An innovative, flexible wall-pressure sensor array for unsteady flow conditions has been developed and evaluated in a turbulent shockwave-boundary layer interaction (SBLI) setup at Mach 2. Compared to the previous version, the new sensor's flexibility makes it easier to fit on different surfaces, while offering enhanced durability and improved sensitivity. The array comprises 18 circular sensors, each with a diameter of 3mm, fabricated using screen printing techniques from a thin piezoelectric PVDF film (thickness: 110 mu m). Remarkably, this sensor array achieves excellent spatial resolution while minimizing flow interference, all at a fraction of the cost associated with traditional dynamic pressure transducers.To validate its performance, the sensor array underwent dynamic calibration using a ball-drop impact test device. Subsequently, it was rigorously tested in a supersonic wind tunnel, demonstrating strong agreement with reference measurements obtained using a state-of-the-art Kulite pressure sensor. The resulting premultiplied power spectral density f . PSD distributions align closely with findings reported in existing literature. Notably, the low-frequency unsteadiness region beneath the separation shock foot (X* = 0) exhibits a Strouhal range of St = 0.03 - 0.05.

Shock wave boundary/layer interactions (SWBLIs) are critical in high-speed aerodynamic flows, particularly within supersonic regimes, where unsteady dynamics can induce structural fatigue and degrade vehicle performance. Conventional measurement techniques, such as pressure-sensitive paint (PSP), face limitations in frequency response, calibration complexity, and intrusive instrumentation. Similarly, MEMS-based sensors, like Kulite® sensors, present challenges in terms of intrusiveness, cost, and integration complexity. This study presents a flexible, lightweight polyvinylidene fluoride (PVDF) piezoelectric sensor array designed for high-resolution wall-pressure measurements in SWBLI research. The primary objective is to optimize low-frequency pressure fluctuation detection, addressing SWBLI’s need for accurate, real-time measurements of low-frequency unsteadiness. Fabricated using a double-sided screen-printing technique, this sensor array is low-cost, flexible, and provides stable, high-sensitivity data. Finite Element Method (FEM) simulations indicate that the sensor structure also has potential for high-frequency responses, behaving as a high-pass filter with minimal signal attenuation up to 300 kHz, although the current study’s experimental testing is focused on low-frequency calibration and validation. A custom low-frequency sound pressure setup was used to calibrate the PVDF sensor array, ensuring uniform pressure distribution across sensor elements. Wind tunnel tests at Mach 2 verified the PVDF sensor’s ability to capture pressure fluctuations and unsteady behaviors consistent with those recorded by Kulite sensors. The findings suggest that PVDF sensors are promising alternatives for capturing low-frequency disturbances and intricate flow structures in advanced aerodynamic research, with high-frequency performance to be further explored in future work.

加强京津双城的互联互动对于促进京津冀地区协同发展、提升整个地区的竞争力具有重要意义。为了细致刻画京津双城的要素对流特征，论文基于“双核结构”理论构建了京津双城联动的分析框架，并通过整合传统统计数据、手机信令大数据、企业联系大数据和调研资料等多源数据，从居民层面的人口对流、企业层面的经济要素对流、政府层面的合作平台共建3个方面开展双城联动分析。结果表明：京津具备了一定的业务合作规模，在各自的优势项目上互为支撑；北京在多数经济发展要素上的绝对优势造成了天津对北京的依赖程度更深，天津还需继续发力以增强其优势溢出能力；双城在功能定位和双城协同的认识上日趋清晰，但京津互联互通还需进一步细化功能协同、健全体制和机制，北京在功能疏解和与天津协同并辐射区域方面，天津在优化要素配置和产业环境、主动对接北京功能定位方面还存在改进空间。尤其是，天津作为门户城市、制造业强市和研发资源优势地区，在对北京的人才溢出、制造业承接、科技成果对接与转化、进出口货物的运输分担和对外联系功能等方面应发挥更大作用。研究结果可为未来京津双城的功能错位、优势互补、协调联动甚至同城化发展提供决策参考。

Our recent development of a wireless humidity sensor system embedded in incontinence products enables new sensor applications to diagnose and supervise geriatric diseases (i.e., age-related diabetes mellitus type II). The measurement of glucose in urine, so-called glucosuria, is an early indicator for an incipient diabetes mellitus disease, whose symptoms are often age-related but misjudged. In this paper, an incontinence glucose sensor is printed with biocompatible ink and Prussian blue as an electron mediator on foil and functionalized with immobilized glucose oxidase. Inkjet printing of multiple layers of Nafion prevents large interference substances from diffusing into the measuring electrode and allows precise adjustment of the linear working range, which is significantly different from blood glucose measurement. Performance tests show the potential to detect minimum glucose values and store the sensor over a prolonged period at room temperature. The printed glucose sensor can be embedded into the absorber material of incontinence products, where capillary forces transport the urine analyte to the detection area. An attached readout module with an integrated potentiostat measures the glucose concentration in urine, which is transmitted wirelessly with incontinence events and stored in a cloud service for further analysis by medical staff and care workers.

