NEGATIVE ION PHOTOELECTRON SPECTROSCOPY: ELECTRONIC STRUCTURES, CHEMICAL BONDING, MOLECULAR ACTIVATION, AND ELECTRON-MOLECULE INTERACTIONS

Negative ion photoelectron spectroscopy has been applied to address a broad range of fundamental problems in chemistry. Major topics that have been studied are related to electronic structures, chemical bonding, molecular activation, and electron-molecule interactions. New phenomena have been discovered, including but not limited to, the fine-tunability of the electronic spectra in superatoms, realization of Lewis basic sodium anion, halogen-bond stabilized anions, selective methane activation by single atomic anions, and excess electrons tethered by weak attractive interactions. The insight acquired from negative ion photoelectron spectroscopy has provided understanding into the above-mentioned topics at a molecular level

CO2 Hydrogenation to Formate and Formic Acid by Bimetallic Palladium-Copper Hydride Clusters.

Mass spectrometric analysis of the anionic products of interaction between bimetallic palladium-copper tetrahydride anions, PdCuH4-, and carbon dioxide, CO2, in a reaction cell shows an efficient generation of the PdCuCO2H4- intermediate and formate/formic acid complexes. Multiple structures of PdCuH4- and PdCuCO2H4- are identified by a synergy between anion photoelectron spectroscopy and quantum chemical calculations. The higher energy PdCuH4- isomer is shown to drive the catalytic hydrogenation of CO2, emphasizing the importance of accounting for higher energy isomers for cluster catalytic activity. This study represents the first example of CO2 hydrogenation by bimetallic hydride clusters

Effect of Quench Polish Quench Nitriding Temperature on the Microstructure and Wear Resistance of SAF2906 Duplex Stainless Steel

The effect of quench polish quench (QPQ) nitriding temperature on the microstructure and wear resistance of SAF2906 duplex stainless steel was investigated. Results showed the surface of the nitrided samples was composed of an oxidized layer, a loose compound layer, a compact compound layer, and a diffusion layer. The oxidized layer was composed of Fe3O4. The main phases of the loose compound layer were CrN, alpha(N), Fe2-3N, and Fe3O4. The compact compound layer was composed of CrN, alpha(N), and Fe2-3N. In the diffusion layer, CrN and expanded austenite (S) were the main phases. The nitrided layer thickness increased from 20 to 41 mu m with an increasing temperature of 570 to 610 degrees C. When the nitriding temperature was above 590 degrees C, the precipitates in the diffusion layer became coarsened, and their morphologies gradually changed from spherical particulate to rod-like and flocculent-like. Tribotests showed the cumulative mass loss of QPQ-treated samples was much lower than that of the substrate. The cumulative mass loss of the samples nitrided at 610 degrees C was higher than that at 570 degrees C during the first 29 h. When the test time was over 29 h, the former was lower than the latter

Stabilizing Otherwise Unstable Anions with Halogen Bonding

Both hydrogen bonding (HB) and halogen bonding (XB) are essentially electrostatic interactions, but whereas hydrogen bonding has a well-documented record of stabilizing unstable anions, little is known about halogen bonding's ability to do so. Herein, we present a combined anion photoelectron spectroscopic and density functional theory study of the halogen bond-stabilization of the pyrazine (Pz) anion, an unstable anion in isolation due to its neutral counterpart having a negative electron affinity (EA). The halogen bond formed between the σ-hole on bromobenzene (BrPh) and the lone pair(s) of Pz significantly lowers the energies of the Pz(BrPh)_1− and Pz(BrPh)_2− anions relative to the neutral molecule, resulting in the emergence of a positive EA for the neutral complexes. As seen through its charge distribution and electrostatic potential analyses, the negative charge on Pz− is diluted due to the XB. Thermodynamics reveals that the low temperature of the supersonic expansion plays a key role in forming these complexes

Classifying Normal and Abnormal Status Based on Video Recordings of Epileptic Patients

