Background Nursery pigs undergo stressors in the post-weaning period that result in production and welfare chal-lenges.These challenges disproportionately impact the offspring of primiparous sows compared to those of ...Background Nursery pigs undergo stressors in the post-weaning period that result in production and welfare chal-lenges.These challenges disproportionately impact the offspring of primiparous sows compared to those of mul-tiparous counterparts.Little is known regarding potential interactions between parity and feed additives in the post-weaning period and their effects on nursery pig microbiomes.Therefore,the objective of this study was to investigate the effects of maternal parity on sow and offspring microbiomes and the influence of sow parity on pig fecal microbi-ome and performance in response to a prebiotic post-weaning.At weaning,piglets were allotted into three treat-ment groups:a standard nursery diet including pharmacological doses of Zn and Cu(Con),a group fed a commercial prebiotic only(Preb)based on an Aspergillus oryzae fermentation extract,and a group fed the same prebiotic plus Zn and Cu(Preb+ZnCu).Results Although there were no differences in vaginal microbiome composition between primiparous and mul-tiparous sows,fecal microbiome composition was different(R^(2)=0.02,P=0.03).The fecal microbiomes of primiparous offspring displayed significantly higher bacterial diversity compared to multiparous offspring at d 0 and d 21 post-weaning(P<0.01),with differences in community composition observed at d 21(R^(2)=0.03,P=0.04).When analyzing the effects of maternal parity within each treatment,only the Preb diet triggered significant microbiome distinc-tions between primiparous and multiparous offspring(d 21:R^(2)=0.13,P=0.01;d 42:R^(2)=0.19,P=0.001).Composi-tional differences in pig fecal microbiomes between treatments were observed only at d 21(R^(2)=0.12,P=0.001).Pigs in the Con group gained significantly more weight throughout the nursery period when compared to those in the Preb+ZnCu group.Conclusions Nursery pig gut microbiome composition was influenced by supplementation with an Aspergillus oryzae fermentation extract,with varying effects on performance when combined with pharmacological levels of Zn and Cu or for offspring of different maternal parity groups.These results indicate that the development of nursery pig gut microbiomes is shaped by maternal parity and potential interactions with the effects of dietary feed additives.展开更多
The combination of non-Hermitian physics and Majorana fermions can give rise to new effects in quantum transport systems. In this work, we investigate the interplay of PT-symmetric complex potentials, Majorana tunneli...The combination of non-Hermitian physics and Majorana fermions can give rise to new effects in quantum transport systems. In this work, we investigate the interplay of PT-symmetric complex potentials, Majorana tunneling and interdot tunneling in a non-Hermitian double quantum dots system. It is found that in the weak-coupling regime the Majorana tunneling has pronounced effects on the transport properties of such a system, manifested as splitting of the single peak into three and a reduced 1/4 peak in the transmission function. In the presence of the PT-symmetric complex potentials and interdot tunneling, the 1/4 central peak is robust against them, while the two side peaks are tuned by them. The interdot tunneling only induces asymmetry, instead of moving the conductance peak, due to the robustness of the Majorana modes. There is an exceptional point induced by the union of Majorana tunneling and interdot tunneling. With increased PT-symmetric complex potentials, the two side peaks will move towards each other. When the exceptional point is passed through, these two side peaks will disappear. In the strong-coupling regime, the Majorana fermion induces a 1/4 conductance dip instead of the three-peak structure. PT-symmetric complex potentials induce two conductance dips pinned at the exceptional point. These effects should be accessible in experiments.展开更多
Motivated by recent realizations of spin-1 NaRb mixtures in the experiments[Phys.Rev.Lett.114,255301(2015);Phys.Rev.Lett.128,223201(2022)],we investigate heteronuclear magnetism in the Mott-insulating regime.Different...Motivated by recent realizations of spin-1 NaRb mixtures in the experiments[Phys.Rev.Lett.114,255301(2015);Phys.Rev.Lett.128,223201(2022)],we investigate heteronuclear magnetism in the Mott-insulating regime.Different from the identical mixtures where the boson statistics only admits even parity states from angular momentum composition,for heteronuclear atoms in principle all angular momentum states are allowed,which can give rise to new magnetic phases.While various magnetic phases can be developed over these degenerate spaces,the concrete symmetry breaking phases depend on not only the degree of degeneracy but also the competitions from many-body interactions.We unveil these rich phases using the bosonic dynamical mean-field theory approach.These phases are characterized by various orders,including spontaneous magnetization order,spin magnitude order,singlet pairing order,and nematic order,which may coexist specially in the regime with odd parity.Finally we address the possible parameter regimes for observing these spin-ordered Mott phases.展开更多
