The urban-rural equalized development （URED） as a definite measure and operating model is beneficial to gradually eliminating the dual-track structure of urban-rural development, bridging the gap of urban-rural deve...The urban-rural equalized development （URED） as a definite measure and operating model is beneficial to gradually eliminating the dual-track structure of urban-rural development, bridging the gap of urban-rural development, and creating harmonious urban-rural interactions. This paper aims to explore the status quo of URED in China at prefecture level, and to reveal the spatio-temporal patterns of URED and its differentiation regularity. The results show that： （1） China＇s URED level can be categorized into two parts, i.e., the eastern and the western, according to the ＂HU Huanyong Line＂, presenting a pattern of ＂east high and west low＂ and the URED level improves on the whole with the increase of distance from the line; （2） China＇s URED level can also be categorized into the northern and the southern parts according to ＂Kunlun-Qinling-Huaihe Line＂, presenting a pattern of ＂north high and south low＂, and the URED level reduces on the whole with the increase of distance from the line; （3） At the national level, China＇s URED has a significant trend of spatial agglomeration, the high and low URED regions tend to be adjacent, namely, the URED level presents obvious regional unbalance; （4） The five sub-dimension indicators of the URED level in the geographical space also reveal similar regional differentiation pattern, and in the aspect of space a decreasing trend is found in the URED level from the eastern （northern coast, eastern coast and southern coast）, the northeastern, the central （the middle reaches of the Yangtze River and the Yellow River） to the western （northwest and southwest）; and （5） China＇s URED at prefecture-level city can be divided into five types of differentiation areas. This study contributes to promoting the integrative cognition of the status quo of China＇s URED and can serve as a scientific ref- erence concerning the decision-making of coordinating urban-rural development and of pushing forward new-type urbanization strategy in China.展开更多
Abstract There are many soft-rock roadway coal mines in China. The surrounding rocks of the high-stress soft-rock roadways in deep mine are especially difficult to be supported using the traditional supporting way. In...Abstract There are many soft-rock roadway coal mines in China. The surrounding rocks of the high-stress soft-rock roadways in deep mine are especially difficult to be supported using the traditional supporting way. In this study, the south wing rail roadway on the second level of Yunjialing coal mine in China was used as an example to analyze the deformation and failure characteristics and influencing factors of roadway. On this basis, this study proposed the equalized yielding support idea which employs the yielding rings to realize the pressure equalization on the bolts and cables in the section. To achieve this purpose, the first bolt-mesh-cable equalizing pressure yielding support was integrated with the second grouting reinforcement. The results proved that the yield rings of the bolts and cables on the spandrel of the arched roadway firstly developed yielding deformation; then the deformation extended to the vault of the roadway; the bolts and cables achieved a yielding extreme value of 15 and 18 tonnes, respectively. The roadway surrounding rock tended to be stable at the 26th day after the maintenance. The equalizing pressure yielding supporting technology plays a moderate pressure-releasing and actively controlling role on the surrounding rocks in the soft-rock roadway with large deformation.展开更多
We take the contribution of all valence electrons into consideration and propose a new valence electrons equilibration method to calculate the equalized electronegativity including molecular electronegativity, group e...We take the contribution of all valence electrons into consideration and propose a new valence electrons equilibration method to calculate the equalized electronegativity including molecular electronegativity, group electronegativity, and atomic charge. The ionization potential of alkanes and mono-substituted alkanes, the chemical shift of 1H NMR, and the gas phase proton affinity of aliphatic amines, alcohols, and ethers were estimated. All the expressions have good correlations. Moreover, the Sanderson method and Bratsch method were modified on the basis of the valence electrons equilibration theory. The modified Sanderson method and modified Bratsch method are more effective than their original methods to estimate these properties.展开更多
In this Letter,we propose and experimentally demonstrate,to the best of our knowledge,a novel compact power-equalized multi-wavelength laser(MWL)source for optical I/O technology.This multi-wavelength distributed feed...In this Letter,we propose and experimentally demonstrate,to the best of our knowledge,a novel compact power-equalized multi-wavelength laser(MWL)source for optical I/O technology.This multi-wavelength distributed feedback(DFB)laser array is used to achieve simultaneous emission of multiple wavelengths with balanced output power and stable single-mode operation.The reconstruction equivalent chirp technique is used to design and fabricate theπ-phase shifted DFB laser array to achieve precise wavelength spacing.The power equalizers(PEs)are monolithically integrated in front of the laser unit to equalize the output power.The experimental results show that the wavelength spacing of the proposed eight-channel MWL is 100 G±4.38 G,and the maximum deviation of the intensity(MDOI)is 1.00 dB under a 25℃working environment.Compared with the traditional MWL structure,the wavelength spacing error is reduced from 0.32 to 0.035 nm,and the MODI is reduced from 3.8 to 1.0 dB.The output power exceeds 25 mW when the current injected into the semiconductor optical amplifier(SOA)is 150 mA.Besides,the relative intensity noise(RIN)of all wavelengths is below-138 dB/Hz,and clear 25 Gb/s non-return-to-zero(NRZ)eye diagrams are obtained for the eight wavelengths with the external lithium-niobate Mach-Zehnder modulator.The superior performance of the proposed MWL makes it a promising method for low-bit-error optical I/O links and high-density chip interconnection systems.展开更多
