Design of hadronic calorimeter for DarkSHINE experiment

The sensitivity of the dark photon search through invisible decay final states in low-background experiments relies sig-nificantly on the neutron and muon veto efficiencies,which depend on the amount of material used and the design of the detector geometry.This paper presents the optimized design of the hadronic calorimeter(HCAL)used in the DarkSHINE experiment,which is studied using a GEANT4-based simulation framework.The geometry is optimized by comparing a traditional design with uniform absorbers to one that uses different thicknesses at different locations on the detector,which enhances the efficiency of vetoing low-energy neutrons at the sub-GeV level.The overall size and total amount of material used in the HCAL are optimized to be lower,owing to the load and budget requirements,whereas the overall performance is studied to satisfy the physical objectives.

超声结合BRAFV600E基因突变检测在桥本甲状腺炎合并甲状腺结节鉴别中的应用价值

目的采用超声、BRAFV600E基因突变检测桥本甲状腺炎合并甲状腺结节,探讨两者联合检测对桥本甲状腺炎合并甲状腺结节良恶性的诊断价值。方法选取2017年9月—2019年10月在惠州市中心人民医院就诊的桥本甲状腺炎合并甲状腺结节患者329例为研究对象,根据病理确诊甲状腺结节良恶性分为恶性组(177例)和良性组(152例)。采用超声、BRAFV600E基因突变检测桥本甲状腺炎合并甲状腺结节情况,并分析超声、BRAFV600E基因突变及两者联合检测对桥本甲状腺炎合并甲状腺结节良恶性的诊断价值。结果金标准、超声、BRAFV600E基因突变诊断甲状腺炎合并甲状腺结节恶性分别为177例、167例、163例,良性分别为152例、162例、166例。超声、BRAFV600E基因突变、两者联合检测桥本甲状腺炎合并甲状腺结节恶性的敏感性分别为72.31%、65.54%和85.31%,特异性分别为74.34%、69.08%和71.71%,准确度分别为73.25%、67.17%和79.03%。与超声比较,两者联合诊断敏感性较高(P<0.0125),BRAFV600E基因突变诊断准确度较低(P<0.0125);与BRAFV600E基因突变比较,两者联合诊断敏感性、准确度较高(P<0.0125)。结论超声、BRAFV600E基因突变均对桥本甲状腺炎合并甲状腺结节良恶性具有一定诊断价值,单两者联合优于单独诊断。

Effects of process parameters on microstructure and wear resistance of TiN coatings deposited on TC11 titanium alloy by electrospark deposition

In the present study,the effects of process parameters(output voltage x,nitrogen flux l and specific strengthening time s)on the microstructure and wear resistance properties of TiN coatings prepared by electrospark deposition(ESD)were investigatedsystematically.The microstructure of the coatings was characterized for thickness(TOC),content of TiN(CON)and porosity(POC).A statistical model was developed to identify the significant factors affecting the microstructure and wear resistance of the coatings.The results show that the output voltage x and nitrogen flux l present significant effects on majority of the evaluation indexes such asTOC,friction coefficient(COF)and wear mass loss(Id),while the specific strengthening time s has a significant effect on POC and asmall effect on the other indexes.The optimal process parameters were obtained as follows:output voltage(x,60V),nitrogen flux(l,15L/min)and specific strengthening time(s,3min/cm2).The variation of wear mass loss(Id)by the variation of the outputvoltage(x)and nitrogen flux(l)is attributed to the change of wear mechanisms of TiN coatings.The main wear mechanism of TiNcoating prepared under optimal process parameters is micro-cutting wear accompanied by micro-fracture wear.

