bluuebunny/crossref_metadata_2025 huggingface dataset:
Ag NPs decorated on the magnetic rod-like hydroxyapatite/MIL-101(Fe) nanocomposite as an efficient catalyst for the reduction of some nitroaromatic compounds and as an effective antimicrobial agent
Authors: Beiranvand Maryam , Farhadi Saeed , Mohammadi-Gholami Abdelnasser
Published: May 2023

A novel HAP/MIL-101(Fe)/Ag/Fe3O4 magnetic nanocomposite was synthesized and used for the rapid catalytic reduction of nitro compounds and as an antibacterial agent at room temperature.
Selectivity of reaction pathways for green diesel production towards biojet fuel applications
Authors: Rahmawati Zeni , Santoso Liangga , McCue Alan , Azua Jamari Nor Laili , Ninglasari Sri Yayu , Gunawan Triyanda , Fansuri Hamzah
Published: May 2023

Green diesel is the second generation biofuel with the same structure as fossil fuels (alkanes), allowing this biofuel to provide excellent fuel properties over biodiesel such as higher energy content and lower hazardous gas emission.
An efficient and green procedure for transformation of thiols to disulfides and thioamides in AGA8 aqueous micelles
Authors: Jin Hao , Liu Penghao , Wang Yuxiang , Zhang Shuai , Meng Qi , Teng Qiaoqiao
Published: May 2023

A sugar-based surfactant AGA8 was designed and demonstrated to promote the synthesis of disulfides and thioamides in water.
The influence of genetic and acquired factors on the vulnerability to develop depression: a review
Authors: Zhang Xingfang , Qiao Yajun , Wang Mengyuan , Liang Xinxin , Zhang Ming , Li Cen , Cairang Jixian , Wang Jianv , Bi Hongtao , Gao Tingting
Published: May 2023

Depression is one of the most common mental disorders that affects hundreds of millions of people worldwide and has claimed tens of thousands of lives. The causes are divided into two main areas: congenital genetic factors and acquired environmental factors. Congenital factors include genetic mutations and epigenetic events; acquired factors include birth patterns, feeding patterns, dietary patterns, childhood experiences, education and economic levels, isolation due to epidemics, and many other complex factors. According to studies, these factors play important roles in depression. Therefore, here, we analyze and study the factors from two aspects, describe their influence on individual depression, and analyze their underlying mechanisms. The results showed that both innate and acquired factors have significant effects on the occurrence of depressive disorder, and these findings may provide new ideas and methods for the study of depressive disorder, thus facilitating the process of depression prevention and treatment.
Unsupervised detection of contrast enhanced highlight landmarks
Authors: Wu Tao , Fan Wenzhuo , Li Shuxian , Li Qingqing , Zhang Jianlin , Li Meihui
Published: May 2023

In the field of landmark detection based on deep learning, most of the research utilise convolutional neural networks to represent landmarks, and rarely adopt Transformer to represent and encode landmarks. Meanwhile, many works focus on modifying the network structure to improve network performance, and there is little research on the distribution of landmarks. In this article,the authors propose an unsupervised model to extract landmarks of objects in images. First, Transformer structure is combined with the convolutional neural network structure to represent and encode the landmarks; next, positive and negative sample pairs between landmarks are constructed, so that the semantically consistent landmarks on the image are pulled closer in the feature space and the semantically inconsistent landmarks are pushed farther in the feature space; then the authors concentrate their attention on the most active points to distinguish the landmarks of an object from the background; finally, based on the new contrastive loss, the network reconstructs the image by the landmarks of the object that are continuously learnt during training. Experiments show that the proposed model achieves better performance than other unsupervised methods on the CelebA, Annotated Facial Landmarks in the Wild, 300W datasets.
A review of bismuth‐based nanoparticles and their applications in radiosensitising and dose enhancement for cancer radiation therapy
Authors: Shahbazi‐Gahrouei Daryoush , Choghazardi Yazdan , Kazemzadeh Arezoo , Naseri Paria , Shahbazi‐Gahrouei Saghar
Published: May 2023

About 50% of cancer patients receive radiation therapy. Despite the therapeutic benefits of this method, the toxicity of radiation in the normal tissues is unavoidable To improve the quality of radiation therapy, in addition to other methods such as IMRT, IGRT, and high radiation dose, nanoparticles have shown excellent potential when ionising radiation is applied to the target volume. Recently, bismuth‐based nanoparticles (BiNPs) have become particularly popular in radiation therapy due to their high atomic numbers (Z), high X‐ray attenuation coefficient, low toxicity, and low cost. Moreover, it is easy to synthesise in a variety of sizes and shapes. This study aimed to review the effects of the bismuth‐based NP and its combination with other compounds, and their potential synergies in radiotherapy, discussed based on their physical, chemical, and biological interactions. Targeted and non‐targeted bismuth‐based NPs used in radiotherapy as radiosensitizers and dose enhancement effects are described. The results reported in the literature were categorised into various groups. Also, this review has highlighted the importance of bismuth‐based NPs in different forms of cancer treatment to find the highest efficiency for applying them as a suitable candidate for various cancer therapy and future clinical applications.
Complementary waveforms for range sidelobe suppression based on a singular value decomposition approach
Authors: Wang Jiahuan , Fan Pingzhi , McLernon Des , Ding Zhiguo
Published: May 2023

