高纯水中痕量阴离子的测定

本文介绍了一种测定高纯水中痕量阴离子的样品预浓缩方法可供电厂及半导体工业监测之用。该法使用了一种可在任何离子色谱系统上连接的样品预浓缩易于自动化的预浓缩装置,即ＳＣＡＮ＾ＴＭ１０００样品处理器。由于ＳＣＡＮ＾ＴＭ１０００样品处理器用检测器的洗脱剂把样品带入浓缩柱中,不需要外部的水泵。这样就简化了痕量分析所用仪器。在使用自动进样器时,ＳＣＡＮ＾ＴＭ１０００可以进行无人管理的自动化分析。     

在线基体消除-毛细管离子色谱测定有机溶剂中的痕量阴离子

建立了在线基体消除-毛细管离子色谱测定有机溶剂中痕量阴离子的方法。有机溶剂样品经过阴离子浓缩柱（MAC200整体柱）,痕量目标阴离子被浓缩的同时,有机溶剂不被保留而去除,接着目标离子转入毛细管离子色谱系统进行分析。六种阴离子（氟离子、氯离子、亚硝酸根、硝酸根、硫酸根和磷酸根）在1-100μg/L线性范围内,相关系数（r2）为0.9991～0.9999,考察的阴离子检出限（以S/N=3计）为2.2-34.8ng/L。用于实际样品检测,取得了很好的效果。     

气相色谱-质谱法检测土壤中痕量芥子气

建立气相色谱-质谱选择离子检测土壤中痕量芥子气的方法。该方法采用二氯甲烷萃取土壤中的芥子气,萃取液经净化、浓缩,加入内标丁基硫醚后进行分析,可实现对土壤中0.02mg/kg芥子气的定量检出,且加标回收率大于70%,相对标准偏差小于10%。     

梯度离子色谱法在火电厂水汽监督中的应用

研究了用梯度淋洗离子色谱法／电导检测器分析有机酸与无机阴离子的色谱条件，建立了最佳梯度程序。通过浓缩柱的富集，最低检测限可达10^-12，对大多数离子的相对标准偏差在5％以下。此方法可用于火电厂水汽系统中痕量低分子有机酸和无机阴离子的快速、准确分析。     

浓过氧化氢试剂中痕量阴离子的离子色谱法测定

建立了浓过氧化氢试剂中痕量阴离子的分析方法。样品中的过氧化氢基体用铂丝在小烧杯中加热分解 ,处理后的样品溶液注入离子色谱系统进行测定。常见阴离子的检出限为 10 -9级。Cl-和SO2 -4的标准加入回收率分别为 10 9.7%和 10 2 %。方法已成功地用于商品过氧化氢的分析。     

大体积直接进样-离子色谱法测定高纯水中痕量阴离子

建立了一种采用大体积直接进样－离子色谱测定高纯水中痕量阴离子的新方法。采用高容量的IonPac AS9HC阴离子交换色谱柱，以11.5mmol/L Na2CO3为淋洗液，流速1.0mL/min,可在20min内同时测定7种常见阴离子，采用新型的阴离子Atlas电解抑制器，可显著降低基线噪音，结合500μL定量环，对F^-,Cl^-,NO2^-,Br^-，NO3^2-，PO4^3-,SO4^2-的检测限分别为0.09μg/L，0.20μg/L,0.46μg/L,0.89μg/L,0.76μg/L,0.96μg/L,0.92μg/L。应用此方法对高纯水中的痕量阴离子进行了测定。     

离子色谱法测定瓶装矿泉水中痕量溴酸盐

建立测定饮用水中痕量溴酸盐的离子色谱法,并对北京地区超市瓶装矿泉水进行随机抽样调查。方法采用Di-onex ICS-1000型离子色谱,IonPac AS23阴离子交换柱,Na2CO3/NaHCO3等度淋洗,电导检测器,直接进样,进样体积为500μL。结果离子色谱法测定饮用水中痕量溴酸盐的检出限为0.2μg/L;在1～100μg/L范围内具有良好的线性关系（r=0.9999）;5种不同浓度标准溶液的相对标准偏差（RSD）均小于10%;对北京地区超市16种瓶装矿泉水样品中痕量溴酸盐进行了检测,加标回收率在98%～106%之间,样品检出浓度在1.78～14.49μg/L之间,其中有2种矿泉水样品溴酸盐含量超过了限值（10μg/L）。结论离子色谱法测定饮用水中痕量溴酸盐具有灵敏度高、操作简单、分离效果好、重现性卓越等特点。市售瓶装矿泉水具有一定的致癌危险性,建议相关部门依据新国标要求加强对市售瓶装矿泉水的监测和管理。     