The ionization potential of organic homologs can be expressed as I_p=(∑X_i)/(a+bn).Here, X_i is the electronegativity(the average energy of valence electrons in a ground-state free atom)of the ith atom in an organic ...The ionization potential of organic homologs can be expressed as I_p=(∑X_i)/(a+bn).Here, X_i is the electronegativity(the average energy of valence electrons in a ground-state free atom)of the ith atom in an organic homologous molecule;n,the number of repeating units in the molecule;and(a+bn),the electron moving range in the molecule orbit.The results of linear regression analysis show that the correlation coefficients r are all 'excellent'(r>0.990)for the 146 sets of photo electron spectroscopy data of 42 organic homologous series.展开更多
In DSP-based SerDes application,it is essential for AFE to implement a pre-ADC equalization to provide a better sig-nal for ADC and DSP.To meet the various equalization requirements of different channel and transmitte...In DSP-based SerDes application,it is essential for AFE to implement a pre-ADC equalization to provide a better sig-nal for ADC and DSP.To meet the various equalization requirements of different channel and transmitter configurations,this paper presents a 112 Gbps DSP-Based PAM4 SerDes receiver with a wide band equalization tuning AFE.The AFE is realized by implementing source degeneration transconductance,feedforward high-pass branch and inductive feedback peaking TIA.The AFE offers a flexible equalization gain tuning of up to 17.5 dB at Nyquist frequency without affecting the DC gain.With the pro-posed AFE,the receiver demonstrates eye opening after digital FIR equalization and achieves 6×10^(-9) BER with a 29.6 dB inser-tion loss channel.展开更多
On the evening of May 3Oth,the parallel forum"Equality and Inclusiveness&Harmonious Coexistence:Multi-dimensional Narratives of Civilisations from Writers'Perspective",as part of the 4th Dialogue on ...On the evening of May 3Oth,the parallel forum"Equality and Inclusiveness&Harmonious Coexistence:Multi-dimensional Narratives of Civilisations from Writers'Perspective",as part of the 4th Dialogue on Exchanges and Mutual Learning among Civilisations,was held in Dunhuang.The forum was organised by the China Writers Association and co-organised by China National Publications Import&Export(Group)Corporation.展开更多
A new cyclic prefix(CP)-based nonoverlapping FBMC-QAM(CP-NO-FBMC-QAM)system with two prototype filters is proposed in this paper,which satisfies complex orthogonality conditions and good frequency energy confinement a...A new cyclic prefix(CP)-based nonoverlapping FBMC-QAM(CP-NO-FBMC-QAM)system with two prototype filters is proposed in this paper,which satisfies complex orthogonality conditions and good frequency energy confinement at the same time.We analyze its inter-carrier interference/inter-symbol interference(ICI/ISI)over multipath channels.Owing to the additional CP,the ISI of received symbols over multipath channels is eliminated in the proposed system,and the resulting improvement in the signal-to-interference ratio(SIR)performance is evaluated by theoretical analysis.Moreover,for the ICI caused by multipath propagation in received symbols,we develop a method that eliminates the ICI by frequency-domain channel estimation and equalization before the receiver filtering process.The proposed CP-NO-FBMC-QAM system and ICI cancellation method(ICICM)are validated by comparisons of implementation complexity,power spectral density(PSD),bit error rate(BER)and channel estimation performance with conventional CP-based orthogonal frequency division multiplexing(CP-OFDM)and FBMC-QAM systems.展开更多
Under the background of accelerated global cultural exchange and information dissemination,reading has become a crucial component of public cultural services.Public libraries in Nordic countries(Denmark,Sweden,Norway,...Under the background of accelerated global cultural exchange and information dissemination,reading has become a crucial component of public cultural services.Public libraries in Nordic countries(Denmark,Sweden,Norway,Finland,Iceland)stand out by adhering to the core philosophy of“universal sharing and equal reading”,integrating reading promotion into national strategies,and constructing extensive service networks through sound legal guarantees and adequate financial support.This study identifies four key strategies for universality and equality in Nordic public libraries:covering all age groups,eliminating group differences,integrating digital and physical resources,and ensuring the right to read through legislative,financial,and other institutional support.These provide a reference for global public cultural services.展开更多
To improve image quality under low illumination conditions,a novel low-light image enhancement method is proposed in this paper based on multi-illumination estimation and multi-scale fusion(MIMS).Firstly,the illuminat...To improve image quality under low illumination conditions,a novel low-light image enhancement method is proposed in this paper based on multi-illumination estimation and multi-scale fusion(MIMS).Firstly,the illumination is processed by contrast-limited adaptive histogram equalization(CLAHE),adaptive complementary gamma function(ACG),and adaptive detail preserving S-curve(ADPS),respectively,to obtain three components.Then,the fusion-relevant features,exposure,and color contrast are selected as the weight maps.Subsequently,these components and weight maps are fused through multi-scale to generate enhanced illumination.Finally,the enhanced images are obtained by multiplying the enhanced illumination and reflectance.Compared with existing approaches,this proposed method achieves an average increase of 0.81%and 2.89%in the structural similarity index measurement(SSIM)and peak signal-to-noise ratio(PSNR),and a decrease of 6.17%and 32.61%in the natural image quality evaluator(NIQE)and gradient magnitude similarity deviation(GMSD),respectively.展开更多
THE world should be celebrating the creation of the United Nations(UN)80 years ago.However,its very existence is threatened.China recognizes the UN as the core of the international system.The UN Charter is a legal tre...THE world should be celebrating the creation of the United Nations(UN)80 years ago.However,its very existence is threatened.China recognizes the UN as the core of the international system.The UN Charter is a legal treaty under which national governments freely agree to uphold values and principles of behaviour.As a manifestation of the principle of“the sovereign equality of members,”each has an equal vote in the General Assembly.展开更多
