Reference information time delay estimation and compensation in transfer alignment

To reduce the error in transfer alignment caused by reference information delay,a time delay estimation method is developed based on least-squares curve fitting of the angular rate integration.First,the gyro sensor measurements of the main strapdown inertial navigation system（M-SINS） and the slave strapdown inertial navigation system（S-SINS） are recorded for a few seconds and the integration of the data is calculated.Then,the possible maximum range of the delay value is defined and the points of the curve at different intervals are moved.The square of the differences between the corresponding points are calculated.Finally,the delay estimation can be acquired by the least-squares curve fitting of the M-SINS and the S-SINS.A delay compensation method by local data shifting is also presented.The simulation results demonstrate the effectiveness of delay estimation and indicate that the estimation accuracy is independent of the delay value.And the local data shifting compensation method can effectively reduce the errors of the transfer alignment caused by the reference information delay.

Delay Effect on Coherent Transfer of Optical Frequency Based on a Triple-Pass Scheme

We demonstrate a triple-pass scheme for coherent transfer of optical frequency and the delay effect on the fiber phase noise compensation. It is theoretically proved that the delay effect consists of both fiber delay and servo delay. The delay effect confines the servo bandwidth within 1/8 and induces a residual fiber phase noise after noise compensation. For a 25-km-long fiber, the servo bandwidth is found to be around 1 k Hz, and the fiber phase noise is suppressed approaching to the theoretical limitation. The triple-pass scheme enables the simultaneous transfer of optical frequency to multiple remote users. The performance of noise compensator in the triple-pass scheme can achieve a similar level result compared with that in the double-pass scheme.

Routing in Delay Tolerant Networks (DTN)<br>—Improved Routing with MaxProp and the Model of “Transfer by Delegation” (Custody Transfer)

In this paper, we address the problem of routing in delay tolerant networks (DTN). In such networks there is no guarantee of finding a complete communication path connecting the source and destination at any time, especially when the destination is not in the same region as the source, which makes traditional routing protocols inefficient in that transmission of the messages between nodes. We propose to combine the routing protocol MaxProp and the model of “transfer by delegation” (custody transfer) to improve the routing in DTN networks and to exploit nodes as common carriers of messages between the network partitioned. To implement this approach and assess those improvements and changes we developed a DTN simulator. Simulation examples are illustrated in the article.

Effect of Adding a Delayed Blastocyst to a Good Quality One during Embryo Transfer on ICSI Cycle Outcomes

Objectives: Study the effect of adding a delayed blastocyst to a transferred good quality one on ICSI cycle outcomes. Study design: Prospective cohort study. Participants/materials, setting, methods: 90 infertile patients aged from 20 - 35 years due to mild male factor, unexplained infertility or tubal factor. Patients with PCOS, endometriosis, RIF, poor responder and azoospermia were excluded. Setting: Duration 6 months from October 2019 to April 2020 in a private IVF center in Egypt. 30 cases were subjected to elective single embryo transfer and the other 60 with two embryo transfers, one good quality and another poor quality blastocyst. Results: (clinical pregnancy rate) was comparable between the two groups, being 47.7% and 36.7% in SET and DET groups respectively (p = 0.361). Miscarriage and ectopic pregnancy rate were observed in 10% of the cases pregnant after SET (group I) and in only 6.7% of the cases pregnant after DET (group II) denoting no significant statistical difference between the two groups. The highest incidence was missed miscarriages in the two groups and ectopic pregnancy was observed only in one case in group II (DET). Twin pregnancy occurred in 22% of pregnant females in the second group. Late pregnancy complications in the form of preterm labour, premature rupture of membrane and preeclampsia occurred mainly in pregnant females in the second group 18%. Conclusion: Neither adding a delayed blastocyst negatively affected the good one nor affected the live birth rate but increased multiple pregnancy rates.

Temperature-insensitive and high-precision frequency transfer based on fabricated in-house 1.05 km hollow-core anti-resonant fiber

We have prepared kilometer-scale low-loss hollow-core nested anti-resonant nodeless fibers by improving their structural design,which reduces the difficulty of fabricating low-loss hollow-core fibers over long distances.The lowest loss is 2.7 d B/km at 1506 nm,and this loss is less than 5 d B/km at 1417–1620 nm.High-precision frequency transfer is achieved using the fabricated 1050 m hollow-core fiber by locking the repetition frequency of the optical frequency comb to a rubidium atomic clock.The frequency stability is 1.67×10^(-12)/s and 5.66×10^(-14)/1000 s when the temperature is changed,and no phase compensation device is used.It is an order of magnitude lower compared to that of the conventional single-mode fiber.

