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51.
Simpson T.B. Day T. Doft F. Malley M.M. Sutton G.W. 《Quantum Electronics, IEEE Journal of》1993,29(9):2489-2496
We report measurements which show that an actively stabilized cw mode-locked Nd:YLF laser, in combination with a flashlamp-pumped Nd:glass amplifier, can achieve better than 1 cm resolution of distant rotating targets using range-Doppler imaging. To do this, we have produced trains of 50 ps mode-locked pulses with less than 25 kHz peak-to-peak optical frequency broadening and jitter of the laser modes. This frequency stability is achieved by active control of the oscillator cavity length using an external cavity as a reference. Cavity length stabilization can also reduce mode-locked laser timing jitter if the jitter is caused by cavity optical path length changes common to all laser modes. In our laser, however, the active optical-frequency-stabilization did not significantly improve laser pulse timing stability from the approximate 2-ps jitter levels achieved in our passively stabilized cavity. Analysis of the data indicates that a significant fraction of the timing jitter was due to laser cavity path length changes that varied from mode to mode 相似文献
52.
A Brasilian water bread was formulated with wheat flour (100%), salt (2%), yeast (5%), water (60%), fungal amylase (130 SKB/100g wheat flour), ascorbic acid (0.02%), and polysorbate-60 (1%). To the formulation was added Lysine.HCl at levels of 0.1, 0.2, 0.3, 0.4, and 0.5% as related to wheat flour in the formulation. The breads (fortified and control) were baked at 220°C for 20 min. The retention of lysine was estimated by measuring the free Lysine·HCl in bread with FDNB. A regression equation was developed relating the input and retention of lysine, which indicated a loss or destruction of 11.3% of added lysine during baking process. 相似文献
53.
A new synchronisation method for satellite-switched time-division multiple-access systems is described. It is shown that this method has some significant system benefits, and involves a small increase in satellite hardware complexity. 相似文献
54.
The Australian lungfish (Neoceratodus forsteri) responds to intravenous injections of 0.63 ng/kg or more of arginine vasotocin with increased dorsal aortic blood pressure, inulin clearance, urine flow, and tubular rejection of Na+. Single injections of 1 ng/kg or more of angiotensin II or norepinephrine also increase dorsal aortic pressure but do not cause consistent diuresis and natriuresis, Continuous infusions of angiotensin II or repeated injections of norepinephrine produce sustained hypertension and more modest diuresis and natriuresis than are seen after injections of arginine vasotocin that cause less hypertension. Infusions of isosmolar or hyposmolar NaCl solutions increase blood pressure, inulin clearance, urine flow, and tubular Na+ rejection in a manner resembling the response to argininge vasotocoin injections. These data are consistent with the hypothesis that arginine vasotocin is released in response to volume expansion in lungfishes and that it may act on the kidney as a diuretic and natriuretic hormone. They do not rule out a more direct action of expansion on renal functions. 相似文献
55.
RM Gipstein JW Coburn DA Adams DB Lee KP Parsa A Sellers WN Suki SG Massry 《Canadian Metallurgical Quarterly》1976,136(11):1273-1280
Eleven patients with chronic renal failure and presumed secondary hyperparathyroidism developed a syndrome of medial calcinosis of the arteries and painful ischemic ulcers of the fingers, legs, or thighs, or any combination of the three. Five patients required maintenance hemodialysis; six had functioning renal homografts. Severe hyperphosphatemia had existed in each; seven showed roentgenographic evidence of subperiosteal resorption. Similarities are evident between the lesions and experimentally produced calciphylaxix. The lesions demonstrated a relentless, progressive course, with serious morbidity and mortality. Hyperplastic or adenomatours parathyroid tissue was removed from ten of 11 patients unergoing surgical procedures; healing followed in seven patients. Treatment with phosphate-binding antacids to lower serum phosphorus levels may prevent this syndrome. Total or subtotal parathyroidectomy should be considered when ischemic skin lesions appear in uremic patients or in renal transplant recipients. 相似文献
56.
57.
Management of patients irradiated for oral cancer should include consideration of their oral health prior to, and after, radiation therapy. Data from 130 patients, followed for a period of 1 to 10 years, are presented and evaluated. The philosophy of retention and maintenance of as many teeth as possible is supported by this data. Extraction of teeth with severe periodontal disease after irradiation also proves to be a relatively safe operation. Osteoradionecrosis tends to be limited in extent and is generally well tolerated by the patient when treated conservatively. A treatment regimen is presented that significantly reduces the morbidity from therapeutic irradiation of the jaws. A comprehensive dental evaluation and follow-up plan coupled with patient cooperation are instrumental to the success of this program. 相似文献
58.
DA Greene 《Canadian Metallurgical Quarterly》1976,102(4):241-243
An unusual congenital tracheal anomaly is described. Complete (closed) tracheal rings, occupying the entire length of the trachea, have seldom been reported. Most affected patients succumb to respiratory infections in early infancy. Diagnosis of this anomaly is difficult during life, but radiographic and endoscopic examinations may be revealing. There is no known definitive treatment, although the airway may be managed long enough for body growth to relieve the obstruction. This rare anomaly should be considered in those cases of intermittent respiratory obstruction that are not associated with other more common causes of stridor. 相似文献
59.
60.
The kinetics of the male gametogenesis during the pregonadal period, prespermatogenesis, and "early" spermatogenesis has been described in detail. Concerning spermatogenesis in the adult individual reference is made to the articles of Courot, Hochereau-de Reviers and Ortavant (1970) and of Clermont (1972). The comparison of female and male gametogenesis (Fig. 1) shows that the "gonia stage" (asterisks) of the female germ cells is limited to one proliferation wave only, whereas the "gonia stage" of the male germ cells consists of a first proliferation wave, comparable to that of oogonia, a preparative phase to initiate spermatogenesis, and a second proliferation wave with renewal and differentiation of the spermatogonia. Germ cells in the "gonia stage" are highly sensitive towards ionising radiation and cytostatic drugs. 相似文献