Zn–Ag alloys are highly promising materials for fabricating biodegradable orthopedic implants.Nonetheless,they suffer from inferior strength.A Zn–2.5Ag alloy was alloyed with different contents of Mg(0.08,0.5,and 1 ...Zn–Ag alloys are highly promising materials for fabricating biodegradable orthopedic implants.Nonetheless,they suffer from inferior strength.A Zn–2.5Ag alloy was alloyed with different contents of Mg(0.08,0.5,and 1 wt.%)and then processed by equal channel angular pressing.Tensile tests and microstructure observation were conducted to investigate the impact of Mg addition on the microstructure and mechanical properties of Zn–2.5Ag alloy.Zn–2.5Ag alloy exhibits an ultrahigh elongation(EL)of 120.4%but a poor yield strength(YS)of 90.1 MPa,because of phase boundary sliding(PBS).Mg addition inhibits PBS and thus dramatically enhances YS but lowers EL.Specifically,YS of Zn–2.5Ag alloys containing Mg of 0.08%,0.5%,and 1%is 257.0,291.8,and 322.6 MPa,respectively.The alloys with 0.08%and 0.5%Mg possess an EL of around 30%,while the alloy with 1%Mg has an EL of only 11.0%.YS and EL of Zn–2.5Ag–0.5Mg alloy surpass that needed by orthopedic implants by 45.9%and 106.0%,respectively.Grain refinement strengthening is the main contributor to high strength.It is speculated that deformation twinning suppression and<c+a>pyramidal slip activation contribute to good ductility.展开更多
The effect of rotational-die equal channel angular pressing(RD-ECAP)temperature and deformation route on the microstructure and mechanical properties of pre-extruded Mg-5Gd-3Y-1Zn-0.5Zr(wt%)alloys were investigated.Th...The effect of rotational-die equal channel angular pressing(RD-ECAP)temperature and deformation route on the microstructure and mechanical properties of pre-extruded Mg-5Gd-3Y-1Zn-0.5Zr(wt%)alloys were investigated.The results indicate that the RD-ECAP updates both theα-Mg texture and long-period stack-ing ordered(LPSO)arrangement in the pre-extruded alloy,while theα-Mg texture is more sensitive to the change of deformation route.The LPSO streamlines modify the anisotropy of mechanical properties of the ECAP alloys via exerting different reinforcing effects and modifying the crack propagation.The lower ECAP temperature of 350℃ rather than 400℃ promotes dynamic precipitation which deteriorates the following ageing-hardening response but conduces to refining theα-Mg grains and preventing a sharp drop in elongation after peak ageing.The 350A peak-aged alloy exhibits the optimal mechanical proper-ties with the average tensile yield strength(TYS)of 311 MPa(S_(TYS)=3.7,S indicates standard deviation)and elongation of 7.6%(S_(EL)=0.7).Its higher strength should mainly be attributed to the finer grain size,and its quasi-isotropic performance should be inherited from the ECAP state induced by the rational arrangement of LPSO phases.展开更多
The Global Leaders’Meeting on Women was held in Beijing,the capital of China,on 13-14 October.South African Minister in the Presidency for Women,Youth and Persons with Disabilities Sindisiwe Chikunga,attended the eve...The Global Leaders’Meeting on Women was held in Beijing,the capital of China,on 13-14 October.South African Minister in the Presidency for Women,Youth and Persons with Disabilities Sindisiwe Chikunga,attended the event.ChinAfrica spoke with her in an exclusive interview about the messages she brought to the meeting,South Africa’s progress in women’s empowerment,how the G20 presidency can contribute to this cause,and China’s role.An edited excerpt of the interview follows.展开更多
Precipitation via thermal treatments is among the most effective approaches to strengthening and is widely applied in the Al industry. Thermal treatments combined with deformation are capable of finely regulating the ...Precipitation via thermal treatments is among the most effective approaches to strengthening and is widely applied in the Al industry. Thermal treatments combined with deformation are capable of finely regulating the process of precipitation and distribution of precipitates. Deformation-induced defects exert significant impacts on the precipitation and already present precipitates, which however is often overlooked. In this study, the interactions between deformation and precipitation/precipitates, and their impacts on mechanical properties were systematically investigated in the solution-treated (ST) Al-0.61Mg-1.17Si-0.5Cu (wt.%), processed by multi-pass equal channel angular pressing (ECAP) and thermal treatments. Novel deformation-mediated cyclic evolution of precipitates is discovered: ST→ (1,2 passes: deformation induced precipitation) Guinier Preston (GP) zones→ (An250/30) Q’ and L phases→ (3-pass: deformation induced fragmentation/resolution) spherical precipitates→ (4-pass: deformation induced further fragmentation/resolution) GP zones. On this basis, we extend the quasi-binary phase diagram of Al-Mg_(2)Si along deformation as the third dimension and construct an innovative defect phase diagram for the Al-Mg-Si-based system. To testify to the effect of deformation-mediated cyclic evolution of precipitation/precipitates on the optimum mechanical properties, peak-aging treatments were performed in samples of ST and 3-pass states. Based on the microscopic characterizations, a distinctive mechanism of peak-aging strengthening is proposed. Notably in the 3-pass ECAPed and peak-aged sample the dominant strengthening phases become the L precipitates that thrived from the segmented and spherical L phases, rather than β’’ precipitates in the solely peak-aged ST sample. Our work provides a feasible example for exploring the combined processing technique of multi-step deformation and thermal treatments, to optimize the mechanical properties.展开更多
Background:Pneumonia remains a critical global health challenge,manifesting as a severe respiratory infection caused by viruses,bacteria,and fungi.Early detection is paramount for effective treatment,potentially reduc...Background:Pneumonia remains a critical global health challenge,manifesting as a severe respiratory infection caused by viruses,bacteria,and fungi.Early detection is paramount for effective treatment,potentially reducing mortality rates and optimizing healthcare resource allocation.Despite the importance of chest X-ray diagnosis,image analysis presents significant challenges,particularly in regions with limited medical expertise.This study addresses these challenges by proposing a computer-aided diagnosis system leveraging targeted image preprocessing and optimized deep learning techniques.Methods:We systematically evaluated contrast limited adaptive histogram equalization with varying clip limits for preprocessing chest X-ray images,demonstrating its effectiveness in enhancing feature visibility for diagnostic accuracy.Employing a comprehensive dataset of 5,863 X-ray images(1,583 pneumonia-negative,4,280 pneumonia-positive)collected from multiple healthcare facilities,we conducted a comparative analysis of transfer learning with pre-trained models including ResNet50v2,VGG-19,and MobileNetV2.Statistical validation was performed through 5-fold cross-validation.Results:Our results show that the contrast limited adaptive histogram equalization-enhanced approach with ResNet50v2 achieves 93.40%accuracy,outperforming VGG-19(84.90%)and MobileNetV2(89.70%).Statistical validation confirms the significance of these improvements(P<0.01).The development and optimization resulted in a lightweight mobile application(74 KB)providing rapid diagnostic support(1-2 s response time).Conclusion:The proposed approach demonstrates practical applicability in resource-constrained settings,balancing diagnostic accuracy with deployment efficiency,and offers a viable solution for computer-aided pneumonia diagnosis in areas with limited medical expertise.展开更多
