Dielectric anisotropy in liquid crystal mixtures with nematic and smectic phases

The modulation of dielectric anisotropy(△ε)is pivotal for elucidating molecular interactions and directing the alignment of liquid crystals.In this study,we combine liquid crystals with opposing dielectric anisotropies to explore the impact of varying concentrations on their properties.We report the sign-reversal of△εin both the nematic and smectic A phases of these mixed liquid crystals,alongside a dual-frequency behaviour across a broad temperature spectrum.Our research further quantifies the influence of mixture ratios under various temperatures and electric field frequencies.This exploration may pave the way for the discovery of new physical phenomena.

Research on the Construction of Group Elderly Care Service Platform Based on IoT Technology

Internet of Things(IoT)technology is widely used in various fields,and its application in elderly care services has been highlighted in recent years.This study aims to explore how IoT technology can improve the efficiency of group-based elderly care services.The concept,characteristics,and current application status of IoT technology in elderly care services were introduced.Secondly,the characteristics and needs of group elderly care services were analyzed,including advantages and challenges,as well as the expectations and needs of the elderly for elderly care services.The evaluation methods and future development directions of IoT technology in improving the efficiency of group elderly care services were discussed,including data collection and analysis methods,selection and measurement of efficiency evaluation indicators,challenges,and development directions.

Construction and Application of a Quality Evaluation System for Group Elderly Care Services Based on the Internet of Things

With the continuous intensification of global aging,the issue of elderly care has become an increasingly prominent social problem.The Internet of Things(IoT)technology,as an emerging field,holds broad application prospects.This article focuses on the application of IoT technology in group elderly care services and constructs a quality evaluation system for these services based on IoT technology.Through the analysis of practical application cases,the advantages and challenges of IoT technology in group elderly care services have been examined,confirming the feasibility and effectiveness of the evaluation system.

Research and Application of Recycled Concrete Technology in Prefabricated Buildings

The utilization of waste concrete as a raw material for recycled concrete in the domain of prefabricated components is garnering greater interest.This paper delineates and examines the concept,categorization,methodologies of preparation,applicable sectors,and evaluative metrics of recycled concrete technology,highlighting its prospective benefits.Nonetheless,for the successful integration of recycled concrete technology into prefabricated component applications,it is imperative to systematically enhance its physical,mechanical,and attributes,as well as its environmental efficacy.Moreover,to foster the continued advancement of recycled concrete technology,innovative initiatives,standardization,educational programs,demonstration projects,and collaborative efforts are crucial to promote broader adoption and realize improved outcomes within the realm of prefabricated components.In conclusion,recycled concrete technology is poised to play a pivotal role in prefabricated construction,offering robust support for propelling the construction industry towards a sustainable future.

Surface lattice resonance of circular nano-array integrated on optical fiber tips

As metallic nanoparticles are arranged to form a 2D periodic nano-array,the coupling of the localized surface plasmonic resonance(LSPR)results in the well-known phenomenon of surface lattice resonances(SLRs).We theoretically investigate the SLR effect of the circular nano-array fabricated on the fiber tips.The difference between the 2D periodic and circular periodic arrays results in different resonant characteristics.For both structures,the resonant peaks due to the SLRs shift continuously as the array structures are adjusted.For some specific arrangements,the circular nano-array may generate a single sharp resonant peak with extremely high enhancement,which originates from the collective coupling of the whole array.More interestingly,the spatial pattern of the vector near-field corresponding to the sharp peak is independent of the polarization state of the incidence,facilitating its excitation and regulation.This finding may be helpful for designing multifunctional all-fiber devices.

Calculation and Analysis of Near-Field Head-Related Transfer Functions from a Simplified Head-Neck-Torso Model

To evaluate the overall effect of the neck and torso on the head-related transfer function(HRTF),a simplified head-neck-torso(HNT)model,which consists of a spherical head,spherical torso and cylindrical neck,is proposed and the corresponding HRTFs are calculated using the boundary element method(BEM).The results indicate that the HRTF magnitudes for the HNT model are different from those of the existing spherical head-and-torso model(HAT)above 0.5 kHz,especially in the near-field and contralateral region.The discrepancy in the HRTF magnitudes leads to a discrepancy in the interaural level differences(ILDs)for the HNT and HAT models,which reaches a level of-l0dB at source distance of 0.2m.As the source distance increases,the discrepancy in the results of the HNT and HAT models reduces.Measurement on practical HNT and HAT models validates the analysis.Therefore,the neck influences near-field HRTFs and should be included in the near-field HRTF calculation.