Pearson correlation and transfer entropy in the Chinese stock market with time delay

Correlations between two time series,including the linear Pearson correlation and the nonlinear transfer entropy,have attracted significant attention.In this work,we studied the correlations between multiple stock data with the introduction of a time delay and a rolling window.In most cases,the Pearson correlation and transfer entropy share the same tendency,where a higher correlation provides more information for predicting future trends from one stock to another,but a lower correlation provides less.Considering the computational complexity of the transfer entropy and the simplicity of the Pearson correlation,using the linear correlation with time delays and a rolling window is a robust and simple method to quantify the mutual information between stocks.Predictions made by the long short-term memory method with mutual information outperform those made only with selfinformation when there are high correlations between two stocks.

A frequency-domain method for solving linear time delay systems with constant coefficients

In an active control system, time delay will occur due to processes such as signal acquisition and transmission, calculation,and actuation. Time delay systems are usually described by delay differential equations（DDEs）. Since it is hard to obtain an analytical solution to a DDE, numerical solution is of necessity. This paper presents a frequency-domain method that uses a truncated transfer function to solve a class of DDEs. The theoretical transfer function is the sum of infinite items expressed in terms of poles and residues. The basic idea is to select the dominant poles and residues to truncate the transfer function,thus ensuring the validity of the solution while improving the efficiency of calculation. Meanwhile, the guideline of selecting these poles and residues is provided. Numerical simulations of both stable and unstable delayed systems are given to verify the proposed method, and the results are presented and analysed in detail.

Nerve function restoration following targeted muscle reinnervation after varying delayed periods

Targeted muscle reinnervation has been proposed for reconstruction of neuromuscular function in amputees.However,it is unknown whether performing delayed targeted muscle reinnervation after nerve injury will affect restoration of function.In this rat nerve injury study,the median and musculocutaneous nerves of the forelimb were transected.The proximal median nerve stump was sutured to the distal musculocutaneous nerve stump immediately and 2 and 4 weeks after surgery to reinnervate the biceps brachii.After targeted muscle reinnervation,intramuscular myoelectric signals from the biceps brachii were recorded.Signal amplitude gradually increased with time.Biceps brachii myoelectric signals and muscle fiber morphology and grooming behavior did not significantly differ among rats subjected to delayed target muscle innervation for different periods.Targeted muscle reinnervation delayed for 4 weeks can acquire the same nerve function restoration effect as that of immediate reinnervation.

Spray and Dynamic: Advanced Routing in Delay Tolerant Networks

This paper addresses the problem of routing in delay tolerant networks (DTNs). Delay tolerant networks are wireless networks where disconnections occur frequently due to mobility of nodes, failures of energy, the low density of nodes, or when the network extends over long distances. In these cases, traditional routing protocols that have been developed for mobile ad hoc networks prove to be ineffective to the extent of transmitting messages between nodes. To resolve this problem and improve the performance of routing in delay tolerant networks we propose a new routing protocol called Spray and Dynamic;this approach represents an improvement of the spray and wait protocol by combining it with the two protocols: MaxProp and the model of “transfer by delegation” (Custody Transfer). To implement our approach Spray and Dynamic, we have developed a DTN simulator according to DTN network architecture.

Supramolecular Thermally Activated Delayed Fluorescence Materials via Through-Space Charge Transfer

Thermally activated delayed fluorescence(TADF)polymeric materials based on through-space charge transfer(TSCT)have emerged as a highly studied topic in recent years.However,the construction of TSCT TADF materials via a supramolecular approach is still a big challenge.In this work,we report the noncovalent synthesis of TSCT TADF materials using a cyclic peptide-based bottle-brushed supramolecular polymer as a scaffold.By bringing the TSCT donor and acceptor in close proximity in space using the supramolecular scaffold,distinctive TADF emission in both solution and solid states could be achieved.Furthermore,the TADF system could be utilized as a sensitizer to coassemble with fluorescence acceptors to build thermally assisted fluorescence systems,resulting in color-tunable delayed fluorescence with high efficiency and color purity.Our findings provide a facile yet effective approach to designing and fabricating TSCT TADF materials,which might hold great potential for applications in the fields of organic light-emitting diode,bioimaging,and sensing.

Stability and Hopf Bifurcation Analysis of a Predator-Prey Model with Time Delayed Incomplete Trophic Transfer

A new nonlinear predator-prey model with incomplete trophic transfer is introduced. In this model, we assume that the rate of the trophic absorption of the predator is less than the rate of the conversion of consumed prey to predator in the Ivlev-type functional responses. The existence and uniqueness of the positive equilibrium of the model and the stability of the equilibrium of the model are studied under various conditions. Hopf bifurcation analysis of the delayed model is provided.