Background Fertility declines in high-parity sows.This study investigated whether parity-dependent declines in embryonic survival and reproductive performance could be restored by dietary coenzyme Q10(CoQ10)supplement...Background Fertility declines in high-parity sows.This study investigated whether parity-dependent declines in embryonic survival and reproductive performance could be restored by dietary coenzyme Q10(CoQ10)supplementation.Methods Two experiments were performed.In Exp.1,30 young sows that had completed their 2nd parity and 30 high-parity sows that had completed their 10^(th)parity,were fed either a control diet(CON)or a CON diet supple-mented with 1 g/kg CoQ10(+CoQ10)from mating until slaughter at day 28 of gestation.In Exp.2,a total of 314 post-weaning sows with two to nine parities were fed the CON or+CoQ10 diets from mating throughout gestation.Results In Exp.1,both young and high-parity sows had a similar number of corpora lutea,but high-parity sows had lower plasma CoQ10 concentrations,down-regulated genes involved with de novo CoQ10 synthesis in the endome-trium tissues,and greater levels of oxidative stress markers in plasma and endometrium tissues.High-parity sows had fewer total embryos and alive embryos,lower embryonic survival,and greater embryo mortality than young sows.Dietary CoQ10 supplementation increased the number of live embryos and the embryonic survival rate to levels simi-lar to those of young sows,as well as lowering the levels of oxidative stress markers.In Exp.2,sows showed a parity-dependent decline in plasma CoQ10 levels,and sows with more than four parities showed a progressive decline in the number of total births,live births,and piglets born effective.Dietary supplementation with CoQ10 increased the number of total births,live births,and born effective,and decreased the intra-litter covariation coefficients and the percentage of sows requiring farrowing assistance during parturition.Conclusions Dietary CoQ10 supplementation can improve the embryonic survival and reproductive performance of gestating sows with high parity,probably by improving the development of uterine function.展开更多
Postpartum hemorrhage (PPH) is one of the most adverse obstetric outcomes. Our aim is to detect the risks of multilevel PPH in different cesarean section (CS) groups [including nulliparous CS with indications, nul...Postpartum hemorrhage (PPH) is one of the most adverse obstetric outcomes. Our aim is to detect the risks of multilevel PPH in different cesarean section (CS) groups [including nulliparous CS with indications, nulliparous CS without indications, repeat cesarean (RC), vaginal birth after cesarean (VBAC), cesarean after vaginal birth (CAVB)]. We conducted a retrospective cohort study, and the data on 127 145 women collected from January 2014 to May 2016 and from 35 tertiary hospitals in Shanxi province, China, were reviewed. Based on the measuring results of PPH, an ordered logistic regression model was used to analyze the adjusted PPH risks for each of the CS groups, and comparisons were drawn between them. Finally, a total of 99 066 nulliparous (77.92%) and 28 079 multiparous (22.08%) women were observed. The number of CS cases was 61 117, and the rate for CS was 48.07%. A total of 10 029 women did not show indications for CS and accounted for 16.41% of the CS parturient, whereas 9103 women underwent a repeated cesarean, with a CS frequency of 14.89%. The number of VBAC cases was 989, whose rate was 9.88% in prior CS women. The number (proportions) of PPH was 3658 (2.88%) in L1 (PPH volume: ≥900 and 〈1500 mL), 520 (0.41%) in L2 (PPH volume: ≥1500 and〈2100 mL), and 201 (0.16%) in L3 (PPH volume: ≥2100 mL). The Ln (n= 1, 2, 3, etc.) represented the increasing order of PPH severity. In the adjusted results, compared with spontaneous vaginal delivery (SVD) as the reference group, in the adjusted result for nulliparous, there was a decreased PPH risk in CS with indications (OR: 2.32; CI: 2.04-2.62), which was lower than that of CS without indications (OR: 2.50; CI: 2.01-2.96). The highest PPH risk in all subgroups (i.e. nulliparous and multiparous groups) was observed in the RC (OR: 3.61; CI: 3.16-4.17), which was nearly twice higher than that of the VBAC (OR: 1.82; CI: 1.33-2.52). CAVB (OR: 1.03; CI: 0.65-1.62) showed no significant difference with the reference group. Thus, we deemed that CS should be avoided in nulliparous pregnancies unless indicated, to prevent or reduce the rates for the use of RC or VBAC which are high risks of severe PPH to the parturient women.展开更多
