二元过渡金属团簇V-Co化学键的量化研究

用量子化学从头算方法对过渡金属原子二聚体V2 、Co2 ,双金属VCo及其二聚体 (VCo) 2 的各种组态及化学键 ,在HF Lanl2DZ水平进行了研究 ,并用MP2作了电子相关能校正 .计算结果表明 :V2 的五种可能电子组态中 ,3 Σg态最稳定 ,Co2 则是 5重态更稳定 .VCo金属对中 ,V与Co的前线轨道相似 ,均为sd3 杂化 ,可形成 1～ 7重态的电子组态 ,其中单态、七重态较稳定 .比较 (VCo) 2 二聚体的 12种异构体的几何构型与化学键 ,发现直线、折线型结构中有强弱交替的定域键 ,而菱形结构的 (VCo) 2 则是正常的金属

ContractGuard：面向以太坊區塊鏈智能合約的入侵檢測系統

以太坊智能合約本質上是一種在網絡上由相互間沒有信任關系的節點共同執行的已被雙方認證程序。目前,大量的智能合約被用于管理數字資產,使智能合約成為黑客的重要攻擊對象。常見的攻擊方法是通過利用智能合約的漏洞來實現特定操作的入侵攻擊。ContractGuard是首次提出面向以太坊區塊鏈智能合約的入侵檢測系統,它能檢測智能合約的潛在攻擊行為。ContractGuard的入侵檢測主要依賴檢測潛在攻擊可能引發的異常控制流來實現。由于智能合約運行在去中心化的環境以及在高度受限的環境中運行,現有的IDS技術或者工具等以外部攔截形式的部署架構不適合于以太坊智能合約。為了解決這些問題,通過設計一個嵌入式的架構,實現了把ContractGuard直接嵌入智能合約的執行代碼中,作為智能合約的一部分。在運行時刻,ContractGuard通過相應的context-tagged無環路徑來實現入侵檢測,從而保護智能合約。由于嵌入了額外的代碼,Contract Guard一定程度上會增加智能合約的部署開銷與運行開銷,為了降低這兩方面的開銷,基于以太坊智能合約的特性對ContractGuard進行優化。實驗結果顯示,可有效地檢測83%的異常行為,其部署開銷僅增加了36.14%,運行開銷僅增加了28.17%。 Ethereum smart contracts are programs that can be collectively executed by a network of mutually untrusted nodes. Smart contracts handle and transfer assets of values, offering strong incentives for malicious attacks. Intrusion attacks are a popular type of malicious attacks. ContractGuard, the first intrusion detection system (IDS) was proposed to defend Ethereum smart contracts against such attacks. Like IDSs for conventional programs, ContractGuard detects intrusion attempts as abnormal control flow. However, existing IDS techniques or tools are inapplicable to Ethereum smart contracts due to Ethereum’s decentralized nature and its highly restrictive execution environment. To address these issues, ContractGuard was designed by embedding it in the contracts. At runtime, ContractGuard protects the smart contract by monitoring the context-tagged acyclic path of the smart contract. As ContractGuard involves deployment overhead and deployment overhead. It was optimized under the Ethereum Gas-oriented performance model to reduce the overheads. The experimental results show that this work can effectively detect 83% of vulnerabilities, ContractGuard only adds to 36.14% of the deployment overhead and 28.27% of the runtime overhead. © 2020, Beijing Xintong Media Co., Ltd.. All rights reserved

粪便颗粒大小对大熊猫类固醇激素测定的影响

利用不同孔径筛网对真空冷冻干燥后的大熊猫（Ailuropoda melanoleuca）粪便进行筛取以量化粪便颗粒大小，采用酶联免疫吸附法（ELISA）测定粪便类固醇激素，探究粪便颗粒大小与激素含量的相关性。结果显示：筛网孔径在3个指标下（雌酮-3-葡糖苷酸、孕酮和皮质醇）均存在主效应，且激素含量大致呈现出随筛网孔径增加而减小的特点。3.35 mm（6目）与1.70 mm（10目）孔径筛网筛选的筛下物激素含量整体表现出最低水平，0.88 mm（18目）的激素含量居中，0.43 mm（35目）、0.23 mm（65目）和0.12 mm（120目）的整体水平最高，这3个激素水平组间均存在显著差异性（P<0.05）。此外，由于0.43、0.23、0.12 mm之间激素含量差异不显著，同时考虑到实操性，0.43 mm筛网是较为合适的选择。分别在粪便取样试管的上部、中部与下部取样测量，显示激素含量存在不同程度的差异，表明粪样的充分混合是必要的。本研究提供了一种适用于大熊猫粪便类固醇监测的冻干研筛法和一种可供参考的混样方法，为大熊猫粪便类固醇激素研究提供方法借鉴，以期为野生大熊猫内分泌研究提供技术指导，也为今后大熊猫非损伤性取样研究提供有价值的参考

大熊猫粪便皮质醇激素分布与取样对策

粪便皮质醇激素对衡量动物应激强度具有较好的指示作用,但其检测准确性受诸多因素影响。为了评估不同取样方式对大熊猫(Ailuropoda melanoleuca)粪便皮质醇测定产生的影响,将粪便横向纵向四等分分割,采用冻干研筛法与酶联免疫吸附法(ELISA)处理每部分粪便和测定激素含量,旨在分析粪便激素分布情况以进一步探讨取样对策。结果显示:每部分粪便的皮质醇含量无显著差异(df=3,F=0.033,P=0.992),粪便在四等分处理下的激素分布比较均匀,即每部分粪便激素均能在一定程度上代表整体水平。1/2取样所产生的变异系数小于1/4取样,前者的检测准确性更高。粪便湿重与尺寸大小存在显著正相关性(r=0.897,Py=2.3x-29.3(y为粪便湿重,x为粪便大小,R2=0.804,F=418.846,P<0.001)。粪便干重由粪便类型、尺寸和含水率决定。在野外工作中,建议采用纵向1/2的取样对策