Based on video recordings of the movement of the patients with epilepsy, this paper proposed a human action recognition scheme to detect distinct motion patterns and to distinguish the normal status from the abnormal status of epileptic patients. The scheme first extracts local features and holistic features, which are complementary to each other. Afterwards, a support vector machine is applied to classification. Based on the experimental results, this scheme obtains a satisfactory classification result and provides a fundamental analysis towards the human-robot interaction with socially assistive robots in caring the patients with epilepsy (or other patients with brain disorders) in order to protect them from injury

MTANS:Multi-Scale Mean Teacher Combined Adversarial Network with Shape-Aware Embedding for Semi-Supervised Brain Lesion Segmentation

The annotation of brain lesion images is a key step in clinical diagnosis and treatment of a wide spectrum of brain diseases. In recent years, segmentation methods based on deep learning have gained unprecedented popularity, leveraging a large amount of data with high-quality voxel-level annotations. However, due to the limited time clinicians can provide for the cumbersome task of manual image segmentation, semi-supervised medical image segmentation methods present an alternative solution as they require only a few labeled samples for training. In this paper, we propose a novel semi-supervised segmentation framework that combines improved mean teacher and adversarial network. Specifically, our framework consists of (i) a student model and a teacher model for segmenting the target and generating the signed distance maps of object surfaces, and (ii) a discriminator network for extracting hierarchical features and distinguishing the signed distance maps of labeled and unlabeled data. Besides, based on two different adversarial learning processes, a multi-scale feature consistency loss derived from the student and teacher models is proposed, and a shape-aware embedding scheme is integrated into our framework. We evaluated the proposed method on the public brain lesion datasets from ISBI 2015, ISLES 2015, and BRATS 2018 for the multiple sclerosis lesion, ischemic stroke lesion, and brain tumor segmentation respectively. Experiments demonstrate that our method can effectively leverage unlabeled data while outperforming the supervised baseline and other state-of-the-art semi-supervised methods trained with the same labeled data. The proposed framework is suitable for joint training of limited labeled data and additional unlabeled data, which is expected to reduce the effort of obtaining annotated images

Suitable fertilization can improve maize growth and nutrient utilization in ridge-furrow rainfall harvesting cropland in semiarid area

The ridge-furrow rainfall harvesting system (RFRH) improved the water shortages, and reasonable fertilization can promote nutrient uptake and utilization of crops, leading to better yield in semi-arid regions. This holds significant practical significance for improving fertilization strategies and reducing the application of chemical fertilizers in semi-arid areas. This field study was conducted to investigate the effects of different fertilization rates on maize growth, fertilizer use efficiency, and grain yield under the ridge-furrow rainfall harvesting system during 2013-2016 in semiarid region of China. Therefore, a four-year localization field experiment was conducted with four fertilizer treatments: RN (N 0 kg hm-2, P2O5 0 kg hm-2), RL (N 150 kg hm-2, P2O5 75 kg hm-2), RM (N 300 kg hm-2, P2O5 150 kg hm-2), and RH (N 450 kg hm-2, P2O5 225 kg hm-2). The results showed that the total dry matter accumulation of maize increased with the fertilizer application rate. The nitrogen accumulation was highest under the RM treatment after harvest, average increase by 1.41% and 22.02% (P<0.05) compared to the RH and RL, respectively, whereas the phosphorus accumulation was increased with the fertilizer application rate. The nitrogen and phosphorus use efficiency both decreased gradually with the fertilization rate increased, where the maximum efficiency was observed under the RL. With the increase of fertilizer application rate, the maize grain yield initially increased and then decreased. Under linear fitting, the grain yield, biomass yield, hundred-kernel weight, and ear-grain number all showed a parabolic trend with the increase of fertilization rate. Based on comprehensive consideration, the recommended moderate fertilization rate (N 300 kg hm-2, P2O5 150 kg hm-2) is suitable for the ridge furrow rainfall harvesting system in semiarid region, and the fertilization rate can be appropriately reduced according to the rainfall

Impact of environmental comfort on urban vitality in small and medium-sized cities: A case study of Wuxi County in Chongqing, China