In this paper, we focus on the design of irregular QC-LDPC code based multi-level coded modulation(MLCM) scheme by jointly optimizing the component code rate and the degree distribution of the irregular QC-LDPC compon...In this paper, we focus on the design of irregular QC-LDPC code based multi-level coded modulation(MLCM) scheme by jointly optimizing the component code rate and the degree distribution of the irregular QC-LDPC component code. Firstly, the sub-channel capacities of MLCM systems is analyzed and discussed, based on which the optimal component code rate can be obtained. Secondly, an extrinsic information transfer chart based two-stage searching algorithm is proposed to find the good irregular QC-LDPC code ensembles with optimal component code rates for their corresponding sub-channels. Finally, by constructing the irregular QC-LDPC component codes from the designed ensembles with the aim of possibly enlarging the girth and reducing the number of the shortest cycles, the designed irregular QC-LDPC code based 16QAM and 64QAM MLCM systems can achieve 0.4 dB and 1.2 dB net coding gain, respectively, compared with the recently proposed regular QC-LDPC code based 16QAM and 64QAM MLCM systems.展开更多
The key issue in accelerating method of characteristics(MOC)transport calculations is in obtaining a completely equivalent low-order neutron transport or diffusion equation.Herein,an equivalent low-order angular flux ...The key issue in accelerating method of characteristics(MOC)transport calculations is in obtaining a completely equivalent low-order neutron transport or diffusion equation.Herein,an equivalent low-order angular flux nonlinear finite difference equation is proposed for MOC transport calculations.This method comprises three essential features:(1)the even parity discrete ordinates method is used to build a low-order angular flux nonlinear finite difference equation,and different boundary condition treatments are proposed;(2)two new defined factors,i.e.,the even parity discontinuity factor and odd parity discontinuity factor,are strictly defined to achieve equivalence between the low-order angular flux nonlinear finite difference method and MOC transport calculation;(3)the energy group and angle are decoupled to construct a symmetric linear system that is much easier to solve.The equivalence of this low-order angular flux nonlinear finite difference equation is analyzed for two-dimensional(2D)pin,2D assembly,and 2D C5G7 benchmark problems.Numerical results demonstrate that a low-order angular flux nonlinear finite difference equation that is completely equivalent to the pin-resolved transport equation is established.展开更多
In a quantum key distribution(QKD) system, the error rate needs to be estimated for determining the joint probability distribution between legitimate parties, and for improving the performance of key reconciliation....In a quantum key distribution(QKD) system, the error rate needs to be estimated for determining the joint probability distribution between legitimate parties, and for improving the performance of key reconciliation. We propose an efficient error estimation scheme for QKD, which is called parity comparison method(PCM). In the proposed method, the parity of a group of sifted keys is practically analysed to estimate the quantum bit error rate instead of using the traditional key sampling. From the simulation results, the proposed method evidently improves the accuracy and decreases revealed information in most realistic application situations.展开更多
Fault diagnosis is a key issue of the CCBII(computer controlled brake II) braking system, because the CCBII braking system is very complicated and nonlinear, which may exhibit isolated and multi-component coupled faul...Fault diagnosis is a key issue of the CCBII(computer controlled brake II) braking system, because the CCBII braking system is very complicated and nonlinear, which may exhibit isolated and multi-component coupled faults. A parity space-based method was proposed for fault diagnosis of CCBII braking systems. Firstly, the mathematical models were established according to three function modules of CCBII braking systems where the air fluid theory was utilized. Then, parity vector and threshold function were designed for each output of the system so as to identify more system faults. Fault character matrix was built based on the causal relationship between the output and the fault according to the system function and internal structure. Finally, fault detection and isolation can be realized by the comparison of the observed system output and the fault character matrix. Simulation results show that the proposed method is entirely feasible and effective.展开更多