Ultra-wideband direct-sequence design approach for multiple narrowb and interference suppression

A novel direct sequence （DS） design method for suppressing the narrowband interference in DS spread spectrum ultra-wideband receivers is proposed. The method has low computational complexity and can be easily implemented in practical systems. Simulation results prove that the proposed method is effective to suppress the narrowband interference. Therefore, the integrity of both the ultra-wide bandwidth and the narrowband systems can be highly enhanced.

Empirical Analysis on Relationship between Apple Futures and Spot Prices in China

Taking a total of 903 apple futures data from Zhengzhou Futures Exchange as research samples, and through unit root test, cointegration test, error correction, Granger causality test and variance decomposition with the aid of Eviews 8.0, this paper made an empirical analysis on the relationship between Zhengzhou apple futures market and Chinese apple website(pingguo7.cn) spot market price. It concluded that the main continuity of apple futures has an absolute advantage over the reference value of the futures index, and apple market participants can achieve hedging through the futures and spot market.

Effects of Aerobic Exercise Combined with Resistance Training on Patients with Myocardial Ischemia Caused by Coronary Heart Disease

Objective:To explore the clinical effect of long-term aerobic exercise combined with resistance training in patients with myocardial ischemia caused by coronary heart disease and its influence on cardiac function, exercise endurance and quality of life. Methods:100 patients with myocardial ischemia caused by coronary heart disease from January 2017 to January 2019 were randomly divided into control group (n = 50 cases) and observation group (n = 50 cases). The control group was given resistance training, while the observation group was combined with long-term aerobic exercise on the basis of the control group. The two groups were treated for 3 months. The cardiac function, exercise endurance and quality of life were compared between the two groups. Results:The levels of IVST (8.20+1.32) mm, LVDD (46.43+4.13) mm and LVSD (32.59+3.15) mm in the observation group were lower than those in the control group at 3 months after treatment. The level of LVEF (67.49+5.77)% in the observation group was higher than that in the control group at 3 months after treatment. The difference between the two groups was significant (P<0.05). The ET (55.42+2.9) in the observation group was higher than that in the control group (P<0.05). 2) The levels of ng/L and TXB2 (93.23 + 6.26) ng/L were significantly lower than those of the control group, and the difference between the two groups was statistically significant (P<0.05). The 6-minute walking distance (561.25 +43.64) m and the quality of life score (95.31 +6.39) in the observation group were higher than those in the control group 3 months after treatment, and the difference between the two groups was statistically significant (P<0.05). Conclusions:Long-term aerobic exercise combined with resistance training can improve cardiac function, exercise tolerance and quality of life in patients with myocardial ischemia caused by coronary heart disease, which is worthy of popularization and application.

Clinical effect of long term aerobic exercise combined with Ginkgo Biloba Leaves Extract Tablets in the treatment of arteriosclerosis

Objective: To investigate the clinical effect of long-term aerobic exercise combined with Ginkgo biloba leaves on atherosclerosis. Methods: 104 patients with carotid atherosclerosis admitted to the Affiliated Hospital of Xi'an Medical College from January 2016 to January 2018 were randomly divided into exercise training group and control group, 52 cases in each group. The control group was treated with Ginkgo biloba leaves, and the exercise training group was treated with long-term aerobic exercise combined with Ginkgo biloba leaves. Both groups were treated for 6 months. The therapeutic effects of the two groups were compared. Results: After treatment, the levels of TC, TG and LDL-C in the two groups were lower than those before treatment, and the levels of HDL-C were higher than those before treatment (P<0.05);after treatment, the levels of TC, TG and LDL-C in the exercise training group were lower than those in the control group, and the levels of HDL-C were higher than those in the control group, with significant difference between the two groups (P<0.05). After treatment, the CIM T and plaque area of the two groups were smaller than those before treatment, and the blood velocity of cerebral artery was higher than that before treatment (P<0.05);after treatment, the CIM T and plaque area of the exercise training group were smaller than those of the control group, and the blood velocity of left middle cerebral artery, right middle cerebral artery and basilar artery were higher than those of the control group. The difference was statistically significant (P<0.05). Conclusion: Long-term aerobic exercise combined with Ginkgo biloba leaf therapy can effectively reduce the blood lipid concentration in patients with carotid atherosclerosis and improve cerebral blood supply.