In this study,the interaction between deformation and precipitates during multiple equal channel angular pressing(ECAP)deformations and inter-pass aging combination and its effect on the mechanical properties of 7050 ...In this study,the interaction between deformation and precipitates during multiple equal channel angular pressing(ECAP)deformations and inter-pass aging combination and its effect on the mechanical properties of 7050 aluminum alloy are studied.The result show that ECAP induces numerous substructures and dislocations,effectively promoting the precipitation of theηʹphase exhibiting a bimodal structure during inter-pass aging.Following inter-pass aging and subsequent ECAP,the decrease in grain size(4.8μm)is together with the increase in dislocation density(1.24×10^(15) m^(−2))due to the pinning effect of the precipitated phase.Simultaneously,the dislocation motion causes the second phase particles to become even finer and more diffuse.The synergistic effects of precipitation strengthening,fine grain strengthening,and dislocation strengthening collectively enhance the high strength of aluminum alloys,with ultimate tensile strength and yield strength reaching approximately 610 and 565 MPa,respectively.Meanwhile,ductility remains largely unchanged,primarily due to coordinated grain boundary sliding and the uniform and fine dispersion of second phase particles.展开更多
On May 17,the World Telecommunication and Information Society Day(WTISD),ITU marks 160 years of technology for humanity with a light show at the Place des Nations in Geneva-also streamed live on ITU’s social media pl...On May 17,the World Telecommunication and Information Society Day(WTISD),ITU marks 160 years of technology for humanity with a light show at the Place des Nations in Geneva-also streamed live on ITU’s social media platforms.WTISD 2025 highlights the pressing need to advance digital gender equality,so that women and girls everywhere can also benefit from and contribute to digital transformation.展开更多
Early detection of Forest and Land Fires(FLF)is essential to prevent the rapid spread of fire as well as minimize environmental damage.However,accurate detection under real-world conditions,such as low light,haze,and ...Early detection of Forest and Land Fires(FLF)is essential to prevent the rapid spread of fire as well as minimize environmental damage.However,accurate detection under real-world conditions,such as low light,haze,and complex backgrounds,remains a challenge for computer vision systems.This study evaluates the impact of three image enhancement techniques—Histogram Equalization(HE),Contrast Limited Adaptive Histogram Equalization(CLAHE),and a hybrid method called DBST-LCM CLAHE—on the performance of the YOLOv11 object detection model in identifying fires and smoke.The D-Fire dataset,consisting of 21,527 annotated images captured under diverse environmental scenarios and illumination levels,was used to train and evaluate the model.Each enhancement method was applied to the dataset before training.Model performance was assessed using multiple metrics,including Precision,Recall,mean Average Precision at 50%IoU(mAP50),F1-score,and visual inspection through bounding box results.Experimental results show that all three enhancement techniques improved detection performance.HE yielded the highest mAP50 score of 0.771,along with a balanced precision of 0.784 and recall of 0.703,demonstrating strong generalization across different conditions.DBST-LCM CLAHE achieved the highest Precision score of 79%,effectively reducing false positives,particularly in scenes with dispersed smoke or complex textures.CLAHE,with slightly lower overall metrics,contributed to improved local feature detection.Each technique showed distinct advantages:HE enhanced global contrast;CLAHE improved local structure visibility;and DBST-LCM CLAHE provided an optimal balance through dynamic block sizing and local contrast preservation.These results underline the importance of selecting preprocessing methods according to detection priorities,such as minimizing false alarms or maximizing completeness.This research does not propose a new model architecture but rather benchmarks a recent lightweight detector,YOLOv11,combined with image enhancement strategies for practical deployment in FLF monitoring.The findings support the integration of preprocessing techniques to improve detection accuracy,offering a foundation for real-time FLF detection systems on edge devices or drones,particularly in regions like Indonesia.展开更多
It is of great significance to study the corrosion process of aluminum(Al)alloys fasteners in order to mitigate corrosion for their widespread applications.In this paper,a method for enhancing the corrosion resistance...It is of great significance to study the corrosion process of aluminum(Al)alloys fasteners in order to mitigate corrosion for their widespread applications.In this paper,a method for enhancing the corrosion resistance of Al alloy fasteners is proposed.7075 Al alloy parts with a fine-grained microstructure were prepared by pre-heat treatment(PHT),combined subsequent equal channel angular pressing(ECAP)and cold upsetting(CU).The corrosion behavior of the specimens was investigated by intergranular corrosion and electrochemical test.Microstructure investigations were carried out by field emission scanning electron microscopy,energy dispersive spectrometer and transmission electron microscopy.The relationship between microstructural evolution and corrosion resistance changes was also explored.The results show that both PHT and ECAP-CU significantly improved the corrosion resistance of the samples and modified the corrosion process.The open circuit potential,corrosion current density and corrosion rate of the alloy on electrochemical test were(-0.812±8.854)×10^(-5) V(vs.SCE),(6.379±0.025)×10^(-6) A/cm^(2) and 0.066 mm/year,respectively,and the intergranular corrosion depth was(557±8)μm.The main factor controlling the corrosion behavior was the microstructure evolution.After PHT,the disappearance of the dendritic structure and the dissolution of the nonequilibrium second phase eliminated the potential difference between the phases,reducing the free energy in the as cast state.When ECAP-CU was used after PHT,the grain refinement was accompanied by a high density of grain boundaries and dislocations,which led to the formation of a denser passivation film on the alloy surface,improving the corrosion resistance in an aggressive environment.展开更多
