UPLC-MS metabolomics provides insights into the diff erences between black- and white-shelled Pacifi c oysters Crassostrea gigas

A variety of shell colors are one of the most fundamental characteristics of molluscs,which have importantly ecological and economic signifi cance.The Pacifi c oyster Crassostrea gigas is distributed in many sea areas around the world and also an aquacultured mollusc with high nutritional value.In this study,the whole soft body and the mantle tissue of black-shelled Pacifi c oyster(BSO)and white-shelled Pacifi c oyster(WSO)with starkly diff erent melanin contents were compared,and the diff erences in physiology and metabolism between BSO and WSO were analyzed.The results of physiological indicators suggested BSO show more melanin,more dry matter,more crude lipid content,and stronger ability to scavenge free radicals than WSO.The altered metabolites of glycerophospholipids,fatty acyls,and steroids revealed diff erent regulatory mechanisms of lipids.The correlation analysis of metabolomics and previously published RNAseq data suggested that BSO and WSO mainly diff ered in the basal metabolic processes,such as lipid,amino acid and purine metabolisms.This study provides insights into the changes in the physiological indictors and the metabolites of oysters with varying melanin content.

Electrochemical behavior of different shelled microcapsule composite copper coatings

Copper/liquid microcapsule composite coatings with polyvinyl alcohol （PVA）, gelatin or methyl cellulose （MC） as shell materials were prepared by electrodeposition. The influence of shell materials on the corrosion resistance of the composite coatings in 0.1 M H2SO4 was investigated by means of electrochemical techniques, scanning electron microscopy （SEM）, and energy dispersion spectrometry （EDS）. The results show that the participation of microcapsules can enhance the corrosion resistance of the composite coatings compared with the traditional copper layer. Based on the analysis of electrochemical test results, the release ways of microcapsules were deduced. Gelatin and MC as the shell materials of microcapsules are easy to release quickly in the composite coating. On the contrary, the releasing speed of PVA microcapsules is relatively slow due to their characteristics.

Northern Blot and Immunohistochemistry Analysis of HMOX1Expression in Blue- and Brown-shelled Chickens

HMOX1 is an important functional candidate gene for chicken blue egg in view of its role in biosynthesis of biliverdin for blue egg coloration. To elucidate molecular mechanism of blue egg formation, this study detected expression of HMOX1 in blue-shelled chickens and brown-shelled chickens. Expression and alternative splicing of HMOX1 were detected by Northern blot, expression traits of HO-1 protein in shell glands of blue- （n=4） and brown-shelled （n=4） chickens were analyzed by immunohistochemistry. 3＇ UTR of HMOX1 was cloned using 3＇RACE. Results showed that the expression of HMOX1 at mRNA level had no significant difference between two groups of chickens, but at protein level HO-1 protein was highly expressed in blue-shelled chickens. Immunohistochemistry analysis showed that HO-1 protein expression was predominately located in villus epithelial cell of shell gland. Length of HMOX1 3＇ UTR were 586 bp. In 3＇ UTR we found a SNP of rs13866562 showing significant association with blue egg phenotype. Further miRNA prediction showed that it might influence interaction of some miRNAs and target sequences. The data suggested that blue egg is relevant to high expression of HO-1 in villus epithelial cell of shell gland. Further experimental validation for biological relevance of miRNAs is dispensable to elucidate reason for differential expressions of HO-1 protein.

基于SHELL模型的航空货物运输安全问题研究

文章阐述了SHELL 模型的基本理论,分析了航空货物运输的基本流程及常见安全问题,应用SHELL模型重点探究航空货物运输中人与硬件(L-H)、人与软件(L-S)、人与环境(L-E)及人与人(L-L)的要素特征与关系界面,梳理引发安全问题导致不安全事件的原因,提出缩小关系界面空隙、提高关系匹配度的措施,保障航空货物运输安全,促进航空货运持续稳定发展。