Application effect of exercise rehabilitation therapy in elderly patients with chronic heart failure

Objective:To investigate the effects of rehabilitation exercise therapy on 6-minute walking distance (6 minute walk distance, 6MWD), brain natriuretic titanium (Brain natriuretic peptide, BNP) and (Minnesota heart failure quality of life scale, MLHFQ score in elderly patients with chronic heart failure (CHF).Methods: Choose xi'an medical college affiliated hospital heart treated with 96 cases of elderly patients with chronic heart failure (from January 2016 to January 2018), according to random number table method, divide the patients as control group and observation group 48 cases/group, control group to implement regular heart failure treatment, the observation group in the control group, the implementation of rehabilitation exercise therapy on the basis of comparing the clinical curative effect of two groups of indicators, heart colour to exceed, 6 MWDS, BNP levels, plate movement, MLHFQ score. Results: (1) compared with the control group, the total effective rate of the observation group was higher than that of the control group (P<0.05). (2). After treatment, the left ventricular end-diastolic diameter (Left ventricular end diastolic diameter, LVEDD) and the left ventricular end-systolic diameter (Left ventricular end systolic diameter, LVESD), BNP) in the observation group were higher than those in the control group. All the MLHFQ scores were lower than those in the control group (P<0.05). The left ventricular ejection fraction (Left ventricular ejection fraction, LVEF), stroke output (Stroke volume, SV) and treadmill metabolic equivalent (Metabolic equivalent, METs) were higher than those in the control group (P<0.05). The treadmill exercise time was longer than that in the control group (P<0.05), and its 6MWD was higher than that in the control group (P<0.05).Conclusion: Rehabilitation exercise therapy in elderly patients with chronic heart failure can effectively improve the cardiac function, enhance their exercise endurance and energy metabolism level, and improve the clinical efficacy and quality of life.

CSI-based passive intrusion detection bound estimation in indoor NLoS scenario

Passive intrusion detection is important for many indoor safety applications.By utilizing widespread WiFi infrastructures,channel state information(CSI)based intrusion detection methods have attractive advantages such as low cost,non-line-of-sight(NLoS)support,and privacy protection.However,existing CSI-based methods lack in-depth and intensive analysis of intrusion detection bound.To the best of our knowledge,this is the first work that precisely characterizes and models CSI-based intrusion detection bound in typical indoor NLoS scenario.A bound is defined as an intruder’s farthest position from the transmitter during intrusion detection.To derive a model for the bound,we first derived an intrusion-disturbed NLoS channel model by analyzing the influence of human intrusion on the NLoS wireless channel.Subsequently,based on the channel model,we further derived an intrusion detection bound model.Based on the derived bound model,we proposed a practical system to estimate the real intrusion detection bound.Extensive experiments were conducted based on practical systems.The experimental and simulation results verified and demonstrated the effectiveness of the derived bound model.Our work not only reveals the fundamental performance limit of the basic intrusion detection method in an indoor NLoS scenario,but also provides a valuable reference for bound estimation for other fine-grained wireless sensing applications.

Design of Customer Satisfaction Measurement Index System of EMS Service

This paper discusses the design of a customer satisfaction measurement index system of erpress mail service. It presents objectives and principles of the design based on hierarchical structures. We have devised a diagram for modeling customer satisfaction, and a detailed analysis of customer satisfaction is conducted. This paper presents our customer satisfaction model and analysis results.

The review of RFID applications in global postal and courier services

On the basis of several practical applications in many countries, this article reviews the potential market scale of radio frequency identification （RFID） and its applications in global postal and courier services through studies and analyses. It gives some suggestions and options in the development of RFID and its application in postal and courier services.