Review of gallium oxide based field-effect transistors and Schottky barrier diodes

Gallium oxide(Ga_2O_3), a typical ultra wide bandgap semiconductor, with a bandgap of ~4.9 e V, critical breakdown field of 8 MV/cm, and Baliga's figure of merit of 3444, is promising to be used in high-power and high-voltage devices.Recently, a keen interest in employing Ga_2O_3 in power devices has been aroused. Many researches have verified that Ga_2O_3 is an ideal candidate for fabricating power devices. In this review, we summarized the recent progress of field-effect transistors(FETs) and Schottky barrier diodes(SBDs) based on Ga_2O_3, which may provide a guideline for Ga_2O_3 to be preferably used in power devices fabrication.

腹腔镜下胃十二指肠溃疡穿孔的修补方式选择

目的探讨腹腔镜在治疗胃十二指肠溃疡穿孔中修补方法的选择及治疗经验.方法回顾性分析2014年5月-2018年5月60例腹腔镜下胃十二指肠穿孔修补的临床病例资料及手术情况,根据修补方法分"8"字缝合组(5例)、间断缝合组(34例)和连续缝合组(21例),对比各组平均穿孔大小(mm)、平均缝合时间(min)、缝合过程中出血量(ml)、轻微并发症(腹胀、发热、腹泻和呕吐)及黑便发生例数.结果"8"字缝合组缝合时间及出血量均少于后两组,但仅适用于≤5.0 mm穿孔;连续缝合组平均缝合时间14.27 min、缝合过程中出血量12.34 ml明显少于间断缝合组(32.34 min和30.25 ml),差异均有统计学意义(P<0.05),且其在平均穿孔大小、轻微并发症发生例数和黑便例数上比较,差异均无统计学意义(P>0.05).结论腹腔镜手术治疗胃十二指肠溃疡穿孔具有创伤小、并发症少等优点.对于≤5.0 mm穿孔建议采用"8"字缝合法,操作简便,缝合迅速;对于>5.0 mm穿孔应用连续缝合具有高效、可靠等优点.

TfR1 Extensively Regulates the Expression of Genes Associated with Ion Transport and Immunity

Transferrin receptor 1(TfR1),encoded by the TFRC gene,is the gatekeeper of cellular iron uptake for cells.A variety of molecular mechanisms are at work to tightly regulate TfR1 expression,and abnormal TfR1 expression has been associated with various diseases.In the current study,to determine the regulation pattern of TfR1,we cloned and overexpressed the human TFRC gene in HeLa cells.RNA-sequencing(RNA-seq)was used to analyze the global transcript levels in overexpressed(OE)and normal control(NC)samples.A total of 1669 differentially expressed genes(DEGs)were identified between OE and NC.Gene ontology(GO)analysis was carried out to explore the functions of the DEGs.It was found that multiple DEGs were associated with ion transport and immunity.Moreover,the regulatory network was constructed on basis of DEGs associated with ion transport and immunity,highlighting that TFRC was the node gene of the network.These results together suggested that precisely controlled TfR1 expression might be not only essential for iron homeostasis,but also globally important for cell physiology,including ion transport and immunity.

Polarization control and tuning efficiency of tunable vertical-cavity surface-emitting laser with internal-cavity sub-wavelength grating

We design an 850 nm tunable vertical-cavity surface-emitting laser(VCSEL)structure using an internal-cavity sub-wavelength grating.The use of such a tuning structure allows for wider wavelength tuning range and more stable single-polarization as compared to conventional tunable VCSELs.The features of the internal-cavity grating effect on the wavelength tuning and polarization characteristics of the tunable VCSEL are analyzed.The simulation results show that the largest wavelength tuning range achieves 44.2 nm,and the maximum orthogonal polarization suppression ratio(OPSR)is 33.4 dB(TE-type)and 38.7 dB(TM-type).

