Analyzing the value of technology based on the differences of patent citations between applicants and examiners

Patent applicants and examiners do not always have the same point of view when conducting a prior-art search. Although several studies have suggested differences between citations by applicants and examiners, the data and range of empirical studies are too incomplete to generalize the characteristics of relationships between citation types and the value of a technology or invention. To overcome this limitation, it is crucial to compare citations by applicants and by examiners in depth, with diverse perspectives and data, to determine the value of patent information for technological innovation. Thus, this paper suggests that the differences in the composition of technical information and patent quality in patent-level investigations as well as the locus of the knowledge source and knowledge recentness in knowledge-level investigations according to patent citation type (by applicants and examiners) reflect Pavitt’s perspective on the nature, impact, and source of technological innovation. We found that the quality of patents cited by applicants is higher than that of those by examiners in four industries, excluding a supplier-dominated industry. The citation types are related to the locus of the knowledge source in four industries, excluding the supplier-dominated industry. In particular, the patents cited by examiners tended to be more recently issued in all sectoral fields. This research contributes to confirming the technological value of patents based on the citation behaviors of applicants and examiners through empirical analysis. The results can be utilized to investigate signals or noise in technological innovation and improve processes or systems of patent examination. In addition, it can help applicants conduct more thorough prior-art searches by comprehending the examiner’s perspective toward citations to increase the probability of patent registration.     

Oxidation behaviour in Si-containing low-carbon steels

Oxygen partial pressure at the boundary between external oxidation layer and steel matrix was determined by characterisation of internal oxidation in Si-containing low-carbon steels oxidised under atmospheric condition. The oxygen partial pressure calculated from the rate equation of the internal oxidation matches with the equilibrium value between Fe and FeO. From the oxygen partial pressure between external oxidation layer and steel matrix, the evolution of internal oxidation zone and the diffusion profile of solute Si were numerically simulated. The calculated depth of internal oxidation and solute Si profile accords to the measured ones from the EPMA, which implies that the numerical simulation captures reasonably the evolution of the internal oxidation in the Si-containing steels.     

Microtopography‐Guided Conductive Patterns of Liquid‐Driven Graphene Nanoplatelet Networks for Stretchable and Skin‐Conformal Sensor Array

Flexible thin‐film sensors have been developed for practical uses in invasive or noninvasive cost‐effective healthcare devices, which requires high sensitivity, stretchability, biocompatibility, skin/organ‐conformity, and often transparency. Graphene nanoplatelets can be spontaneously assembled into transparent and conductive ultrathin coatings on micropatterned surfaces or planar substrates via a convective Marangoni force in a highly controlled manner. Based on this versatile graphene assembled film preparation, a thin, stretchable and skin‐conformal sensor array (144 pixels) is fabricated having microtopography‐guided, graphene‐based, conductive patterns embedded without any complicated processes. The electrically controlled sensor array for mapping spatial distributions (144 pixels) shows high sensitivity (maximum gauge factor ≈1697), skin‐like stretchability (<48%), high cyclic stability or durability (over 10⁵ cycles), and the signal amplification (≈5.25 times) via structure‐assisted intimate‐contacts between the device and rough skin. Furthermore, given the thin‐film programmable architecture and mechanical deformability of the sensor, a human skin‐conformal sensor is demonstrated with a wireless transmitter for expeditious diagnosis of cardiovascular and cardiac illnesses, which is capable of monitoring various amplified pulse‐waveforms and evolved into a mechanical/thermal‐sensitive electric rubber‐balloon and an electronic blood‐vessel. The microtopography‐guided and self‐assembled conductive patterns offer highly promising methodology and tool for next‐generation biomedical devices and various flexible/stretchable (wearable) devices.     

Comparison of regional cerebral blood flow in Parkinson's disease with depression and major depression

Diagnosis of depression in Parkinson's disease (PD) patients is complicated due to the overlapping symptoms of the two disorders. We investigated regional cerebral blood flow (rCBF) in patients with only major depression (MD) and PD patients with (PDMD) and without MD (PDNMD) using ^99mTc hexamethylpropyleneamine oxime single photon emission computed tomography (HMPAO‐SPECT). A total of 103 patients (38 PDMD, 46 PDNMD, and 19 MD patients) underwent brain HMPAO‐SPECT scans. Voxel‐wise whole‐brain analysis was conducted to compare rCBF of the PDMD group with that of the PDNMD and MD groups. The scores of the Geriatric Depression Scale (GDS) and Neuropsychiatric Inventory (NPI) were significantly higher in the PDMD group than in the PDNMD group. The PDMD group showed significant hypoperfusion in the subcallosal cortex than the PDNMD group. The MD group showed significant hypoperfusion in the brainstem and inferomedial frontal region compared with the PDMD group. Our findings suggest that dysfunction of the inferomedial frontal cortex may be involved in the pathogenesis of depression in PD patients.     

