Hybrid Devices by Selective and Conformal Deposition of PtSe2 at Low Temperatures

2D materials display very promising intrinsic material properties, with multiple applications in electronics, photonics, and sensing. In particular layered platinum diselenide has shown high potential due to its layer-dependent tunable bandgap, low-temperature growth, and high environmental stability. Here, the conformal and area selective (AS) low-temperature growth of layered PtSe₂ is presented defining a new paradigm for 2D material integration. The thermally-assisted conversion of platinum which is deposited by AS atomic layer deposition to PtSe₂ is demonstrated on various substrates with a distinct 3D topography. Further the viability of the approach is presented by successful on-chip integration of hybrid semiconductor devices, namely by the manufacture of a highly sensitive ammonia sensors channel with 3D topography and fully integrated infrared-photodetectors on silicon photonics waveguides. The presented methodologies of conformal and AS growth therefore lay the foundation for new design routes for the synthesis of more complex hybrid structures with 2D materials.     

Production of fine lactose particles from organic solvent in laboratory and commercial-scale spray dryers

A laboratory spray dryer and a commercial dryer with a production rate 50 times greater, both using two-fluid nozzles, were used to dry the same formulation from organic solvent. Both dryers generated particles of similar size, with tight particle size distributions (span <2), which varied with atomization gas flow rate, liquid flow rate, and solids concentration. Small-scale results with an external mixing nozzle were fitted to a correlation based on literature recommendations. This also fitted well for the commercial dryer with external mixing, and an internal mixing nozzle gave a tighter size distribution. Hence, successful verification at scale has been achieved.     

Inverse determination of Johnson–Cook model constants of ultra-fine-grained titanium based on chip formation model and iterative gradient search

In this paper, a systematic approach on how to predict kinematic errors based on tolerance of machine tools’ guideways is introduced. Firstly, the truncated Fourier series function is applied to fit curve of guideways surface. Since geometric profile errors are regarded as a bridge between tolerance and kinematic errors of machine tools’ guideways, the mapping relationship between tolerance and geometric profile errors of machine tools’ guideways is formulated, and the mapping relationship between geometric profile errors and kinematic errors of guideways is established. Then, kinematic errors prediction model based on tolerance of guideways is subsequently proposed. Finally, simulation verification is conducted with this method. Simulation results show the range of the predicted kinematic errors (positioning error, y direction and z direction straightness error, roll error, pitch error, and yaw error) is 17.12 μm, 56.57 μm, 70.71 μm, 28.28 μrad, 141.42 μrad, and 113.14 μrad, respectively. In order to verify the feasibility and effectiveness of the presented method, a measuring experiment is carried out on guideways of a gantry-type five-axis milling machine tools by using a dual-frequency laser interferometer. The measured and identified discrete data can be fitted precisely by Fourier curve fitting method. The fitting results show the range of the measured kinematic errors is 16.96 μm, 59.43 μm, 68.63 μm, 28.65 μrad, 135.40 μrad, and 111.58 μrad, respectively. The maximum residual errors between the predicted and measured values of kinematic errors are 1.67 μm, 5.19 μm, 5.50 μm, 1.87 μrad, 9.81 μrad, and 7.07μrad, respectively. Comparing with the measured results of kinematic errors, residual errors are considerably small and can be neglected. Therefore, there is no doubt that this method is effective enough for predicting kinematic errors and can be used to replace the measurement of kinematic errors. In the design stage of machine tools, this approach is convenient for engineers to derive the distribution of kinematic errors. And its basic idea can be applied to other type of machine tools’ guideways.     

VEGFR-1 Overexpression Identifies a Small Subgroup of Aggressive Prostate Cancers in Patients Treated by Prostatectomy

