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Flexible perovskite solar cells (PSCs) such as inverted PSCs are gaining increasing attention due to their wide range of potential applications, while the selection of stable, high conductivity and energy level suitable hole transport layers (HTLs) is still challenging. Here we introduce dopant-free copper phthalocyanine (CuPc) as HTL in inverted planar PSCs, and demonstrate improved photovoltaic performance and increased stability with high reproducibility and uniformity compared to the PEDOT:PSS based devices. The champion efficiency of PSCs is achieved by 15.4% on rigid substrates and 12.8% on flexible substrates, respectively. The flexible devices also exhibit excellent bending stability, retaining ∼85% of the original power conversion efficiency (PCE) after 3000 bending cycles at r = 5 mm without encapsulation. Our study provides a new strategy for fabricating cost-effective, scalable and flexible PSCs with high efficiency, little hysteresis, and excellent stability. [ABSTRACT FROM AUTHOR]

• A near-infrared fiber-optic spectrometer system for in-situ online cutting temperature measurement is proposed. • Spectral analysis method and artificial neural network are introduced for spectral-temperature mapping. • Online measurement of cutting temperatures in dry/wet cuttings of constant and varied regimes are realized. • Tool wear status recognition is realized based on cutting temperature by sparse autoencoder and k -means clustering. • The capability of the system in heavy-duty cutting is proved. The cutting temperature is essential for phenomena understanding and quality improvement in metal cutting while its in-situ online measurement is still a challenge. This paper presents a near-infrared fiber-optic multi-spectral method for in-situ online cutting temperature measurement. Using thermal radiation spectrum for temperature measurement, the method optimizes the lower limit of temperature measurement to 150 °C while improving accuracy. The calibration shows that in the range of above 250 °C, the average relative error of temperature measurement is stable below 0.5%. The titanium alloy cutting experiments are carried out. In-situ online measurement of tool temperatures in dry/wet cuttings are realized using the self-developed system. The influence of cutting parameters on cutting temperature is studied, and the real-time response of the temperature measurement system to the cutting state is verified. As for industrial application, the capability of the system in heavy-duty turning is proved by railway wheelsets turning experiments. Tool wear experiments are conducted, and a positive correlation between the cutting temperature and tool wear is revealed. Tool wear status recognition is realized based on cutting temperature by sparse autoencoder and k -means clustering, and a recognition accuracy of 97.3% is achieved. These results indicate promising prospects in cutting mechanism research, machining status monitoring and industrial applications, empowering the advancement of intelligent manufacturing and industry 4.0. [ABSTRACT FROM AUTHOR]

• A near-infrared fiber-optic two-color pyrometer system to monitor the cutting edge temperature. • Good stability and fast dynamic responses are validated by continuous and interrupted cutting experiments. • The ability of sensing cutting regime changes during machining is validated. • The relationship between the cutting temperature change and tool wear is discussed. • Tool damage warning potential before the tool breakage is confirmed. Cutting temperature in machining process has received extensive attention due to its significant influence on tool life and workpiece quality. Research on real-time monitoring of the cutting temperature still faces many challenges, including rapidly changing temperature, high temperature gradient, limited installation space, and flowing chips and coolant. In this paper, a near-infrared fiber-optic two-color pyrometer system is proposed to obtain real-time temperature of the cutting edge during turning. A sensor probe is inserted into a micro-hole of the tool near the cutting edge. The infrared rays radiated from the hole is received by the sensor probe, led by the optical fiber to a plano-convex lens, and split into two identical rays by a beam splitter. Then the two rays passing through specific band filters are focused by two plano-convex lenses on two amplified photodetectors, and the electrical signals are acquired by a data acquisition card. Typical difficult-to-cut material is selected as workpiece in turning. The pyrometer system shows good stability and dynamic response in continuous cutting and interrupted cutting experiments, respectively. The measured cutting temperature is responsive to the changed cutting regime, increasing with the increase of the cutting speed, cutting depth and feed rate in continuous cutting. Repeated cutting experiments are performed for further validation. It is found that the rapid wear in the tool flank face is accompanied by an obvious increase in the cutting temperature, and the cutting temperature rises sharply before the tool breakage. These results indicate the potential of the pyrometer for real-time monitoring of the working tool and early warning of the tool damage. [ABSTRACT FROM AUTHOR]