China's urbanization has exceeded 64% and a large number of small and medium-sized cities are the key development areas in the new stage. In urban planning, it is very important to reveal the influence of environmental comfort on urban vitality to improve the life quality of residents in these towns. Thus, the study investigated the impact of environmental comfort on urban vitality using ordinary least squares regression in Wuxi County. Environmental comfort was assessed through a comprehensive analysis of a built-up area and urban vitality was represented by vitality intensity. In addition, the influence pathways were identified and model validation was verified. The conclusions are as follows: (1) Environmental comfort and urban vitality are distributed spatially similarly, and both gradually decline from the center to the periphery. It is high in the east and low in the west, high in the south and low in the north. (2) Population density, POI mixing degree, building density, and road network density have significant positive effects on urban vitality. Population density has the greatest impact on urban vitality. Building height, building age, and river buffer have significant negative effects on urban vitality. (3) The impact of comprehensive environmental comfort on urban vitality is positive, and in terms of time, the order of impact is afternoon > morning > evening. Finally, a method for assessing the impact of environmental comfort on urban vitality was constructed, and the promoting effect of environmental comfort improvements on the vitality was verified. These findings will fill the gap between urban physical space and social needs in planning practices and provide reference to improve vitality for urban planning in small and medium-sized cities

Pengembangan Media Pembelajaran Fisika Berupa Buletin Dalam Bentuk Buku Saku Untuk Pembelajaran Fisikakelas VIII Materi Gaya Ditinjau Dari Minat Baca Siswa

Tujuan dari penelitian ini untuk mengembangkan media pembelajaran berupa buletin dalam bentuk buku saku untuk pembelajaran Fisika kelas VIII pada materi Gaya ditinjau dari aspek materi, konstruk, dan bahasa serta minat baca siswa. Penelitian ini termasuk penelitian pengembangan yang menggunakan metode Research and Development (R&D). Penelitian ini menggunakan model pengembangan model prosedural yaitu model yang bersifat deskriptif yang menunjukkan tahapan-tahapan yang harus diikuti untuk menghasilkan produk berupa media pembelajaran.Jenis data yang diperoleh bersifat kualitatif dan kuantitatif yaitu angket dan wawancara. Teknik analisis data yang digunakan adalah analisis deskriptif kualitatif dan kuantitatif. Hasil penelitian menunjukkan bahwa media pembelajaran yang dikembangkan berupa buletin Fisika dalam bentuk buku saku memiliki kriteria sangat baik berdasarkan penilaian dari ahli materi, ahli bahasa Indonesia, dan ahli media memberikan rata-rata penilaian sebesar 86,56%. Media pembelajaran yang dikembangkan juga memiliki kriteria sangat baik bila ditinjau dari peningkatan minat baca siswa. Hal ini terbukti pada hasil angket minat baca awal dan akhir yang diberikan kepada siswa yang memberikan rata-rata peningkatan sebesar 11,13%. Selain itu juga dianalisis dengan menggunakan uji-t berpasangan terhadap data masing-masing kelompok uji coba untuk mengetahui signifikansi dari peningkatan minat baca siswa. Untuk uji coba perorangan diperoleh hasil perhitungan thitung = 6,957 > ttabel = 1,943 dan nilai Sig. = 0,001 < 0,05 yang berarti sangat signifikan. Untuk kelompok kecil didapatkan hasil perhitungan bahwa thitung = 7,848 > ttabel = 1,725 dan nilai Sig. = 0,000 < 0,05 yang berarti sangat signifikan. Untuk kelompok besar juga didapatkan hasil perhitungan bahwa thitung = 20,214 > ttabel = 1,725 dan nilai Sig. = 0,000 < 0,05 yang berarti sangat signifikan. Simpulan dari penelitian ini adalah media pembelajaran berupa buletin dalam bentuk buku saku memiliki kriteria sangat baik bila ditinjau dari aspek materi, konstruk, dan bahasa serta minat baca siswa