While Doppler resilient complementary waveforms (DRCWs) have previously been considered to suppress range sidelobes within a Doppler interval of interest in radar systems, their ability to provide Doppler resilience can be further improved. A new singular value decomposition (SVD)‐based DRCW construction is proposed, in which both transmit pulse trains (made up of complementary pairs) and receive pulse weights are jointly considered. Besides, using the proposed SVD‐based method, a theoretical bound is derived for the range sidelobes within the Doppler interval of interest. Moreover, based on the SVD solutions, a challenging non‐convex optimization problem is formulated and solved to maximise the signal‐to‐noise ratio (SNR) with the constraint of low range sidelobes. It is shown that, compared with existing DRCWs, the proposed SVD‐based DRCW has better Doppler resilience. Further, the new optimised SVD‐based DRCW has a higher SNR while maintaining the same Doppler resilience.
Retracted Article: Research on coordination and optimization of power generation, loading and integrated storage, flexible condition system and response
Authors: Li Dong , Liu Jiyan , Ju Wenjie , Xu Xiaolong , Song Lei , Song Peixin , Jiang Sichong
Published: May 2023

The authors have expressed the wish to retract this article on the ground that there are some technical issues that require to be corrected. The Publisher and Editor(s) approved to the retraction.
Study on Calibration of Chromlum(VI) Analyzer
Authors: Peng Jianchun , Li Xianhong , Liu Ying , Ren Tingting , Mo Hongbo
Published: May 2023

This article presents a novel metrological calibration method for trace chromium(VI) analyzer. The study identifies all factors that affect the accuracy of chromium(VI) analyzers, and proposes calibration items and method for the analyzer based on its working principle. The calibration items include pump set flow error and pump flow stability, set temperature error and temperature control stability of column oven, baseline noise and drift, minimum detection concentration, linear range, and qualitative and quantitative repeatability. Experimental results shows that, the presented method can meet the requirements for the metrological performance evaluation of chromium(VI) analyzer. The calibration method is scientific and feasible.
A Study on crystallization temperature and rate of ammonium salt in the high-pressure hydrogenation heat exchanger
Authors: Tang Zhixuan , Ye Wenying , Wang Jinguang , Wang Qiang , Zhou Guo-Yan
Published: May 2023

Ammonium salt crystallization corrosion failure is an essential problem in the failure of high-pressure hydrogenation heat exchangers. The crystallization equilibrium curves of NH4Cl and NH4HS under different pressures were established according to the ammonium salt crystallization process in the high-pressure hydrogenation heat exchange unit, and the crystallization equilibrium temperatures of NH4Cl and NH4HS were obtained based on Aspen Plus. In addition, a prediction model for the crystallization temperature of ammonium salt was established, then the relationship between crystallization temperature and rate of ammonium salts was elaborated. The results indicate that the initial crystallization temperatures of NH4Cl and NH4HS are respectively 198.95°c and 134.45°c when the system pressure is 10MPa, and the temperature is 433.15K. The maximum crystallization rate of NH4Cl and NH4HS occur at the initial crystallization temperature, respectively 0.104kg/h and 29.23kg/h. The crystallization rate of NH4HS is three orders of magnitude higher than that of NH4Cl.
Research on SOFC Properties of Low Concentration Gas Fuel and SFM-GDC Reforming
Authors: Han Chao , Dong Xinyue , He Leiyi , Xu Jin , Li Pengxiang , Li Jiakang
Published: May 2023

When gas fuel is used in solid oxide fuel cells, methane cracking occurs at high temperature in the Ni-based anode, forming granular carbon deposition in the active site of the anode, and finally completely wrapped Ni metal, greatly losing the electrochemical performance. Therefore, it is very necessary to add a reforming catalytic layer in the anode of the battery. The methane is reformed into CO and H2 fuel before entering the anode, and the place where methane cracking occurs is mostly transferred to the reforming layer, which reduces the catalytic reforming burden of the Ni-based anode, so as to effectively improve the battery performance. In this paper, Sr2Fe1.5Mo0.5O6 with double perovskite structure was synthesized and prepared, which maintained very good stability in high temperature REDOX atmosphere and had high electrical conductivity. The combination of GDC and SFM can increase the reaction site of the three-phase interface of the reforming layer, and also help to improve the thermal expansion matching between the reforming layer and anode. In this paper, the electrochemical performance of straight cell coated with SSFM-GDC reforming layer has been studied. Low concentration gas in coal mine contains methane, oxygen, nitrogen, and water hydrogen sulfide, etc., and its reaction process in solid oxide fuel cells is complicated. Therefore, studying the reaction mechanism of low concentration gas in solid oxide fuel cells has important practical significance for promoting its application.
A study on the synthesis, modification and current market status of PBAT
Authors: Xu Wenjing
Published: May 2023

With the increasing awareness of environmental protection, the problem of "white pollution" caused by waste plastics has become more and more important to all countries, and the restriction of plastic and plastic ban has become a global consensus, which has ushered in a good opportunity for the biodegradable plastic industry. Polybutylene adipate-butylene terephthalate (PBAT) is one of the most widely used biodegradable plastics at present. This paper mainly introduces the synthesis, modification and current market status of PBAT. At present, the synthesis process of PBAT mainly adopts direct esterification method, often blended with other resins for modification, and the prepared products are used in the field of film bags. In recent years, the production capacity of PBAT has grown significantly, mainly in China.
Study on preparation and properties of zinc ferrite and titanium dioxide
Authors: Yang Jinlin , Huo Xingnan , Li Zongyu , Ma Shaojian
Published: May 2023