The Review of China Post's Informationizing Constructing

The article briefly introduces the three stages that China Post experienced and the circumstances of the fundamental network construction, focusing on introducing the three sorts of services based on postal comprehensive computer network＇s applicable software system ： postal financial service ; traditional service electrified ; electronic postal service. Finally the thinking for future China Post＇s informationizing constructing is put forward.

Enhanced second-harmonic generation of asymmetric Au@CdSe heterorods

The plasmon-enhanced second-harmonic generation(SHG)of Au nanorods(NRs),Au-Ag NRs,and asymmetric Au@CdSe heterorods are comparatively investigated.The Au@CdSe tip-and side-heterorods are synthesized by precisely controlling the concentration of Cd2+precursor,and the plasmon resonances can be well tuned simultaneously.The SHG of asymmetric Au@CdSe heterorods has been greatly enhanced with up to 617.7-fold enhancement compared with the Au NRs because of the asymmetric morphology and local field enhancement.Moreover,the harmonic energy transfer induced by the local interband transition of Au has also been demonstrated by the excitation-wavelengthdependent SHG in the Au NRs and Au@CdSe side-heterorods,while it is negligible in the Au-Ag NRs and Au@CdSe tipheterorods because of the presence of Ag.The plasmon-enhanced SHG of asymmetric Au@CdSe heterorods enables potential applications ranging from sensing to biological spectroscopy.

Organic room-temperature phosphorescent polymers for efficient X-ray scintillation and imaging

Materials that exhibit visible luminescence upon X-ray irradiation show great potential in the medical and industrial fields.Pure organic materials have recently emerged as promising scintillators for X-ray detection and radiography,due to their diversified design,low cost,and facile preparation.However,recent progress in efficient radioluminescence has mainly focused on small molecules,which are inevitably associated with processability and repeatability issues.Here,a concise strategy is proposed to prepare radioluminescent polymers that exhibit multiple emission colors from blue to yellow with high brightness in an amorphous state by the radical copolymerization of negatively charged polyacrylic acid and different positively charged quaternary phosphonium salts.One of the obtained polymers exhibits excellent photostability under a high X-ray irradiation dosage of 27.35 Gy and has a detection limit of 149 nGy s^(−1).This performance is superior to that of conventional anthracene-based scintillators.Furthermore,by simply drop-casting a polymer methanol solution on a quartz plate,a transparent scintillator screen was successfully fabricated for X-ray imaging with a resolution of 8.7 line pairs mm^(−1).The pure organic phosphorescent polymers with a highly efficient radioluminescence were demonstrated for the first time,and the strategy reported herein offers a promising pathway to expand the application range of amorphous organic scintillators.

Birefringence-Managed Normal-Dispersion Fiber Laser Delivering Energy-Tunable Chirp-Free Solitons

Chirp-free solitons have been mainly achieved with anomalous-dispersion fiber lasers by the balance of dispersive and nonlinear effects,and the single-pulse energy is constrained within a relatively small range.Here,we report a class of chirp-free pulse in normal-dispersion erbium-doped fiber lasers,termed birefringence-managed soliton,in which the birefringence-related phasematching effect dominates the soliton evolution.Controllable harmonic mode locking from 5 order to 85 order is obtained at the same pump level of~10 mW with soliton energy fully tunable beyond ten times,which indicates a new birefringencerelated soliton energy law,which fundamentally differs from the conventional soliton energy theorem.The unique transformation behavior between birefringence-managed solitons and dissipative solitons is directly visualized via the singleshot spectroscopy.The results demonstrate a novel approach of engineering fiber birefringence to create energy-tunable chirpfree solitons in normal-dispersion regime and open new research directions in fields of optical solitons,ultrafast lasers,and theirapplications.

On interest-rate risk management of postal savings bureau

This article analyzes interest-rate risks faced by the postal savings bureau （PSB） based on the complete balance sheet. It presents the extended gap model and the extended duration gap model to measure the interest-rate risk, and discusses the inner balance-sheet strategies and the off-balance-sheet strategies to manage the interest-rate risks.

The Application of the Theory of the Price Elasticity of Demand to the EMS Management

Express Mail Service (EMS) is the most competitive one of the post services. Price competition is the core of market competition and so for EMS. In this paper, we calculate the coefficient of demand elasticity and then put forward the price strategy for EMS to increase its competitive power.