First report on Guanshan Biota(Cambrian Stage 4) at the stratotype area of Wulongqing Formation in Malong County, Eastern Yunnan, China

Exceptionally preserved fossils,such as those from Cambrian Burgess Shale-type fossil-Lagerstatten are critical because of their unique contributions to knowledge of the phylogenetic radiation and palaeoecological expansion of metazoans during the Cambrian explosion.Critically,these deposits provide information that is usually unobtainable from shelly and skeletonized fossils alone.The Guanshan Biota(Cambrian Series 2,Stage 4)in the Yunnan Province of South China,has produced abundant and diverse,exquisitely preserved fossils that often retain soft tissues and organs.To date,most fossils from the Guanshan Biota have been collected from localities such as Gaoloufang and Gangtoucun,which have become inaccessible due to new urban expansions and constructions of residential buildings.Here we present the first report of soft bodied fossils from a new section at Kanfuqing,close to the Wulongqing village in Malong County,approximately 3 km east of the Wulongqing Formation stratotype section.Fossils retain soft morphology,and include brachiopods with delicate marginal setae,priapulids with well-preserved sclerites and vetulicolians with entire sections of body.In addition,this fauna includes rare occurrences of trilobites preserved with soft tissues replicated as pyrite pseudomorphs after weathering.This discovery represents an important palaeogeographical extension of soft-bodied fossils of the Guanshan fauna to the east of the Xiaojiang Fault(related to Tsinning tectonic movements ca.700 Ma).The fauna from the new Kanfuqing section is similar to that reported from the Wulongqing Formation west of the Xiaojiang Fault,and thus has significant implications for early Cambrian palaeogeography,faunal successions and palaeoenvironments of eastern Yunnan.

Hydrodynamic cavitation as an efficient method for the formation of sub-100 nm O/W emulsions with high stability

Hydrodynamic cavitation,a newly developed process intensification technique,has demonstrated immense potential for intensifying diverse physical and chemical processes.In this study,hydrodynamic cavitation was explored as an efficient method for the formation of sub-100 nm oil-in-water(O/W) emulsions with high stability.O/W emulsion with an average droplet size of 27 nm was successfully prepared.The average droplet size of O/W emulsions decreased with the increase of the inlet pressure,number of cavitation passes and surfactant concentration.The formed emulsion exhibited admirable physical stability during 8 months.Moreover,the hydrodynamic cavitation method can be generalized to fabricate large varieties of O/W emulsions,which showed great potential for large-scale formation of O/W emulsions with lower energy consumption.

Effect of Variable Blank Holder Force on Rectangular Box Drawing Process of Hot-galvanized Sheet Steel

At first, a series of finite element method （FEM） simulation tests were used to find the critical forming conditions of hot-galvanized sheet steel during the rectangular box drawing processing when constant blank holder forces were applied. According the test results, the reasonable alteration scope of initial variable blank holder force （VBHF） was as 1.9-2.3 T. Then, based on the test productions of blank holder force, 12 typical VBHF curves were applied to perform the simulation tests by the simulation software of DYNAFORM. The simulation test results showed that VBHF had great effects on drawing formability of hot-galvanized sheet steel during the rectangular box drawing. However, the different VBHF curves were applied to control the whole drawing and it would get great different effects. At the same tine, the VBHF had great effects on the maximum thick thinning ratio, but had little effect on the maximum thick incrassation ratio. So, reasonable application of the VBHF would greatly decrease the fractures. When the VBHF profile is taken as curve L, the best effect of drawing formability could be obtained. When curve I is used, contrary effect could be gotten. The other types of curves would cause effects between above two types of VBHF curves. Finally, the actual tests were applied to check the validity of the FEM simulation tests. The results show that the FEM simulation tests are good ways for predicting and optimizing the VBHF.