Interface Control of Ferroelectricity in an SrRuO3/BaTiO3/SrRuO3 Capacitor and its Critical Thickness

The atomic‐scale synthesis of artificial oxide heterostructures offers new opportunities to create novel states that do not occur in nature. The main challenge related to synthesizing these structures is obtaining atomically sharp interfaces with designed termination sequences. In this study, it is demonstrated that the oxygen pressure during growth plays an important role in controlling the interfacial terminations of SrRuO₃/BaTiO₃/SrRuO₃ (SRO/BTO/SRO) ferroelectric (FE) capacitors. The SRO/BTO/SRO heterostructures are grown by a pulsed laser deposition method. The top SRO/BTO interface, grown at high (around 150 mTorr), usually exhibits a mixture of RuO₂–BaO and SrO–TiO₂ terminations. By reducing , the authors obtain atomically sharp SRO/BTO top interfaces with uniform SrO–TiO₂ termination. Using capacitor devices with symmetric and uniform interfacial termination, it is demonstrated for the first time that the FE critical thickness can reach the theoretical limit of 3.5 unit cells.     

Brain‐Inspired Photonic Neuromorphic Devices using Photodynamic Amorphous Oxide Semiconductors and their Persistent Photoconductivity

The combination of a neuromorphic architecture and photonic computing may open up a new era for computational systems owing to the possibility of attaining high bandwidths and the low‐computation‐power requirements. Here, the demonstration of photonic neuromorphic devices based on amorphous oxide semiconductors (AOSs) that mimic major synaptic functions, such as short‐term memory/long‐term memory, spike‐timing‐dependent plasticity, and neural facilitation, is reported. The synaptic functions are successfully emulated using the inherent persistent photoconductivity (PPC) characteristic of AOSs. Systematic analysis of the dynamics of photogenerated carriers for various AOSs is carried out to understand the fundamental mechanisms underlying the photoinduced carrier‐generation and relaxation behaviors, and to search for a proper channel material for photonic neuromorphic devices. It is found that the activation energy for the neutralization of ionized oxygen vacancies has a significant influence on the photocarrier‐generation and time‐variant recovery behaviors of AOSs, affecting the PPC behavior.     

Atomic-Scale Metal–Insulator Transition in SrRuO3 Ultrathin Films Triggered by Surface Termination Conversion

The metal–insulator transition (MIT) in transition-metal-oxide is fertile ground for exploring intriguing physics and potential device applications. Here, an atomic-scale MIT triggered by surface termination conversion in SrRuO₃ ultrathin films is reported. Uniform and effective termination engineering at the SrRuO₃(001) surface can be realized via a self-limiting water-leaching process. As the surface termination converts from SrO to RuO₂, a highly insulating and nonferromagnetic phase emerges within the topmost SrRuO₃ monolayer. Such a spatially confined MIT is corroborated by systematic characterizations on electrical transport, magnetism, and scanning tunneling spectroscopy. Density functional theory calculations and X-ray linear dichroism further suggest that the surface termination conversion breaks the local octahedral symmetry of the crystal field. The resultant modulation in 4d orbital occupancy stabilizes a nonferromagnetic insulating surface state. This work introduces a new paradigm to stimulate and tune exotic functionalities of oxide heterostructures with atomic precision.     

Sensitive Wearable Temperature Sensor with Seamless Monolithic Integration

Accurate temperature field measurement provides critical information in many scientific problems. Herein, a new paradigm for highly sensitive, flexible, negative temperature coefficient (NTC) thermistor-based artificial skin is reported, with the highest temperature sensing ability reported to date among previously reported NTC thermistors. This artificial skin is achieved through the development of a novel monolithic laser-induced reductive sintering scheme and unique monolithic structures. The unique seamless monolithic structure simultaneously integrates two different components (a metal electrode and metal oxide sensing channel) from the same material at ambient pressure, which cannot be achieved by conventional heterogeneous integration through multiple, complex steps of photolithography or vacuum deposition. In addition to superior performance, electronic skin with high temperature sensitivity can be fabricated on heat-sensitive polymer substrates due to the low-temperature requirements of the process. As a proof of concept, temperature-sensitive artificial skin is tested with conformally attachable physiological temperature sensor arrays in the measurement of the temperatures of exhaled breath for the early detection of pathogenic progression in the respiratory system. The proposed highly sensitive flexible temperature sensor and monolithic selective laser reductive sintering are expected to greatly contribute to the development of essential components in various emerging research fields, including soft robotics and healthcare systems.