Thermistor-based micro-electromechanical system (MEMS) vacuum sensors are widely used for vacuum monitoring. It is usually operated in constant temperature (CT) mode because this mode is more suited for rough vacuum regime and could avoid potential damage caused by overheating. However, the CT circuit will suffer from temperature drift, so it is necessary to compare and optimize existing temperature drift suppression methods. In this study, the thermal equivalent circuit method is used to set up the macromodel of thermistor-based MEMS vacuum sensors, the cosimulation with three CT circuits is carried out and compared using Advanced Design System software, and an optimized temperature drift suppression CT circuit is designed. Experiment results obtained by the optimized temperature drift suppression CT circuit show that the average error between simulation and experiment in response voltage for the vacuum pressure range of 3.75x10(-3) to more than 1000 torr is 3.003%, and the response voltage at atmospheric pressure and 3.75x10(-3) torr is separately +/- 0.694% and +/- 2.949%, respectively, when the ambient temperature ranges from -20 C-degrees to 80 C-degrees.

Inflammatory bowel disease (IBD) is a chronic and recurrent intestinal disease, and has become a major global health issue. Individuals with IBD face an elevated risk of developing colorectal cancer (CRC), and recent studies have indicated that mitochondrial dysfunction plays a pivotal role in the pathogenesis of both IBD and CRC. This review covers the pathogenesis of IBD and CRC, focusing on mitochondrial dysfunction, and explores pharmacological targets and strategies for addressing both conditions by modulating mitochondrial function. Additionally, recent advancements in the pharmacological modulation of mitochondrial dysfunction for treating IBD and CRC, encompassing mitochondrial damage, release of mitochondrial DNA (mtDNA), and impairment of mitophagy, are thoroughly summarized. The review also provides a systematic overview of natural compounds (such as flavonoids, alkaloids, and diterpenoids), Chinese medicines, and intestinal microbiota, which can alleviate IBD and attenuate the progression of CRC by modulating mitochondrial function. In the future, it will be imperative to develop more practical methodologies for real-time monitoring and accurate detection of mitochondrial function, which will greatly aid scientists in identifying more effective agents for treating IBD and CRC through modulation of mitochondrial function.

The Seebeck coefficient of thermopile infrared (IR) sensors is a crucial parameter. The ability to rapidly and insitu extract the Seebeck coefficient across a wide temperature range is advantageous for assessing the impact of temperature on sensor's performance. In this study, specific sets of current excitations are used, the exothermic and endothermic temperature changes caused by Peltier effect are offset, and the Seebeck coefficient of sensor over a wide temperature range (300-600 K) is extracted from Joule heat by measuring the resistance of sensor. The effectiveness of this method is evaluated by a thermopile IR sensor. The maximum relative error between the results obtained from this method and specialized instrument does not exceed 9 %.

Thermopile infrared (IR) sensors based on the thermoelectric effect are widely applied in industrial and civil fields. Researchers urgently need to develop a technique for in situ online extraction of the sensor's thermal parameters, in order to allow for better analysis of the sensor's performance and to improve its structure. In this work, a pulse-voltage-based self-test method is proposed. The pulse voltage can be generated easily, and only a few data points are required, with simple data processing. The measured results are close to the theoretical values and results from the constant current method proposed in another paper, thus indicating that our method is effective and accurate. In addition, it has strong significance for array testing.

Targeted therapies in cancer treatment can improve in vivo efficacy and reduce adverse effects by altering the tissue exposure of specific biomolecules. However, there are still large number of target proteins in cancer are still undruggable, owing to the following factors including (1) lack of ligand-binding pockets, (2) function based on protein-protein interactions (PPIs), (3) the highly specific conserved active sites among protein family members, and (4) the variability of tertiary docking structures. The current status of undruggable targets proteins such as KRAS, TP53, C-MYC, PTP, are carefully introduced in this review. Some novel techniques and drug designing strategies have been applicated for overcoming these undruggable proteins, and the most classic and well-known technology is proteolysis targeting chimeras (PROTACs). In this review, the novel drug development strategies including targeting protein degradation, targeting PPI, targeting intrinsically disordered regions, as well as targeting protein-DNA binding are described, and we also discuss the potential of these strategies for overcoming the undruggable targets. Besides, intelligence-assisted technologies like Alpha-Fold help us a lot to predict the protein structure, which is beneficial for drug development. The discovery of new targets and the development of drugs targeting them, especially those undruggable targets, remain a huge challenge. New drug development strategies, better extraction processes that do not disrupt protein-protein interactions, and more precise artificial intelligence technologies may provide significant assistance in overcoming these undruggable targets.

