The ongoing trend of robotics, automation, quality control and its combination are leading to new possibilities in the field of metrology. The improvements, especially in the handling and accuracy of ...collaborative robotics, are enabling new applications for automated high-resolution optical 3D measurements. This is the basis for the implementation of a pick-and-place solution for automatic surface texture measurements by replacing a high precision x-y stage with a collaborative robot. In this paper two different Focus-Variation setups are compared to evaluate the uncertainty using a certified standard and a real sample.
We present an optical measurement device for the complete 3D measurement of very small micro cutting tools with diameters down to 100μm and below. Such micro tools can be hardly measured by ...conventional devices such as tactile systems due to their complex geometry and small dimensions. The used optical device is based on the Focus-Variation principle which combines the small depth of focus of an optical system with vertical scanning to provide topographical and color information from the variation of focus. Full 360° measurements of the tools are automatically measured in a two step procedure. First, single measurements are performed from different directions all around the specimen with the aid of a motorized rotation unit. Then all single datasets are automatically aligned and merged to a full 360° dataset. Various measurement results are presented for milling cutters and drills including tools with diameters in the range of about 50μm. From the measured tools various parameters can be obtained including the major diameter, the core diameter or various angles. Additionally roughness measurements are provided on small cutting tools showing the versatility of the system for both form and roughness measurements.
Tool wear, caused by high machining temperatures, cutting speed or mechanical load, can have various characteristics. Current solutions for metrological quantification are limited with respect to ...their viewing dependency and user influence. Here, a measurement solution which is based on 3D focus variation measurements is presented. The quantification is carried out by the automatic evaluation of flank wear parameters (ISO 3685:1993, ISO 8688-1:1989) and plastic deformation impression and depression parameters on 3D dataset series. This allows the visualization and assessment of wear over a period of time and provides crucial information for the manufacturing and machining process.
Systems of three interacting particles are notorious for their complex physical behaviour. A landmark theoretical result in few-body quantum physics is Efimov's prediction of a universal set of bound ...trimer states appearing for three identical bosons with a resonant two-body interaction. Counterintuitively, these states even exist in the absence of a corresponding two-body bound state. Since the formulation of Efimov's problem in the context of nuclear physics 35 years ago, it has attracted great interest in many areas of physics. However, the observation of Efimov quantum states has remained an elusive goal. Here we report the observation of an Efimov resonance in an ultracold gas of caesium atoms. The resonance occurs in the range of large negative two-body scattering lengths, arising from the coupling of three free atoms to an Efimov trimer. Experimentally, we observe its signature as a giant three-body recombination loss when the strength of the two-body interaction is varied. We also detect a minimum in the recombination loss for positive scattering lengths, indicating destructive interference of decay pathways. Our results confirm central theoretical predictions of Efimov physics and represent a starting point with which to explore the universal properties of resonantly interacting few-body systems. While Feshbach resonances have provided the key to control quantum-mechanical interactions on the two-body level, Efimov resonances connect ultracold matter to the world of few-body quantum phenomena.
Mutations in the chromodomain helicase DNA-binding 8 (CHD8) gene are a frequent cause of autism spectrum disorder (ASD). While its phenotypic spectrum often encompasses macrocephaly, implicating ...cortical abnormalities, how CHD8 haploinsufficiency affects neurodevelopmental is unclear. Here, employing human cerebral organoids, we find that CHD8 haploinsufficiency disrupted neurodevelopmental trajectories with an accelerated and delayed generation of, respectively, inhibitory and excitatory neurons that yields, at days 60 and 120, symmetrically opposite expansions in their proportions. This imbalance is consistent with an enlargement of cerebral organoids as an in vitro correlate of patients’ macrocephaly. Through an isogenic design of patient-specific mutations and mosaic organoids, we define genotype-phenotype relationships and uncover their cell-autonomous nature. Our results define cell-type-specific CHD8-dependent molecular defects related to an abnormal program of proliferation and alternative splicing. By identifying cell-type-specific effects of CHD8 mutations, our study uncovers reproducible developmental alterations that may be employed for neurodevelopmental disease modeling.
Display omitted
•CHD8-mutant cerebral organoids recapitulate a macrocephaly-like phenotype•Proliferation and differentiation dynamics are affected by CHD8 mutations•CHD8 haploinsufficiency disrupts neurodevelopmental trajectories•mRNA processing in post-mitotic neurons is altered in CHD8 mutants
Using cerebral organoids, Villa et al. show that CHD8 haploinsufficiency disrupts neurodevelopmental trajectories by promoting an accelerated generation of inhibitory neurons and a delayed production of excitatory neurons with a temporally restricted cell-type-specific effect on proliferation of radial glial cells.
The use of concentrated hydrogen peroxide as an agent which etches TiW is well known in the metals industry. Although hydrogen peroxide is used in most semiconductor manufacturing processes, its' ...application as an etchant for TiW has been limited. Since some Micro-Rel product uses a composite metallization scheme containing a TiW/AlSiCu/TiW sandwich, the bonding pad etch process must include a TiW removal step. Without this step, a residual TiW layer is left on the metal pads causing wire adhesion problems (non-sticks) during the wire bonding processes. Current plasma etch techniques still leave a TiW residue on the aluminum surface. The hydrogen peroxide clean was instituted to minimize the presence of the TiW residue. By inserting this clean as the last step of the pad masking module, a cleaner metal surface was developed. To test the new process, wire pulls were done on product by two separate business units within Medtronic. Results from both areas showed no lifts. Surface analyses of metal bond pads treated with hydrogen peroxide shows a significant decrease in the concentrations of metallic oxides and tungsten. The SEM images of bonding pads show no loss in metal thickness and the metal surface is relative smooth with no trace of TiW visually evident.
We developed a rapid method to remove the native mouse thymus from NSG mice, which allowed us to compare the behavior of human immune cells in the presence or absence of human T cells in human immune ...system mice. Removing the native mouse thymus is critical for studies of human thymopiesis in grafted thymic tissue in humanized mice.
PDF