An experimental study was carried out to quantitati ve ly evaluate the loads acting on the diamond grits during circular sawing of two kinds of typical granite with diamond segmented saw blade. Measurements were mad e...An experimental study was carried out to quantitati ve ly evaluate the loads acting on the diamond grits during circular sawing of two kinds of typical granite with diamond segmented saw blade. Measurements were mad e of the horizontal and vertical force components and the consumed power in order to obtain the tangential and the normal force components. The temperatures at the diamond-granite contact zone were measured using a foil thermocouple. T he measurement, together with the net sawing power, was subsequently used to est imate the energy partition to the granite by a temperature matching technique. B ased on the energy partition values, the temperatures at individual cutting poin ts were estimated using an analytical model. SEM was used to follow the topograp hies of worn diamond segments. The average force acting on each diamond grit was found to be only 4% of the diamond compressive strength measured by a static me thod. The strength disparity of diamond grits and the random protrusion of grits beyond bond matrix should be significant factors in accounting for the wear of diamond grits. The wear of diamond grits was also found to be closely related to the high temperatures generated at individual cutting points and the pop-outs of diamonds from the bond matrix might be mainly attributed to the heat conducte d to the segments.展开更多
The application of protograph low density parity check (LDPC) codes involves the encoding complexity problem. Since the generator matrices are dense, and if the positions of "1" s are irregularity, the encoder nee...The application of protograph low density parity check (LDPC) codes involves the encoding complexity problem. Since the generator matrices are dense, and if the positions of "1" s are irregularity, the encoder needs to store every "1" of the generator matrices by using huge chip area. In order to solve this problem, we need to design the protograph LDPC codes with circular generator matrices. A theorem concerning the circulating property of generator matrices of nonsingular protograph LDPC codes is proposed. The circulating property of generator matrix of nonsingular protograph LDPC codes can be obtained from the corresponding quasi-cyclic parity check matrix. This paper gives a scheme of constructing protograph LDPC codes with circulating generator matrices, and it reveals that the fast encoding algorithm of protograph LDPC codes has lower encoding complexity under the condition of the proposed theorem. Simulation results in ad- ditive white Gaussian noise (AWGN) channels show that the bit error rate (BER) performance of the designed codes based on the proposed theorem is much better than that of GB20600 LDPC codes and Tanner LDPC codes.展开更多
This paper proposes a parity recognition of blade number and manoeuvre intention classification algorithm of rotor target based on the convolutional neural network(CNN) using micro Doppler features. Firstly, the time-...This paper proposes a parity recognition of blade number and manoeuvre intention classification algorithm of rotor target based on the convolutional neural network(CNN) using micro Doppler features. Firstly, the time-frequency spectrograms are acquired from the radar echo by the short-time Fourier transform.Secondly, based on the obtained spectrograms, a seven-layer CNN architecture is built to recognize the blade-number parity and classify the manoeuvre intention of the rotor target. The constructed architecture contains a leaky rectified linear unit and a dropout layer to accelerate the convergence of the architecture and avoid over-fitting. Finally, the spectrograms of the datasets are divided into three different ratios, i.e., 20%, 33% and 50%,and the cross validation is used to verify the effectiveness of the constructed CNN architecture. Simulation results show that, on the one hand, as the ratio of training data increases, the recognition accuracy of parity and manoeuvre intention is improved at the same signal-to-noise ratio(SNR);on the other hand, the proposed algorithm also has a strong robustness: the accuracy can still reach 90.72% with an SNR of – 6 dB.展开更多
The coupled-channels optical method for positron scattering has been applied to investigate resonance states with unnatural parities in a positron-excited hydrogen system. The positronium formation channels and contin...The coupled-channels optical method for positron scattering has been applied to investigate resonance states with unnatural parities in a positron-excited hydrogen system. The positronium formation channels and continuum channel are included via a complex equivalent local potential. Resonance states with angular momenta L =- 1 to L = 2 and parities (-1)L+1 are calculated. Resonance energies and widths are reported and compared with other theoretical calculations. We found that the opening positronium formation channels play an important role in forming nondipole Feshbach resonances.展开更多
基金This study was partially supported by funds from the Agricultural Research,Education,Extension and Technology Transfer(AGREETT)and MNDrive Global Food Ventures Programs,both from the University of MinnesotaPartial funding was supplied by BioZyme,Inc,St.Joseph,Missouri,USA and New Fashion Pork,Jackson,MN,USA.