基于文本分析的飞机牵引车作业不安全事件研究

为了研究飞机牵引车作业过程的安全性,文章对1989年至2023年间自愿报告系统(ASRS)中12537条涉及飞机牵引车作业不安全事件的叙述和简述部分进行了文本挖掘和文本分析,并结合SHELL模型识别了飞机牵引车作业关键要素,最后采用SHEL-Jaccard系数矩阵对关键要素之间的关系进行分析,提出飞机牵引车作业安全预防和控制措施。研究发现,飞机牵引车作业关键要素如下:以销、刹车、速度控制装置、连接装置、通讯设备为主的硬件要素;以牵引车检查单、机场地面引导线、机场管理为主的软件要素;以牵引车司机、引导、警戒和机组为主的主要人员和以能见度、地面状况、障碍物为主的环境要素。

基于Shell脚本的KVM虚拟化技术应用

虚拟化技术是当前计算机信息技术中一个新的变革,其中开源的虚拟化技术(Kernel-Based Virtual Machines,KVM)更是以稳定、高效、经济而著称,为科学研究、工程仿真等领域提供了强大的计算能力。文章以某高职院校虚拟化应用为实例,探讨在普通高职院校的虚拟化技术应用管理中使用Shell脚本进行智能化管理,并展示其技术用于云平台辅助管理的优势,为用户轻便智能管理KVM虚拟化技术应用提供参考。

Snap-through behaviors and nonlinear vibrations of a bistable composite laminated cantilever shell:an experimental and numerical study

The snap-through behaviors and nonlinear vibrations are investigated for a bistable composite laminated cantilever shell subjected to transversal foundation excitation based on experimental and theoretical approaches.An improved experimental specimen is designed in order to satisfy the cantilever support boundary condition,which is composed of an asymmetric region and a symmetric region.The symmetric region of the experimental specimen is entirely clamped,which is rigidly connected to an electromagnetic shaker,while the asymmetric region remains free of constraint.Different motion paths are realized for the bistable cantilever shell by changing the input signal levels of the electromagnetic shaker,and the displacement responses of the shell are collected by the laser displacement sensors.The numerical simulation is conducted based on the established theoretical model of the bistable composite laminated cantilever shell,and an off-axis three-dimensional dynamic snap-through domain is obtained.The numerical solutions are in good agreement with the experimental results.The nonlinear stiffness characteristics,dynamic snap-through domain,and chaos and bifurcation behaviors of the shell are quantitatively analyzed.Due to the asymmetry of the boundary condition and the shell,the upper stable-state of the shell exhibits an obvious soft spring stiffness characteristic,and the lower stable-state shows a linear stiffness characteristic of the shell.

Mechanical Performance of Bio-inspired Bidirectional Corrugated Sandwich Pressure Shell Under External Hydrostatic Pressure

This paper aims to enhance the compression capacity of underwater cylindrical shells by adopting the corrugated sandwich structure of cuttlebone.The cuttlebone suffers uniaxial external compression,while underwater cylindrical shells are in a biaxial compressive stress state.To suit the biaxial compressive stress state,a novel bidirectional corrugated sandwich structure is proposed to improve the bearing capacity of cylindrical shells.The static and buckling analysis for the sandwich shell and the unstiffened cylindrical shell with the same volume-weight ratio are studied by numerical simulation.It is indicated that the proposed sandwich shell can effectively reduce the ratio between circumferential and axial stress from 2 to 1.25 and improve the critical buckling load by about 1.63 times.Numerical simulation shows that optimizing and adjusting the structural parameters could significantly improve the advantage of the sandwich shell.Then,the hydrostatic pressure tests for shell models fabricated by 3D printing are carried out.According to the experimental results,the overall failure position of the sandwich shell is at the center part of the sandwich shell.It has been found the average critical load of the proposed sandwich shell models exceeds two times that of the unstiffened shell models.Hence,the proposed bio-inspired bidirectional corrugated sandwich structure can significantly enhance the pressure resistance capability of cylindrical shells.