Paleoclimatic and provenance implications of magnetic parameters from the Miocene sediments in the Subei Basin

Thick sediments from foreland basins usually provide valuable information for understanding the relationships between mountain building,rock denudation,and sediment deposition.In this paper,we report environmental magnetic measurements performed on the Miocene sediments in the Subei Basin,northeastern Tibetan Plateau.Our results show two different patterns.First,the bulk susceptibility and SIRM,ARM,and HIRM mainly reflect the absolute-concentration of magnetic minerals;all have increased remarkably since 13.7 Ma,related to provenance change rather than climate change.Second,the ratios of IRM100mT/SIRM,IRM100mT/IRM30mT,and IRM100mT/IRM60mT,together with the redness and S ratio,reflect the relative-concentration of hematite,being climate-dependent.Their vertical changes correlate in general with the long-term Miocene climatic records of marine oxygen isotope variations,marked by the existence of higher ratios between 17 and 14 Ma.This may imply that global climate change,rather than uplift of the Tibetan Plateau,played a dominant role in the long-term climatic evolution of the Subei area from the early to middle Miocene.

Effect of Friction on the Drawing Process of Hot-Galvanized Sheet Steel

A probe test method was employed to detect the friction condition of the interfaces between tools and blank. At the same time a self-developed measurement apparatus to realize the probe test method was also presented. Based on the analysis of force, a correlative friction model was also given. With the self-developed measurement apparatus,the effects of three kinds of lubricating oils which were in common use during the process of sheet steel drawing were studied. By probing the friction coefficient values of different lubricating oils during the drawing process of the hot-galvanized sheet steel （steel brand： ST07Zn）, we can see that the friction caused by PK oil was the lowest, so the effect of PK oil was the best. Then PK oil was used as the base lubricating oil and some solid additive powers was added into it to make a new type lubrication （named as L oil）.The result of test proved that the new lubricating oil had remarkable effect on the drawing process of hot-galvanized sheet steel.

Three-stage Nonlinear Thermal Model for Microspeakers in Mobile Phones

Since microspeakers are widely used in mobile phones,high power is usually applied to obtain sufficient output sound pressure.However,the electric power is almost converted into heat,leading to the thermal problem in microspeakers.Compared with large loudspeaker,microspeakers are smaller and the under yoke is relatively closed,causing the heat transfer more complex.In this study,a three-stage nonlinear thermal model was proposed for analyzing the thermal behavior in microspeakers.The inside air is a buffer area between the voice coil and magnet,and modeled as a middle stage of the heat transfer.The forced convection is still significant in microspeakers while the eddy current can be ignored.In order to obtain the thermal parameters of the model,a corresponding parameter identification method was put forward.The basic linear parameters and forced convection parameters were all obtained by measuring and fitting the temperature curves of voice coil at different single tones.A series of experiments were conducted to verify the proposed model and parameter identification method,and the results showed good aggrement between the measured and predicted temperature curves for different input signals.The proposed model was valid and accurate,and may be helpful for the design and application of microspeakers.

揭示鱼鳞降低冰黏附力的奥秘

近几十年来,大量的研究文献表明,研究人员一直在探究静态表面特性(包括自由能、韧性和弹性)对疏冰性的影响.然而,对于动态表面特性在辅助除冰方面的理解非常有限.在本工作中,我们重点研究了北三文鱼表皮的冰黏附强度,并且观察到了有趣的各向异性的冰黏附行为.与顺着鱼鳞生长方向的冰黏附强度(353±95 kPa)相比,逆着鱼鳞生长方向的冰黏附强度(141±47 kPa)降低了60%.我们发现,鱼鳞在受到剪切力的过程中,会发生独特的结构演变,从而导致界面连续断裂,有利于降低冰的黏附性.研究发现,鱼鳞的张开和剥离能力(描述了鳞片在外力下与其下部鳞片和黏结物分离的趋势)可以调控冰的脱落.通过提高鱼鳞的张开和剥离能力,可以在鱼鳞上实现更低的冰黏附强度(66±15 kPa)和更为容易的除冰过程.由于鱼鳞具有出色的机械鲁棒性,这一发现为设计坚硬耐用的防覆冰表面提供了新的视角.