In this paper, sulfuric acid leaching high iron zinc calcine was used to prepare and purify zinc ferrite, high temperature roasting method was used to prepare synthetic zinc ferrite, and sol-gel method was used to prepare TiO2. The properties of the prepared samples ware characterized by XRD, FT-IR, BET, SEM and other methods. The results show that the synthetic zinc ferrite is pure zinc ferrite, and the purified zinc ferrite contains impurities PbSO4. The TiO2 crystal form prepares at the calcination temperature of 300~550°C is basically the same, and the crystal form transformation occurs at the calcination temperature of 550~600°C. TiO2 samples calcines at 400°C (T400) have higher specific surface area, larger total pore volume and average pore diameter. The crystalline degree of synthetic zinc ferrite is high, the micropores on the crystal surface are closed, and the grains bond with each other. The specific surface area, total pore volume and average pore diameter of purified zinc ferrite are larger than those of synthetic zinc ferrite. The effects of specific surface area, pore volume and pore structure on the adsorption capacity and catalytic efficiency are as follows: T400> purified zinc ferrite > synthesized zinc ferrite.
Continuous synthesis and transformation of diazomethane
Authors: Dong Mengqi , Teng Dawei , Cao Guorui
Published: May 2023

Diazomethane is the simplest diazo compound with high reactivity and is an exceptionally versatile C1-building block. However, diazomethane’s application is greatly limited due to its special properties such as highly toxic, carcinogenic, inflammable and explosive. The application of the one-pot reaction and emerging continuous flow technology in the field of hazardous chemicals enable the generated diazomethane to be directly consumed and transformed, effectively ensuring the safety of the reaction process and providing the possibility for its mass production and use. According to the different precursors of diazomethane, the applications of diazomethane in continuous synthesis and in situ transformation in laboratory and industry are systematically summarized.
Eine Fallstudie zum kieferorthopädischen
Lückenschluss mittels Alignern unter Berücksichtigung
20-jähriger, klinische Erfahrung und technologischer
Entwicklung
Authors: Drechsler Thomas
Published: May 2023

Im Rahmen der 50. internationalen kieferorthopädischen Fortbildungstagung
der Österreichischen Gesellschaft für Kieferorthopädie
zeigte der Autor in einem Übersichtsreferat anhand klinischer
Behandlungen die Entwicklung der Aligner-Orthodontie auf. Demnach konnte sich
seit über 20 Jahren die kieferorthopädische Therapie mittels
seriell hergestellter Miniplastschienen zunehmend mehr als Ergänzung
oder Substitution zu den klassischen, herausnehmbaren Geräten oder
Multibracket-Apparaturen etablieren.

Wurde der Indikationsbereich in den ersten Jahren noch als sehr
eingeschränkt und ausschließlich für die Behandlung
erwachsender Patienten angesehen, so eignet sich die Anwendung der digitalen
Aligner-Technik mittlerweile auch zur Therapie bei Kindern und Jugendlichen und
ebenso zur Lösung komplexer kieferorthopädischer
Behandlungsaufgaben.

Entscheidend ist hierbei aber die unbedingte Einhaltung der
allgemeingültigen, medizinisch- kieferorthopädischen Standards
von der Diagnostik, der Planung bis einschließlich der
persönlichen Behandlungsführung mit den fundierten
Fachkenntnissen des fortgebildeten Fachzahnarztes für
Kieferorthopädie.

So sind bei Kenntnis der anatomischen Befunde, unter Berücksichtigung der
biomechanischen Grundlagen, der Eignung des Patienten und der entsprechenden
Expertise des Arztes nicht nur ausgeprägtere dentoalveoläre
Fehlstellungen wie Engstände, sondern auch deutliche vertikale und
sagittale Abweichungen mit Alignern grundsätzlich therapierbar.
Herausfordernd bleibt aber insbesondere die Durchführung
körperlicher, translatorischer Zahnbewegungen zum orthodontischen
Lückenschluss, wie es beim Fehlen von Zähnen indiziert sein
kann.

Am Beispiel einer besonderen Lückensituation, die infolge eines Traumas
durch Verlust des mittleren und seitlichen Schneidezahnes bei einen zehn Jahre
alten Jungen entstanden ist, sollen hier die Möglichkeiten und Grenzen
der Aligner- Therapie aufgezeigt werden. Besonderer Beachtung gilt hier der
Zahnbewegung über die obere Mittellinie, die in der Literatur bereits
mehrfach beschrieben wurde, bislang aber noch nicht umfassend in der
Aligner-Orthodontie dargestellt wurde.
Ambulante Long/Post-COVID-Versorgung: Analyse
möglicher Barrieren und Wünsche von Betroffenen an die
ärztliche Betreuung
Authors: Reuken Philipp Alexander , Trommer Sabine , Besteher Bianca , Bleidorn Jutta , Finke Kathrin , Lemhöfer Christina , Stallmach Andreas , Giszas Benjamin
Published: May 2023

Einleitung Persistierende und neu-auftretende Beschwerden nach einer
SARS-CoV-2-Infektion (sog. Long/Post-COVID-Syndrom) stellen eine
große Herausforderung für unser Gesundheitssystem dar. Analysen
zu Bedürfnissen von Betroffenen an die primäre Behandlung und
Versorgungsplanung sind rar, sodass die gezielte Lenkung von
Patientenströmen und letztlich auch die Patientenversorgung deutlich
erschwert ist.

Methoden Die JenUP-Studie (Jenaer Untersuchung zum populations-basierten
Auftreten von Post-COVID-Beschwerden) ist eine fragebogenbasierte Untersuchung
aller Erwachsenen der Stadt Jena, welche zwischen März 2020 und
September 2021 mit einer RT-PCR-bestätigte SARS-CoV-2-Infektion durch
das Gesundheitsamt Jena registriert wurden. Ein Teil dieser Studie
beschäftigt sich mit der ärztlichen Betreuung von Betroffenen
mit prolongierten/persistierenden Symptomen sowie deren subjektiven
Schwierigkeiten im Rahmen dieser Behandlung.