文摘Background Nursery pigs undergo stressors in the post-weaning period that result in production and welfare chal-lenges.These challenges disproportionately impact the offspring of primiparous sows compared to those of mul-tiparous counterparts.Little is known regarding potential interactions between parity and feed additives in the post-weaning period and their effects on nursery pig microbiomes.Therefore,the objective of this study was to investigate the effects of maternal parity on sow and offspring microbiomes and the influence of sow parity on pig fecal microbi-ome and performance in response to a prebiotic post-weaning.At weaning,piglets were allotted into three treat-ment groups:a standard nursery diet including pharmacological doses of Zn and Cu(Con),a group fed a commercial prebiotic only(Preb)based on an Aspergillus oryzae fermentation extract,and a group fed the same prebiotic plus Zn and Cu(Preb+ZnCu).Results Although there were no differences in vaginal microbiome composition between primiparous and mul-tiparous sows,fecal microbiome composition was different(R^(2)=0.02,P=0.03).The fecal microbiomes of primiparous offspring displayed significantly higher bacterial diversity compared to multiparous offspring at d 0 and d 21 post-weaning(P<0.01),with differences in community composition observed at d 21(R^(2)=0.03,P=0.04).When analyzing the effects of maternal parity within each treatment,only the Preb diet triggered significant microbiome distinc-tions between primiparous and multiparous offspring(d 21:R^(2)=0.13,P=0.01;d 42:R^(2)=0.19,P=0.001).Composi-tional differences in pig fecal microbiomes between treatments were observed only at d 21(R^(2)=0.12,P=0.001).Pigs in the Con group gained significantly more weight throughout the nursery period when compared to those in the Preb+ZnCu group.Conclusions Nursery pig gut microbiome composition was influenced by supplementation with an Aspergillus oryzae fermentation extract,with varying effects on performance when combined with pharmacological levels of Zn and Cu or for offspring of different maternal parity groups.These results indicate that the development of nursery pig gut microbiomes is shaped by maternal parity and potential interactions with the effects of dietary feed additives.
基金Project supported by the National Natural Science Foundation of China (Grant No.11834005)。
文摘The combination of non-Hermitian physics and Majorana fermions can give rise to new effects in quantum transport systems. In this work, we investigate the interplay of PT-symmetric complex potentials, Majorana tunneling and interdot tunneling in a non-Hermitian double quantum dots system. It is found that in the weak-coupling regime the Majorana tunneling has pronounced effects on the transport properties of such a system, manifested as splitting of the single peak into three and a reduced 1/4 peak in the transmission function. In the presence of the PT-symmetric complex potentials and interdot tunneling, the 1/4 central peak is robust against them, while the two side peaks are tuned by them. The interdot tunneling only induces asymmetry, instead of moving the conductance peak, due to the robustness of the Majorana modes. There is an exceptional point induced by the union of Majorana tunneling and interdot tunneling. With increased PT-symmetric complex potentials, the two side peaks will move towards each other. When the exceptional point is passed through, these two side peaks will disappear. In the strong-coupling regime, the Majorana fermion induces a 1/4 conductance dip instead of the three-peak structure. PT-symmetric complex potentials induce two conductance dips pinned at the exceptional point. These effects should be accessible in experiments.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB0500000)the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0301200)+1 种基金the National Natural Science Foundation of China(Grant Nos.12074431,12274384,and 12374252)the Excellent Youth Foundation of Hunan Scientific Committee(Grant No.2021JJ10044).