High-Efficiency Narrow-Band Electro-Fluorescent Devices with Thermally Activated Delayed Fluorescence Sensitizers Combined Through-Bond and Through-Space Charge Transfers

Organic light-emitting diodes utilizing thermally activated delayed fluorescence sensitizers and multiple-resonance(MR)dopants may simultaneously offer high efficiencies and narrow-band emissions,but these devices still face intractable challenges with a lack of design rules for high-performance sensitizers.Here,sensitizers with ortho-arranged donor–acceptors on a(trifluoromethyl)benzene linker have been proposed,which not only facilitate relatively small molecular dipole moments but also combine through-bond and through-space charge transfers for fast reverse intersystem crossing(RISC).

Carbazole ring: A delicate rack for constructing thermally activated delayed fluorescent compounds with through-space charge transfer

Three carbazole derivatives, Ac PTC, Px PTC and Pt PTC, consisting of two 9,9-dimethyl-9,10-dihydroacridine,phenoxazine or phenothiazine donor groups and one diphenyltriazine acceptor group fixed at 1,8,9-positions of a single carbazole ring via phenylene, are designed and synthesized. X-ray diffraction analysis of Ac PTC reveals that there exist multiple π-π interactions between the donor and acceptor groups to form a sandwich-like structural unit with edge-to-face interaction model. The compounds thus show obvious thermally activated delayed fluorescence with through-space charge transfer character and possess considerable photoluminescence quantum yields of up to 73% in doped films with sky-blue to yellow emissions. The solution-processed electroluminescent devices achieve the highest maximum external quantum efficiencies of 10.0%, 11% and 5.6% for Ac PTC, Px PTC and Pt PTC, respectively, with small efficiency roll-offs.

Analysis of on-chip distributed interconnects based on Pade expansion

In this paper, on-chip interconnects are modeled as distributed parameter RLCG transmission lines, based on which the matrix ABCD of interconnects is deduced. With help of the ABCD matrix, a voltage transfer function of an interconnect system, consisting of a driver, interconnect line and load, is obtained analytically in the form of a transcendental function, and it is reduced to a finite order system based on high order Pade approximation. With the reduced-order transfer function, response waveforms with step input can be obtained, and signal delay can be calculated consequently. Two numerical experiments are conducted to demonstrate its efficiency.

Technology of shipboard two-way microwave time synchronization

For the high precision time synchronization demand of ships, advantages and disadvantages of the present time transfer methods are analyzed, the two-way microwave time transfer （TWMTT） method is adopted to resolve the time synchronization problem in the Naval Ship Formation. After expounding the principle and system composition of TWMTT method, the various factors influencing the synchronous precision are analyzed, such as time-interval measurement error, TWMTT equipment delay error, signal propagation error in air, and signal delay error caused by shipping. To improve the time synchronization precision, all the error sources above are deduced with mathematical measures to definite the critical one, and the signal processing measures such as Pseudo code spread spectrum time comparison signal generation technology, FFT fast acquisition technology and precise tracking technology are used into the modem which is the core equipment of the TWMTT. And, calibration method of TWMTT equipment delay are developed. Through theoretical a- nalysis and simulation verification, the precision of shipboard two-way microwave time synchroniza- tion can reach 1 ns.

Acceptor modulation for improving thermally activated delayed fluorescence emitter in through-space charge transfer on spiroskeletons

Through-space charge transfer(TSCT)is regarded as an effective way to develop thermally activated delayed fluorescence(TADF)emitters.Based on this strategy,many molecular frameworks have been proposed,among which spirobased scaffolds have been extensively studied due to their unique advantages.In this work,we developed three emitters SPS,SPO,and SPON,which were constructed with the same donor and various acceptors to explore the influence of acceptor modulation at the C9 position of fluorene for spirostructure TSCT emitters.The results show that the acceptor with too weak electronwithdrawing ability will cause the emitter to not have TADF properties,while the acceptor with too much steric hindrance will weaken the face-to-faceπ-πstacking interaction between donor/acceptor(D/A).Since SPO balances the electron-withdrawing strength and steric hindrance of the acceptor,it achieves the highest external quantum efficiency(EQE)of 17.75%.This work shows that appropriate acceptor selection is essential for the TADF properties and high efficiency of the spirobased scaffold TSCT emitter.