Ergebnisse Insgesamt beantworten 1,008 der 4,209 angeschriebenen Personen
den zugesendeten Fragebogen, wobei 922 (91,5%) über das
Auftreten von mindestens einem Long/Post-COVID-assoziierten Symptom
berichteten. 85,6% dieser Personen (790/922) gaben zudem
detaillierte Auskünfte über Kontakte mit Einrichtungen und
Personen des Gesundheitswesens. Drei von vier Personen (590/790)
stellten sich im Zusammenhang mit ihren Beschwerden hausärztlich vor,
155/790 (19,6%) konsultierten, meist zusätzlich,
Fachspezialist:innen (am häufigsten Internist:innen –
7,1% (55/790). Schwierigkeiten eine subjektiv benötigte
Therapie zu erhalten, wurden von 22,6% (162/718) der Befragten
angegeben. Als Gründe wurden vornehmlich das patientenseitige
Gefühl scheinbar „nicht krank genug zu sein“
(69/162) und ein fehlender Ansprechpartner (65/162)
angeführt. 27% (247/919) aller Probanden mit
Long/Post-COVID-Beschwerden äußerten den Wunsch nach
einem konkreten Ansprechpartner.

Schlussfolgerung Die hausärztliche Betreuung stellt eine zentrale
Säule der ambulanten Versorgung von Long/Post-COVID-Patienten
dar. Zudem sollten gemäß der nationalen S1-Leitlinie
flächendeckende Strukturen zur interdisziplinären Betreuung
aufgebaut werden. Die Analyse wahrgenommener Barrieren bei der
ärztlichen Betreuung und der Wünsche für die Versorgung
stellen einen ersten Schritt zur Verbesserung der ambulanten Versorgung von
Long/Post-COVID-Patienten dar.
Transverse Cervical Artery for Head and Neck Reconstruction with Free Jejunal Flaps: A Retrospective Study of Computed Tomography Angiography
Authors: Fujisawa Kou , Miyamoto Shimpei , Saito Yuki , Suzuki Sho , Okazaki Mutsumi
Published: May 2023

Background The transverse cervical artery is less commonly used than other external carotid arteries as a recipient vessel. Therefore, we aimed to compare the utility of the transverse cervical artery as a recipient vessel with that of the external carotid artery system for microvascular head and neck reconstruction by quantitative analysis of dynamic-enhanced computed tomography.

Methods Fifty-one consecutive patients who underwent free jejunum transfer following total pharyngolaryngectomy between January 2017 and December 2020 were retrospectively reviewed. Ninety-four pairs of the diameters of the transverse cervical artery, superior thyroid artery, and lingual artery, measured via computed tomography angiography, were analyzed. Operative outcomes were compared between the following groups based on the recipient artery: transverse cervical artery (n = 27), superior thyroid artery (n = 17), and other artery (n = 7) groups.

Results In the analysis of the computed tomography angiography, nine transverse cervical arteries (9.6%) could not be identified. However, the percentage was significantly lower than the percentage of superior thyroid arteries (20.2%) and lingual arteries (18.1%) (p < 0.01). Among the identified vessels, the transverse cervical arteries (2.09 ± 0.41 mm) and the lingual arteries (1.97 ± 0.40 mm) were significantly larger than the superior thyroid arteries (1.70 ± 0.36 mm) in diameter at the commonly used level (p < 0.01). Multivariate analysis revealed that prior radiation therapy was not an independent factor significantly affecting transverse cervical artery diameter (p = 0.17). Intraoperative anastomotic revision was required in only two cases of the superior thyroid artery.

Conclusion The transverse cervical artery can offer a larger caliber and more reliable candidate than the superior thyroid artery for a recipient artery. More liberal use of the transverse cervical artery may improve the safety of microsurgical head and neck reconstruction.
Primary Targeted Muscle Reinnervation in Above-Knee Amputations in Patients with Unsalvageable Limbs from Limb-Threatening Ischemia or Infection
Authors: Chang Brian L. , Hill Alison L. , Mondshine Joshua , Harbour Patrick W. , Episalla Nicole C. , Attinger Christopher E. , Kleiber Grant M.
Published: May 2023

Background Amputees frequently suffer from chronic pain in both their residual limbs (RLP) and phantom limbs (PLP) following their amputation. Targeted muscle reinnervation (TMR) is a nerve transfer technique that has been demonstrated to improve pain secondarily and at time of amputation. The goal of this study is to report on the efficacy of primary TMR at time of above-knee level amputations in the setting of limb-threatening ischemia or infection.

Methods This is a retrospective review of a single-surgeon experience with TMR in patients undergoing through- or above-knee level amputations from January 2018 to June 2021. Patient charts were reviewed for the comorbidities in the Charlson Comorbidity Index. Postoperative notes were assayed for presence and absence of RLP and PLP, overall pain severity, chronic narcotic use, ambulatory status, and complications. A control group of patients undergoing lower limb amputation who did not receive TMR from January 2014 to December 2017 was used for comparison.

Results Forty-one patients with through- or above-knee level amputations and primary TMR were included in this study. The tibial and common peroneal nerves were transferred in all cases to motor branches to the gastrocnemius, semimembranosus, semitendinosus, and biceps femoris. Fifty-eight patients with through- or above-knee level amputations without TMR were included for comparison. The TMR group had significantly less overall pain (41.5 vs. 67.2%, p = 0.01), RLP (26.8 vs. 44.8%, p = 0.04), and PLP (19.5 vs. 43.1%, p = 0.02). There were no significant differences in complication rates.