第二届中日韩三国离子色谱会议暨第十一届全国离子色谱学术报告会征文通知

(第一轮)由中日韩三国共同发起的第二届中日韩三国离子色谱会议暨第十一届全国离子色谱学术报告会,定于2006年11月26日-12月1日在浙江省杭州市召开。会议预计将有超过一百名的国内代表,以及日本、韩国的40多名学者和专家参加。大会将邀请国内外著名离子色谱专家作十余个专题报告。现将征文内容及有关事项通知如下:1.征文内容(1)全部离子色谱及相关技术如:抑制器、淋洗液发生、生物分离、样品处理、故障处理、超痕量分析、预浓缩、色谱柱技术、方法建立等。(2)离子色谱分离和检测技术。(3)离子色谱与质谱、等离子体发射光谱的联用技术。(4)离…     

利用国产离子色谱抑制器建立单泵柱切换系统

建立以国产离子色谱抑制器为基础的简化的离子排斥-离子交换柱切换系统,成功测定了高浓度弱酸基体中的痕量无机阴离子。与传统的柱切换系统相比,本系统只用一个泵;同时充分发挥了国产抑制器应用在单泵柱切换系统具有体积小、耐压性强、抑制作用好等优点。利用本系统,优化色谱条件,成功测定了酒石酸和柠檬酸中的氯离子、硫酸根离子和硝酸根离子,降低了方法的检出限(0.4～1.6μg/L,S/N=3),并获得了理想的回收率(78.2%～112.9%)。     

核电水质中超痕量Cl-和SO2-4分析方法探讨

研究了在新型离子色谱中采用淋洗液在线发生技术和对OH^-选择性高的分离柱的条件下，建立适当的梯度淋洗程序和样品浓缩富集方法，以满足对核电水质中超痕量Cl^-和SO4^2-进行准确测定的要求，实验结果表明该方法能够非常准确地对水质中0.02ng/mL以上的Cl^-和SO4^2-，在0－5ng/mL以内的线性相关系数分别是0.9997和0.9998，并且有着非常好的重现性。     

脉冲增压毛细管分离富集ID-ICP-MS测定地质样品中微量锂的方法研究

采用一种脉冲增压毛细管柱 ,用于锂的分离富集。其原理类似于高效液相色谱 ,但使用钢瓶气为动力脉冲驱动液相在固定相中流动。使用粒度很细的固定相材料 ,惰性气体和液相脉冲交替通过固定相 ,使固定相的死体积减小到最低程度 ,从而获得很高的分离富集系数。试验了一种无机固定相材料和树脂材料用于锂的分离富集。结果表明 :无机材料能高效富集锂 ,但选择性较差、本底杂质较多 ;阳离子交换树脂分离效果好、本底低 ,能从镁、钙等大多数离子中很好地将锂分离 ,几乎没有拖尾现象 ,回收率达到 97% ,分离纯度高。分离后 ,用 ICP-MS测定锂同位素的比值 ,具有较高的测量精密度。用同位素稀释电感耦合等离子体质谱( ID-ICP-MS)测定地质样品中微量锂 ,结果相对标准偏差 sr<3%。方法检出限低 ,精密度高 ,分析速度快 ,是测定锂的较理想方法。     

Wear durability studies of ultra-thin perfluoropolyether lubricant on magnetic hard disks

This paper presents wear and friction studies on ultra-thin (~2 nm) film of perfluoropolyether (PFPE) coated on glass substrate magnetic hard disks. The lubricant was coated on the disk by the dip-coating method and the tribological tests were carried out by sliding a 3 mm diameter glass ball slider (normal load=20 mN) on the rotating disk surface. Lube thickness and lube wear profile were measured using an ellipsometer whereas the worn disk surface was studied using a surface reflectivity analyzer. The sliding speed and the lube bonding conditions were varied during the test. From the results, it is concluded that about 80% bonding of the lube to the disk surface leads to an increase in the wear durability of the lubricant by a factor of 2 when compared to the as-lubed condition. Lube bonding has an effect on increasing the coefficient of friction. Initially, increasing sliding speed increases both friction and wear but for very high sliding speed these values tend to decrease. The glass ball surface showed wear due to asperity interactions as well as lube transfer from the disk to the glass surface.     