基金National Natural Science Foundation of China, No.41130748, No.41471143
文摘The urban-rural equalized development （URED） as a definite measure and operating model is beneficial to gradually eliminating the dual-track structure of urban-rural development, bridging the gap of urban-rural development, and creating harmonious urban-rural interactions. This paper aims to explore the status quo of URED in China at prefecture level, and to reveal the spatio-temporal patterns of URED and its differentiation regularity. The results show that： （1） China＇s URED level can be categorized into two parts, i.e., the eastern and the western, according to the ＂HU Huanyong Line＂, presenting a pattern of ＂east high and west low＂ and the URED level improves on the whole with the increase of distance from the line; （2） China＇s URED level can also be categorized into the northern and the southern parts according to ＂Kunlun-Qinling-Huaihe Line＂, presenting a pattern of ＂north high and south low＂, and the URED level reduces on the whole with the increase of distance from the line; （3） At the national level, China＇s URED has a significant trend of spatial agglomeration, the high and low URED regions tend to be adjacent, namely, the URED level presents obvious regional unbalance; （4） The five sub-dimension indicators of the URED level in the geographical space also reveal similar regional differentiation pattern, and in the aspect of space a decreasing trend is found in the URED level from the eastern （northern coast, eastern coast and southern coast）, the northeastern, the central （the middle reaches of the Yangtze River and the Yellow River） to the western （northwest and southwest）; and （5） China＇s URED at prefecture-level city can be divided into five types of differentiation areas. This study contributes to promoting the integrative cognition of the status quo of China＇s URED and can serve as a scientific ref- erence concerning the decision-making of coordinating urban-rural development and of pushing forward new-type urbanization strategy in China.
文摘Abstract There are many soft-rock roadway coal mines in China. The surrounding rocks of the high-stress soft-rock roadways in deep mine are especially difficult to be supported using the traditional supporting way. In this study, the south wing rail roadway on the second level of Yunjialing coal mine in China was used as an example to analyze the deformation and failure characteristics and influencing factors of roadway. On this basis, this study proposed the equalized yielding support idea which employs the yielding rings to realize the pressure equalization on the bolts and cables in the section. To achieve this purpose, the first bolt-mesh-cable equalizing pressure yielding support was integrated with the second grouting reinforcement. The results proved that the yield rings of the bolts and cables on the spandrel of the arched roadway firstly developed yielding deformation; then the deformation extended to the vault of the roadway; the bolts and cables achieved a yielding extreme value of 15 and 18 tonnes, respectively. The roadway surrounding rock tended to be stable at the 26th day after the maintenance. The equalizing pressure yielding supporting technology plays a moderate pressure-releasing and actively controlling role on the surrounding rocks in the soft-rock roadway with large deformation.
文摘We take the contribution of all valence electrons into consideration and propose a new valence electrons equilibration method to calculate the equalized electronegativity including molecular electronegativity, group electronegativity, and atomic charge. The ionization potential of alkanes and mono-substituted alkanes, the chemical shift of 1H NMR, and the gas phase proton affinity of aliphatic amines, alcohols, and ethers were estimated. All the expressions have good correlations. Moreover, the Sanderson method and Bratsch method were modified on the basis of the valence electrons equilibration theory. The modified Sanderson method and modified Bratsch method are more effective than their original methods to estimate these properties.
基金supported by the National Natural Science Foundation of China(No.62404098)the Natural Science Foundation of Jiangsu Province of China(No.BK20241196)the National Key Research and Development Program of China(Nos.2023YFB2806400,2021YFB2801902,and 2018YFB2201801)。
文摘In this Letter,we propose and experimentally demonstrate,to the best of our knowledge,a novel compact power-equalized multi-wavelength laser(MWL)source for optical I/O technology.This multi-wavelength distributed feedback(DFB)laser array is used to achieve simultaneous emission of multiple wavelengths with balanced output power and stable single-mode operation.The reconstruction equivalent chirp technique is used to design and fabricate theπ-phase shifted DFB laser array to achieve precise wavelength spacing.The power equalizers(PEs)are monolithically integrated in front of the laser unit to equalize the output power.The experimental results show that the wavelength spacing of the proposed eight-channel MWL is 100 G±4.38 G,and the maximum deviation of the intensity(MDOI)is 1.00 dB under a 25℃working environment.Compared with the traditional MWL structure,the wavelength spacing error is reduced from 0.32 to 0.035 nm,and the MODI is reduced from 3.8 to 1.0 dB.The output power exceeds 25 mW when the current injected into the semiconductor optical amplifier(SOA)is 150 mA.Besides,the relative intensity noise(RIN)of all wavelengths is below-138 dB/Hz,and clear 25 Gb/s non-return-to-zero(NRZ)eye diagrams are obtained for the eight wavelengths with the external lithium-niobate Mach-Zehnder modulator.The superior performance of the proposed MWL makes it a promising method for low-bit-error optical I/O links and high-density chip interconnection systems.