Variability of Young Stellar Objects in the Perseus Molecular Cloud

We present an analysis of 288 young stellar objects(YSOs)in the Perseus molecular cloud that have well defined g and r-band lightcurves from the Zwicky Transient Facility.Of the 288 YSOs,238 sources(83%of our working sample)are identified as variables based on the normalized peak-to-peak variability metric,with variability fraction of 92%for stars with disks and 77%for the diskless populations.These variables are classified into different categories using the quasiperiodicity(Q)and flux asymmetry(M)metrics.Fifty-three variables are classified as strictly periodic objects that are well phased and can be attributed to spot modulated stellar rotation.We also identify 22 bursters and 25 dippers,which can be attributed to accretion burst and variable extinction,respectively.YSOs with disks tend to have asymmetric and non-repeatable lightcurves,while the YSOs without disks tend to have(quasi)periodic lightcurves.The periodic variables have the steepest change in g versus g-r,while bursters have much flatter changes than dippers in g versus g-r.Periodic and quasiperiodic variables display the lowest variability amplitude.Simple models suggest that the variability amplitudes of periodic variables correspond to changes of the spot coverage of 30%-40%,burster variables are attributed to accretion luminosity changes in the range of L_(acc)/L_(*)=0.1-0.3,and dippers are due to variable extinction with A_(V)changes in the range of 0.5-1.3 mag.

Large-scale CO(J=1-0)Observations toward the M120.1+3.0 Molecular Cloud:A Filament with a Chain of Starburst Clusters

We present large-scale(2°×2°)observations toward the molecular cloud M120.1+3.0,using ^(12)CO,^(13)CO and C^(18)O(J=1-0)data from the Purple Mountain Observatory 13.7 m millimeter telescope.The distance of the cloud is measured to be~1.1 kpc.Using the ^(13)CO data,we identify a main filament F1 and two sub-filaments F2 and F3 in the cloud,which together show a"hub-filament"structure.Filaments F1 and F2 are thermally supercritical.Furthermore,F1 displays clear localized systematic motions in the ^(13)CO position-velocity diagram,which could be explained by accretion along the filament.The mean estimated accretion rate is~132M_(⊙)Myr^(-1).Approximately 150 ^(13)CO clumps are identified in the cloud,of which 39 are gravitationally bound.Most of these virialized clumps are well distributed along the supercritical filaments F1 and F2.Based on the complementary infrared and optical data,we identify~186 young stellar objects in the observed area and extract five clusters within the dense ridge of F1.The calculated star formation rate(SFR)surface densities(∑_(SFR))in the clusters range from 1.4 to 2.5 M_(⊙)Myr^(-1)pc^(-2),with a mean value of~2.0M_(⊙)Myr^(-1)pc^(-2).We therefore regard them as mini-starburst cluster candidates.The comparison between ∑_(SFR) and column density N_(gas) along the skeleton of F1 suggests that star formation is closely related to the dense gas in the cloud.Along the main filament F1,five bipolar outflows are also found.All these results indicate intense star-forming activities in the M120.1+3.0 molecular cloud.

Erratum to: TfRl Extensively Regulates the Expression of Genes Associated with Ion Transport and Immunity

It is hereby certified that there is no shared co-first authorship in this paper.Dr.Nan HUANG is the only first author of this article.

Restriction fragment length polymorphism in the exon 2 of the BoLA-DRB3 gene in Chinese Holstein of the south China

The genetic diversity of the exon2 of BoLA-DRB3 (BoLA-DRB3.2) in Chinese Holstein cattle of the south China was investigated by hemi-nested polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. Six, four and eleven RFLP patterns were found after digestion with the restriction enzymes Hae III, Bst YI and Rsa I, respectively. The DNA sequence showed and twenty- five DRB3.2 alleles. GLM model analysis indicated that lactation and calving season have positive correlation with SCC (Somatic Cell Count) (p<0.01), BoLA-DRB3.2*3, *8, *18 and *26 were associated with lower SCC (p<0.01). The present findings concluded that mastitis is a severe hinder of milk production and technology. Therefore, future re-searches should focus on associations of mastitis with BoLA haplotypes rather than single BoLA

A cellular scale numerical study of the effect of mechanical properties of erythrocytes on the near-wall motion of platelets

The effect of mechanical properties of erythrocytes on the near-wall motion of platelets was numerically studied with the immersed boundary method. Cells were modeled as viscous-fluid-filled capsules surrounded by hyper-elastic membranes with negligible thickness. The numerical results show that with the increase of hematocrit, the near-wall approaching of platelets is enhanced, with which platelets exhibit larger deformation and orientation angle of its near-wall tank-treading motion, and the lateral force pushing platelets to the wall is increased with larger fluctuation amplitude. Meanwhile the near-wall approaching is reduced by increasing the stiffness of erythrocytes.