蛋膜固相萃取-石墨炉原子吸收光谱法测定酵母粉中的痕量镉

本文研究了蛋膜固相萃取-石墨炉原子吸收光谱法测定酵母粉中痕量镉的方法,实验中对蛋膜吸附镉的性能、洗脱剂的选择、洗脱液用量和干扰离子的影响等进行了探讨。结果表明在0.1～2.0mol/L氨水介质中,蛋膜能完全吸附镉。吸附的金属离子可以用0.48mol/L盐酸2mL完全洗脱下来。方法的检出限为0.0037ng/mL,回收率为97.8%～102%。该方法操作简单,准确性好,灵敏度高,适用于酵母粉和食品中痕量镉的分析,能获得满意的结果。     

浊点萃取在金属离子分析中的应用

通过表面活性剂浊点特性实现胶束相分离以达到样品预富集,是一种新兴的液 -液萃取方法。该方法广泛应用于痕量有机物、金属离子(通过形成螯合物)以及生物大 分子的提取,具有低毒、高效、安全、简便等特点,其富集率最高可达100％。     

Air Bearing Design to Prevent Reverse Flow from the Trailing Edge of the Slider

A simulation approach that relies on an analysis of the flow patterns closest to an air bearing surface (ABS) was used to predict the lubricant accumulation on the ABS of a head slider. The lubricant accumulation patterns obtained through the simulation were in good agreement with experimental results and with our experimental apparatus. We used this method to study and analyze flow pattern droplets close to the trailing edge of a number of sliders and found that there was a reverse flow from the slider’s trailing edge on both sides of the trailing pad and behind the read/write element, which could result in a lubricant accumulation on the slider surface close to the trailing edge of a slider and thus lead a transient slider vibration and magnetic-signal loss in a hard disk drive. Further simulations and analyses revealed that the reverse flow is dependent on the depth of slider surface on adjacent to the trailing edge of the slider, and that if the depth is less than a critical depth, which is dependent on the velocity of the disk, the reverse flow could be eliminated. On the basis of these findings, we propose a new ABS design concept for effectively suppressing the reverse flow of lubricants from the trailing edge of the slider. In this concept, the slider has a “smooth flow pad” and the depths of outlet recesses are specified as being smaller than the critical depth. It was confirmed by both simulation and experiment that lube accumulation on the slider surface is obviously decreased and the reliability of a hard disk drive with this air bearing design is consequently improved.     

The effects of texture height and thickness of amorphous carbon nitride coating of a hard disk slider on the friction and wear of the slider against a disk

In order to minimize the stiction force caused by contact of the extremely smooth surfaces of head sliders and disks in hard disk drives, texture is usually applied on the disk surface. For future contact/near-contact recording, the stiction-induced high friction between slider and disk will become a problem. Texture on the slider/disk interface will still be an expected method to reduce friction. Recently, it was suggested to texture the slider surface. A protective coating is usually required on the textured slider surface to reduce wear of the texture. The results showed that texture on the slider surface was effective in reducing the friction between head sliders and disks. On the other hand, the texture and coating on the slider surface increase the spacing between the read/write element and the magnetic layer of the disk. The necessary and effective texture height and coating thickness are still not clear. In the present research, island-type textures with different heights (3–18 mn) were formed on slider surfaces by ion-beam etching. Amorphous carbon nitride (a-CN_x) coatings of different thicknesses (0–50 nm) were coated on the textured slider surfaces as a protective overcoat. The friction and wear properties of these sliders were evaluated by constant-speed drag tests against hard disks coated with diamond-like carbon (DLC). The results show that 2 nm texture on a slider surface is sufficient for low (0.3–0.5) and stable friction of the slider against the disk in a drag test, and coatings thicker than 5 nm show similar wear resistances of the texture on slider surfaces.     

基于有限元法和Taguchi方法的移动硬盘耐撞性能稳健设计

运用Taguchi参数设计方法,提出了基于数值模拟的移动硬盘跌落冲击耐撞性能稳健设计方法。以6.3cm(2.5in)移动硬盘为研究对象,建立了基于有限元软件ANSYS/LS-DYNA的移动硬盘跌落冲击三维有限元模型。分析了关键结构参数对移动硬盘耐撞性能稳健性的影响,进行了移动硬盘耐撞性能稳健设计,获得使磁盘盘片接触面等效应力对地面硬度变化具有稳健性的最优参数水平组合,并进行了仿真试验验证分析。该方法为改进设计提高移动硬盘耐撞性能提供了理论依据。     

Optimal disk clamp design to minimize stress variation of disks in a hard disk drive

To avoid disk waviness and warpage in a hard disk drive, it is desirable for the stress distribution on disks fastened to a spindle motor by a clamp to be uniform in the circumferential direction while sufficient clamping force is maintained. The objective of this work is to find a clamp configuration that minimizes the circumferential stress variation on the disks while maximizing the clamping force. Topology and shape optimization methods were employed to find the optimal clamp configuration. To facilitate the optimization problem, a model for the surface contact between the clamp and the top disk was simplified to a static model where the disk clamp and spring were connected. By incorporating the surface recess, the optimized clamp has equal stiffness in the circumferential direction, except for the four tooling hole areas. Numerical simulation confirmed that the optimized clamp reduced the stress variation by about 78% without sacrificing the clamping force; in fact, it increased the clamping force.