An internal ballistic model of electromagnetic railgun based on PFN coupled with multi-physical field and experimental validation

To accelerate the practicality of electromagnetic railguns,it is necessary to use a combination of threedimensional numerical simulation and experiments to study the mechanism of bore damage.In this paper,a three-dimensional numerical model of the augmented railgun with four parallel unconventional rails is introduced to simulate the internal ballistic process and realize the multi-physics field coupling calculation of the rail gun,and a test experiment of a medium-caliber electromagnetic launcher powered by pulse formation network(PFN)is carried out.Various test methods such as spectrometer,fiber grating and high-speed camera are used to test several parameters such as muzzle initial velocity,transient magnetic field strength and stress-strain of rail.Combining the simulation results and experimental data,the damage condition of the contact surface is analyzed.

聚{(3-乙酰基)吡咯-[2,5-二(对丁氧基苯甲烯)]}的合成与表征

合成了一种新型含有推-拉电子基团的聚吡咯衍生物——聚{(3-乙酰基)吡咯-[2,5-二(对丁氧基苯甲烯)]}(PA-PDBOBE)。通过红外光谱(FT-IR)、核磁共振(^(1)H-NMR)、紫外光谱(UV-Vis)、热重分析(TG)和循环伏安(CV)测试等分析手段对聚合物结构和性能进行了分析。UV-Vis谱表明,PAPDBOBE的光学禁带宽度(E_(g))为1.51 eV。该聚合物的TG谱显示聚合物的热分解温度为165℃。循环伏安特性曲线(CV)表明,该聚合物膜电极在LiClO_(4)乙腈溶液中-1 V~1 V的电压间有氧化还原反应,其氧化还原反应的峰电位分别为0.52 V和-0.51 V。

产业转型期规模猪场建设工程防控技术思考

非洲猪瘟和环保的双重影响刺激了中国养猪业快速向集约化、高效化和自动化方向转型,而舍间交叉感染、疫病难控、环境污染等问题依然未能得到有效解决。在猪场建设和管理中,人们的关注重点主要有疾病控制、粪污臭气治理和无抗饲料三个方面,分别对应着生物安全、环保安全和食品安全三个安全底线。在重视猪场生物安全体系建设时,人们往往忽视工程防控技术措施的整体应用,其贡献尚无法得以很好的体现。文章从工程技术的角度,分析了隔离、合理分区和防止交叉感染等对猪场生物安全防控的作用,为猪场的工程防疫体系建设、守住三个安全底线提供指导。

Numerical study of three-dimensional developments of premixed flame induced by multiple shock waves

The three-dimensional interactions of a perturbed premixed flame interface with a planar incident shock wave and its reflected shock waves are numerically simulated by solving the compressible,reactive Navier-Stokes equations with the high-resolution scheme and a single-step chemical reaction.The effects of the initial incident shock wave strength (Mach number) and the initial perturbation pattern of interface on the interactions are investigated.The distinct properties of perturbation growth on the flame interface during the interactions are presented.Our results show that perturbation growth is mainly attributed to the flame stretching and propagation.The flame stretching is associated with the larger-scale vortical flow due to RichtmyerMeshkov instability while the flame propagation is due to the chemical reaction.The mixing properties of unburned/burned gases on both sides of the flame are quantitatively analyzed by using integral and statistical diagnostics.The results show that the large-scale flow due to the vortical motion always plays a dominating role during the reactive interaction process;however,the effect of chemistry becomes more important at the later stage of the interactions,especially for higher Mach number cases.The scalar dissipation due to the molecular diffusion is always small in the present study and can be negligible.

rSac3, a novel Sac domain phosphoinositide phosphatase, promotes neurite outgrowth in PC12 cells

Sac domain-containing proteins belong to a newly identified family of phosphoinositide phosphatases （the PIPPase family）. Despite well-characterized enzymatic activity, the biological functions of this mammalian Sac domain PIPPase family remain largely unknown. We identified a novel Sac domain-containing protein, rat Sac3 （rSac3）, which is widely expressed in various tissues and localized to the endoplasmic reticulum, Golgi complex and recycling endosomes, rSac3 displays PIPPase activity with PI（3）P, PI（4）P and PI（3,5）P2 as substrates in vitro, and a mutation in the catalytic core of the Sac domain abolishes its enzymatic activity. The expression of rSac3 is upregulated during nerve growth factor （NGF）-stimulated PC 12 cell neuronal differentiation, and overexpression of this protein promotes neurite outgrowth in PC 12 cells. Conversely, inhibition ofrSac3 expression by antisense oligonucleotides reduces neurite outgrowth of NGF- stimulated PC 12 cells, and the active site mutation of rSac3 eliminates its neurite-outgrowth-promoting activity. These results indicate that rSac3 promotes neurite outgrowth in differentiating neurons through its PIPPase activity, suggesting that Sac domain PIPPase proteins may participate in forward membrane trafficking from the endoplasmic reticulum and Golgi complex to the plasma membrane, and may function as regulators of this crucial process of neuronal cell growth and differentiation.