Conclusion TMR can safely and effectively be performed at time of a through- and above-knee level amputation and improves pain outcomes.
Synthetic Studies Toward Daphnezomines A and B
Authors: Yang Ming , Dou Chenguang
Published: May 2023

Synthetic studies toward daphnezomines A and B, members of Daphniphyllum alkaloid group with a rare azaadamantane core structure, are reported. The tricyclic carbon skeleton with two contiguous quaternary carbon centers was synthesized in nine steps from (R)-piperitone. An intramolecular Tsuji–Trost reaction was used as a key reaction for the assembly of the skeleton.
Management of Gout with Individualised Homoeopathy: A Case Report
Authors: Jagadabhi Santosh Kumar , Deshpande Vishal
Published: May 2023

Gout is a metabolic disorder in which deposition of monosodium urate crystals leading to inflammatory joint disease. The metabolic derangement leading to supersaturation of blood and body fluids with the urate ion to the point of crystal formation is responsible for the presentation. Gout with acute arthritis or chronic arthritis is treated with non-steroidal anti-inflammatory drugs, colchicine, corticosteroids and drugs that lower levels of uric acid in the blood, but these drugs have their impact on different organs of the body. Homoeopathic system of medicine can treat gouty arthritis effectively without any other sequelae. A case of gout in a 52-year-old male patient who presented with severe pain, swelling and tenderness was successfully treated with homoeopathy medicine, Natrum sulph. The medicine prescribed in totality alleviated not only the symptoms of the patient but also lowered the serum uric acid levels to normal.
Pedagogical competencies in minor subjects of Ghanaian pre-service geography teachers and their implications for teacher education
Authors: Mensah Bismark
Published: May 2023

Despite the proliferation of research on teacher education, pre-service teachers’ pedagogical preparedness to teach their minor subjects has received little attention in the literature. Therefore, this study assessed Ghanaian pre-service geography teachers’ pedagogical competence in their minor subjects, including political science, economics, social studies, and history. Pedagogical competence was conceptualised using three constructs adapted from the Technological Pedagogical Content Knowledge (TPACK) framework: pedagogical knowledge, pedagogical content knowledge, and technological pedagogical knowledge. Through a survey, a total of 182 pre-service geography teachers participated in the study. The empirical data obtained were analysed using descriptive statistics such as mean and standard deviation. A one-way MANOVA test was conducted to explore the differences in the pre-service teachers’ pedagogical competencies based on minor subject classifications. The results showed that the pre-service geography teachers had relatively higher pedagogical knowledge in their minor subject than pedagogical content and technological pedagogical knowledge. Minor subject classifications significantly affected pedagogical knowledge, with higher scores reported among the economics minor group. The implications of the findings for teacher education curricula, in addition to the need for pre-service teachers to read pedagogy-related courses in their minor subjects, are discussed.
Advancing prospects in ultrawide bandgap semiconductor materials
Authors: Ikenson Ben
Published: May 2023

Synthesis achieves better uniformity and tunability in boron-carbon-nitrogen compounds
Two-photon absorption spectrometers for near infrared
Authors: Reyna-Morales Itzel , Garduño-Mejía Jesús , Rocha-Mendoza Israel , Rosete-Aguilar Martha , Qureshi Naser
Published: May 2023

We present a Silicon-based Charge-Coupled Device (Si-CCD) sensor applied as a cost-effective spectrometer for femtosecond pulse characterization in the Near Infrared region in two different configurations: two-Fourier and Czerny–Turner setups. To test the spectrometer’s performance, a femtosecond Optical Parametric Oscillator with a tuning range between 1100 and 1700 nm and a femtosecond Erbium-Doped Fiber Amplifier at 1582 nm were employed. The nonlinear spectrometer operation is based on the Two-Photon Absorption effect generated in the Si-CCD sensor. The achieved spectrometer resolution was 0.6 ± 0.1 nm with a threshold peak intensity of 2×106Wcm2. An analysis of the nonlinear response as a function of the wavelength, the response saturation, and the criteria to prevent it are also presented.
Ab initio study of Raman modes and thermodynamic properties of TinO2n−1
Authors: Hosseini S. Vahid , Abbasnejad Mohaddeseh , Mohammadizadeh Mohammad Reza
Published: May 2023

Titanium suboxides with formula TinO2n−1 have attracted increasing attention owing to their widespread potential applications. Generally, the experimental samples of TinO2n−1 are a mixture of TiO2 suboxides, and the characterization of these phases is not solely possible using x-ray diffraction (XRD). In these cases, Raman modes with XRD can characterize these phases within the samples more precisely. Therefore, the investigation of Raman modes is important. On the other hand, the experimental thermodynamic study predicts that TinO2n−1 can be fabricated with a high index n, where n can take up to 100. So, the Raman modes and thermodynamic properties of these phases, nominally Ti2O3, Ti3O5, and Ti4O7, were investigated within the framework of density functional theory. Comparing the calculated and experimental Raman modes reveals that it is essential to consider the dipole–dipole interaction to reproduce the high Raman modes. Moreover, this electrostatic interaction can be responsible for stabilizing Ti3O5 polymorphs. According to the results, the bipolaronic bonds in Ti3O5 and Ti4O7 lead to a large Born effective charge, which makes these materials plausible for piezoelectric applications. Additionally, thermodynamic calculations reveal that as the n index in TinO2n−1 compounds increases, more stability is achieved at high temperatures, following the experiment. The stability in high temperatures suggests that TinO2n−1 phases can be suitable candidates for thermoelectric devices.
Optical and structural properties of InGaN/GaN quantum well green laser diodes with AlGaN interlayer
Authors: Li Xuan , Liu Jianping , Tian Aiqin , Hu Lei , Ren Xiaoyu , Huang Siyi , Zhou Wei , Wang Dan , Li Deyao , Yang Hui
Published: May 2023