Brain development in children with developmental delay using amide proton transfer-weighted imaging and magnetization transfer imaging

Importance:The process of brain development in children with developmental delay is not well known.Amide proton transfer-weighted(APTw)imaging is a novel molecular magnetic resonance imaging(MRI)technique that can noninvasively detect cytosolic endogenous mobile proteins and peptides involved in the myelination process,and may be useful for providing insights into brain development.Objective:To assess the contribution of amide proton transfer-weighted(APTw)imaging and magnetization transfer(MT)imaging to the evaluation of children with developmental delay(DD).Methods:Fifty-one patients with DD were recruited to this study.The patients were divided into two groups according to the state of myelination assessed on conventional magnetic resonance imaging(MRI).Thirty patients(10 girls,20 boys;age range:1-8 months;median age:4 months)in group A showed delayed myelination on MRI,while 21 patients(3 girls,18 boys;age range:12-36months;median age:25months)in group B showed normal myelination on MRI.Fifty-one age-and sex-matched children with normal developmental quotient(DQ)and normal MRI appearance were recruited as normal controls.Three-slice APTw/MT axial imaging was performed at the level of the centrum semiovale,the basal ganglia and the pons.Quantitative data of the MT ratio(MTR)and APTw were analyzed for multiple brain regions.Independent-samplet-tests were used to compare differences in APTw and MTR signals between the two DD groups and normal controls.Analysis of Covariance was conducted to correct the statistical results.The level of statistical significance was set toP<0.05.Results:For group A,the MTR values were lower in all regions(P=0.004-0.033)compared with the normal controls,while the APTw values were higher in the pons,middle cerebellar peduncle,corpus callosum,frontal white matter,occipital white matter and centrum semiovale(P=0.004-0.040).For Group B,the MTR values were slightly reduced,and the APTw values were slightly increased compared with the normal controls,but the differences were not statistically significant(P>0.05).Interpretation:For DD patients showing signs of delayed myelination on MRI,MTR and APTw imaging can help to diagnose myelination delay by quantifying semi-solid macromolecules and cytosolic endogenous mobile proteins and peptides at a molecular level,providing a new method for comprehensive evaluation of DD.For DD patients with normal myelination on MRI,the clinical values of MTR and APTw imaging remain to be explored.

Will the State-owned Capital Transfer Policy Enhance the Sustainability of the Urban Employee Basic Pension Insurance Fund in China?

To analyze the efect of the state-owned capital transfer policy on the sustainability of China's urban employee basic pension insurance fund(CUEBPIF),this study develops an actuarial model for pension insurance.The results reveal the following:(i)Without policy intervention,the CUEBPIF would face a deficit in 2027 and a cumulative shortfall of RMB207.44 trillion by 2050,and the proportion of fiscal subsidies for the CUEBPIF in the total fiscal expenditure would increase to 12.86 percent in 2050.(i)Based on a delayed retirement policy,the transfer of 10 percent of state-owned capital can delay the onset of the fund deficit by 6 years,and the accumulated shortfall in 2050 would fall to RMB39.42 trillion,and the proportion of fiscal subsidies would decrease by I1.77 percentage points.(ii)The state-owned capital transfer policy can improve the sustainability of the CUEBPIF and reduce the burden of enterprise social security contributions when the transfer ratio increases to 20 percent.

Through-space charge transfer blue polymers containing acridan donor and oxygen-bridged triphenylboron acceptor for highly efficient solution-processed organic light-emitting diodes

Three kinds of through-space charge transfer(TSCT)blue polymers containing non-conjugated polystyrene backbone together with spatially-separated acridan donor and oxygen-bridged triphenylboron acceptors having different substituents of tert-butyl,hydrogen and fluorine are designed and synthesized.The designed TSCT blue polymers possess photoluminescence quantum yields up to 70%in solid-state film,single-triplet energy splitting below 0.1 eV,and typical thermally activated delayed fluorescence(TADF)effect.Meanwhile,the resulting polymers exhibit aggregation-induced emission(AIE)effect with emission intensity increased by up to^27 folds from solution to aggregation state.By changing the substituent of acceptors to tune the charge transfer strength,blue emission with peaks from 444 to 480 nm can be realized for the resulting polymers.Solution-processed organic light-emitting diodes based on the polymers exhibit excellent device performance with Commission Internationale de L’Eclairage(CIE)coordinates of(0.16,0.27),together with the maximum luminous efficiency of 30.7 cd A-1 and maximum external quantum efficiency of 15.0%,which is the best device efficiency for blue TADF polymers.

Triplet fusion delayed fluorescence materials for OLEDs

The development of fluorescent materials capable of harvesting triplet excitons efficiently is of great importance in achieving high-performance low-cost organic light-emitting diodes（OLEDs）.Among the three mechanisms converting triplet to singlet excitons,triplet fusion delayed fluorescence（TFDF） plays a key role in the demonstration of highly efficient and reliable OLEDs,especially blue devices,for practice applications.This review focuses on the recent development of TFDF materials and their applications in OLEDs.Fundamental TFDF mechanism,molecular design principles,and the structure-property relationship of TFDF materials with a particular emphasis on their different excited state characters,are presented and discussed.Moreover,the future perspectives and ongoing challenges of TFDF materials are also highlighted.