Mega-NeRF++: An Improved Scalable NeRFs for High-resolution Photogrammetric Images

Over the last few years, implicit 3D representation has attracted more and more research endeavors, typified by the so-called Neural Radiance Fields (NeRF). The original NeRF and some relevant variants mostly address on small-scale scene (such as, indoor or tiny toys), which already show good novel views rendering results. It still remains challenging when dealing with wide coverage area that is captured by large number of high-resolution images, the time efficiency and rendering quality is generally limited. To cope with large-scale scenario, recently, Mega-NeRF was proposed to divide the area into several overlapping sub-area and train corresponding sub-NeRFs, respectively. Mega-NeRF adopts the method of parallel training of multiple sub-modules, which means sub-modules are absolutely independent of each other, which might in principle not be an optimal solution, as two sub-NeRFs of adjacent sub-models obtained by parallel training are likely to get different rendering results for the overlapping area, and the final rendering result is supposed to be negative affected. Therefore, we present Mega-NeRF++, and our goal is to improve Mega-NeRF by implementing extra sub-models optimization that alleviate the rendering discrepancy of overlapping sub-NeRFs. More specifically, we further fine tune the original Mega-NeRFs by considering the consistency of adjacent overlapping area, which means the training data used in the optimization are only from the overlapping region, and we also proposed a novel loss, so that it not only takes into account the difference between the prediction of each sub-model and the true value, but also considers the consistency of the predicted results between various adjacent sub-modules in the overlapping region. The experimental results show that, for the overlapping area, our Mega-NeRF++ can qualitatively render better images with higher fidelity and quantitively have higher PNSR and SSIM compare to original Mega-NeRF

Weakly Supervised Learning Method for Semantic Segmentation of Large-Scale 3D Point Cloud Based on Transformers

Nowadays, semantic segmentation results of 3D point cloud have been widely applied in the fields of robotics, autonomous driving, and augmented reality etc. Thanks to the development of relevant deep learning models (such as PointNet), supervised training methods have become hotspot, in which two common limitations exists: inferior feature representation of 3D points and massive annotations. To improve 3D point feature, inspired by the idea of transformer, we employ a so-call LCP network that extracts better feature by investigating attentions between target 3D points and its corresponding local neighbors via local context propagation. Training transformer-based network needs amount of training samples, which itself is a labor-intensive, costly and error-prone work, therefore, this work proposes a weakly supervised framework, in particular, pseudo-labels are estimated based on the feature distances between unlabeled points and prototypes, which are calculated based on labeled data. The extensive experimental results show that, the proposed PL-LCP can yield considerable results (67.6% mIOU for indoor and 67.3% for outdoor) even if only using 1% real labels, and comparing to several state-of-the-art method using all labels, we achieve superior results in mIOU, OA for indoor (65.9%, 89.2%)

Inverse Optical Cavity Design for Ultrabroadband Light Absorption Beyond the Conventional Limit in Low-Bandgap Nonfullerene Acceptor–Based Solar Cells

In the subwavelength regime, several nanophotonic configurations have been proposed to overcome the conventional light trapping or light absorption enhancement limit in solar cells also known as the Yablonovitch limit. It has been recently suggested that establishing such limit should rely on computational inverse electromagnetic design instead of the traditional approach combining intuition and a priori known physical effect. In the present work, by applying an inverse full wave vector electromagnetic computational approach, a 1D nanostructured optical cavity with a new resonance configuration is designed that provides an ultrabroadband (˜450 nm) light absorption enhancement when applied to a 107 nm thick active layer organic solar cell based on a low-bandgap (1.32 eV) nonfullerene acceptor. It is demonstrated computationally and experimentally that the absorption enhancement provided by such a cavity surpasses the conventional limit resulting from an ergodic optical geometry by a 7% average over a 450 nm band and by more than 20% in the NIR. In such a cavity configuration the solar cells exhibit a maximum power conversion efficiency above 14%, corresponding to the highest ever measured for devices based on the specific nonfullerene acceptor used.Peer ReviewedPostprint (author's final draft

Karriere-Handbuch

We design and synthesize four fused-ring electron acceptors based on 6,6,12,12-tetrakis(4-hexylphenyl)- indacenobis(dithieno[3,2-b;2′,3′-d]thiophene) as the electron- rich unit and 1,1-dicyanomethylene-3-indanones with 0− 2 fluorine substituents as the electron-deficient units. These four molecules exhibit broad (550−850 nm) and strong absorption with high extinction coefficients of (2.1−2.5) × 105 M−1 cm−1. Fluorine substitution downshifts the LUMO energy level, red-shifts the absorption spectrum, and enhances electron mobility. The polymer solar cells based on the fluorinated electron acceptors exhibit power conversion efficiencies as high as 11.5%, much higher than that of their nonfluorinated counterpart (7.7%). We investigate the effects of the fluorine atom number and position on electronic properties, charge transport, film morphology, and photovoltaic properties

Performance Evaluation of CO2 Huff-n-Puff Gas Injection in Shale Gas Condensate Reservoirs

