铬黑T-溴酸钠催化动力学分光光度法测定铼

基于在硫酸介质中,铼催化溴酸钠氧化铬黑T的褪色反应,建立了测定铼的光度分析新方法。确定了催化体系的动力学条件,计算得出催化反应的表观活化能Ea=39.12KJ/mol,反应速率常数为K=1.248×10-3/s。在选定的试验优条件下,铼的浓度在0~10.02mg/L范围内与相对吸光度呈良好的线性关系,检出限为2.7675mg/L。方法所用仪器简单,操作简便。     

流动注射-分光光度法测定孔隙水中的氨氮

建立了流动注射分光光度法测定孔隙水中氨氮的方法。在优化好的试验条件下,方法检出限为0.90μg/L,浓度在5.00~500μg/L具有良好的线性关系(相关系数R~2=0.9996)。相对标准偏差为0.70%~1.42%(n=8),加标回收率为97.6%~103.2%。与国标法测定结果的相对误差为0.2%~4.5%。分析速率达45个/h。     

商南茶叶中微量硒的提取与测定

采用正交设计[L16（45）]试验,研究了茶叶中微量硒的提取和测定条件。在此基础上建立了铁氰化钾-盐酸存在下用微波消解-流动注射-氢化物发生-原子荧光光度法测定茶叶中微量硒的新方法。该方法的回归方程为y=62.91x-0.3529,R=0.9996,线性范围为0～20μg/L,检出限为0.01μg/L,相对标准偏差为2.7%（n=11）。用此方法测定了5种商南茶叶中的微量硒,回收率96.5%～103.4%,相对标准偏差2.9%～4.1%（n=7）,结果令人满意。     

在线固相萃取-高效液相色谱法同时测定水中甲萘威和阿特拉津

利用双三元液相色谱仪,建立了在线固相萃取(On-line SPE)-高效液相色谱水体中的甲萘威和阿特拉津的新方法。通过在线固相萃取-高效液相色谱法同时分析水中的甲萘威和阿特拉津,两种物质在0.5~20μg/L范围内,相关系数R2>0.9993;进样量为2.500mL时,甲萘威检出限为0.004g/L,相对误差为-5.1%^-1.5%,相对标准偏差为0.29%~0.97%,阿特拉津检出限为0.008μg/L,相对误差为-3.5%~5.0%,相对标准偏差为1.5%~2.8%。实际水样的加标回收率,甲萘威为91.8%~104%,阿特拉津为91.6%~101%。实验证明该方法快速、准确有效地用于水体中的甲萘威和阿特拉津的测定。     

超高效液相色谱-三重四极杆质谱联用法测定血浆和尿液中米酵菌酸和异米酵菌酸

建立了超高效液相色谱-三重四极杆串联质谱法(UPLC-MS/MS)测定生物样品中米酵菌酸和异米酵菌酸的方法。将米酵菌酸在2 mol/L KOH溶液中100℃加热反应2 h制备异米酵菌酸标准品,并通过与对照品的质谱、色谱、紫外光谱比较而确认。血浆样品用含0.5%氨水的乙腈溶液-甲醇(9∶1,V/V)沉淀除去血浆蛋白,在酸性条件下用正己烷萃取净化;尿液样品使用正己烷在酸性条件下萃取净化。选择Acquity BEH C18色谱柱,以0.05%甲酸-乙腈溶液(V/V)-0.05%甲酸水溶液(V/V)为流动相进行洗脱,电喷雾负离子多离子监测模式(MRM)检测,基质加标标准曲线外标法定量。结果表明:血浆和尿液中米酵菌酸和异米酵菌酸的线性范围均为0.05~10.0μg/L,相关系数大于0.998,平均加标回收率在92%~106%之间,相对标准偏差均为2.4%~13%(n=6),方法的检出限(S/N=3)均为0.02μg/L。该方法简单、灵敏、准确,可用于鉴定椰毒假单胞菌引起的中毒。     

萃取光度法测定钼精矿浸出液中的铼含量

使用萃取光度法对钼精矿浸出液中的铼进行测定,对萃取、显色及测定过程进行了试验,优化了掩蔽剂用量、萃取次数、萃取时间、pH、水浴温度及还原剂用量等条件。结果表明:在波长426nm处,铼在2~30μg/mL浓度范围内与其吸光度呈良好的线性关系,RSD小于2.3%,检出限(3s/k)为0.08μg/mL,回收率在91.2%~103.4.8%之间,与ICP-AES标准加入法进行对比,结果一致。     

离子选择电极法测定土壤全氟化物熔融条件的控制

离子选择电极法测定土壤全氟化物前处理过程中的熔融条件控制至关重要。使用马弗炉或高温烘箱直接升温,熔融反应过于剧烈,测定结果误差大。本实验就氢氧化钠与土壤的比例、马弗炉的升温方式、熔融最终温度和时间的选择进行相关研究。通过实际样品和有证标准样品多次试验验证:本方法检出限为12.5mg/kg;平行测定的相对标准偏差RSD=2.0%~5.9%;有证标准样品测定结果与真值的相对误差RE%=-1.1%~1.3%。程序升温控制熔融条件下,样品测定的准确、可靠性得到了改善。     

ICP-AES标准加入法测定铝酸钠溶液中硫酸钠含量

采用ICP-AES标准加入法测定铝酸钠溶液中硫酸钠含量,试样中直接加过量盐酸酸化然后加热使溶液中S2-、S2O32-和SO32-等低价硫分解,过滤硫代硫酸钠与盐酸反应生成的硫单质后测定滤液,采用标准加入法抵消复杂基体的干扰,方法简单快速,线性范围宽,检出限(3S/N)为0.028g/L,不同浓度样品加标回收率在99.2%~100.7%之间,相对标准偏差(n=10)分别在1.22%~2.42%之间,本法测定值和重量法测定值相符,完全可以满足生产控制分析需求。     

气相色谱-质谱法分析固井水泥浆添加剂中磷酸三丁酯

采用气相色谱-质谱法测定固井水泥浆添加剂中磷酸三丁酯(TBP)的含量。选择m/z=99、155和211的麦氏重排离子为特征离子。TBP在0.20g/L~5.13g/L含量范围内,其特征离子丰度与含量呈线性关系,线性方程为:Y=1.05×107 X+1.75×105,相关系数γ2=0.999,方法检出限(S/N=3)0.000073g/L,定量限(S/N=10)0.00024g/L,平均回收率为106.2%~109.2,相对标准偏差为0.36%~1.70%(n=6)。实际应用表明:该方法适用于油田固井水泥浆添加剂中磷酸三丁酯的质控分析。     

SPE-UPLC-MS/MS法测定牛奶中β-内酰胺类药物残留

本试验应用固相萃取技术(SPE),结合超高效液相色谱-串联质谱联用仪(UPLC-MS/MS),建立了快速测定生鲜乳中!-内酰胺类药物残留的方法。样品经乙腈提取,Oaiss PRiME HLB固相萃取小柱净化后,以0.1%甲酸乙腈溶液和0.1%水溶液为流动相,Waters C_(18)色谱柱进行分离;多反应监测(MRM)模式,外标法进行定量。方法回收率在70.1%~95.5%之间;相对标准偏差(n=3)范围为1.0%~9.1%;线性范围为0.002~0.100mg/L;检出限为0.1~0.6μg/kg;定量限为0.3~1.8μg/kg。表明该方法专属性强、灵敏度高,适用于生鲜乳中β-内酰胺类药物残留的测定。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.