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1.
原子吸收光谱法测定大学生膳食中锌   总被引:1,自引:1,他引:0  
微量元素锌对人体健康的影响已引起了广泛关注。对大学生锌饮食状况进行了调查,采用原子吸收光谱法分析大学生的锌膳食营养状况。结果表明,大学生从膳食中摄取的锌较为缺乏,食物中微量元素锌在不同类食物中含量差别较大,即使同一类食物原料中Zn元素在不同制作产品中含量差别也较大。因此,必须重视大学生的膳食营养状况,饮食中需注意合理调配,平衡膳食。  相似文献   

2.
本文对大学生饮食状况进行了调查,并采用石墨炉原子吸收光谱法测定大学生膳食中的Se、Mo、Ge、V等元素,结果表明大学生从膳食中摄取的Se、Mo元素充足,但Ge,V较为缺乏。由测试结果可知食物中元素含量存在着明显地区差,微量元素Se、Mo、Ge、V在不同类型的食物中含量差别较大。  相似文献   

3.
采用乳酸菌发酵结合动态高压微射流(Dynamic High Pressure Microfluidization,DHPM)技术,对豆渣进行改性,探讨其对膳食纤维组成、水化性质、持油力、胆汁酸结合能力及阳离子交换能力的影响。结果表明:乳酸菌发酵和DHPM均可有效提高豆渣中可溶性膳食纤维的含量,并降低不可溶性膳食纤维的含量,使可溶性与不可溶性膳食纤维含量的比值最大达到1∶2.6;乳酸菌发酵和DHPM能明显改善膳食纤维的水化性质和持油力,但对阳离子交换能力的影响不显著;乳酸菌发酵使豆渣膳食纤维结合胆汁酸的能力下降,而DHPM则使之升高。乳酸菌发酵和DHPM可以作为提高膳食纤维生理功能的有效途径。  相似文献   

4.
用于中温烟气脱硫的新型钙基脱硫剂   总被引:5,自引:1,他引:4  
研究了高效钙基脱硫剂的制备原理,在石灰水合反应生成氢氧化钙和提高比表面积两个关键环节上,采用了一系列方法提高钙利用率,获得突破性进展。进一步研究了中温范围内脱硫温度对钙利用率的影响,得到700℃时超过95%的钙利用率,为发展中温干式烟气脱硫工艺开辟了新的道路。  相似文献   

5.
原子吸收法测定磷矿和肥料中的钙和镁   总被引:1,自引:1,他引:0  
肥料及肥料原料中含有的钙和镁是植物主要的营养成份,在植物体内碳水化合物的代谢过程中起着重要的作用。本文用原子吸收方法对磷矿及各种肥料中钙和镁的测定。并探讨了磷矿及肥料中共存元素对测定钙、镁的干扰及消除。  相似文献   

6.
利用石墨炉原子吸收分光光度计对两种葡萄糖酸钙口服液中的钙进行了检测,分析了口服液中钙的含量。该方法准确便捷,为特定溶液样品中各种微量元素的检测提供了一条很好的途径。  相似文献   

7.
木耳膳食纤维营养成分测定和结构表征   总被引:1,自引:0,他引:1  
电感耦合高频等离子体发射光谱法测定木耳膳食纤维多种微量元素的方法。采用湿法酸消解制备样品,硝酸∶高氯酸(10∶1),120℃恒温消化溶解,酸度控制10%,满足ICP-AES测定的要求。经检测国家标准物质GBW07602验证,方法的准确度在1.12%~6.15%之间,精密度在0.41%~5.69%之间。实验数据表明,该方法是木耳中微量元素检测简便有效的方法。同时应用扫描电子显微镜进行木耳膳食纤维表面结构测定,并采用化学分析方法测定木耳膳食纤维中蛋白质、粗脂肪、粗纤维及水分的含量,其相关性研究为木耳膳食纤维开发利用提供了新途径。  相似文献   

