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1.
Retrieving 3D shapes with 2D images has become a popular research area nowadays, and a great deal of work has been devoted to reducing the discrepancy between 3D shapes and 2D images to improve retrieval performance. However, most approaches ignore the semantic information and decision boundaries of the two domains, and cannot achieve both domain alignment and category alignment in one module. In this paper, a novel Collaborative Distribution Alignment (CDA) model is developed to address the above existing challenges. Specifically, we first adopt a dual-stream CNN, following a similarity guided constraint module, to generate discriminative embeddings for input 2D images and 3D shapes (described as multiple views). Subsequently, we explicitly introduce a joint domain-class alignment module to dynamically learn a class-discriminative and domain-agnostic feature space, which can narrow the distance between 2D image and 3D shape instances of the same underlying category, while pushing apart the instances from different categories. Furthermore, we apply a decision boundary refinement module to avoid generating class-ambiguity embeddings by dynamically adjusting inconsistencies between two discriminators. Extensive experiments and evaluations on two challenging benchmarks, MI3DOR and MI3DOR-2, demonstrate the superiority of the proposed CDA method for 2D image-based 3D shape retrieval task.  相似文献   
2.
在液压支架对接焊缝缺陷的检测中,传统的超声相控阵二维检测得到的缺陷信息单一,无法直观反映缺陷在三维空间中的位置、形态及尺寸。采用全聚焦相控阵三维成像技术对对接焊缝中的缺陷进行检测。设计了含有内部裂纹、根部未焊透、夹渣3种缺陷的试块,分别用线阵探头与面阵探头对试块进行了检测,以此来验证全聚焦三维成像对缺陷的检测效果。通过比较得出,全聚焦三维成像能够更准确地检测出缺陷的位置、大小信息。  相似文献   
3.
大排田岩体位于粤北澜河铀矿集区内,对研究区内大排田岩体粗中粒斑状黑云母花岗岩进行了详细的岩相学和地球化学分析,以探讨其岩石成因、岩浆源区及与铀成矿的关系。结果表明,大排田岩体中粗粒斑状黑云母花岗岩具有高SiO2(73.6%~76.5%),富Al2O3(12.4%~13.5%)、富碱(K2O=5.21%~5.63%,Na2O=2.44%~2.76%),且钾大于钠,贫MgO(0.23%~0.52 %)、铝饱和指数(A/CNK)为1.30~1.56,FeOt/MgO为3.21~6.61,属于高钾钙碱性过铝质花岗岩。大排田岩体微量元素显示了Rb、Th、U、Ta相对富集, Ba、Nb、Sr等元素相对亏损特征。稀土元素配分模式总体呈右倾型,轻重稀土分馏明显,轻稀土相对富集(112×10-6~245×10-6),重稀土相对亏损(26.7×10-6~53.3×10-6),Eu显示了负异常特征。上述地球化学特征指示其具有A2型花岗岩特征。推测其形成于拉张构造背景下,由变泥质沉积岩发生部分熔融形成的。  相似文献   
4.
Pt–MoO3 was synthesized by microwave-assisted chemical reduction. The physicochemical characterization showed that the electrocatalyst contained nanoparticles of Pt and clusters of MoO3. The average particle size of the catalytic material was 2.5 nm. The electrochemical results showed that the Pt–MoO3/C was suitable to carry out the electrooxidation reactions of ethanol and methanol indistinctly, avoiding CO poisoning. It was possible to compare the results with commercial Pt/C. The synthesized material showed a better electrochemical performance. Different simulations were performed using the Nernst equation to evaluate the influence of temperature, internal resistance, and the current density losses as a function of the fuel used. The theoretical results indicated that the electrical power of the mono-cell improves by 21.5% when the energy vector is changed from methanol to ethanol at the maximum power point, obtaining an electrical potential change ΔE = 87.02 mV and a variation of the electric power of Δp = 114.14 mW cm?2. The use of dual fuels could improve the performance of experimental fuel cells.  相似文献   
5.
硫酸盐法制浆企业的碳排放及碳捕获与利用技术   总被引:2,自引:2,他引:0       下载免费PDF全文
本文首先介绍了硫酸盐浆厂生产纸浆过程中CO2的排放来源,进一步分析了“林浆一体化”企业的整体碳足迹,然后综述了温室气体排放核算方法,并介绍了硫酸盐浆厂的CO2捕获及利用技术研究进展,包括黑液中酸析木质素的生产、沉淀碳酸钙的生产、塔罗油的提取、木质素纳米颗粒的生产等。最后探讨了将硫酸盐浆厂与生物质精炼厂相结合以进一步降低碳排放的可能性。  相似文献   
6.