Research on momentum transfer in simple railgun

In this paper,the momentum conservation equation in the longitudinal direction for simple railgun was deduced.Then,a three-dimensional model was established and the finite element method was utilized to simulate the problem.Based on the simulation,some results such as the surface force on the electromagnetic field,the electromagnetic force on the conductor in the longitudinal direction were obtained.Besides,the surface force density on different longitudinal section of railgun was analyzed and discussed in details.The results showed that the momentum of the railgun system was conserved when the surface force of the electromagnetic field was contained.Moreover,large amount of longitudinal force was transmitted to the breech by the electromagnetic field in the form of surface force.The exact position and distribution of recoil were related to the current input device.

Dural sinus septum:an underlying cause of cerebral venous sinus stenting failure and complications

Objectives The presence of dural sinus septum has long been identified anatomically but is often neglected for its clinical significance.Our findings revealed the association of dural sinus septum with venous sinus stenting failure and complications supported by clinical evidence.Methods This retrospective study included 185 consecutive patients treated with cerebral venous sinus stenting from January 2009 to May 2022.We identified the dural sinus septa using digital subtraction angiography(DSA)and classified them into three types based on their location.The septa at the transverse sinus were defined as typeⅠ,those at the junction between the transverse sinus and sigmoid sinus were defined as typeⅡand those at the sigmoid sinus were defined as typeⅢ.Based on the anatomic features and neuroimaging clues,we investigated the correlation of dural sinus septa with stenting failure and complications.Results 32(17.1%)out of 185 patients(121 with idiopathic intracranial hypertension and 64 with venous pulsatile tinnitus)were identified with dural sinus septa by DSA.More than half of the septa were typeⅠ(18/32,56.2%),followed by typeⅡ(11/32,34.4%)and typeⅢ(3/32,9.4%).The dural sinus septa caused three stenting failures and complications,including one case of venous sinus injury with subdural haemorrhage and two cases of incomplete stent expansion.Statistical analysis revealed that the presence of dural sinus septum(p<0.01)was associated with complications of cerebral venous sinus stenting.Discussion The dural sinus septum is a common structure in the cerebral venous sinus.We found that the presence of dural sinus septa introduces uncertainties to cerebral venous sinus stenting and suggested precautions and ingenious skills in imaging and treatment.

Electrolyzed water and its application in animal houses

Electrolyzed water(EW) can be produced by electrolysis of a dilute salt solution. Slightly acidic electrolyzed water(SAEW, p H 5.0–6.5) and neutral electrolyzed water(NEW, p H 6.5–8.5) are considered healthy and environmentally friendly because no hazardous chemicals are added in its production, there is reduced corrosion of surfaces and it minimizes the potential for damage to animal and human health. Over the last decade, EW has become increasingly popular as an alternative disinfectant for decontamination in animal houses. However, there have been some issues related to EW that are not well known, including different mechanisms for generation of SAEW and NEW, and the antimicrobial mechanism of EW. This review covers the definitions of SAEW and NEW, different generation systems for SAEW and NEW, the antimicrobial mechanism of EW, and recent developments related to the application of SAEW and NEW in animal houses.

Impact of global climate change on the health,welfare and productivity of intensively housed livestock

Major scientific studies have shown that global warming(i.e.increasing average temperature of the Earth)is now a reality.The aims of this paper are to broadly review the underlining causes of global warming,the general effects of global warming on social and environmental systems and the specific effects of resulting from global warming phenomena severe fluctuations in weather patterns,particularly heat waves on livestock health,welfare and productivity.Finally this article aims to summarise some common sense climate control methods and more importantly to highlight the required future research and development(R&D)work that is necessary to achieve a new level of building environment control capability,and thus ensure that the intensive livestock industries will be able to cope with the changed external climate.With the increasing temperatures on a global scale,the most direct effect of the high temperature on the animals is heat stress,which has been proven to have a variety of negative effects on animal health,welfare and productivity.Different potential measures could be taken in future to alleviate the increased heat stress.Some of these measures are mere adaptations or improvements of current engineering solutions.However,facing the complex challenges of global warming and particularly resulting from it the rapid increase of the number of consecutive days with significantly higher than average temperatures will probably require novel solutions,including new designs based on solid engineering judgment,development of new engineering standards and codes to guide designs,the exploration of new and superior building materials,the need for better energy management,and the development of substantially more“intelligent”control systems that will balance changing exterior disturbances,interior building loads and demands to the biological needs of the occupants of the structures.