8.
高钙飞灰的矿物学组成及微区特征研究   总被引:1,自引:0,他引:1  
对小龙潭电厂飞灰及不同密度级的分选灰的矿物学和颗粒微区特征进行了详细研究,高钙飞灰中的含钙矿物主要包括石灰,硬石膏,钙黄长石,镁黄长石和氢氧钙石;同时含有少量斜硅钙石,方解石,钙铁石,陨硫钙石,钙铁榴石和钙铝榴石;不同密度级分选灰矿物组成和微区特征差异很大.石英、莫来石主要存在于低密度级飞灰;石灰、硬石膏在漂珠中明显富集;斜硅钙石和钙铝榴石主要存在于沉珠中;含铁矿物赤铁矿,磁铁矿以及钙铁石在重灰和沉珠中的含量明显高于漂珠和轻质灰.  相似文献   

9.
评价南方膳食结构中铁的吸收率,为我国不同人群、不同膳食类型的铁吸收率提供参考资料。采用~(57)Fe-EDTA或~(57)FeSO4两种铁的稳定性同位素示踪方法,以稀土元素Dy作为排泄物的回收标记物,于现场进行人体代谢试验,受试者为健康成年男子和孕龄妇女各10名,分6次口服3.0mg的~(57)Fe稳定性同位素示踪剂及2.0mg的Dy,粪便监测法收集同位素排出粪样;用电感耦合等离子体质谱仪测定粪样~(57)Fe/~(56)Fe的比值,用原子吸收光谱法测定粪样总Fe,从而计算该人群膳食铁的吸收率。在南方膳食结构中,口服~(57)Fe-EDTA示踪剂,成年男子膳食铁的吸收率为7.34%,孕龄妇女的吸收率为6.92%;口服~(57)Fe-SO4示踪剂,成年男子膳食铁的吸收率为6.01%,孕龄妇女的吸收率为5.40%。本研究结果表明口服~(57)Fe-EDTA评价膳食铁吸收率虽有高于用~(57)FeSO4评价结果的趋势,但无显著性统计分析差异。中国南方城市膳食中铁的吸收率与2000年中国营养学会对我国居民膳食铁吸收率的估计水平大致相当。  相似文献   

10.
钙元素含量直接影响牛奶的品质,牛奶作为人体摄入钙营养素的一种重要食品来源,其钙含量分析样品量巨大,传统基于消解、灰化等复杂前处理的实验室方法分析效率较低,因此迫切需要建立牛奶中钙含量的快速及现场分析方法。近年来,液体阴极辉光放电-原子发射光谱(SCGD-AES)因无需真空条件和燃气、载气等附加气体而受到关注。自主开发了一套采用CCD检测器的便携式液体阴极辉光放电-原子发射光谱仪,采用牛奶样品直接稀释进样,考察了该仪器对牛奶中钙含量分析的适用性,建立了稀酸稀释进样-大气压液体阴极辉光放电-原子发射光谱法快速测定牛奶中钙含量的分析方法。对该法测定牛奶中钙含量的主要工作条件与参数进行了优化,结果表明:酸度对钙元素测定灵敏度的影响显著,采用1%(V/V)硝酸介质,该方法对钙元素测定具有最佳的灵敏度和稳定性。该方法将1%(V/V)硝酸作为牛奶样品的稀释液。系统考察了稀释倍数对牛奶样品中钙含量测定的影响,结果表明:采用100倍以上1%(V/V)稀硝酸稀释,牛奶中钙含量的测定准确度良好,未发现显著的基体干扰。将该方法应用于实际牛奶样品中钙含量的测定,稀释倍数选取100倍时,方法检出限为35 mg·L-1,牛奶样品中钙含量能够准确测定的同时,无需进一步稀释;加标回收率在89.0%~109.7%之间;对同一牛奶样品中钙含量6次重复测试的相对标准偏差低于5%,且单一样品测试时间小于1 min。结果表明:该方法可以满足牛奶中钙含量的实验室快速测定和现场快速分析或筛查要求。  相似文献   