The VEGFR-1 is suggested to promote tumor progression. In the current study we analyzed prevalence and prognostic impact of the VEGFR-1 by immunohistochemistry on a tissue microarray containing more than 3000 prostate cancer specimens. Results were compared to tumor phenotype, ETS-related gene (ERG) status, and biochemical recurrence. Membranous VEGFR-1 expression was detectable in 32.6% of 2669 interpretable cancers and considered strong in 1.7%, moderate in 6.7% and weak in 24.2% of cases. Strong VEGFR-1 expression was associated with TMPRSS2:ERG fusion status as determined by fluorescence in situ hybridization (FISH) and immunohistochemistry (p < 0.0001 each). Elevated VEGFR-1 expression was linked to high Gleason grade and advanced pT stage in TMPRSS2:ERG negative cancers (p = 0.0008 and p = 0.001), while these associations were absent in TMPRSS2:ERG positive cancers. VEGFR-1 expression was also linked to phosphatase and tensin homolog (PTEN) deletions. A comparison with prostate specific antigen (PSA) recurrence revealed that the 1.7% of prostate cancers with the highest VEGFR-1 levels had a strikingly unfavorable prognosis. This could be seen in all cancers, in the subsets of TMPRSS2:ERG positive or negative, PTEN deleted or undeleted carcinomas (p < 0.0001 each). High level VEGFR-1 expression is infrequent in prostate cancer, but identifies a subgroup of aggressive cancers, which may be candidates for anti-VEGFR-1 targeted therapy.     

Solar control with thermotropic layers

Innovative means to control the light and energy flux according to demand are desirable for transparent façades and façade elements. One possibility to achieve this is presented by switchable layers that change their optical properties, either actively or passively, according to different control parameters. In addition to inorganic coatings on glass, there are several organic thermotropic systems that can be integrated into façade glazing. Above a certain temperature, thermotropic layers change from a clear to a translucent, light-diffusing state, thus switching from a highly transmitting to a diffusely reflecting state. We shall describe the basic principles of these systems and present an overview of some of the existing prototype systems. Installation options will be discussed and the results of an application in a retrofitted building presented.     

New algorithms for approximate Nash equilibria in bimatrix games

We consider the problem of computing additively approximate Nash equilibria in non-cooperative two-player games. We provide a new polynomial time algorithm that achieves an approximation guarantee of 0.36392. We first provide a simpler algorithm, that achieves a 0.38197-approximation, which is exactly the same factor as the algorithm of Daskalakis, Mehta and Papadimitriou. This algorithm is then tuned, improving the approximation error to 0.36392. Our method is relatively fast and simple, as it requires solving only one linear program and it is based on using the solution of an auxiliary zero-sum game as a starting point. Finally we also exhibit a simple reduction that allows us to compute approximate equilibria for multi-player games by using algorithms for two-player games.     

Comparison of analysis methods for package-induced stresses on moulded Hall sensors

Due to the piezoresistive and the piezo-Hall effect in semiconductor materials, Hall sensors show a strong temperature dependency and also a drift when subjected to temperature cycles Manic et al. (2000). Four factors mainly influence the mechanical stress in the sensitive layer. These are the geometry of the device, the differences of the coefficients of thermal expansion of the package materials, the temperature-dependent material properties and the time-dependent, viscous material properties. The objective of this investigation was to determine the mechanical stress in a moulded Hall sensor during the packaging process by finite-element simulation in comparison to experimental methods. It is shown that after each process-step the mechanical stress in the sensitive layer changes over time depending on the absolute value and the rate of the temperature change. Measurements of the inverse bending radius of glued and moulded chips show good agreement to the simulations.

     

Using Ginkgo's memory accessor for improving the accuracy of memory-bound low precision BLAS

The roofline model not only provides a powerful tool to relate an application's performance with the specific constraints imposed by the target hardware but also offers a graphic representation of the balance between memory access cost and compute throughput. In this work, we present a strategy to break up the tight coupling between the precision format used for arithmetic operations and the storage format employed for memory operations. (At a high level, this idea is equivalent to compressing/decompressing the data in registers before/after invoking store/load memory operations.) In practice, we demonstrate that a “memory accessor” that hides the data compression behind the memory access, can virtually push the bandwidth-induced roofline, yielding higher performance for memory-bound applications using high precision arithmetic that can handle the numerical effects associated with lossy compression. We also demonstrate that memory-bound applications operating on low precision data can increase the accuracy by relying on the memory accessor to perform all arithmetic operations in high precision. In particular, we demonstrate that memory-bound BLAS operations (including the sparse matrix-vector product) can be re-engineered with the memory accessor and that the resulting accessor-enabled BLAS routines achieve lower rounding errors while delivering the same performance as the fast low precision BLAS.