When the reservoir pressure is decreased lower than the dew point pressure in shale gas condensate reservoirs, condensate would be formed in the formation. Condensate accumulation severely reduces the commercial production of shale gas condensate reservoirs. Seeking ways to mitigate condensate in the formation and enhance both condensate and gas recovery in shale reservoirs has important significance. Very few related studies have been done. In this paper, both experimental and numerical studies were conducted to evaluate the performance of CO2 huff-n-puff to enhance the condensate recovery in shale reservoirs. Experimentally, CO2 huff-n-puff tests on shale core were conducted. A theoretical field scale simulation model was constructed. The effects of injection pressure, injection time, and soaking time on the efficiency of CO2 huff-n-puff were examined. Experimental results indicate that condensate recovery was enhanced to 30.36% after 5 cycles of CO2 huff-n-puff. In addition, simulation results indicate that the injection period and injection pressure should be optimized to ensure that the pressure of the main condensate region remains higher than the dew point pressure. The soaking process should be determined based on the injection pressure. This work may shed light on a better understanding of the CO2 huff-n-puff- enhanced oil recovery (EOR) strategy in shale gas condensate reservoirs

A Fully Coupled Gas–Water–Solids Mathematical Model for Vertical Well Drainage of Coalbed Methane

The coupling relationship between the deformation field, the diffusion field, and the seepage field is an important factor in fluid transport mechanisms in the long-term coalbed methane (CBM) exploitation process. A mathematical model of gas–water two-phase fluid–structure coupling in a double-porosity medium in coal reservoirs is established in this paper. Taking Hancheng Block, a typical production block in Qinshui Basin, as the geological background critical desorption pressure, reservoir permeability anisotropy is considered in the model. COMSOL Multiphysics (COMSOL_6.0) was used to create the model. The accuracy and rationality of the model were verified by comparing field production data with the results of the simulation. Using the simulation, the influence law of various reservoir geological characteristics parameters (Langmuir strain constant, ratio of critical desorption pressure to reservoir pressure of coal seam (CDPRP), elastic modulus, initial water saturation, Langmuir pressure, etc.) on CBM productivity, reservoir pressure, and permeability ratio was discussed, and a thorough analysis of the factors affecting productivity was obtained using the orthogonal test method. The findings of this study indicate that the change in permeability is the result of the superposition effect of many factors. Different stages of drainage have different primary regulating factors. Rock skeleton stress has a consequence on coal matrix permeability in the early drainage stage, and coal matrix shrinkage is primarily impacted in the later drainage stage. Besides the initial water saturation, other reservoir geological parameters (e.g., CDPRP, Langmuir volume, Langmuir strain constant, elastic modulus) have a strong relationship with productivity. When the value of coal geological parameters increases, the degree of productivity release is higher (as the initial water saturation increases, the production decreases correspondingly). Different coal and rock parameters have varying levels of impact on the drainage stage of CBM wells. The influences of the CDPRP, Langmuir volume, Langmuir strain constant, and elastic modulus on gas production are mainly concentrated in the initial and intermediate drainage stages and begin to fall off during the last drainage stage. Per the multi-factor analysis, the main coal–rock parameters affecting the productivity release are the Langmuir strain constant, followed by the CDPRP and other parameters. The analysis findings can offer theoretical guidance for CBM well selection and layer selection and enhance the block’s overall CBM development level. The improved productivity prediction model for CBM, which is based on fluid–structure coupling theory, can offer a new technical benchmark for CBM well productivity prediction

Biotin and Leucine Alone or in Combination Promoted the Synthesis of Odd- and Branched-Chain Fatty Acids in the Rumen In Vitro

The odd- and branched-chain fatty acids (OBCFA) accumulated in ruminant products are a class of beneficial fatty acids for human health. Since biotin and leucine are involved in OBCFA synthesis, this study aimed to evaluate their effect on OBCFA synthesis in vitro. There were four treatments: the control group that only provided the basal diet, or the basal diet supplemented with biotin (4 mg/kg dry matter, DM), leucine (4 g/kg DM), or a combination of biotin (4 mg/kg DM) and leucine (4 g/kg DM). The results showed that biotin promoted the degradation of DM (p p iso, total anteiso, total branched-chain fatty acids, total OBCFA, and total fatty acids were significantly increased by the supplementation of biotin or leucine (p p < 0.05). In conclusion, the results of this study suggested that biotin and leucine can be used as effective nutrition strategies to promote OBCFA synthesis

Effects of Dietary Supplementation with Clostridium butyricum on Growth Performance, Serum Immunity, Intestinal Morphology, and Microbiota as an Antibiotic Alternative in Weaned Piglets