文摘Motivated by recent realizations of spin-1 NaRb mixtures in the experiments[Phys.Rev.Lett.114,255301(2015);Phys.Rev.Lett.128,223201(2022)],we investigate heteronuclear magnetism in the Mott-insulating regime.Different from the identical mixtures where the boson statistics only admits even parity states from angular momentum composition,for heteronuclear atoms in principle all angular momentum states are allowed,which can give rise to new magnetic phases.While various magnetic phases can be developed over these degenerate spaces,the concrete symmetry breaking phases depend on not only the degree of degeneracy but also the competitions from many-body interactions.We unveil these rich phases using the bosonic dynamical mean-field theory approach.These phases are characterized by various orders,including spontaneous magnetization order,spin magnitude order,singlet pairing order,and nematic order,which may coexist specially in the regime with odd parity.Finally we address the possible parameter regimes for observing these spin-ordered Mott phases.
基金supported by the National Key Research and Development Program of China(2022YFD1301300).
文摘Background Fertility declines in high-parity sows.This study investigated whether parity-dependent declines in embryonic survival and reproductive performance could be restored by dietary coenzyme Q10(CoQ10)supplementation.Methods Two experiments were performed.In Exp.1,30 young sows that had completed their 2nd parity and 30 high-parity sows that had completed their 10^(th)parity,were fed either a control diet(CON)or a CON diet supple-mented with 1 g/kg CoQ10(+CoQ10)from mating until slaughter at day 28 of gestation.In Exp.2,a total of 314 post-weaning sows with two to nine parities were fed the CON or+CoQ10 diets from mating throughout gestation.Results In Exp.1,both young and high-parity sows had a similar number of corpora lutea,but high-parity sows had lower plasma CoQ10 concentrations,down-regulated genes involved with de novo CoQ10 synthesis in the endome-trium tissues,and greater levels of oxidative stress markers in plasma and endometrium tissues.High-parity sows had fewer total embryos and alive embryos,lower embryonic survival,and greater embryo mortality than young sows.Dietary CoQ10 supplementation increased the number of live embryos and the embryonic survival rate to levels simi-lar to those of young sows,as well as lowering the levels of oxidative stress markers.In Exp.2,sows showed a parity-dependent decline in plasma CoQ10 levels,and sows with more than four parities showed a progressive decline in the number of total births,live births,and piglets born effective.Dietary supplementation with CoQ10 increased the number of total births,live births,and born effective,and decreased the intra-litter covariation coefficients and the percentage of sows requiring farrowing assistance during parturition.Conclusions Dietary CoQ10 supplementation can improve the embryonic survival and reproductive performance of gestating sows with high parity,probably by improving the development of uterine function.
基金This study was supported by the National Natural Science Foundation of China (No. 71173081).
文摘Postpartum hemorrhage (PPH) is one of the most adverse obstetric outcomes. Our aim is to detect the risks of multilevel PPH in different cesarean section (CS) groups [including nulliparous CS with indications, nulliparous CS without indications, repeat cesarean (RC), vaginal birth after cesarean (VBAC), cesarean after vaginal birth (CAVB)]. We conducted a retrospective cohort study, and the data on 127 145 women collected from January 2014 to May 2016 and from 35 tertiary hospitals in Shanxi province, China, were reviewed. Based on the measuring results of PPH, an ordered logistic regression model was used to analyze the adjusted PPH risks for each of the CS groups, and comparisons were drawn between them. Finally, a total of 99 066 nulliparous (77.92%) and 28 079 multiparous (22.08%) women were observed. The number of CS cases was 61 117, and the rate for CS was 48.07%. A total of 10 029 women did not show indications for CS and accounted for 16.41% of the CS parturient, whereas 9103 women underwent a repeated cesarean, with a CS frequency of 14.89%. The number of VBAC cases was 989, whose rate was 9.88% in prior CS women. The number (proportions) of PPH was 3658 (2.88%) in L1 (PPH volume: ≥900 and 〈1500 mL), 520 (0.41%) in L2 (PPH volume: ≥1500 and〈2100 mL), and 201 (0.16%) in L3 (PPH volume: ≥2100 mL). The Ln (n= 1, 2, 3, etc.) represented the increasing order of PPH severity. In the adjusted results, compared with spontaneous vaginal delivery (SVD) as the reference group, in the adjusted result for nulliparous, there was a decreased PPH risk in CS with indications (OR: 2.32; CI: 2.04-2.62), which was lower than that of CS without indications (OR: 2.50; CI: 2.01-2.96). The highest PPH risk in all subgroups (i.e. nulliparous and multiparous groups) was observed in the RC (OR: 3.61; CI: 3.16-4.17), which was nearly twice higher than that of the VBAC (OR: 1.82; CI: 1.33-2.52). CAVB (OR: 1.03; CI: 0.65-1.62) showed no significant difference with the reference group. Thus, we deemed that CS should be avoided in nulliparous pregnancies unless indicated, to prevent or reduce the rates for the use of RC or VBAC which are high risks of severe PPH to the parturient women.
