基于MR的智能产线学具开发与应用——以SMT电路表面贴装产线为例

针对中心现有电路表面贴装技术(Surface MountedTechnology,SMT)教学环节认知负载高的问题,设计基于混合现实(Mixed Reality,MR)技术的智能产线教辅系统。目前,产线以自动化生产为主,学生无法直接观察其生产工艺及过程,后台数据不易呈现。通过MR技术将设备内部的运作状态及数据以三维影像投射在实体表面,为学生构建一种新的交互载体。通过将SMT产线的核心工艺数据从“黑盒子”中拿出来,帮助学生理解电路产品的制作原理、工艺过程等核心知识。通过“基于MR的SMT产线智能辅助教学系统”的开发与应用实例,介绍了基于本智能制造教学系统的需求分析、功能设计及开发与实施路线。

回流焊工艺对SMT器件热翘曲的影响

集成电路正在向小型化、高集成度的方向发展,回流焊工艺已成为其组装过程中的关键技术。在回流焊过程中集成电路容易发生热翘曲现象。采用阴影云纹法对PBGA1296、PBGA1024器件在不同回流焊温度、升降温速率的回流焊工艺下的热翘曲进行测量,在此基础上通过建模仿真对实验结果进行分析。结果表明,采用表面贴装技术(SMT)的BGA器件的热翘曲会随着回流焊温度的升高而增大,回流焊升降温速率较快同样会导致严重的热翘曲。实验结果与仿真结果高度一致,进而验证了仿真模型的准确性和有效性。采用实验结合有限元分析的方法为改善集成电路热翘曲提供了参考。

Bioaccumulation and Biodegradation of Sulfamethazine in Chlorella pyrenoidosa

Intensive use of sulfamethazine(SM_2) in aquaculture has resulted in some detrimental effects to non-targeted organisms. In order to assess its potential ecological risk, it is crucial to have a good understanding on the bioaccumulation and biodegradation of SM_2 in Chlorella pyrenoidosa. The microalgae were treated with 2, 4, and 8 mg L^(-1) of sulfamethazine for 13 days, respectively, showing that the inhibition effects of sulfamethazine on the growth of Chlorella pyrenoidosa increased progressively as the concentrations of sulfamethazine increasing from 2 to 8 mg L^(-1). The peak concentrations of sulfamethazine accumulated in C. pyrenoidosa were 0.225, 0.325, and 0.596 ng per mg FW on day 13 for three treatment groups, respectively, showing a great ability to deplete sulfamethazine from the culture media. On day 13, the percentages of biotic degradation were 48.45%, 60.21% and 69.93%, respectively. The EC_(50) of 10.05 mg L^(-1) was derived which showed no significant risk for C. pyrenoidosa with a calculated risk quotient < 1. The activities of superoxide dismutase and catalase increased progressively in response to sulfamethazine and showed a positive correlation to the treatment concentrations. The highest superoxide dismutase activity was achieved at the concentration of 8 mg L^(-1) after 2 d of exposure, which was 1.89 folds higher than that of the control. The activity of catalase has a similar pattern to that of superoxide dismutase with the maximum activity achieved at day 2, which was 3.11 folds higher compared to that of the control. In contrast to superoxide dismutase and catalase, the maximum glutathione S-transferase activity was observed at day 6, showing 2.2 folds higher than that of the control.

基于SMT单片机的双轴太阳能智能追光系统的设计

为提高太阳能发电效率,文章设计了一种基于SMT单片机的双轴太阳能智能追光系统。系统通过光敏器件采用双轴跟踪方式根据太阳光照强度实时调整光伏电池板的方向,使光伏板接收太阳辐射的效率最高。系统实时采集光照强度参数并显示,由单片机控制电机“智慧”追踪太阳,亦可通过按键切换为手动模式控制步进电机四向翻转。若光照不够,可以通过充电器为系统充电使其正常工作。

Survey of Tetracyclines, Sulfonamides, Sulfamethazine, and Quinolones in UHT Milk in China Market

This study surveyed 180 samples of ultra high temperature （UHT） milk of four top Chinese dairy brands collected in the 25 cities in China in June 2011, and assessed their contamination with antibiotics, using the ELISA method. The percentages of tetracyclines, sulfonamides, sulfamethazine, and quinolones detected in the samples were 0, 16.7, 40.6, and 100%, respectively. The maximum concentrations of the tetracyclines, sulfonamides, sulfamethazine and quinolones in UHT milk samples were 〈1.5, 26.2, 22.6, and 58.8 μg kg-1, respectively. None of the samples exceeded the maximum residue levels （MRLs） for these four veterinary drugs, according to the regulations set by China, the European Union （EU） and the Codex Alimentarius Commission （CAC）.