To adapt to the development trend of high-spatial-resolution of uncooled infrared detectors, the uncooled infrared focal plane array（IR FPA）, which is the core component of uncooled infrared detectors, is constantly developing towards larger arrays and smaller pixels. Aiming at the diode-type IR FPA, this paper theoretically analyzes the influence of the sensitive element diode on the readout circuit and device performance. While determining the best operating current of the diode, the number of series connected in the diode structure and junction area are the leading performance factors. Based on this conclusion, a p + n-pn-n + p 3-in-1 diode was designed and combined with traditional diodes, “well”-shape diodes, p + n-n + p 2-in-1 diodes,and two 3-in-1 diodes obtained by the direct expansion of p + n-n + p 2-in-1 diodes, which were compared and investigated. The study found that the p + n-pn-n + p 3-in-1 diodes of the six structures had the most significant number of diodes in series under the same size, and the relative junction area was the largest. Using Sentaurus TCAD simulation, it was verified that under the same overall size, the voltage temperature sensitivity（TCV）value of the p + n-pn-n + p 3-in-1 diodes is approximately that of the p + n-n + p 2-in-1 diode, and two types diode of 3-in-1 obtained by direct expansion on the p + n-n + p 2-in-1 diode was 1.5 times, which is 2.6 times and 3.7times the “well” shape diode and traditional diode, respectively. It is proved that the performance of the p + npn-n + p 3-in-1 diode is the best under small pixels, and the expansion of the N-in-1 diode can further optimize the device performance.

Thermopile sensors have a wide range of applications in consumer and industry. Thermopile is the key component of thermopile sensors, and thermal conductivity is a basic thermal parameter of thermopile. Extracting the thermal conductivity of thermoelectric materials in thermopile sensors is of great importance. In this work, wafer acceptable test structures that fabricated along with thermopile sensors are presented. They could guarantee the measured materials are identical to those used in thermopile sensors. The test results are consistent with the reported values, and the validity of structures is verified. This method has the advantages of on-line extraction over a wide temperature range, and simultaneous extraction of thermal conductivity of connecting wire.

Thermopile infrared (IR) sensors are thermal-type sensors. It is of great significance to evaluate its four thermal parameters: Seebeck coefficient, thermal conductance, heat capacitance, and thermal time constant. In this work, an effective self-test method to measure these thermal parameters is proposed that takes advantages of thermopile IR sensors' structural and electrical characteristics and does not need to add heater in structure. The technique to accurately extract thermal parameters is analyzed carefully, and its validity is verified by a thermopile IR sensor. The experimental Seebeck coefficient is consistent with the tested value of on-chip test structure in the same die, and the experimental thermal conductance, heat capacitance, and thermal time constant results agree well with the theoretical analysis of structure. These demonstrate that this method is effective and accurate, as well as simple for researchers to apply.

The multi-sensor fusion test vehicle is proposed to evaluate the mechanical properties in embedded microfluidic cooling. According to the principle of silicon piezoresistive effect, thermal/stress test chip (TSTC) and TSV pressure sensors are fabricated. It is successfully demonstrated the implanted pressure sensors improves the accuracy of pressure data. In addition, the thermal stress caused by local hotspot and the mechanical stress caused by coolant impact together lead to uneven stress distribution on the chip surface. The application of silicon piezoresistive units in embedded microfluidic structure can be used as an important methods for cooling performance and reliability analysis evaluation.

Thermopile sensors have a wide range of applications in consumer and industry. Seebeck coefficient is a basic thermal parameter of thermopile sensors. Extracting the Seebeck coefficient of both materials and thermocouple in thermopile sensors is of great importance. In this work, an on-chip test structure is designed. It consists of a substrate, a framework, supporting legs and a sensitive region which has a resistor serving as both heater and temperature detector. A set of on-chip test structures are fabricated along with a thermopile sensor. Its measurement results are analyzed and compared with apparatus measurement results. These results are consistent with each other, and the validity of structure is verified.