11.
Based on clinical trials showing the efficacy to reduce vertebral and non‐vertebral fractures, strontium ranelate (SrR) has been approved in several countries for the treatment of postmenopausal osteoporosis. Hence, it is of special clinical interest to elucidate how the Sr uptake is influenced by dietary Ca deficiency as well as by the formula of Sr administration, SrR versus strontium chloride (SrCl2). Three‐month‐old ovariectomized rats were treated for 90 days with doses of 25 mg kg?1 d?1 and 150 mg kg?1 d?1 of SrR or SrCl2 at low (0.1% Ca) or normal (1.19% Ca) Ca diet. Vertebral bone tissue was analysed by confocal synchrotron‐radiation‐induced micro X‐ray fluorescence and by backscattered electron imaging. Principal component analysis and k‐means clustering of the acquired elemental maps of Ca and Sr revealed that the newly formed bone exhibited the highest Sr fractions and that low Ca diet increased the Sr uptake by a factor of three to four. Furthermore, Sr uptake in bone of the SrCl2‐treated animals was generally lower compared with SrR. The study clearly shows that inadequate nutritional calcium intake significantly increases uptake of Sr in serum as well as in trabecular bone matrix. This indicates that nutritional calcium intake as well as serum Ca levels are important regulators of any Sr treatment.  相似文献   

12.
基于钙内标的贝壳元素成分微区LIBS分析方法研究   总被引:1,自引:0,他引:1  
贝类生物作为海洋生态系统监测的理想标识,以Xa为内标进行元素比例变化的分析,将有可能获知气候演化及贝类生长等有用信息。区别于其他技术,微区激光诱导击穿光谱技术(Micro—LIBS:micro—probe laser induced breakdown spectroscopy)应用于贝类贝壳探测时,Ca的特征发射谱线将分布于整个光谱探测区间,如何选择合适谱线作为内标是Ca内标法用于贝壳成分元素分析的关键。以Xa元素为内标进行贝壳成分元素的Micro-LIBS探测,通过归一化Ca元素全谱谱线、最强离子谱线CaⅡ393.3 nm和不同强度原子谱线(XaⅠ422.7nm/XaⅠ487.9 nm)为内标情况下Sr/Xa元素比例变化的比较,结果发现相较于Xa离子线XaⅡ393.3 nrn和强度较弱原子线CaⅠ487.9 nm,以Ca元素全谱强度或最强原子线XaⅠ422.7 nm为内标时,Sr/Ca分布在贝壳分析区域内变化较小,其浮动分别小于7%和10%,符合贝壳分析区域为同一生长周期的纹理特征,较为准确地反映了贝壳的生长发展;同时,应用Ca全谱强度为内标对贝壳成分元素分析发现,元素比例Li/Xa,K/Xa,Na/Ca相较于Mn/Ca,具有明显的相似特征,说明海水富含轻质元素在贝壳生长分布上具有明显的相似性。研究结果表明,较强Ca原子线或全谱强度比Ca离子线更适合作为内标用于贝壳成分元素的微区LIBS分析,证明了Micro—LIBS用于贝壳分析的可行性。  相似文献   

13.
磁流化床强化烟气脱硫反应机理研究   总被引:1,自引:2,他引:1  
磁流化床对脱硫反应的强化作用分铁磁颗粒强化和磁场强化两方面.铁磁颗粒强化体现在铁磁颗粒对SO2脱除具有催化氧化作用;磁场强化,体现在磁场能增强Ca(OH)2的溶解度,从而增强Ca(OH)2浆滴的脱硫能力.磁流化床烟气脱硫的试验研究结果证实了上述分析的正确性.  相似文献   

14.
In order to investigate fractionation of calcium (Ca) isotopes in vertebrates as a diagnostic tool to detect Ca metabolism dysfunction we analyzed the Ca isotopic composition (δ44/40Ca?=?[(44Ca/40Ca)sample/(44Ca/40Ca)reference]?1) of diet, faeces, blood, bones and urine from Göttingen minipigs, an animal model for human physiology. Samples of three groups were investigated: 1. control group (Con), 2. group with glucocorticosteroid induced osteoporosis (GIO) and 3. group with Ca and vitamin D deficiency induced osteomalacia (?CaD). In contrast to Con and GIO whose average δ44/40Cafaeces values (0.39?±?0.13‰ and 0.28?±?0.08‰, respectively) tend to be lower than their diet (0.47?±?0.02‰), δ44/40Cafaeces of ?CaD (?0.27?±?0.21‰) was significantly lower than their δ44/40Cadiet (0.37?±?0.03‰), but also lower than δ44/40Cafaeces of Con and GIO. We suggest that the low δ44/40Cafaeces of ?CaD might be due to the contribution of isotopically light Ca from gastrointestinal fluids during gut passage. Assuming that this endogenous Ca source is a common physiologic feature, a fractionation during Ca absorption is also required for explaining δ44/40Cafaeces of Con and GIO. The δ44/40Caurine of all groups are high (>2.0‰) reflecting preferential renal reabsorption of light Ca isotopes. In Göttingen minipigs we found a Ca isotope fractionation between blood and bones (Δ44/40Cablood-bone) of 0.68?±?0.15‰.  相似文献   

