Bulk etch rates of CR-39 at high etchant concentrations:diffusionlimited etching

Systematic CR-39 bulk etching experiments were conducted over a wide range of concentrations(2–30 N)of NaOH-based etchant.Critical analysis and a deep discussion of the results are presented.A comprehensive nuclear track chemical etching data bank was developed.Three regimes of CR-39 bulk etching were identified.Regime I spans etchant concentrations from 2 to 12 N.Regime II spans concentrations from 12 to 25 N.We call this the dynamic bulk etching regime.Regime III is for concentrations greater than 25 N.In this regime,the bulk etch rate is saturated with respect to the etchant concentration.This classification is discussed and explained.The role of ethanol in NaOH-based etchants is explored and discussed.A parameter called the “reduced bulk etch rate” is defined here,which helps in analyzing the dependence of bulk etching on the amount of ethanol in the etchant.The bulk etch rate shows a natural logarithmic dependence on the density of ethanol in the etchant.

Bulk Etch Rate of LR 115 Polymeric Radon Detector

In this study, we used strippable LR 115 type 2 which is a Solid State Nuclear Track Detector (SSNTD) widely known for radon gas detection and measurement. The removed thickness of the active layer of samples of this SSNTD, were determined by measuring the average initial thickness (before etching) and residual thickness after 80 to 135 minutes chemical etching in the standard conditions, using an electronic comparator. These results allowed the calculation of the bulk etch rate of this detector in a simple way. The mean value obtained is (3.21 ± 0.21) μm/h. This value is in close agreement with those reported by different authors. It is an important parameter for alpha track counting on the sensitive surface of this polymeric detector after chemical etching because track density depends extremely on its removed layer. This SSNTD was then used for environmental radon gas monitoring in Côte d’Ivoire.

Measure the Bulk Etch Rate Using the Time-Diameter Method

The present work measured the bulk etch rate (VB?) of solid state nuclear track detector by taking the diameter time measurement of alpha particle in CR-39 detector. The values of the track diameter have been found by using TRACK-TEST program from Yu et al. function and Brun et al. function with different energies of alpha particles. The results showed that the time-diameter (t-d) method gave good results of the bulk etch rate (VB?) and these values were (1.705 and 1.72) μm·hr-1. They showed good agreement with the values measured by using the other methods, and it was a simple method because it required getting diameters of the tracks in the detector with the etching time.

High strain rate induced embrittlement of Zr-based bulk metallic glass

Quasi-static and high strain rate mechanical behavior of the Zr_ 1.25Ti_ 13.75Ni_ 10Cu_ 12.5Be_ 22.5 bulk metallic glass was determined covering strain rates from 1.02×10 -4s -1 to 3.258×103s -1. By use of split hopkinson pressure bar(SHPB) equipment, it is found that the alloy fractures in the high strain rate period with a strength well below that of its quasi-static counterpart and thus a strain rate induced embrittlement happens. Considering the glassy nature of the alloy and with careful analysis of the fracture morphology, dynamic damage accumulated in the high speed deformation period is suggested to be the reason for this embrittlement.

背腔刻蚀型横向激励薄膜体声波谐振器制备技术研究

随着移动通信技术的快速发展,薄膜体声波滤波器逐渐向高频和大带宽方向发展。该文研究了POI(LiNbO_(3)/SiO_(2)/Si)基片上背腔刻蚀型横向激励薄膜体声波谐振器制作工艺,通过研究POI基IDT光刻、背腔硅刻蚀等工艺,确定了IDT层曝光量和背腔刻蚀等关键工艺参数。研制出的背腔刻蚀型横向激励薄膜体声波谐振器,其谐振频率为4565 MHz,反谐振频率为5035 MHz,机电耦合系数为20.86%。此制备工艺对研究高频、大带宽薄膜体声波滤波器具有重要的参考意义。

Ti基块体非晶合金在酸性溶液中的腐蚀行为

研究Ti_(34.3)Zr_(31.5)Cu_(5)Ni_(5.5)Be_(23.7)块体非晶合金在不同浓度HCl和H_(2)SO_(4)溶液中的腐蚀行为。电化学测试与扫描电子显微镜分析发现,在极化过程中,Cl^(-)离子在HCl溶液中引发点蚀损伤,点蚀电位随溶液浓度的增大而降低,被腐蚀表面的损伤程度则与溶液浓度呈正相关。在H_(2)SO_(4)溶液中材料表面形成钝化膜,表现出良好的耐蚀性。X射线光电子能谱分析发现,随着HCl溶液浓度的增加,钝化膜的稳定性降低。通过浸泡实验得到4种材料的腐蚀速率。结果显示,Ti_(34.3)Zr_(31.5)Cu_(5)Ni_(5.5)Be_(23.7)块体非晶合金在HCl溶液中的耐腐蚀性能最好,其腐蚀速率为7.22×10^(-3) mm/a,约为316L不锈钢腐蚀速率的1/1294。