In this study. a novel near-infrared fluorescent-driven contrast agent (Ag-doped NaYF4:Yb3+/Er3+@NaYF4:Nd3+@NaGdF4) was synthesized using a coprecipitation-hydrothermal-solvothermal-solvothermal (CHSS) method. The results shows that hexagonal NaYF4:Yb3+/Er3+ with a diameter of 300 nm was successfully synthesized by the CHSS method. The new contrast agent was characterized using scanning electron microscopy, fluorescence spectrometry, transmission electron microscopy, energy-dispersive spectrometry and ultraviolet-visible light diffuse reflectance absorption spectroscopy. Even at low concentrations (0.2 M), this proposed contrast agent can be excited by near-infrared light with a wavelength of 980 nm and emits a dazzling green light with a wavelength of 540 nm, and the comparison of the luminescence intensity proves that doping with silver increases the luminescence intensity of the upconverted nanomaterial by nearly 13 times based on the calculated quantum yield. TEM images show the successful preparation of silver nanoparticles with a diameter of 30 nm, and the energy spectrum shows the successful doping of silver nanoparticles and the successful preparation of the core-shell structure of NaYF4:Yb3+/Er3+@NaYF4:Nd3+@NaGdF4. Furthermore, the mechanism of the increased luminous intensity has been studied using simulation calculations. Finally, cytotoxicity tests were used to test material which was modified by 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[amino(polyethylene glycol)-2000] (DSPE-PEG2K), and the biocompatibility was significantly improved, meeting the standard for biological applications. [ABSTRACT FROM AUTHOR]

Two key concerns exist in contemporary cancer chemotherapy: limited therapeutic efficiency and substantial side effects in patients. In recent years, researchers have been investigating the revolutionary cancer treatment techniques of photodynamic therapy (PDT) and photothermal therapy (PTT) proposed by many scholars. A photothermal treatment of cancer was synthesized using the hydrothermal method which has high photothermal conversion efficiency and can generate reactive oxygen species (ROS) in cells. Photothermal treatment of tumors has a good short-term effect and photodynamic therapy lasts longer. However, both PTT and PDT have their inevitable shortcomings and it is difficult to completely eradicate a tumor using a single mode of treatment. PTT and PDT synergistic treatment not only inherits the advantages of low toxicity and side effects of phototherapy but also enables the two treatment methods to complement each other. It is an effective strategy to improve curative effects and reduce toxic and side effects. Furthermore, gold doped UCNPs have an exceptionally high target recognition for tumor cells. The gold doped UCNPs, in particular, are non-toxic to normal tissues, endowing the as-prepared medications with outstanding therapeutic efficacy and exceptionally low side effects. These findings may encourage the creation of fresh, effective imaging-guided approaches to meet the goal of photothermal cancer therapy. [ABSTRACT FROM AUTHOR]

In this paper, fast trap behaviors in Ge pMOSFETs with Al2O3/GeOx/Ge gate-stack are evaluated and quantitatively characterized using a novel sub-1-ns ultrafast measurement (UFM) system. By changing the operation temperature and the rising time of the applied gate voltage (${V}_{\text {g}}$), it is found that the fast trap filling process could be observed within the first 10 ns after the gate voltage was applied, and the process would be more clearly characterized at a raised operation temperature. In addition, the trap density distribution and the time constant of the fast traps inside the valence band edge are experimentally extracted based on the UFMs. It is found that the trap densities inside the valence band edge are within the range of 1013 to 1014 cm $^{-2}\cdot \text {eV}^{-1}$ , which are consistent with the reported values from the Hall measurements. It is experimentally confirmed that the time constants of the fast traps in Ge pMOSFETs with Al2O3/GeOx/Ge gate-stack are about 10 ns, and deeper energy level corresponds to smaller time constant. [ABSTRACT FROM AUTHOR]

Metal halide perovskite solar cells (PSCs) have attracted extensive research interest for next-generation solution-processed photovoltaic devices because of their high solar-to-electric power conversion efficiency (PCE) and low fabrication cost. Although the world's best PSC successfully achieves a considerable PCE of over 20% within a very limited timeframe after intensive efforts, the stability, high cost, and up-scaling of PSCs still remain issues. Recently, inorganic perovskite material, CsPbBr, is emerging as a promising photo-sensitizer with excellent durability and thermal stability, but the efficiency is still embarrassing. In this work, we intend to address these issues by exploiting CsPbBr as light absorber, accompanied by using Cu-phthalocyanine (CuPc) as hole transport material (HTM) and carbon as counter electrode. The optimal device acquires a decent PCE of 6.21%, over 60% higher than those of the HTM-free devices. The systematic characterization and analysis reveal a more effective charge transfer process and a suppressed charge recombination in PSCs after introducing CuPc as hole transfer layer. More importantly, our devices exhibit an outstanding durability and a promising thermal stability, making it rather meaningful in future fabrication and application of PSCs. [ABSTRACT FROM AUTHOR]