Scanning transmission electron microscope and temperature-dependent photoluminescence were used to study the effects of AlGaN interlayer (IL) following InGaN quantum wells (QWs) on the structural and optical properties of InGaN green laser diodes (LDs) grown on c-plane GaN substrate. It is found that AlGaN IL improves InGaN QW interface sharpness, whereas it does not suppress the localization effect, and moreover, it leads to increasing nonradiative recombination centers in the active region of green InGaN LD. We believe AlGaN IL has advantages and disadvantages to green InGaN LD structures. The advantage is to suppress indium (In) surface segregation, but the disadvantage is that it covers In-rich clusters, which evolve into dark spots during the growth of p-type layers of green LD structures.
Physically consistent testing of large-frequency-band magnetic losses of non-oriented electric steel considering dynamic anisotropy
Authors: Shilyashki Georgi , Pfützner Helmut , Bengtsson Claes , Okubo Tomoyuki
Published: May 2023

Non-oriented (NO) magnetic steels show gradually increasing relevance over an extended range of frequencies, in particular for electric drives. However, until now, data for corresponding characteristics like losses P are available in very restricted ways. A reason is that loss testers are standardized for technical low frequency (LF) until now. Here we report detailed loss data for three steel types, tested by broad-band single sheet testers that offer tests up to high frequency (HF), for values of f = 10 kHz, for steel samples of 500 × 170 mm2 (or 500 mm). In solving a specific problem of NO steel, very high values of H of magnetic field strength are considered by “True Field Air Flux Compensation.” For rising f, the three steels show strong, non-linear increases in losses P, up to about 100 W/kg. With respect to anisotropy, corresponding factors were defined for rolling direction and transverse direction (TD). The effective “field anisotropy” AH tends to show high values for LF but sinks dramatically for HF due to strong eddy currents. The analogously defined “loss anisotropy” AP is lower a priori. In addition, decreases in HF are less pronounced. The International Electrotechnical Commission-standardized “loss anisotropy factor” is generally lower by more than a factor of two, with values up to 30% for LF that may sink to zero for HF due to eddy current mechanisms that are rather independent from crystalline texture. In conclusion, for high dynamics, the effective anisotropy deviates completely from LF-based texture characteristics. Additional analyses of power functions prove that during a period of magnetization, strong anisotropy exists with respect to alignments of atomic moments, in particular for the TD.
Metastable and field-induced ferroelectric response in antiferroelectric lead zirconate thin film studied by the hyperbolic law and third harmonic response
Authors: Nadaud Kevin , Borderon Caroline , Renoud Raphaël , Bah Micka , Ginestar Stephane , Gundel Hartmut W.
Published: May 2023

In this paper, the field-induced residual ferroelectricity in antiferroelectric lead zirconate thin films has been studied by impedance measurements together with a hyperbolic law analysis, which permits us to extract the different contributions to the material’s complex permittivity. By measuring the Rayleigh coefficient αr, it appears that the residual ferroelectricity is considerably enhanced when the sample has been previously exposed to an electric field close to the antiferroelectric to ferroelectric transition field. This indicates that a part of the material remains ferroelectric after the antiferroelectric–ferroelectric backward transition, which constitutes an additional contribution to polarization. Consequently, a higher domain wall density and mobility can be observed. Measurements after exposition to thermal treatment show that this ferroelectric response is metastable.
Perspective: Nanophotonic electro-optics enabling THz bandwidths, exceptional modulation and energy efficiencies, and compact device footprints
Authors: Dalton Larry R. , Leuthold Juerg , Robinson Bruce H. , Haffner Christian , Elder Delwin L. , Johnson Lewis E. , Hammond Scott R. , Heni Wolfgang , Hosessbacher Claudia , Baeuerle Benedikt , De Leo Eva , Koch Ueli , Habegger Patrick , Fedoryshyn Yuriy , Moor David , Ma Ping
Published: May 2023

The growth of integrated photonics has driven the need for efficient, high-bandwidth electrical-to-optical (EO) signal conversion over a broad range of frequencies (MHz–THz), together with efficient, high bandwidth photodetection. Efficient signal conversion is needed for applications including fiber/wireless telecom, data centers, sensing/imaging, metrology/spectroscopy, autonomous vehicle platforms, etc., as well as cryogenic supercomputing/quantum computing. Diverse applications require the ability to function over a wide range of environmental conditions (e.g., temperatures from <4 to >400 K). Active photonic device footprints are being scaled toward nanoscopic dimensions for size compatibility with electronic elements. Nanophotonic devices increase optical and RF field confinement via small feature sizes, increasing field intensities by many orders of magnitude, enabling high-performance Pockels effect materials to be ultimately utilized to their maximum potential (e.g., in-device voltage-length performance ≤0.005 V mm). Organic materials have recently exhibited significant improvements in performance driven by theory-guided design, with realized macroscopic electro-optic activity (r33) exceeding 1000 pm/V at telecom wavelengths. Hybrid organic/semiconductor nanophotonic integration has propelled the development of new organic synthesis, processing, and design methodologies to capture this high performance and has improved understanding of the spatial distribution of the order of poled materials under confinement and the effects of metal/semiconductor-organic interfaces on device performance. Covalent coupling, whether from in situ crosslinking or sequential synthesis, also provides a thermally and photochemically stable alternative to thermoplastic EO polymers. The alternative processing techniques will reduce the attenuation of r33 values observed in silicon organic hybrid and plasmonic organic hybrid devices arising from chromophore-electrode electrostatic interactions and material conductance at poling temperatures. The focus of this perspective is on materials, with an emphasis on the need to consider the interrelationship between hybrid device architectures and materials.
Photon-starved snapshot holography
Authors: Zhang Yunping , Chan Stanley H. , Lam Edmund Y.
Published: May 2023