不同产地美藤果籽的物性比较 Comparison of physical properties of sacha inchi seeds from different areas

为了给美藤果的开发利用提供参考数据，采集了中国云南省普洱、西双版纳、红河，老挝4个产地的美藤果籽，对其感官特性、理化特性及营养特性进行分析比较。结果表明：美藤果籽为类椭圆形，色泽呈浅褐色至深褐色，具有美藤果特有的植物香气；4个产地的美藤果籽单粒厚度为6.8～11.28 mm，粒径为15.81～24.83 mm，单粒质量为0.82～1.53 g，壳仁比为0.52∶ 1～0.78∶ 1，水分含量为7.21%～7.90%；美藤果籽粗脂肪含量为44.98%～50.25%，粗蛋白质含量为27.65%～3028%，总糖含量为3.05%～3.21%，灰分含量为2.28%～2.63%；美藤果籽中维生素E含量为122～190 mg/100 g，钙含量为60.2～63.8 mg/100 g，磷含量为517～535 mg/100 g，钾含量为108～112 mg/100 g，必需氨基酸总量为10.07～10.68 g/100 g，氨基酸总量为31.55～32.82 g/100 g；4个产地的美藤果籽油中棕榈酸含量为3.82%～4.62%，硬脂酸含量为1.87%～3.87%，油酸含量为711%～11.09%，亚油酸含量为37.30%～38.58%，亚麻酸含量为40.78%～48.40%。总体来说，不同产地的美藤果籽感官特性、理化特性及营养特性差异较大，相比较而言，中国普洱产地的美藤果籽在物性指标方面表现更为突出，可作为美藤果油和美藤果蛋白原料的选择。In order to provide reference data for the development and utilization of sacha inchi, the sensory, physicochemical and nutritional properties of the sacha inchi seeds from different areas (Pu’er, Xishuangbanna, Honghe in Yunnan Province, China, and Laos )were analyzed. The results showed that the sacha inchi seeds were oval in shape, light brown to dark brown in color, and had the unique plant aroma of sacha inchi. The single grain thickness of sacha inchi seeds from the four origins was 6.8-1128 mm, grain diameter was 15.81-24.83 mm, single grain mass was 0.82-1.53 g, ratio of shell to kernel was 0.52∶ 1-0.78∶ 1, and moisture content was 7.21%- 7.90%. The contents of crude fat, crude protein, total sugar and ash were 44.98%-50.25%, 27.65%-30.28%, 3.05%-3.21%, 2.28%-2.63%, respectively. The contents of vitamin E, calcium, phosphorus, potassium, total essential amino acids and total amino acids in the sacha inchi seeds were 122-190 mg/100 g, 602-63.8 mg/100 g, 517-535 mg/100 g, 108-112 mg/100 g, 10.07-10.68 g/100 g, 31.55-32.82 g/100 g, respectively. In the seed oil, the contents of palmitic acid, stearic acid, oleic acid, linoleic acid and linolenic acid were 382%-4.62%, 1.87%-3.87%, 7.11%-11.09%, 37.30%-38.58% and 40.78%-48.40%, respectively. In general, the sensory, physicochemical and nutritional properties of the seeds from different regions varied significantly. In comparison, the seeds from Pu’er of China showed more outstanding performance in terms of physical properties and could be used as a raw material for sacha inchi seed oil and sacha inchi seed protein

高重频调制多脉冲YAG激光刻花系统及加工方法

本发明的YAG激光刻花设备具有声光调Q的YAG激光器，在微机控制下输出轻调Q的高频编组脉冲，激光经聚焦头聚焦于工件表面，聚焦头和工件分别在微机控制下沿互相垂直的轨道移动，以使激光在工件上加工出所需图形，采用辅助气体斜角侧吹和偏心或华侨加工方式，在冷轧辊的毛化和刻花工艺中具有突出的效果

Prediction of Energy Resolution in the JUNO Experiment

International audienceThis paper presents the energy resolution study in the JUNO experiment, incorporating the latest knowledge acquired during the detector construction phase. The determination of neutrino mass ordering in JUNO requires an exceptional energy resolution better than 3% at 1 MeV. To achieve this ambitious goal, significant efforts have been undertaken in the design and production of the key components of the JUNO detector. Various factors affecting the detection of inverse beta decay signals have an impact on the energy resolution, extending beyond the statistical fluctuations of the detected number of photons, such as the properties of liquid scintillator, performance of photomultiplier tubes, and the energy reconstruction algorithm. To account for these effects, a full JUNO simulation and reconstruction approach is employed. This enables the modeling of all relevant effects and the evaluation of associated inputs to accurately estimate the energy resolution. The study reveals an energy resolution of 2.95% at 1 MeV. Furthermore, the study assesses the contribution of major effects to the overall energy resolution budget. This analysis serves as a reference for interpreting future measurements of energy resolution during JUNO data taking. Moreover, it provides a guideline in comprehending the energy resolution characteristics of liquid scintillator-based detectors