文摘The ionization potential of organic homologs can be expressed as I_p=(∑X_i)/(a+bn).Here, X_i is the electronegativity(the average energy of valence electrons in a ground-state free atom)of the ith atom in an organic homologous molecule;n,the number of repeating units in the molecule;and(a+bn),the electron moving range in the molecule orbit.The results of linear regression analysis show that the correlation coefficients r are all 'excellent'(r>0.990)for the 146 sets of photo electron spectroscopy data of 42 organic homologous series.
基金supported by National Key R&D Program of China No.2022YFB2803401.
文摘In DSP-based SerDes application,it is essential for AFE to implement a pre-ADC equalization to provide a better sig-nal for ADC and DSP.To meet the various equalization requirements of different channel and transmitter configurations,this paper presents a 112 Gbps DSP-Based PAM4 SerDes receiver with a wide band equalization tuning AFE.The AFE is realized by implementing source degeneration transconductance,feedforward high-pass branch and inductive feedback peaking TIA.The AFE offers a flexible equalization gain tuning of up to 17.5 dB at Nyquist frequency without affecting the DC gain.With the pro-posed AFE,the receiver demonstrates eye opening after digital FIR equalization and achieves 6×10^(-9) BER with a 29.6 dB inser-tion loss channel.
文摘On the evening of May 3Oth,the parallel forum"Equality and Inclusiveness&Harmonious Coexistence:Multi-dimensional Narratives of Civilisations from Writers'Perspective",as part of the 4th Dialogue on Exchanges and Mutual Learning among Civilisations,was held in Dunhuang.The forum was organised by the China Writers Association and co-organised by China National Publications Import&Export(Group)Corporation.
文摘A new cyclic prefix(CP)-based nonoverlapping FBMC-QAM(CP-NO-FBMC-QAM)system with two prototype filters is proposed in this paper,which satisfies complex orthogonality conditions and good frequency energy confinement at the same time.We analyze its inter-carrier interference/inter-symbol interference(ICI/ISI)over multipath channels.Owing to the additional CP,the ISI of received symbols over multipath channels is eliminated in the proposed system,and the resulting improvement in the signal-to-interference ratio(SIR)performance is evaluated by theoretical analysis.Moreover,for the ICI caused by multipath propagation in received symbols,we develop a method that eliminates the ICI by frequency-domain channel estimation and equalization before the receiver filtering process.The proposed CP-NO-FBMC-QAM system and ICI cancellation method(ICICM)are validated by comparisons of implementation complexity,power spectral density(PSD),bit error rate(BER)and channel estimation performance with conventional CP-based orthogonal frequency division multiplexing(CP-OFDM)and FBMC-QAM systems.
基金This paper is a phased research outcome of the 2023 Beijing International Studies University Regional and Country Studies Special Research Project titled“Reading Promotion in Nordic Public Libraries and Its Implications for China’s National Reading Development”(Project No.QYGB23A003).
文摘Under the background of accelerated global cultural exchange and information dissemination,reading has become a crucial component of public cultural services.Public libraries in Nordic countries(Denmark,Sweden,Norway,Finland,Iceland)stand out by adhering to the core philosophy of“universal sharing and equal reading”,integrating reading promotion into national strategies,and constructing extensive service networks through sound legal guarantees and adequate financial support.This study identifies four key strategies for universality and equality in Nordic public libraries:covering all age groups,eliminating group differences,integrating digital and physical resources,and ensuring the right to read through legislative,financial,and other institutional support.These provide a reference for global public cultural services.
基金supported by the National Key R&D Program of China(No.2022YFB3205101)NSAF(No.U2230116)。
文摘To improve image quality under low illumination conditions,a novel low-light image enhancement method is proposed in this paper based on multi-illumination estimation and multi-scale fusion(MIMS).Firstly,the illumination is processed by contrast-limited adaptive histogram equalization(CLAHE),adaptive complementary gamma function(ACG),and adaptive detail preserving S-curve(ADPS),respectively,to obtain three components.Then,the fusion-relevant features,exposure,and color contrast are selected as the weight maps.Subsequently,these components and weight maps are fused through multi-scale to generate enhanced illumination.Finally,the enhanced images are obtained by multiplying the enhanced illumination and reflectance.Compared with existing approaches,this proposed method achieves an average increase of 0.81%and 2.89%in the structural similarity index measurement(SSIM)and peak signal-to-noise ratio(PSNR),and a decrease of 6.17%and 32.61%in the natural image quality evaluator(NIQE)and gradient magnitude similarity deviation(GMSD),respectively.
文摘THE world should be celebrating the creation of the United Nations(UN)80 years ago.However,its very existence is threatened.China recognizes the UN as the core of the international system.The UN Charter is a legal treaty under which national governments freely agree to uphold values and principles of behaviour.As a manifestation of the principle of“the sovereign equality of members,”each has an equal vote in the General Assembly.
基金financial support of the National Natural Science Foundation of China(Nos.52001142 and 51975263).