With the development of urban transportation in China, the space under the viaduct, as one of the important forms of urban space, begins to receive more and more attention from scholars. At present, the utilization of the space under the elevated bridges in China is still in the exploration stage, and the utilization of the space under the elevated bridges is still not fully explored, and the full utilization of the space under the bridges is of great significance to improve the efficiency of land use. Based on the review of cases and from the perspective of spatial function, this paper conducts an in-depth study on the spatial form under the urban viaducts in Changchun area, and proposes the idea of setting up a vegetable market under the viaducts in Changchun.

The implementation of a novel, cost-effective PVDF piezo-film sensor array for unsteady wall-pressure measurements in supersonic flows is introduced. With this type of technique, multiple local pointwise measurements can be taken simultaneously from a single thin foil without disturbing the flow field. The paper presents a detailed explanation of the design of the sensor array and of its signal conditioning system. The sensor array is tested in a turbulent incident shockwave/boundary layer interaction (SBLI) at Mach 2 and validated through favorable comparison with a classical Kulite piezoresistive transducer. The results of unsteady wall-pressure measurements also show good agreement with other SBLI studies already presented in the literature.

In this paper we present a microphone sensor for aerospace applications. The novel microphones can be integrated into large arrays for measuring unsteady pressure fluctuations underneath the turbulent boundary layer (TBL), which can be applied to predict the cabin noise excitation. The microphone array has a high spatial resolution due to the small distance between its microphone elements. The microphone sensor is featuring a very thin membrane created by a special technology combining SOI wafer bonding and thinning and TSV (Through Silicon Vias) for contacting from the backside. The membrane thickness is about $4 \mu \mathrm{m}$. The membrane has a small hole in the middle (diameter about $7 \mu \mathrm{m})$ drilled by using laser technique. The TSVs are etched in the carrier wafer or interposer by using a KOH or DRIE/BOSCH process.

Safety is a crucial issue in hydrogen energy applications due to the unique properties of hydrogen. Accordingly, a suitable hydrogen sensor for leakage detection must have at least high sensitivity and selectivity, rapid response/recovery, low power consumption and stable functionality, which requires further improvements on the available hydrogen sensors. In recent years, the mature development of nanomaterials engineering technologies, which facilitate the synthesis and modification of various materials, has opened up many possibilities for improving hydrogen sensing performance. Current research of hydrogen detection sensors based on both conservational and innovative materials are introduced in this review. This work mainly focuses on three material categories, i.e., transition metals, metal oxide semiconductors, and graphene and its derivatives. Different hydrogen sensing mechanisms, such as resistive, capacitive, optical and surface acoustic wave-based sensors, are also presented, and their sensing performances and influence based on different nanostructures and material combinations are compared and discussed, respectively. This review is concluded with a brief outlook and future development trends.

A novel capacitive sensor for measuring the water-level and monitoring the water quality has been developed in this work by using an enhanced screen printing technology. A commonly used environment-friendly conductive polymer poly(3,4-ethylenedioxythiophene):poly (styrenesulfonate) (PEDOT:PSS) for conductive sensors has a limited conductivity due to its high sheet resistance. A physical treatment performed during the printing process has reduced the sheet resistance of printed PEDOT:PSS on polyethylenterephthalat (PET) substrate from 264.39 Ω/sq to 23.44 Ω/sq. The adhesion bonding force between printed PEDOT:PSS and the substrate PET is increased by using chemical treatment and tested using a newly designed adhesive peeling force test. Using the economical conductive ink PEDOT:PSS with this new physical treatment, our capacitive sensors are cost-efficient and have a sensitivity of up to 1.25 pF/mm.