载畜率对冷蒿不同根际距离土壤细菌及其碳氮含量的影响

为了探究荒漠草原不同载畜率下半灌木植物冷蒿(Artemisia frigida)根、茎、叶碳氮含量与其根际、非根际土壤细菌群落结构的关系,利用高通量测序技术分析土壤(根际和非根际)细菌多样性和群落组成,测定根、茎、叶碳氮含量,分析细菌多样性与根茎叶碳氮含量的关系。结果表明:不同载畜率对冷蒿根茎叶的碳氮含量存在显著影响,中度和重度放牧会限制冷蒿的生长发育。不同载畜率下,根际土壤属水平下细菌的相对丰度均高于非根际土壤,根际与非根际土壤细菌Simpson指数、ACE指数均存在显著性差异(P<0.05)。冷蒿根茎叶碳氮含量与土壤中红色杆菌属和亚硝化球菌属的相对丰度存在相关性关系。

Effects of Heating Rate on the Process Parameters of Superplastic Forming for Zr_(55)Cu_(30)Al_(10)Ni_5

We investigated the effects of heating rate on the process parameters of superplastic forming for Zr55Cu30Al10Ni5 by differential scanning calorimetry. The continuous heating and isothermal annealing analyses suggested that the temperatures of glass transition and onset crystallization are heating rate-dependent in the supercooled liquid region. Then, the time-temperature-transformation diagram under different heating rates indicates that increasing the heating rate can lead to an increase of the incubation time at the same anneal temperature in the supercooled liquid region. Based on the Arrhenius relationship, we discovered that the incubation time increases by 1.08-1.11 times with double increase of the heating rate at the same anneal temperature, and then verified it by the data of literatures and the experimental results. The obtained curve of the max available incubation time reveals that the incubation time at a certain anneal temperature in the supercooled liquid region is not infinite, and will increase with increasing heating rate until this temperature shifts out of the supercooled liquid region because of exceeding critical heating rate. It is concluded that heating rate must be an important processing parameter of superplastic forming for Zr55Cu30Al10Ni5.

薄膜体声波滤波器的离子束刻蚀修频工艺

薄膜体声波滤波器因设计模型与器件性能存在匹配度问题及制造过程中各工序的累计误差导致频率一致性差,严重影响了产品良率,因此实现晶圆级别的频率修整十分必要。介绍了离子束刻蚀工艺的原理、技术特点与优势,研究了刻蚀电压、刻蚀电流、刻蚀距离、Ar气体体积流量及单次刻蚀量对刻蚀效果的影响,表征了离子束刻蚀工艺对AlN钝化层厚度均一性、刻蚀精度及粗糙度的影响。探究了离子束刻蚀工艺在薄膜体声波滤波器频率修整上的应用,表征了离子束刻蚀工艺对钝化层的表面形貌及晶圆应力的影响。研究结果表明,刻蚀电压为1500 V、刻蚀电流为18 mA、刻蚀气体体积流量为4 cm^(3)/min、刻蚀距离为80 mm时,刻蚀精度高,具有一定借鉴意义;通过3轮电性能测试分析和离子束刻蚀工艺,频率标准差仅为1.23 MHz,大幅提升了薄膜体声波滤波器的频率一致性。

Variable Chlorine Decay Rate Modeling of the Matsapha Town Water Network Using EPANET Program

A variable chlorine decay rate modeling of the Matsapha town water network was developed based on initial chlorine dosages. The model was adequately described by a second order rate function of the chlorine decay rate with respect to the initial chlorine dose applied. Simulations of chlorine residuals within the Matsapha water distribution network were run using the EPANET 2.0 program at different initial chlorine dosages and using the variable decay rate as described by the second order model. The measurement results indicated that the use of constant decay rate tended to underestimate chlorine residuals leading to potentially excess dosages with the associated chemical cost and side effects. The error between the two rate models varied between 0% and 15%. It is suggested that the use of water quality simulation programs such as EPANET be enhanced through the extension programs that accommodate variable rate modeling of chlorine residuals within distribution systems.

Decline of nucleation in the heating process with a high heating rate

The effect of the heating rate on the nucleation of metallic glass in a rapid heating process starting from the glass transition temperature is investigated. The critical nucleus radius increases with the increase of the temperature of the undercooling liquid. If the increment rate of the critical nucleus radius, owing to the heating process, is higher than the growth rate of the nuclei, the nuclei generated at the low temperature will become the embryos at the high temperature. This means that the high heating rate can make no nucleation happen in the heating process. In consideration of the interfacial energy, the growth rate of the nuclei increases with the increase of their size and the growth rate of the critical nucleus is zero. Thus, the lower heating rate can also make the nuclei decline partially. Finally, this theory is used to analyze the nucleation process during laser remelting metallic glass.