基金supported by National Natural Science Foundation of China(No.61571061)
文摘In this paper, we focus on the design of irregular QC-LDPC code based multi-level coded modulation(MLCM) scheme by jointly optimizing the component code rate and the degree distribution of the irregular QC-LDPC component code. Firstly, the sub-channel capacities of MLCM systems is analyzed and discussed, based on which the optimal component code rate can be obtained. Secondly, an extrinsic information transfer chart based two-stage searching algorithm is proposed to find the good irregular QC-LDPC code ensembles with optimal component code rates for their corresponding sub-channels. Finally, by constructing the irregular QC-LDPC component codes from the designed ensembles with the aim of possibly enlarging the girth and reducing the number of the shortest cycles, the designed irregular QC-LDPC code based 16QAM and 64QAM MLCM systems can achieve 0.4 dB and 1.2 dB net coding gain, respectively, compared with the recently proposed regular QC-LDPC code based 16QAM and 64QAM MLCM systems.
基金the National Key R&D Program of China(No.2018YFE0180900).
文摘The key issue in accelerating method of characteristics(MOC)transport calculations is in obtaining a completely equivalent low-order neutron transport or diffusion equation.Herein,an equivalent low-order angular flux nonlinear finite difference equation is proposed for MOC transport calculations.This method comprises three essential features:(1)the even parity discrete ordinates method is used to build a low-order angular flux nonlinear finite difference equation,and different boundary condition treatments are proposed;(2)two new defined factors,i.e.,the even parity discontinuity factor and odd parity discontinuity factor,are strictly defined to achieve equivalence between the low-order angular flux nonlinear finite difference method and MOC transport calculation;(3)the energy group and angle are decoupled to construct a symmetric linear system that is much easier to solve.The equivalence of this low-order angular flux nonlinear finite difference equation is analyzed for two-dimensional(2D)pin,2D assembly,and 2D C5G7 benchmark problems.Numerical results demonstrate that a low-order angular flux nonlinear finite difference equation that is completely equivalent to the pin-resolved transport equation is established.
基金Project supported by the National Basic Research Program of China(Grant Nos.2011CBA00200 and 2011CB921200)the National Natural Science Foundation of China(Grant Nos.61101137,61201239,and 61205118)
文摘In a quantum key distribution(QKD) system, the error rate needs to be estimated for determining the joint probability distribution between legitimate parties, and for improving the performance of key reconciliation. We propose an efficient error estimation scheme for QKD, which is called parity comparison method(PCM). In the proposed method, the parity of a group of sifted keys is practically analysed to estimate the quantum bit error rate instead of using the traditional key sampling. From the simulation results, the proposed method evidently improves the accuracy and decreases revealed information in most realistic application situations.
基金Projects(61071096,61073103,61003233) supported by the National Natural Science Foundation of ChinaProjects(20100162110012,20110162110042) supported by Doctoral Program of Higher Education,China
文摘Fault diagnosis is a key issue of the CCBII(computer controlled brake II) braking system, because the CCBII braking system is very complicated and nonlinear, which may exhibit isolated and multi-component coupled faults. A parity space-based method was proposed for fault diagnosis of CCBII braking systems. Firstly, the mathematical models were established according to three function modules of CCBII braking systems where the air fluid theory was utilized. Then, parity vector and threshold function were designed for each output of the system so as to identify more system faults. Fault character matrix was built based on the causal relationship between the output and the fault according to the system function and internal structure. Finally, fault detection and isolation can be realized by the comparison of the observed system output and the fault character matrix. Simulation results show that the proposed method is entirely feasible and effective.