文摘Zn–Ag alloys are highly promising materials for fabricating biodegradable orthopedic implants.Nonetheless,they suffer from inferior strength.A Zn–2.5Ag alloy was alloyed with different contents of Mg(0.08,0.5,and 1 wt.%)and then processed by equal channel angular pressing.Tensile tests and microstructure observation were conducted to investigate the impact of Mg addition on the microstructure and mechanical properties of Zn–2.5Ag alloy.Zn–2.5Ag alloy exhibits an ultrahigh elongation(EL)of 120.4%but a poor yield strength(YS)of 90.1 MPa,because of phase boundary sliding(PBS).Mg addition inhibits PBS and thus dramatically enhances YS but lowers EL.Specifically,YS of Zn–2.5Ag alloys containing Mg of 0.08%,0.5%,and 1%is 257.0,291.8,and 322.6 MPa,respectively.The alloys with 0.08%and 0.5%Mg possess an EL of around 30%,while the alloy with 1%Mg has an EL of only 11.0%.YS and EL of Zn–2.5Ag–0.5Mg alloy surpass that needed by orthopedic implants by 45.9%and 106.0%,respectively.Grain refinement strengthening is the main contributor to high strength.It is speculated that deformation twinning suppression and<c+a>pyramidal slip activation contribute to good ductility.
基金supported by the National Natural Science Foundation of China(No.51904036)the Hunan Provincial Key Research and Development Program(No.2023GK2049).
文摘The effect of rotational-die equal channel angular pressing(RD-ECAP)temperature and deformation route on the microstructure and mechanical properties of pre-extruded Mg-5Gd-3Y-1Zn-0.5Zr(wt%)alloys were investigated.The results indicate that the RD-ECAP updates both theα-Mg texture and long-period stack-ing ordered(LPSO)arrangement in the pre-extruded alloy,while theα-Mg texture is more sensitive to the change of deformation route.The LPSO streamlines modify the anisotropy of mechanical properties of the ECAP alloys via exerting different reinforcing effects and modifying the crack propagation.The lower ECAP temperature of 350℃ rather than 400℃ promotes dynamic precipitation which deteriorates the following ageing-hardening response but conduces to refining theα-Mg grains and preventing a sharp drop in elongation after peak ageing.The 350A peak-aged alloy exhibits the optimal mechanical proper-ties with the average tensile yield strength(TYS)of 311 MPa(S_(TYS)=3.7,S indicates standard deviation)and elongation of 7.6%(S_(EL)=0.7).Its higher strength should mainly be attributed to the finer grain size,and its quasi-isotropic performance should be inherited from the ECAP state induced by the rational arrangement of LPSO phases.
文摘The Global Leaders’Meeting on Women was held in Beijing,the capital of China,on 13-14 October.South African Minister in the Presidency for Women,Youth and Persons with Disabilities Sindisiwe Chikunga,attended the event.ChinAfrica spoke with her in an exclusive interview about the messages she brought to the meeting,South Africa’s progress in women’s empowerment,how the G20 presidency can contribute to this cause,and China’s role.An edited excerpt of the interview follows.
基金supported by the National Natural Science Foundation of China(Grant Nos.U22A20187,52171007,52371111,and 52371177).
文摘Precipitation via thermal treatments is among the most effective approaches to strengthening and is widely applied in the Al industry. Thermal treatments combined with deformation are capable of finely regulating the process of precipitation and distribution of precipitates. Deformation-induced defects exert significant impacts on the precipitation and already present precipitates, which however is often overlooked. In this study, the interactions between deformation and precipitation/precipitates, and their impacts on mechanical properties were systematically investigated in the solution-treated (ST) Al-0.61Mg-1.17Si-0.5Cu (wt.%), processed by multi-pass equal channel angular pressing (ECAP) and thermal treatments. Novel deformation-mediated cyclic evolution of precipitates is discovered: ST→ (1,2 passes: deformation induced precipitation) Guinier Preston (GP) zones→ (An250/30) Q’ and L phases→ (3-pass: deformation induced fragmentation/resolution) spherical precipitates→ (4-pass: deformation induced further fragmentation/resolution) GP zones. On this basis, we extend the quasi-binary phase diagram of Al-Mg_(2)Si along deformation as the third dimension and construct an innovative defect phase diagram for the Al-Mg-Si-based system. To testify to the effect of deformation-mediated cyclic evolution of precipitation/precipitates on the optimum mechanical properties, peak-aging treatments were performed in samples of ST and 3-pass states. Based on the microscopic characterizations, a distinctive mechanism of peak-aging strengthening is proposed. Notably in the 3-pass ECAPed and peak-aged sample the dominant strengthening phases become the L precipitates that thrived from the segmented and spherical L phases, rather than β’’ precipitates in the solely peak-aged ST sample. Our work provides a feasible example for exploring the combined processing technique of multi-step deformation and thermal treatments, to optimize the mechanical properties.
文摘Background:Pneumonia remains a critical global health challenge,manifesting as a severe respiratory infection caused by viruses,bacteria,and fungi.Early detection is paramount for effective treatment,potentially reducing mortality rates and optimizing healthcare resource allocation.Despite the importance of chest X-ray diagnosis,image analysis presents significant challenges,particularly in regions with limited medical expertise.This study addresses these challenges by proposing a computer-aided diagnosis system leveraging targeted image preprocessing and optimized deep learning techniques.Methods:We systematically evaluated contrast limited adaptive histogram equalization with varying clip limits for preprocessing chest X-ray images,demonstrating its effectiveness in enhancing feature visibility for diagnostic accuracy.Employing a comprehensive dataset of 5,863 X-ray images(1,583 pneumonia-negative,4,280 pneumonia-positive)collected from multiple healthcare facilities,we conducted a comparative analysis of transfer learning with pre-trained models including ResNet50v2,VGG-19,and MobileNetV2.Statistical validation was performed through 5-fold cross-validation.Results:Our results show that the contrast limited adaptive histogram equalization-enhanced approach with ResNet50v2 achieves 93.40%accuracy,outperforming VGG-19(84.90%)and MobileNetV2(89.70%).Statistical validation confirms the significance of these improvements(P<0.01).The development and optimization resulted in a lightweight mobile application(74 KB)providing rapid diagnostic support(1-2 s response time).Conclusion:The proposed approach demonstrates practical applicability in resource-constrained settings,balancing diagnostic accuracy with deployment efficiency,and offers a viable solution for computer-aided pneumonia diagnosis in areas with limited medical expertise.