Preparation and Characteristic Identification of Monoclonal Antibody Against Sulfamethazine

Two artificial antigens were synthesized successfully by diazotizing method, sulfamethazine（SM2）-human serum albumin （HSA） was used for the immunogen, and SM2-ovalbumin（OVA） was used for the coating antigen. The coupled reaction was successful by confirmation of the ultraviolet scanning spectrometer, and the conjugation ratio of SM2 with HSA and OVA was 9：1 and 15：1, respectively. Using cell-fusion and limiting dilution method to reclone 5 times to get 3 hybridoma strains, which could stably secret monoclonal antibody （Mab）, named CBT, BC4 and BB12. The subtype of BC4 Mab was IgG1 and chain, the molecular weight was 162 ku, the numbers of chromosomal were about 90, the affinity constant was 6.1 × 10^12 M^-1. No cross reactivity was seen between the Mab and the other 4 sulfonamides, as well as the 2 carries proteins. The Mab antibody had excellent stability.

Photocatalytic degradation of sulfamethazine by graphitic carbon nitride-modified zinc molybdate:Effects of synthesis method on performance, degradation kinetics,and mechanism

In the present study,zinc molybdate(β‐ZnMoO4)and graphitic carbon nitride(g‐C3N4)‐modifiedβ‐ZnMoO4(β‐ZnMoO4/g‐C3N4)were prepared to decontaminate aqueous solutions from the antibiotic sulfamethazine(SMZ).Our results revealed that the hydrothermal synthesis method greatly influenced the photocatalytic activity of the resultant catalysts.The pristineβ‐ZnMoO4samples obtained under more intensive synthesis conditions(24h at280°C)showed higher photocatalytic activity than that prepared for12h at180°C(denotedβ‐ZnMoO4‐180).In the case of in situ hydrothermal synthesis ofβ‐ZnMoO4/g‐C3N4,a surface‐modified sample was only obtained under the reaction conditions of180°C for12h.Compared with the sheet‐likeβ‐ZnMoO4‐180sample,theβ‐ZnMoO4‐180/g‐C3N4composite showed enhanced photocatalytic activity for the degradation of SMZ.By contrast,the hydrothermal reaction at280°C caused the gradual decomposition of g‐C3N4.It is believed that the structural incorporation of g‐C3N4intoβ‐ZnMoO4at280°C might disrupt the crystal growth,thereby deteriorating the performance of the composite catalysts formed at this temperature.For the composite catalysts prepared by the ultrasonic method,a remarkable increase in the degradation rate of SMZ was only observed at a high g‐C3N4content of8mol%.The photocatalytic degradation of SMZ byβ‐ZnMoO4‐180/g‐C3N4composite catalysts followed pseudo‐first‐order kinetics.Further study of the photocatalytic mechanism revealed that holes and superoxide radicals were the dominant oxidative species in the photodegradation process.The enhanced photocatalytic performance of the composites was attributed to the higher separation efficiency of the photogenerated electron‐hole pairs at heterogeneous junctions.The degradation intermediates of SMZ were detected by liquid chromatography‐mass spectrometry,from which plausible reaction pathways for the photodegradation of SMZ were proposed.Our results indicated that the synthesis method for g‐C3N4composites should be carefully selected to achieve superior photocatalytic performance.

课程思政理念下《SMT技术》课程改革策略研究

以培养高素养、强技能人才为抓手,践行立德树人、侧重课程思政建设,是新时期下高等职业教育发展之重要路径。表面组装技术(Surface Mount Technology,SMT)课程中涵盖了大量的思政教育元素,通过深入分析、挖掘这些内容,并开展相应教学活动,可以持续强化学生核心竞争力,进一步深化课程教学改革。因此,学校和课程教师需要结合全新育人理念内涵,不断提升师资力量、创新教育模式、加强校企合作,从而构建新时期下的育人格局。本文就课程思政理念下《SMT技术》课程教学改革进行研究,并对此提出相应看法。

SMTLOC:基于多源频谱的SMT求解器缺陷定位

SMT求解器作为重要的基础软件,其存在的缺陷可能会导致依赖于它的软件功能失效,甚至带来安全事故.然而,修复SMT求解器缺陷是一个十分耗时的任务,因为开发者需要花费大量的时间和精力来理解并找到缺陷的根本原因.虽然已有许多软件缺陷定位方面的研究,但尚未有系统的工作研究如何自动定位SMT求解器缺陷.因此,提出一种基于多源频谱的SMT求解器缺陷定位方法SMTLOC.首先,对于给定的SMT求解器缺陷,SMTLOC提出一种枚举算法,用以对触发该缺陷的公式进行变异,从而生成一组不触发缺陷,但与触发缺陷的公式具有相似执行路径的证人公式.然后,SMTLOC根据证人公式的执行路径以及SMT求解器的源码信息,提出一种融合覆盖频谱和历史频谱的文件可疑度计算方法,从而定位可能存在缺陷的文件.为了验证SMTLOC的有效性,收集60个SMT求解器缺陷.实验结果表明,SMTLOC的缺陷定位效果明显优于传统的频谱缺陷定位方法,SMTLOC可以将46.67%的缺陷定位在TOP-5的文件内,定位效果提升了133.33%.