Uncooled infrared (IR) detectors are widely used in industry and civil imaging fields. Moreover, thermal parameters have a strong impact on detectors’ performance, especially under the trend toward higher spatial resolution. Therefore, evaluating them is important for detectors improvement. In this work, inspired by the traditional optical frequency-domain concept, a self-test method for evaluating thermal parameters of an uncooled IR focal plane array (FPA) is proposed. Utilizing a frequency-adjustable pulsed Joule heating power stimulus, the relationship between the Joule heating power, pixels’ thermal parameters, and pixels’ response voltage was first analyzed and established. This method was validated experimentally using a $3\times $ 3 format diode-based detector. For comparison, an experiment applying the steady-state method was also conducted. The results of all experiments were in good mutual agreement, demonstrating the reliability of the proposed method. For a 1280 $\times1024$ format FPA, the steady-state method needs approximately 90 h to finish measurements, while the proposed method requires only 5 min, illustrating that the proposed self-test method could considerably reduce the thermal parameter testing time for large-scale uncooled IR FPA.

Uncooled infrared (IR) detectors have a wide range of applications in consumer and industry. They realize the conversion from IR radiation to thermal heat through an absorber. Absorptivity is the main evaluation parameter of this radiation conversion efficiency. Measuring the absorptivity is of great importance in evaluating detectors’ performance. In this work, according to Kirchhoff’s law of thermal radiation, the absorptivity in a whole IR spectral range is extracted from relation of thermal conductance to absorber temperature only utilizing Joule effect of detectors. The absorptivity in a certain IR spectral range is obtained with the established relationship of absorptivity between different IR spectral ranges. The experiment applying this method is carried out using a thermopile detector integrated with a N-polysilicon heater. And for verification and comparison, the measurement with blackbody optical system and the theoretical calculation are also performed. All results are consistent well with each other, which verifies the validity of the proposed method. This method has the advantage of no sample preparation requirement and is an in-situ self-test measurement. [2021-0185]

MEMS device degradation due to aging and other factors is becoming a major concern because it will cause parametric deviations and catastrophic failures in the mechanical and structural subsystems. However, MEMS testing in general which needs specific sophisticated testing equipment is complicated and time-consuming. To solve these problems, this paper specifically introduces a built-in self-test method which based on the periodic observation of the temperature-dependent output signal. A packaging scheme is designed and the test circuit is built to conduct test experiments on MEMS pressure sensors with different ranges and materials. The experimental results show that this method can effectively test the performance and will not affect the continued normal operation of the sensor. Furthermore, some compensation is made to correct the output to greatly improve the accuracy and reliability. Low cost, ease of implementation, and possibility to monitor in real time are the main advantages.

In this article, we present the design, fabrication, and characterization of a thermopile infrared sensor array (TISA) pixel. This TISA pixel is composed of a dual-layer p+/n- poly-Si thermopile with a closed membrane and an n-channel metal oxide semiconductor (NMOS) switch. To address the challenges in fabrication through the 3D integration method, the anode of the thermopile is connected to the drain of the NMOS, both of which are fabricated on the same bulk wafer using a CMOS compatible monolithic integration process. During a single process sequence, deposition, etching, lithography, and ion implantation steps are appropriately combined to fabricate the thermopile and the NMOS simultaneously. At the same time as ensuring high thermoelectric characteristics of the dual-layer p+/n- poly-Si thermopile, the basic switching functions of NMOS are achieved. Compared with a separate thermopile, the experimental results show that the thermopile integrated with the NMOS maintains a quick response, high sensitivity and high reliability. In addition, the NMOS employed as a switch can effectively and quickly control the readout of the thermopile sensing signal through the voltage, both on and off, at the gate of NMOS. Thus, such a TISA pixel fabricated by the monolithic CMOS-compatible integration approach is low-cost and high-performance, and can be applied in arrays for high-volume production.

