The I-V characteristic of GaN-based p-i-n ultraviolet detector is presented. It is measured at different temperatures and analyzed with changing temperature. The ideality factor of the device is 2.09 at room temperatu...The I-V characteristic of GaN-based p-i-n ultraviolet detector is presented. It is measured at different temperatures and analyzed with changing temperature. The ideality factor of the device is 2.09 at room temperature. The maximum ideality factor is 2.14 at 100 ℃, which declines above 100 ℃, and the minimum ideality factor is 1.26 at 300 ℃. The coefficient of forward voltage vs. temperature is -1.97 mV/℃ with a forward current of 1 mA. Based on double injection model, the deep lying impurity activation energy in the i-region is 0.1 343 eV.展开更多
Channel estimation for orthogonal frequency division multiplexing （OFDM） system has attracteo widespread attention. In this paper, a novel efficient two-dimensional （2-D） channel estimation algorithm based on fast...Channel estimation for orthogonal frequency division multiplexing （OFDM） system has attracteo widespread attention. In this paper, a novel efficient two-dimensional （2-D） channel estimation algorithm based on fast Fourier transform （FFT） is proposed for a time-variant, frequency-selective wideband wireless channel. Both theoretical analysis and simulation results are addressed in the paper. The simulation results prove that the proposed algorithm has simpler implementation, better performance and wider application than other traditional deeision-direeted algorithms.展开更多
A new approach to the research into the distribution of prime pairs is developed, attached with corollaries about the distribution of prime triplets and generally about that of prime h-tuplets. It differs from the usu...A new approach to the research into the distribution of prime pairs is developed, attached with corollaries about the distribution of prime triplets and generally about that of prime h-tuplets. It differs from the usual methods(involving the sieve method) for this kind of research, and bases on Chebyshev inequality and on the computation of average concentration of all the related subsets, and leads to the proofs of following lemma and theorem, attached with four corollaries:[Lemma 1] Among all the prime-pair-subsets there exists at least one such subset (namely one of the sets of generalized prime twins) which is an infinite set.[Theorem 1] All the prime-pair-subsets (namely all sets of generalized prime twins) or infinitely many prime-pair-subsets are infinite sets.[Corollary 1] Among all the prime-triplet-subsets there exists at least one such subset which is an infinite set.[Corollary 2] All the prime-triplet-subsets or infinitely many prime-triplet-subsets are infinite sets.[Corollary 3] Among all the prime-h-tuplet-subsets there exists at least one such subset which is an infinite set, where h is an arbitrary finite integer ≥2.[Corollary 4] All the prime-h-tuplet-subsets or infinitely many prime-h-tuplet-subsets are infinite sets, where h is an arbitrary finite integer ≥2.展开更多
文摘The I-V characteristic of GaN-based p-i-n ultraviolet detector is presented. It is measured at different temperatures and analyzed with changing temperature. The ideality factor of the device is 2.09 at room temperature. The maximum ideality factor is 2.14 at 100 ℃, which declines above 100 ℃, and the minimum ideality factor is 1.26 at 300 ℃. The coefficient of forward voltage vs. temperature is -1.97 mV/℃ with a forward current of 1 mA. Based on double injection model, the deep lying impurity activation energy in the i-region is 0.1 343 eV.
基金the High Technology Research and Development Programme of China(No.2002AA123041)the National Natural Science Foundation of China(No.90104013)Beijing Municipal Science &.Technology Commission(No.KM200610005018)
文摘Channel estimation for orthogonal frequency division multiplexing （OFDM） system has attracteo widespread attention. In this paper, a novel efficient two-dimensional （2-D） channel estimation algorithm based on fast Fourier transform （FFT） is proposed for a time-variant, frequency-selective wideband wireless channel. Both theoretical analysis and simulation results are addressed in the paper. The simulation results prove that the proposed algorithm has simpler implementation, better performance and wider application than other traditional deeision-direeted algorithms.
文摘A new approach to the research into the distribution of prime pairs is developed, attached with corollaries about the distribution of prime triplets and generally about that of prime h-tuplets. It differs from the usual methods(involving the sieve method) for this kind of research, and bases on Chebyshev inequality and on the computation of average concentration of all the related subsets, and leads to the proofs of following lemma and theorem, attached with four corollaries:[Lemma 1] Among all the prime-pair-subsets there exists at least one such subset (namely one of the sets of generalized prime twins) which is an infinite set.[Theorem 1] All the prime-pair-subsets (namely all sets of generalized prime twins) or infinitely many prime-pair-subsets are infinite sets.[Corollary 1] Among all the prime-triplet-subsets there exists at least one such subset which is an infinite set.[Corollary 2] All the prime-triplet-subsets or infinitely many prime-triplet-subsets are infinite sets.[Corollary 3] Among all the prime-h-tuplet-subsets there exists at least one such subset which is an infinite set, where h is an arbitrary finite integer ≥2.[Corollary 4] All the prime-h-tuplet-subsets or infinitely many prime-h-tuplet-subsets are infinite sets, where h is an arbitrary finite integer ≥2.