Imaging Array SPR Biosensor Immunoassays for Sulfamethoxazole and Sulfamethazine

A homemade array surface plasmon resonance （SPR）-based imaging biosensor was used to develop sensitive and fast immunoassays to determine sulfamethoxazole （SMOZ） and sulfamethazine （SMT） in buffer. Two conjugations of sulfonamide-bovine serum albumin （BSA） were separately immobilized on two different rows of the array chip with one row as reference. The immobilization was carried out in the instrument to monitor the quantity of the conjugations immobilized. The antibody mixed with the sulfonamide in the buffer was injected over the surface of the chip to get a relative response which was inversely proportional to the concentration of the sulfonamide in the PBS buffer. Two calibration curves were constructed and the limit of detection for sufamethoxazole in buffer was 3.5 ng/mL and for sulfamethazine 0.6 ng/mL. The stability and specificity of the antibody were also studied. The monoclonal antibody did not bind with BSA.

Study on ELISA for detection of sulfamethazine residues

In this study, various factors of ELISA for detection of sulfamethazine residues were explored, the coating antigen was diluted to 1：400, the best coating condition was at 4℃ overnight, the working concentration of HRP-IgG enzyme conjugate was 1 ： 7 000. The pre-incubation time and incubation time was 30 min and 120 min, respectively, the substrate solution working time was 20 min. Two moL · L^-1 H2SO4 was used to stop the reaction and checked. A standard curve of direct competitive ELISA had been established to detect the sulfamethazine residues in milk. The detection limit of this method was 1.97 ng · mL^-1. The mean concentration of sulfamethazine required to inhibit 30% antibody was 7.1 ng · mL^-1. The linear range of the detection was 5-200 ng · mL^-1. The recovery ratio was between 73.20% and 91.16%. The CV% of within array and between arrays was less than 10%.

基于价值流的SMT贴片生产车间流程优化

本文以A公司SMT贴片生产流程为研究对象,运用价值流图析技术对其进行精益改善,并提出了改善措施。收集生产车间数据,绘制现状价值流图识别不增值环节,分析流程中的浪费进行改善,基于精益生产的原则,以连续流生产为目标导向,以未来价值流图为改善标准,通过方案的实施让企业价值流朝着理想化方向发展。

Removal of Sulfamethazine by Corn Biochars from Aqueous Solution:Sorption Mechanisms and Efficiency

Sorption mechanisms of sulfamethazine(SMT)in different pH solutions are complicated.It has not been sufficiently investigated to enhance removal of SMT from alkalescent aqueous solution.In this study,sorption isotherms and kinetics of SMT by corn biochars pyrolyzed at 300℃ and 600℃(300C,600C)under diverse pH conditions were compared.In order to improve the sorption efficiency of SMT from alkalescent aqueous solution,the biochar 300C was modified by acid or base.Different mathematic models were used to describe sorption driving force and sorption process.Results showed that the biochar 300C possessed more amorphous organic carbon and polar functional groups,which led to a higher sorption capacity than biochar 600C.The sorption rate of biochar 300C was greater than 600C under diverse pH as the physisorption of 300C outweighed 600C.The SMT presented stronger hydrophobicity at pH 5 and higher electrostatic repulsion at pH 1 or 8,which resulted in a higher combining capacity of SMT with both biochars at pH 5 than other pH values.In addition,the acid modified biochar had better removal effect on SMT than alkali at pH solution around 8.The research provides a theoretical basis for the removal of SMT from alkalescent aqueous solution.

基于改进迭代局部搜索的多SMT产线多目标优化

针对多PCB订单在多条SMT生产线上的生产调度问题,同时考虑SMT生产线治具约束、生产线停线计划约束,建立以最小化总拖期为主目标和最大完工时间为子目标的数学模型。基于问题特性,提出了一种基于问题邻域知识的多目标迭代局部搜索算法求解问题模型,设计带约束的局部搜索在优化主目标函数时,将子目标函数限制在一定的允许量内,设计4种局部搜索算子局部寻优,扰动产生多个扰动解取Pareto最优解作为下一次的迭代解,增加算法全局搜索能力。在相同的计算资源下,对问题规模大于100×5(PCB订单数×SMT生产线数)的测试集,所提出的算法在主目标总拖期优化上相比传统迭代局部搜索算法提升35%以上,验证了算法的有效性。