基金Project(52275350)supported by the National Natural Science Foundation of ChinaProject(0301006)supported by the International Cooperative Scientific Research Platform of SUES,China。
文摘In this study,the interaction between deformation and precipitates during multiple equal channel angular pressing(ECAP)deformations and inter-pass aging combination and its effect on the mechanical properties of 7050 aluminum alloy are studied.The result show that ECAP induces numerous substructures and dislocations,effectively promoting the precipitation of theηʹphase exhibiting a bimodal structure during inter-pass aging.Following inter-pass aging and subsequent ECAP,the decrease in grain size(4.8μm)is together with the increase in dislocation density(1.24×10^(15) m^(−2))due to the pinning effect of the precipitated phase.Simultaneously,the dislocation motion causes the second phase particles to become even finer and more diffuse.The synergistic effects of precipitation strengthening,fine grain strengthening,and dislocation strengthening collectively enhance the high strength of aluminum alloys,with ultimate tensile strength and yield strength reaching approximately 610 and 565 MPa,respectively.Meanwhile,ductility remains largely unchanged,primarily due to coordinated grain boundary sliding and the uniform and fine dispersion of second phase particles.
文摘On May 17,the World Telecommunication and Information Society Day(WTISD),ITU marks 160 years of technology for humanity with a light show at the Place des Nations in Geneva-also streamed live on ITU’s social media platforms.WTISD 2025 highlights the pressing need to advance digital gender equality,so that women and girls everywhere can also benefit from and contribute to digital transformation.
基金funded by the Directorate of Research,Technology,and Community Service,Ministry of Higher Education,Science,and Technology of the Republic of Indonesia the Regular Fundamental Research scheme,with grant numbers 001/LL6/PL/AL.04/2025,011/SPK-PFR/RIK/05/2025.
文摘Early detection of Forest and Land Fires(FLF)is essential to prevent the rapid spread of fire as well as minimize environmental damage.However,accurate detection under real-world conditions,such as low light,haze,and complex backgrounds,remains a challenge for computer vision systems.This study evaluates the impact of three image enhancement techniques—Histogram Equalization(HE),Contrast Limited Adaptive Histogram Equalization(CLAHE),and a hybrid method called DBST-LCM CLAHE—on the performance of the YOLOv11 object detection model in identifying fires and smoke.The D-Fire dataset,consisting of 21,527 annotated images captured under diverse environmental scenarios and illumination levels,was used to train and evaluate the model.Each enhancement method was applied to the dataset before training.Model performance was assessed using multiple metrics,including Precision,Recall,mean Average Precision at 50%IoU(mAP50),F1-score,and visual inspection through bounding box results.Experimental results show that all three enhancement techniques improved detection performance.HE yielded the highest mAP50 score of 0.771,along with a balanced precision of 0.784 and recall of 0.703,demonstrating strong generalization across different conditions.DBST-LCM CLAHE achieved the highest Precision score of 79%,effectively reducing false positives,particularly in scenes with dispersed smoke or complex textures.CLAHE,with slightly lower overall metrics,contributed to improved local feature detection.Each technique showed distinct advantages:HE enhanced global contrast;CLAHE improved local structure visibility;and DBST-LCM CLAHE provided an optimal balance through dynamic block sizing and local contrast preservation.These results underline the importance of selecting preprocessing methods according to detection priorities,such as minimizing false alarms or maximizing completeness.This research does not propose a new model architecture but rather benchmarks a recent lightweight detector,YOLOv11,combined with image enhancement strategies for practical deployment in FLF monitoring.The findings support the integration of preprocessing techniques to improve detection accuracy,offering a foundation for real-time FLF detection systems on edge devices or drones,particularly in regions like Indonesia.
基金Project(52275350)supported by the National Natural Science Foundation of ChinaProject(0301006)supported by International Cooperative Scientific Research Platform of SUES,China。
文摘It is of great significance to study the corrosion process of aluminum(Al)alloys fasteners in order to mitigate corrosion for their widespread applications.In this paper,a method for enhancing the corrosion resistance of Al alloy fasteners is proposed.7075 Al alloy parts with a fine-grained microstructure were prepared by pre-heat treatment(PHT),combined subsequent equal channel angular pressing(ECAP)and cold upsetting(CU).The corrosion behavior of the specimens was investigated by intergranular corrosion and electrochemical test.Microstructure investigations were carried out by field emission scanning electron microscopy,energy dispersive spectrometer and transmission electron microscopy.The relationship between microstructural evolution and corrosion resistance changes was also explored.The results show that both PHT and ECAP-CU significantly improved the corrosion resistance of the samples and modified the corrosion process.The open circuit potential,corrosion current density and corrosion rate of the alloy on electrochemical test were(-0.812±8.854)×10^(-5) V(vs.SCE),(6.379±0.025)×10^(-6) A/cm^(2) and 0.066 mm/year,respectively,and the intergranular corrosion depth was(557±8)μm.The main factor controlling the corrosion behavior was the microstructure evolution.After PHT,the disappearance of the dendritic structure and the dissolution of the nonequilibrium second phase eliminated the potential difference between the phases,reducing the free energy in the as cast state.When ECAP-CU was used after PHT,the grain refinement was accompanied by a high density of grain boundaries and dislocations,which led to the formation of a denser passivation film on the alloy surface,improving the corrosion resistance in an aggressive environment.