A Non-Halogenated Polymer Donor Based on Imide Unit for Organic Solar Cells with Efficiency Nearly 16%

Comprehensive Summary,Non-halogenated polymers have great potential in the commercialization of organic solar cells(OSCs)due to their advantages in the manufacturing process.However,high-performance donor polymers are limited to a small amount of building blocks.Herein,we utilize as building block 4H-dithieno[3,2-e:2',3'-g]isoindole-4,6(5H)-dione(DTID)to design and synthesize a relevant non-halogenated polymer PBTID for active layers in OSCs.PBTID exhibits a strong absorption in the wavelength range of 400—600 nm with a distinctly wide optical bandgap of 2.06 eV,a low-lying highest occupied molecular orbital(HOMO)energy level of−5.53 eV.In addition,this polymer has a very strong aggregation effect in solution and could form nanoscale fibrils in the neat film.Consequently,when blended with the non-fullerene acceptor Y6,the devices achieve a prominent PCE of 15.8%with a high Voc of 0.87 V.The Voc and PCE values are one of the highest values in the non-halogenated polymer donor-based OSCs reported to date.

An asymmetric non-fused electron-deficient building block for low-cost polymer acceptor in all-polymer solar cells

The development of polymerized fused-ring small molecule acceptors(FRA-PAs) has boosted the performance of all-polymer solar cells(all-PSCs).However,these FRA-PAs suffer from lengthy synthesis steps and high production costs due to the high degree of synthetic complexity for fused-ring small molecule acceptors(FRAs).Furthermore,most FRA-PAs exhibit strong batch-to-batch variation,limiting further industrial applications.Herein,we designed and synthesized asymmetric non-fused electron-deficient building block TIC-Br with a simple structure(only three synthetic steps),showing a planar configuration,excellent electron affinity,and large dipole moment.A simple polymer acceptor PTIB was further developed by polymerization of TIC-Br and sensitized fluorinated-thienyl benzodithiophene(BDT-TF-Sn).PTIB exhibits a broad absorption from 300 to 800 nm,a suitable lowest unoccupied molecular orbital(LUMO) energy level of-3.86 e V,and moderate electron mobility(1.02×10^(-4)cm^(2)V^(-1)s^(-1)).When matched with PM6,the device achieved the best PCE of 10.11%with a high V_(OC) of 0.97 V,which is one of the highest among those reported all-PSCs.More importantly,PTIB exhibits a lower synthetic complexity index(SC=35.0%)and higher figure-of-merit values(FOM=29.0%) than all the reported high-performance PAs.The polymer also exhibits excellent batch-to-batch reproducibility and great potential for scale-up fabrication.This study indicates that TIC-Br is a promising building block for constructing low-cost polymer acceptors for large-scale applications in all-PSCs.

Unified Analysis and Output Estimation for a Strong Coupling Contactless Slipring System

A contactless slipring (CS) system utilizing inductive-power-transfer (IPT) technology is a good candidate for traditional mechanical slipring assemblies. However, suffering from the high harmonic currents in strong coupling CS systems, the output power will deviate from the theoretical values estimated by the fundamental harmonic approximation (FHA) and its extension method, i.e., E-FHA, in which the power is transferred by both the fundamental current and the high order harmonic currents. In order to achieve high precise output estimation, a unified analysis is proposed in this paper. First, “Fundamental-harmonic Double Resonance Phenomenon” is revealed via impedance analysis, to address the nature of the high harmonic currents in strong coupling systems. Then, a unified output current expression owning high precision is derived, and followed by a unified fundamental load impedance. Discussions show that both the output and the fundamental load impedance of FHA, and E-FHA are the special cases of the unified expressions proposed. FHA and E-FHA are precise enough for the loose coupling system, whereas the proposed method is indispensable for the strong coupling system with k>0.4 . Finally, simulations and experimental measurements of a 1.6kW CS system, as well as the comparative studies related to FHA, E-FHA, and the proposed method, are presented, indicating that the proposed method is effective for high precise output estimation.