15.
利用脉冲激光沉积(PLD)方法制备了La2/3Ca1/3MnO3(LCMO)外延薄膜.然后利用微纳米加工技术对LCMO薄膜材料进行了局部改造,制造出宽度仅为83纳米的弱联接结构,并对此进行了一系列的物性改变研究.发现在测量电流不变(1μA)的情况下,R~T曲线在120K附近有一个尖锐的跳变,跳变的温度区间很窄.此外,测量电流和外加磁场的增加,都能对跳变现象产生抑制作用.目前认为这种现象的产生是由于相分离的原因导致的.  相似文献   

16.
利用额外推力模型研究了48Ca+238U俘获和熔合过程中的靶核形变效应.计算表明,在近垒和垒下能区,靶核形变使俘获截面和熔合截面增强,形成的复合核自旋分布展宽.  相似文献   

17.
Bee pollen contains proteins, amino acids, carbohydrates, fats, fatty acids, vitamins, polyphenols, and mineral nutrients that make it useful as a good nutritional supplement in the human diet. It has the richest elemental composition among bee products which is not uniform and consequently varies greatly depending on botanical and geographical origin. In polyfloral and selected monofloral bee pollen samples: sweet chestnut, maple, dandelion, rapeseed, flowering ash, buckwheat, common ivy, and plantain, the concentrations of P, S, Cl, K, Ca, Mn, Fe, Zn, Br, Rb, and Sr were determined. A non-destructive energy dispersive X-ray fluorescence spectrometry was used for elemental fingerprinting. The most abundant elements in Slovenian bee pollen are K, P, S, Ca, and Cl followed by Fe, Mn, Zn, Rb, Br, and Sr. Several statistically significant differences in the content of analysed elements were found between studied groups according to the botanical and geographical origin which can be related to soil and plant elemental composition and plant metabolism. The obtained data extend our previous chemical profiling of Slovenian bee pollen and contribute to a more precise evaluation of some essential mineral nutrients in bee pollen to cover recommended dietary allowances in human nutrition. Additionally, this work contributes to a better understanding of mineral nutrient requirements in honey bee nutrition and of the environmental and agricultural impact of this product.  相似文献   

18.
We present an experimental study of the aspect-ratio dependence of two-phase displacement flows in channels of rectangular cross section. Above a buoyancy-dependent threshold Ca[over ;]_{t}, we find that the bulk features of the flow depend only on a modified capillary number Ca[over ;]=[1+0.12(alpha-1)+0.018(alpha-1);{2}]Ca, where Ca is the unmodified capillary number and alpha is the aspect ratio. This novel scaling has tremendous practical significance because it implies that the bulk features of the flows in any rectangular channel can be inferred from those in a square channel for Ca[over ;]>Ca[over ;]_{t}.  相似文献   

19.
20.
Ion implantation of calcium has been proposed previously as a route to bioactive titanium surfaces and has been shown to stimulate promising cell and tissue responses. While the precise reasons for this behaviour remain poorly understood, it is clear that the nature of the Ca implanted surface changes rapidly on exposure to body fluids. In order to understand the processes taking place more clearly, the current work examined the simple interaction of Ca implanted Ti with water. The surface chemistry and compositional changes within the sub-surface region of the modified Ti were examined. On immersion in water, the concentration of implanted Ca ions was found to decrease both at the surface and throughout the implanted region. At the same time, the sub-surface oxygen concentration was found to increase dramatically. Although Ca implantation into Ti results in a thicker oxide layer at the surface, it appears that this layer no longer affords the underlying Ti the same protection from further oxidation provided by the native oxide. By examining samples implanted with O, Ti or Ar it was possible to conclude that this was specific to Ca implantation and not a result of the ion implantation process itself.  相似文献   

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