Traditional humidity sensors for respiration monitoring applications have faced technical challenges, including low sensitivity, long recovery times, high parasitic capacitance and uncalibrated temperature drift. To overcome these problems, we present a triple-layer humidity sensor that comprises a nanoforest-based sensing capacitor, a thermistor, a microheater and a reference capacitor. When compared with traditional polyimide-based humidity sensors, this novel device has a sensitivity that is improved significantly by 8 times within a relative humidity range of 40-90%. Additionally, the integration of the microheater into the sensor can help to reduce its recovery time to 5 s. The use of the reference capacitor helps to eliminate parasitic capacitance, and the thermistor helps the sensor obtain a higher accuracy. These unique design aspects cause the sensor to have an excellent humidity sensing performance in respiration monitoring applications. Furthermore, through the adoption of machine learning algorithms, the sensor can distinguish different respiration states with an accuracy of 94%. Therefore, this humidity sensor design is expected to be used widely in both consumer electronics and intelligent medical instrument applications.

With the development of high-performance multi-core microprocessors, the increase in hotspots density poses a severe challenge to chip thermal management. Embedded cooling can improve the cooling performance at the chip level. However, the cooling efficiency will be deteriorated by the interaction of hotspots. This paper proposes the concept of thermal superposition effect based on the relationship between the cooling efficiency of two hotspots and their relative positions. The effective cooling area and superposition area describe the thermal characteristics and interaction of hotspots, and the superposition factor beta evaluates the intensity of interaction. By optimizing the superposition factor, the average temperature reduces 22%. Moreover, the factor can predict the average temperature of hotspots within the error under14%. Therefore, the thermal superposition effect and factor beta is an effective analysis tool in multi-hotspot cooling, simplifying the analysis process and making it possible to predict and optimize the interaction by experiment and finite element simulation.

The response time is an important parameter for thermopiles sensors, which reflects the response speed of the device. The accurate measurement of response time is extremely important to evaluate device characteristics for using them in suitable scenarios. In this work, to accurately measure the response time of thermopile sensors, an Al microheater is integrated in a MEMS thermopile as an in situ heat source. Compared with the traditional chopper measurement method for response time, this approach avoids mechanical delay induced by chopper blades. Accordingly, based on this approach, the response time of the device is measured to be 6.9 ms, while that is 12.7 ms when a chopping system is used, demonstrating that an error of at least 5.8 ms is avoided. Such an approach is quite simple to realize and provides a novel route to accurately measure the response time.

Vacuum equipment has a wide range of applications, and vacuum monitoring in such equipment is necessary in order to meet practical applications. Pirani sensors work by using the effect of air density on the heat conduction of the gas to cause temperature changes in sensitive structures, thus detecting the pressure in the surrounding environment and thus vacuum monitoring. In past decades, MEMS Pirani sensors have received considerable attention and practical applications because of their advances in simple structures, long service life, wide measurement range and high sensitivity. This review systematically summarizes and compares different types of MEMS Pirani sensors. The configuration, material, mechanism, and performance of different types of MEMS Pirani sensors are discussed, including the ones based on thermistors, thermocouples, diodes and surface acoustic wave. Further, the development status of novel Pirani sensors based on functional materials such as nanoporous materials, carbon nanotubes and graphene are investigated, and the possible future development directions for MEMS Pirani sensors are discussed. This review is with the purpose to focus on a generalized knowledge of MEMS Pirani sensors, thus inspiring the investigations on their practical applications.

The networked thermopile array in row-column fashion suffered from the crosstalk caused by parasitic parallel paths. To measure accurate two-dimensional thermal information, it is of great importance to eliminate the crosstalk. In this work, based on the response voltage non-linearity of thermopile pixels as well as the response voltage non-uniformity of array, a projection transformation method that suits for small-scale networked thermopile arrays is proposed. It transforms the crosstalk elimination problem into an overdetermined non-linear least squares problem, and is solved by the Newton-Raphson iterative algorithm. Its reconstruction error is analyzed carefully by Monte Carlo simulation, and its ability to implement non-uniformity and defective pixel correction is also discussed. Its validity is verified experimentally using a $3 \times 3$ networked thermopile array. The experimental result shows that the original IR image can be reconstructed from measured IR images by this method, and the reconstruction error is significantly decreased from 17.03% to 2.10%.