Digital holography (DH) is a powerful imaging modality that is capable of capturing the object wavefront information, making it very valuable for diverse scientific research applications. Generally, it requires ample illumination to enable good fringe visibility and a sufficient signal-to-noise ratio. As such, in situations such as probing live cells with minimal light interaction and high-speed volumetric tracking in flow cytometry, the holograms generated with a limited photon budget suffer from poor pattern visibility. While it is possible to make use of photon-counting detectors to improve the hologram quality, the long recording procedure coupled with the need for mechanical scanning means that real-time extremely low-light holographic imaging remains a formidable challenge. Here, we develop a snapshot DH that can operate at an ultra-low photon level (less than one photon per pixel). This is achieved by leveraging a quanta image sensor to capture a stack of binary holographic frames and then computationally reconstructing the wavefront through integrating the mathematical imaging model and the data-driven processing, an approach that we termed PSHoloNet. The robustness and versatility of our DH system are demonstrated on both synthetic and experimental holograms with two common DH tasks, namely particle volumetric reconstruction and phase imaging. Our results demonstrate that it is possible to expand DH to the photon-starved regime, and our method will enable more advanced holography applications in various scientific imaging systems.
Thermal conductivity of ScxAl1−xN and YxAl1−xN alloys
Authors: Tran Dat Q. , Tasnádi Ferenc , Žukauskaitė Agnė , Birch Jens , Darakchieva Vanya , Paskov Plamen P.
Published: May 2023

Owing to their very large piezoelectric coefficients and spontaneous polarizations, (Sc,Y)xAl1−xN alloys have emerged as a new class of III-nitride semiconductor materials with great potential for high-frequency electronic and acoustic devices. The thermal conductivity of constituent materials is a key parameter for design, optimization, and thermal management of such devices. In this study, transient thermoreflectance technique is applied to measure the thermal conductivity of ScxAl1−xN and YxAl1−xN (0 ≤x ≤0.22) layers grown by magnetron sputter epitaxy in the temperature range of 100–400 K. The room-temperature thermal conductivity of both alloys is found to decrease significantly with increasing Sc(Y) composition compared to that of AlN. We also found that the thermal conductivity of YxAl1−xN is lower than that of ScxAl1−xN for all studied compositions. In both alloys, the thermal conductivity increases with the temperature up to 250 K and then saturates. The experimental data are analyzed using a model based on the solution of the phonon Boltzmann transport equation within the relaxation time approximation. The contributions of different phonon-scattering mechanisms to the lattice thermal conductivity of (Sc,Y)xAl1−xN alloys are identified and discussed.
A field-effect transistor-based room-temperature quantum current source
Authors: Cheung Kin P. , O'Sullivan Barry J.
Published: May 2023

This work provides a proof-of-concept demonstration of the room-temperature quantum current source based on a nanoscale metal-oxide-semiconductor-field-effect-transistor (MOSFET). Using a low leakage MOSFET design, the current source achieved 1.000 11 ± 0.000 22 charges per cycle without any leakage correction scheme. The achieved accuracy is limited by noise in the very low level of measured current and by calibration uncertainty.
Compact Sparse R-CNN: Speeding up sparse R-CNN by reducing iterative detection heads and simplifying feature pyramid network
Authors: He Zihang , Ye Xiang , Li Yong
Published: May 2023

Processing a large number of proposals usually takes a significant proportion of inference time in two-stage object detection methods. Sparse regions with CNN features (Sparse R-CNN) was proposed using a small number of learnable proposals to replace the proposals derived from anchors. To decrease the missing rate, Sparse R-CNN uses six iterative detection heads to gradually regress the detection boxes to the corresponding objects, which hence increases the inference time. To reduce the number of iterative heads, we propose the iterative Hungarian assigner that encourages Sparse R-CNN to generate multiple proposals for each object at the inference stage. This decreases the missing rate when the number of iterative heads is small. As a result, Sparse R-CNN using the proposed assigner needs fewer iterative heads but gives higher detection accuracy. Also, we observe that the multi-layer outputs of the feature pyramid network contribute little to Sparse R-CNN and propose using a single-layer output neck to replace it. The single-layer output neck further improves the inference speed of Sparse R-CNN without the cost of detection accuracy. Experimental results show that the proposed iterative Hungarian assigner together with the single-layer output neck improves Sparse R-CNN by 2.5 AP50 on the Microsoft common objects in context (MS-COCO) dataset and improves Sparse R-CNN by 3.0 AP50 on the PASCAL visual object classes (VOC) dataset while decreasing 30% floating point operations (FLOPs).
Application of linear iterative methods for the proximity effect correction in electron beam lithography
Authors: Xu J. , Yang S. , Dong L. , Wei Y.
Published: May 2023