Improving utilization of nests and decreasing mislaid eggs with narrow width of group nests

Provision of nest boxes is necessary for laying hens,especially in non-cage systems.This study investigated the effects of nest width on nest utilization and mislaid eggs.Hy-Line Browns hens were transferred from conventional cages to perchery pens at 12 weeks of age.Two experiments were conducted to mutually verify the hypothesis that narrowing group nests would improve nest utilization and reduce mislaid eggs.In experiment 1,group nests of 150 cm wide in two pens were partitioned at intervals of 50 cm and 37 cm,respectively.In experiment 2,partition panels were removed after acclimation.The number of mislaid eggs and nest eggs in each pre-set section were compared.Results indicated that narrowing group nests had positive effects on improving usage uniformity and efficiency of group nests.Nest eggs were more evenly distributed on the egg belt in both narrowed group nests,which was indicated by the significant decrease of variance among different sections(p<0.001).The proportion of mislaid eggs decreased by 3.5%in 37 cm treatment(p<0.05)and 4.7% in 50 cm treatment(p<0.001),respectively.As expected,reuse of the 150 cm group nests after removal of partition panels lowered the usage uniformity of group nests.A growth of three percentage points was found for the proportion of mislaid eggs after removing the partition panels in 50 cm treatment.The present results indicated that it is the width of the nest box that works for a better use of group nests.In conclusion,adding partition panels at intervals of 50 cm and 37 cm in group nests both are effective on nest usage and decreasing the occurrence of mislaid eggs.

An optimized solar-air degree-day method to evaluate energy demand for poultry buildings in different climate zones

The degree-day method is widely used to determine energy consumption but cannot be directly applied to poultry buildings without improvements in its accuracy.This study was designed to optimize the degreeday calculation and proposes a solar-air degree-day method,which can be used to calculate the cooling and heating degree-days and the annual cooling and heating loads under different climate conditions for poultry buildings.In this paper,the solar-air degree-day method was proposed,which considers the effects of solar radiation with different wall orientations and surface colors.Five Chinese cities,Harbin,Beijing,Chongqing,Kunming and Guangzhou,were selected to represent different climate zones to determine the solar-air degreedays.The heating and cooling energy requirements for different climates were compared by DeST(Designer’s Simulation Toolkit)simulation and the solar-air degreeday method.Approaches to decrease energy consumption were developed.The results showed that the maximum relative error was less than 10%,and the new method was not significantly different from the DeST simulation(P>0.05).The accuracy of calculating energy requirements was improved by the solar-air degree-day method in the different climate zones.Orientation and surface color effects on energy consumption need to be considered,and external walls of different orientations should have different surface colors.

Optimum insulation thickness for the sandwich structure livestock buildings external envelopes in different climate regions of China

Determining the optimum insulation thicknesses of external envelopes for livestock buildings are one of the most effective metrics to decrease energy requirements.This study was carried out to determine the optimum insulation thicknesses for livestock buildings in different climate zones,to examine the effects of insulation thickness and material(foam glass,mineral wool,expanded polystyrene,foamed polyurethane,foamed polyvinyl chloride,and expanded polyethylene)on life cycle total cost,life cycle savings,and payback period.The finishing pig houses and laying hen buildings with sandwich wall structures(color steel laminboard)in five typical cities were studied using the degree-days method with economic models.Optimal insulation thicknesses ranged from 0.05 m to 0.25 m and 0.02 m to 0.24 m in finishing pig houses and poultry buildings,respectively;the life cycle total costs ranged from 16.49 to 37.98$/m2 and 13.37 to 36.84$/m2;the life cycle savings ranged from 29.13 to 220.60$/m2 and 0 to 202.13$/m2;and the payback period ranged from 1.11 to 5.81 years and 1.19 to 20.76 years,respectively.Foamed polyurethane provided the highest life cycle savings,while foam glass had the lowest.In this research,the insulation thicknesses for the sandwich structure livestock buildings external envelopes are optimized,and the energy saving can be obtained by using proper insulation thickness in different regions.Furthermore,it can increase the knowledge about energy consumption in the livestock buildings and the results can be also a useful tool for farmers.

