如何解决危机矿山深边部资源勘探问题，是我国矿业界一个非常紧迫的研究课题，笔者针对危机矿山深边部资源勘探的特殊性和国内外相关研究与应用，详细分析了现有地球物理勘探方法技术及其在危机矿山深边部接替资源勘探的适用，最后结合我国几个大型危机矿山深边部资源勘探工作，介绍了几种有效的地球物理方法的勘探效果，供其他危机矿山在进行深边部资源勘探加以借鉴。

This study was conducted to investigate effects of leaves of mulberry tree (Morus alba) as a protein supplement to isonitrogenously replace rapeseed meal (RSM) on performance of growing lambs offered ammoniated rice straw (ABRS) (Trial 1), and to evaluate the digestive characteristics of the ABRS supplemented with different ratios of RSM and mulberry leaves in terms of in vitro gas production (Trial 2). In Trial 1, 45 Huzhou lambs were divided into

In vitro gas production was measured to investigate associative effects of untreated and chemically treated rice straw (RS) and of RS and grass hay or mulberry leaves (ML). The RS was treated with NaOH, urea, or (NH4)HCO3. Cumulative gas production was recorded at 2, 4, 6, 8, 12, 16, 24, 36, 48, 60, 72, and 96h of incubation, and the Gompertz function was used to describe the kinetics of gas production. Treatment with NaOH, urea, and NH4HCO3 increased (P<0.05) gas production at 48h by 55, 52, and 37% and the maximum rate of gas production of RS from 0.64 to 1.51, 1.27, and 1.13mL/h, respectively. The inclusion of treated straws, hay, and ML in a mixture with RS at increasing proportions (25, 50, 75, 100%) elevated cumulative gas production and its rate. Maximum gas production was not different between the RS and its mixtures with the treated straws, but inclusion of hayinto RS or NH4HCO3-treated RS increased the maxi-mum gas production. Associative effects were defined as the difference between the observed gas production for the mixtures and the sum of the individual component feeds. The NaOH-treated RS, included at higher proportions, had positive associative effects at all times of incubation <96h; effects were negative or absent at 96h. No effects were observed with mixtures of RS with urea-treated RS. The NH4HCO3-treated RS mixture tended to have negative associative effects at all three levels. Positive associative effects (P<0.05) were observed for both RS and NH4HCO3-treated RS at almost all inclusion levels of hay or ML after 12 to 96 h of incubation. The response was more pronounced with ML than with hay. Associative effects generally declined with duration of incubation. We conclude that positive associative effects on in vitro gas production occurred more consistently when RS was incubated in mixtures with hay or ML than when incubated in mixtures with chemically treated RS.

A series of nitrogen (N) balance trials were carried out to investigate the requirement of crude protein (CP) for maintenance in Shaoxing Ducks. The N balance was determined for five periods from the age of 1 day to 28 weeks (0-4 weeks, 5-8 weeks, 9-16 weeks, 17-20 weeks, 20-28 weeks). Fifteen ducks were used in each period. The birds were divided into three equal groups and fed on the diets with equal metabolizable energy (ME) and different contents of CP (low, medium and high). The N requirements for maintenance were estimated from the relationship between the N retention and N intake (NI). Following the above series of N balance test, 25 ducks at the age of 10 weeks were used in an N balance test with N-free ration. The birds were divided into five groups and offered N-free ration at levels of 100, 75, 50, 25 and 0g per day, respectively. The net protein utilization (NPU) ranged from 0.45 to 0.53 and increased with the advancing age of ducks, but no significant difference was found among different contents of the dietary CP. The estimated N requirement for maintenance was, on an average, 455mg/kg BW0.75 per day, which was equal to 2.8g CP/kg BW0.75 per day. The result from the trial in the Nfree ration showed that the value of N requirement for maintenance was 467mg/kg BW0.75 per day, conforming the results in the series of N balance test. The lower intake of N-free ration resulted in more N excretion suggesting that protein catabolism may occur in the body of birds to meet maintenance requirements forNwhen the dietary NI was very low.