Automated zebrafish chorion removal and single embryo placement: optimizing throughput of zebrafish developmental toxicity screens

The potential of the developing zebrafish model for toxicology and drug discovery is limited by inefficient approaches to manipulating and chemically exposing zebrafish embryos-namely, manual placement of embryos into 96- or 384-well plates and exposure of embryos while still in the chorion, a barrier of poorly characterized permeability enclosing the developing embryo. We report the automated dechorionation of 1600 embryos at once at 4 h postfertilization (hpf) and placement of the dechorionated embryos into 96-well plates for exposure by 6 hpf. The process removed ≥95% of the embryos from their chorions with 2% embryo mortality by 24 hpf, and 2% of the embryos malformed at 120 hpf. The robotic embryo placement allocated 6-hpf embryos to 94.7% ± 4.2% of the wells in multiple 96-well trials. The rate of embryo mortality was 2.8% (43 of 1536) from robotic handling, the rate of missed wells was 1.2% (18 of 1536), and the frequency of multipicks was <0.1%. Embryo malformations observed at 24 hpf occurred nearly twice as frequently from robotic handling (16 of 864; 1.9%) as from manual pipetting (9 of 864; 1%). There was no statistical difference between the success of performing the embryo placement robotically or manually.     

EFFECTS OF SPECIFIED BLANK SIZE ON BODY WRINKLING DURING HYDRODYNAMIC DEEP DRAWING OF TAPERED RECTANGULAR BOX

1.~nonHydridapawhcdeepdrawing(HDD)belongstothefieldofsheetmetalfoeingandcanbeaPPliedinthefieldofautomotive,aerospace,drilitaryindustryetc.Ithasbeenrecognizedwidelyintheworld["'j.Fig.Ishowsitsprinciple:TheliqUidthatisfilledinthe~ngdiecavitywillbepressedwhenthepunchgoesdownsothattheeffectoffrictionkeepingandoverflowlubricatingcanbeformed,astherestilt,thefoeinglicitofsheetmetalwillbeimprovedareailvandthegualitVofthefinishedpartswillbeup~ed.BecauseofmanyadvantagesofHDDprocees,ithasbeenwidelys…     

自动剪切生产线的PLC控制系统设计

为使自动剪切生产线设备协调运行,设计其控制系统。系统以可编程控制器（PLC）为核心,还包括触摸屏、变频器、伺服驱动器/伺服电机等部件。送料长度在触摸屏上设置,PLC根据设定值计算出脉冲数后向伺服驱动器发送,控制伺服电机送料,从而实现精确的伺服定位,其定位精度可达1m±0.01mm。     

铝-镁-硅系合金的挤压参数及机械性能

虽然铝-镁-硅系合金(AA6×××系)是最经常使用的挤压材料,其产量约占全世界挤压材的70％～80％,然而探讨此类合金挤压参数的文献却很少。所以本文的目的不是优选合金,而是研究铝-镁-硅系合金的技术应用范围。 1.坯锭生产连续铸造出圆锭,再锯成12个坯锭。坯锭的直径为123毫米,长度为500毫米。其中一半在铸态下挤压,另一半在580℃均匀化16小时(保温时间)随后空冷后挤     

喷射超高韧性水泥基复合材料的力学性能研究

超高韧性水泥基复合材料(Ultra High Toughness Cementitious Composites,UHTCC)是一种具有良好变形性能、裂缝控制能力和耐久性能的新型水泥基复合材料,特别适用于大坝、灌渠等水工结构的加固和修补。然而现有UHTCC材料在喷射施工过程中存在难泵送、易堵管和与结构面粘结性能差等问题,难以实现大面积快速施工,制约了该材料在实际工程中的推广和应用。本文研制出了一种可连续喷射、回弹率低的UHTCC材料,同时保证了喷射过程中纤维的均匀分散,材料硬化后仍具备拉伸应变硬化和多缝开裂特征。喷射UHTCC的压缩性能、直接拉伸性能和抗折性能试验结果显示,该材料28 d龄期抗折强度为10.30 MPa,拉伸强度为2.33 MPa,拉伸应变稳定在1.5%以上,具有延性破坏特征和良好的控裂性能,其性能可满足一般水工结构的表面加固和修补要求。     

带初始损伤混凝土的动态抗压性能研究

对65个直径为68 mm的混凝土圆柱体试件进行试验分析,系统研究了不同初始损伤程度的混凝土试件在冲击荷载作用下的动态抗压特性。通过对混凝土试件预加不同的静态荷载,从而在试件内产生不同程度的初始损伤;利用SHPB设备进行不同速率下的冲击试验,研究初始损伤程度对混凝土动态抗压强度、应力应变关系以及破坏模式的影响。试验结果表明,初始损伤对混凝土动态抗压强度产生重要影响,其影响程度与混凝土试件的初始损伤程度密切相关,损伤程度在阈值以下时对混凝土的动态抗压强度影响较小,超过阈值时影响显著;随应变率增加,带损伤混凝土的动态抗压强度显著提高;含水率的增加降低了带初始损伤混凝土动态抗压性能。基于试验结果,提出了综合考虑初始损伤程度影响和应变速率效应的抗压强度预测模型。     

DBST: a lightweight block cipher based on dynamic S-box

IoT devices have been widely used with the advent of 5G. These devices contain a large amount of private data during transmission. It is primely important for ensuring their security. Therefore, we proposed a lightweight block cipher based on dynamic S-box named DBST. It is introduced for devices with limited hardware resources and high throughput requirements. DBST is a 128-bit block cipher supporting 64-bit key, which is based on a new generalized Feistel variant structure. It retains the consistency and significantly boosts the diffusion of the traditional Feistel structure. The SubColumns of round function is implemented by combining bit-slice technology with subkeys. The S-box is dynamically associated with the key. It has been demonstrated that DBST has a good avalanche effect, low hardware area, and high throughput. Our S-box has been proven to have fewer differential features than RECTANGLE S-box. The security analysis of DBST reveals that it can against impossible differential attack, differential attack, linear attack, and other types of attacks.     

Measurement-based modeling of contact forces and textures for haptic rendering

Haptic texture represents the fine-grained attributes of an object's surface and is related to physical characteristics such as roughness and stiffness. We introduce an interactive and mobile scanning system for the acquisition and synthesis of haptic textures that consists of a visually tracked handheld touch probe. The most novel aspect of our work is an estimation method for the contact stiffness of an object based solely on the acceleration and forces measured during stroking of its surface with the handheld probe. We establish an experimental relationship between the estimated stiffness and the contact stiffness observed during compression. We also measure the height-displacement profile of an object's surface enabling us to generate haptic textures. We show an example of mapping the textures on to a coarse surface mesh obtained with an image-based technique, but the textures may also be combined with coarse surface meshes obtained by manual modeling.