Cl/S与Na相互作用对Shell气化炉合成气冷却器入口积灰机制的影响

Shell干粉煤加压气化是煤炭洁净高效利用的重要技术之一,由碱金属化合物引起的合成气冷却器入口积灰结垢是导致气化炉非正常停工检修的主要原因。以添加不同含量的Na、Cl和S的Shell气化炉飞灰为原料,利用自主设计的高温竖直炉中沉积探针模拟Shell气化炉合成气冷却器入口管路,通过对积灰进行内、外分层研究,探讨内外层积灰质量的变化,并结合ICP-MS、IC、SEM-EDS和XRD等表征手段对内外层积灰的理化性质进行比较分析,获得Na、Cl、S和Fe等不同元素之间的相互作用对积灰行为的影响。结果表明,内层积灰质量随时间延长而增大,含S化合物的添加会降低内外层积灰质量,且外层积灰质量会随着时间延长而减小。Na更多以铝硅酸盐形式在外层积灰中存在,促进积灰增长;Cl通常以碱金属氯化物的形式集中在初始黏性层;S的存在会减缓管路积灰;当Cl和S共同存在时,Fe易与灰中的Si、Al和Na形成多种低温共熔物促进内、外层积灰熔融。Shell气化炉合成气冷却器入口积灰形成机制为:飞灰颗粒组分在Na、Cl、Si和Al的共同作用下,于内层形成碱金属氯化物和铝硅酸盐共晶;同时Cl、S的存在促使Fe和Na迁移到这些共晶中,形成Fe-O-Si、Fe-O-S和Fe-Na-O-Al-S共熔体。进而,铝硅酸盐与多种低温共熔体相互熔融使灰颗粒尺寸增加,促进积灰的进一步生长。

Optimizing high-coordination shell of Co-based single-atom catalysts for efficient ORR and zinc-air batteries

Atom-level modulation of the coordination environment for single-atom catalysts(SACs)is considered as an effective strategy for elevating the catalytic performance.For the MNxsite,breaking the symmetrical geometry and charge distribution by introducing relatively weak electronegative atoms into the first/second shell is an efficient way,but it remains challenging for elucidating the underlying mechanism of interaction.Herein,a practical strategy was reported to rationally design single cobalt atoms coordinated with both phosphorus and nitrogen atoms in a hierarchically porous carbon derived from metal-organic frameworks.X-ray absorption spectrum reveals that atomically dispersed Co sites are coordinated with four N atoms in the first shell and varying numbers of P atoms in the second shell(denoted as Co-N/P-C).The prepared catalyst exhibits excellent oxygen reduction reaction(ORR)activity as well as zinc-air battery performance.The introduction of P atoms in the Co-SACs weakens the interaction between Co and N,significantly promoting the adsorption process of ^(*)OOH,resulting in the acceleration of reaction kinetics and reduction of thermodynamic barrier,responsible for the increased intrinsic activity.Our discovery provides insights into an ultimate design of single-atom catalysts with adjustable electrocatalytic activities for efficient electrochemical energy conversion.

Valorization of Camellia oleifera oil processing byproducts to value-added chemicals and biobased materials: A critical review

The C.oleifera oil processing industry generates large amounts of solid wastes,including C.oleifera shell(COS)and C.oleifera cake(COC).Distinct from generally acknowledged lignocellulosic biomass(corn stover,bamboo,birch,etc.),Camellia wastes contain diverse bioactive substances in addition to the abundant lignocellulosic components,and thus,the biorefinery utilization of C.oleifera processing byproducts involves complicated processing technologies.This reviewfirst summarizes various technologies for extracting and converting the main components in C.oleifera oil processing byproducts into value-added chemicals and biobased materials,as well as their potential applications.Microwave,ultrasound,and Soxhlet extractions are compared for the extraction of functional bioactive components(tannin,flavonoid,saponin,etc.),while solvothermal conversion and pyrolysis are discussed for the conversion of lignocellulosic components into value-added chemicals.The application areas of these chemicals according to their properties are introduced in detail,including utilizing antioxidant and anti-in-flammatory properties of the bioactive substances for the specific application,as well as drop-in chemicals for the substitution of unrenewable fossil fuel-derived products.In addition to chemical production,biochar fabricated from COS and its applications in thefields of adsorption,supercapacitor,soil remediation and wood composites are comprehensively reviewed and discussed.Finally,based on the compositions and structural characteristics of C.oleifera byproducts,the development of full-component valorization strategies and the expansion of the appli-cationfields are proposed.