针对货运列车在神华铁路日常的运营过程中,车辆车体受外界及自身磨耗等因素的影响,而造成车体破损、车体仓门缝隙过大,甚至出现严重破损等故障。而故障诊断是实现铁路科学维修决策的重要依据。本文提出了一种利用3D图像检测技术,进行货车车体故障数据处理和诊断的方法。引入主流成像技术,提出一种采用三维图像采集方式,用于覆盖车体整个侧部表明图像的拍摄。进行了车体数据采集、3D深度数据分析、数据测试,并通过实验验证了方法的有效性。  相似文献   
7.
由于色谱分离需要耗费大量的时间,导致传统LC-MS研究中药成分的分析通量较低,而多级质谱全扫描(MS/MSALL)采用了气态分段技术(GPF),可以在直接注射(DI)模式下,采集每个表观质量数MS1信号的MS2图谱,实现MS1-MS2数据列表的高通量构建。为快速表征枸杞子化学成分组,本研究采用DI-MS/MSALL全面采集枸杞子提取物中各化学成分的多级质谱数据,根据高分辨MS1和MS2碎片离子信息推导质谱裂解途径,结合数据库检索以及相关文献,从枸杞子中初步鉴定了38个化学成分,包括1个氨基酸类、19个有机酸类、2个糖脂类、6个苯丙素类、1个黄酮类、6个生物碱类以及3个酰胺类化合物。DI-MS/MSALL可作为中药等复杂体系快速全面定性分析的有力工具。  相似文献   
8.
Hydrogen peroxide (H2O2) has been listed as one of the 100 most important chemicals in the world. However, huge amount of residual H2O2 is hard to timely decomposed into O2 and H2O under acidic condition, easily resulting in explosion hazard. Here, we reported a core–shell structure catalyst, that is graphene with Co N structure encapsulated Co nanoparticles. Co N graphene shell serves as the active site for the H2O2 decomposition, and Co core further enhance this decomposition. Benefiting from it, the H2O2 decomposition were close to 100% after 6 cycles without pH adjustment, which increased 6 orders of magnitude compared with no catalyst. At the same time, the O2 generation reached 99.67% in 2 h with little metal leaching, and ·OH has been greatly inhibited to only 0.08%. This work can cleanly remove H2O2 with little deep oxidation and protect the process of H2O2 utilization to achieve a safer world.  相似文献   
9.
A double pyrovanadate CaMgV2O7 sample was synthesized via a facile solid-state route under an air atmosphere. The nonequilibrium formation pathways of the CaMgV2O7 were investigated via powder X-ray diffraction. A multistep reactions path (metavanadates–pyrovanadates–double pyrovanadate CaMgV2O7) was proposed to describe the formation of the CaMgV2O7 considering the thermodynamic and kinetic factors. The cell unit parameters of the CaMgV2O7 sample indicated the crystallization according to a monoclinic system with space group P12/c1(14), and the lattice parameters of a = 6.756 Å, b = 14.495 Å, c = 11.253 Å, β = 99.12, and V = 108.806 Å3. X-ray photoelectron spectroscopy also confirmed the +5 oxidation state vanadium in CaMgV2O7. The endothermic effects at 1033 and 1143 K were related to the incongruent melting and liquidus temperatures of CaMgV2O7, respectively. The comprehensive thermodynamic properties of CaMgV2O7 were established in both low- and high-temperature regions, utilizing a physical property measurement system and multi-high-temperature calorimetry (96 lines). The heat capacity (200 J mol K−1) and entropy (198 J mol K−1) at 298.15 K were computed based on the low-temperature heat capacity values, and the enthalpy of formation at 298.15 K was also estimated. The fitted high-temperature capacity can be used to obtain the changes in the enthalpy, entropy, and Gibbs free energy. This study is part of building a reliable thermodynamic database of the CaO–MgO–V2O5 system.  相似文献   
10.
This work describes facile synthesis of a porous polymeric material ( T-HCP ) using readily available reagents. Specifically, T-HCP is a thermally stable and hypercrosslinked polymer (HCP) that is essentially microporous with a high BET specific surface area (940 m2 g?1). Triptycene based polymers are known to feature internal free volume. Thus, the incorporation of triptycene units and extensive crosslinking by an external cross-linker in T-HCP makes it a promising adsorbent for small gas capture applications. Experimental results show that T-HCP demonstrated good CO2 capture capacity of 132 mg g?1 (273 K, 1 bar). Molecular hydrogen storage capacity of T-HCP is estimated to be 17.7 mg g?1 (77 K, 1 bar). T-HCP revealed high CO2/N2 selectivity (up to 63) as well as promising CO2/CH4 (up to 9.1) selectivity suggesting its potential applicability for CO2 separation from flue and natural gases.  相似文献   
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