机器视觉在SMT型信号继电器检测封装中的应用

在电路板表面贴装(SMT)的生产工艺中,为保证贴装质量,对SMT型信号继电器的外观有较高的要求。机器视觉具有检测效率高、稳定性好等特点,采用机器视觉替代人工对SMT型信号继电器进行外观检测,降低人工成本,提高生产效率和产品质量,完善第三代和第四代宏发SMT型信号继电器自动生产技术。该文介绍机器视觉在SMT型信号继电器检测封装过程中的场景应用,并对机器视觉的前景进行展望。

基于SMT的ACORN v3算法的差分分析

ACORN v3算法是凯撒竞赛胜出的认证加密算法之一。本文考虑状态更新过程中非线性函数对状态差分传递的影响,给出ACORN v3算法非线性函数的差分传递模型,通过分析ACORN v3算法解密验证阶段的状态更新,重新评估了算法抗差分伪造攻击的能力,将ACORN v3算法认证阶段的有效差分伪造攻击轮数的上界从86轮提升到了102轮。本文对该算法初始化阶段分析,在选择IV的攻击条件下,通过在IV处注入差分,给出ACORN v3算法初始化阶段的差分分析,对模型求解情况进行分类,以概率1得到初始化阶段461轮输出密钥流的差分区分器,选取了10对满足输入差分的IV,以99.9%的成功率将初始化461轮的ACORN算法和随机置换产生的密钥流区分开来。

SMT回流焊工艺分析及其温控技术的实现

随着电子器件微型化及表面贴装技术(Surface Mounted Technology,SMT)的发展,热风回流焊机在电子制造业中的应用日益广泛。然而,在回流焊过程中,由于被控参数的非线性、不确定性等因素,传统的比例-积分-微分(Proportion Integral Differential,PID)控制器难以取得满意的控制效果。针对SMT回流焊工艺的特点,分析温控技术在回流焊过程中的重要性,并探讨温控技术的实现方法。设计一整套多中央处理器(Central Processing Unit,CPU)嵌入式硬件系统,并使用改进PID控制算法控制热风回流焊机。针对回流焊机温区多、人工参数整定效率低的问题,研究PID参数自整定的方法。在改进PID控制算法的基础上,提出上位机插值模糊PID控制算法。所提出的温控技术能够有效提升回流焊质量,满足现代电子制造业的高精度要求。

SMT锡膏冷焊缺陷分析及解决策略研究

表面贴装技术(SMT)贴片指在印刷电路板(PCB)基础上二次加工的系列工艺流程的简称,在SMT贴片中,锡膏是此项技术应用中使用的关键辅料。在SMT贴片实际操作过程中,焊接时常出现的冷焊现象也和锡膏的使用有着密不可分的联系。基于此,文章从锡膏材料构成、锡膏材料在SMT贴片中应用的参数设置出发,结合锡膏焊接的实际情况进行观察研究,通过对比使用锡膏之后不同材质表面PCB焊接情况,分析得出SMT锡膏冷焊缺陷出现的根本原因,并根据缺陷原理,提出技术实际应用中有效规避冷焊缺陷的技术策略,以此让电子产品使用中的可靠性得到进一步提升,促进我国电子产业技术发展。

SMT生产线的智能质量优化技术应用研究

随着电子产业的飞速发展,电子应用技术正在向着智能化、多媒体化以及网络化的方向发展,此时SMT技术应运而生。早在90年代相关科学技术已经足以支撑SMT贴装技术的发展与普及。时至今日,SMT技术已经成为电子产品贴装工艺技术的主流发展趋势。虽然SMT的工艺环节较为简单,但是每个环节的工作情况都会直接影响到最终的工艺质量,所以要切实提升SMT工艺的质量就必须从细节入手。本文阐述了SMT质量检测分析方式,介绍了SMT工艺技术,剖析了影响SMT工艺质量的关键环节与因素,并对SMT生产线的智能数据采集技术进行了探讨,最后提出了提升SMT工艺质量的方案与建议,以期为业内研究提供参考。

新型SMT印刷网版的研制和应用

采用镁合金材料一次压铸成型制作表面贴装技术(SMT)印刷网版网框,改进网框内部结构设计,提高网框强度。采用聚酰亚胺薄膜对网框进行张膜,取代传统聚酯纤维(涤纶)材质网纱张纱工艺,减少印刷时弹性形变,从而提高网版印刷精度。研究印刷面超疏水微纳结构及表面钝化对激光切割网版钢片表面光洁度和耐刮擦强度的影响,使SMT印刷网版印刷精度更高,机械强度更强,使用寿命更长。