基于爆破矿石图像分割优化算法的大块率统计方法

矿石图像分割效果受光照条件、目标密集性及边缘对比度低等因素制约,致使大块率统计精度偏低.为此以鞍千矿爆破矿石图像为数据源,首先利用双边滤波算法去除特征增强后的图像噪声,然后分别采用自适应阈值算法和整体嵌套边缘检测(holistically-nested edge detection, HED)算法初步分割矿石图像,再利用形态学和去除连通域算法去除因矿石表面纹理形成的分割孔洞,进一步融合两种分割结果,引入基于距离运算的分水岭算法消除矿石图像欠分割现象,最终实现矿石图像的优化分割.研究结果表明,该方法可有效提高爆破矿石图像分割准确性,实现露天矿爆破大块率精确统计,为爆破效果智能评价提供技术支持.

Mechanical behavior of Cu-Zr bulk metallic glasses (BMGs): A molecular dynamics approach

In the present work, three-dimensional molecular dynamics simulation is carried out to elucidate the nanoinden- tation behaviors of CuZr Bulk metallic glasses （BMGs）. The substrate indenter system is modeled using hybrid interatomic potentials including both many-body Finnis Sinclair （FS） and two-body Morse potentials. A spherical rigid indenter （diameter= 60 A（1 A = 10 ^-10 m）） is employed to simulate the indentation process. Three samples of BMGs including Cu25Zr75, CusoZr50, and Cu75Zr25 are designed and the metallic glasses are formed by rapid cooling from the melt state at about 2000 K. The radial distribution functions are analyzed to reveal the dynamical evolution of the structure of the atoms with different compositions and different cooling rates. The mechanical behavior can be well understood in terms of load-depth curves and Hardness-depth curves during the nanoindentation process. Our results indicate a positive linear relationship between the hardness and the Cu concentration of the BMG sample. To reveal the importance of cooling rate provided during the processing of BMGs, we investigate the indentation behaviors of CusoZr50 at three different quenching rates. Nanoindentation results and radial distribution function （RDF） curves at room temperature indicate that a sample can be made harder and more stable by slowing down the quenching rate.

Testing of High-Strength Zr-Based Bulk Metallic Glass with the Split Hopkinson Pressure Bar

The split Hopkinson pressure bar （SHPB） was used to determine the dynamic compressive strength of the high-strength Zr38Ti17Cu10.5Co12Be22.5 bulk metallic glass at strain rate on the order of 102 s^-1. It is shown that at high strain rates beyond about 1 000 s^-1, uniform deformation within the metallic glass specimen could not be achieved and dispersion in the transmitted pulse can lead to discrepancies in measuring the dynamic failure strength of the present Zr-based bulk metallic glass. Based on these reasons, a copper insert was placed between the strike bar and the input bar to obtain reliable and consistent experimental data for testing of the Zr38Ti17Cu10.5Co12Be22.5 bulk metallic glass using the SHPB. Negative strain rate sensitivity was found in the present Zr-based bulk metallic glass.

工艺条件对厨余垃圾生物干化效果的影响

为了研究各工艺条件(调理剂类型、调理剂添加比例、通风速率)对厨余垃圾生物干化效果的影响,为厨余垃圾生物干化工程应用提供指导。分别选取3种调理剂、4个调理剂添加比例、4个通风速率,分析生物干化过程中物料的温度、含水率、挥发性固体(volatile solid,VS)降解率变化,评价其生物干化效果。结果表明:添加木屑作为调理剂可以缩短升温期、延长高温期。加入木屑的处理组物料含水率降幅为31.97%,比只有厨余垃圾的对照组高18.57%。添加15%木屑的处理组生物干化效果最佳,温度最高可达63.8℃,含水率降低了32.36%。不同的通风速率影响物料的温度和水分的散失,通风速率为0.4 L/(kg·min)时有机物消耗最少,水分去除效果最佳。实际厨余垃圾生物干化工业应用可以考虑添加15%木屑做为调理剂,通风速率设为0.4 L/(kg·min)。

基于U-Net和改进分水岭算法的露天矿爆堆矿石图像分割方法

爆破大块率是反映爆破效果的关键指标,其统计精度主要依赖于爆堆矿石图像分割的准确性。由于爆堆矿石图像中存在矿石目标分布密集、边缘对比度低等问题,致使传统图像分割方法难以准确分割爆堆矿石图像。因此,提出了一种基于U-Net和改进分水岭算法的露天矿爆堆矿石图像分割方法,以实现大块率的精准统计。首先利用无人机在哑巴岭露天矿爆破现场拍摄爆堆矿石图像,制作爆堆矿石图像数据集;然后利用深度学习算法建立了UNet网络架构,同时融合了高级语义信息和低级语义信息,建立了爆堆矿石图像分割模型,再利用训练后的模型对爆堆矿石图像进行初步分割,进一步采用基于距离运算的分水岭算法优化了分割结果;最后评估了该方法的分割精度。试验结果表明:该算法可准确分割露天矿爆堆矿石图像,为露天矿爆破大块率统计、爆破效果智能评价提供技术支持。