油气工况下提升管出口旋流快分系统性能的数值研究

为促进旋流快分(SVQS)系统的工业应用、准确评估其性能,参照国家标准设计了一系列不同密度、黏度的油气模型,并采用商用软件FLUENT 2019 R3对一套Φ600 mm×3150 mm的SVQS系统进行了流动模拟和可行性验证。用单因素变量法分别研究了油气性质对系统无量纲切向速度和压降的影响;用标量输运方程分析了油气在系统内的停留时间分布规律。结果表明,无量纲切向速度随油气密度增加或黏度降低而变大;无量纲最大切向速度随油气密度增加或黏度减小而呈对数递增,最大为0.912;密度越大、黏度越小的油气在SVQS系统内的平均停留时间越短,最短可达6.279 s;压降、阻力系数不仅与系统的结构参数相关,也与油气黏度呈对数关系。拟合得到了与油气参数相关的无量纲切向速度、压降和阻力系数函数式,具有较好的普适性,可为SVQS系统的结构优化提供参考。

不同油气参数下SVQS系统内颗粒浓度场的模拟

为研究提升管出口旋流快分(SVQS)系统中催化剂颗粒的运动规律与浓度分布特征,对不同油气参数下SVQS系统的气固分离进行了数值流动模拟,从粒径、浓度分布和颗粒返混三个方面进行了分析。结果表明,在入口浓度一定的情况下,油气密度越大或黏度越小,封闭罩壁面处颗粒浓度越大,呈螺旋状分布的细带带宽和螺距不同;在隔流筒盖板处有颗粒大量聚集,并形成具有周期脱落特点的颗粒环带;隔流筒底部出现的“短路流”现象,削弱了SVQS系统的分离性能;不同粒径的颗粒下行时始终处于螺旋分层排列状态,且SVQS系统对直径为0.013 mm以下的细小颗粒的分离性能较弱。油气密度越大或黏度越小,颗粒间的跟随性更佳,浓度分布更均匀,SVQS系统对中、细颗粒的捕捉能力变强。SVQS系统中存在颗粒返混现象,且随油气密度增大或黏度减小而削弱。削弱颗粒返混、抑制颗粒高峰是提高该系统分离性能的重要方式。

Numerical investigation of a novel pattern for reducing residual stress in metal additive manufacturing

Deposition patterns can significantly affect residual stress distribution in additive manufacturing processes.In this paper,a novel pattern,the S-pattern,is proposed for the metal additive manufacturing process.The finite element method is used to study the temperature field and the stress field of a cuboid structure under the S-pattern and five other representative patterns:zig-zag,raster,alternate-line,in-out spiral,and out-in spiral.The results show that the S-pattern achieves the lowest values of both equivalent residual stress and maximum principal residual stress,and the warpage of the S-pattern is close to that of counterparts.By analyzing the temperature and stress fields under all patterns,it is found that the residual stress distribution is determined by the uniformity of temperature distribution which is correlated with the peak temperatures of corners.The equivalent residual stress and the maximum principal residual stress are inversely correlated with the average peak temperature and the minimum peak temperature of corners,respectively.These correlations between temperature and residual stress provide an effective approach to evaluate the residual stress of different patterns and guide the deposition process in practice.

The Interpretation of Seismogenic Fault of the Maduo Mw 7.3Earthquake,Qinghai Based on Remote Sensing Images——A Branch of the East Kunlun Fault System

On May 22,2021,a Mw 7.3 earthquake occurred in Maduo County,Qinghai Province with the epicenter of 34.59°N,98.34°E.The distribution of aftershocks and surface ruptures suggested that the seismogenic structure might be the Jiangcuo fault(JF),~70 km south of East Kunlun fault(EKLF).Due to the high altitude and sparse human habitats,there are very few researches on the Jiangcuo fault,which makes us know little about the deformation features and even the geometry of Jiangcuo fault.In this study,we used the high-resolution pre-earthquake satellite images to interpret the spatial distribution and geometry of the Jiangcuo fault.Our results show that the Jiangcuo fault strikes nearly east,extending 180-km-long from Eling Lake to east of Changmahe Town.Based on the geometric features,the Jiangcuo fault could be divided into three segments characterized as the linear structures,fault valleys,scarps and systematic offset of channels.The boundary between Bayan Har Block and Qaidam Block is presented as a wide deformation zone named of Kunlun belt that is composed of East Kunlun fault and several branch faults around Anemaqen Mountain.Geometric analysis and deep lithosphere structure around Maduo County suggest that the Jiangcuo fault should be one of branch of East Kunlun fault at south,where the Kunlun fault developed as a giant flower structure.In addition,the seismic hazards potential of Jiangcuo fault should be given enough attention in the future,because west of the Jiangcuo fault,there is a rupture gap between the co-seismic surface ruptures of the 2001 Kunlun,2021 Maduo and 1937 Huashixia Earthquakes.

