氟环唑在苹果及土壤中的残留动态研究

为了解氟环唑在苹果上使用的安全性,分别在天津和安徽两地进行了氟环唑在苹果和土壤中的残留消解规律和最终残留研究,试样经溶剂浸泡提取,层析柱净化,用气相色谱定量。结果表明,氟环唑的最低检出量为1.93×10-13g,在苹果和土壤中的最低检出浓度分别为9.65×10-5mg·kg-1和1.21×10-4mg·kg-1;苹果中氟环唑的平均回收率为88.94%～91.86%,变异系数为5.88%～6.63%;土壤中氟环唑的平均回收率为98.89%～103.03%,变异系数为2.96%～6.33%。氟环唑消解较快,在苹果中其半衰期两地分别为8.21d和11.46d,土壤中其半衰期两地分别为11.53d和16.43d。按推荐剂量(900倍稀释液)2倍施用3次,距最后一次施药间隔21d后,苹果中氟环唑的残留量为0.267～0.033mg·kg-1,土壤中的氟环唑残留量为0.143mg·kg-1～0.123mg·kg-1。说明该药属易分解农药(T1/2<30d),按推荐剂量使用是安全的。     

杀螟丹98% 可溶性粉剂在甘蓝和土壤中的残留动态研究

通过大田试验及气相色谱分析，研究了杀螟丹在甘蓝和土壤中的残留动态。结果表明：杀螟丹在甘蓝和土壤中的残留半衰期分别为2.8天和2.2天。按建议剂量0.075g/m^2和2倍剂量0.15g/m^2施用杀螟丹98％可溶性粉剂，使用3次，采样距最后一次施药间隔期7天时，甘蓝和土壤中的残留量分别为0.0521,0.0057mg/kg和0.1058,0.0012mg/kg。     

铜陵矿集区土壤Cu缓变型地球化学灾害研究

文章根据缓变型地球化学灾害(DGH)模型,研究了铜陵金属矿集区凤凰山地区土壤中Cu的缓变型地球化学特征。结果表明:在pH为5.0、5.0～2.0时,其缓变型地球化学灾害临界点分别为222.22 mg·kg-1、81.68 mg·kg-1,爆发点分别为438.75 mg·kg-1、384.99 mg·kg-1。随着酸性程度的增强,具有爆发Cu缓变型地球化学灾害可能的区域面积增大,临界点和爆发点均提前。地球化学背景异常和矿业开发的人为活动导致土壤重金属长期输入;酸雨和矿业的酸性排水引起土壤理化性质的改变;环境容量变小等因素是DGH的主要原因。     

三种浸种剂对水稻浸种的安全性试验及对水稻恶苗病预防效果评价

为验证水稻浸种剂17%杀螟·乙蒜素可湿性粉剂;20%氰烯·杀螟丹;12%氟啶·戊·杀螟三种药剂对稻种催芽的安全性及对水稻恶苗病防治效果,使用17%杀螟·乙蒜湿性粉剂250倍液;20%氰烯·杀螟丹可湿性粉剂和12%氟啶·戊·杀螟可分散粉剂配制不同浓度梯度的药液浸种进行催芽培养,统计发芽率和成苗率并对各处理药剂浸种后田间恶苗病实际防效调查。结果表明:17%杀螟·乙蒜素可湿性粉剂250倍液发芽率、成苗率以及田间恶苗病的实际防效均为最优。20%氰烯·杀螟丹和12%氟啶·戊·杀螟最高倍液和最低倍液对水稻的成苗率均有不同程度的影响。生产上推荐使用17%杀螟·乙蒜素可湿性粉剂250倍液;20%氰烯·杀螟丹1 000倍液;12%氟啶·戊·杀螟1 200倍液对水稻浸种。     

寒冷地区日光温室茄子高产栽培技术

一、嫁接前应注意的问题 1.床土消毒 选用前茬非茄科种植土壤,最好是种植大田作物土壤,大田土与优质有机肥按比例6:4配好床土,用50%多菌灵可湿性粉剂15～20 g和50%辛硫磷乳油150mL,兑水15～20 kg喷洒苗床,拌匀后建堆,外盖一层旧棚膜,消毒处理15 d后,建苗床并装营养钵.     

