specific to MmmSC and is found in the type strain and in field strains isolated in Europe, Africa, and Australia, as well as in vaccine strains. No serological cross-reactions were observed with the related mycoplasmas of the Mycoplasma mycoides cluster. The N-terminal domain of the mature lipoprotein LppQ is hydrophilic, and it induces a strong, specific, early, and persistent immune response in naturally and experimentally infected animals. Mycoplasma-specific TGA (Trp) codons are utilized as stop codons in most other organisms. The lppQ N-terminal fragment from MmmSC HVRI X strain, the Chinese strain for CF antigen production, was mutated with one-step overlapping extension PCR. Sequence analysis confirmed the successful mutation from A to G in codon 198 in the lppQ gene. The fragment containing the mutation site was subcloned into the pET32a expression vector. The recombinant protein with molecular weight of 42 kDa was purified using the Ni-NTA His.Bind purification kit, with a purity of up to 95%. Western blot indicated that the standard positive serum of CBPP could react with the recombinant protein. The purified protein was diluted to 0.35 μg mL^-1, and coated to microtiter enzyme-linked immunosorbent assay (ELISA) plates. Indirect ELISA reaction conditions were optimized. The value of P/N was determined to be 4.8 (0.934/0.193), the sensitivity to be 95.8% (46/48), and the specificity to be 98.9% (161/163). 3 817 cattle serum samples from three different provinces were detected by the indirect ELISA and CFT. The Kappa value is 0.63, which is middle or high agreement between the two methods.  相似文献   

9.
首先从热力学角度阐述了系统内能的本质涵义;进一步又对自引力系统(尤其是球对称自引力系统)阐明了自引力系统内能的涵义;最后又以球对称自引力系统为例具体地分析了自引力系统熵的演化取决于系统内能所处的能态,当系统的能态为正能态时,系统的熵按熵增原理演化,反之,当系统的内能处于负能态时,系统的熵必然按熵减原理演化.
Abstract:
In this paper,the meaning of the internal energy of a system is expounded from the perspective of thermodynamics,and then the meaning of the internal energy of a self-gravitational system,particularly,a spherical symmetric self-gravitational system,is demonstrated.Finally,the spherical symmetric selfgravitational system is taken as an example to illustrate that the evolution of entropy of a self-gravitational system is determined by the energy state(or the energy spectrum)of the system.If the system is in the positive energy state,its evolution will follow the principle of entropy increase.Conversely,if the system is in the negative energy state,its evolution will follow the principle of entropy decrease.  相似文献   

10.
The determination method of Schisandrin A and Schisandrin B in Schisandra chinensis was improved with the high performance liquid chromagraphy(HPLC).The sample was extracted exceedingly in the critical limit of CO 2 .The retention time of Schisandrin A and Schisandrin B was reduced,with methano/water(75:25)as mobile phase.The wavelength for detection was 254 nm. The R2 of standard curve was 0.9998 and the relative standard deviation was 2.31%and 3.17%with the recovery of 96.45%and 97.37%,respectively.The result shows that the rate of veracity of this method is higher and it proves that the determination method of Schisandrin A and Schisandrin B in Schisandra chinensis is a feasible method.  相似文献   

11.
《河北农业大学学报》创刊年代考   总被引:3,自引:0,他引:3  
清光绪二十八年(1902)河北农业大学前身—直隶农务学堂诞生,经几易其名,于1958年更名为河北农业大学至今。清光绪三十一年(1905)直隶高等农业学堂时期创办了《北直农话报》,清光绪三十四年(1908)更名为《直隶农务官报》,中华民国七年(1918)改出《农学月刊》,中华民国十七年(1928)易名为《河大农刊》,中华民国二十三年(1934)更名为《河北通俗农刊》,中华民国二十四年(1935)易名为《河北农林学刊》,1948年更名为《河北农学院研究专刊》,1959年更名为《河北农业大学学报》至今。《河北农业大学学报》前身诸刊都与现时的《河北农业大学学报》有着一脉相承的历史渊源,各刊之间联系紧密,连续性、继承性强。因此,《河北农业大学学报》的创刊时间应追溯至1905年创办的《北直农话报》。  相似文献   

12.
为探明客源市场生态旅游消费的潜在特征,采用问卷调查的形式,就长沙市居民对湖南金洞生态旅游开发的意向等问题进行抽样调查.结果显示,生态旅游符合人们“回归自然”的旅游新时尚,有着极大的开发空间,指出生态旅游的开发要注重环境保护和可持续发展.开发的产品要以休闲度假类的大众产品为主,开发生态旅游都市客源市场还要多种渠道并用,尤其是要注重媒体的宣传.  相似文献   