Evolutionary stages and disk properties of young stellar objects in the Perseus cloud

We investigated the evolutionary stages and disk properties of 211 young stellar objects（YSOs） across the Perseus cloud by modeling their broadband optical to mid-infrared（IR） spectral energy distribution（SED）. Our optical gri photometry data were obtained from the recently finished Purple Mountain Observatory Xuyi Schmidt Telescope Photometric Survey of the Galactic Anti-center（XSTPS-GAC）.About 81% of our sample fall into the Stage II phase which is characterized by having optically thick disks, while 14% into the Stage I phase characterized by having significant infalling envelopes, and the remaining 5% into the Stage Ⅲ phase characterized by having optically thin disks. The median stellar age and mass of the Perseus YSOs are 3.1 Myr and 0.3 M⊙ respectively. By exploring the relationships among the turnoff wave bands λturnoff（longward of which significant IR excesses above the stellar photosphere are observed）, the excess spectral index αexcess as determined for λ 〉 λturnoff, and the disk inner radius Rin（determined from SED modeling） for YSOs at different evolutionary stages, we found that the median and standard deviation of αexcess for YSOs with optically thick disks tend to increase withλturnoff, especially at λturnoff ≥5.8 μm, whereas the median fractional dust luminosities Ldust/L★ tend to decrease with increasing λturnoff. This points to an inside-out process of disk clearing for small dust grains. Moreover, a positive correlation between αexcess and Rin was found at α〉excess ～ 0 and R〉in～ 10 × the dust sublimation radius Rsub, irrespective of λturnoff, Ldust/L★ and disk flaring. This suggests that the outer disk flaring either does not evolve synchronously with the inside-out disk clearing of small dust grains or has little appreciable influence on the spectral slopes at λ〈～ 24 μm. About 23% of our YSO disks are classified as transitional disks, which haveλturnoff ≥ 5.8 μm and Ldust/L★ 〉 10-3. The transitional disks and full disks occupy distinctly different regions on the Ldust/L★ vs. αexcess diagram. Taking Ldust/L★ as an approximate discriminator of disks with（〉0.1） and without（〈0.1） considerable accretion activity, we found that 65% and 35% of the transitional disks may be consistent with being dominantly cleared by photoevaporation and dynamical interaction with giant planets respectively. None of our transitional disks have αexcess（〈0.0） or Ldust/L★（〉0.1） values that would otherwise be suggestive of disk clearing dominanted by grain growth.

A Dielectric Ink Combining Acrylate and Cyanate Moieties for Inkjet 3D Printing with Good Thermal Stability

Inkjet 3D printing has potential in the additive manufacturing of electronic circuits and devices.However,inks that can be used for printing layers with T5%>300℃ or hardness>200 MPa have been rarely reported.Cyanate ester(CE)polymers have excellent thermal stability,high strength,and low shrinkage compared to other common dielectric inks for inkjet 3D printing,but cannot be quickly shaped by ultraviolet(UV)irradiation or thermal treatment.Combining CEs with UV-curable monomers may be a possible way to accelerate crosslinking,but there are challenges from the adverse effects of the dilution of both monomers.In this study,dielectric inks with acrylate and cyanate moieties were developed.The low viscosity and surface tension of the CE precursor(Bisphenol E cyanate ester)were combined with photocurable acrylate diluent monomers and cross-linker to realize an ink suitable for inkjet 3D printing.An internal dual three-dimensional cross-linked network structure resin was prepared by a combination of photocuring and thermal curing with T5%up to 326.69℃,hardness up to 431.84 MPa,dielectric constant of 2.70 at 8 GHz,and shrinkage of 1.64%.The developed dielectric inks can be applied to the 3D printing of printed circuit boards and other electronic devices that require dielectric properties.