超高效液相色谱-三重四极杆串联质谱法分析茶叶中联苯肼酯残留与风险评估

建立了QuEChERS分散固相萃取技术净化茶叶,超高效液相色谱-三重四极杆串联质谱（UPLC-MS/MS）法测定茶叶鲜叶和成茶中联苯肼酯残留的分析方法。利用该方法研究了43%联苯肼酯悬浮剂在茶叶鲜叶生长中的残留降解规律,并对其在茶叶饮用中的安全性进行了风险评估。结果表明,联苯肼酯在0.002 5~1.00 mg/L浓度范围内的线性关系良好,相关系数r为0.994 2。在0.020、0.20、2.0 mg/kg添加浓度下,绿茶中联苯肼酯的平均回收率分别为79.3%、88.6%、103.4%,相对标准偏差（RSD）分别为6.1%、5.9%、3.7%;红茶中联苯肼酯的平均回收率分别为79.3%、82.6%、103.3%,RSD分别为6.7%、4.5%、4.7%;鲜叶中联苯肼酯的平均回收率分别为91.1%、94.4%、91.0%,RSD分别为4.3%、3.8%、7.6%。方法检出限（LOD,S/N=3）为1.5 μg/kg,定量限（LOQ,S/N=10）为5 μg/kg。由于不同地区和时间的茶叶生长稀释作用、气候温度的不同,43%联苯肼酯悬浮剂在茶鲜叶生长中半衰期为1.4~2.9天;按照推荐剂量和1.5倍推荐剂量施药1~2次,结果表明,10天后成茶中的联苯肼酯残留量均小于5 mg/kg。根据风险评估结果,建议我国茶叶中联苯肼酯最大残留限量（MRL）值可设为5 mg/kg。     

25％氟硅唑·咪鲜胺水乳剂防治葡萄白腐病田间药效试验

1试验目的 明确试验药剂25％氟硅唑·咪鲜胺水乳剂对葡萄白腐病的防治效果、对作物的安全性及适宜的使用剂量和施药方法,为该药剂登记与推广提供依据。     

ICP-MS法测定土壤中钼、钴、锡、硒、铊、锶元素残留

目的:实验开发建立一种采用氢氟酸消解体系将土壤样品进行消解,电感耦合等离子体-质谱法检测钼、钴、锡、硒、铊、锶元素残留量的分析方法。方法 :准确称取粉碎后的样品0.5g,置消解罐中,盖紧消解罐内盖,置微波消解仪中消解,消解完毕后,赶酸,定容至50mL,上ICP-MS仪,内标法定量检测。结果:钼、钴、锡、硒、铊、锶分别在浓度为0.1～10、1.0～100、0.5～50、0.05～5、0.1～10和10～1000μg/L范围内具有良好的线性,相关系数R2均大于0.995,三水平加标平均回收率均在90%～110%之间,重复性(n=6)RSD均小于5%。结论:实验结果表明,该方法操作简便、检测结果准确度高,适用于土壤中极微量元素污染物残留的监测,为国家标准的起草提供技术参考。     

QuEChERS-LC-MS/MS测定姜油树脂、姜精油中8种农药残留及膳食风险评估

本研究建立了QuEChERS-液相色谱-串联四极杆质谱(LC-MS/MS)法测定姜油树脂、姜精油样品中噻虫嗪、吡虫啉、噻虫胺等8种农药残留,通过方法优化,选择乙腈-水-正己烷体系提取样品,QuEChERS方法净化提取液,在电喷雾离子源正离子模式下电离,多反应监测(MRM)模式下测定,并采用基质匹配标准曲线内标法进行定量分析。结果表明,8种农药在1～32μg/L浓度范围内的线性关系良好,相关系数(R²)均大于0.99,方法检出限和定量限分别为0.03～0.16、0.10～0.53 mg/kg; 3种不同加标水平下的回收率均在70%～119%之间,相对标准偏差(RSD)均小于20%。采用该方法测定实际样品,其中,噻虫嗪、吡虫啉、噻虫胺阳性样本的检出率较高,分别为56%、58%、52%,残留量大于1 mg/kg的样本量占比分别为12%、16%、10%,最高残留量分别为2.16、1.92、2.01 mg/kg,其他5种农药的检出率均低于20%。基于实际样品中农药残留中位值评估干姜片、姜精油和姜油树脂中噻虫嗪、吡虫啉、噻虫胺的慢性膳食摄入风险,评估结果远小于100%,表明农...     

50%乙草胺水乳剂对夏玉米田杂草的防除效果及对夏玉米安全性的研究

50%乙草胺水乳剂是新型玉米播后苗前土壤处理剂,研究采用随机区组设计,比较不同施药剂量50%乙草胺水乳剂对夏玉米田杂草的防除效果,及对夏玉米产量和安全性的影响.结果表明,50%乙草胺水乳剂80～160 g/0.067 hm2(制剂量)于播后苗前进行土壤处理,对北方夏玉米田主要禾本科杂草和阔叶杂草药后21～42 d株防效和鲜质量防效均达95%%以上,夏玉米产量比清水对照增加2.9%～5.7%,且对夏玉米安全,说明该药剂是防除夏玉米田主要杂草较理想的除草剂.     

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.     

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....     

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。     

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.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.