Due to the demand of low-cost sensor applications and new technologies for efficient production, the printing of functional inks is one of the most sustainable and fastest-growing markets in the electronic industry. This statement is confirmed by the "Roadmap for Organic and Printed Electronics", which predicts that the global market value of this sector will increase by about 50% to about 43 billion USD by 2020. The reason for this enormous growth is the continuous development of various nanomaterials, with the possibilities to bind smallest particles of a material in a solvent and to apply the resulting inks with different printing techniques on temperature-sensitive large substrates. These comparatively simple additive processes allow for example a combination of conductive polymers and inorganic materials, to manufacture cost-efficient electronic systems. This work presents the development of a 2D-printed photosensor for the detection of ultraviolet radiation in the wavelength range of 310 nm - 390 nm for wearable applications. This interdigitated electrode sensor can be completely realized by applying inkjet printing technology with nanoparticle-based inks. It detects electromagnetic radiation resistively. The semiconductor layer (ZnO-based) reacts on the UV radiation. Figure 1 shows a schematic representation of the sensor structure and figure 2 the printed sensor. Due to the transparency of zinc oxide in the visible range of the electromagnetic spectrum, the printed sensing material is marked with a red square.

In this paper we present a printed, fast, high-sensitive and cheap wireless incontinence sensor [...]

Anodic bonding technology is a well-established industrial technique, which is reported to be the most widely used MEMS packaging method. This Paper studies residual stress issue caused by different coefficients of thermal expansion (CTE) between silicon and glass during the anodic bonding process and its influence on MEMS-based sensors. For this purpose, SW-YY ® Glass from ASAHI is selected. Firstly, the SW-YY ® glass material is characterized in the bonding temperature range from 250°C to 500°C and voltage range from 400V-800V. Secondly, a MEMS based pressure sensor and two type glass substrates (SW-YY ® , Pyrex ® 7740) were fabricated and bonded to evaluate the stress issue. Results show that the offset of the pressure sensor introduced by mismatched CTE was reduced significantly with SW-YY ® glass than standard Pyrex ® ®7740 glass. The proposed method can be used to reduce the influence of the internal stress caused with bonding temperature and the mismatched CTEs for stress sensitive MEMS.

Due to the growing numbers of elderly people in the world, who suffer from incontinence and are in the need of care, technologies are necessary to increase the effectiveness of nursing staff and enhance the hygiene for humans to improve life quality. For this reason a low cost humidity sensor system printed onto the substrate of a diaper with the novel organic conductive ink PEDOT:PSS (Poly (3,4-ethylenedioxythio-phene):Poly(styrene sulfonate)) was developed in previous work [1]. The novel material PEDOT:PSS is still expensive because of rare use in research and market demand. Therefore a way for optimization of the sensor is aimed to print the sensor with less material, but at the same time with no loss of sensitivity. With this purpose, two theoretical models are developed. An analytic model with geometrical based calculations and a Finite Element Analysis (FEA) simulation model, for deeper understanding of electric field effects with focus on the total capacitance of the sensor. To verify these theoretical models a characterization measurement of manufactured samples of previous work [1] is made, to obtain a comparison between every experimental method. For the theoretical models the necessary material parameters are characterized.

We report observing a double broad Kondo-like zero bias conductance peak at low temperatures in individual suspended electrospun nanofibers Poly(methyl methacrylate)- multiwalled carbon nanotubes. This anomalous behavior is suppressed at higher temperatures. We attribute this to the existence of correlated double impurity system inside the nanofiber. From the results we calculate a Kondo-like temperature for the nanofiber to be ~31.7-34K.

Multiwalled carbon nanotubes with their superb mechanical properties are an unique filler material for polymer composites. Here, we present an investigation of mechanical properties of electrospun Poly-(methyl-methacrylate) multiwalled carbon nanotubes composite nanofibers. The method of electrospinning was used to fabricate suspended individual Poly-(methyl-methacrylate) multiwalled carbon nanotubes nanofibers. In order to reinforce the nanofibers, different high concentration of multiwalled carbon nanotubes were used. Transmission electron microscopy measurements reveal a successful filling of the nanofibers. The different types of nanofibers were deposited at 5i02 substrates. Which were previously etched, to create trenches for bend tests. Followed by fixing the nanofiber with a focus ion beam platinum deposition at the trench edges. An atomic force microscopy was used to perform the mechanical nanofiber bending tests over trenches. The results were compared with pristine Poly-(methylmethacrylate) nanofibers to nanofibers with 15 weight% and 20 weight% multiwalled carbon nanotubes composite fibers. We observed that pristine nanofibers have Young's modulus of 136 MPa, while for composite nanofibers with 15 weight% have 2.65 GPa and with 20 weight% have 6.06 GPa (at room temperature and air ambiance). This corresponds to an increase of Young's modulus of 19 fold between the pristine nanofibers and the 15 weight% of mutliwalled carbon nanotubes filled nanofibers. Therefore the increase of the Young's modulus compared between the pristine and the 20 weight% MWCNT filled nanofibers corresponds to 45 fold.