This study investigated the effects of Clostridium butyricum (C. butyricum) use on growth performance, serum immunity, intestinal morphology, and microbiota as an antibiotic alternative in weaned piglets. Over the course of 28 days, 120 piglets were allocated to four treatments with six replicates of five piglets each. The treatments were: CON (basal diet); AGP (basal diet supplemented with 0.075 g/kg chlortetracycline, 0.055 g/kg kitasamycin, and 0.01 g/kg virginiamycin); CBN (basal diet supplemented with normal dosage of 2.5 &times; 108 CFU/kg C. butyricum); and CBH (basal diet supplemented with high dosage of 2.5 &times; 109 CFU/kg C. butyricum). Body weight (BW) and feed consumption were recorded at the beginning and on days 14 and 28 of the experiment, and representative feed samples and fresh feces were collected from each pen between days 26 and 28. Average fecal score of diarrhea was visually assessed each morning during the experimental period. On the morning of days 14 and 28, blood samples were collected to prepare serum for immune and antioxidant parameters measurement. One male piglet close to the average group BW was selected from each replicate and was slaughtered on day 21 of the experiment. Intestinal crypt villi, and colonic microbiota and its metabolites short-chain fatty acids were measured. Compared to the CON group, the CBN and AGP groups significantly decreased (p &lt; 0.05) the ratio of feed to weight gain by 8.86% and 8.37% between days 1 and 14, 3.96% and 13.36% between days 15 and 28, 5.47% and 11.44% between days 1 and 28. Dietary treatment with C. butyricum and AGPs significantly decreased the average fecal score during the experimental period (p &lt; 0.05). The apparent total tract digestibility of dry matter, organic matter, and total carbohydrates in the CBH group were higher respectively at 3.27%, 2.90%, and 2.97%, than those in the CON or AGP groups (p &lt; 0.05). Compared to the CON group, the CBH group significantly increased short-chain fatty acids in colon and villus height in the jejunum (p &lt; 0.05). The CBN group had higher serum levels of immunoglobulins, interleukin 2 (IL-2), and glutathione peroxidase (GSH-PX) activity, but lower serum levels of IL-1&beta; and IL-6, and a lower aspartate aminotransferase (AST), alkaline phosphatase (ALP), and gamma-glutamyl transpeptidase (&gamma;-GT) activity (p &lt; 0.05), while compared to the CON group. Dietary treatment with C. butyricum significantly increased the relative abundance of Streptococcus and Bifidobacterium (p &lt; 0.05). In summary, diet with C. butyricum increased the growth performance and benefited the health of weaned piglets

Evaluating the Effect of MgO/Al2O3 Ratio on Thermal Behaviors and Structures of Blast Furnace Slag with Low Carbon Consumption

In order to clarify the effect of the MgO/Al2O3 ratio on the fluidity of a low-alumina blast furnace slag system, the influence law of slag fluidity with different MgO/Al2O3 ratios was studied based on the composition of blast furnace slag through a viscosity experiment and themodynamic software. By studying the effect of the MgO/Al2O3 ratio on the activation energy of viscous flow of slag combined with FT-IR, the effect of the MgO/Al2O3 ratio on the thermal-stability of low-aluminum slag was interpreted from the microstructure level. Results indicated that the viscosity and the melting temperature of slag both showed a gradual downward trend due to the increase of the MgO/Al2O3 ratio. Besides, the temperature stability of the low aluminum slag became more stable due to the depolymerization of the complex structure of slag. Considering the actual operating conditions of blast furnace, the MgO/Al2O3 ratio of slag was suggested to be controlled to 0.60 and the basicity to be no higher than 1.20 under the conditions of this investigation. Industrial test results showed that the coke rate could be saved as 3.49 kg/t when the MgO/Al2O3 ratio decreased from 0.70 to 0.58

Transfer of β‐agonists from animal feed into Tricholoma gambosum through manure

Abstract Fungi are dependent on animal manure as a cultivation medium and may be vulnerable to feed‐derived β‐agonist contamination. To test whether β‐agonists incorporated in animal feed can transport into fungi through manure, a greenhouse study was conducted with Tricholoma gambosum grown in a culture medium amended with medicated cattle manure. Cattle were orally administrated with a single (ractopamine, 670.0 μg/kg BW/day) or a mixture of β‐agonists (clenbuterol, ractopamine, and salbutamol at the doses of 5.3, 223.3, and 50.0 μg/kg BW/day, respectively) for 28 days. Three batches of T. gambosum were harvested. A liquid chromatography tandem mass spectrometry‐based method was developed to quantify the number of β‐agonists taken up by T. gambosum from animal manure. The analytical recoveries for β‐agonists were between 66.61% and 91.78% with relative standard deviations between 1.70% and 12.18%, and the limit of quantification (LOQ) was 0.3 ng/g. The ractopamine residues in T. gambosum from batch 1 were 1.3 ng/g and were below the LOQ in batches 2 and 3 in the single treatment group. In the mixed treatment group, ractopamine concentrations were 0.42 and 0.50 ng/g in batches 1 and 2, respectively, and the salbutamol concentration was 1.94 ng/g in batch 1, while clenbuterol was undetectable in all three batches. These results indicated that the β‐agonists transferred to T. gambosum in trace amounts and presented a limited risk to consumers