Separation of shelled walnut particles using pneumatic method

Separation of shelled walnut particles was studied on two varieties of Persian walnut,Poost-Kaghazi and Poost-Sangi using pneumatic method.The moisture contents of the samples were determined.The particles were considered in three categories of shell,kernel and shell-kernel together.Each category was manually classified based on their size,in three portions of 1/8,1/4,and 1/2,as well as the whole kernel and whole walnut.The terminal velocity of each group was determined.The shelled walnuts were sieved and classified in three groups of small,medium and large.The effects of separation time(5,10 and 15 seconds),feeding value(50 to 80 gr)and air velocity on separation of the kernels and shells were studied for both varieties.The interaction effects were also studied for three walnut sizes(small,medium and large).The terminal velocity was the highest for the whole walnut and the whole kernel while it was lowest for 1/4 and 1/8 of the shell.The best separation was performed at air velocities of 9.20,10.04 and 10.94 m/s with 98.2%,98.9%and 98.2%,respectively.

Mechanistic investigation on Ag-Cu_(2)O in electrocatalytic CO_(2) to CH_(4) by in situ/operando spectroscopic and theoretical analysis

Silver-copper electrocatalysts have demonstrated effectively catalytic performance in electroreduction CO_(2) toward CH_(4),yet a revealing insight into the reaction pathway and mechanism has remained elusive.Herein,we construct chemically bonded Ag-Cu_(2)O boundaries,in which the complete reduction of Cu_(2)O to Cu has been strongly impeded owing to the presence of surface Ag shell.The interfacial confinement effect helps to maintain Cu^(+)sites at the Ag-Cu_(2)O boundaries.Using in situ/operando spectroscopy and theoretical simulations,it is revealed that CO_(2) is enriched at the Ag-Cu_(2)O boundaries due to the enhanced physisorption and chemisorption to CO_(2),activating CO_(2) to form the stable intermediate^(*)CO.The boundaries between Ag shell and the Cu_(2)O mediate local^(*)CO coverage and promote^(*)CHO intermediate formation,consequently facilitating CO_(2)-to-CH_(4) conversion.This work not only reveals the structure-activity relationships but also offers insights into the reaction mechanism on Ag-Cu catalysts for efficient electrocatalytic CO_(2) reduction.

Enhancing electromagnetic wave absorption with core‐shell structured SiO_(2)@MXene@MoS_(2) nanospheres

Material composition and structural design are important factors influencing the electromagnetic wave(EMW)absorption performance of materials.To alleviate the impedance mismatch attributed to the high dielectric constant of Ti_(3)C_(2)T_(x)MXene,we have successfully synthesized core‐shell structured SiO_(2)@MXene@MoS_(2)nanospheres.This architecture,comprising SiO_(2) as the core,MXene as the intermediate layer,and MoS_(2) as the outer shell,is achieved through an electrostatic self‐assembly method combined with a hydrothermal process.This complex core‐shell structure not only provides a variety of loss mechanisms that effectively dissipate electromagnetic energy but also prevents self‐aggregation of MXene and MoS_(2) nanosheets.Notably,the synergistic combination of SiO_(2) and MoS_(2) with highly conductive MXene enables the suitable dielectric constant of the composites,ensuring optimal impedance matching.Therefore,the core‐shell structured SiO_(2)@MXene@MoS_(2) nanospheres exhibit excellent EMW absorption performance,featuring a remarkable minimum reflection loss(RL_(min))of−52.11 dB(2.4 mm).It is noteworthy that these nanospheres achieve an ultra‐wide effective absorption bandwidth(EAB)of 6.72 GHz.This work provides a novel approach for designing and synthesizing high‐performance EMW absorbers characterized by“wide bandwidth and strong reflection loss.”

Prediction of shelled shrimp weight by machine vision

The weight of shelled shrimp is an important parameter for grading process.The weight prediction of shelled shrimp by contour area is not accurate enough because of the ignorance of the shrimp thickness.In this paper,a multivariate prediction model containing area,perimeter,length,and width was established.A new calibration algorithm for extracting length of shelled shrimp was proposed,which contains binary image thinning,branch recognition and elimination,and length reconstruction,while its width was calculated during the process of length extracting.The model was further validated with another set of images from 30 shelled shrimps.For a comparison purpose,artificial neural network(ANN) was used for the shrimp weight predication.The ANN model resulted in a better prediction accuracy(with the average relative error at 2.67%),but took a tenfold increase in calculation time compared with the weight-area-perimeter(WAP) model(with the average relative error at 3.02%).We thus conclude that the WAP model is a better method for the prediction of the weight of shelled red shrimp.