Influence of oxygen-rich hot air composite gas medium on sintering performance and function mechanism

Hot air sintering technology is used to improve the quality and production efficiency of sintered ore.However,the current thick layer condition highlights the disadvantage of the low oxygen potential of the hot air sintering layer.Therefore,it is considered to use oxygen enrichment sintering to improve the environment of hot air sintering.Traditional sintering,hot air sintering,and oxygen-rich hot air sintering were compared through sintering cup experiments,and the influence of hot air and oxygen-rich hot air on sintering indexes was clarified.Hot air reduced the vertical sintering velocity,while improved the yield and tumbler index.Oxygen-rich hot air sintering contributed to improving the vertical sintering velocity while ensuring the quality of sintered ore,thus comprehensively improving production efficiency.Under the action of hot air,the highest temperature of the sintering layer increased and the high-temperature holding time was prolonged.After oxygen enrichment,the combustion efficiency of fuels in the upper layer of materials was promoted,which optimized heat distribution in the middle and lower layers of materials and increased the content of calcium ferrite in the sintered ore,thus strengthening the sintering process.

Tribological properties of laser cladding TiB_2 particles reinforced Ni-base alloy composite coatings on aluminum alloy

To improve the wear resistance of aluminum alloy frictional parts, Ti B2particles reinforced Ni-base alloy composite coatings were prepared on aluminum alloy 7005 by laser cladding. The microstructure and tribological properties of the composite coatings were investigated. The results show that the composite coating contains the phases of Ni Al, Ni3Al, Al3Ni2, TiB2, TiB, TiC, CrB, and Cr23C6.Its microhardness is HV0.5855.8, which is 15.4 % higher than that of the Ni-base alloy coating and is 6.7 times as high as that of the aluminum alloy. The friction coefficients of the composite coatings are reduced by 6.8 %–21.6 % and 13.2 %–32.4 % compared with those of the Ni-base alloy coatings and the aluminum alloys, while the wear losses are 27.4 %–43.2 % less than those of the Ni-base alloy coatings and are only 16.5 %–32.7 % of those of the aluminum alloys at different loads. At the light loads ranging from 3 to 6 N, the calculated maximum contact stress is smaller than the elastic limit contact stress. The wear mechanism of the composite coatings is micro-cutting wear, but changes into multi-plastic deformation wear at 9 N due to the higher calculated maximum contact stress than the elastic limit contact stress. As the loads increase to 12 N, the calculated flash temperature rises to 332.1 °C.The composite coating experiences multi-plastic deformation wear, micro-brittle fracture wear, and oxidative wear.

Prospective study of light dark matter search with a newly proposed DarkSHINE experiment

Dark photons have been well motivated as strong candidates for dark force carriers and light dark matter in the sub-GeV mass range.Compared with collider experiments,fixed-target experiments provide a complementary approach to searching for dark photons,particularly in the lower mass range.We have studied the physics potential of the electron-on-target experiment based on the Shanghai SHINE facility,which provides 10 MHz single electron beam at 8 GeV energy.This analysis focuses on dark photons being produced via electron and nucleon interaction and then decays to dark matter candidates,which escape detection as missing momentum in the detector.This experiment takes advantage of using missing momentum to enhance signal versus background separation power.In this study,signal samples as a function of dark photon mass and an inclusive background sample with 2.5 billion events are simulated with GEANT4.For better background estimates,major rare background processes have also been simulated.This paper presents the experiment and detector design,signal and background simulations,analysis strategy,and the prospective study of the experiment sensitivity.With 9×10^(14) electron-on-target events(about three years running),this experiment is expected to rule out most of the sensitive regions predicted by popular dark photon models.