基金ProjectsupportedbytheNationalNaturalScienceFoundationofChina (NSFC ) (No .5 0 1 75 0 3 0 ) ,theEducationDepartmentofFujianProvinceinChina (No .JA0 0 2 3 6) ,andtheNaturalScienceFoundationofFujianProvinceinChina (No .F0 1 1 0 0 0 2 )
文摘An experimental study was carried out to quantitati ve ly evaluate the loads acting on the diamond grits during circular sawing of two kinds of typical granite with diamond segmented saw blade. Measurements were mad e of the horizontal and vertical force components and the consumed power in order to obtain the tangential and the normal force components. The temperatures at the diamond-granite contact zone were measured using a foil thermocouple. T he measurement, together with the net sawing power, was subsequently used to est imate the energy partition to the granite by a temperature matching technique. B ased on the energy partition values, the temperatures at individual cutting poin ts were estimated using an analytical model. SEM was used to follow the topograp hies of worn diamond segments. The average force acting on each diamond grit was found to be only 4% of the diamond compressive strength measured by a static me thod. The strength disparity of diamond grits and the random protrusion of grits beyond bond matrix should be significant factors in accounting for the wear of diamond grits. The wear of diamond grits was also found to be closely related to the high temperatures generated at individual cutting points and the pop-outs of diamonds from the bond matrix might be mainly attributed to the heat conducte d to the segments.
基金supported by Beijing Natural Science Foundation(4102050)the National Natural Science of Foundation of China(NSFC)-Korea Science and Engineering Foundation (KOSF) Joint Research Project of China and Korea (60811140343)
文摘The application of protograph low density parity check (LDPC) codes involves the encoding complexity problem. Since the generator matrices are dense, and if the positions of "1" s are irregularity, the encoder needs to store every "1" of the generator matrices by using huge chip area. In order to solve this problem, we need to design the protograph LDPC codes with circular generator matrices. A theorem concerning the circulating property of generator matrices of nonsingular protograph LDPC codes is proposed. The circulating property of generator matrix of nonsingular protograph LDPC codes can be obtained from the corresponding quasi-cyclic parity check matrix. This paper gives a scheme of constructing protograph LDPC codes with circulating generator matrices, and it reveals that the fast encoding algorithm of protograph LDPC codes has lower encoding complexity under the condition of the proposed theorem. Simulation results in ad- ditive white Gaussian noise (AWGN) channels show that the bit error rate (BER) performance of the designed codes based on the proposed theorem is much better than that of GB20600 LDPC codes and Tanner LDPC codes.
基金supported by the National Natural Science Foundation of China (61901514)the Young Talent Program of Air Force Early Warning Academy (TJRC425311G11)。
文摘This paper proposes a parity recognition of blade number and manoeuvre intention classification algorithm of rotor target based on the convolutional neural network(CNN) using micro Doppler features. Firstly, the time-frequency spectrograms are acquired from the radar echo by the short-time Fourier transform.Secondly, based on the obtained spectrograms, a seven-layer CNN architecture is built to recognize the blade-number parity and classify the manoeuvre intention of the rotor target. The constructed architecture contains a leaky rectified linear unit and a dropout layer to accelerate the convergence of the architecture and avoid over-fitting. Finally, the spectrograms of the datasets are divided into three different ratios, i.e., 20%, 33% and 50%,and the cross validation is used to verify the effectiveness of the constructed CNN architecture. Simulation results show that, on the one hand, as the ratio of training data increases, the recognition accuracy of parity and manoeuvre intention is improved at the same signal-to-noise ratio(SNR);on the other hand, the proposed algorithm also has a strong robustness: the accuracy can still reach 90.72% with an SNR of – 6 dB.
基金Project supported by the National Natural Science Foundation of China(Grant No.10674055)
文摘The coupled-channels optical method for positron scattering has been applied to investigate resonance states with unnatural parities in a positron-excited hydrogen system. The positronium formation channels and continuum channel are included via a complex equivalent local potential. Resonance states with angular momenta L =- 1 to L = 2 and parities (-1)L+1 are calculated. Resonance energies and widths are reported and compared with other theoretical calculations. We found that the opening positronium formation channels play an important role in forming nondipole Feshbach resonances.