In this paper, a novel method is proposed for the extraction of the transistor electrical parameters at the nanosecond timescale. This technique is enabled by an ultra-fast measurement (UFM) system that mainly contains the arbitrary waveform generator and a high-speed real-time oscilloscope. De-noising, synchronization and calibration problems are solved to improve the accuracy and precision. To circumvent the circuit problem at the drain of the transistors, a three-dimensional (3-D) I-V characterization solution is reported, and the I D - V G and I D - V D measured at sub-1 ns time are then drawn. The I-V curves measured in 800 ps show unprecedented agreement with that measured by a standard parameter analyzer and can be used for device/circuit modeling and reliability behaviors studies. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the carrier transport characteristics of the ultrascaled Si FinFETs. Traditional dc characterization technique is compared with the ultrafast pulsed IV method. Due to the severe self-heating effect introduced in the characterization process, the ballistic transport parameters extracted using dc method would show essential discrepancies from those in the real high-speed IC circuits. Therefore, an ultrafast pulsed IV measurement technique is proposed for accurate ballistic transport characterization. Furthermore, since the series resistance ( R{\textbf {SD}} ) of the Si FinFETs is temperature-dependent, a modified backscattering model is adopted to extract the ballistic transport parameters without the influence of the temperature-variant R{\textbf {SD}} . A ballisticity scaling model was established to predict the scalability of the ballistic transport parameters. It is found that very high ballisticity could be achieved for FinFETs with sub-10-nm technology nodes. [ABSTRACT FROM AUTHOR]

In this study. a novel near-infrared fluorescent-driven contrast agent (Ag-doped NaYF4:Yb3+/Er3+@NaYF4:Nd3+@NaGdF4) was synthesized using a coprecipitation-hydrothermal-solvothermal-solvothermal (CHSS) method. The results shows that hexagonal NaYF4:Yb3+/Er3+ with a diameter of 300 nm was successfully synthesized by the CHSS method. The new contrast agent was characterized using scanning electron microscopy, fluorescence spectrometry, transmission electron microscopy, energy-dispersive spectrometry and ultraviolet-visible light diffuse reflectance absorption spectroscopy. Even at low concentrations (0.2 M), this proposed contrast agent can be excited by near-infrared light with a wavelength of 980 nm and emits a dazzling green light with a wavelength of 540 nm, and the comparison of the luminescence intensity proves that doping with silver increases the luminescence intensity of the upconverted nanomaterial by nearly 13 times based on the calculated quantum yield. TEM images show the successful preparation of silver nanoparticles with a diameter of 30 nm, and the energy spectrum shows the successful doping of silver nanoparticles and the successful preparation of the core-shell structure of NaYF4:Yb3+/Er3+@NaYF4:Nd3+@NaGdF4. Furthermore, the mechanism of the increased luminous intensity has been studied using simulation calculations. Finally, cytotoxicity tests were used to test material which was modified by 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[amino(polyethylene glycol)-2000] (DSPE-PEG2K), and the biocompatibility was significantly improved, meeting the standard for biological applications. [ABSTRACT FROM AUTHOR]

Due to harsh environment in the cutting area, access to the cutting region is still limited for the existing temperature sensors. As such, measuring temperature signals remains a challenge for real-time tool wear monitoring. In this paper, a polycrystalline cubic boron nitride (PCBN) cutting tool embedded with thin-film thermocouple (TFTC) was devised and used for tool wear monitoring during the cutting of hardened AISI O2 tool steel. A detailed manufacturing process of the smart tool was introduced. Performance tests for the smart insert were evaluated and results showed that the embedded TFTC had a sensitivity of 14.4 μV/℃, good dynamic response, and functional validity. Wear experiments were implemented under two sets of cutting parameters to explore the relationship between cutting temperature and tool wear. The results showed that the increased maximum cutting temperature could well reflect the progression of flank wear. Obvious fluctuation in temperature signal could also well reflect the abnormal condition of the tool. The devised smart tool will be useful for determining optimum cutting parameters and extending tool life. [ABSTRACT FROM AUTHOR]

Measurement of the temperature at the tool-chip interface is still a significant challenge especially for machining difficult-to-machine material like titanium alloys. In this paper, a versatile PCBN tool, starting with the existing tool shape, was devised by embedding thin-film thermocouples (TFTCs) into tool interior to monitor the temperature at the tool-chip interface while machining titanium alloy bar. A simplified process was developed to fabricate TFTC array with a degree of spatial resolution (100 μm). A diffusion bonding technique was realized between PCBN plates to achieve reliable sensor protection with shorter sintering time and lower sintering temperature while metallic interlayer like titanium film was adopted. The sensors exhibit an excellent linear response with a sensitivity of about 13 μV/℃. Dry cutting including interrupted and continuous cutting was implemented with the fabricated PCBN insert. Results show that TFTCs embedded into PCBN insert not only have a good transient perception by comparing with commercial sensors but also can stably monitor cutting temperature as close as 300 μm to tool-chip interface under different cutting conditions. The devised PCBN tool presented in this paper will also be helpful for the improvement of machining processes and better understanding of the tool-chip contact phenomena. [ABSTRACT FROM AUTHOR]