A novel rat model of seminal vesiculitis

We aimed to establish a novel rat model of seminal vesiculitis that would provide an effective approach to investigate the pathogenesis of this disease in the future. Eight male rats received the same operation, during which the root of one of the two seminal vesicles was partly ligatured with sutures and the other vesicle was left in tact. The samples of seminal vesicles were harvested on the 8th day followi ng the operation. Hematoxylin and eosi n and Mass on's trichrome stains were used to observe the histopathology and the presenee of fibrous tissue in seminal vesicles, respectively. Immunoblotting and immunohistochemistry were applied to determine the tumor n ecrosis factor-alpha and cyclooxygenase-2 levels in semi nal vesicle tissues. Real-time fluoresce nee qua ntitative polymerase chain reaction was performed to measure the gene expression levels of proinflammatory cytokines. H2O2 levels in the seminal plasma from the seminal vesicle were also measured. Hematoxylin and eosin staining suggested that there was inflammatory cell in filtration into the semi nal vesicles treated by partial root ligati on. The tumor n ecrosis factor-alpha and cyclooxygenase-2 proteins were significantly upregulated in the treated seminal vesicles. The tumor necrosis factor-alpha, cyclooxygenase, interleukin 6, and inducible nitric oxide synthase mRNA expression levels were also upregulated in the treated seminal vesicles. The H2O2 levels in the seminal plasma from seminal vesicles with partial root ligation were significantly elevated compared with those from vesicle left intact. In conclusion, partially ligating the root of the seminal vesicle via sutures in rats is an effective method to establish a seminal vesiculitis rat model.

Correlation between Conformation Change of Polyelectrolyte Brushes and Lubrication

We directly monitor the absolute separation profiles that function as film thickness between a single glass disk and the charged polyelectrolyte brushes decorated steel slider in water using a home-made slider-on-disk apparatus, which reflects the structural conformation variations and interactions of polymer brushes under externally applied pressure, in addition to probing the relative variation of friction forces under different applied loads and sliding velocities. We find that the polyelectrolyte brushes modified surfaces can sustain high pressure and have extremely low friction coefficients（around 0.006 at pressures of 0.13 MPa; 0.5-0.6 without brushes）. The water-lubrication characteristics are correlated to the structural conformation changes of the polyelectrolyte brushes that are mainly governed by electrostatic interactions and the osmotic pressure of counterions inside the polymer chains, which can be used to support and distribute the normal pressure. The apparent thickness of the brush decreases with the increase of loading forces, an increase in the ionic strength causes the polymer chains collapse, and the friction forces increase. This fundamental research is of great importance to understand the mechanical and structural properties of polyelectrolyte brushes and their influences on the tribological behaviors, and helps to design friction/lubrication-controlled surface/interface by taking advantage of polyelectrolyte brushes.

Revisiting Newton’s rings with a plasmonic optical flat for high-accuracy surface inspection

Two parallel optical surfaces often exhibit colorful fringes along the lines of equal thickness because of the interference of light.This simple phenomenon allows one to observe subwavelength corrugations on a reflective surface by simply placing on it a flat reference dielectric surface,a so-called optical flat,and inspecting the resultant interference pattern.In this work,we extend this principle from dielectric surfaces to two-dimensional plasmonic nanostructures.Optical couplings between an Au nanodisk array and an Au thin film were measured quantitatively using two different techniques,namely,the classical Newton’s rings method and a closed-loop nano-positioning system.Extremely high spectral sensitivity to the inter-surface distance was observed in the near-field coupling regime,where a 1-nm change in distance could alter the resonance wavelength by almost 10 nm,440 times greater than the variation in the case without near-field coupling.With the help of a numerical fitting technique,the resonance wavelength could be determined with a precision of 0.03 nm,corresponding to a distance precision as high as 0.003 nm.Utilizing this effect,we demonstrated that a plasmonic nanodisk array can be utilized as a plasmonic optical flat,with which nanometer-deep grooves can be directly visualized using a low-cost microscope.