某高氧化率硫化铅锌矿混合浮选试验研究

针对某硫化铅锌矿氧化率高、现场浮选指标低的问题,采用石灰+CD⁃2(800 g/t+300 g/t)为黄铁矿抑制剂、CD⁃1+水玻璃(600 g/t+600 g/t)为脉石抑制剂、硫化钠(500 g/t)为硫化剂、硫酸铜(500 g/t)为活化剂、丁基黄药(200 g/t)为捕收剂、松醇油(21 g/t)为起泡剂,经两段粗选、两段扫选、一段精粗选、两段精选、两段精扫选的优化闭路浮选,混合精矿中铅品位和回收率分别为16.25%和65.05%,锌品位和回收率分别为27.69%和92.49%。与原工艺流程生产指标相比,铅品位和回收率分别提高了2.24个百分点和9.36个百分点,锌品位和回收率分别提高了1.57个百分点和5.14个百分点。

烧结温度对掺加二次铝灰及钻井岩屑制备陶粒支撑剂性能的影响

目的钻井岩屑作为油气开发过程中所产生的固体废物,产生量巨大且资源化利用途径单一。使用钻井岩屑及二次铝灰协同制备水力压裂用陶粒支撑剂,不仅可有效拓宽钻井岩屑资源化利用途径,而且还可降低油气开发生产成本。方法采用二级铝矾土为主要原料,添加质量分数分别为20%的钻井岩屑和10%的二次铝灰,甲基纤维素作为黏结剂,于不同烧结温度下制备了低密度高强度压裂用陶粒支撑剂,研究烧结温度对支撑剂结构、晶相组成及其产品性能的影响。结果钻井岩屑须经预处理,以降低岩屑中有机物对后续生胚烧结的影响。当烧结温度为1300℃时,其主晶相为刚玉,次晶相为钡长石,支撑剂的体积密度为1.45 g/cm^(3),52 MPa闭合压力下破碎率为5.26%,满足SY/T 5108-2014《水力压裂和砾石充填作业用支撑剂性能测试方法》对0.38 mm/0.25 mm支撑剂的质量要求。结论烧结温度是制备陶粒支撑剂的关键控制参数。随着烧结温度的增加,支撑剂内部产生的液相将逐渐增多,有利于加快扩散和增大传质速率,促进支撑剂的致密化,但过多的液相则会导致支撑剂膨胀变形,对抗破碎能力产生不利影响。以钻井岩屑、铝灰、铝矾土为原料,适宜的烧结温度建议为1260~1300℃。

锂电池隔膜用聚乙烯的结构与性能

采用高温凝胶渗透色谱仪、熔体流动速率仪、堆积密度计和扫描电子显微镜等对国内外几种锂电池隔膜用聚乙烯(PE)的相对分子质量、熔体流动速率、堆密度和形貌等进行了分析和表征,并采用PE/白油溶胀的方法研究了其溶胀性能。结果表明:试样B4的粒径集中在75~150μm,堆密度最高为0.50 g/cm^(3),熔体流动速率为0.01 g/10 min,相对分子质量分布为4.17,形态规整,溶胀效果最好,更紧实,最适用于制备锂电池隔膜。由此表明:适用于生产锂电池隔膜的PE具有颗粒分布均匀、形态规整、相对分子质量分布窄、溶胀性能好等特点。

喷灌压力、喷嘴直径和喷洒历时对土壤入渗性能的影响

选取适宜的允许喷灌强度是避免喷灌条件下水土流失的重要措施之一。通过田间试验,测定了不同喷灌压力与喷嘴直径条件下土壤结皮厚度、表层土壤容重以及土壤入渗性能随喷洒历时的动态变化。试验处理包括2种质地土壤(壤质砂土和粉质黏壤土)、3个喷灌压力(103,138,172 kPa)和3个喷嘴直径(3.97,5.95,7.94 mm)。结果表明,喷灌压力越大,土壤结皮厚度和表层容重越小,土壤稳定入渗率越大。喷嘴直径越大,土壤结皮厚度和表层容重越大,土壤稳定入渗率越小。土壤结皮厚度和表层容重随着喷洒历时的增加显著增大,而土壤稳定入渗率则随之对数减小。喷洒动能强度是一个描述喷洒水滴对土壤入渗率影响的优选参数。研究结果为允许喷灌强度的确定提供科学依据。