Reducing feather pecking and cloacal cannibalism by providing layer breeders with nest boxes in colony cages for natural mating

Colony cages for natural mating have been applied on many layer breeder farms.However,feather pecking and cloacal cannibalism are considered as prominent problems for these systems.This study aimed to investigate the effects on feather pecking and vent pecking behaviors by providing layer breeders with nest boxes(0.90 m L×0.40 m W×0.60 m H)in colony cages for natural mating(4.80 m L×1.20 m W×0.71 m H).Video recording and artificial observation were adopted.The results showed that the usage of nest boxes gradually increased from the beginning of nest boxes providing at the age of 37 weeks to the end of the experiment at the age of 55 weeks.The utilization rates of nest boxes were 36.75%,44.75%and 50.38%at the ages of 41 weeks,47 weeks and 53 weeks,respectively.The hens in the cages without nest boxes showed significantly more frequent gentle feather pecks(both given and received)than hens in the cages with nest boxes at the ages of 41 weeks,47 weeks and 53 weeks.A decreasing trend of gentle feather pecking frequency(both given and received)was found with the increasing age for both the two groups.No significant difference was found in the number of given or received severe feather pecks at the age of 41 weeks.The hens in the cages without nest boxes showed a significantly higher frequency of given and received severe feather pecks than hens in the cages with nest boxes at the ages of 47 weeks and 53 weeks(p<0.05).Both cannibalistic injury occurrence and mortality rate in the cages with nest boxes were significantly lower than those in the cages without nest boxes.In conclusion,providing nest boxes in colony cages for natural mating could decrease abnormal pecking behaviors and improve animal welfare conditions of layer breeders.

Adaptability of pullets from cages to a large cage aviary unit system during the initial settling-in period

Pullets often raised in cage system from week 1 to week 13 in China,when transferred to aviary system after,there will be a problem with adapt.A large cage aviary unit(LCAU)system was developed,which allocated with facilities such as ramps to help cage reared hens to adapt to the multi-tier space.To investigate hens’adaptability to the new system,space use over time in the LCAU system during the first 10 days after hens transferred were recorded,instantaneous scan sampling and continuous focal sampling were used to assess the behavior difference of hens between the LCAU and conventional cage(CC)systems.On the first day of arrival,10.03% of hens reached the second tier(S2)and the third tier(S3)of the aviary.During the observation period,an average of 2.42% of hens climbed and stayed at the upper tiers every day.Space allowance on floor of the first tier(S1)increased from 444.62 cm^(2)/hen(91 d)to 586.32 cm^(2)/hen(100 d),which was more than 540 cm^(2)/hen in the CC system.Comfort behaviors in the LCAU system were significantly more than in the CC system(p<0.01)and hens performed more comfort behaviors with the increase of days after transferred.Hens ate and drank less in the LCAU system in the beginning,however,with the increasing use of upper space,hens ate and drank more and more in the LCAU system during the 10 days after transferred from CC system.Consequently,there were no difference of feed behavior between the CC and LCAU systems(p>0.05)on the last 5 days of the whole observing period.The results indicated that hens gradually learned to use the 3-dimensional space in the initial settling-in period and,gained a good welfare condition in LCAU system.Further studies are needed to investigate the three-dimensional preferences and behavior expression in difference period to bridge the gap in knowledge of space use capacity among adult laying hens.

Synthesis and optical properties of soluble low bandgap poly （pyrrole methine） with alkoxyl substituent

A soluble low bandgap poly （pyrrole methine） with alkoxyl substituent, poly {（3-hexanoyl）pyrrole-[2,5- diyl（p-tetradecyloxybenzylidene）]} （PHPDTBE）, was synthesized and characterized by 1H nuclear magnetic resonance （1H-NMR）, Fourier transform-infrared （FT-IR）, elemental analysis （EA） and gel permeation chromatography （GPC）. PHPDTBE was readily soluble in weak polar organic solvents. The absorption peaks of PHPDTBE solution and film were located at around 458 and 484 nm, respectively. The optical bandgaps of PHPDTBE film for indirect allowed and direct allowed transitions were measured to be 1.66 and 2.35 eV, respectively. PHPDTBE film had few defects in the energy band and the Urbach energy of PHPDTBE film was calculated to be about 0.19 eV. The resonant third-order nonlinear optical susceptibilities of PHPDTBE solution and film measured by degenerate four-wave mixing （DFWM） technique at 532nm were all in the order of 10 8 esu, which was about 1-3 orders of magnitude larger than that of the other ordinary n-conjugation polymers.