基于Python和Shell的《Linux实训项目自测平台》软件设计

近年来,Linux操作系统在各国不断地发展与推广,高等院校开设的Linux操作系统课程也越来越受到重视。通过对软件界面设计及在Linux操作系统中检测实训项目的几种常用方式进行分析和研究,给操作系统课程教学提供一种教学思路,同时对Linux教学辅助软件开发者提供一些借鉴和参考。

粉煤袋式过滤器内粉煤焖烧的原因分析及处理措施

Shell粉煤气化装置在停车检修期间,发生了粉煤袋式过滤器内粉煤焖烧的事故。分析了事故发生的原因,采取停止粉煤外排、输入一定量氮气惰化粉煤袋内的粉煤、间隔洒水降低粉煤温度等措施,避免了粉煤袋式过滤器滤袋和防爆板的损坏。

Dynamics of a rotating ring-stiffened sandwich conical shell with an auxetic honeycomb core

The free vibration analysis of a rotating sandwich conical shell with a reentrant auxetic honeycomb core and homogenous isotropic face layers reinforced with a ring support is studied.The shell is modeled utilizing the first-order shear deformation theory(FSDT)incorporating the relative,centripetal,and Coriolis accelerations alongside the initial hoop tension created by the rotation.The governing equations,compatibility conditions,and boundary conditions are attained using Hamilton’s principle.Utilizing trigonometric functions,an analytical solution is derived in the circumferential direction,and a numerical one is presented in the meridional direction via the differential quadrature method(DQM).The effects of various factors on the critical rotational speeds and forward and backward frequencies of the shell are studied.The present work is the first theoretical work regarding the dynamic analysis of a rotating sandwich conical shell with an auxetic honeycomb core strengthened with a ring support.

透空结构与半潜式风机集成系统耦合运动响应特性分析

A novel semi-submersible platform is proposed for 5 MW wind turbines.This concept focuses on an integrated system formed by combining porous shells with a semi-submersible platform.A coupled aerodynamic–hydrodynamic–mooring analysis of the new system is performed.The motion responses of the novel platform system and the traditional platform are compared.The differences in hydrodynamic performance between the two platforms are also evaluated.The influence of the geometric parameters(porosity,diameter,and wall thickness)of porous shells on the motion response behavior of the new system is studied.Overall,the new semi-submersible platform exhibits superior stability in terms of pitch and heave degrees of freedom,demonstrating minimal effects on the motion response in the surge degree of freedom.

Comparative Transcriptome Analysis of Shell-Matrix-Protein Genes and Observation of the Shell Microstructure in the Deep-Sea Clam Calyptogena marissinica

The deep-sea clam Calyptogena marissinica is widely distributed in the Haima cold seep ecosystem on the northwes-tern slope of the South China Sea with low pH values,low temperature and high pressure.Limited information is available on the biomineralization of this species.In this research,we generated a comprehensive transcript dataset of C.marissinica’s mantle tissue,and a total of 19821 unigenes were assembled.Fourteen shell matrix proteins(SMP)-related genes were identified.The qPCR results showed that four out of six prismatic matrix genes(MSP2,MSP5,prisilkin-39,and shematrin),four out of the six nacreous matrix genes(perlucin,pif,pif97,and papilin),and two extrapallial fluid proteins(SPARC and calmodulin)were significantly expressed in the mantle.Both the nacreous and the prismatic layers are chrysanthemum-shaped,which are stacked on the top of each other to form a laminated nacreous structure.The alignment and phylogenetic analysis of MSP-5,Prisilkin-39,Perlucin,and Pif homologues showed that some amino acids of C.marissinica that differed from those detected in other molluscs may cause the different shape of the nacreous and prismatic layers,but do not lead to a change in the species’evolutionary status.These results indicated the conservation of the functions of SMP-related genes in C.marissinica,and the specific shape of the prismatic and nacreous layers of this deep-sea mollusc,which will contribute to the research on the molecular regulation mechanisms of biomineralization in C.marissinica and provide a new perspective to investigate biomineralization in deep-sea clams in general.