The Jacobi linear iterative method and weight Jacobi method (WJM) are introduced for solving the large-scale linear problem in the proximity effect correction (PEC) of electron beam lithography. Based on the discussion of PEC physics, a symmetrical and positive defined proximity interaction matrix is constructed to ensure the convergence of the methods. It shows that zeroing the center exposure fraction in the point spread function matrix is equal to the operation of splitting the proximity interaction matrix. Then, the Jacobi method is ready for the PEC calculation. The iterative can be performed in the Fourier domain due to the inherent parallelization of the Jacobi method. The convergent property of the Jacobi method is discussed and then testified by the PEC simulation. Compared with the classical Jacobi method, an improvement of 100% in convergence efficiency can be achieved by introducing the optimized relaxation parameter quasi-ωopt in the WJM. By combining the WJM and Gold nonlinear iteration method, a new method that shows an order of magnitude superior in accuracy to the WJM is proposed. Results indicate the methods introduced here could be used to calculate the PEC problem efficiently.
A kinetic treatment of surface plasmon polaritons in the Voigt configuration
Authors: Murtaza G. , Abbas G. , Murtaza G.
Published: May 2023

The study of microscopic effects on the dispersion of surface magnetoplasmon polaritons is important. We use the collisionless Vlasov equation and Maxwell’s equations to evaluate the dielectric tensor for evaluating the dispersion relations of surface magnetoplasmon polaritons. We treat the case in the Voigt geometry assuming a semi-infinite dielectric medium. The direction of the magnetic field is considered parallel to the surface and perpendicular to the propagation vector k. The analysis shows the influence of additional microscopic kinetic effects. Standard Drude model results are retrieved in the absence of these effects.
Toward in-fiber nonlinear silicon photonics
Authors: Shen Li , Huang Meng , Sun Shiyu , Wu Dong , Yan Zhiwei , Ren Haonan , Peacock Anna C.
Published: May 2023

Silicon core fibers (SCFs) offer an exciting opportunity to harness the nonlinear functionality of the semiconductor material within the excellent waveguiding properties of optical fiber systems. Over the past two decades, these fibers have evolved from a research curiosity into established components for use across a wide range of photonic applications. This article provides a comprehensive overview of the evolution of the SCFs, with a focus on the development of the fabrication and post-processing procedures that have helped unlock the nonlinear optical potential of this new technology. As well as reviewing the timeline of advancements in nonlinear performance, a perspective will be provided on the current challenges and future opportunities for in-fiber nonlinear silicon systems.
Superconducting pulse conserving logic and Josephson-SRAM
Authors: Herr Quentin , Josephsen Trent , Herr Anna
Published: May 2023

Superconducting digital pulse-conserving logic and Josephson static random access memory (JSRAM) memory together enable scalable circuits with energy efficiency 100× beyond leading-node CMOS. Circuit designs support high throughput and low latency when implemented in an advanced fabrication stack with high-critical-current-density Josephson junctions of 1000 μA/μm2. Pulse-conserving logic produces one single-flux-quantum output for each input and includes a three-input, three-output gate producing logical or3, majority3, and and3. Gate macros using dual-rail data encoding eliminate inversion latency and produce efficient implementations of all standard logic functions. A full adder using 70 Josephson junctions has a carry-out latency of 5 ps corresponding to an effective 12 levels of logic at 30 GHz. JSRAM memory uses single-flux-quantum signals throughout an active array to achieve throughput at the same clock rate as the logic. The unit cell has eight Josephson junctions, a signal propagation latency of 1 ps, and a footprint of 2 μm2. Projected density of JSRAM is 4 MB/cm2, and computational density of pulse-conserving logic is on par with leading node CMOS accounting for power densities and clock rates.
Temperature-dependent Poole–Frenkel transport properties of the SrSnO3/Nb-doped SrTiO3 heterostructure
Authors: Niu R. F. , Wang D. P. , Cui L. Q. , Wang W. T.
Published: May 2023

All-perovskite oxide heterostructure of SrSnO3/Nb-doped SrTiO3 was fabricated by using the pulsed laser deposition method. Unusual transport properties of the interface between SrSnO3 and Nb-doped SrTiO3 have been investigated at temperatures from 100 to 300 K. A diodelike rectifying behavior has been demonstrated by the temperature-dependent current–voltage (IV) measurements. The forward current showed typical IV characteristics of p–n junctions or Schottky diodes and was perfectly fitted using the thermionic emission model. At the reverse bias, however, the temperature-dependent IV curves developed in the opposite direction, indicating the tunneling effects on the interface. The Poole–Frenkel emission was used to explain this electrical transport mechanism under the reverse voltages.
Adsorption of aluminum via surface modification: An effective way to reduce the aluminum contamination presented in H2O2 plasma sterilization
Authors: Hou Ruixiang , Li Xiaomin , Gao Ang , Zhao Muhua , Zhang Yang , Xie Ziang , Zhang Chuangnian , Zhang Yan , Zheng Cui , Guo Zifang
Published: May 2023

In our recent work, it was first demonstrated that aluminum (Al) ions generated in the process of H2O2 plasma sterilization can penetrate the sterilization package and contaminate the surgical instrument inside. In this paper, it is first reported that Al ions can be adsorbed in plasma by sterilization package with surface modification, significantly reducing the contamination, up to 92%. The surface modification is carried out by introducing a functional layer on the surface of the sterilization package. The special chemical groups in the functional layer can combine with Al ions in two ways, ion exchange and chelation, preventing them from contaminating the surgical instrument in the sterilization package. Through the research on the diffusion coefficient of Al in Si sterilized using the modified sterilization packages, it is found that surface modification of sterilization packages has a great influence on the physical mechanism of Al contamination.