13.
饲料中有效能是供动物生长发育的基础.不同动物所用的有效能体系不同,目前大多数动物采用消化能、代谢能体系,但随着研究的发展与深入,发现最能反映饲料有效能的是净能体系.无论哪种体系,采用合理的测定技术准确测定饲料中的有效能值显得尤其重要,通过对饲料有效能值的准确测定可以实现动物所需能量的精确供给,减少养殖成本,使经济效益最大化.文章综述了几种有效能评价体系的测定技术.  相似文献   

14.
国家贫困生资助政策实施以来,对贫困生帮助很大,同时在实际运行中还存在着一些问题。本文提出贫困生认定工作仍需要进一步采取各种相关配套措施,以推动和保障贫困生资助工作更好地开展。  相似文献   

15.
应用萄聚糖凝胶柱层析对水牛梭形住肉孢子虫包囊包溶性抗原进行了纯化。结果表明:纯化水牛梭形住肉孢子虫包囊抗原的最适条件为:选用萄聚糖凝胶G—100柱层析系统;洗脱液为03MPBS(pH72),床体积为10cm×165cm,上样体积为500HL;流速为12mL/h。纯化抗原可使琼脂凝胶双扩散试验的阳性检出率提高30%。  相似文献   

16.
[目的]通过体外抗氧化体系比较黑豆不同部分馏油抗氧化性活性。[方法]通过正交试验优化索氏提取黑豆馏油的最佳工艺,提取黑豆不同部分馏油;研究黑豆不同部分馏油对羟基自由基(·OH)、DPPH自由基(DPPH·)的清除能力。[结果]在样品浓度为1.0 mg/mL时,黑豆不同部分馏油对·OH的清除率分别为全豆馏油83.9%、豆黄(黑豆去皮部分)馏油64.8%、豆皮馏油17.3%,对DPPH·的清除率分别为全豆馏油41.3%、豆黄馏油33.2%、豆皮馏油77.9%。[结论]黑豆不同部分馏油均具有较好的抗氧化性,是良好的天然抗氧化剂。黑豆不同部分馏油对·OH的清除能力从大到小依次为全豆馏油、豆黄馏油、豆皮馏油,对DPPH·的清除能力从大到小依次为豆皮馏油、全豆馏油、豆黄馏油。  相似文献   

17.
采用L(934)正交设计试验,对山茱萸浸提液中山茱萸多糖的酶水解法提取工艺进行了优化研究,并对浸提液的中有效成分马钱苷含量进行了HPLC法分析。结果表明,山茱萸多糖浸提的最佳工艺为:液料比1∶5,浸提时间4 h,浸提温度80℃,果胶酶添加量0.55 g/L。用HPLC法测定出的山茱萸浸提液中马钱苷平均含量为0.512 ...  相似文献   

18.
板栗属壳斗科栗属(Castanea mollisima Blume),其种子属于顽拗型种子,不耐贮藏。基于近年来板栗贮藏保鲜技术研究成果,从合理采收、贮前处理、贮藏方法等方面进行论述。  相似文献   

19.
为了预测厚胶合板弹性模量,通过简化层合板理论,该文建立了胶合板弹性模量预测模型,并以单板条、经过涂胶热压处理的单板条和相同工艺条件下的单板层积材的弹性模量,采用4种不同铺层方式的19层桉树胶合板对模型进行了验证。结果表明:3种预测值与实测值的趋势一致,相关系数R2顺纹在0.86以上,横纹在0.88以上,但是精度不同。采用单板条弹性模量预测的胶合板弹性模量比实测值偏低;采用经过涂胶热压处理后的单板条弹性模量预测的胶合板弹性模量比实测值偏高;采用相同工艺条件下的单板层积材弹性模量预测的胶合板弹性模量与实测值偏差较小,顺纹平均误差为4.64%,横纹平均误差10.94%。因此,采用相同工艺条件下的单板层积材的弹性模量来预测胶合板的弹性模量是可行的。   相似文献   

20.
赵经华  张春姹 《安徽农业科学》2006,34(17):4480-4481
分析了入世4年来,我国水果出口在量上实现了突破,但并没有实现质变的主要原因,指出我国水果业存在的问题。论述了引进外资对发展我国水果业的意义,并提出了具体可行的对策与建议。  相似文献   

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