排序方式: 共有47条查询结果,搜索用时 15 毫秒
1.
判别分析在食物四性量化标准研究中的应用 总被引:2,自引:0,他引:2
在中医营养学中,食物的四性是指食物的寒、热、温、凉四种不同的性质,它是古人根据食物作用于人体所发生的不同反应与获得的不同疗效而概括、归纳、总结出来的食物特性,所谓“寒者热之,热者寒之,温者清之,凉者温之”以及药膳中“以寒凉食物清热滋阴,以温热食物散寒通阳”等,这些都是中医学理论治病用药之大法,同时也是人们选择食物、摄取营养的重要原则。数千年来,食物的四性一直作为指导中药药膳、解释食疗作用机理的主要依据。然而,到目前为止,食物四性的划分除按照人们的经验与感官外,还没有一种相对科学的判定理论和方法,致使不少食物的性、味至今说法不一,甚至相互矛盾。因此,有必要用现代科学的方法对食物的四性判定进行一些量化方面的研究,从而为其四性的划分提供一些客观依据。 相似文献
2.
采用电感耦合等离子体质谱法测定了纺织品中的可萃取As。采用反应模式以去除40Ar35Cl+离子对测定75As+的干扰,标准工作曲线采用基体匹配的方法减少基体效应的影响。样品采用模拟酸性汗液进行萃取,将萃取液稀释5倍后进行测定,以降低盐分对仪器的影响。方法检出限为6μg/kg,测定低限2μg/kg,在样品中添加0.02~0.2 mg/kg的砷时,回收率97.8%~98.6%,相对标准偏差小于5%。方法满足了检测生态纺织品(婴幼儿产品)的限量要求。 相似文献
3.
4.
5.
Three new cadmium or zinc arenedisulfonate complexes [Zn(bpp)2(L)]n 1, { [Cd(bpp)2(1,5-NDS)(H2O)2]·4H2O }n 2 and { [Cd(bpp)2(H2O2)2]·(1,5-NDS) } n 3 (L = 4,4′-bis(2-sulfonatostyryl)biphenyl, bpp = 1,3-di(4-pyd-dyl)propane and 1,5-NDS = 1,5-Naphthalenedisulfonate) have been synthesized from aqueous solution and structurally characterized by infrared spectroscopy, elemental analysis and single-crystal X-ray diffraction. Crystal data for complex 1: space group P21/n, a = 10.559(3), b = 13.138(4), c = 17.623(5)A^°, β = 100.852(3)°, V = 2400.9(12) A^°^3 Z = 2, Dc= 1.351 g/cm^3, F(000) = 1016, μ = 0.654 mm^-1, the final R = 0.0412 and wR = 0.0994; Crystal data for complex 2: space group P^-1, a = 8.5642(19), b = 10.076(3), c = 12.114(3) A^°, α = 81.623(7), β = 77.149(8), γ = 82.787(7)°, V = 1003.6(4) A^°^3 Z = 1, Dc= 1.495 g/cm^3, F(000) = 466,μ = 0.713 mm^3, the final R = 0.0241 and wR = 0.0713; Crystal data for complex 3: space group C2/c, a = 21.6024(15), b = 9.4608(5), c = 18.4656(11)A^°, β = 107.359(3)°, V= 3602.0(4)A^°^3 Z = 4, Dc= 1.533 g/cm^3, F(000) = 1704,μ = 0.780 mm^-1, the final R = 0.0229 and wR = 0.0572. The X-ray single diffraction reveals that 1 exhibits a 3D metal-organic framework formed from 2D Zn(bpp)2^2+ networks connected by L in the third dimension; 2 and 3 possess 3D and 2D architectures constructed from 1D polymeric chains through H-bond. Complexes 1-3 display photoluminescent emissions at 452 and 335 nm, respectively. 相似文献
6.
In this paper a singularly perturbed linear second order hyperbolic problem with zerothorder reduced equation is discussed.Firstly,an energy inequality of the solution and anestimate of the remainder term of the asymptotic solution are given.Then an exponentiallyfitted difference scheme is developed in an equidistant mesh.Finally,uniform convergencein small parameter is proved in the sense of discrete energy norm. 相似文献
7.
8.
In this paper we consider a quasilinear second order ordinary differential equation equation witha small parameter e.Firstly an approximate problem is constructed.Then an iterativeprocedure is developed.Finally we give an algorithm whose accuracy is good for arbitraryε>0. 相似文献
9.
10.
本文讨论带有关于x的一阶导数项的双曲奇异摄动初边值问题,在较弱的相容性条件下构造了问题的渐近解并证明了解的一致有效性.然后我们对原问题构造一个指数型拟合差分格式并建立了离散能量不等式.最后我们证明差分问题的解一致收敛于原问题的精确解. 相似文献