Comparison of Wide-bandgap Devices in 1 kV,3 kW LLC Converters

Emerging wide-bandgap(WBG)devices,such as silicon carbide(SiC)MOSFETs and gallium nitride(GaN)high-electron-mobility transistors(HEMTs)provide new opportunities to realize high efficiency,high power density,and high reliability in several kHz,1 kV input,and several kW output applications.However,the performance comparison between SiC MOSFETs and GaN HEMTs in high-voltage,high-frequency,medium-high-power DC conversion applications have not yet been investigated thoroughly.Two 1 kV,3 kW LLC prototypes with GaN and SiC devices are built to perform a careful comparison of the prototypes in terms of parameters,power density,zero voltage switch realization,and overall efficiency.This provides guidance for the appropriate evaluation of WBG devices in high-voltage,high-frequency,and medium-high-power applications.

Irbesartan drug formulated as nanocomposite particles for the enhancement of the dissolution rate

Irbesartan （IBS）, an angiotensin II receptor antagonist, is a poorly water-soluble drug. To enhance the dis- solution rate, IBS nanocomposite particles were produced via an anti-solvent precipitation combined with a spray drying process. Four pharmaceutically acceptable excipients, including three different polymers and one charged surfactant, were evaluated as stabilizers to control the particle size and to prevent the agglomeration of particles. The experiment results indicated that polyvinylpyrrolidone （PVP） combined with sodium dodecyl sulfate （SDS） significantly decreased the particle size and enhanced the stability of drug nanoparticles. As a result, we finally obtained stable IBS nanoparticles with an average size of approx- imately 55 nm. In the dissolution test, the IBS nanocomposite particles showed a significantly enhanced dissolution rate and 100% of the drug dissolved within 20 rain. In contrast, the physical mixture with the same recipe as the IBS nanocomposite particles and the raw 1BS reached only 8% and 40% of drug dissolved in 20 rain, respectively, and both of them did not dissolve completely, even after 120 rain.

Influence of welding residual stresses on the ductile crack growth resistance of circumferentially cracked pipe

Welding residual stress is one of the main concems for fabrication and operation of steel structures due to its potential effect on structural integrity.This paper focuses on the effect of welding residual stress on the ductile crack growth resistance of circumferentially cracked steel pipes.Two-dimensional axi-symmetry model has been used to simulate the pipe.Residual stresses were introduced into the model by using so-called eigenstrain method.The complete Gurson model has been employed to calculate the ductile crack growth resistance.Results show that residual stresses reduce the ductile crack growth resistance.However,the effect of residual stresses on ductile crack growth resistance decreases with the increase of crack growth.The effect of residual stress has also been investigated for cases with different initial void volume fraction,material hardening and crack sizes.

Modeling nanoscale ice adhesion

Anti-icing is crucial for numerous instruments and devices in low temperature circum- stance. One of the approaches in anti-icing is to reduce ice adhesion strength, seeking spontaneous de-icing processes by natural forces of gravity or by winds. In order to enable tai- lored surface icephobicity design, research requires a good theoretical understanding of the atomistic interacting mechanisms between water/ice molecules and their adhering substrates. Herein, this work focuses on using atomistic modeling and molecular dynamics simulation to build a nanosized ice-cube adhering onto silicon surface, with different contact modes of solid-solid and solid-liquid-solid patterns. This study provides atomistic models for probing nanoscale ice adhesion mechanics and theoretical platforms for explaining experimental results.