Modification of perchery system:Preference for ramps rather than ladders during early adaptation period for cage-reared pullets

Poor early adaptation in aviaries has adverse effects on welfare and the later production.Effects of system modification by ramps and ladders on early adaptation of birds were investigated.A total of 240 pullets and 24 cockerels of Yukou Jing Pink II parent stock were allocated into six perchery compartments at the age of 83 days from conventional cages.Three compartments were modified with ramps of different angles,30°,40°and 30°&50°combination.The other compartments were fitted with 2 ladders,with 22 cm steps and 33 cm steps.Spatial distribution of birds and eggs,as well as the data of ramps and ladders utilization were used to assess birds’adaptation and the effectiveness of modification facilities.A higher proportion of hens got onto the tiered platforms in ramp group(p<0.001)and engaged in feeding(p=0.002).Inversely more than 85.0%of hens dwelled on the system floor in the ladder group for the whole observation period.The proportion of birds feeding increased over time(p<0.001),with the proportion of birds lying decreasing(p<0.001).A higher frequency of utilization of ramps was found compared with ladders(4.5-25.8 vs.2.8-14.7 times/40 birds per hour).For ramp use,79.3%of hens negotiated level change by using 30°ramp and behavioral process was also found related with the type of ramps.On the contrary,very few successful level changes were observed via ladders and 60%of ladder use was ended with birds backing to the system floor.Besides,a higher proportion of non-nest eggs was recorded in ladder group in the early laying period.These results indicated that modification of ramps is more applicable for improving birds’early adaptation and later production in perchery system of multi-tier,especially for pullets reared in conventional cages.

A subpopulation of CD146^(+) macrophages enhances antitumor immunity by activating the NLRP3 inflammasome

As one of the main tumor-infiltrating immune cell types, tumor-associated macrophages (TAMs) determine the efficacy of immunotherapy. However, limited knowledge about their phenotypically and functionally heterogeneous nature restricts their application in tumor immunotherapy. In this study, we identified a subpopulation of CD146+ TAMs that exerted antitumor activity in both human samples and animal models. CD146 expression in TAMs was negatively controlled by STAT3 signaling. Reducing this population of TAMs promoted tumor development by facilitating myeloid-derived suppressor cell recruitment via activation of JNK signaling. Interestingly, CD146 was involved in the NLRP3 inflammasome-mediated activation of macrophages in the tumor microenvironment, partially by inhibiting transmembrane protein 176B (TMEM176B), an immunoregulatory cation channel. Treatment with a TMEM176B inhibitor enhanced the antitumor activity of CD146+ TAMs. These data reveal a crucial antitumor role of CD146+ TAMs and highlight the promising immunotherapeutic approach of inhibiting CD146 and TMEM176B.

Effects of ripple cross angles and turbulence models on wet curtain resistance

To study the influence of ripple cross angles on the resistance of wet curtains,wet curtains with different ripple cross angles(45°/45°,45°/15°)were tested on agricultural ventilation equipment performance testing benches,and the static pressure drop under different wind speeds(1-3 m/s)was determined.Four turbulence models(κ-ε,RNGκ-ε,κ-ω,SSTκ-ω)were adopted for numerical simulations of the two types of wet curtain,and the simulations’results were compared with those of experiments.The average errors found are 41.1%,48.7%,27.1%,and 27.8%,respectively,and theκ-ωmodel is found to be the most suitable one for the calculation of wet curtain resistance among the four turbulence models.By using theκ-ωturbulence model,the static pressure drop performances of wet curtains with ripple cross angles 45°/35°and 45°/25°were calculated.Resistance increases with wind speed and ripple cross angles,and a large ripple cross angle has a higher resistance growth rate with increasing wind speed.

Temporal changes in the characteristics of algae in Dianchi Lake,Yunnan Province,China

Algal blooms have become a worldwide environmental concern due to water eutrophication.Dianchi Lake in Yunnan Province,China is suffering from severe eutrophication and is listed in the Three Important Lakes Restoration Act of China.Hydrothermal liquefaction allows a promising and direct conversion of algal biomass into biocrude oil.In this study,algal samples were collected from Dianchi Lake after a separation procedure including dissolved air flotation with polyaluminum chloride and centrifugation during four months,April,June,August and October.The algal biochemical components varied over the period;lipids from 0.7%to 2.1%ash-free dry weight(afdw),protein from 20.9%to 33.4%afdw and ash from 36.6%to 45.2%dry weight.The algae in June had the highest lipid and protein concentrations,leading to a maximum biocrude oil yield of 24.3%afdw.Biodiversity analysis using pyrosequencing revealed different distributions of microbial communities,specifically Microcystis in April(89.0%),June(63.7%)and August(84.0%),and Synechococcus in April(2.2%),June(12.0%)and August(1.0%).This study demonstrated remarkable temporal changes in the biochemical composition and biodiversity of algae harvested from Dianchi Lake and changes in biocrude oil production potential.